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. ********************************************************************* FIRST ANNOUNCEMENT ********************************************************************* 3rd HUNTSVILLE SYMPOSIUM ON GAMMA-RAY BURSTS ********************************************************************* PLACE: Huntsville, Alabama USA TIME: October 25-27, 1995 ********************************************************************* 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 ********************************************************************* 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 *********************************************************************