Newsletter No. 89, November 2006
  1. Notes from the Editor - Christine Jones
  2. The View from the HEAD Chair - Steve Murray
  3. News from NASA Headquarters - Lou Kaluzienski and Rick Harnden
  4. HEAD in the News - Ilana Harrus, Christopher Wanjek and Megan Watzke
  5. Chandra X-ray Observatory Operations Report - Roger Brissenden and Martin Weisskopf
  6. XMM-Newton Mission News - Randall Smith and Phil Plait
  7. INTEGRAL Mission News - Christoph Winkler
  8. RHESSI Mission News - David Smith
  9. Swift Mission News - Padi Boyd, Lynn Cominsky, Neil Gehrels & Phil Plait
  10. RXTE News - Padi Boyd, Gail Rohrbach, Evan Smith, Jean Swank, Craig Markwardt, Tod Strohmayer
  11. Suzaku Mission News - Koji Mukai and Ilana Harrus
  12. GLAST Mission News - Christopher Wanjek, Steven Ritz and Phil Plait
  13. Constellation-X News -- Mike Garcia
  14. LISA News -- Bonny Schumaker
  15. Meeting Announcements




from the Editor - Christine Jones, HEAD Secretary-Treasurer, headsec@cfa.harvard.edu, 617-495-7137

HEAD only delivers the table-of-contents for HEADNEWS into your mailbox. The newsletter itself can be found online at http://www.aas.org/head/headnews/headnews.nov06.html.

A very successful HEAD Division meeting was held in San Francisco from October 4-6. Our thanks to John Vallerga and the Eureka Scientific team for organizing the meeting (including the dinner cruise and fireworks!) and to Judy Johnson of the AAS for putting together the program abstracts. Pictures from the meeting can be found at http://lheawww.gsfc.nasa.gov/users/imh/HEAD2006/

Ballots for the HEAD election of three new members of the Executive Committee have been emailed to HEAD members. The candidates are Steve Boggs, Wei Cui, Mike Eracleous, Vicky Kalogera, Cole Miller, and Ron Remillard. Please remember to vote before the December 15, 2006 deadline.

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2. The View from the HEAD Chair - Stephen Murray

The big news is that the HEAD meeting in San Francisco, October 4-7, 2006 was a huge success! It was the largest meeting of the HEAD (> 430 registrations), topping even the Hawaii 2000 event. Not only was the meeting large in attendance, but it was also large in content. Thanks to all of the participants for bringing such an array of new results to the meeting. A special thanks to the conference organizers from Eureka Scientific and also the local organizing committee from CU Berkeley. At the meeting the David N. Schramm Award for High Energy Astrophysics Science Journalism was awarded to Trudy Bell for her articles on LIGO. The award was presented at the meeting banquet.

There will be two special HEAD sessions at the January AAS meeting in Seattle. One will be on Short GRB's and other on GLAST. We will also have a Rossi Prize Lecture session featuring three talks by the winners, Tod Strohmayer, Deepto Chakrabarty, and Rudy Wijnands. The annual HEAD business meeting is also scheduled at Seattle, I look forward to seeing many of you there.

During the HEAD-AAS meeting, the Executive Committee met to being the planning process for our next divisional meeting. It will be held in April 2008, and most likely will be sited in the San Francisco Bay Area. Mark your calendars for this next meeting and stay tuned for more details as they are developed.

As everyone knows, there is very little firmly in the NASA science plan beyond 2010. For High Energy Astrophysics, the launch of GLAST in 2007 is the last new mission that is approved and scheduled. As a result High Energy Astrophysics faces a potential hiatus of new missions in the decade of 2010. The Beyond Einstein program, is an approved program with two flagship missions (LISA and Constellation-X) and three probes (Black Hole Finder, Cosmic Inflation, and Dark Energy). However, the order in which these missions will be carried out, and their time frames, are not yet established. NASA and DOE have asked the NRC Board on Physics and Astronomy to conduct a review of the BE Program and to make a recommendation as to which mission should go first, so that it might start before the end of this decade (i.e., before the next Decadal Survey). The review will also provide some input to the Decadal Survey regarding the ordering of the remaining BE missions. This effort is just getting underway, and more details including the committee members can be found at this web site: http://www7.nationalacademies.org/bpa/Beyond_Einstein.html

Once again, a reminder about the next HEAD meeting April 2008, and the closer HEAD sessions at the January AAS meeting in Seattle. See you there.

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3. News from NASA Headquarters - Rick Harnden and Lou Kaluzienski

Personnel developments

Lou Kaluzienski has returned to his position as High Energy Astrophysics Discipline Scientist in the Astrophysics Division at NASA Headquarters from a 14-month detail at Goddard Space Flight Center where he served as chief of the Observational Cosmology Lab. He rejoins his HEA colleagues Wilt Sanders and Rick Harnden who have both extended their assignments in the Division for an additional two years. In addition to his Discipline Scientist responsibilities, Wilt has assumed the position of Division Lead for the R&A program, which includes oversight of the APRA, ATP, and ADP programs. Rick will continue serving as Program scientist on the GLAST, Swift, and INTEGRAL missions in addition to managing the gamma-ray portion of the HEA SR&T program.

The advertisement for the currently vacant position of Astrophysics Division Director will close on October 31. Rick Howard has been acting in that capacity for the past 8 months and it is anticipated that a selection will be made as soon as the normal SES administrative process permits. The Associate Administrator for the Science Mission Directorate, Mary Cleave, has announced her intent to retire next Spring. It is expected that an announcement for the position will be released in late 2006/early 2007.

Selection Announcements

As of this writing, the selection of proposals submitted in response to the ROSES-06 solicitation for participation in the Astronomy and Physics Research & Analysis (APRA) Program will be announced by the end of October. The notification letters are in final preparation and their release has been awaiting resolution of lingering budget issues.

The review of proposals submitted in response to the Astrophysics Theory Program/Beyond Einstein Foundation Science (ATP/BEFS) Program solicitation has been completed and formulation of the selection recommendation is in preparation. The ATP/BEFS lead scientist, Ron Hellings, anticipates that the results will be announced before the end of November.

Budget News

NASA is currently operating under a Continuing Resolution which is scheduled to expire in mid-November. Limited funding is available for the development/operation of ongoing flight programs and partial support of the R&A program. Due to the funding situation, some delays to grant renewals nominally planned for the first quarter of the fiscal year are anticipated.

NAS Review of Beyond Einstein Program

NASA has asked the Space Studies Board of the NRC to perform an assessment of the missions comprising the Beyond Einstein (BE) Program, including the two Einstein Observatories (Con-X and LISA) and three Einstein Probes (Black Hole Finder Probe, Joint Dark Energy Mission, and Inflation Probe). Specifically, the SSB has been charged with the task of identifying which of the five BE missions should proceed first and to assist NASA in its investment strategy for future technology development within the BE program. The criteria for this assessment include the potential scientific impact and the realism of the preliminary technology and management plans and cost estimates of each mission. The requested timeframe for completion of this study is early September of next year.


Due to the lateness of the planned release date of the ROSES-07 solicitation and our desire to maintain the same annual schedule for the APRA program, it is currently expected that next year's APRA solicitation will be issued as an amendment to the ROSES-06 announcement. Based upon SMD policy, all amendments to ROSES-06 must be released no later than January 5, 2007.

4. HEAD in the News - Ilana Harrus, HEAD Press Officer, Christopher Wanjek, Structure and Evolution of the Universe Senior Science Writer, and Megan Watzke, Chandra Press Officer

There is much news to report since the last newsletter.

