ELECTRONIC NEWSLETTER OF THE
HIGH ENERGY ASTROPHYSICS DIVISION OF THE AAS
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Newsletter No. 75 November 1999 |
- Obituary: Dr. Jan van Paradijs
- High Energy Astrophysics Division special sessions at the 195th AAS Meeting, Atlanta, GA, January 11-15, 2000
- News from NASA Headquarters
- HEAD in the News (6/99 - 10/99)
- NASA NRA: "Advanced Cross-Enterprise Technology Development for NASA Missions"
- Swift Satellite Selected for 2003 Launch
- XMM Prepared for Launch
- Astro-E in Final Testing
- NASA Chandra X-Ray Observatory
- HETE Readies for Early 2000 Launch
- BeppoSAX data at the HEASARC
- The 2nd ROSAT HRI Source Catalog
- Report on NATO Advanced Study Institute on "The Neutron Star - Black Hole Connection"
- 2000 HEAD Meeting, Honolulu, Hawaii, November 5-10, 2000
- ROSSI 2000: Astrophysics with the Rossi X-ray Timing Explorer, Greenbelt, Maryland, USA, March 22-24, 2000
- Invitation to Join in the APS Meeting in April/May 2000
- INTEGRAL Spring School: "Observing with INTEGRAL + Gamma-Ray, Nucleosynthesis," Les Diablerets, Switzerland, March 29 - April 1, 2000
- 30th SAAS FEE ADVANCED COURSE: "High-Energy Spectroscopic Astrophysics," Les Diablerets, Switzerland, April 3-8, 2000
- 4th INTEGRAL Workshop: Exploring the Gamma-ray Universe, Alicante, Spain, September 4-8, 2000
- Inst. for Theoretical Physics program for Fall 2000: ``Spin and Magnetism in Young Neutron Stars,'' U. California, Santa Barbara
- 33rd COSPAR Scientific Assembly, Warsaw, Poland, July 16-23, 2000
from the Editor (Alan Marscher, HEAD Secretary-Treasurer, marscher@bu.edu; phone: 617-353-5029)
If you receive a hard-copy of this newsletter, it means
that I do not have a working e-mail address for you.
In this case, if you do in fact have an e-mail address, please send me
e-mail so that I can update your address. Thanks.
The HEAD Web site has been moved to the Web site of the American Astronomical
Society (http://www.aas.org/head). It was last updated in early summer 1999,
although I plan to update it in December. At the web site, you will find past
issues of the Newsletter, information on meetings, links to other sites of
interest, and general information about HEAD.
We also 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.
This will be my last issue as editor of the HEAD Newsletter. Paul Hertz
has agreed to run for the position of secretary/treasurer and since
he is (as usual for this post) unopposed, I will stick my neck out and
welcome him as my successor, effective after the January AAS meeting.
It has been my pleasure to serve you and only wish that I had
time to update the web site and e-mail membership list more frequently!
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1. OBITUARY: Dr. Jan van Paradijs 1946-1999
Johannes (Jan) Antonius van Paradijs, a distinguished and prolific
high-energy astrophysicist, died on November 2, 1999, in Amsterdam, after a
long illness. Van Paradijs shared HEAD's 1998 Bruno Rossi prize with the
BeppoSAX team for his co-discovery of the first optical afterglow
associated with a gamma-ray burst that occurred on February 28, 1997. He
was also awarded the 1983 Pastor Schmeits Prize for his work on the theory
of X-ray bursts and the 1999 Physica Prize of the Dutch Physical Society
for his breakthrough gamma-ray burst work.
Van Paradijs was a Professor of astronomy at The University of Amsterdam,
as well as the Pei-Ling Chan eminent scholar in astrophysics at The
University of Alabama in Huntsville. Jan split his time between the
Netherlands and Huntsville, where he worked with UAH graduate students and
collaborated with the Compton Gamma Ray Observatory/BATSE team at the Space
Sciences Lab at NASA's Marshall Space Flight Center. Jan's recent work in
Huntsville was done in collaboration with his wife, astronomer Chryssa
Kouveliotou, whom he married in 1992. He also worked with many Dutch
graduate students in Amsterdam, including Paul Groot and Titus Galama, who
worked with him on the optical afterglow discovery. Other notable former
students who worked with van Paradijs include Ralph Wijers, Marten van
Kerkwijk, Erik Kuulkers and Steve Howell.
Van Paradijs earned his undergraduate and doctoral degrees from the
University of Amsterdam, and was a research scientist at the University of
Amsterdam from 1970-1988. From 1977-1979, Jan was a visiting scientist at
MIT's Center for Space Research, where he collaborated with Prof. Walter
Lewin and the SAS-3 group, making major contributions to the study of X-ray
bursts, and participating in the discovery of the first associated optical
bursts. Jan was named full Professor at the University of Amsterdam in
1988. In 1993, he was named to the endowed Pei-Ling Chan eminent scholar
post at UAH. In 1998, Jan was elected member of the Hollandse Maatschappij
der Wetenschappen in Haarlem (the oldest scientific society in Holland) and
in 1999 he was elected member of the Academia Europea (the European Academy
of Sciences in London).
Van Paradijs published more than 300 scientific papers, including the
recent "Perspective" article in the October 22 issue of the journal
"Science", written shortly before his death, on possible links between
gamma ray bursts and super novae. He was the co-editor or co-author of at
least eight books, including the conference proceedings volumes "The Lives
of the Neutron Stars", and "The Many Faces of Neutron Stars" as well as the
review book "X-ray Binaries" which is the best and most recent summary of
the field to which he made many contributions.
Many of his colleagues over the years were deeply affected by Jan's
untimely death. "Jan was one of the most knowledgeable, productive, and
wide-ranging workers in our field, a master of both observational and
theoretical high-energy astrophysics," said Dr. Jerry Fishman, the BATSE
principal investigator at NASA/Marshall. "He was near the top of everyone's
list of the world's great astrophysicists." According to HEAD Press Officer
Lynn Cominsky who worked with Jan at MIT while she was a graduate student,
"Jan was one of the first truly 'multiwavelength' astronomers. He was able
to synthesize optical and x-ray data to see the entire compact binary
picture--and it led him to important physical insights." MIT Professor
Walter Lewin, a close collaborator said "For over 20 years Jan had a very
large positive impact on my personal life and on my science." And his
colleague at the University of Amsterdam, Professor Ed van den Heuvel
recalled "Jan was a scientist of extraordinary caliber. It was not a
coincidence that Jan's group was the first to make an optical
identification of a BeppoSAX GRB: they were mentally prepared and trained
for it thanks to Jan's foresight. We all miss Jan very very much, as a
colleague and a friend."
