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CGRO Monthly Status Report

    Compton Observatory Science Report #182, Tuesday, June 9 1995
      Chris Shrader, Compton Observatory Science Support Center

         Questions or comments can be sent to the CGRO SSC.
          Phone:    301/286-8434
          e-mail:   NSI_DECnet: GROSSC::SHRADER 
          Internet: shrader@grossc.gsfc.nasa.gov

                       Guest Investigator News

The Cycle-5 Proposal Review was held two weeks ago. The time-line
committee meeting will occur later this month, after which all
proposers will be notified of the peer-review evaluation of their
proposals - hopefully letters will go out in the mid-July time frame.

As noted in some of the Instrument Team reports, the Third Compton
Symposium will be held in Munich, Germany next week - many exciting
results are expected.

Copies of a preprint entitled "Recent Results From the Compton Gamma
Ray Observatory", are available from the GRO-SSC (contact Sandy
Barnes at barnes@grossc.gsfc.nasa.gov). The article will appear in
the July issue of PASP (It will also be available electronically
shortly - today if I get a late burst of energy).

Need help regarding CGRO analysis software, data, or policy issues???
There is now a mail exploder called grohelp, through which your
questions will get promptly distributed to the appropriate person(s)
for expeditious response. Just send e-mail to

Congratulations to Jerry Fishman, who will present the Rossi Prize
Lecture at the Pittsburgh AAS Meeting next week, and to Jay Norris 
will receive Goddard Space Flight Center's Annual Lindsay Prize award
at this afternoon's colloquium. Both Jerry and Jay are honored for
their work on Gamma-Ray Burst research.

                         Instrument Reports


EGRET operations were normal this monthly period.  Delivery of the
final phase 3 data to the GRO SSC remains on schedule and delivery of
the phase 4 preliminary data to the GRO SSC is now running ahead of 
schedule. Interaction with guests investigators continues at a good

The Second EGRET Catalog of High Energy Gamma-Ray Sources has been
accepted by the Astrophysical Journal Supplement, and preprints are
being mailed to the standard mailing list.  There are now over fifty
AGN identifications among the sources in the catalog.  There are also
approximate upper limits for gamma-ray sources at any point in the
sky. The catalog uses an improved model of the diffuse galactic gamma
radiation, which is now available through the GRO SSC.  The catalog
tables are available by anonymous ftp from gamma.gsfc.nasa.gov,
subdirectory pub/second-catalog. The format is plain ASCII.  The
figures, including the full set of source location maps, are also
available in PostScript format at this same location.  The map of
upper limits for any point in the sky is available in FITS format.

There has also been a detection of another puslar, PSR B1951+32.  A
paper on this topic by Ramanamurthy et al. has been accepted by the
Astrophysical Journal.  Another paper, also accepted by the
Astrophysical Journal, is concerned with a long term study of high
energy gamma-ray emission from Vela, Geminga, and Crab pulsars. 
Preprints of these last two papers also exist and are being mailed to
the standard mailing list.

An observation of the Galactic center region has just begun and will
continue through July 4, 1995.


OSSE operations are normal. Detector motor drive #1 continues to
operate without error. Since 10 April, the slewing response to BATSE
burst triggers  has been disabled, since the BATSE burst trigger is
set to the low energy (25-100 keV) band.

An OSSE paper on PSR 1259-63 (Grove et al. ApJL) has recently been
accepted. The observed unpulsed power law emission near periastron,
consistent with an  extrapolation of contemporaneous ASCA data, is
the first strong evidence for shock-powered emission in a binary

OSSE team members are preparing a large number of presentations for
next week's Compton Symposium, including summaries of the results of
the just completed searches for lines from Cas A and the Orion

Recent observations are listed in the following table.

