Gamma-ray Burst 110107A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN NOTICE
  

  TITLE:           GCN/FERMI NOTICE
  NOTICE_DATE:     Fri 07 Jan 11 21:16:08 UT
  NOTICE_TYPE:     Fermi-GBM Flight Position
  RECORD_NUM:      46
  TRIGGER_NUM:     316127753
  GRB_RA:          271.383d {+18h 05m 32s} (J2000),
                   271.431d {+18h 05m 43s} (current),
                   271.168d {+18h 04m 40s} (1950)
  GRB_DEC:         +56.800d {+56d 47' 60"} (J2000),
                   +56.802d {+56d 48' 05"} (current),
                   +56.794d {+56d 47' 38"} (1950)
  GRB_ERROR:       22.30 [deg radius, statistical plus systematic]
  GRB_INTEN:       117 [cnts/sec]
  DATA_SIGNIF:     5.60 [sigma]
  INTEG_TIME:      1.024 [sec]
  GRB_DATE:        15568 TJD;     7 DOY;   11/01/07
  GRB_TIME:        76551.80 SOD {21:15:51.80} UT
  GRB_PHI:          12.00 [deg]
  GRB_THETA:        25.00 [deg]
  DATA_TIME_SCALE: 1.0240 [sec]
  HARD_RATIO:      0.92
  LOC_ALGORITHM:   3 (version number of)
  MOST_LIKELY:      95%  GRB
  2nd_MOST_LIKELY:   2%  Cyg X-1
  DETECTORS:       0,1,0, 1,0,0, 0,0,0, 0,0,0, 0,0,
  SUN_POSTN:       288.67d {+19h 14m 40s}  -22.33d {-22d 19' 41"}
  SUN_DIST:         80.45 [deg]   Sun_angle= 1.1 [hr] (West of Sun)
  MOON_POSTN:      327.86d {+21h 51m 27s}   -8.39d {-08d 23' 16"}
  MOON_DIST:        79.78 [deg]
  MOON_ILLUM:      12 [%]
  GAL_COORDS:       85.26, 28.59 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      274.46, 80.22 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
  COMMENTS:        This trigger occurred at longitude,latitude = 141.43,25.07 [deg].  
  

• GCN NOTICE
  

  TITLE:           GCN/FERMI NOTICE
  NOTICE_DATE:     Fri 07 Jan 11 21:16:27 UT
  NOTICE_TYPE:     Fermi-GBM Ground Position
  RECORD_NUM:      57
  TRIGGER_NUM:     316127753
  GRB_RA:          260.240d {+17h 20m 58s} (J2000),
                   260.284d {+17h 21m 08s} (current),
                   260.042d {+17h 20m 10s} (1950)
  GRB_DEC:         +58.210d {+58d 12' 36"} (J2000),
                   +58.200d {+58d 11' 59"} (current),
                   +58.258d {+58d 15' 28"} (1950)
  GRB_ERROR:       10.88 [deg radius, statistical only]
  DATA_SIGNIF:     6.20 [sigma]
  DATA_INTERVAL:   1.024 [sec]
  GRB_DATE:        15568 TJD;     7 DOY;   11/01/07
  GRB_TIME:        76551.80 SOD {21:15:51.80} UT
  GRB_PHI:           0.00 [deg]
  GRB_THETA:        21.00 [deg]
  E_RANGE:         44.032 - 279.965 [keV]
  LOC_ALGORITHM:   413 (Gnd S/W Version number)
  SUN_POSTN:       288.67d {+19h 14m 40s}  -22.33d {-22d 19' 41"}
  SUN_DIST:         83.92 [deg]   Sun_angle= 1.9 [hr] (West of Sun)
  MOON_POSTN:      327.87d {+21h 51m 28s}   -8.39d {-08d 23' 13"}
  MOON_DIST:        85.71 [deg]
  MOON_ILLUM:      12 [%]
  GAL_COORDS:       86.72, 34.60 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      237.14, 80.53 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
  COMMENTS:        This Notice was ground-generated -- not flight-generated.  
  

