Gamma-ray Burst 150407A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #17681
  P. A. Evans (U. Leicester) reports on behalf of the Swift team:
  Swift has initiated a ToO observation of the Swift/BAT GRB 150407A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/ToO_GRBs/00020487
  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 #17682
  GRB 150407A: Swift detection of a possible burst
  D. M. Palmer (LANL) reports on behalf of the Swift Team:
  At 00:31:10, the Swift Burst Alert Telescope (BAT) detected a possible source, GRB 150407A (trigger=637342), with marginal statistical significance, in two consecutive images of 6 minutes total duration. The BAT on-board calculated location is RA, Dec 216.603, 38.541 (J2000), which is

    RA(J2000)  =  14h 26m 25s
    Dec(J2000) =  38d 32' 28"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is usual for image triggers, no obvious variation is visible in the BAT lightcurve.
  After ground discovery of this pair of possible detections, a ToO observation is planned to search for a counterpart afterglow. See GCN#17681 for details.
• GCN Circular #17683
  K. Wiersema (University of Leicester) reports on behalf of the Oadby Transients Team:
  We observed the field of possible GRB 150407A (Palmer et al. GCN 17682) using the 0.5m telescope of the observatory of the University of Leicester, at Oadby (UK). In a series of V band exposures, with midpoint 21.32 UT on 7 April 2015 (~0.88 days after burst, GCN 17682), we find no source brighter than the DSS limit, in or near the BAT error circle (GCN 17682).
• GCN Circular #17684
  J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), A. Amaral-Rogers (U. Leicester), J.P. Osborne (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D.N. Burrows (PSU) 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 150407A (Palmer et al. GCN Circ. 17682), collecting 2.0 ks of Photon Counting (PC) mode data between T0+68.5 ks and T0+70.5 ks.
  No X-ray sources have been detected inside or close to the Swift/BAT error region. The 3-sigma upper limit in the field ranges from ~0.004 to ~0.009 ct s^-1, corresponding to a 0.3-10 keV observed flux of 1.4e-13 to 3.8e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum).
  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/00020487.
  This circular is an official product of the Swift-XRT team.