Compton Observatory Science Report #137 Thursday, September 30, 1993 Eric Chipman, Compton Observatory Science Support Center Questions or comments can be sent to the Compton SSC. Phone 301/286-7764, e-mail SPAN GROSSC::CHIPMAN, Internet chipman@grossc.gsfc.nasa.gov. Correction: The name of the latest Target of Opportunity source that was observed from Sept 21 to Sept 22 was garbled in last week's report. The correct name is GRS 1009-45. Science operations are continuing. Operations to prepare for next Monday's start of the reboost are underway, with a maneuver to to reboost attitude scheduled for Friday, October 1. It has been decided that the spacecraft will not be re-oriented for observations of the source GRO J1719-24 (see BATSE report below). ARCHIVES -------- Archive contents- BATSE - Bursts to trigger 1466, flares to trigger 884, four months of daily HER and SHER data. Additional flare data up to trigger 1466 and corresponding HER and SHER data has been received at the SSC and is being installed in the archive. Some high-level pulsar light curves have been received at the SSC COMPTEL - Periods 1-13 are available Egret - Periods 0.2-30 are available (Maps and photon lists) OSSE - Periods 0.2-13 (minus pd 3) are available (SDB data). Pulsar data also available off-line. BATSE ----- The following has been submitted as an IAU Circular: GRO J1719-24 B. A. Harmon, NASA/Marshall Space Flight Center, S. N. Zhang, Universities Space Research Association, W. S. Paciesas, University of Alabama, Huntsville, and G. J. Fishman, NASA/Marshall Space Flight Center, report for the Compton Observatory/BATSE Team: A new hard x-ray transient has been discovered using Earth occultation monitoring on September 25 in the energy range 20-320 keV. Its location is R.A. = 17h19.2m Dec.=-24d24m with 1-sigma error box with the following corners R.A., Dec. = 17h24.4m, -26d12m; 17h17.6m, -24d30m; 17h11.2m, -21d18m; 17h20m,-24d0m. The spectrum is hard, with power law number index -2.0 in the 20-100 keV band; however, the broad-band spectrum is better fit with a thermal bremsstrahlung model with temperature kT = 70-100 keV. The temperature decreases with increasing intensity. The light curve shows the source becoming visible late on Sept 24, with the following average intensities relative to the Crab (20-100 keV); +/- 20%): Sept 24: 0.07, Sept 25: 0.46, Sept 26: 0.82, Sept 27: 1.1, Sept 28: 1.2. Fast intensity variations (~seconds) are also observed. Monitoring of the source is continuing. During viewing period 303.4 and 303.5 BATSE folded-on-board pulsar data will be collected for the Crab Pulsar, PSR 0525+21, PSR 1259-63, and PSR 0835-41. The pulsar hardware will also be used to collect 31 ms resolution single sweep data for power spectral analyses of GRO J1719-24. COMPTEL ------- The COMPTEL instrument is performing well and continues routine observations. In anticipation of the orbital reboost of the GRO spacecraft, scheduled to begin on Monday, the COMPTEL instrument will be placed in a low-power mode on Friday, 1 October. COMPTEL will remain "off" for the duration of the reboost maneuver. Among the scientific results presented by the collaboration last week at the 2nd Compton Symposium in Maryland were exciting reports on diffuse gamma-ray line emission observed by COMPTEL. Bloemen et al. reported the detection of intense gamma-ray emission from the Orion complex in the 3-7 MeV range, which can be identified with the cosmic-ray induced 4.44 and 6.13 MeV nuclear de-excitation lines of carbon and oxygen. Iyudin et al. presented the detection of line emission