Van Paradijs served on the boards of directors of the Netherlands
Foundation for Research in Astronomy and the European Astrophysics Doctoral
Network, and was a HEAD AAS and RAS member of long standing. Jan also
spent much time trying to spread his love of astronomy to the public: he
was a long-time director of the Dutch amateur-astronomer oriented Simon
Stevin Observatory, and he gave frequent public lectures in remote villages
all over Holland. He is survived by his wife Chryssa, his two children by
a previous marriage, and by three grandchildren.
A special memorial service will be held for Jan van Paradijs, in
Huntsville, AL on December 1, 1999. Travel funds for young astronomers are
being set up in Jan's memory at both the University of Alabama, Huntsville
and at the University of Amsterdam. Please contact Jerry Fishman
(jerry.fishman@msfc.nasa.gov) or
Ed van den Heuvel (edvdh@astro.uva.nl) for
additional information.
---Lynn Cominsky, HEAD Press Officer
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2. High Energy Astrophysics Division special sessions at the
195th American Astronomical Society Meeting, Atlanta, GA, January 11-15, 2000
HEAD I: Astrophysical Jets, Thursday, January 13, 10:00 - 11:30 am
Directed, high-velocity outflows or jets are becoming the norm among
astrophysical sources of high energy photons. From active galaxies
to gamma-ray bursts to microquasars to pulsars, jets seem to
be everywhere. This session will explore some of the recent
observational results and theoretical issues illuminating this always
fascinating topic.
- Observations of Jets in Galactic and Extragalactic Sources:
John Biretta - STSI
- Formation of Jets in AGN:
Mitchell Begelman - JILA, University of Colorado
- Simulations of Relativistic Jet Formation:
David L. Meier - JPL
HEAD II: The Highest Energy Gamma-Rays, Cosmic Rays and Neutrinos,
Thursday, January 13, 2:00 - 3:30 pm
Exploring the extremes of nature (or at least of our observational
windows) often presents new puzzles and sometimes new pieces to
old puzzles. Such is the case in the fields of high-energy gamma-ray
and cosmic-ray astrophysics. Detection of gamma-rays with energies up
to 50 TeV from active galaxies and supernova remnants is revealing
new information on nature's most powerful accelerators. Meanwhile, the
sources of ultra-high energy cosmic rays, detected at energies beyond the
theoretical cutoff due to interaction with the microwave background, are
completely unknown. The detection of high-energy neutrinos
from astrophysical sources, possible within the coming decade, would
open up a new window to study these and other sources.
- Very High Energy Gamma Ray Astronomy:
Rene Ong, University of Chicago
- The Highest Energy Cosmic Rays:
Todor Stanev, Bartol Research Institute
- High Energy Neutrinos:
Francis Halzen, University of Wisconsin
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3. News from NASA Headquarters (Louis Kaluzienski)
a. ASTRO-E and XMM Guest Observer Programs
Approximately 150 Stage 1 proposals for US Guest Observations during
the Phase 1 observing period of ASTRO-E were received and evaluated by
a US science peer panel during the first week of November. The
proposals requested a total of
~ 16.5 Msec of observing time, representing an oversubscription of ~
4.9:1 of the time available to US GO's during the initial viewing
phase. The set of recommended proposals will be merged with approved
Japanese GO proposals at a meeting planned for December 2-3, and the
final integrated target list posted at the ASTRO-E website
(
http://heasarc.gsfc.nasa.gov/docs/astroe/astroegof.html) around
December 10. US PI's with approved observations will be invited to
submit Stage 2 (cost) proposals, and it is anticipated that final
selections will be announced in March 2000. The mission is currently
planned for launch in early February.
ESA has completed its science peer review of proposals for guest
observations on the XMM mission, and it is anticipated that the results
of the review will be announced in early December. US PI's awarded
observing time on XMM will be notified by NASA in late December/early
January of the opportunity to submit Stage 2 cost proposals for support
of their investigations. It is expected that the awards of XMM GO
grants will be announced in the April/May 2000 timeframe.
b. GLAST AO
A total of 20 proposals were received in response to the Announcement
of Opportunity for GLAST Flight Investigations (AO 99-OSS-03). There
were two proposals for the primary instrument, 3 for the secondary
instrument and 15 for interdisciplinary scientist. The peer review of
these proposals is planned for December with announcement of the final
selection anticipated in February.
c. High Energy Astrophysics SR&T Program
The review and budget assessment of proposals for participation in the
High Energy Astrophysics Supporting Research and Technology Program
received in response to the ROSS-99 NRA has now been completed. A
total of 53 proposals were received, of which 34 proposals have been
recommended for funding. Based upon the final Office of Space Science
Research and Analysis program budget, the total funding awarded to
selected proposals during FY00 is ~ $7.9M. Due to the recent
restructuring of the OSS R&A Program, proposals for participation in
the HEA SR&T Program will be solicited on an annual basis, commencing
with the ROSS-2000 NRA. During the transition from the current
three-year cycle, projects selected under the ROSS-99 NRA will reflect
a mix of 1-, 2-, and 3-year grant awards.
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4. HEAD in the News (6/99 - 10/99) (Lynn Cominsky, HEAD Press Officer and
Christopher Wanjek, SEU Science Writer)
In the past four months, many exciting discoveries in High Energy
Astrophysics were publicized through the AAS e-mail distribution channel,
as well as an occasional Space Sciences Update by NASA. Many of these
stories received extensive coverage in the daily and televised news media,
including Time magazine, the New York Times and CNN. In addition, articles
were written about HEAD subjects by prominent scientists, including Michiel
van der Klis ("The Buzz of General Relativity" in Science 285, p. 1499) and
Jan van Paradijs ("From Gamma-Ray Bursts to Supernovae" in Science 286 p.
