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, 16765) with Gemini-N beginning at 5 Sep 2014, 05:16 UT. At this epoch we obtained observations in iJ and K utilising GMOS-N and NIRI. The source reported by Capone et al. (GCN 16769) and Cenko et al. (GCN 1677) is well detected in all bands.
A comparison between these images and the acquisition images taken on 4 Sept 2014 (Cucchiaria et al. GCN 16774) is indicative of a fading by 0.12 +/- 0.04 mag. An image subtraction shows a residual consistent with this fading, although both photometry and image subtraction are complicated by the presence of the nearby bright star.
This decay is very slow in comparison to most GRB afterglows and implies a significant contribution from the underlying host galaxy, consistent with its pre-trigger detection (Fruchter GCN 16776, Xu et al. GCN 16783). We note that the source remains largely point like in our observation, and the centroid of the subtraction residual is offset only ~0.1" from the centre of the combined host+afterglow source."
GCN Circular 16783
Subject
GRB 140903A: NOT optical and NIR observations
Date
2014-09-05T14:11:50Z (12 years ago)
From
Dong Xu at DARK/NBI <dong.dark@gmail.com>
D. Xu (DARK/NBI), S. Geier (ESO), D. Malesani, J. P. U. Fynbo
(DARK/NBI), J. Harmanen (NOT), A. J. Levan (U. Warwick), P. Jakobsson
(U. Iceland) report on behalf of a large collaboration:
We observed the field of the short GRB 140903A (Cummings et al., GCN
16763) using the 2.5m Nordic Optical Telescope (NOT) equipped with
StanCam and NOTCam. We observed for a total of 20 and 30 min in the R-
and H- bands, respectively. The middle times of the observations are
29.898 hr and 30.315 hr after the BAT trigger, respectively.
The previously reported object (Capone et al., GCN 16769; Cenko et
al., GCN 16770; Fruchter, GCN 16776; Dichiara et al., GCN 16781) is
clearly detected in our R- and H-band stacked images. We found
R=20.1+/-0.5 mag calibrated with nearby SDSS stars and H=16.1+/-0.3
mag calibrated with the nearby 2MASS stars.
Note that a fuzzy source is present at the same position in the SDSS
field, especially in z-band. Together with the pre- and post-burst
observations, the optical brightness of the object either varies
slowly or remains constant (see also Fruchter, GCN 16776), which
implies that what we're observing in optical is basically the host
galaxy of the burst.
[GCN OPS NOTE(05sep14): Per author's request, the affilliation of SG
was changed to ESO.]
GCN Circular 16781
Subject
GRB 140903A: FTN observations
Date
2014-09-05T10:23:04Z (12 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
S. Dichiara, C. Guidorzi (U. Ferrara), J. Japelj (U. Ljubljana)
on behalf of a large collaboration report:
The 2-m telescope Faulkes Telescope North in Hawaii began observing
Swift GRB 140903A (Cummings et al. GCN Circ 16763) on September 04
at 06:35:20 UT, i.e. ~15.6 hours after the BAT trigger, with
the r' and i' filters.
We detect the optical source reported by Capone et al. (GCN 16769),
Cenko et al. (GCN 16770), Fruchter (GCN 16776) within an estimated
magnitude of r'=20.4 +- 0.5.
Given the measured values and relatively large uncertainties,
nothing can be inferred on the possible fading.
GCN Circular 16779
Subject
GRB 140903A: ISON-Kislovodsk observations
Date
2014-09-05T04:11:18Z (12 years ago)
From
Alexei Pozanenko at IKI <alex@grb.rssi.ru>
A. Pozanenko (IKI), A. Volnova (IKI), N. Polyakov (ISON), E. Romas (ISON), I. Molotov (KIAM), report on behalf of larger collaboration:
We observed the field of GRB 140903A (Cummings et al., GCN 16763) with Santel-400AN telescope of ISON-Kislovodsk observatory starting on Sep. 03 (UT) 18:54:36. In the enhanced XRT position (De Pasquale et al., GCN 16767) we do not detect the object (Capone et al., GCN 16769