CGRO biWeekly Status Report

[SHRADER@GROSSC.GSFC.NASA.GOV]

 Compton Observatory Science Report #176, Thursday February 2, 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
                                                                     

                     Science Support Center News

The committee meeting to determine the final evaluation of the CGRO
fellowship proposals will occur next week. We anticipate contacting
most proposers by mid-February with the results of the review. In the
meantime if it is sufficiently urgent, candidates who have other
pending job offers should contact the SSC for more information. 

The software for the electronic submission of Cycle-4 proposal forms
is now available. There are two methods, one involves editing an
ascii file and then e-mailing it to a special account on one of the
SSC computers. To get instructions on how to do this, just send a
blank message to rps@cossc.gsfc.nasa.gov == cossc::rps. 

The other methods, which may appeal to those among you who are more
visually oriented, uses the Xmosaic interface to the World-Wide Web.
Just open the CGRO-SSC homepage:
http://cossc.gsfc.nasa.gov/cossc/cossc.html,
scroll down a bit to "Remote Proposal Submitter (RPS)" option, then
point and click. This will bring up a screen that looks similar to
the actual forms, as well as a help item.

In either approach, you run your completed form through a
verification procedure until the software is happy. You can download
printable (LaTeX) versions of your completed (or partially completed)
forms for your own inspection. You then choose a submit option, which
sends the data in to our database and gives you the final hard copy
to attach to your proposal for paper submission.


                         Instrument Reports

EGRET

EGRET operations were normal this biweekly period. Delivery of data
to the GRO SSC remains on schedule. Interaction with guest
investigators continues at a good level.

A paper by Mukerherjee et al.  on unidentified sources in the
galactic plane has just been accepted by the Astrophysical Journal. 
Another paper on high luminosity flat spectrum radio quasars that
have not been seen in high energy gamma rays by EGRET has also been
accepted by the Astrophysical Journal. The Hamburg COSPAR 94 papers
have just appeared in Adv. Space Research Vol 15, No 4.

At the moment, EGRET is viewing a region of the sky at intermediate
galactic latitudes centered at ( l=82.2o, b=-32.6o).



OSSE

OSSE operations are normal.  In particular, the motor drive for
detector #1 continues to operate flawlessly.

As of 30 January, we have disabled the slewing response to BATSE
burst triggers.  BATSE has changed its trigger to the 25-100 keV
band, and it is likely that the rate of false (i.e. particle-induced)
slewable triggers will increase.  We will re-enable the slewing when
the test period ends.

In viewing period 410 (24 Jan - 14 Feb), the Z-axis target is XB
1916-053 (Guest Investigator D. Barret), and the X-axis targets are
GRS 1716-249 (PI team) and IC 4329A (Guest Investigator G. Madejski). 
When these objects are occulted by the Earth, the target is Mrk 348.

Data from viewing periods 304 and 305 were delivered to the Compton
GRO Science Support Center archive this week.  The targets during
these viewing periods were the Virgo region sky survey, GRS 1716-249,
and the galactic plane near (l,b) = (5,0).
 

COMPTEL

The COMPTEL instrument is performing well and continues routine
observations.

Several more preprints on recent COMPTEL results have just been
distributed by the collaboration.  These reports include
"Simultaneous and Quasi-simultaneous Observations of the Continuum
Emission of the Quasar 3C 273 from Radio to Gamma-Ray Energies"
(Lichti et al.), "COMPTEL Observations of Galactic 26-Aluminum
Emission" (Diehl et al.), and "Upper Limits on the MeV Emission of
Seyfert Galaxies" (Maisack et al.), all currently in press in
Astronomy & Astrophysics, as well as a collection of the COMPTEL
papers presented at the COSPAR Gamma-Ray Astronomy Symposium in
Hamburg, Germany (July 1994).

The *preliminary* programme (including Abstracts) of the upcoming
ESLAB symposium "Towards the Source of Gamma Ray Bursts" may now be
accessed on the World Wide Web at the following URL:
'http://astro.estec.esa.nl/SA-general/sasymposia.html' The third and
final announcement for the symposium, already available at the above
Web site, will be mailed soon.  The organizers urge you to register
and make your hotel reservations early as the popularity of the
symposium far exceeds expectations.


BATSE


The following report was included in IAUC 6128:

     X-RAY NOVA IN SCORPIUS

     B. A. Harmon, S. N. Zhang, G. J. Fishman, C. A. Wilson, W. S.
     Paciesas, and B. C. Rubin, report for the Compton Gamma Ray
     Observatory BATSE Team: "This object (GRO J1655-40) has become
     detectable again, varying between 150-250 mCrab in the band
     20-100 keV since Jan. 12. The previous hard x-ray outburst (IAUC
     6101, 6106) ended in late December 1994. Emission is seen to at
     least 200 keV."

The BATSE on-board burst trigger criterion has been changed
temporarily to be  more sensitive to soft gamma-ray repeaters (SGR's)
and other soft, transient  sources in support of a Guest
Investigation by C. Kouveliotou et al. The  energy  range of
detection will be 25keV to 100keV.  This change will result in 
reduced sensitivity to classical GRB's and terrestrial gamma-ray
flashes. 

Enhanced sensitivity to terrestrial gamma-ray flashes was provided by
the trigger criterion used during the 135 days from September 19 1994
to January 31 1995. This trigger was based on the rates above 100
keV. Fifteen terrestrial gamma-ray flashes were detected as compared
to 20 in the previous three years. This high energy triggering
criterion will occasionally be briefly resumed to attempt coordinated
observations of atmospheric gamma-ray flashes.

The following sources were detected by the BATSE pulsed source
monitor in the past two weeks: Cen X-3, 4U 1626-67, 2S 1417+624, OAO
1657-415, GX 1+4, Vela X-1, and GX 301-2. 2S 1417+624 was visible 
from January 4 to January 25.

As of February 1, BATSE has detected 1220 cosmic gamma-ray bursts out
of a total of 3284 on-board triggers in 1380 days of operation. There
have been 741 triggers due to solar flares with emission above 60
keV. There have been 35 triggers due to terrestrial gamma-ray flashes
since the beginning of the mission.


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               FIRST ANNOUNCEMENT 
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          3rd HUNTSVILLE SYMPOSIUM ON GAMMA-RAY BURSTS

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PLACE:  Huntsville, Alabama USA

TIME:   October 25-27, 1995

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Scientific Organizing Committee: 

M. Briggs, UAH
G. Fishman, MSFC
J. Greiner, MPE
D. Hartmann, Clemson
C. Kouveliotou, USRA - Chairman
I. Mitrofanov, IKI
T. Murakami, ISAS
R. Nemiroff, GMU

Local Organizing Committee:

S. Aldridge, USRA
S. Belefield, USRA
M. Briggs, UAH
P. Cushman, USRA
G. Fishman, MSFC
C. Kouveliotou, USRA 

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To receive future announcements contact:

USRA- Attn: Susan Belefield- Suite 100, 4950 Corporate Drive N.W.,
Huntsville, Al 35806, USA
FAX: 205 - 895 9222
NSI-DECNET:  batse::workshop  NSI:  workshop@batse.msfc.nasa.gov
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