693).
A brief summary of non-Chandra related news is presented below. Chandra
news is relayed separately in the article by W. Tucker.
X-Ray Emission From The Event Horizon
ASCA observations of NGC 3516 by Paul Nandra, Rich Mushotzky (GSFC) and
others showed evidence for the final plunge of x-ray heated matter into the
AGN's central black hole. Buried in the X-ray emission spectrum typical
of AGN was a rare glimpse at a red-shifted absorption feature in the iron
K-alpha line. This very highly red-shifted feature was separate from the
overall redshift due to the movement of the AGN itself, and provides the
first direct evidence for accretion inflow onto a black hole. (See Nandra
et al., ApJ, 523, L17)
The Energy Output of the Universe
The total energy emitted by the growth of massive black holes can be 10-50
percent of that emitted by stars, according to Andrew Fabian (Cambridge).
The X-ray background
provides a good measure of this energy; most accretion power is absorbed
and re-emitted in the far infrared band. In Fabian's model, for every
ordinary quasar about ten more obscured ones are needed, meaning that the
growth of most massive black holes by accretion is hidden from view by the
traditional optical and ultraviolet and near infrared wavebands. Chandra
and XMM should detect obscured X-ray sources associated with massive black
hole growth. This result received attention at the X-ray Astronomy 1999
meeting in Bologna, Italy. (See Fabian,
http://mentor.lanl.gov/abs/astro-ph/9908064).
Gamma-Ray Burst Breakthroughs
It was another exciting year for gamma-ray burst science, as observers
around the world worked together to unravel the long-standing mystery of
GRBs. Among the newsworthy results:
Polarization and Strong Evidence for Jet Collimation Observed in GRB 990510
Observations with the new the VLT 8.2-m ANTU (UT1) telescope at Paranal,
Chile, showed evidence for polarization in the optical source, indicating
that synchrotron emission is involved in the afterglow, and measured a
redshift of z = 1.619 for the optical counterpart to GRB990510. The ESO
observations were triggered by an alert from CGRO/BATSE and were guided by
the counterpart location obtained with X-ray data from BeppoSAX and optical
images from the PLANET microlensing team at SAAO (see Wijers et al., ApJ
523, L33). Extensive multi-color optical and radio data were obtained for
this extremely well-covered burst, and showed clear evidence for jet
collimation reducing the apparent flux from the GRB by at least a factor of
100.
(see Harrison et al., ApJ 523, L121). See also the news article by Govert
Schilling inScience (284, p. 1251).
GRBs Used to Set Limits on the Mass of a Photon, and Frequency
Independence of the Speed of Light
Bradley Schaefer (Yale) has used the 220 microsecond rise time of GRB
930229 for photons of 30 keV and 200 keV to show that the speed of light is
independent of frequency to within a factor of 6 parts in 10^{-21}, 4
orders of magnitude better than previous limits. His result also sets a
mass limit for the photon of less than 2 x 10^{-11} eV. This result was
reported in the August issue of Physics Today, and can be read in PRL, 82,
p. 4964.
GRBs linked to Supernovae from Massive Stars
Observations of GRB 980326 carried out at the Keck Observatory's 10-m
telescope by Josh Bloom, Shri Kulkarni (Caltech) and others have found a
dramatic rebrightening of optical emission at the position of the gamma-ray
burst. The unique optical light curve has been interpreted as additional
light from a supernova accompanying the usual rapidly fading burst
afterglow. The supernova emission brightened slowly as the burst afterglow
decayed, and then disappeared completely after about nine months. The
initially blue afterglow spectrum appeared to turn red after about a month,
lending additional weight to the interpretation. (See Bloom et al., Nature,
401, 453, and also the news article by Schilling in Science, 286, p.395.)
GRBs Could Be Most Distant Observable Objects
At the Fifth Huntsville International Symposium on Gamma-ray Bursts, Daniel
Reichart and Don Lamb (Chicago) claimed that GRBs should be observable far
past the observational redshift limit of about 5, currently held by
quasars. New satellites such as HETE-2 and Swift should be able to detect
GRBs out to redshifts of 20, providing luminous probes of the early
universe. They also presented evidence that a supernova accompanied
GRB970228, confirming the Caltech group's earlier results for GRB 980326
(see Reichart et al., ApJ, 517, p. 692). For further news from the
Huntsville GRB Symposium, see the article by Schilling in Science (286, p.
893.)
News from the Compton Gamma-ray Symposium in Portsmouth, NH
Three press releases were issued from the Fifth Compton Gamma-ray
Observatory Symposium, held in Portsmouth, NH, September 15-17, 1999.
COMPTEL Gamma-ray Source Catalog Released
The first source catalog for objects emitting in the 1-30 MeV energy range
was released by the COMPTEL team at the Fifth Compton Gamma-ray Observatory
Symposium, held in Portsmouth, NH. The catalog is comprised of 63 sources,
31 of which are GRBs, with the rest being persistent emitters such as
neutron stars and black holes. The catalog will appear in the A&Ap
Supplement Series next year (Schönfelder et al., 2000).
New Method for Weighing Black Holes Combines X-ray and Radio Data
A new method has been devised for determining the mass of black holes which
are multi-wavelength emitters. Insu Yi (Korea Institute for Advanced Study)
and Stephen Boughn (Haverford College) used their new technique to weigh 10
massive black holes by measuring radio and x-ray flux ratios. They find
masses which agree with previous measurements of the same black holes using
more complicated methods. A side benefit of their method is the
determination of the mass accretion rate onto the black hole. (See Yi and
Boughn, ApJ, 515, p. 576).
First Evidence for Supernova Origin of Proton Cosmic Rays
Combining the discovery of a new radio supernova remnant with the gamma-ray
signature of pion decay in previously unidentified EGRET sources, Jorge
Combi (Instituto Argentino de Radioastronomia) and others have reported the
first evidence that directly links proton cosmic rays to their long-assumed
birthplace. The large, yet weak radio supernova remnant is located in our
Galaxy, at a distance of about 1600 light years, and occurred about 15,000
years ago. It was discovered in observations made with the Hartbeesthoek
radio telescope in Krugersdorp, South Africa.