The April press telecon coordinated by NASA Goddard featuring news of the first complete gravitational wave computer simulation of a black hole merger was a big hit. Although esoteric, the result (with help of killer graphics and a well-coordinated press event) scored the front-page above-the-fold lead story in the New York Times Science Times, and made the other major papers (Washington Post, USA Today), all the science magazines, as well as national radio and local TV.

RXTE had a few solid hits. Tod Strohmayer and Anna Watts' observation of neutron star seismology (May) made USA Today, science magazines and German newspapers. John Middleditch's result about neutron star glitches (June) scored New Scientist and various website coverage. In July, the result on RS Ophiuchi (Jennifer Sokoloski et al.) garnered broad coverage on the web, including CNN, in the science magazines, and in European newspapers such as The Times.

XMM-Newton had a hit in June with a result on Abell 3266 (Finoguenov et al.). It secured coverage in USA Today, L.A. Times, and various web sites and magazines. Andrea De Luca et al. followed with an RCW103 observation (July), which received modest coverage on Space.Com, New Scientist and the UPI newswire.

INTEGRAL had some coverage for Volker Beckman's hard X-ray census (July), in Space.Com and European outlets.

Chandra results were featured in three NASA's phone-in press conferences, known as "media telecons." All three events generated significant coverage, but the result on dark matter (August 21st) was by far the most successful. For example, that story was featured on the front page of the Washington Post -- perhaps the first time Chandra or X-ray astronomy has garnered such attention. In addition to the Washington Post, the story was covered by the New York Times (a separate picture and editorial), USA Today, NPR ("All Things Considered" and "Science Friday"), The Economist, Time, Newsweek, Voice of America, Seed Magazine, PhysicsWeb, Chemical & Engineering News, Science News, Minneapolis Star Tribune, Boston Globe, CNN International, Space.com, Sydney Morning Herald, BBC News, San Jose Mercury News, Houston Chronicle, Advertiser Adelaide (Australia), Daily Telegraph (Australia), Independent Online (South Africa), Malaysia Star, Hindustan Times, Scientific American.com, USA Today, Register (UK), People's Daily Online (China), Seattle Post Intelligencer, San Francisco Chronicle, Fox News, CBS News.com, CTV.ca (Canada), BBC News.com, National Geographic.com, Globe and Mail (Canada), MSNBC.com, Mumbai Mirror (India), Aljazeera.net, Reuters, News24 (South Africa), The Australian, Seattle Times, Scotsman, ABC News.com, Detroit Free Press, Xinhua (China), New Scientist Space.com, Fort Wayne Journal Gazette (Indiana), PhysOrg.com, Pioneer Press (Minn.), Grand Forks Herald (North Dakota), Columbus Ledger-Enquirer (Georgia), Biloxi Sun Herald, San Luis Obispo Tribune (Calif.), Contra Costa Times (Calif.), The Benton Crier (Iowa), Times of Oman, Science Now, Indianapolis Star, Newsday (NY), Discovery Channel.com, Nature.com, Montreal Gazette, The Columbus Dispatch (Ohio), Aviation Week & Space Technology.

In addition to the press releases listed below, 28 new Chandra images were posted to the chandra.harvard.edu website. Many of these have been picked up various science or astronomy-oriented websites. For the full list of Chandra images from this period, see http://chandra.harvard.edu/photo/chronological.html

Swift is branching out. After major news stories in 2005 about GRBs, Swift is gaining attention for ABGB news like comet and supernova observations. The BBC covered the Swift analysis of the Comet Tempel 1 impact in April. By May, Swift was observing 73P/Schwassmann-Wachmann 3, which received coverage on Space.Com and other websites. The February 18 burst ultimately led to four Nature papers in August about what turned out to be a supernova "caught in the act." A NASA-led telecon attempted to lasso all the results into a cohesive story, and this led to broad coverage in newspapers such as the New York Times, Washington Post and all that Reuters produced, in magazines, and on websites worldwide such as BBC and CNN.

Stefan Immler's HEAD press conference on supernova "mugshots" (October) led to respectable coverage on the web, a full-page article in Science, and a lengthy article in Der Speigel so far. The HEAD press conferences on Swift's black hole census and jets received considerable web coverage from Space.Com, Discovery Channel and elsewhere, as well as articles in USA Today, Washington Times, Christian Science Monitor, Science and Science News. The Reeves-Fabian Suzaku HEAD press conference also made Science and USA Today. Coverage from the HEAD meeting also included a release on M87 (Bill Forman et al.) that was reported in USA Today, Science Daily, Xinhua (China) and Space.com.

Hot from the press: Some pictures of the HEAD meeting are available at: http://lheawww.gsfc.nasa.gov/users/imh/HEAD2006/ and http://www.rxollc.com/windt/photos/20061006_SF/

Please send Ilana Harrus pictures of the meeting you would like to see posted.

PBS aired the NOVA program "Monster of the Milky Way" about Sag A* on October 31. This was a major team effort supported by the National Science Foundation and the Gamma Ray Large Area Space Telescope, with considerable legwork by Sonoma State University. The BBC World Service visited NASA Goddard twice for separate programs on cosmology and high-energy astronomy. This led to two 3-part radio programs by different producers that featured high-energy astronomy prominently. Korea Public Television also visited NASA Goddard for a two-part program on Einstein, naturally featuring HEAD science.

And last but certainly not least! John Mather and George Smoot won the 2006 Nobel Prize in Physics for their COBE work in the 1990s. While not HEAD per se, this recognition of cosmological and astrophysics research will raise the profile of HEAD science. Naturally, this was the biggest astrophysics story of the year, with over 500 Google news hits at one point in mid-October.

5. Chandra X-ray Observatory Operations Report-- Roger Brissenden, Smithsonian Astrophysical Observatory and Martin Weisskopf, Marshall Space Flight Center

Chandra's excellent spacecraft and science instrument performance continued during the last six months. The mission passed its 7 year milestone on July 23 and retains significant reserves of consumables. There were no major anomalies or safemodes during the period, the last safe mode being 6.3 years ago.

The average observing efficiency since May was 67% compared with a maximum possible of ~70%, up from 63% during the prior 6 months. The increase is in large part due to the relaxation of a thermal constraint associated with the EPHIN (Electron Proton Helium Instrument) radiation detector. As discussed in the last report, the maximum allowed temperature limit was raised from 96 deg F to 110 deg F in December and, as expected, has provided much welcome relief to the mission planning team.

Two flight software patches were uplinked in July to add on-board monitoring of selected propulsion line and valve temperatures. The patches added a new monitor and replaced 21 of the Liquid Apogee Engine temperature readings (unused since the ascent phase of the mission with 21 -Z side propulsion line and valve temperatures. Chandra has experienced decreased thermal margins as the mission has proceeded and the new on-board monitor mitigates the risk of a frozen propulsion line by ensuring a transition to normal sun mode in the event that temperatures fall below a safe trigger threshold.

In other operational highlights, Chandra completed the 2006 summer eclipse season in July with nominal power and thermal performance. Chandra also passed though two lunar eclipses without incident, a penumbral eclipse in August and a full eclipse lasting 20 minutes in October. The aspect camera continued its excellent performance, with dark current measurements indicating a continued expected trend in increase of the number of warm pixels. There were no interruptions to the mission schedule due to high solar activity and the schedule was replanned five times to accommodate fast turn-around Target of Opportunity (TOO) observations, with response times ranging from 1 to 3 days.

Both the ACIS and HRC focal plane instruments have continued to operate well.

A test was conducted in August of the HRC +Y shutter select function. During the test, three select/de-select cycles were run and confirmed full functionality of the relay. The test verified that after two years without use the +Y shutter has not been impacted by the same failure mode as the -Y shutter. The -Y shutter did not insert during an attempted observation in 2004, due a failed motor-select relay.

