Gamma-ray Burst 150110C

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #17293
  S. Nakahira (JAXA), H. Negoro (Nihon U.), S. Ueno, H. Tomida, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Serino, M. Morii, J. Sugimoto, T. Takagi, A. Yoshikawa, M. Matsuoka (RIKEN), N. Kawai, Y. Tachibana, T. Yoshii (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, D. Uchida (Osaka U.), M. Nakajima, K. Fukushima, T. Onodera, K. Suzuki, M. Fujita, F. Honda, T. Namba (Nihon U.), Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, A. Kawagoe (Chuo U.), M. Yamauchi, Y. Morooka, D. Itoh (Miyazaki U.), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team:
  The MAXI/GSC nova alert system triggered a bright uncatalogued hard X-ray transient source at UT2015-01-10T23:41:01.
  Assuming that the source flux was constant over the transit, we obtain the source position at
  (R.A., Dec) = (68.576 deg, -16.869 deg) = (04 34 18, -16 52 08) (J2000)
  with a statistical 90% C.L. elliptical error region with long and short radii of 0.19 deg and 0.17 deg respectively. The roll angle of long axis from the north direction is 165.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 281 +- 32 mCrab (4-10keV, 1 sigma error). There was no significant excess flux in the previous transit at UT 22:08 with an upper limit of 20 mCrab.
• GCN Circular #17298
  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 MAXI GRB 150110C. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00037
  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 MAXI 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 #17301
  K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team:
  Swift-XRT has observed the error circle of the MAXI GRB 150110C in a series of observations tiled on the sky. The total exposure time is 3.8 ks spread over 4 fields; the maximum exposure within the sky observed was 2.4 ks. The observations started 54.2 ks after the MAXI trigger. Within these data we detect an uncatalogued X-ray source at RA, Dec = 68.48007, -16.96802 which is equivalent to:

    RA (J2000.0)  = 04h 33m 55.22s
    Dec (J2000.0) = -16d 58' 04.9"
  

  with an uncertainty of 7.0 arcsec (radius, 90% confidence). The source has a mean X-ray (0.3-10 keV) count rate of 4.0 (+/- 2.2) x 10^-3 count s^-1. The exposure at this location was 1.5 ks. At the present time we cannot be sure whether or not this source is the afterglow.
  The results of the automatic processing for this source are available at http://www.swift.ac.uk/xrt_products/TILED_GRB00037/index_1.php This circular is an official product of the Swift-XRT team.
• GCN Circular #17302
  Paul Kuin (MSSL/UCL) reports on behalf of the Swift/UVOT team:
  The Swift/UVOT began settled observations of the field of MAXI GRB 150110C 54ks after the trigger. No optical afterglow consistent with the XRT position (Page, GCN Circ. No. 17301) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:

  Filter         T_start(s)   T_stop(s)      Exp(s)         Mag
    
  u                54238        59786         1896         >20.9
  

  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).