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5. NASA NRA 99-OSS-05: "Advanced Cross-Enterprise Technology Development for NASA
Missions"
This is to draw your attention to the release by NASA of NRA 99-OSS-05,
"Advanced Cross-Enterprise Technology Development for NASA Missions",
soliciting proposals to develop critical space technologies that enable
innovative and less costly missions, and new mission opportunities through
revolutionary, high-risk, high-payoff technology advances. The NRA may be
found at the Office of Space Science homepage,
http://www.hq.nasa.gov/office/oss/ and clicking on "Research
Opportunities" and "Open Opportunities". Please note the compressed
schedule, with Notices of Intent due on 11/30/99 and proposals due by
12/23/99.
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6. Swift Satellite Selected for 2003 Launch (Christopher Wanjek and Lynn Cominsky)
NASA has selected the Swift multi-wavelength observatory for a MIDEX flight
opportunity, with launch scheduled in 2003. Named for the small, nimble
bird, as well as for its ability to swiftly turn and point its instruments,
Swift will operate for at least three years at a total cost of $163
million. Development is now underway at Goddard Space Flight Center,
Pennsylvania State University, in the UK and in Italy. The Swift team, led
by P.I. Neil Gehrels (GSFC), expects the satellite to detect over 300
bursts a year and determine their location relative to their host galaxies.
The multi-wavelength, rapid pointing capability of Swift will also open up
a new part of observational parameter space - Swift may detect different
types of high-energy bursts than those presently observed, as well as
observing flare-like phenomena that have not yet been studied.
Swift is a three-telescope space observatory for studying gamma ray bursts.
Although gamma-ray bursts are the largest known explosions in the universe,
outshining the rest of the universe when they explode unpredictably in
distant galaxies, the underlying cause of the explosion is a true mystery
of astrophysics. Swift will have the unique ability to rotate in orbit and
point its gamma-ray telescope, X-ray telescope, and ultraviolet/optical
telescope at gamma-ray bursts within minutes of the burst's first
appearance. Since gamma-ray bursts are believed to originate billions of
light years away, Swift will use these sources as beacons to probe distant
regions of the universe.
The main instrument aboard Swift is the Burst Alert Telescope (BAT). The
BAT will detect and locate about one gamma-ray burst per day, relaying a
1-4 arc minute position to the ground within about 15 seconds. This
position will then be used to "swiftly" re-point the satellite to bring the
burst area into the narrower fields of view of the two other Swift
instruments designed to study the afterglow: the X-ray Telescope (XRT) and
the UltraViolet/Optical Telescope (UVOT). These longer-wavelength
instruments will determine an arc-second position of a burst and determine
the redshift of the burst source. Meanwhile, the Gamma-ray Bursts
Coordinate Network (GCN) will inform other observatories of the active
burst.
Since GRBs are the most luminous objects in the Universe, they provide a
unique opportunity to probe distant host galaxies and provide information
about the early universe. Depending on evolution, GRBs might originate
from redshifts up to ~ 20. They may therefore be the most distant
observable sources of emission. It has been suggested that some GRBs may
be standard candles - if so, the extreme distances to GRBs would help
determine the cosmic distance scale.
When not catching gamma-ray bursts, Swift will conduct an all-sky survey in
hard x-rays that will be 100 times more sensitive than BeppoSAX and CGRO.
No complete hard X-ray survey has been performed since HEAO-A4 in the late
1970s.
A detailed description of Swift is available at http://swift.gsfc.nasa.gov.
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7. XMM Prepared for Launch (Christopher Wanjek, S. Kahn and F. Cordova)
XMM arrived by barge in French Guiana on September 27, after a ten-day
crossing from Europe. Numerous system checks on the satellite are now
underway before fuelling in mid-November. A thorough review of the
implications of the Chandra ACIS-I problem for XMM has been performed and
the appropriate measures have been taken. The launch aboard an
Ariane-5 rocket is scheduled for December 10. Steven Kahn (Columbia) is the
U.S. Principal Investigator for XMM's Reflection Grating Spectrometer
experiment and France Cordova (UCSB) is the U.S. Principal Investigator for
XMM's Optical/UV Monitor experiment. U.S. astronomers have access to guest
observing time, by means of an open competition with peer review. The
mission anticipates a 10 year lifetime.
For a daily mission update, refer to
http://www.arianespace.com/english/orbit_504log.html
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8. Astro-E in Final Testing (Christopher Wanjek and Richard Kelley)
Astro-E, Japan's fifth X-ray astronomy mission, readies for a proposed
February 2000 launch. Astro-E was subjected to the spacecraft bake-out
test and thermal-vacuum testing in October and has now entered into the
final integration testing. As of November 24, Astro-E will have
completed vibration testing. Astro-E covers the energy range 0.4 - 700
keV with the three instruments: an X-ray micro-calorimeter (X-ray
Spectrometer or XRS), X-ray CCDs (X-ray Imaging Spectrometer or XIS),
and the hard X-ray detector (HXD). The satellite was developed by the
Institute of Space and Astronautical Science (ISAS) in collaboration
with U.S. (NASA/GSFC, MIT) and other Japanese institutions. ISAS will
rename ASTRO-E shortly after launch. For a daily mission update with images,
refer to
http://www.astro.isas.ac.jp/xray/mission/astroe/astroe/gallery.html.
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9. NASA Chandra X-Ray Observatory (Martin C. Weisskopf and Harvey Tananbaum on behalf of the Chandra Team)
After its successful launch on July 23 the NASA Chandra X-Ray
Observatory is now routinely performing observations. Each of the early
calibration and activation observations provided new surprises and insights
- the discoveries of a point source at the center of Cas-A, a
spectacularly detailed jet and counter-jet in Centaurus A, a several
hundred kiloparsec long jet emanating from a putative point-like quasar,
new spatial structure in the Crab Nebula, fascinating spectral features
taken at high resolution from Capella, etc. We feel that it is fair to say
that the return from the CXO is beyond everyone's expectations.