As a result of increasing thermal trends associated with the ACIS electronics, the ACIS team has recommended having the option of selecting the minimum number of chips for a given observation in order to reduce the instrument temperature. A reduction in temperature of 2.5 deg F is expected for each chip powered down.

The Charge Transfer Inefficiency (CTI) of the ACIS Front Illuminated CCD has continued to increase at the expected rate of 2.3% per year and the trend for the Back Illuminated CCD has continued at the expected rate of 0.5% per year. Careful monitoring of the contamination buildup on the Optical Blocking Filer indicates that the transmission at 0.7 keV has decreased by the expected ~1.0% over the last year. No actions are required in response to these trends. In addition, the ACIS team completed the implementation of more accurate on-board energy filters, and of a serial CTI correction.

The processing, archiving and distribution of Chandra data has continued smoothly, and the average time from target observation to data distribution has been maintained at approximately one day. The archive has grown more rapidly in recent months due to the third full reprocessing of Chandra data, and is now 5.3 TB in size. Data retrievals have also increased from ~300 GB to 430 GB per month. The third reprocessing is proceeding well and is now 60% complete with completion expected in spring 2007.

The Operations Control Center ground team completed the development and installation of a patch release (version 11.5.3) and a major release (version 11.6) of the planning and scheduling system (Off-Line System). The new releases fix a number of problems, upgrade capabilities, particularly for plotting and parameter handling, and provide new functionality for scheduling moving objects and handling radiation events. The ground team also completed the installation and testing of a new voice system.

The Science Data System team released versions 7.6.8 and 7.6.9 of the CXC Data System to perform a software infrastructure upgrade, and to provide functionality in support of selectively powering the ACIS chips.

The Chandra Press Office issued 8 press releases and 21 image releases since May, including NASA media telecons in June and August. One media telecon described observations of the galactic black hole system GRO J1655-40 that provide insight into the key role magnetic fields play in the energy release mechanism. The second discussed observations of the galaxy cluster 1E 0657-56 that provide direct evidence for dark matter.

The Cycle 8 peer review was held in Boston in June and selected 184 proposals from 724 submitted for what will be an exciting and high quality science program for the next year. This year, 9 proposals were approved via joint facilities. The 2006 Chandra Fellows Symposium was held at CfA in October and showcased the varied and cutting edge research being conducted by the present Fellows. The Cycle 10 call for Fellows will be made November 2. The CXC co-sponsored the successful Joint Observatories Workshop held in Pasadena in May and will host the Extragalactic Surveys workshop, November 6-8 (for details see http://cxc.harvard.edu/xsurveys06/

We look forward to continued outstanding science from Chandra as we progress into the 8th year of scientific operations.

The Chandra Postdoctoral Fellowship Program -- Nancy Remage Evans -- -- (CfA)

During the fall, the Chandra Fellowship program has two main activities, the Chandra Fellows Symposium and the competition for the Fellows for 2007.

--The Chandra Fellows Symposium was held at Harvard-Smithsonian Center for Astrophysics on October 13, 2006. All the current Fellows gave summaries of their work, which provide a very exciting look on Chandra science. Keep this event in mind for future years. It is open to all interested people. The program for this year is shown below.

--The Chandra Fellowship competition for 2007 closed Nov. 2, 2006. The new group of Fellows will be announced in February, 2007. Details of the next competition will be posted at: http://cxc.harvard.edu/fellows/ in the summer of 2007.


October 13, 2006

Phillips Auditorium, Harvard-Smithsonian Center for Astrophysics

9:00 - 9:20 Welcome

9:20 - 9:40 Jan-Uwe Ness The 6th Outburst of the Recurrent Nova RS Oph in X-rays

9:40 - 10:00 Masahiro Tsujimoto Joint Chandra and Suzaku Spectroscopy of the Arches cluster

10:00 - 10:20 Carlos Badenes Opening a New Window onto the Physics of Type Ia Supernovae

10:20 - 10:40 Franz Bauer Did We Miss a Local Supernova?

11:00 - 11:20 Shane Davis Probing Accretion and Spacetime with Spectra of Black Hole Binaries

11:20 - 11:40 Elena Gallo Jets from Quiescent Stellar Mass Black Holes

11:40 - 12:00 Jifeng Liu Understanding the Nature of Ultra-Luminous X-ray Sources

12:00 - 12:20 Elena Rossi Vertical Nuclear Profile of Hyper-accreting Disks

2:00 - 2:40 p.m. William Forman Shocks, Bubbles, and Filaments: the Interaction of Supermassive Black Holes with Cluster Environments

2:40 - 3:00 Weiqun Zhang Numerical Studies of GRB Afterglows

3:00 - 3:20 Doron Chelouche The Gaseous Halos of Galaxies and Quasars

3:40 - 4:00 Elena Rasia Observing Galaxy Cluster Simulations with an X-ray Telescope

4:00 - 4:20 Benjamin Maughan Chandra Observations of the Galaxy Cluster Scaling Relations

4:20 - 4:40 David Sand Galaxy Cluster Supernovae at 0.1 < Z < 0.2

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6. XMM-Newton Mission News - Randall Smith (NASA/GSFC) and Phil Plait (Sonoma State)

The satellite and all instruments remain in good health, and the operations team is maintaining a high observing efficiency with ~73% of available time used for science observations. A major new release (7.0.0) of the Science Analysis Software was released on June 30th, 2006, which includes a significant calibration improvements for all instruments and is recommended for all users.

XMM-Newton closed its sixth Announcement of Opportunity on October 6th, 2006. A total of 594 proposals were received from 425 different investigators, for a total over-subscription factor of 6.9. We encourage investigators interested in extremely long or otherwise unusual proposals to consider attending the XMM-Newton Legacy Projects Workshop will be held June 4-6, 2007 at the XMM-Newton Science Observations Center near Madrid, Spain. The goal of the workshop is to identify the leading scientific and technical opportunities for legacy projects of XMM-Newton, while may require large amounts of observing time on one or more targets. For more information, see http://xmm.vilspa.esa.es/external/xmm_science/workshops/2007_science/

Recent accomplishments include two notable results on supernova remnants. Jacco Vink (University of Utrecht) and collaborators published an analysis of XMM-Newton and Chandra observations of RCW 86, showing that it is likely the same supernova seen by Chinese astronomers in 185 AD. Meanwhile, Andrea De Luca (IASF/INAF) and collaborators discovered that the central neutron star in RCW103 (1E16348-5055) exhibits an curiously long 6.7 hour period. If this is an orbital period, the system is perhaps the youngest low-mass X-ray binary known (the remnant is only 2000 years old) while if the period is due to rotation it would require some never-before-seen method to slow the spin of the young neutron star.

For more information about XMM-Newton, please visit the US Guest Observer Facility pages at http://heasarc.gsfc.nasa.gov/docs/xmm/xmmgof.html

XMM-Newton E/PO News:

The XMM-Newton E/PO group has created the Supernovas Educators Guide with additional support from GLAST. This guide has three activities which reflect different aspects of a supernova. The guide also includes an introduction to the history of supernova astronomy and why stars explode, and a beautifully illustrated poster with an artist's conception of a supernova as seen in visible, X-rays, and gamma rays, as well as a timeline illustrating a supernova remnant's evolution. This guide is currently undergoing testing, with aspects presented at two different workshops.

The XMM-Newton E/PO group sponsors Space Place to write articles about XMM science. They recently published two articles written by Dr. Tony Phillips: "Brush your teeth and avoid black holes?" about how astronomers observe X-rays and "Not a Moment Wasted" about XMM-Newton's slew survey. The first was sent to newspapers, and the second as part of a newsletter sent to astronomy clubs.

