Gamma-ray Burst 070714

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #6619
  D. Grupe (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), M. M. Chester (PSU) and N. Gehrels (NASA/GSFC) report on behalf of the Swift Team:
  At approximately 03:18 +/-5min UT BAT triggered on a possible GRB (trigger 284850). Swift automatically slewed to the location RA=43.94 Dec=+30.24 (J2000). The uncertainty is 6 arcmin. We are uncertain about both the time and the location at this time because the trigger occurred during a TDRSS outage, so most of the regular TDRSS Notices were lost. We are also in the middle of the computer downtime as announced earlier today, so analysis of the full Malindi downlink data will have to wait until late Saturday UT.
  We wish to thank J. Knavel of the Swift Operations Team for notifying the science team that Swift had slewed to a GRB.
  Burst Advocate for this burst is D. Grupe (grupe AT astro.psu.edu). 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 #6622
  S.D. Barthelmy (GSFC), L. Barbier (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Grupe (PSU), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team):
  Using the data set from T-240 to T+962 sec from recent telemetry downlinks, we report further analysis of BAT GRB 070714A (trigger #284850) (Grupe, et al., GCN Circ. 6619). The BAT ground-calculated position is RA, Dec = 42.933, 30.241 deg which is

     RA(J2000)  =  2h 51m 43.8s
     Dec(J2000) = 30d 14' 28"
  

  with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 96%.
  The mask-weight lightcurve shows a single peak starting at T+0, peaking at T+0.7, and ending at T+2 sec, where the rise time is a little faster than the decay. T90 (15-350 keV) is 2.0 +- 0.3 sec (estimated error including systematics).
  The time-averaged spectrum from T-0.7 to T+2.3 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.6 +- 0.2. The fluence in the 15-150 keV band is 1.5 +- 0.2 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.30 sec in the 15-150 keV band is 1.8 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
  We note that the fluence ratio in a simple power-law fit between the 25-50 keV band and the 50-100 keV band is 1.52. This fluence ratio is larger than 1.32, which can be achieved in the Band function of alpha=-1.0, beta=-2.5, and Epeak=30 keV. Thus, preliminary analysis shows that Epeak of the burst is very likely around or below 30 keV. Therefore the burst can be classified as an X-ray flash.
• GCN Circular #6628
  D.Grupe (PSU) reports on behalf of the Swift/XRT team:
  I analyzed the first (and only) orbit of X-ray data of GRB 070714A (BAT trigger 284850; Grupe et al. GCN 6619) with a total exposure time of 2.3 ks. The XRT began observing the field of GRB 070714A at 2007-07-14 03:21:25 UT, 54.4 seconds after the BAT trigger. Using 799 s of overlapping XRT Photon Counting (PC) mode and UVOT V-band data, 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 = 42.93073, 30.24339 which is equivalent to:

  RA (J2000):  02 51 43.37
  Dec (J2000): +30 14 36.2
  

  with an uncertainty of 2.0" (90% confidence radius).
  The XRT PC mode light curve shows a fading afterglow with a decay slope of 1.02+\-0.29. The predicted count rate (flux) 24 hours after the burst is 1.5e-3 counts s-1 (1.4e-13 ergs s-1 cm-2) and 7.3e-4 counts s-1 (6.8e-14 ergs s-1 cm-2) at 48 hours after the trigger.
  The X-ray spectrum can be fitted by a single absorbed power law with the absorption column density in agreement with the Galactic value (NH=9.24e20 cm-2; Dickey & Lockman 1990) and a Photon spectra index Gamma = 1.68+\-0.23.
  This circular is an official product of the Swift XRT team.
• GCN Circular #6633
  M.M. Chester (PSU) and D. Grupe (PSU) report on the behalf of the Swift UVOT team:
  The Swift/UVOT observed the field of GRB070714A (trigger=284850) starting 2007-195-03:21:15, 44 s after the BAT trigger (Grupe et al. 2007, GCN Circ. 6619). We do not find any new source in any of the UVOT observations inside the refined XRT error circle (Grupe 2007, GCN Circ. 6628).
  The 3-sigma upper limits for detecting a source inside the XRT error circle in the first finding chart (FC) exposure and the co-added frames (including the finding chart) are:

  Filter   Tstart   Tstop    Exp     Magnitude
              (s)     (s)     (s)    (3-sigma UL)
  White FC    61     161      98.2     20.19
  White       61    1641     235       20.63
  v           44    1690     855       19.69
  b          647    5955     138       19.55
  u          622    5868     274       19.71
  uvw1       598    5664     274       19.03
  uvm2      5258    5458     197       18.96
  uvw2       677    1666      77.8     18.49
  

  The values quoted above are not corrected for the expected Galactic extinction corresponding to a reddening of E_{B-V} = 0.186 mag in the direction of the burst (Schlegel et al. 1998).
• GCN Circular #6636
  S.D. Barthelmy (GSFC) on behalf of the Swift-BAT team:
  It has been noted by several people (D. Grupe, M. Chester, and F. Marshall) that the T_zero trigger time for GRB 070714A (Grupe, et al., 6619; Barthelmy et al., 6622) is missing from the standard set of communications on this burst. Normally T_zero is published in the Notices and the "first Swift Circular" on the burst. But because all the TDRSS messages were lost due to a TDRSS outage, we dropped the ball on this in the later circular.
  The trigger time for GRB 070714A (trigger 284850) is 03:20:30.618 UT.
• GCN Report 71.1
  GCN_Report 71.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_71_1.pdf by D. Grupe at PSU titled: "Swift observations of GRB 070714A"
• D. Perley's Keck GRB Host project: suggests potential host galaxy at z=1.58 (OII). The nearby galaxy is at z=0.55.