Gamma-ray Burst 081016

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:          GCN/INTEGRAL NOTICE
  NOTICE_DATE:    Thu 16 Oct 08 06:52:15 UT
  NOTICE_TYPE:    INTEGRAL Wakeup
  TRIGGER_NUM:    5367,   Sub_Num: 0
  GRB_RA:         255.5686d {+17h 02m 16s} (J2000),
                  255.7017d {+17h 02m 48s} (current),
                  254.8122d {+16h 59m 15s} (1950)
  GRB_DEC:        -23.3375d {-23d 20' 14"} (J2000),
                  -23.3496d {-23d 20' 58"} (current),
                  -23.2663d {-23d 15' 58"} (1950)
  GRB_ERROR:      2.67 [arcmin, radius, statistical only]
  GRB_INTEN:      18.15 [sigma]
  GRB_TIME:       24722.47 SOD {06:52:02.47} UT
  GRB_DATE:       14755 TJD;   290 DOY;   08/10/16
  SC_RA:          260.49 [deg] (J2000)
  SC_DEC:         -25.64 [deg] (J2000)
  SUN_POSTN:      201.55d {+13h 26m 11s}   -9.05d {-09d 02' 42"}
  SUN_DIST:        53.61 [deg]   Sun_angle= -3.6 [hr] (East of Sun)
  MOON_POSTN:      38.77d {+02h 35m 05s}  +20.45d {+20d 26' 54"}
  MOON_DIST:      145.70 [deg]
  GAL_COORDS:     359.22, 11.19 [deg] galactic lon,lat of the burst
  ECL_COORDS:     256.77, -0.56 [deg] ecliptic lon,lat of the burst
  COMMENTS:       INTEGRAL GRB Coordinates.  
  COMMENTS:       Possibly real GRB event  
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:          GCN/INTEGRAL NOTICE
  NOTICE_DATE:    Thu 16 Oct 08 06:55:14 UT
  NOTICE_TYPE:    INTEGRAL Refined
  TRIGGER_NUM:    5367,   Sub_Num: 1
  GRB_RA:         255.5689d {+17h 02m 17s} (J2000),
                  255.7020d {+17h 02m 48s} (current),
                  254.8125d {+16h 59m 15s} (1950)
  GRB_DEC:        -23.3286d {-23d 19' 42"} (J2000),
                  -23.3407d {-23d 20' 26"} (current),
                  -23.2574d {-23d 15' 26"} (1950)
  GRB_ERROR:      2.57 [arcmin, radius, statistical only]
  GRB_INTEN:      27.94 [sigma]
  GRB_TIME:       24719.22 SOD {06:51:59.22} UT
  GRB_DATE:       14755 TJD;   290 DOY;   08/10/16
  SC_RA:          260.49 [deg] (J2000)
  SC_DEC:         -25.64 [deg] (J2000)
  SUN_POSTN:      201.55d {+13h 26m 11s}   -9.05d {-09d 02' 45"}
  SUN_DIST:        53.61 [deg]   Sun_angle= -3.6 [hr] (East of Sun)
  MOON_POSTN:      38.80d {+02h 35m 12s}  +20.46d {+20d 27' 29"}
  MOON_DIST:      145.73 [deg]
  GAL_COORDS:     359.22, 11.19 [deg] galactic lon,lat of the burst
  ECL_COORDS:     256.77, -0.55 [deg] ecliptic lon,lat of the burst
  COMMENTS:       INTEGRAL GRB Coordinates.  
  COMMENTS:       Possibly real GRB event  
  

• GCN NOTICE
  

  TITLE:          GCN/INTEGRAL NOTICE
  NOTICE_DATE:    Thu 16 Oct 08 08:13:12 UT
  NOTICE_TYPE:    INTEGRAL Offline
  TRIGGER_NUM:    5367,   Sub_Num: 2
  GRB_RA:         255.5724d {+17h 02m 17s} (J2000),
                  255.7055d {+17h 02m 49s} (current),
                  254.8160d {+16h 59m 16s} (1950)
  GRB_DEC:        -23.3301d {-23d 19' 47"} (J2000),
                  -23.3422d {-23d 20' 31"} (current),
                  -23.2589d {-23d 15' 31"} (1950)
  GRB_ERROR:      1.50 [arcmin, radius, statistical only]
  GRB_INTEN:      27.94 [sigma]
  GRB_TIME:       24719.22 SOD {06:51:59.22} UT
  GRB_DATE:       14755 TJD;   290 DOY;   08/10/16
  SC_RA:          260.49 [deg] (J2000)
  SC_DEC:         -25.64 [deg] (J2000)
  SUN_POSTN:      201.60d {+13h 26m 23s}   -9.07d {-09d 03' 57"}
  SUN_DIST:        53.56 [deg]   Sun_angle= -3.6 [hr] (East of Sun)
  MOON_POSTN:      39.60d {+02h 38m 25s}  +20.71d {+20d 42' 28"}
  MOON_DIST:      146.52 [deg]
  GAL_COORDS:     359.22, 11.19 [deg] galactic lon,lat of the burst
  ECL_COORDS:     256.77, -0.55 [deg] ecliptic lon,lat of the burst
  COMMENTS:       INTEGRAL GRB Coordinates.  
  COMMENTS:       refined_coordinates_after_offline_analysis  
  