The SSU E/PO group has also begun working with the Astronomical Society of the Pacific's (ASP) Night Sky Network to create a kit containing a series of activities based on high-energy astronomy. GLAST and Swift are sponsoring this along with XMM-Newton, as well as Suzaku. The SSU staff, with Jim Lochner, Beth Barbier, and Sara Mitchell from the GSFC-based Suzaku E/PO team, met with NSN personnel at the annual ASP meeting to go over possible topics for the new kit.

Since April 2006 (the last newsletter), XMM-Newton Educator Ambassadors and E/PO professionals disseminated educational materials and XMM-Newton content at five different workshops, reaching 178 participants.

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7. INTEGRAL News - Christoph Winkler

INTEGRAL is continuing to work smoothly and to produce interesting results. The space-craft and the instruments function well and the ground segment operates routinely. The publication rate keeps increasing with more than 196 papers published in refereed journals up to the end of June 2006.

The 4th Announcement of Opportunity (AO-4) for INTEGRAL observations was very successful with an over-subscription factor of 8 and a 31% increase in the number of proposals compared to AO-3, largely due to the inclusion of a prototype Key Programme on the Galactic Centre region. At the time of writing the first observations of AO-4 have been done, including already the first TOO (EXO 2030+375)!

From July 2 to 8 more than 200 participants from European countries, the USA, Russia and Japan enjoyed a lively workshop and the hos-pitality of our Russian colleagues at the Space Research Institute (IKI) in Moscow. The theme this time was "The Obscured Universe". The workshop was jointly co-sponsored by IKI (Space Research Insti-tute), ESA (European Space Agency), RAS (Russian Academy of Sciences) and RFBR (Russian Foundation for Basic Research).

For more INTEGRAL news, please see the INTEGRAL Newsletters at http://integral.esac.esa.int//newsletters/

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8. RHESSI Mission News - David M. Smith, U. C. Santa Cruz

The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) continues to observe flares and microflares from the Sun even in the current solar minimum. Although the rear segments of its germanium detectors are suffering badly from radiation damage, the front segments continue to have excellent resolution at low energies (below 100 keV), and the entire detectors can still be used for continuum work. Annealing of the detectors to improve energy resolution will take place before the next solar maximum, but is not scheduled for the near future due to the excellent continuing performance of the front segments.

RHESSI has been functioning as part of the Interplanetary Network to localize cosmic gamma-ray bursts (GRBs) for some time now, in an effort led by Kevin Hurley of the University of California, Berkeley (UCB). Recently, a larger team at the Paul Scherrer Institute (Switzerland) and UCB has begun providing spectral fits to GRBs from RHESSI within a few days of discovery, via the GCN circulars (Eric Bellm et al., GCN 5418, 5685; Claudia Wigger et al., GCN 5725). RHESSI can sometimes get a better value for the peak energy "Epeak" of the GRB than other instruments, particularly for harder bursts (high Epeak). Finding Epeak for a large sample of GRBs is useful both for the modeling of GRB physics and for the effort to use GRBs as a standard candle for cosmology.

Another successful offpointing campaign to the Crab Nebula took place this June. We are also taking advantage of long periods with very low solar activity to study the x-ray spectrum of the quiet Sun. Assuming that the source is comparable in size to the solar disk, this can be done by letting the Sun drift to the edge of the instrument's field of view (about 1 degree off axis). In contrast to RHESSI's usual bi-grid collimator imaging, which creates many rapid modulations per spacecraft spin period, the offpointing lets each grid operate as a simple rotating slat collimator, modulating the entire Sun twice per spin. Little is known about what to expect from the quiet Sun: there may be contributions from very low-level particle acceleration in the corona, and there is certainly occultation of the cosmic diffuse background (a negative contribution) and some x-rays related to cosmic rays hitting the Sun (a positive contribution). The solar disk is also a place to look for exotic, long-shot physics like axion annihilation. You can read about this work, led by Dr. Iain Hannah of UCB, at the following website: http://sprg.ssl.berkeley.edu/~tohban/nuggets/?page=article&article_id=16

Other RHESSI science "nuggets" suitable for a general scientific audience can also be found there. Solar physics preprints, including many from RHESSI, are available at: http://solar.physics.montana.edu/cgi-bin/eprint/default_page.pl RHESSI results will be presented in several sessions of the 2006 Fall meeting of the American Geophysical Union in San Francisco.

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9. Swift Mission News - Padi Boyd and Neil Gehrels (GSFC) and Phil Plait and Lynn Cominsky (Sonoma State)

As of mid-October 2006, Swift has observed 185 gamma-ray bursts (GRBs) and performed 177 rapid-reaction targets of opportunity for non-burst transients. The instrument continues operating in good health.

Swift also continues to monitor the early light curves of nearby supernovae, particularly in the UV, to investigate the existence of a UV canonical light curve and search for early X-ray emission from the events.

The BAT team has made light curves from their survey processing available at http://swift.gsfc.nasa.gov/docs/swift/results/transients/ The light curves cover the time range September 2005 through the present and are updated when new data are received from the spacecraft. Data for well over 200 persistent and transient high energy sources are available.

The Swift team has recently begun to compile short reports on BAT, XRT and UVOT observations of GRBs. They can be found at http://gcn.gsfc.nasa.gov/report_archive.html These reports summarize the basic information from each instrument (position, duration, fluxes, etc.) and include light curves from all three instruments.

The Swift Cycle 3 proposal review was held in San Francisco in early October 2006. Scientists from around the world met to evaluate the 88 proposals submitted for funding and/or observing time. A new component to Cycle 3 was limited Target Of Opportunity proposals. This was the most popular component of the GI Program, and a well-balanced program has been accepted. The results of the Swift review should be communicated to PIs by NASA Headquarters in the near future.

Look for information on Swift Cycle 4 to appear in the NASA Research Opportunities in Space and Earth and Sciences (ROSES)-2007, due to become public in late January 2007.

Swift E/PO News: The E/PO group has published the fifth quarterly newsletter, designed to keep scientists and the public updated on the latest Swift news. The newsletter opens with a note from PI Neil Gehrels, and has updates on Swift science and educational products, as well as links to news articles featuring Swift. The newsletter and archives are online (in both HTML and PDF) at http://swift.sonoma.edu/resources/multimedia/newsletter/index.html

The real-time all-sky GRB ( http://grb.sonoma.edu) page has had about 60,000 unique visits since April 2006. The page displays all the GRBs detected by Swift, INTEGRAL, and other gamma-ray satellites as they send out notices to the Gamma-Ray Coordinates Network. In addition, we have created the "GRB Lottery," where people can guess where the next GRB will occur. The site -- http://swift.sonoma.edu/grb_lotto/ -- was created by Swift E/PO team member Tim Graves, and has a very appealing and fun interface.

The Swift E/PO group has updated the very popular Newton's Laws posters. These posters, designed to illustrate the Three Laws of Motion, went through thorough testing recently, and were improved using those tests as guidelines. We also added a fourth poster, covering the Universal Law of Gravitation. We are awaiting the final assessment and professional overview of the posters from WestEd, our external evaluators, before we can go through the final revision and print the posters.

Swift information and E/PO goodies were distributed at the GLAST exhibit booth which was sent to the October HEAD meeting in San Francisco. E/PO staff Phil Plait and Sarah Silva also recorded interviews with several GLAST and Swift team members which will be edited and added to the websites as a semi-regular feature. We hope that this will bring some of the excitement and human interest of these missions to classrooms and the public.

Prof. Lynn Cominsky helped prepare two Swift press releases, which were featured in press conferences at the HEAD meeting, in San Francisco in October (see HEAD in the News for more information). A NASA telecon about GRB060218 was held in August, with evidence from Swift that a supernova was "caught in the act." Another press release from Swift, featuring x-rays detected from a comet, also made news in May. The planetarium show "Black Holes: The Other Side of Infinity," which features the Swift launch, is now playing at several venues across the country. And the PBS NOVA show "Monster of the Milky Way" includes footage of the Swift Mission Operations Center at Penn State. (See the GLAST E/PO entry for more details about both of these shows.)