• GCN Circular #11545
  J. R. Cummings (GSFC/UMBC) on behalf of the Swift-BAT team
  GRB 110107A occurred at 21:15:51 UTC. It was observed by Fermi GBM (trigger 316127753) and occurred during a Swift slew with BAT event capture. There is a strong source in a mosaic of BAT images at RA, Dec 299.890, 41.889, which is

  RA (J2000)    19h 59m 33.6s
  Dec (J2000)   +41d 53m 19s
  

  with an estimated 90% uncertainty of 3 arcmin radius.
  The burst was about 100 seconds long, starting at about T-70 sec and lasting until about T+40 sec. The BAT event data ended at about T+21 sec. The burst had multiple peaks, with the largest flux at about T0, the time of the Fermi GBM trigger. The peak count rate in BAT was about 4000 counts/sec.
  A Swift Target of Opportunity observation has been requested and approved.
• GCN Circular #11546
  J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC) on behalf of the Swift-BAT team:
  Using the data set from T-70 to T+22 sec from recent telemetry downlinks, we report further analysis of BAT GRB 110107A (a ground-found burst) (Cummings, GCN Circ. 11545).
  The mask-weighted light curve shows low level multiple overlapping peaks starting at ~T-70 sec and ending at ~T+22 sec. The event-by-event data captured during the slew stops at T+22 sec. Using the on-board raw rates, there is a weak indication that the burst continued out to ~T+45 sec.
  The time-averaged spectrum from T-70 to T+22 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.58 +- 0.03. The fluence in the 15-150 keV band is at least 5.8 +- 0.5 x 10^-6 erg/cm2. All the quoted errors are at the 90% confidence level.
• GCN Circular #11547
  G. Stratta (ASDC), V. D'Elia (ASDC), P.A. Evans and M.R. Goad (U. Leicest= er) report on behalf of the Swift-XRT team:
  Swift began a target of opportunity observation of GRB 110107A on January 8, 2011 at 15:07 UT, approximately 17.8 hours after the burst detected by Fermi. The GRB was deteced during a Swift slew with BAT event capture. Swift data for these observations utilize Target ID 20157.
  The XRT began observing the field at 15:12:43 UT, 64.8 ks after the Fermi trigger.
  Using 2517 s of XRT Photon Counting mode data and 1 UVOT images, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec =3D 299.90910, 41.91400 which is equivalent to:

  RA (J2000): =A019 59 38.20
  Dec (J2000): +41 54 50.3
  

  with an uncertainty of 3.6 arcsec (radius, 90% confidence). This position is 1.7 arcminutes distant from the BAT position.
  This position may be improved as more data are received. =A0The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
  The count rate level is (1.2+/-0.2)10^-2 counts/s. We cannot state if the source is fading at this stage and we need to wait for more data.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #11551
  S. Immler (CRESST/UMCP/GSFC) and G. Stratta (ASDC) report on behalf of the Swift/UVOT team:
  Swift UVOT started observing the field of GRB 110107A on January 8, 2011 at 15:12 UT, approximately T+17.9 hours (Cummings, GCN Circ 11545).
  No optical afterglow consistent with the XRT position (Stratta et al., GCN Circ. 11547) is detected in individual or merged UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) are:

  Filter      T_start   T_stop    Exp(s)      Mag
  -----------------------------------------------
  v            64,646   75,090      2247 >20.5
  u            64,609   74,538      1638 >21.2
  -----------------------------------------------
  

  The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E_{B-V} = 0.459 mag (Schlegel et al., 1998, ApJS, 500, 525).
• GCN Circular #11565
  G. Stratta (ASDC) reports on behalf of the Swift-XRT team:
  Swift performed a second target of opportunity observation of GRB 110107A on January 12, 2011.
  The XRT began observing the field at 2011-01-12 18:07:47 UT, that is T+420.7 ks (4.87 days) (Cummings, GCN Circ. 11545). Using 2.1 ks of Photon Counting mode data we find that the source has faded down to a 3-sigma upper limit of 0.007 counts/s. Assuming a power law decay starting from the first source detection (Stratta et al., GCN Circ. 11547), the upper limit is consistent with a decay index steeper than alpha = -0.4.
  The fading nature of the source confirms its afterglow origin.
  This circular is an official product of the Swift-XRT team.
• GCN Report 317.1
  GCN_Report 317.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_317_1.pdf by G. Stratta at ASDC titled: "Final report on Swift Observations of GRB 110107A"