ELECTRONIC NEWSLETTER OF THE
HIGH ENERGY ASTROPHYSICS DIVISION OF THE AAS
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Newsletter No. 73 November 1998 |
- AAS Meeting in Austin, Texas
- 1999 HEAD Meeting: Announcement
- News from NASA Headquarters
- NASA/GSFC XMM Guest Observer Facility
- Rosat News and Demise
- Workshop on X-ray Interferometry, January 28-29, 1999
- Workshop on Small Missions for Energetic
Astrophysics: Ultraviolet through Gamma-Ray, February 22-26, 1999
- ASCA Symposium on Heating and Acceleration in the
Universe, 17-19 March 1999
- NATO Advanced Study Institute: The Neutron Star -
Black Hole Connection, June 7-18, 1999
- Meeting: X-ray Astronomy 1999 - Stellar Endpoints,
AGN and the X-ray Background, 6-10 September 1999
- 5th Compton Symposium, September 15-17, 1999
- HEAD in the News (Lynn Cominsky, HEAD Press Officer)
1. Notes from the Editor
(Alan Marscher, HEAD Secretary-Treasurer, marscher@bu.edu; phone: 617-353-5029)
have an e-mail exploder for announcements of general interest to HEAD members. If you
have an item that you would like to announce in this way or in the semiannual newsletter,
please send the announcement to me via e-mail and I will publish it in the next newsletter
or, if more urgent, send it out via e-mail to the HEAD e-mail list. (Back to Top)
1. 5-9 January 1999 AAS Meeting in Austin, Texas:
Main events of interest to HEAD members
Please note the following schedule of HEAD-related activities at the January 1999 AAS
meeting in Austin:
TBA: HEAD Executive Committee meeting
HEAD-Related Activities on Thurs. January 7
8:30 - 9:20 Rossi Prize presentation and lectures by Livio Scarsi and Jan van Paradijs
10:00 - 11:00: HEAD Special Session I: Gravitational Radiation from Astrophysical Sources
1:00 - 1:55 HEAD business meeting (open to public)
2:00 - 3:30 HEAD Special Session II: Exotic Neutron Stars
HEAD-Related Activities on Fri. January 8
8:30 - 9:20 Invited talk by Vicki Kaspi on The Neutron Star/Supernova Connection
10:00 - 11:30: Special session on X-Ray Astronomy with Astro-E
HEAD-Related Activities on Sat. January 9
10:00 - 11:30: Special session on New Science Prospects with 100-Day Ballooning
11:40 - 12:30 Heineman Prize Lecture by Roger Blandford on New Horizons in Black Hole
Astrophysics
(Back to Top)
2. 1999 HEAD Meeting: (Gordon Garmire, HEAD Chair,
and Eureka Scientific, host of meeting)
The next meeting of the High Energy Astrophysics Division (HEAD) of the American
Astronomical Society will take place on
April 12 - 15, 1999 (Monday - Thursday) at the Francis Marion Hotel in Charleston, South
Carolina. The chair of the local organizing committee is James Neff, College of
Charleston, Charleston, SC. Meeting details and links can be found at the meeting website:
http://www.eurekasci.com
ABSTRACTS ARE DUE to the AAS by February 10, 1999.
NEW ABSTRACT PROCEDURE !!
The HEAD executive committee has decided that the Meeting abstracts should be published
in an archival publication that can be referenced. Therefore, all submitted abstracts will
be published in the Bulletin of the American Astronomical Society (BAAS), which will be
available at the meeting. In order to meet this tight publication deadline, all abstracts
will be submitted to and processed by the AAS in LaTex format by the due date of February
10, 1999. Abstracts submitted after this date will only be accepted at the discretion of
the Scientific Organizing Committee and will be published in the BAAS in a later issue.
You may submit your abstract via the WWW (highly recomended) or by email. WWW submission,
LaTex abstract forms and instructions can be found online at: http://www.aas.org/~abstract/abstracts.html
A copy of the LaTex form is available at the meeting web site (see above). You may submit
multiple abstracts as first author, BUT, all abstract submissions beyond the first cost
$30 each. You will be charged at registration. We look forward to your participation at
another successful meeting. (Back to Top)
3. News from NASA Headquarters (Alan Bunner,
Paul Hertz, and Lou Kaluzienski)
The high energy astrophysics program at NASA is a robust combination of currently
operating missions, missions in development, future missions, data analysis, and
supporting research and technology. There is a little bit of news about each of them.
