Gamma-ray Burst 090916

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 16 Sep 09 07:14:15 UT
  NOTICE_TYPE:     Swift-BAT GRB Position
  TRIGGER_NUM:     362818,   Seg_Num: 0
  GRB_RA:          126.579d {+08h 26m 19s} (J2000),
                   126.725d {+08h 26m 54s} (current),
                   125.829d {+08h 23m 19s} (1950)
  GRB_DEC:         +25.933d {+25d 55' 60"} (J2000),
                   +25.901d {+25d 54' 03"} (current),
                   +26.098d {+26d 05' 52"} (1950)
  GRB_ERROR:       3.00 [arcmin radius, statistical only]
  GRB_INTEN:       1205 [cnts]    Image_Peak=83 [image_cnts]
  TRIGGER_DUR:     0.256 [sec] 
  TRIGGER_INDEX:   123     E_range: 25-100 keV
  BKG_INTEN:       23415 [cnts]
  BKG_TIME:        25234.91 SOD {07:00:34.91} UT
  BKG_DUR:         8 [sec]
  GRB_DATE:        15090 TJD;   259 DOY;   09/09/16
  GRB_TIME:        25244.12 SOD {07:00:44.12} UT
  GRB_PHI:         -11.26 [deg]
  GRB_THETA:        48.16 [deg]
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     16.37 [sigma]
  IMAGE_SIGNIF:    7.61 [sigma]
  MERIT_PARAMS:     +1  +0  +0  -2  +2  -2  -5  +0 -62  +0 
  SUN_POSTN:       174.08d {+11h 36m 20s}   +2.56d {+02d 33' 29"}
  SUN_DIST:         51.08 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
  MOON_POSTN:      141.57d {+09h 26m 18s}  +13.05d {+13d 02' 49"}
  MOON_DIST:        18.97 [deg]
  MOON_ILLUM:      8 [%]
  GAL_COORDS:      197.70, 31.42 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      122.65,  6.54 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        SWIFT-BAT GRB Coordinates.  
  COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trigger integration interval;  
  COMMENTS:        probably due to it occurring during a Malindi downlink session.  
  COMMENTS:        This is a rate trigger.  
  COMMENTS:        A point_source was found.  
  COMMENTS:        This does not match any source in the on-board catalog.  
  COMMENTS:        This does not match any source in the ground catalog.  
  COMMENTS:        This is a GRB.  
  COMMENTS:        This trigger occurred at longitude,latitude = 11.84,1.15 [deg].  
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 16 Sep 09 07:14:40 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     362818,   Seg_Num: 0
  GRB_RA:          126.579d {+08h 26m 19s} (J2000),
                   126.725d {+08h 26m 54s} (current),
                   125.829d {+08h 23m 19s} (1950)
  GRB_DEC:         +25.933d {+25d 55' 60"} (J2000),
                   +25.901d {+25d 54' 03"} (current),
                   +26.098d {+26d 05' 52"} (1950)
  GRB_DATE:        15090 TJD;   259 DOY;   09/09/16
  GRB_TIME:        25244.12 SOD {07:00:44.12} UT
  TRIGGER_INDEX:   123
  GRB_PHI:         -11.26 [deg]
  GRB_THETA:        48.16 [deg]
  DELTA_TIME:      38.00 [sec]
  TRIGGER_DUR:     0.256 [sec] 
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     16.37 [sigma]
  IMAGE_SIGNIF:    7.61 [sigma]
  LC_URL:          sw00362818000msb.lc
  SUN_POSTN:       174.08d {+11h 36m 20s}   +2.56d {+02d 33' 28"}
  SUN_DIST:         51.08 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
  MOON_POSTN:      141.58d {+09h 26m 19s}  +13.05d {+13d 02' 43"}
  MOON_DIST:        18.98 [deg]
  MOON_ILLUM:      8 [%]
  GAL_COORDS:      197.70, 31.42 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      122.65,  6.54 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        SWIFT-BAT GRB Lightcurve.  
  COMMENTS:           
  COMMENTS:        The next comments were copied from the BAT_POS Notice:  
  COMMENTS:        This is a rate trigger.  
  COMMENTS:        A point_source was found.  
  COMMENTS:        This does not match any source in the on-board catalog.  
  COMMENTS:        This does not match any source in the ground catalog.  
  COMMENTS:        This is a GRB.  
  COMMENTS:        This trigger occurred at longitude,latitude = 11.84,1.15 [deg].  
  