from the Cas A supernova remnant at 1.15 MeV, originating from the decay of 44Ti. A status report on the mapping of the 1.8 MeV radiation from 26Al in the Galactic plane by R. Diehl showed increasing evidence for highly structured emission, including a particularly interesting excess in the Vela region. These findings were generally considered to be a real breakthrough in gamma-ray line spectroscopy. The importance of COMPTEL observations of AGNs was illustrated by Blom et al., Collmar et al., and Maisack et al. Presentations by McConnell et al. and van Dijk et al. showed COMPTEL's latest results on Galactic compact sources (Cyg X-1, Nova Persei, and 2CG135). Hermsen et al. presented the preliminary results of a GRO-wide monitoring of WR140 during its periastron passage. The reviews by J. Ryan and A. Strong included the latest results of COMPTEL observations of the Sun and the diffuse Galactic emission, respectively. EGRET ----- EGRET operations were normal this week. The current observation period ends tomorrow and detailed preparations have been made for the reboost period. The generally low value of short observations for EGRET has been noted before. This statement has certainly been true in Phase 2; we hope they can be avoided in Phase 3. Seth Digel, a Compton Observatory fellowship winner, has now joined us to work on his project. We continue to have a healthy number of guest investigators visiting us. OSSE ---- OSSE operations have returned to normal. The cause of the two lock-ups last week has been traced to a subtle bug in flight software we introduced in a recent update. We have removed the offending code and corrected the software update. For the brief pointing before the reboost interval, the Z-axis target is Cyg X-1, and the X-axis target is 3C 273. The Sun is near the OSSE scan plane, so the slewing response to BATSE solar flare triggers is enabled. There have been no slews since the last report. For the reboost period, OSSE will be placed in a low-power mode each day on which a boost occurs, then restored to safehold mode after operations settle down. On days on which there is no orbit boost, we plan a series of science and engineering tests. Data from viewing period 14 will be delivered today to the Compton GRO Science Support Center Archive. Targets during this period were the Galactic Center region and Eta Car. Other Items: ------------ For the interest of those working with Phase 2 data, the final Phase 2 Viewing Plan is attached. The last observations of Phase 2 were completed on September 7. 8/5/93 COMPTON PHASE 2 VIEWING PLAN AS OF AUGUST 5, 1993 GRO Z-AXIS* VIEW +Z-AXIS* GRO Z-AXIS* GALACTIC GRO X-AXIS* ----OSSE PRIMARY TARGET---- ----OSSE SECONDARY TARGET-- PER. START TARGET RA DEC LONG LAT RA DEC TARGET RA DEC TARGET RA DEC --------------------------------------------------------------------------------------------------------------------------------- 201 11/17/92 HER X-1 253.15 42.26 66.79 39.28 266.02 -47.01 HER X-1 254.46 35.34 G PLANE 355 263.30 -33.17 202 11/24/92 HER X-1 251.55 45.40 70.85 40.50 270.04 -43.08 HER X-1 254.46 35.34 G CENTER 266.40 -28.94 203.0 12/01/92 CYGNUS 306.59 39.34 77.85 0.69 258.44 -39.15 CYG X-1 299.59 35.21 G CENTER 266.40 -28.94 203.3 12/08/92 CYGNUS 306.59 39.34 77.85 0.69 264.05 -41.96 CYG X-1 299.59 35.21 G CENTER 266.40 -28.94 203.6 12/15/92 CYGNUS 306.59 39.34 77.85 0.69 258.44 -39.15 CYG X-1 299.59 35.21 G CENTER 266.40 -28.94 204 12/22/92 3C 273 188.99 -0.74 294.70 61.88 279.50 -34.03 3C 273 187.28 2.05 G PLANE 355 263.30 -33.17 205 12/29/92 3C 273 188.84 -1.03 294.47 