- The shipping of AXAF from TRW to Kennedy Space Center has been delayed by software bugs
and testing procedures taking longer than scheduled. This will cause a two to four month
delay in the AXAF launch. NASA has directed a review of AXAF, by NASA Chief Engineer Dr.
Daniel Mulville, to be completed by mid-January 1999. A new shipment date and a new launch
date will be confirmed after the review.
- The selections have been made in the UNEX program. The Cosmic Hot Interstellar Plasma
Spectrometer (CHIPS) spacecraft will use an extreme ultraviolet spectrograph during its
one-year mission to study the Local Bubble; the Principal Investigator for CHIPS is Mark
Hurwitz of the University of California, Berkeley. The Inner Magnetosphere Explorer (IMEX)
will study the response of Earth's Van Allen radiation belts to variations in the solar
wind; the Principal Investigator for IMEX is John Wygant of the University of Minnesota.
- The evaluation of MIDEX proposals is continuing; selection of approximately 4 missions
for Phase A studies is anticipated in mid- January 1999. NASA received 31 MIDEX proposals
and 4 Mission of Opportunity proposals in response to the MIDEX AO.
- There are several current and upcoming opportunities to propose for technology
development funding. Proposals for Explorer program technology development (including
instrument technology) are due January 22, 1999 (see http://www.hq.nasa.gov/office/oss/nra/98-oss-10/).
NASA will be releasing an NRA for cross-cutting technology development very soon (draft
release expected in November 1998, NRA release expected in January 1999). The NASA
Institute for Advanced Concepts also solicits proposals every six months (http://www.niac.usra.edu/). For more information,
contact Glenn Mucklow (gmucklow@hq.nasa.gov).
- An AO for flight instruments and interdisciplinary scientists for the GLAST mission is
in preparation. NASA expects to release a draft GLAST AO to the community for comment in
January 1999.
- Every two years, NASA reviews its operating astrophysics missions (i.e. those within the
Structure and Evolution of the Universe theme and those within the Astronomical Search for
Origins theme) to aid in allocating scarce mission operations and data analysis
(MO&DA) funds. The results of the 1998 Senior Review has been released. As a result of
this evaluation, RXTE and CGRO have been extended through FY02, ASCA has been extended
through FY01, and ROSAT has been extended through FY00. The text of the 1998 Senior Review
report may be found at http://www.hq.nasa.gov/office/oss/codesr/senior98.html.
- Guest investigator peer reviews and selections have been completed for AXAF Cycle 1,
CGRO Cycle 8, and RXTE Cycle 4. The ASCA Cycle 7 peer review will be held in November
1998. ROSAT Cycle 9 has been canceled due to the HRI failure. As always, the results of
guest investigator peer reviews may be found on the various mission home pages. Links to
results for all NASA Space Science competitions may be found at
http://www.hq.nasa.gov/office/oss/codesr/. Currently open NRAs and AOs may be found at http://www.hq.nasa.gov/office/oss/research/open.htm.
- Next year will offer a full calendar of proposing opportunities at NASA for members of
the high energy astrophysics community. Here is a planning calendar. Note that all dates
are approximate and many are guaranteed to change. ROSS is the Research Opportunities in
Space Science omnibus NRA, expected to be released in late January 1999.
Opportunity Release Due Date
Explorer Technology Oct 23 Jan 22
XMM 1 Nov 16 Mar 31
HEA SR&T ROSS late April
ADP/LTSA ROSS early May
CGRO 9 early Feb early May
AXAF 2 early May early Aug
RXTE 5 mid April mid July
ATP ROSS mid July
ASCA 8 early June early Sep
Astro-E 1 early June early Sep
GLAST AO April September
SMEX September December
You can sign up for e-mail notification of all NASA space science research
opportunities at http://www.hq.nasa.gov/office/oss/announce/listserv.htm#research.
- NASA is preparing to begin its next round of roadmap activities and strategic planning.