  
• GCN Circular #9913
  E. Troja (NASA/GSFC/ORAU), A. P. Beardmore (U Leicester), E. A. Hoversten (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (CRESST/GSFC/UMD), P. T. O'Brien (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), A. Rowlinson (U Leicester) and M. H. Siegel (PSU) report on behalf of the Swift Team:
  At 07:00:44 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090916 (trigger=362818). Swift did not slew to the GRB due to a Moon constraint. The BAT on-board calculated location is RA, Dec 126.579, +25.933 which is

     RA(J2000) = 08h 26m 19s
     Dec(J2000) = +25d 55' 60"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single short spike structure with a duration of about ~0.4 sec, followed by ~8 seconds of low-energy emission. The peak count rate was ~2500 counts/sec (15-350 keV), at ~0 sec after the trigger.
  Due to an observing constraint, Swift cannot immediately slew to the BAT position. There will thus be no XRT or UVOT data for this trigger until later today.
  Burst Advocate for this burst is E. Troja (eleonora.troja AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
• GCN Circular #9915
  S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), E. Troja (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team):
  Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of the short BAT GRB 090916 (trigger #362818) (Troja, et al., GCN Circ. 9913). The BAT ground-calculated position is RA, Dec = 126.582, 25.941 deg which is

    RA(J2000)  =  08h 26m 19.6s
    Dec(J2000) = +25d 56' 27.3"
  

  with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 34%.
  The mask-weighted light curve consisted of a single peak of 0.32 sec duration starting at T-0.128 sec, followed by low-level emission extending out to about T+70 sec. T90 (15-350 keV) is 63.4 +- 15.2 sec (estimated error including systematics).
  The time-averaged spectrum from T-0.0 to T+68.5 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.42 +- 0.33. The total fluence in the 15-150 keV band is 9.5 +- 1.8 x 10-7 erg/cm2. The peak second starting from T-0.036 sec is best fit by a simple power-law model. The power law index of the peak-second spectrum is 1.41 +- 0.28. The 1-sec peak fluence in the 15-150 keV band is 1.5 +- 0.26 x 10-7 erg/cm2. The 1-sec peak photon flux in the 15-150 keV band is 1.9 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
  The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/362818/BA/
• GCN Circular #9921
  J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander report:
  Skynet observed the Swift/BAT localization of short-duration GRB 090916 (Troja et al., GCN 9913) with four of the 16" PROMPT telescopes at CTIO beginning 2.6 hours after the trigger in UVRI through high airmass.
  We do not detect any uncatalogued sources. Stacking only images that increase the limiting magnitude yields:

  mean                                                    1-sig.   1-sig.
  time                               3-sig.               sys.     stat.
  since                              lim.     cal.        cal.     cal.
  trig.   tel.       exp.     fil.   mag.     stars*      unc.     unc.
  (h)                (# x s)                              (mag)    (mag)
  
  2.7     PROMPT-3   6 x 80   U      17.7     14 SDSS 7   1.137    0.011
  2.7     PROMPT-2   6 x 80   V      18.8     88 SDSS 7   0.020    0.001
  2.7     PROMPT-5   6 x 80   I      18.6     56 SDSS 7   0.073    0.000
  2.7     PROMPT-4   6 x 80   R      19.4     44 SDSS 7   0.005    0.000
  

  * Transformed using Jester et al., 2005, ApJ, 130, 873.
• GCN Circular #9925
  A. P. Beardmore, K. L. Page (U. Leicester) and E. Troja (NASA/GSFC/ORAU) report on behalf of the Swift-XRT team :
  Due to a Moon constraint, the Swift-XRT could not observe the field of the BAT short GRB 090916 (Troja et al., GCN Circ. 9913) until 9.3 hours after the trigger. In 12.3 ks of Photon Counting mode data (from 33.5 to 126.6 ks after the trigger) we do not detect any source within the BAT refined error circle of Barthelmy et al. (GCN Circ. 9915). The 3 sigma upper limit 0.3-10 keV count rate is 8 x 10^-4 count s^-1, which corresponds to an observed flux limit of 3 x 10^-14 erg cm^-2 s^-1 (assuming a typical count-to-observed flux conversion factor of 3.8 x 10^-11 erg cm^-2 ct^-1, Evans et al., 2009, MNRAS, 397, 1177).
  This circular is an official product of the Swift-XRT team.
• GCN Report 248.1
  GCN_Report 248.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_248_1.pdf by E. Troja at NASA/GSFC/ORAU titled: "Final Results on Swift GRB 090916"