Since May 2006 (the last HEAD newsletter), Swift Educator Ambassadors and E/PO professionals disseminated educational materials and Swift content at 15 different workshops, reaching 2836 participants.

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10. RXTE News - Padi Boyd, Keith Jahoda, Craig Markwardt, Gail Rohrbach, Evan Smith, Tod Strohmayer, and Jean Swank - GSFC

The Rossi X-Ray Timing Explorer (RXTE) has now passed its first decade in orbit. RXTE continues to serve the astrophysics community, and to produce important scientific results, some of the most recent of which are highlighted below. RXTE's Cycle 11 observing program is currently well underway.

NASA's 2006 Senior Review of the Astrophysics Division Mission Operations and Data Analysis (MO&DA) Programs was held in April 2006. The panel found that "RXTE remains a valuable asset to NASA's space science mission set. It continues to be productive, with continuing substantial interest from the community." We are pleased to report that the review panel recommended continuing RXTE operations until February 2009. As a result of this late-breaking good news about RXTE's future, an Announcement was released by NASA Headquarters in late October, 2006, soliciting proposals for observations to be carried out beginning about June 1, 2007. We would like to thank all RXTE users and friends whose science results helped us make a strong case for continuing the mission.

The Cycle 12 Announcement solicits proposals for observations only. There is no Guest Observer funding to analyze Cycle 12 observations, however, observers with proposals accepted through the Cycle 12 Announcement may submit funding proposals to the NASA Astrophysics Data Program (ADP).

The Cycle 12 proposal due date is Friday, January 26, 2007. The peer review will be held in the Baltimore area in early April 2007. Please consider offering your services as a Peer Reviewer. Interested Ph.D. scientists can be added to the reviewer pool by sending an email to peer_review@olegacy.gsfc.nasa.gov. Since this may well be the last call for RXTE proposals, we encourage all members of the HEAD community to consider submitting an RXTE Cycle 12 observing proposal.

The policy of the RXTE guest observer program has been to complete accepted observations to the best extent possible. Targets of opportunity have often led to delay in carrying out other observations that were not time critical. We hope that 2007 will be an opportunity to successfully schedule some of these delayed observations. Details of how to handle extension of monitoring programs and target of opportunity proposals soon will be posted on the RXTE web site at http://xte.gsfc.nasa.gov/docs/xte/xte_1st.html.

Science Highlights:

In one of the more imaginative uses of RXTE data that has ever come to our attention, Hsiang-Kuang Chang (National Tsing Hua University, Taiwan) and colleagues have discovered millisecond long dips in the X-ray flux from Sco X-1 using RXTE's proportional counter array (PCA). They found about 50 of these dips, each lasting several milliseconds, in 320 ksecs of data on the source. They argue that the dips are most likely produced by occultations of Sco X-1 by small (< 100 meters) trans-neptunian objects (TNOs) within our solar system. Detecting such dips requires a high counting rate, hence their use of Sco X-1 for this study. They suggest that the number of observed dips is more or less consistent with an extrapolation of the size distribution based on direct observations of larger objects. Details of their study can be found in Nature, 442, 660-663 (10 August 2006).

Observations of Supernova 1987A with RXTE have not yet found a pulsar in its remnant, but John Middleditch (LANL), Frank Marshall (NASA/GSFC) and colleagues did locate another nearby pulsar, PSR J0537-6910, that is still the fastest known rotation powered pulsar (16 ms spin period). This pulsar is also the most prolific "glitcher" known, and seven years of RXTE monitoring of the pulsar have yielded some amazing findings. A total of 23 glitches have now been seen, and a clear correlation has been found between the strength (amplitude) of a glitch, and the time interval to the next glitch, such that after a big glitch there is a longer waiting time to the next glitch. The correlation is good enough that the date the next glitch will happen can be predicted with an accuracy of a few days. The data suggest that there is a maximum lag that can develop between the rotating crust and its superfluid component. Details will appear in the Astrophysical Journal, but presently can be found at http://xxx.lanl.gov/abs/astro-ph/0605007

A pair of interesting results on accreting millisecond pulsars were presented as side-by-side posters by Fotis Gavriil (NPP/GSFC) and Miriam Krauss (MIT) at the recent HEAD meeting in San Francisco. Gavriil and collaborators reported the discovery of a new, but intermittent 442 Hz pulsar during RXTE observations of the Globular Cluster NGC 6440. Pulsations were observed only once, for about 500 seconds following a drop in the X-ray flux which may have been the decaying tail of an X-ray burst, or perhaps the precursor of a "superburst." A small downward drift in the coherent pulsation was also detected, but the pulsation died away before the end of the observation. Krauss and colleagues reported on RXTE observations of HETE J1900.1-2455, the 377 Hz accreting pulsar. They have found that, unlike other accreting millisecond pulsars, the source has remained active for more than a year, and, interestingly, the pulsations are detected only intermittently, with abrupt increases in the pulsed amplitude following thermonuclear bursts. The behavior of these two objects may be related, and they could provide new insight as to why the majority of accreting neutron star LMXBs do not show persistent pulsations.

A number of accreting binary systems have been observed in outburst. In June 2006 the Be/X-ray pulsar EXO 2030+375 started a large outburst (type II) and reached a peak luminosity about 70% of that seen with EXOSAT during the discovery outburst (Atels 843, 877). A joint spectral analysis with PCA and HEXTE data required a Gaussian absorption line at 10.1 keV, which can be ascribed to cyclotron resonance absorption. Colleen Wilson-Hodge and Mark Finger (NSSTC) also reported that strong spin-up was observed.

RXTE GOF Update:

New background models for RXTE PCA observations were recently made available to the public. The new models have removed long term trends that became apparent over the years (with magnitudes of ~0.2 ct/s/PCU). Only models for "Epoch 5" -- May 2000 to the present -- were changed.

The unmodeled variance in the background rate, which fundamentally limits the sensitivity to source variations, is 0.04 ct/s/PCU or better, in the top layer 2-10 keV band, and 0.02 ct/s/PCU in the top layer 10-20 keV band. However, for purposes of determining absolute fluxes of sources at arbitrary points on the sky, the cosmic X-ray background is the limiting factor. The new background models can be downloaded from the "PCA Digest page." http://heasarc.gsfc.nasa.gov/docs/xte/pca_news.html

Earlier this year, HEXTE cluster A experienced more periods where on- and off-source modulation (ie. rocking) ceased. Because of this the decision was made to permanently leave HEXTE Cluster A in the on-source position, rather than risk it becoming unrecoverable in an off-source position. The detectors in cluster A are still functioning well; HEXTE cluster B also still modulates as normal, and shows no sign of impairment. The HEXTE team has delivered new software that will allow users to generate cluster A background estimates from simultaneous cluster B background files (see Katja Pottschmidt's HEAD poster about hextebackest at http://heasarc.gsfc.nasa.gov/docs/xte/whatsnew/hextebackest_poster.pdf).

The RXTE GOF is now working to make this code available at the next interim HEAsoft (FTOOLS) release, currently scheduled for late November. Before analyzing any HEXTE A data taken in 2006, we recommend users consult the RXTE "Significant Events" page (http://heasarc.gsfc.nasa.gov/docs/xte/whatsnew/big.html) to see whether HEXTE A was fixed or rocking when their data was collected. When the HEAsoft release containing the new HEXTE tool is available, an announcement will be sent to the XTENEWS mailing list, and will also appear on the RXTE homepage ( http://heasarc.gsfc.nasa.gov/docs/xte/xte_1st.html).