A special session at the AAS meeting in Atlanta will be devoted to the
first results from Chandra. An associated poster session will include
more details from the initial on-orbit calibration phase of the mission
and additional early science findings. In the meanwhile, check out the
websites listed above for some of Chandra's first images.
OBSERVATORY PERFORMANCE
HRC:
The HRC-I is performing well and close to what was expected pre-launch
but there are some differences. First, the background rate is higher
than expected, but still only about 1-2 counts in a square arc second cell
for a 10**5 s integration. Next, the highest possible imaging quality has
not yet been achieved as high gain at the sweet spot has required the
development of new processing algorithms. Currently the image is comparable
to that achieved with ACIS (> 60% encircled energy in 1 arc second
diameter). Further improvements utilizing improved processing algorithms
are under study.
ACIS:
Following launch and initial calibration and activation (door openings)
the ACIS experiment was performing as it was prior to launch. In general,
the 2-8 keV background is quite low. For the front illuminated (FI) CCDs
the rate is about 6 x 10-7 counts per square arcsec per second and for the
prime back-illuminated device, S3, it is about twice this value. As with
the HRC, there are, of course, episodes of enhanced background - (factors
of several to over 10X) lasting from minutes to hours which may be
correlated with solar activity. The image quality observed on orbit is very
close to that predicted prior to launch. Unfortunately, the
front-illuminated (FI) CCDs have suffered some radiation damage and their
energy resolution has become position dependent over the face of each CCD.
Absolutely no damage has been observed in either of the two
back-illuminated (BI) devices.
During the on-orbit calibration period, but after the telescope
contamination covers were opened, the FI CCds of the ACIS instrument
began to exhibit increased charge transfer inefficiency (cti). We have
determined that the increased cti was associated with having ACIS at the
focus of the telescope during passages through the radiation belts.
Subsequently, ACIS is no longer placed in this position during belt
passages and the degradation in performance of the FI devices has ceased.
The BI CCDs remain unaffected. We are currently investigating, by means of
laboratory experiments, various possible processes that fit the details of
the situation. The most probable cause involves low energy protons
reflecting through the telescope. The importance of identifying the
mechanism is for guiding ground testing of CCDs and electronics to try to
mitigate and/or better cope with the damage and we are confident that some
improvements over the current status can be implemented.
The principal impact of the observed damage to the ACIS FI chips is that
now the energy resolution is a function of row number within the chips -
being as good as the pre-flight values near the readout but increasing by
as much as a factor of four depending on which chip and what energy at the
furthest from the readout. The imaging capability of these devices is
unimpaired. The degradation of the energy resolution also has no serious
impact on HETG spectroscopy. However, the row dependence of the energy
resolution has implications for one's observing strategy for imaging
spectrometry with no grating in place.
Observers with targets smaller than the field of view covered by a single
chip (8 arcmin in diameter) may well wish to consider obtaining their
image using the BI chip (S3) at the prime focus if imaging spectrometry is
a critical part of their objective. However, if imaging a field larger than
8 arcminutes is the prime goal, and insufficient photons for spectroscopy
are available then the I-array is still the likely array of choice. More
details as to choce of modes, etc. are available through the User Group.
HETG:
HETG performance has been as expected with no hints of performance
differing from ground calibrations. The HRMA-HETG-ACIS-S system is
achieving the expected resolving power -- over 700 for the MEG at 0.653
keV, and over 1100 for the HEG at 0.825 keV based on observations of
Capella. The "degraded" ACIS FI CCDs have energy resolution adequate for
use in order separation.
LETGS:
The LETGS comprising the LETG and the HRC-S has only begun to be utilized
and calibrated. Early calibrations have shown that the HRC-S background is
also higher than anticipated and higher than that experienced with the
HRC-I due to mis-timing between the anticoincidence and the detector
electronics. Nevertheless, with suitable windowing and post-facto pulse-
shape discrimination, the effect on a strong source as Capella is
negligible. Based on the first 80 ks observation of Capella, the impression
is that LETGS performs roughly as expected. The measured resolution, delta
lambda (FWHM) is 0.06 Angstrom, in agreement with ground calibrations.
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10. HETE-2 Readies for Early 2000 Launch (L. Cominsky and C. Wanjek)
The High-Energy Transient Explorer 2 (HETE-2), a multi-wavelength satellite
designed to detect and precisely localize gamma-ray bursts and to rapidly relay
these locations to other observatories, has entered into the final review stages
before its proposed January 23, 2000 launch. Within seconds, GRB positions from 10
arc-seconds to 10 arc-minutes for ~50 bursts per year will be transmitted from
HETE-2 to a global network of ground stations. These positions will then be
immediately relayed to the public over the Internet, thereby enabling sensitive
follow-up studies.
HETE-2 has three on-board instruments: FREGATE, WXM and SXC.
The French Gamma Telescope (FREGATE) is derived from the design of the successful
gamma-ray burst experiment Lilas aboard the Russian Phobos mission. Its prime
objectives are the detection and spectroscopy of gamma-ray bursts and the
monitoring of variable X-ray sources. The Wide-Field X-ray Monitor (WXM) consists
of two pairs of one dimensional position sensitive proportional counters, with a
coded aperture mask in front of each pair; one pair is used to determine the x-
and the other the y-position of the GRB. Finer positional localization is provided
by the Soft X-ray Cameras (SXC), which take advantage of the substantial photon
fluence in the low energy X-ray band, and the possibility of achieving finer
localization with a CCD/coded mask combination.
Various readiness reviews will be held through December and early January.
HETE-2 will be launched aboard a UELV Hybrid Pegasus from Kwajalein Missile
Range, so as to achieve an almost equatorial orbit. HETE-2, with a mission
lifetime for 6 months to two years, will also observe X-ray transients, X-ray
pulsars and soft-gamma repeaters (SGRs). The mission PI is George Ricker, MIT.
HETE-2 consortium institutions include MIT, RIKEN (Japan), Los Alamos National
Laboratory, CESR and CNES (France), CNR-TESRE (Italy), UC-Berkeley, University of
Chicago, UC-Santa Cruz, and Supaero (France).
For more information about HETE-2 see http://space.mit.edu/HETE.