These activities will support the National Academy of Sciences Survey of Astronomy and
Astrophysics (the Decadal report) and the next NASA and Office of Space Science strategic
plans. Two working groups have been established to advise NASA on high energy astrophysics
missions. The Gamma Ray Program Working Group is chaired by Neil Gehrels of Goddard Space
Flight Center. The X-ray Program Working Group is chaired by Steve Murray of the Center
for Astrophysics. Both groups will hold a series of meetings, including public sessions,
leading to recommendations to NASA next spring.
- Alan Bunner's advisory committee, the Structure and Evolution of the Universe
Subcommittee (SEUS) has a new chair. The outgoing chair, Roger Blandford of Caltech, is
leaving to chair the high energy astrophysics panel for the Decadal Survey. Bruce Margon
of the University of Washington has agreed to be the new SEUS chair. (Back to Top)
4. NASA/GSFC XMM Guest Observer Facility (GOF)
(Steve Snowden)
The X-ray Multi-Mirror (XMM) Observatory is the second cornerstone mission in the
European Space Agency's Horizon 2000 program, and is scheduled for launch 21 January 2000.
XMM will be an observatory-class X-ray facility for the first decade of the next century.
The XMM payload consists of three large-area 7.5m focal length X-ray telescopes and a 30cm
diameter optical/UV telescope (Optical/UV Monitor, OM), all of which will be in
simultaneous operation. The X-ray telescopes have CCD focal-plane detectors (European
Photon Imaging Cameras, EPIC), which provide ~6" (FWHM) imaging and moderate spectral
resolution over the 0.1-15 keV energy range. Two of the telescopes are also equipped with
reflection grating assemblies, which will provide high-resolution spectra through the
Reflection Grating Spectrometer (RGS). The OM has both broad-band imaging and grism
spectroscopy capabilities. Combined together, the effective area, energy resolution, and
angular resolution of the X-ray telescopes far exceeds previous observatories, and will
compliment the capabilities of AXAF. When combined with the simultaneous optical/UV
observations of the OM, XMM will prove to be an exceptionally powerful instrument for
investigating the universe. XMM will have a Guest Observer (GO) program which will be open
to participation by US astronomers. In addition, funding for successful US GOs will be
available through NASA. To support US participation in the XMM GO program, NASA has
organized an XMM Guest Observer Facility at the Goddard Space Flight Center. AO-1 will be
released 16 November 1998 with a due date of 31 March 1999.
Informational WWW pages with links to ESA program pages can be found at: http://heasarc.gsfc.nasa.gov/docs/xmm/xmmgof.html
The GOF can be reached by e-mail at: xmmgof@athena.gsfc.nasa.gov
For XMM questions there is an XMM help line at: xmmhelp@athena.gsfc.nasa.gov
The above information was also sent out as an e-mail distribution from the XMM GOF. If
you did not receive it in that manner, and would like to be included in the e-mail
distribution list to be used for future mailings, please e-mail xmmgof@athena.gsfc.nasa.gov with the subject
"mailing list". (Back to Top)
5. Rosat News and Demise
THE FIRST ROSAT HIGH RESOLUTION IMAGER SOURCE CATALOG (Dan Harris)
The ROSAT Consortium (the Max-Planck-Institut fuer extraterrestrische Physik, the
Goddard Space Flight Center, the Smithsonian Astrophysical Observatory, Leicester
University, and the Astrophysikalisches Institut Potsdam) announces the public release of
"THE FIRST ROSAT SOURCE CATALOG OF POINTED OBSERVATIONS WITH THE HIGH RESOLUTION
IMAGER" (ROSHRICAT). This catalog contains arcsecond positions and count rates of
detected sources from more than 2,000 public ROSAT HRI observations, including more than
5700 bright sources (signal-to-noise ratio > 4). The catalog consists of all primary
source parameters from the automated detection algorithm employed by the Standard Analysis
Software System (SASS). In addition each observation has been quality checked, both by
automatic algorithms and by detailed visual inspection. The results of this quality
checking are contained as a set of logical-value flags for each principal source
parameter. If a source parameter is suspect, the associated flag is set to
"TRUE"; parameters with no obvious problems maintain the default,
"FALSE", value. In addition to the catalog, data products for each screened
observation are also available. These data products include the screened source lists,
FITS images, and ASCII files containing information about obvious real sources not
detected by the SASS detection algorithms.