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11. Suzaku News - Koji Mukai and Ilana Harrus (GSFC)

Suzaku Cycle 2 proposals are due on December 1, 2006 at ISAS/JAXA, NASA/GSFC, or ESA, depending on the country in which the principal investigator resides. US-based HEAD members are invited to visit the Suzaku GOF page ( http://suzaku.gsfc.nasa.gov/ ) for further details.

ISAS/JAXA and NASA/GSFC have begun distribution of processed guest observer (GO) data. Initial processing pipeline version 1.1; an improved version (1.2) is now in place. We plan to reprocess all data, including the Science Working Group (SWG) observations, using v1.2 pipeline. In a related note, NASA has started distribution of Suzaku grants for successful Cycle 1 proposers whose observations have already been performed.

Both the XIS and the HXD continue to function well. The XIS team has begun the use of "spaced-row Charge Injection" (CI). In-orbit radiation damage has led to increasing charge transfer inefficiency (CTI), which degrades the spectral resolution of the CCDs. Spaced-row CI fills the charge traps with injected charge, thereby dramatically reducing the CTI. With CI, the spectral resolution in the Fe K band recovers almost to the immediate post-launch level. The XIS team has begun to offer CI as an option to Cycle 1 GOs; this will be the default for Cycle 2 observations.

Members of the Suzaku SWG have been busy analyzing the early data, from which 2 refereed papers have already appeared in ApJ Letters (Murashima et al. 2006, ApJ 647, 131L and Terada et al. 2006, ApJ 648, 139L). A special issue of Publications of the Astronomical Society of Japan is in press, containing 30 papers (including the spacecraft and instrument papers). The issue should have a 2006 publication date; in the mean time, many of these papers have already appeared on astro-ph. At the recent HEAD meeting, there were several presentations featuring Suzaku data. In addition, ISAS/JAXA prepared a CD-ROM containing the ApJ and PASJ papers; all 100 copies were "sold out" within the first couple of days of the meeting.

Reminder: Suzaku Cycle 2 observing proposals are due on Dec 1, 2006.

The AO-2 version of the Suzaku Technical Description document is now online. Response files for simulation and related tools have also been updated for AO-2 proposers.

Please note that, although a version of the Technical Description document was made available on Oct 28, some important XIS updates were inadvertently left off at the time. Please refer to the new version (GSFC version was updated Monday afternoon; ISAS version Tuesday morning). Please see http://suzaku.gsfc.nasa.gov/docs/suzaku/aehp_prop_tools.html

Suzaku EPO News:

The Suzaku EPO team is on its way to Hollywood! Well, maybe not that far, but still. The team received the 2006 Silver Telly Award for the video called "Building the Coolest X-ray Satellite" telling the story of the building of the XRT and XRS on-board Suzaku. If you don't have your very own copy, ask for it at your local video store or at: http://suzaku-epo.gsfc.nasa.gov/cgi-bin/astroe_lc/order.pl

Encouraged by the result of their first foray in the "Seventh Art", the team is preparing another video on spectroscopy and music. Production is very hush-hush but the schedule calls for a release in time for the Oscar ceremony.

We are also currently planning a Night Sky Network kit in collaboration with Sarah Silva, Lynn Cominsky, Phil Plait, and Logan Hill at Sonoma State University and the Astronomical Society of the Pacific. The kit, featuring activities conceived for the amateur astronomer community, will be ready for release early 2008.

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12. GLAST Mission News - Christopher Wanjek, Steven Ritz and Phil Plait

All the major components of GLAST are now at General Dynamics C4 Systems (Spectrum Astro) in Scottsdale, Ariz., undergoing final assembly. The GLAST Burst Monitor arrived in July, after successful environmental testing at Marshall Space Flight Center. The Large Area Telescope (LAT) arrived in September. In May, LAT had shipped from SLAC to the U.S. Naval Research Laboratory in Washington for environmental testing, which was completed on schedule. From NRL, LAT was trucked back across the country to Arizona. After both instruments are integrated onto the spacecraft, GLAST will travel back east once again, to the NASA Kennedy Space Center for launch in fall 2007. A beam test of LAT hardware was completed at CERN in September.

The very successful GLAST Data Challenge II ran from March to early June. As reported in the previous HEAD news, the goal of this game was to detect the gamma-ray sources planted in simulated data that look very much like what is expected to be seen once GLAST is in orbit. More than 100 scientists participated, and the closeout meeting, where the "truth" was revealed, was held at Goddard. Data challenges are becoming common practice for large particle physics experiments; they are new to astrophysics experiments, but beneficial for any mission to test data processing and analysis software end-to-end before launch. The GLAST Users Committee will do a beta test of the analysis tools in November.

The First International GLAST Symposium will be held on 5-8 February 2007 at Stanford. Please visit the conference website at http://glast.gsfc.nasa.gov/science/symposium/2007/ and register.

We are starting a monthly GLAST news email list. To sign up, please send an email to majordomo@athena.gsfc.nasa.gov (you can leave the subject line blank); in the body of the message, please write the following: subscribe glastnews your-email-address

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13. Constellation X Mission Update - Michael Garcia for the Con-X Team

In our last newsletter article, we mentioned that the FY07 budget was difficult for all of the NASA Science Mission Directorate, ConX included. Several projects were canceled outright. ConX did well in comparison by suffering only a 50% budget cut just mid-way through the fiscal year, but in the words of the 2007 budget request was 'deferred indefinitely' The entire Beyond Einstein program suffered similarly difficult cuts and delays. Simply delaying a mission increases its cost due to inflation, and multi-year delays can result in substantial increases in projected costs.

In this climate, it was clear that the ConX team would do well to continue to look into ways to reduce the cost of the mission. Having recently moved from a 4 spacecraft configuration utilizing 2 Atlas V launchers to a single spacecraft utilizing a single Delta IV Heavy launcher and thereby saving $180M, we investigated even less expensive launch options.

We found that we could fit 4 (somewhat smaller) Spectroscopy X-ray Telescopes into a single Atlas V. To maintain effective area and to lift the payload to L2 on the single Atlas V required removing the 12 Hard X-ray Telescopes and the Reflection Grating Spectrometer. The resulting configuration reduces costs by $700M, meets the effective area requirements at our reference energies of 0.25, 1.25, and 6 keV and has reasonable effective area out to ~15keV. In order to retain all of the key science objectives as outlined in the last Decadal and detailed on the Con-X web site, this configuration includes a Science Enhancement Package (SEP) which will increase the spectral resolution at low energies and/or the effective area at high energies. The details of the SEP are currently being worked. A Request for Information about SEP options was released on Oct 17 2006.

Details of this new 'Atlas V Configuration' were presented at the recent HEAD meeting in San Francisco. This was the largest HEAD meeting ever, and the Constellation-X talks were very well attended. You can find the talks by Harvey Tananbaum, Ann Hornschemeier, and Nick White on the Con-X home page (right hand column) at http://constellation.gsfc.nasa.gov/.

In parallel with the definition of the SEP, the Constellation-X team is preparing for a review which NASA and DOE have asked the National Research Council(NRC) to undertake. The NRC will review the 5 Beyond Einstein(BE) missions and recommend which should go first. This review will also provide input which NASA could use for future decisions regarding the support and sequencing of the other BE missions pending inputs from the next Decadal Survey.

Inputs to this review are expected to be provided soon, no later than Jan 2007. Your help in preparing for this review is invited! Several teams are already working on updates to the science case. These teams are loosely based on those which helped produce the May 2005 'Science with Constellation-X' Booklet, and many of them met at the recent HEAD meeting. If you wish to contribute please contact Michael Garcia or Ann Hornschemeier.