• GCN Circular #8377
  D.Gotz (CEA-Saclay), S.Mereghetti, A.Paizis (IASF-Milano), S. Soldi, V.Beckmann, M. Beck, M. Tuerler (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:
  A GRB lasting about 34 s has been detected by IBAS in IBIS/ISGRI data at 06:51:31 UT of October 16.
  The coordinates (J2000) are:

  RA = 255.5725 [degrees]
  DEC= -23.3301 [degrees]
  

  with an uncertainty of 1.5 arcmin (90% c.l.).
  The burst is composed by two distinct peaks, and a preliminary spectral analysis gives a peak flux in the 20-200 keV range of about 2.4 ph/cmsq/s (1-s integration time) and a fluence over the same energy range of about 1.8x10e-6 erg/cmsq. Due to data gaps caused by telemetry saturation these values should be considered as lower limits.
  A plot of the light curve will be posted at
  http://ibas.iasf-milano.inaf.it/IBAS_Results.html
  This message can be cited.
• GCN Circular #8379
  P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT Team
  We have obtained 2 ks of XRT Photon Counting mode data of GRB 081016 (Gotz et al. GCN Circ. 8377), beginning 20.4 ks after the INTEGRAL trigger. We find an uncatalogued X-ray source at RA,Dec, 255.57032, -23.33556 which is equvialent to:

  RA (J2000.0):  17 02 16.88
  Dec (J2000.0): -23:20:08.0
  

  with an estimated uncertainty of 3.6" (radius, 90% confidence). This position is 21" from the INTEGRAL position, within the INTEGRAL error circle. It is not currently possible to determine whether this source is fading. Further observations are planned.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #8382
  B. E. Schaefer (Louisiana State), E.S. Rykoff (UCSB), and H. Swan (U. Mich.) report on behalf of the ROTSE collaboration:
  ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, responded to GRB 081016A (Swift trigger 331856), producing images beginning 6.4 s after the GCN notice time. An automated response took the first image at 19:47:59.4 UT, 44.9 s after the burst, under excellent conditions. We took 10 5-sec, 10 20-sec and 20 60-sec exposures. These unfiltered images are calibrated relative to USNO A2.0 (R). Imaging is on going.
  Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma Swift/BAT error circle or the XRT error circle, for both single images and coadding into sets of 10; the field is not crowded. Individual images have limiting magnitudes ranging from 15.8-17.1; we set the following specific limits.

  start UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?
  --------------------------------------------------------------------
  19:47:59.4   19:48:04.4         5     15.8           44.9       N
  19:47:59.4   19:49:15.5        76     17.5           44.9       Y
  

• GCN Circular #8396
  P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
  Swift-XRT reobserved the field of the INTEGRAL GRB 081016A (Gotz et al. GCN Circ. 8377) 5.2 days after the trigger, obtaining 3.8 ks of data in Photon Counting (PC) mode. The source seen in the earlier XRT observation (Evans, GCN Circ. 8379) was no longer detected. A three-sigma upper limit on the count rate is 4.7e-3 counts/sec, significantly below the level of the previous detection (0.03 counts/sec). We therefore confirm that this was the afterglow of GRB 081016A.
  A spectrum formed from the first XRT observation, totalling 2 ks in PC mode, can be modelled with an absorbed power law with photon index 2.60 (+0.94, -0.81). The absorption column is consistent with the Galactic value of 1.7e21 cm^-2 (Kalberla et al 2005). The counts to observed (unabsorbed) flux conversion factor is 1.1e-12 (3.0e-12) erg cm^-2 ct^-1.
  This circular is an official product of the Swift-XRT team.
• GCN Report 171.1
  GCN_Report 171.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_171_1.pdf by P.A. Evans at U. Leicester titled: "Final Swift report on INTEGRAL GRB 081016A"