Detailed information about the catalog and methods of access to the catalog and data
products can be obtained from the ROSAT Results Archive web pages in the US, in Germany
and in the UK:
http://heasarc.gsfc.nasa.gov/docs/rosat/rra/RRA.html
http://hea-www.harvard.edu/rosat/rsdc_www/rra.html
http://wave.xray.mpe.mpg.de/rosat/rra
http://www.aip.de:8080/~rra
http://ledas-www.star.le.ac.uk/rra
Access to the command-line driven BROWSE interface to the ROSHRI catalog is also
available via telnet to either legacy.gsfc.nasa.gov, xray.mpe-garching.mpg.de or
ledas.star.le.ac.uk - in each case the username is xray, then type "browse
roshri" (no quotes) at the command line prompt.
The ROSAT High Resolution Imager Source Catalog will continue to be updated as new HRI
observations are screened and become public. New versions will be announced via the
electronic ROSAT Status reports and on the RRA web sites at MPE, GSFC, SAO, AIP and
Leicester. \BR
END OF THE ROSAT GUEST OBSERVER PROGRAMME (Mike Arida)
After eight years of successful operations it was agreed among the ROSAT institutions
in Germany, the USA, and the UK to officially terminate the guest observer programme of
the observatory. The reason for this decision is the irreversible damage of the High
Resolution Imager (HRI) due to an accident on 20 September 1998. The HRI was the only
focal plane instrument available for X-ray observations since September 1994, when the gas
supply of the Position Sensitive Proportional Counters (PSPC) effectively became
exhausted. ROSAT had an extraordinary long life compared with astronomy satellites in a
near earth orbit, longer than any other X-ray astronomy satellite.
The recent problems started on 28 April 1998 when the star tracker attached to the
X-ray telescope used for navigating the satellite failed. The remedy was to bring the star
tracker of the Wide Field Camera (WFC) into the loop of the attitude control system
(AMCS). This activity was initiated immediately and the DASA engineers were supported by
experts from the ground station (GSOC/DLR), MPE and Leicester University/RAL. The task
soon turned out to be more difficult than anticipated; one of the problems was the fine
tuning between the software of the AMCS and that of the star tracker, the latter never
designed to be incorporated into an active attitude control system. As a result the
satellite suffered from many safe mode triggers over the summer, and only a few scientific
observations could be performed during this period. At the end of August the situation had
improved significantly by fine tuning the parameters of the AMCS software, and almost
normal scientific operations were resumed. Shortly before a revised version of the AMCS
software was uplinked an 'accident' happened on 20th September: during a slew the pointing
direction of the satellite came close to the sun; as a result the HRI was irreversibly
damaged.
ROSAT was initiated by MPE in 1975 and became a collaborative project between Germany,
the United States and the United Kingdom in 1983. Germany built and operated the
spacecraft, and also provided the X-ray telescope including two X-ray cameras, i.e. the
Position Sensitive Proportional Counters. The United States provided the launch with a
Delta rocket and the High Resolution Imager as the third X-ray camera aboard, while the
United Kingdom contributed the Wide Field Camera operating in the extreme ultraviolet
range. The data analysis, archiving, and distribution has been done as a joint effort of
the ROSAT data centers: in Germany these are the Max-Planck-Institut fuer
extraterrestrische Physik (MPE) and the Institut fuer Astronomie und Astrophysik at the
University Tuebingen (IAAT), in the US the Goddard Space Flight Center (GSFC) and the
Smithonian Astrophysical Observatory (SAO), and in the UK the University of Leicester (UL)
and the Rutherford Appleton Laboratory (RAL).
After the launch on 1 June 1990 ROSAT carried out the first All Sky Survey with imaging
X-ray and EUV telescopes. This half year operation led to the discovery of some 80 000
X-ray and 500 EUV sources. In the following 7 1/2 years about 9 000 fields in the sky were
observed in a guest observer programme involving 650 principal investigators from 26
countries. Numerous discoveries have been made and more than 3 000 scientific publications
with more than 4 000 scientists as co-authors have been published until now. The ROSAT
discoveries concern almost all fields of astrophysics from the closest objects - moon and
comets - to the most distant ones - high redshift quasars -, from the smallest - single
neutron stars - to the largest objects in the universe - clusters of galaxies.
