Gamma-ray Burst 140723A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #16623
  E. Bissaldi (University & INFN Trieste), R. Desiante (Udine University & INFN Trieste), M. Axelsson (Stockholm University), D. Kocevski (NASA/GSFC) and F. Piron (LUPM) report on behalf of the Fermi-LAT team:
  At UT 01:36:30.73 on July 23rd, 2014, Fermi-LAT detected high-energy emission from GRB 140723A, which was also detected by Fermi-GBM (trigger427772193 / 140723067).
  The best LAT on-ground location is found to be
  (RA, Dec) = 210.63, -3.73 (deg, J2000)
  with an approximate error radius of 0.35 deg (90% containment, statistical error only). This was 55 deg from the LAT boresight at the time of the trigger.
  An image with the 68% and 90% containment regions have been posted at:
  http://slac.stanford.edu/~bissaldi/GRB140723A_LAT_tsmap.png
  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 170 photons above 100 MeV and 3 photons above 1 GeV are observed within 1200 s, before the spacecraft entered the SAA. The source entered the FoV again around 5800 s after the trigger. The highest-energy photon is a 1.8 GeV event, which is observed 163 s after the GBM trigger.
  A Swift ToO has been requested for this burst.
  The Fermi-LAT point of contact for this burst is Elisabetta Bissaldi (Elisabetta.Bissaldi@ts.infn.it).
  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 #16624
  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 140723A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00027
  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 #16625
  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,
  A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, and
  V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa, and A. Goldstein, on behalf of the Fermi GBM team, report:
  The long-duration GRB 140723A (Bissaldi et al., GCN Circ. 16623) has been observed by Konus-Wind, Fermi(GBM trigger 427772193), MESSENGER (GRNS), and INTEGRAL (SPI-ACS), so far, at about 5791 s UT (01:36:31).
  We have triangulated it to a GBM-MESSENGER annulus centered at RA(2000)=284.016 deg (18h 56m 04s) Dec(2000)=-22.344 deg (-22d 20' 38"), whose radius is 72.790 + / - 0.166 deg (3 sigma).
  The LAT error circle (that is RA, Dec, RErr = 210.63, -3.73, 0.35), whose area is 0.4 sq. deg, is mainly outside the annulus. The distance between the annulus center line and the center of the LAT position is 0.43 deg.
  This localization may be improved.
  A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB140723_T05790/IPN/
  
• GCN Circular #16626
  E. Burns (UAH) reports on behalf of the Fermi GBM Team:
  "At 01:36:30.73 UT on 23 July 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 140723A (trigger 427772193 / 140723067). It was also detected by Fermi LAT (Bissaldi et al. 2014, GCN 16623). 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 56 s (50-300 keV). The time-averaged spectrum from T0+0.002 s to T0+56.801 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -1.1 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 968 +/- 231 keV.
  The event fluence (10-1000 keV) in this time interval is (1.46 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.000 s in the 10-1000 keV band is 4.8 +/- 0.2 ph/s/cm^2.
  The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
• GCN Circular #16627
  C. Guidorzi, S. Dichiara (U. Ferrara), C.G. Mundell (LJMU) on behalf of a large collaboration report:
  We observed Fermi GRB 140723A (Bissaldi et al. GCN Circ 16623; Burns et al. GCN Circ. 16626) with one of the Las Cumbres Observatory 1-m telescopes in Sutherland (South Africa) on July 23 at 16:51:02 UT, i.e. ~15.2 hours after the GBM trigger, with the r' and i' filters.
  From initial quick-look images, we identify an possible uncatalogued object within the LAT error circle at the following position:

  RA(J2000) = 14:02:30.25
  Dec(J2000)= -03:40:21.0
  

  with an uncertainty of 2" and R~17 mag, calibrated against nearby USNOB1 stars.
• GCN Circular #16628
  S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lyssenko, and T. Cline on behalf of the Konus-Wind team, report:
  The long-duration, hard-spectrum GRB 140723A (Fermi-LAT detection: Bissaldi et al., GCN 16623; IPN triangulation: Hurley et al., GCN 16625; Fermi-BBM detection: Burns, GCN 16626) triggered Konus-Wind at T0=5790.357 s UT (01:36:30.357).
  The light curve shows a single FRED-like pulse with a total duration of ~45 s. The emission is seen up to 10 MeV.
  As observed by Konus-Wind, the burst had a fluence of 2.3(-0.5,+0.8)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0-0.064 s, of 5.8(-1.6,+1.9)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
  The time-averaged spectrum (measured from T0 to T0+33.024 s) is best fit in the 20 keV - 15 MeV range by the cutoff power law with the following model parameters: the photon index alpha = -1.10(-0.20,+0.26), and the peak energy Ep = 1142(-452,+1005) keV, chi2 = 71/98 dof. Fitting this spectrum with the Band model yields the same values of alpha and Ep with an upper limit on beta of -1.9
  The spectrum near the peak count rate (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 15 MeV range by the cutoff power law with the following model parameters: the photon index alpha = -1.03(-0.21,+0.26), and the peak energy Ep = 931(-287,+528) keV, chi2 = 97/98 dof.
  The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB140723_T05790/
  All the quoted errors are at the 90% sigma confidence level. All the quoted values are preliminary.
• GCN Circular #16629
  E. Gorbovskoy, D.Denisenko, V. Lipunov, M.Pruzhinskaya, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, A.Sankovich Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University
  K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University
  V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk
  A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory
  V.Krushinsky, I.Zalozhnih, A. Popov Ural Federal University, Yekaterinburg, Kourovka
  Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
  Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA)
  MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka was pointed to the GRB 140723A (Fermi trigger 427772193) 48377 s (~13.4 h) after trigger time at 2014-07-23 15:02:47 UT directly after sunset. Observations were made at high zenith distance (z ~ 76d) with the error box setting to the horizon. Therefore we have only two (180s exposure) successful images.
  On our images we have not found optical transient within Fermi-LAT error-box (Bissaldi et al. GCN 16623, Burns et. al GCN 16626) and IPN (Hurley et al. GCN 16625, Golenetskii et. al GCN 16628) brighter than 18.3 mag. Thus we can not confirm the LCO-Sutherland OT (Guidorzi et al. GCN 16627) despite ~2 hours earlier time of observations and our upper limit being 1 magnitude deeper than the estimated object magnitude.
  The 6x6 acrminutes MASTER-Tunka image around probable OT position (Guidorzi et al. GCN 16627) is available here: http://master.sai.msu.ru/static/GRB/GRB140723_LAT.png
  Our white (clear) band is well described by a parity 0.8R+0.2B (USNO B1).
  The message may be cited.
  
• GCN Circular #16630
  C. Guidorzi, S. Dichiara (U. Ferrara), C.G. Mundell (LJMU) on behalf of a large collaboration report:
  From the analysis of the finally reduced frames we retract the uncatalogued source reported in our previous message (GCN Circ. 16627) as the possible optical afterglow candidate to GRB 140723A. The source turned out to be not real. We apologise for the confusion.
• GCN Circular #16631
  V. D'Elia (ASDC), L. Izzo (URoma/ICRA), A. Breeveld (UCL-MSSL), P. Evans (U. Leicester) report on behalf of the Swift team:
  Swift began observing the field of GRB 140723A on 2014-07-23 at 15:20 UT, 49 ks after the LAT trigger (Bissaldi et al., GCN Circ. 16623). A tiled observation of four contiguous fields centered on the LAT > coordinates has been secured. The total integration time is 3 ks, > i.e., about 750 s per field. Our mosaic covers more than 90% of the LAT error circle (Bissaldi et al., GCN Circ. 16623), but less than 10% of the observed area lies within the IPN error localization, published after our observation began (Hurley et al., GCN Circ. 16625).
  In the XRT exposure, we do not find any new source, down to a three sigma upper limit of 1.4E-02 cts/s. In the UVOT u-band data we do not find any new source down to a three sigma upper limit of about 20.2 mag.
  This circular is an official product of the Swift team.