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11. BeppoSAX data at the HEASARC (Lorella Angelini)
A large fraction of the public archival BeppoSAX data are now
available at the HEASARC. The data were provided by the BeppoSAX
data center in Rome to the BeppoSAX US coordinating facility
(http://heasarc.gsfc.nasa.gov/docs/sax/saxgof.html) established
at the HEASARC. The archive currently includes data from the
Narrow Field Instruments MECS, LECS and PDS. Also provided are
a copy of the latest software and calibration data and a mirror
of the BeppoSAX data center web site in Rome.
These data can be accessed via the HEASARC on-line services.
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12. The 2nd ROSAT High Resolution Imager Source Catalog (Michael Corcoran)
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 an update to "THE ROSAT SOURCE CATALOG
OF POINTED OBSERVATIONS WITH THE HIGH RESOLUTION IMAGER" (ROSHRICAT).
This catalog contains arcsecond positions and count rates of detected
sources from nearly 3000 public ROSAT HRI observations, including
more than 7500 firm 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 Germany, in the US, and in the UK:
http://wave.xray.mpe.mpg.de/rosat/rra,
http://marlowe.aip.de:8080/~rra/rra.html,
http://heasarc.gsfc.nasa.gov/docs/rosat/rra/RRA.html,
http://hea-www.harvard.edu/rosat/rsdc_www/rra.html,
http://ledas-www.star.le.ac.uk/rosat/rra/.
Access to the command-line driven BROWSE interface to the ROSHRI catalog
is also available via telnet to either legacy.gsfc.nasa.gov
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.
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13. Report on NATO Advanced Study Institute on "The Neutron Star - Black Hole Connection" (Chryssa Kouveliotou, Jan van Paradijs, & Joseph Ventura)
Set against the background of beautiful Mirabello Bay, astronomers from
fourteen countries met at Elounda, Crete in the period 7-18 June,
to debate some of the most compelling issues of present day astrophysics.
Neutron stars and black holes have been at the forefront of
astrophysics for over thirty years. As recently as ten
years ago it was still being debated whether galactic stellar-mass
black holes existed or not. It is now generally accepted that many
(possibly a thousand) stellar-mass black holes -- most of them still
undetected -- lie in low mass X-ray binary (LMXB) systems; a few of them
are detected every year as X-ray or gamma-ray transients. These objects are more
massive than 3 M_sun, the maximum possible mass for a neutron
star, and show none of the tell-tale signs of neutron stars, such as
X-ray bursts and X-ray pulsations.
It is quite remarkable that all LMXBs display a similar temporal and
spectral behaviour, independently of whether the accreting compact
object is a neutron star or a black hole. A broad debate on these
similarities and differences naturally constituted one of the main focal
points during the Elounda meeting. Evidence on these aspects has been
forthcoming from the Compton Gamma-ray Observatory (CGRO), the ROSAT and ASCA
satellites, the Rossi X-Ray Timing Explorer (RXTE), and from
the Beppo-SAX Observatory.
Several reports zeroed in onto the very rich phenomenology of the transient
X-ray source GRS 1915+105, a black hole, also found to be a microquasar
expelling superluminal plasma jets at regular intervals. This source also
displays an interesting pattern of fast spectral and time variations, and
has been singled out as a unique prototype for the study of accretion-disk
instabilities, possibly at work in other accreting black holes.
An observing run of this source with RXTE was
actually taking place while the meeting was
in progress, and a direct internet connection to the experiment
enabled observer Tomaso Belloni to obtain the latest light curves and
variability patterns.
There are indications that we are seeing emission from very close to the black
hole event horizon, possibly at the location of the last stable orbit,
and excitement over the possibility of observing direct manifestations of
general relativity in this and related objects is quite strong.
Predictably, the mysterious gamma ray bursts (GRB), and the recently discovered
magnetars added two more important focal points to the Elounda meeting.
Recent success in following up GRB afterglows has led to identifications
relating these most powerful explosions to faint galaxies at cosmological
distances. It is theorised that these events could be the result of
catastrophic mergers of neutron star binaries, or neutron star - black hole
binaries. Mechanisms leading to such gigantic coalescence events were
reviewed at the meeting.
GRBs are thought to be catastrophic, one-time-only events, resulting in the
total disruption of the initial system. Contrary to these, the distinct class
of the so called soft gamma repeaters (SGRs), numbering only four sources
located in our Galaxy and in the nearby Large Magelanic Cloud, do recur in
sporadic eruptions displaying very soft gamma ray spectra. These objects
have been linked to magnetic neutron stars with rather long, 5 to 10 second
spin periods, and are typically linked to 10^4 year old supernova remnants.
Their long spin periods along with their mesured rates of spin decay point to
ultra-strong magnetic fields of the order of 10^15} Gauss. Are these objects
related to another class of low luminosity - long period X-ray pulsars, known
as anomalous X-ray pulsars? This is still a point of detailed investigation
and debate involving theory and observation.
These, and a multitude of related issues were reviewed, analysed, and
debated in Elounda:
- Can magnetospheric beat frequency models explain some of the
neutron star QPOs?
- QPOs were recently detected during thermonuclear X-ray burst events
in accreting neutron stars. Do these quasiperiodicities relate to the propagation
velocity of burning fronts as they move across the neutron star's surface?
- How is one to interpret the evident similarities of accreting neutron stars
and black holes in low mass X-ray binaries?
- Do NS magnetic fields evolve?
- Do we see the surface thermal emission of isolated neutron stars?
- Do we observe all the neutron stars predicted by the current counts of
supernova events in our Galaxy?
- Which evolutionary senarios give rise to NS and BH binary systems?
- Could a sub-class of GRBs be due to the catastrophic release of the
rotational energy of the neutron star in
some odd, accreting low mass X-ray binaries in distant
galaxies?
All these debates certainly serve in refocussing the observing strategies
to be followed with the new and powerful Chandra and XMM observatories
awaiting launch within this summer.
The Elounda meeting has thus offered an excellent opportunity for
reviewing the capabilities of these and other coming space-borne missions.
One characteristic that made this event memorable to the participants
was the special effort lecturers and speakers placed in preserving a broad
tutorial character in their presentations. This aspect
is specially important in meetings bringing together researchers with very
disparate backgrounds, as it serves in unifying the audience, and furthering
the cross-fertilisation of ideas.