ROSAT will continue to have a strong impact on astrophysics. At present, the
utilization of the ROSAT archives is very high, and currently more than one ROSAT based
publication appears every day in the scientific literature. (Back to Top)
NASA is sponsoring a two day workshop on the science and technology of X-ray
Interferometry. This has the potential of achieving micro-arc second imaging, which could
ultimately lead to a micro arc second imaging mission, MAXIM. Please see the website at
http://maxim.gsfc.nasa.gov (see above). We invite interested scientists and engineers to
help define what could become one of the most exciting astrophysical initiatives of the
next decade. The workshop will be on January 28 and 29, 1999. and is hosted by Webster
Cash and the Center for Astrophysics and Space Astronomy at the University of Colorado in
Boulder. NASA and CASA will be covering the basic expenses for the meeting and no
registration fee will be charged. The primary goal of the workshop is to establish the
scientific goals of micro arc second imaging and the technical challenges of X-ray
interferometry. The MAXIM study group has already identified direct imaging of black hole
event horizons as a central scientific theme for the meeting. The workshop will further
clarify the scientific return and technical challenges of such a mission. The workshop
will also consider other micro arc second imaging astrophysics, such as detailed pictures
of stellar coronae, and high energy phenomena in planetary systems. An outcome of the
MAXIM study is practical concepts for achieving x-ray interferometry. The MAXIM group has
already identified some very promising technologies. Presentations on the current state of
the art will be made. Additional ideas and concepts to achieve the technical requirements
are welcome. Papers on either science with micro-second angular resolution, or the
technology to achieve this are welcome. These will by default be poster presentations.
Some of these papers may be selected for oral presentation. To register for the meeting
and submit a paper visit http://maxim.gsfc.nasa.gov/max_workshop.html
For information on travel to the workshop visit http://casa.colorado.edu/~wcash/Travel/travel.htm
Webster Cash can be contacted at 303-492-4056 or send e-mail to cash@casa.colorado.edu for additional
information.
(Back to Top)
7. Workshop on Small Missions for Energetic
Astrophysics: Ultraviolet through Gamma-Ray, February 22-26, 1999 (Steven Brumby)
J. Robert Oppenheimer Study Center, Los Alamos National Laboratory
Abstracts due DECEMBER 20, 1998
Register by JANUARY 26, 1999
Web site: http://www.nis2.lanl.gov/smsat_conf/workshop.html (Sorry, there seems to be some
protection against a direct link to this site from here.)
For the next decade, the major milestones for energetic space astrophysics have become
clear: FUSE in the ultraviolet, CONSTELLATION in the x-ray, and GLAST in the gamma-ray
band. These missions aim squarely at the most important questions of our day. However,
small missions (MIDEX, SMEX, UNEX, and others) are also critical. They answer questions
unanswered by large missions, particularly because they allow the rapid application of new
technologies. "Small Missions for Energetic Astrophysics" will bring the
community together in a forum to discuss small missions that can be launched in the second
half of the next decade. The agenda will combine astrophysical problems and creative small
mission solutions.
Scientific Session Topics: Active galactic nuclei, Compact objects/binaries
Extragalactic diffuse background and the intergalactic medium, Gamma ray bursts,
Interstellar medium, Supernovae and supernova remnants, Stellar astrophysics, White dwarfs
and isolated neutron starsl, Emerging technologies for small satellite missions
The meeting will begin Monday morning, February 22 and end at noon on Friday, February
26. Wednesday afternoon will be free for skiing, etc., and the conference dinner will take
place on Thursday. Each morning and afternoon session will have two 30 minute invited
talks and six 20 minute contributed talks. Posters will be displayed outside the meeting
room. The invited talks will define the scientific topics of the sessions. The contributed
talks and posters will mainly deal with missions, enabling technologies, and science
topics. The morning sessions go from 8:30 to noon with 30-minute coffee/poster breaks. The
afternoon sessions run from 1:15 to 5 PM with 45-minute coffee/poster breaks.
