GRB 140903A
GCN Circular 16815
Subject
Possible radio detection of GRB 140903A with the GMRT
Date
2014-09-12T08:44:42Z (12 years ago)
From
Poonam Chandra at TIFR <poonam@ncra.tifr.res.in>
A. J. Nayana (NCRA-TIFR) and Poonam Chandra (NCRA-TIFR) report:
We carried out the Giant Metrewave Radio Telescope (GMRT) observations of
GRB 1400903A (Cummings et al. GCN 16763) in the 1390 MHz band on 2014
September 11.05 UT. We detect a 3.1-sigma source at the GRB position
(Cenko et al.
16770) with a flux density of 102+/-33 uJy. This is most likely the
radio afterglow of
GRB 140903A. We are carrying out further observations to confirm this
detection.
We thank GMRT staff for making these observations possible.
GCN Circular 16813
Subject
GRB 140903A: Chandra detection of the afterglow
Date
2014-09-10T21:26:39Z (12 years ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
T. Sakamoto (AGU), E. Troja (GSFC/UMCP), N. Gehrels (GSFC),
J. Norris (BSU), S. D. Barthelmy (GSFC), J. L. Racusin (GSFC),
N. Kawai (Tokyo Tech), A. Fruchter (STScI)
A Chandra ToO observation of a short GRB 140903A (Cummings et al., GCN Circ. 16763;
Cummings et al., GCN Circ. 16765) started on September 6 08:54 UT (~2.7 days after the
GRB trigger) for a total of 19.8 ksec. The X-ray afterglow was clearly detected at
a position (RA, Dec) = (238.013519, +27.60303) which is equivalent to:
RA (J2000) = 15 52 03.24
Dec (J2000) = +27 36 10.9
The 1-sigma statistical error is 0.05 and 0.04 arcsec on RA and Dec respectively.
The systematic error of the Chandra aspect solution is 0.3 arcsec (radius, 68%
containment; i.e, http://cxc.harvard.edu/cal/ASPECT/celmon/) which dominates
the localization uncertainty.
The Chandra location is consistent with the enhanced XRT position (De Pasquale et al.,
GCN Circ. 16767) and the reported NIR, optical and radio afterglow/host candidate
(Capone et al., GCN Circ. 16769; Cenko et al., GCN Circ. 16785; Cenko et al.,
GCN Circ. 16770; Fruchter et al., GCN Circ. 16776; Fong, GCN Circ. 16777;
Dichiara et al., GCN Circ. 16781; Xu et al. GCN Circ. 16783; Levan et al. GCN Circ. 16784).
Our Chandra detection confirms the association of the reported NIR, optical and radio
candidate to GRB 140903A. Further Chandra observations are planned.
We would like to thank the Chandra operation team for rapidly approving and making
this observation.
GCN Circular 16785
Subject
GRB 140903A: Confirmation of Optical Fading from Discovery Channel Telescope
Date
2014-09-06T05:06:52Z (12 years ago)
From
S. Bradley Cenko at NASA/GSFC <brad.cenko@nasa.gov>
S. B. Cenko (NASA-GSFC), J. Capone, V. Toy (UMD), A. Cucchiara, E. Troja, A. Kutyrev (NASA-GSFC), S. Veilleux, and S. Gezari (UMD) report on behalf of a larger collaboration:
We obtained additional r'-band imaging of the candidate optical afterglow (Capone et al., GCN 16769) of the Swift short burst GRB 140903A (Cummings et al., GCN 16763) with the Discovery Channel Telescope, beginning at 2:55 UT on 6 September 2014 (2.5 d after the Swift trigger). Performing digital image subtraction using our most recent epoch as a template, we detect significant fading in this source, confirming the results of Levan et al. (GCN 16784). Assuming no afterglow contamination in our latest epoch, we measure an afterglow brightness of r' = 21.7 at the time of our first DCT images (~ 12 hr after the Swift trigger). This suggests the early emission was heavily contaminated by the host galaxy, consistent with the results of Fruchter et al. (GCN 16776) and Xu et al. (16783). A figure showing our subtraction image can be found at:
http://asd.gsfc.nasa.gov/Brad.Cenko/grb140903A_dct.pdf
The detection of optical variability, together with a coincident radio detection (Fong, GCN 16777), confirm the host association of z = 0.351 for GRB 140903A (Cucchiara et al., 16774). We encourage additional follow-up (e.g., super/kilonova searches) to help clarify the nature of the progenitor system of this event.
GCN Circular 16784
Subject
GRB 140903A: Possible optical variability
Date
2014-09-05T14:49:26Z (12 years ago)
From
Andrew Levan at U.of Leicester <A.J.Levan@warwick.ac.uk>
A.J. Levan (U. Warwick), S.B. Cenko, A. Cucchiara (NASA-GSFC), D.A. Perley (Caltech) report for a larger collaboration:
"We observed the location of the short GRB 140903A (Cummings et al. GCN 16763