Gamma-ray Burst 150710B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #18009
  J. R. Cummings (CPI), D. M. Palmer (LANL), V. Pal'shin(Ioffe), and D. Svinkin (Ioffe)
  At 08:05:35, the bright GRB 150710B was observed by Swift/BAT during a preplanned Swiftslew. It was also seen by KONUS/WIND, and the KW team notified the BAT team of the event. In a mosaic of BAT images from photon- eventdata recorded during the slew, a bright source was found at RA, Dec 83.195, -46.963,which is:

  RA (J2000)05h 32m 46.9s
  Dec (J2000) -46d 57' 47"
  

  with an estimated uncertainty of 2 arcmin 90% containment.
  The burst had an estimated T90 of about 16 seconds. There were multiple bright peaks and an exponential decay.
  A Swift TOO has been requested in order to locate the afterglow.
• GCN Circular #18010
  P. A. Evans (U. Leicester) reports on behalf of the Swift team:
  Swift has initiated a ToO observation of the Swift/BAT GRB 150710B. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/ToO_GRBs/00020542
  Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the Swift/BAT event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration.
  Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
  This circular is an official product of the Swift-XRT team.
• GCN Circular #18013
  J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
  Using the data set from T-47 to T+50 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150710B. (Cummings, et al., GCN Circ. 18009). The refined BAT position is RA, Dec = 83.191, -46.960 deg, which is

      RA(J2000)  =  05h 32m 45.8s
      Dec(J2000) = -46d 57' 34"
  

  with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%.
  The mask-weighted light curve shows 6 overlapping but well-defined peaks followed by an exponential decay to background. T90 (15-350 keV) is 15 +- 1 sec (estimated error including systematics).
  The time-averaged spectrum from T+0 to T+15 sec is best fit by a model of a power law with an exponential cutoff. The photon index of the time-averaged spectrum is 0.99 +- 0.09. Epeak was 166 +- 28 keV. Using this model, the fluence in the 15-150 keV band was (3.5 +- 0.1) x 10^-6 ergs/cm^2. A simple power-law fit has a photon index of 1.34 +- 0.02.
  The 1-sec peak photon flux measured from T+3.5 sec in the 15-150 keV band was 8.3 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
  A Swift TOO is being executed (Evans, GCN #18010).
  Because this was a ground-detected burst, the usual automated BAT data products are not available.
• GCN Circular #18018
  A. Melandri (INAF-OAB), P. Kuin (MSSL-UCL), V. D'Elia (ASDC), A. D'ai (INAF-IASFPA), L.M. McCauley (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), K.L. Page (U. Leicester), C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester), A. Maselli (INAF-IASFPA) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
  Swift-XRT has performed follow-up observations of the Swift/BAT-detected burst GRB 150710B (Cummings et al. GCN Circ. 18009), collecting 2.8 ks of Photon Counting (PC) mode data between T0+115.2 ks and T0+121.6 ks.
  An uncatalogued X-ray source has been detected close to the refined Swift/BAT error region (Cummings et al. GCN Circ. 18013), it is below the RASS limit and shows no definitive signs of fading. Therefore, at the present time we cannot confirm this as the afterglow. Details of this source are given below:

    RA (J2000.0):  83.2176  =  05:32:52.23
    Dec (J2000.0): -46.9423  =  -46:56:32.4
    Error: 4.7 arcsec (radius, 90% conf.)
    Count-rate: 0.0141 [+0.0031, -0.0027] ct s^-1
  

  The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at http://www.swift.ac.uk/ToO_GRBs/00020542.
  Simultaneous with the Swift-XRT, the Swift-UVOT observed the field of GRB 150710B. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:

  Filter	       T_start(s)   T_stop(s)	   Exp(s)	Mag
  
  white	       115375	    120586	   662	       >21.1
  v	       115594	    121561	   957	       >19.5
  u	       115157	    120072	   915	       >20.5
  

  The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.04 in the direction of the burst (Schlegel et al. 1998).
  This circular is an official product of the Swift-XRT team.
• GCN Circular #18019
  S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, and T. Cline on behalf of the Konus-Wind team, report:
  The long-duration GRB 150710B (Swift-BAT ground detection: Cummings et al., GCN 18009) triggered Konus-Wind at T0=29133.922 s UT (08:05:33.922).
  The KW light curve shows a multi-peaked emission complex with a total duration of ~8.5 s. The emission is visible up to ~5 MeV.
  The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB150710_T29133/
  As observed by Konus-Wind, the burst had a fluence of 1.1(-0.2,+0.2)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+4.032 s, of 6.8(-1.3,+1.2)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
  The time-averaged spectrum (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.81 (-0.23,+0.30), the high energy photon index beta = -2.27 (-0.33,+0.18), the peak energy Ep = 154 (-30,+37) keV, chi2 = 75/97 dof.
  All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
• GCN Circular #18022
  A. Melandri, P. D'Avanzo, M.G. Bernardini (INAF-OAB), K.L. Page, P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
  Swift-XRT has conducted further observations of the field of the Swift/BAT-detected burst GRB 150710B (Cummings et al. GCN Circ. 18009). The observations now extend from T0+115 ks to T0+259 ks.
  The source reported by Melandri et al. (GCN Circ. 18018) has significantly faded between two epochs, down to a level of (7 +/- 2)e-3 cts/s, and is therefore the GRB afterglow.
  The results of the full analysis of the XRT observations are available at http://www.swift.ac.uk/ToO_GRBs/00020542.
  This circular is an official product of the Swift-XRT team.