(Back to Top)
8. ASCA Symposium on Heating and Acceleration in
the Universe,
17-19 March 1999, Hachiouji, Tokyo, Japan
Web site: http://www.astro.isas.ac.jp/xray/ascasymp4/
This is the 4th ASCA symposium following three fruitful meetings held in 1994 (Tokyo
Metropolitan Univ.), 1996 (Waseda Univ.), and in 1997 (Washington D.C.), celebrating the
6th anniversary of ASCA's launch. The purpose of the symposium is to bring together the
recent observational results obtained during the six successful years of ASCA and the
achievements of other space missions with possible inclusion of the long awaited AXAF, and
to deepen our understanding of the X-ray and gamma-ray universe and its evolution.
Through high resolution spectroscopic and imaging studies of cosmic objects, we are
entering into an exciting new stage of high-energy astronomy. The field has been enriched
in earlier periods through discoveries of X-ray emission from all categories of objects.
Now, the high quality of the observational data allows us to look almost directly at the
underlying physical processes in the X-ray emitting objects. Heating of plasma and
acceleration of particles are the key processes working in the strong X-ray and gamma-ray
emitting systems. The purpose of this symposium is to reach deeper understanding of
physical mechanisms which cause strong heating or acceleration to high energy in the
universe in the light of new observational data. We hope the symposium provides an
occasion for substantial discussion about the most energetic physical processes in
celestial objects. The symposium will address the following scientific topics.
1. Heating in galaxies and clusters of galaxies
2. Acceleration in SNRs and pulsars
3. Acceleration in jets --- from galactic micro QSOs to Blazars
4. Heating in accretion disks
5. New frontiers in future missions --- Astro-E, AXAF, XMM, Abrixas, etc.
The symposium has been planned to commemorate the achievements and contributions of
Professor Fumiyoshi Makino at ISAS and Professor Masaru Matsuoka at RIKEN who are both
going to retire in March from their present chairs.
(Back to Top)
9. NATO Advanced Study Institute: The Neutron Star
- Black Hole Connection
June 7-18, 1999, Elounda, Crete, Greece (Appl. Deadline: February 15, 1999)
Web site: http://www.mitos.com.gr/conf/n_starASI99
e-mail: mitos@step.gr
This NATO ASI is the fifth of a series focused on neutron stars. The current school
will cover several topics among which are the following: Pulsars, accreting neutron stars,
black holes, supernovae, gamma-ray bursts, magnetars, accretion discs.
LECTURERS (preliminary): A. Alpar, D. Bhattacharya^, L. Bildsten, G. Fishman, C.
Kouveliotou, N. Kylafis, W. Lewin^, D. Lorimer, P. Meszaros, S. Perlmutter^, L. Piro, S.
Rappaport, S. Shapiro^, G. Srinivasan, R. Sunyaev^, C. Thompson, J. Truemper, E. van den
Heuvel, M. van der Klis, J. van Paradijs, J. Ventura, M. Weisskopf
^ not yet confirmed
NATO restricts the number of participants in an ASI to less than 100. In the past these
schools have been very popular, and several applicants were turned down to meet NATO
requirements. We strongly advise, therefore, early expression of interest in participating
in the school.
(Back to Top)
10. Meeting: X-ray Astronomy 1999 - Stellar
Endpoints, AGN and the
X-ray Background, 6-10 September 1999, Bogogna, Italy (Nick White)
Web site: http://xray.gsfc.nasa.gov/bologna
X-ray Binaries and the X-ray background were the first two classes of cosmic X-ray
source discovered. The X-ray binaries provide a natural laboratory for probing the extreme
environments of black holes and neutron stars. A substantial fraction of the X-ray
background is the superposition of AGN, which are powered by supermassive black holes. The
Symposium will present observations from ASCA, AXAF, BeppoSAX, CGRO, ROSAT and RXTE and
will discuss their implications for the origin of the X-ray background and models for
accretion on all scales. The meeting is organized by the NASA Goddard Space Flight Center,
the University of Bologna and the CNR in Bologna. It will be held at the CNR Conference
Centre. Further details will be posted on the conference web site. (Back to Top)
11. 5th Compton Symposium, Portsmouth, New
Hampshire, September 15-17, 1999
HOSTED by the University of New Hampshire and the CGRO Science Support Center (Mark
McConnell)
Information and forms can be found at the web site: http://wwwgro.unh.edu/compton5/
The scientific program and format for the 5th Compton Symposium will generally follow
the format for the previous Compton symposia. A mixture of invited talks, contributed
papers, and poster presentations will cover the current status of observational and
theoretical gamma ray astrophysics. Observational results from CGRO, and results from XTE,
SAX, AXAF, ASCA, ROSAT, ground-based VHE gamma-ray and radio observatories, and other
ground-based and space missions related to astrophysical sources with emission greater
than 10 keV are solicited. A session devoted to the GLAST mission is also planned. Gamma
ray bursts and solar flares will only be summarized in invited reviews. (Back to Top)
2. HEAD in the News (Lynn Cominsky, HEAD Press Officer)
Although we have not had any official HEAD press conferences since the last newsletter,
there has been plenty of newsworthy activity! The following is a short synopsis of HEAD
press releases that were distributed through the AAS e-mail exploder to over 1000
journalists and public information officers, worldwide. Many received extensive coverage
in the daily and televised newsmedia.
