Gamma-ray Burst 140729A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #16633
  M. Arimoto (Tokyo Tech) and E. Bissaldi (University & INFN Trieste) report on behalf of the Fermi-LAT team:
  At UT 00:36:59 on July 29th, 2014, Fermi-LAT detected high-energy emission from GRB 140729A, which was also detected by Fermi-GBM (trigger 140729026 / 428287016).
  The best LAT on-ground location is found to be
  (RA, Dec) = 193.95, +15.35 (deg, J2000)
  with an approximate error radius of 0.34 deg (90% containment, statistical error only). This was 26.2 deg from the LAT boresight at the time of the trigger.
  The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the GBM emission with high significance. More than 100 photons above 100 MeV and 13 photons above 1 GeV are observed within 550 s, before the spacecraft entered the SAA. The GRB does not come back into the Fermi-LAT FoV for more than 6000s. The highest-energy photon is a 1.3 GeV event which is observed 44 s after the GBM trigger.
  A Swift ToO has been requested for this burst.
  The Fermi-LAT point of contact for this burst is Makoto Arimoto (arimoto@hp.phys.titech.ac.jp).
  The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.
• GCN Circular #16634
  P. A. Evans (U. Leicester) reports on behalf of the Swift team:
  Swift has initiated a series of observations, tiled on the sky, of the Fermi/LAT GRB 140729A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00028
  Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the Fermi/LAT event is high: 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; and 2009, MNRAS, 397, 1177).
  This circular is an official product of the Swift-XRT team.
• GCN Circular #16635
  E. Bissaldi (University & INFN Trieste) and M. Arimoto (Tokyo Tech) report on behalf of the Fermi-LAT team:
  The number of LAT-detected photons reported in GCN 16633 is incorrect. There are only about 20 photons above 100 MeV and 4 photons above 1 GeV within 550 s.
  We apologize for the mistake.
• GCN Circular #16636
  M. Stanbro (UAH) reports on behalf of the Fermi GBM Team:
  "At 00:36:53.71 UT on 29 July 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 140729A (trigger 428287016 / 140729026). It was also detected by Fermi LAT (Arimoto et al. 2014, GCN 16633). The GBM on-ground location is consistent with the LAT position.
  The GBM light curve consists of a single pulse with a duration (T90) of about 78 s (50-300 keV). The time-averaged spectrum from T0+0.0 s to T0+78.3 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -0.9 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 866 +/- 162 keV.
  The event fluence (10-1000 keV) in this time interval is (1.70 +/- 0.06)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+3.328 s in the 10-1000 keV band is 4.5 +/- 0.3 ph/s/cm^2.
  The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
• GCN Circular #16637
  K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,
  S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team,
  V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa, and A. Goldstein, on behalf of the Fermi GBM team,
  S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team, and
  A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, report:
  The long-duration GRB 140729A (Arimoto and Bissaldi, GCN Circ. 16633) has been observed by Konus-Wind, Fermi(GBM trigger 428287016), MESSENGER (GRNS), Swift (BAT), and INTEGRAL (SPI-ACS), so far, at about 2214 s UT (00:36:54). The burst was outside the coded field of view of the BAT.
  We have triangulated it to a GBM-MESSENGER annulus centered at RA(2000)=115.909 deg (07h 43m 38s) Dec(2000)=+22.015 deg (+22d 00' 52"), whose radius is 73.685 +/- 0.219 deg (3 sigma).
  This annulus intersects the Fermi-LAT 1 sigma error circle (GCN 16633) to form an error box whose area is about (654 sq. arcmin.) which is two times smaller than that of the LAT error circle.
  This localization may be improved.
  A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB140729A/IPN/
  Details of the Konus-Wind observation will be given in a forthcoming GCN Circular.
  
• GCN Circular #16638
  P. D'Avanzo (INAF-OAB), F. E. Marshall (NASA/GSFC), M. G. Bernardini (INAF-OAB), P. A. Evans (U. Leicester) report on behalf of the Swift team:
  Swift began observing the field of GRB 140729A (Arimoto et al., GCN Circ. 16633; Stanbro, GCN Circ. 16636) on 2014-07-29 at 10:12 UT, 34.5 ks after the LAT trigger (Arimoto et al., GCN Circ. 16633). A tiled observation of four contiguous fields centered on the LAT coordinates has been secured. The total integration time is 3.8 ks, i.e., about 1 ks per field. Our mosaic covers about 90% of the LAT error circle (Arimoto et al., GCN Circ. 16633) and about 50% of the observed area lies within the IPN error localization, published after our observation began (Hurley et al. GCN Circ 16637).
  In the XRT exposure, we do not find any new source, down to a three sigma upper limit of 9e-03 cts/s.
  UVOT observed the four fields using the U filter. No new source was found down to a 90%-confidence upper limit of about 20.0 mag. No correction is made for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998).
  This circular is an official product of the Swift team.
• GCN Circular #16640
  L. P. Singer (Caltech), S. B. Cenko (NASA/GSFC), and M. M. Kasliwal (Carnegie Observatories/Princeton) report on behalf of the intermediate Palomar Transient Factory (iPTF) collaboration:
  We searched for optical counterparts of GRB 140729A (Arimoto, GCN 16633; Bissaldi, GCN 16635; Stanbro, GCN 16636) using the Palomar 48-inch Oschin telescope (P48). Based on the final Fermi GBM localization with a 1-sigma statistical radius of 1.57 deg, we imaged 10 fields covering an area of 73 deg2. These fields also contained all of the Fermi LAT error circle and its intersection with the IPN annulus (Svinkin, GCN 16637).
  In our observations on 2014-07-29 from 04:05:50 to 04:51:48 UT (3.48 to 4.5 hours after the burst), we find no plausible optical afterglow candidates within the LAT error circle, to a limiting magnitude of R=20.6.
  The diagram http://www.its.caltech.edu/~lsinger/iptf/Fermi428287016.pdf shows the locations of our ten P48 fields in relation to the Fermi GBM 1- and 2-sigma statistical+systematic contours as well as the LAT error circle and the IPN annulus.
  
• GCN Circular #16648
  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, hard-spectrum GRB 140729A (Fermi-LAT detection: Arimoto and Bissaldi, GCN 16633; IPN triangulation: Hurley et al., GCN 16637) triggered Konus-Wind at T0=2213.751 s UT (00:36:53.751).
  The burst light curve shows a single pulse with a duration of ~16 s followed by a weak tail seen up to T0+33s. The emission is seen up to ~2 MeV.
  As observed by Konus-Wind, the burst had a fluence of 2.0(-0.2,+0.3)x10^-5 erg/cm2, and a 64-ms peak energy flux, measured from T0+2.656 s, of 4.5(-1.6,+1.7)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
  The time-integrated spectrum of the burst (measured from T0 to T0+16.640 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.65(-0.29,+0.36), and Ep = 592(-122,+187) keV (chi2 = 76/89 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.7 (chi2 = 76/88 dof).
  The spectrum near the peak count rate (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 2 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.68(-0.29,+0.35), and Ep = 619(-132,+233) keV (chi2 = 51/60 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.0 (chi2 = 51/59 dof).
  The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB140729_T02213/
  All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.