There will be an open meeting of the Constellation-X Facility Science Team (FST) from Dec 18-20 at GSFC. The agenda for this meeting will include discussion of the SEP, the Atlas V configuration, and the science case to be presented to the NRC Review Committee. You are invited to attend, but please be advised that the meeting will take place on the GSFC base and therefore ID Badges will be needed. For details see the Constellation-X home page, and keep in mind that the deadline for requesting badges is Dec 11 for US citizens and more than 1 month earlier for non-US citizens.

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14. LISA Mission Update - Bonny Schumaker, JPL

LISA is a unique facility for astronomy and physics that will open a huge discovery space unreachable from ground and untapped by other space missions. It will detect and measure the properties of gravitational waves over a broad band at low frequencies, from 0.1-100 milliHz. This will offer the opportunity to study a wide range of sources that are "dark" electromagnetically: massive black holes merging in galaxies at all distances; massive black holes consuming smaller compact objects; non-interacting binary compact stars and stellar remnants; and other less predictable sources such as relics of the extremely early big bang. Many LISA sources will also have electromagnetic counterparts, at a variety of timescales and measurement frequencies. For example, known optical binaries will be used to verify LISA's operation during initial on-orbit commissioning; and many other of LISA's white-dwarf binaries will be observable by tidal heating and eclipses. Black hole mergers with accompanying disruption of their innermost accretion disks may display non-thermal radiation from radio to gamma rays; and compact objects falling into larger black holes may radiate electromagnetically as debris is stripped from them.

These signals convey rich information addressing a wide range of science: the history of galaxies and black holes in the universe; General Relativity and the behavior of spacetime; precision measurements of the Universe on a cosmic scale; the physics of dense matter and stellar remnants; and possibly new physics associated with events in the early Universe or relics predicted by string theory.

LISA's science can be summarized briefly by the following goals and their ramifications:

1) Record the inspirals and mergers of binary black holes. This will provide a precise mathematical understanding of the most powerful transformations of energy in the Universe, and a rich testbed for General Relativity.

2) Map isolated black holes with high precision, and verify that they are the stationary "no-hair" spacetimes described by the Kerr metric - i.e., specified completely by their mass and three components of spin. This information will come from black hole mergers and from the "Extreme Mass Ratio Inspirals" (EMRIs) involving compact objects such as degenerate dwarfs, neutron stars, or stellar-mass black holes.

3) Observe directly the formation, growth, and interactions of massive black holes over the entire history of galaxy formation. The Universe accessible to LISA contains so many galaxies in their formation stage that mergers happen quite frequently. Indeed, if the massive black holes inferred to be at the centers of most galaxies formed primarily by this process, LISA will detect a merger event once or twice per week, from a wide range of redshifts extending back to early protogalaxies at z~15.

4) Measure precise, gravitationally-calibrated absolute distances to very high redshift. This will offer a unique contribution to measurement of the Hubble constant and Dark Energy. It is achievable because the inspiral leading to merger of black holes generates gravitational waves that can be computed exactly in General Relativity, so that the masses, spins, orientations, and exact distance can all be reconstructed from the LISA data, over a wide range of redshift. If an electromagnetic counterpart can be identified to provide an independent redshift, then in the absence of propagation effects the absolute physical distance can be estimated to better than 1% precision.

5) Measure the 3D positions and orbital properties of thousands of compact binary stars in our Galaxy. This will provide a new window into matter at the extreme endpoints of stellar evolution, detailed mapping and reconstruction of the history of stars in our Galaxy, and insight into tidal and other non-gravitational influences on orbits that reflect internal physics of the compact remnants. These are among the "guaranteed" LISA sources - some of them, with already-known positions and periods, will be used during on-orbit commissioning to verify LISA?s operation.

Finally, given that all forms of mass and energy couple to gravity and that LISA will probe to very high redshift, we can expect to discover new phenomena not detectable with instruments that measure particles and fields. The LISA band in the relativistic early Universe is the Terascale frontier, where phase transitions of new forces of nature or extra dimensions of space might have caused catastrophic, explosive bubble growth and efficient (>10^-7) radiation of gravitational waves, producing a background visible to LISA between about 100GeV and 1000TeV. LISA will also probe new forms of energy, such as superstrings (relics of the early Universe), visible only by the gravitational waves they emit. Their signature could provide direct evidence that all forms of matter and energy, even spacetime itself, are made of quantum strings.

LISA Mission Overview

LISA uses three identical spacecraft whose relative positions mark the vertices of an equilateral triangle five million km on a side, in orbit around the Sun. It can be thought of as a giant Michelson interferometer in space, with a third arm that provides independent information on the two gravitational wave polarizations as well as redundancy. The spacecraft separation - 5Mkm - sets the LISA measurement band. The centre of the LISA triangle traces an orbit in the ecliptic plane, 1AU from the Sun and 20 degrees behind Earth, and the plane of the triangle is inclined at 60 degrees to the ecliptic (see Figures 1 and 2) . The triangular formation is maintained throughout the year, with the triangle appearing to rotate about its center once per year.

The actual implementation more resembles spacecraft radio Doppler tracking, but with infrared laser light. Laser light received from the distant spacecraft is phase-locked to a local laser and transmitted (transponded) back, where it is combined in a standard heterodyne detection scheme with a portion of the original laser light. The use of two arms is essential for immunity to laser frequency fluctuations. But because orbital mechanics prohibits keeping the arms sufficiently equal in length, LISA uses a two-fold approach to synthesize an equal-arm Michelson. First, each laser is pre-stabilized to an optical cavity, and further stabilized to the LISA arms themselves by a technique called "direct arm-locking." Second, any residual laser frequency noise in the measurements is removed by a processing technique called Time Delay Interferometry (TDI).

Each spacecraft contains a pair of optical assemblies oriented at roughly 60 degrees to each other. Each assembly is pointing toward a similar one on the corresponding distant spacecraft, to form a (non-orthogonal) Michelson interferometer. Through a 40-cm aperture telescope on each assembly, a laser beam from a Nd:YAG master laser and 2-W Yb:YAG fiber amplifier is transmitted to the corresponding remote spacecraft. The same telescope is used to collect the very weak incoming beam (around 100 pW) from the distant spacecraft and direct it to a sensitive photodetector, where it is combined with a local-oscillator beam derived from the original local laser light. At the heart of each assembly is a vacuum enclosure containing a free-flying polished platinum-gold cube, 4 cm in size - the "proof mass," which serves as an inertial reference for the local optical assembly. A passing gravitational wave will produce a relative strain in this large "optical truss" causing an increase in the optical path length between proof masses forming one arm while causing a decrease for the other arm. These length changes are measured interferometrically with sub-Angstrom precision. In this way, LISA will be sensitive enough to detect gravitational-wave induced strains of amplitude h=?l/l ~ 10-23 in one year of observation, with a signal-to-noise ratio of 5.

The spacecraft surrounding each pair of optical assemblies serves primarily to shield the proof masses from the adverse effects of solar radiation pressure fluctuations; the spacecraft positions do not enter directly into the measurements. Nevertheless, in order to minimize disturbances to the proof masses from fluctuating forces in their vicinities, each spacecraft must be kept moderately centered around the proof masses (to about 10 nm/Hz in the measurement band). This is achieved by a "drag-free" control system based on small electric thrusters and displacement sensors. Specifically, both capacitive and optical sensors are used to measure the displacements and rotations of the proof masses relative to the spacecraft. These offset signals are then fed back to control micro-Newton thrusters, which force the spacecraft to follow its proof masses. The thrusters are also used to control the attitude of the spacecraft relative to the incoming optical wavefronts, using signals derived from quadrant photodiodes. Capacitive actuation is used to adjust the positions or orientations of the proof masses when needed.