Millisecond pulsars: In January, Frank Marshall, Eric Gotthelf and W. Zhang (GSFC) and
John Middleditch (LANL) reported the discovery of an ``original'' spin pulsar with a
period of 16.1 ms. The discovery was made in data from the Rossi X-ray Timing Explorer,
and confirmed with observations using ASCA. ASCA observations also confirmed the pulsar's
association with the plerionic supernova remnant N157B, in the Large Magellanic Cloud.
Spinning roughly twice as fast as the Crab pulsar, N157B holds the record for the fastest
X-ray pulsar that has not been spun up by accretion from a companion star. Its magnetic
field appears to be a few times weaker than that of the Crab, and it is approximately
4000-5000 years old. For further information about N157B, see Marshall et al. 1998, ApJ,
499, L179.
The record for the fastest X-ray emitting recycled pulsar was broken in July, when
Michiel van der Klis and Rudy Wijnands of the University of Amsterdam discovered 2.5 ms
pulsations from SAX J1808.4-3658. Originally seen as a transient bursting X-ray source in
observations using BeppoSAX (in't Zand et al. 1998), it is the first case of a source
which emits both Type I (thermonuclear) X-ray bursts as well as X-ray pulsations. (The
``bursting pulsar'' GRO 1744-28 emits bursts which are not Type I.) Further analysis of
the RXTE data by Deepto Chakrabarty and Ed Morgan (MIT) revealed a 2 hour orbital period,
with the very small orbital size of about one light second. The mass of the companion star
inferred from these measurements is only about 0.1 solar masses, and the magnetic field is
about 10^8 Gauss. SAXJ1808.4-3658 provides the best case thus far for the long sought
``missing link'' that is the evolutionary connection between the low mass X-ray binaries
and the recycled millisecond radio pulsars. For further information, see Wijnands and van
der Klis 1998, Nature, 394, 344; Chakrabarty and Morgan 1998, Nature, 394, 346 and in't
Zand et al. 1998, A&A, 331, L25.
The Strange Case of CI Cam: In April, a very intense but short X-ray outburst from the
star CI Cam had astronomers rushing to determine whether the compact object in this system
was a neutron star or a black hole. Since the entire X-ray outburst from this system
peaked in a mere 12 hours, and lasted only two days, we may not find out until it flares
up again. What we do know, however, is that it emitted two radio jets which each expanded
in a corkscrew pattern, as though emitted from a precessing accretion disk. The radio jets
were observed using the VLA and the VLBA, by Robert Hjellming (NRAO) and Amy Mioduszewski
(JIVE). The radio and X-ray outbursts coincided with a dramatic rise in the intensity of
the optical star CI Cam, which was observed by Mark Wagner (OSU) and Sumner Starrfield
(ASU), using the Perkins 72-inch telescope at the Lowell Observatory. The X-ray source,
XTE J0421+560, studied by Walter Lewin (MIT) and his international team of collaborators,
may be the first new black hole transient seen by RXTE since its launch at the end of
1995. During its short lifetime, it was also detected by CGRO, ASCA and BeppoSAX. Possibly
similar to the microquasars, or perhaps SS433, CI Cam/XTE J0421+560 is a system that well
deserves the multiwavelength campaign which was mounted on its behalf. For further
information, see Frontera et al. 1998, A&A, 339, L69, and IAU circulars starting with
#6857.
