Gamma-ray Burst 150530B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #17895
  J. R. Cummings (CPI) and D. M. Palmer (LANL) report on behalf of the Swift science team:
  At 13:28:38 during a preplanned Swift slew, GRB 150530B caused a rate increase in Swift-BAT. Photon event data were collected during the slew. In ground analysis, we detect a significant source in a mosaic image. The source was at RA, Dec 7.496, +44.290 which is:

  RA (J2000)   00h 29m 59.0s
  Dec (J2000) +44d 17' 25"
  

  with an estimated 90% containment radius of 3 arcmin.
  In BAT, the burst lasted 2.0 +- 0.4 seconds. The spectrum was soft, with no detected excess above 100 keV.
  The best fit to the spectrum from 15-150 keV is a simple power law with a photon index of 1.7 +- 0.2. The fluence in 2 seconds was (1.25 +- 0.2) x 10^-7 ergs/cm^2. The uncertainties quoted are estimated 90% confidence.
• GCN Circular #17896
  P. A. Evans (U. Leicester) reports on behalf of the Swift team:
  Swift has initiated a ToO observation of the Swift/BAT GRB 150530B. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/ToO_GRBs/00020522
  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 #17899
  P. D'Avanzo (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester), V. D'Elia (ASDC), A. D'a=EC (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 150530B (Cummings et al. GCN Circ. 17895), collecting 4.8 ks of Photon Counting (PC) mode data between T0+239.2 ks and T0+247.3 ks.=20
  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 ~0.003 to ~0.004 ct s^-1, corresponding to a 0.3-10 keV observed flux of 1.0e-13 to 1.5e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum).
  Four uncatalogued sources were detected too far from the GRB position to be likely afterglow candidates.
  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/00020522.
  This circular is an official product of the Swift-XRT team.