LISA Programmatics

The LISA Mission is based on a strong partnership between NASA and ESA. Since the formal agreement was signed over two years ago, the two agencies have worked very closely as a single virtual team to develop the technologies and the mission architecture. The formulation phase began formally in January 2005. The Mission Architecture Review took place in October 2005 and Mid-term review this past spring. An independent technology review held last spring concluded that the mission's technology requirements are well understand and the plans for completing development of the critical technologies are sound.

LISA's launch will be preceded by the LISA Path Finder (LPF), a technology demonstration mission managed by ESA which carries both ESA and NASA test packages the LISA Test Package (LTP) and the Disturbance Reduction System (DRS), respectively. These will prove LISA's measurement principle and its key technologies in space. More information at an introductory level can be found in issues of The LISA Newsletter and other links at www.lisa-science.org, the internal web portal for the LISA International Science Community.

Current LISA efforts are focused in three areas: Science capability, Technology maturity, and Total mission cost. The science case for LISA has been developed extensively and continues to grow in depth and clarity. Data analysis methods are being developed to ensure that we will be ready to identify sources (individual and background), including techniques to pull signals out of background noise (including source noise, such as the sea of galactic white-dwarf binaries) and numerical relativity breakthroughs to predict waveforms for the inspiral, merger, and ringdown phases of massive black hole mergers. A strong case is growing to prove that the science proposed by LISA is doable and the science requirements well understood.

As noted above, a recent independent review of technology development program concluded that LISA is well on its way to completing development of the critical technologies. Several key technology efforts are summarized in the first and second issues of The LISA Newsletter.

Mission cost is currently being probed at a new level of granularity, in order to be ready to exercise a price-H-type model to verify credibility of the estimates. This has only been possible as the point design of the architecture has become clearer. A costing tool is under development that will accommodate the various design trade studies that remain. Even science return has begun to be quantified to give formulae for scientific value in terms of factors such as number of resolvable sources we can expect to detect, intrinsic scientific interest of each type of source, and how these relate to mission lifetime. Ultimately, these relations among scientific value, mission life, and instrument sensitivity will be convolved with analogous relations derived by system engineering for mission cost, with the resulting ability to answer questions such as "What mission life time maximizes scientific value per dollar?" These kinds of studies are needed to ensure that the mission design is scalable, allowing cost to be reduced if required, with a clear understanding of the impact on the science return.

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14. Meeting Announcements - a partial list!

Editor's note: A list of international astronomical meetings can be found at http://cadcwww.dao.nrc.ca/meetings/meetings.html

Below are listed meetings that may be of interest to HEAD members, and particularly those where the meeting organizers have asked to have their meeting announcement included in the HEAD newsletter.

"TEXAS IN AUSTRALIA" 23rd Texas Symposium on Relativistic Astrophysics, Melbourne, Australia 11-15 December 2006

for more information, please see www.texas06.com

The First GLAST Symposium, Stanford University, CA, USA 5 -8 February, 2007

This is the first meeting in the series of International GLAST Symposia. The Gamma-ray Large Area Space Telescope, GLAST, is a mission to discover and study cosmic gamma-ray sources in the energy range 20 MeV to >300 GeV, with supporting measurements for gamma-ray bursts from 10 keV to 25 MeV. With its launch in Fall 2007, GLAST will open a new and important window on a wide variety of high-energy phenomena, including black holes and active galactic nuclei; gamma-ray bursts; pulsars; the origin of cosmic rays and their relation to supernova remnants; probes of the optical-UV EBL; new source classes; solar physics; and searches for signals of hypothetical new phenomena such as particle dark matter annihilations, extra dimensions, Lorentz invariance violation, and other relics from the Big Bang. The first Guest Investigator Cycle will start in 2007, with proposals due soon after the Symposium. More information about the mission can be found at http://glast.gsfc.nasa.gov and at links therein. The first Symposium will focus on the new scientific investigations enabled by GLAST, mission and instrument characteristics, analysis tools and opportunities for guest investigators, and coordinated observations and analyses. It is expected that the second Symposium will occur approximately 18 months later.

More information can be found at http://glast.gsfc.nasa.gov/science/symposium/2007/

"Clusters of Galaxies as Cosmological Probes" Winter 2007 Aspen Astrophysics Conference, Aspen, Colorado 12-16 February, 2007 Contact Andrey Kravtsov, e-mail: andrey@oddjob.uchicago.edu

The Aspen Center for Physics website should be consulted for details about Aspen. See http://www.aspenphys.org/

The Next Decade of Gamma-Ray Burst Afterglows -Amsterdam, The Netherlands 19-23 March 2007 Contact Ralph Wijers rwijers@science.uva.nl

Extragalactic Jets: Theory and Observation from Radio to Gamma Rays-- Girdwood, Alaska, USA 21-24 May, 2007

This international meeting is intended to bring theorists and experimentalists together to discuss the nature of extragalactic jets, from parsec to kiloparsec scales. Special emphasis will be given to the interaction of jets with their environment and to the insights this interaction can provide. All wavelengths will be discussed. A major goal of the workshop is to enhance communication and to further collaboration in the field. To facilitate dialog, the conference will be limited in size to 80 participants. More information at http://aftar.uaa.alaska.edu/jets2007/

Obscured AGN across Cosmic Time Kloster Seeon, Bavaria, Germany 5-7 June 2007

Current deep surveys, notably in X-rays and the mid-IR, are making it possible to carry out a census of essentially all the luminous AGN in the universe. By penetrating the obscuration that, in Type II sources, hides the nuclear regions in the UV to the near-IR spectrum, these new surveys are finding the radio quiet counterparts of the powerful radio galaxies.

The completion of such a census has substantial cosmological significance since it will provide the foundation for identifying the role of AGN feedback in the galaxy formation process. The Type II sources are of particular value here since, by acting as their own coronographs, they facilitate the study of the star formation activity and the investigation of the correlated growth of the black hole and the host galaxy.

While radio galaxies - which are being used to trace the massive galaxy population at all epochs - have been studied intensively for the past 40 years, their radio quiet counterparts beyond the local universe are only now being discovered in substantial numbers. The workshop aims to bring together the established radio galaxy community with the students of the radio quiet sources and so help to elucidate the effects of the (possibly) different host galaxies and environment and those of the powerful radio jets. More information at http://www.eso.org/gen-fac/meetings/agnii2007/

"X-ray surveys: Evolution of accretion, star-formation and the large scale structure", Rodos island, Greece 2 - 6 July, 2007

Chandra and XMM-Newton extragalactic surveys have provided a wealth of exciting discoveries in the past few years. The largest fraction of the X-ray backgound has been resolved yielding the strongest constraints yet on the accretion history of the Universe. XMM-Newton systematically detects clusters of galaxies at high redshift providing invaluable cosmological information. Parallel to the observational constraints, theoretical modelling of cluster formation and evolution has also seen tremendous progress in the past few years. At the same time a large number of X-ray selected normal galaxies have been detected in both deep fields and wide field bright surveys, helping us to probe for the first time the star-formation rate and its evolution in X-ray wavelengths. Large area contiguous surveys start to probe the AGN clustering properties and their environment. The scope of the meeting is to examine in detail such recent X-ray survey findings and their cosmolog\ ical implications, paving the way for future X-ray missions.

Additional information can be obtained at email: xray07@astro.noa.gr or www : www.astro.noa.gr/~xray07

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HEADNEWS, the electronic newsletter of the High Energy Astrophysics Division of the American Astronomical Society, is issued twice yearly by the HEAD Secretary-Treasurer. The HEAD Executive Committee Members are:

    Comments, questions, or feedback to headsec@aas.org, Updated May 31, 2005