61.58 279.32 -24.79 3C 273 187.28 2.05 G PLANE 5 269.27 -24.64 206 01/05/93 3C 273 188.99 -0.74 294.70 61.88 279.50 -34.30 3C 273 187.28 2.05 G PLANE 355 263.30 -33.17 207 01/12/93 IC 4329A 203.86 -30.41 314.06 31.51 293.35 0.86 IC 4329A 207.33 -30.31 PSR 1822-09 276.25 -9.00 208 02/02/93 NGC 4507 198.47 -41.93 307.39 20.75 296.86 -9.24 NGC 4507 188.90 -39.91 NGC 6814 295.67 -10.31 209 02/09/93 2CG 010-31 305.69 -40.81 0.24 -34.01 297.95 48.93 2CG 010-31 304.75 -31.84 3C 390.3 280.56 79.76 210 02/22/93 GAL CENTER 257.65 -29.10 355.62 6.28 351.03 -6.03 1E 1740-2942 265.98 -29.72 MCG -2-58-22 346.18 -8.69 211 02/25/93 GAL 123-05 18.38 58.05 125.86 -4.70 8.08 -31.53 4U 0115+634 19.86 62.49 47 TUC 5.83 -72.07 212 03/09/93 WR 140 298.65 50.54 84.33 11.43 341.61 -31.07 WR 140 305.12 43.85 NGC 7314 338.94 -26.05 213 03/23/93 CRAB PULSAR 80.30 22.29 182.63 -8.22 348.47 4.44 CRAB PULSAR 83.52 22.02 MRK 509 311.04 -10.72 214 03/29/93 GAL CENTER 257.65 -29.10 355.62 6.28 351.03 -6.03 1E 1740-2942 265.98 -29.72 MCG -2-58-22 346.18 -8.69 215 04/01/93 CEN A 203.26 -39.28 311.66 22.89 53.56 -46.55 CEN A 201.37 -43.02 SN 1987A 83.86 -69.27 216 04/06/93 SN 1993J 143.64 71.46 140.75 38.11 3.37 14.47 SN 1993J 148.84 69.02 M31 10.68 41.27 217 04/12/93 CEN A 203.26 -39.28 311.66 22.89 53.56 -46.55 CEN A 201.37 -43.02 SN 1987A 83.86 -69.27 218 04/20/93 NGC 4151 180.75 43.09 151.41 71.26 31.04 42.71 SN 1993J 148.84 69.02 NGC 4151 182.64 39.41 219.1 05/04/93 REBOOST THRUSTER TESTING 219.4 05/05/93 GAL CENTER 245.35 -27.22 350.10 15.86 341.26 -11.31 1E 1740-2942 265.98 -29.72 MCG -2-58-22 346.18 -8.69 219.7 05/07/93 REBOOST CALIBRATION BURN 220 05/08/93 SMC 24.11 -72.07 298.09 -44.63 69.97 12.70 SMC X-1 19.18 -73.44 3C 120 68.30 5.35 221 05/13/93 CRAB PULSAR 85.21 19.46 187.52 -5.88 326.68 53.49 CRAB PULSAR 83.52 22.02 PSR 1951+32 298.24 32.89 222 05/24/93 NGC 4151 178.02 42.25 157.79 70.63 60.65 26.85 NGC 4151 182.64 39.41 MCG +8-11-11 88.73 46.44 223 05/31/93 GAL CENTER 265.98 -29.72 359.14 -0.09 316.33 48.19 1E 1740-2942 265.98 -29.72 CYG X-3 308.11 40.96 224 06/03/93 SMC 24.11 -72.07 298.09 -44.63 69.97 12.70 SMC X-1 19.18 -73.44 3C 120 68.30 5.35 225 06/15/93 REBOOST 226 06/19/93 GAL 355+05 258.44 -30.35 355.00 5.00 189.52 31.57 G CENTER 266.40 -28.94 COMA CLUSTER 194.90 27.96 227 06/28/93 SN 1993J 143.64 65.00 148.11 41.22 116.97 -22.62 SN 1993J 148.84 69.02 PSR 0740-28 115.71 -28.38 228 07/13/93 SN 1993J 145.33 63.18 149.85 42.69 131.74 -26.16 SN 1993J 148.84 69.02 VELA PULSAR 128.92 -45.18 230 07/27/93 VELA REGION 143.03 -54.64 276.66 -2.27 127.10 34.31 GRO J1008-57 145.00 -59.00 QSO 0716+714 110.48 71.34 230.5 07/30/93 VELA REGION 149.86 -53.17 278.79 1.44 131.53 35.41 GRO J1008-57 145.00 -59.00 QSO 0716+714 110.48 71.34 231 08/03/93 NGC 6814 289.94 -15.33 22.22 -13.08 186.93 -39.38 NGC 6814 295.67 -10.31 NGC 4507 188.90 -39.91 229 08/10/93 GAL 5+05 264.60 -22.06 5.00 5.00 188.59 30.82 G CENTER 266.40 -28.94 COMA CLUSTER 194.90 27.96 229.3 08/11/93 PERSEID METEOR SHOWER 229.5 08/12/93 GAL 5+05 264.60 -22.06 5.00 5.00 188.59 30.82 G CENTER 266.40 -28.94 COMA CLUSTER 194.90 27.96 301** 08/17/93 VELA PULSAR 128.92 -45.18 263.59 -2.74 161.94 39.80 VELA PULSAR 128.92 -45.18 QSO 1028+313 157.74 31.05 232 08/24/93 GAL 348+00 258.02 -39.35 347.50 0.00 188.46 23.07 GPLANE 347.5 258.02 -39.35 MRK 421 166.11 38.21 232.5 08/26/93 GAL 348+00 258.02 -39.35 347.50 0.00 182.10 16.48 GPLANE 347.5 258.02 -39.35 NGC 4388 186.44 12.66 09/07/93 end Phase 2 ** Phase 3 target * Z-axis is pointing direction for COMPTEL and EGRET. OSSE points in X-Z plane. RA and DEC are J2000.