Gamma-ray Bursts: A gamma-ray burst which occurred on December 14, 1997, and which was
detected by CGRO, BeppoSAX and RXTE at high energies, has been identified with a faint
galaxy located 12 billion light years from Earth. The burst lightcurve was studied by
BATSE, while the position of the source was determined using BeppoSAX. Ground based
observers, including Jules Halpern and David Helfand (Columbia U) and John Thorstenson
(Dartmouth U) used this position to find the visible afterglow using the 2.4 meter
telescope at Kitt Peak. Follow up observations using the 10-m Keck II telescope by George
Djorgovski and Shri K Kulkarni (Caltech) determined the redshift z=3.42. For a 50 s
duration burst, the electromagnetic energy radiated from the object is approximately that
emitted by our entire Galaxy over a period of a few centuries. This led to the widely
publicized claim that scientists had detected the ``biggest explosion since the Big
Bang.'' For further information, see the May 7 issue (Vol. 393) of Nature (Kulkarni et
al., p. 35; Halpern et al., p. 41 and Ramaprakesh et al., p. 43.)
Magnetars and Soft Gamma Repeaters: Six years ago theorists Robert Duncan (UT Austin)
and Christopher Thompson (UNC) predicted the existence of neutron stars with magnetic
fields hundreds of times stronger than previously observed. They also calculated that
these extremely strong magnetic fields are responsible for heating the neutron star
surface and for producing starquakes, which result in the repeated bursts which are seen
at soft gamma-ray energies. Over the past twenty years since SGRs were first noticed, they
have been found to be associated with supernova remnants, strengthening the likelihood
that neutron stars are involved in the production of the repeated bursts. Now, new
observations of SGR 1806-20 by Chryssa Kouveliotou (MSFC), Stefan Dieters (UAH), Jan van
Paradijs (UAH/U of Amsterdam) and Tod Strohmayer (GSFC) have shown that SGR 1806-20 is a
7.5 s pulsar, with a spin down rate that implies its magnetic field is in the range 2 - 8
times 10^14 Gauss. The timing observations used data from RXTE and ASCA, and are
summarized in a paper which appeared in Nature. (Kouveliotou et al. 1998, Nature 393,
235.) Also see Thompson and Duncan, MNRAS, 275, 255 (1995) and ApJ, 473, 322 (1996).
In July, a new SGR (the fourth now known) was discovered and positioned near the
supernova remnant G337.0-0.1 by an international collaboration which included scientists
from BATSE (led by Chryssa Kouveliotou (MSFC)), and Ulysses/IPN (led by Kevin Hurley
(UCB)). The new source is named SGR 1627-41, and at least 26 bursts have been detected
thus far. For more information, see the IAU Circulars (beginning with #6944), or check out
the information on the web pages http://www.magnetars.com
or http://www.magnetars.com or
http://ssl.berkeley.edu/ipn3/sgr1627-41.
In August, a tremendous burst from SGR 1900+14 had an unexpected and dramatic effect on
the atmosphere of the Earth. Located at a distance of around 20,000 light years, near the
supernova remnant G 42.8+0.6, the flash was able to briefly ionize the upper atmosphere on
the night-side of the Earth to day-time conditions. Ionization measurements were made by
Umran Inan (Stanford U), while the spectacular burst was detected by at least seven
high-energy spacecraft, beginning with a report (IAU Circ. #7002) from the KONUS
experiment on the Global Geo-sciences Wind spacecraft by Tom Cline (GSFC), E. Mazets and
S. V. Golenetskii (Ioffe Physical-Technical Institute). In June, a team of scientists
using RXTE had observed about 50 bursts from this source (IAU Circ. #6929), while in
April, 5.2 second pulsations had been discovered by a team using ASCA (IAU Circ. #7001).
Comparisons of the pulses seen with the two satellites allowed the pulsar's spin down rate
to be determined, and a 5 x 10^14 Gauss magnetic field to be calculated. Also associated
with the super-burst was an unusual transient nebular radio source, which appeared to be
powered by the burst (Frail, Kulkarni and Bloom, submitted to Nature). For
furtherinformation,
see the web sites: http://www.magnetars.com or http://ssl.berkeley.edu/ipn3/sgr1900+14.
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