View period    Dates          Target (owner)
    419.5      9-23 May       Orion A+B (GI H. Bloemen)
                              Cas A (PI team)
    420        23 May - 6 Jun Orion A+B (GI: H.Bloemen)
                              Cas A (PI team)
    421        6-13 Jun       Gal plane (355,0) (PI team)
                              SMC X-1 (PI team)

Data from viewing periods 318.1, 321.1, 321.5, 317, and 319.0 were
delivered to the Compton GRO Science Support Center archive in the
last month.  The targets during these periods were Cyg X-1, NGC 253,
A0535+26, PSR 0540-69, 3C120, CTA 102, QSO 0716+714, and PKS


The COMPTEL instrument is performing well and continues routine

The following papers by the collaboration are currently in press.
Most have recently been distributed as preprints, and will also soon
be available as postscript documents via either anonymous ftp from
unhgro.unh.edu (cd to the pub/papers directory), or via the COMPTEL
WWW pages accessible from the COSSC home page (at URL
http://cossc.gsfc.nasa.gov/cossc/cossc.html).  "COMPTEL detection of
two spatially-coincident gamma-ray bursts" (Kippen et al.); "COMPTEL
search for 22-Na emission from recent novae" (Iyudin et al.); "The
gamma-ray burst GB 920622" (Greiner et al.); all of the above will
appear in Astronomy and Astrophysics.  In addition, a review paper on
"Radioactive 26-Al in the Galaxy: Observations vs Theory" (Prantzos
and Diehl) will appear in Physics Reports.

The collaboration has recently forwarded to the COSSC public data
archive at the NASA/GSFC low-level and first high-level COMPTEL data
products for the CGRO viewing periods 301 to 313 inclusive.

There will be presentations by members of the collaboration at the
June meeting of the Solar Physics Division of the AAS in Memphis, and
the general meeting of the AAS in Pittsburgh. Numerous team reports
will also be presented at the Third Compton Symposium next week in
Munich, for which final preparations are nearing completion.  A
semi-final program of the agenda has recently been distributed.  The
latest information regarding the Symposium can be found at the
following URL on the Web:


Several BATSE team scientists will be presented papers at the 3rd
Compton Symposium in Munich. Bill Paciesas will be giving a BATSE
overview, and present observations of GRS 1915+105. David Crary will
present a long term power spectral study of Cyg X-1. Mark Finger will
present a study of the resent outburst of the x-ray binary 2S
1417-624. Nan Zhang will present observations of the burster 4U
1608-522, and the newly discovered x-ray binary GRO J1849-03. 

Jerry Fishman will be receiving the Rossi Prize at the AAS meeting in
Pittsburgh. At the meeting, talks or posters will be given by Tom
Kosshut, Geoff Pendleton, Chyssa Kouveliotou, and Bob Mallozzi. 

Several papers by members of the BATSE burst have been accepted 
for publication:

"Do Gamma-Ray Burst Sources Repeat?" by C.A. Meegan, D. Hartmann, J.
Brainerd, M.S. Briggs, W.S. Paciesas, G.N. Pendleton, C. Kouveliotou,
G.J. Fishman,  G. Blumenthal, and M. Brock, will appear in the June
10 issue of ApJ. 

"Gamma-ray Burst Precursor Activity As Observed With BATSE" by T.M.
Koshut,  C. Kouveliotou, W.S. Paciesas, J. van Paradijs, G.N.
Pendleton,  M.S. Briggs, G.J. Fishman, and C.A. Meegan will appear in
the  Oct 10 issue of ApJ. 

"Galactic Gamma-ray burst Models: Constraints on the Intrinsic
Luminosity  Function" by J. Hakkila, C.A. Meegan, G.N. Pendleton,
J.M. Horack,  M.S. Briggs, W.S. Paciesas and A.G. Emslie, will appear
in the  November 20 issue of ApJ. 

The following sources have been detected by the BATSE pulsed source
monitor since April 1st : Her X-1, Cen X-3, 4U 1626-67, 2S 1417-624,
OAO 1657-415, GX 1+4, Vela X-1, and GX 301-2. 

To provide enhanced sensitivity to soft gamma-ray repeaters the BATSE
burst trigger has operated on the 25-100 keV energy range since April

As of TJD June 8th BATSE has detected 1296 gamma-ray bursts out of a
total of 3527 on-board triggers in 1507 days of operation. There have
been 757 triggers due to solar flares with emission above 60 keV, 9
due to SGR events, and 48 due to terrestrial gamma-ray flashes.