PS: More details on this meeting (program, list of participants) may be
found in the conference web page: http://www.mitos.com.gr/conf/n_starASI99
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14. 2000 HEAD Meeting, Honolulu, Hawaii, November 5-10, 2000
The next meeting of the High Energy Astrophysics Division (HEAD)
of the American Astronomical Society will take place at the
Ilikai Hotel in Honolulu, Hawaii.
Anyone can add their name to the list automatically by sending
any email to: head2k@netcom.com
The above address should be used for any correspondence concerning this
meeting. Details of the meeting, registration and abstract submission
will be distributed by email as they become available. Or you may
contact our website at http://www.eurekasci.com
We look forward to your participation at another successful meeting.
Eureka Scientific
Host, 2000 HEAD Meeting
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15. ROSSI 2000: Astrophysics with the Rossi X-ray Timing Explorer, Greenbelt, Maryland, USA, March 22-24, 2000
As the preeminent large-area X-ray timing mission to date, NASA's
Rossi X-Ray Timing Explorer (RXTE) has proven a powerful and highly
flexible tool for studying the variability of the X-ray sky over a wide
range of time scales and X-ray energies. In order to bring together a
diverse mix of researchers working with RXTE data, we are pleased to
announce "ROSSI 2000", a three day meeting to be held Wednesday
through Friday, March 22-24, 2000, at the NASA Goddard Space Flight
Center in Greenbelt, Maryland, USA. The meeting will focus on the
wealth of rich new data which continues to be collected from the
mission, and it will seek to bring together observers and theorists
studying both Galactic and extragalactic sources in order to explore
the connections between these areas in a broad astrophysical context.
Prospective attendees are encouraged to reply to
rossi2000@lheamail.gsfc.nasa.gov with their name, institution and a
preliminary paper or abstract title.
Tod Strohmayer (NASA/GSFC)
Deepto Chakrabarty (MIT)
Rick Edelson (Leicester/UCLA)
(on behalf of the Scientific Organizing Committee)
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16. CELEBRATE THE MILLENIUM WITH SISTER SOCIETY (APS) (Virginia Trimble)
American Physical Society, 29 April - 2 May, 2000, Long Beach, California
Astrophysics Invited Sessions:
- Saturday AM, The Origin of Cosmic Magnetic Fields
- Saturday PM, The Engine of Gamma Ray Bursters
- Sunday AM, Cosmic Rays: Exploring the extremes
- Sunday PM, First Results from Chandra
- Monday AM, Triumphs of 20th Century Astrophysics
- Tuesday AM, The Women of Stellar Astrophysics
There will also be plenary talks on some astrophysics topics, including
cosmology and extra-solar-system planets.
Contributed talks and posters on these and all other topics within astrophysics
are welcome. The abstract deadline is 14 January, and abstracts can be
submitted via the APS web site, http://abstracts.aps.org. Registration and
housing for the meeting can be arranged through http://www.aps.org/meet/APR00
(those are zero's not oh's).
SPECIAL OPPORTUNITY FOR GRADUATE STUDENTS: Some of the sessions of contributed
talks will feature graduate students reporting on their thesis work, with
partial travel grants for the speakers and a modest award for the best talk.
Encourage your studetns to participate in this unusual opportunity.
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17. INTEGRAL SPRING SCHOOL: "Observing with INTEGRAL + Gamma-Ray Nucleosynthesis"
Les Diablerets, Switzerland, March 29 - April 1, 2000.
A special 4-day school will take place at about 20 months from the launch of
the INTEGRAL gamma-ray Observatory. The purpose of the school is to present and
get familiarized with the Observatory and its instruments. It is open to all of
those who intend to submit an observation proposal to INTEGRAL and/or who
intend to use the data collected by the satellite. It includes presentations on
the INTEGRAL mission, on the instruments and their specifications, and on the
data reduction process. Practical training with computer simulations will also
be provided.
In addition, the school will offer a special nucleosynthesis session dedicated
to GAMMA-RAY RADIOACTIVITY. Those courses complement the 30th Saas-Fee Course,
dedicated to High Energy Astrophysics, which is scheduled at the same location
during the week following the present school.
Further information can be found on: http://isdc.unige.ch/Conf/observing/
E-mail contact: observing@obs.unige.ch
Registration deadline: January 31, 2000
Organizers: T. Courvoisier (thierry.courvoisier@obs.unige.ch),
P. Dourouchoux (durvla@discovery.saclay.cea.fr),
G. Meynet (georges.meynet@obs.unige.ch),
N. Mowlavi (nami.mowlavi@obs.unige.ch),
R. Walter (roland.walter@obs.unige.ch)
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18. 30th SAAS FEE ADVANCED COURSE: "High-Energy Spectroscopic Astrophysics," Les Diablerets, Switzerland, April 3-8, 2000
The Swiss Society for Astrophysics and Astronomy (SSAA) is now organizing
the 30th annual `Saas Fee Advanced Course' in Astronomy and Astrophysics.
The subject of this course will be HIGH-ENERGY SPECTROSCOPIC ASTROPHYSICS.
The course is intended for post-graduate astronomers and astro-/physicists
who wish to broaden their knowledge in this field. The lectures will be
given by three renowned experts in the field:
- Prof. Rashid Sunyaev, on `Hard X-Ray and Gamma-Ray Spectroscopy'
- Prof. Steven Kahn, on `Soft X-Ray Spectroscopy'
- Prof. Peter von Ballmoos, on `Telescope Systems for High-Energy Astrophysics'
Many theoretical, observational, and instrumental aspects will be discussed.
For further details and information on registration (deadline January 31,2000),
visit our website:
http://www.astro.phys.ethz.ch/sf2000/
e-mail contact: sf2000@obs.unige.ch
Course Organizers:
Roland Walter,
Integral Science Data Center,
CH-1290 Versoix,
Switzerland,
Roland.Walter@obs.unige.ch and
Manuel Guedel,
Paul Scherrer Institute,
CH-5232 Villigen PSI,
Switzerland,
guedel@astro.phys.ethz.ch.
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19. 4th INTEGRAL Workshop: Exploring the Gamma-ray Universe, Aula de Cultura (CAM) Alicante, Spain, September 4-8, 2000
The 4th INTEGRAL (International Gamma-Ray Astrophysics Laboratory) workshop
`Exploring the Gamma-ray Universe' will take place from 4 - 8 September
2000 in Alicante, Spain.
The workshop is being jointly sponsored by ESA, NASA, INTA, CDTI, CICYT, Caja de Ahorros del Mediterraneo, The Generalitat Valenciana and some of the main european aerospace companies.
This circular calls for contributed oral and poster papers to be presented
at the workshop.
Registration and hotel accommodation forms, instructions for authors and
kits for the preparation of abstracts (including examples)
will be available via the WWW pages of the Local Organizing Committee (LOC):
http://www.integral.ua.es
The ESA INTEGRAL pages on the WWW will also provide access to the
latest workshop information:
http://astro.estec.esa.nl/SA-general/Projects/Integral/integral.html
It is intended to make all accepted abstracts and the scientific programme
information available on the WWW. The deadline for receipt of abstracts is
15 March 2000.
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20. Inst. for Theoretical Physics program for Fall 2000: ``Spin and Magnetism in Young Neutron Stars,'' University of California, Santa Barbara
A long-term program entitled ``Spin and Magnetism in Young Neutron
Stars'' will be held at the Institute for Theoretical Physics (ITP) at
the University of California, Santa Barbara, from July 31, 2000 to
December 15, 2000. A one week conference will be held October 2-6,
2000 at the ITP. The program coordinators are Lars Bildsten, Lars
Hernquist, Vicky Kaspi and Shri Kulkarni.
The recent discoveries of highly magnetized neutron stars and new
physical mechanisms that might set the initial neutron star rotation
rate has given us exciting new insights into neutron star properties
and forces us to reconsider much of the interior physics of these
extreme stellar remnants. The intent of this program is to bring
together researchers working on all aspects of neutron star properties
set during their birth and prevalent during their youth. This will
include the origin of magnetism and the high-field magnetars, the
possible role of gravitational radiation in limiting the initial spin
periods, the origin of kicks and glitches and new information from
neutron star cooling. The rapid observational progress on these
topics (both from current and future X-ray satellites, as well as
radio pulsar surveys) makes the time ripe for a gathering of theorists
and observers.
Theoretical focus will be placed on the interior physics of the
neutron star as well as physics during the collapse, the role of
progenitor evolution, atmospheric modeling and cooling spectra, and
most importantly the interpretation of the rapidly arriving datasets.
The observational progress on these topics (both from current and
future X-ray satellites, as well as radio pulsar surveys) makes the
time ripe for a gathering of theorists and observers. Indeed, this
program will provide an opportunity to reconsider the theoretical
interpretations of the observations and the resulting implications for
the inferred properties of the young neutron star. It is hoped that
collaborations and new research directions will emerge from the
extended interactions between theorists interested in the physics of
neutron stars with both the observers and the general relativists
working on gravitational wave emission from young neutron stars.
We also hope to have observers present who can present in some
detail the status of current observational work, emphasizing what they
consider to be future directions, thus stimulating theoretical work of
broad relevance. The parallel program at the ITP during the same
period is "High Temperature Superconductivity'" (organized by
C. Kallin, R. Laughlin, P. Lee, and D. Scalapino) so the theoretical
overlap should be large for interior physics, superfluids and
superconductivity.
If you would like more information, please do not hesitate to
contact any of the coordinators. More information on both the program
and the conference can be found at the ITP website (www.itp.ucsb.edu)
Lars Bildsten, ITP; Lars Hernquist, Harvard; Vicky Kaspi, MIT;
Shri Kulkarni, Caltech
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21. 33rd COSPAR Scientific Assembly, Warsaw, Poland, July 16-23, 2000
The 33rd COSPAR Scientific Assembly in Warsaw, Poland, which will take
place during the week of 16-23 July, 2000, will feature several symposia of
interest to HEAD members. Detailed meeting information can be obtained at
http://www.copernicus.org/COSPAR/COSPAR.html
The website does not yet contain the list of confirmed invited speakers,
but it does contain an abstract about each of the various 1-2 day symposia
at the assembly. Individual abstracts are due 10 January 2000.
Among the symposia of that may be of interest to HEAD members are:
- "X-Ray and Gamma-Ray Signatures of Black Holes and Weakly Magnetized
Neutron Stars" (organized by Andrzej Zdziarski)
- "Origin and Acceleration of Cosmic Rays" (organized by Mark Wiedenbeck)
- "New Vistas from X-Ray Observatories" (organized by Steve Holt)
The latter 2-day symposium will be the first opportunity for coordinated
results from Chandra, XMM and Astro-E to be presented. It's confirmed list
of invited speakers is:
- Session 1: The Extragalactic Scale
- Martin Weisskopf Chandra Introduction/Status
- Fred Jansen XMM Introduction/Status
- Hajime Inoue Astro-E Introduction/Status
- Andy Fabian Spectroscopy of Clusters
- Richard Mushotzky Dark Matter from Clusters
- Session 2: The Galactic Scale
- Giuseppina Fabbiano Imaging Studies of Galaxies
- Kazuo Makashima Spectoscopy of Normal Galaxies
- Chris Reynolds Reverberation Studies of AGN
- Hideyo Kunieda Spectroscopy of AGN
- Session 3: The Nebular Scale
- Steve Kahn Characterization of Sources in the LMC
- Rob Petre Imaging of SNR
- Jack Hughes Spectroscopic Studies of SNR
- Eric Feigelson Star Forming Regions
- Session 4: The Stellar Scale
- Manuel Guedel Spectroscopic Studies of Stars
- Richard Kelley Spectroscopic Studies of X-ray Binaries
- Koji Mukai Spectroscopic Studies of Cataclysmic Variables
- Werner Becker X-ray Observations of Pulsars
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HEADNEWS, the electronic newsletter of the High Energy Astrophysics Division of the
American Astronomical Society, is issued by the Secretary-Treasurer, at the Department of
Astronomy, Boston University, 725 Commonwealth Ave., Boston, MA 02215. The HEAD Executive
Committee Members are:
