GRB 210306A
GCN Circular 30080
Subject
GRB 210306A: LBT observations of the likely host galaxy
Date
2021-05-26T12:33:42Z (4 years ago)
From
Andrea Rossi at INAF <andrea.rossi@inaf.it>
A Rossi (INAF-OAS) and D. B. Malesani (DTU space) report on behalf of
the CIBO collaboration:
We observed the field of GRB 210306A (D'Elia et al., GCN 29597)
simultaneously in the r' and z' bands with the LBC imager mounted on LBT
(Mt Graham, AZ, USA). We obtained 20min of imaging on 2021-05-10, 65
days after the burst trigger and 60 days after our first observation
(Rossi et al., GCN 29645). Observations were performed under good
weather conditions with an average seeing of ~1.3".
At the location of the optical afterglow, we detected an object which is
likely the GRB host galaxy. We measure the following AB magnitudes:
r=24.6+-0.2
z=24.4+-0.4
calibrated against SDSS field stars.
We acknowledge the excellent support from the LBTO and LBT-INAF staff,
particularly A. Cardwell, S. Allanson, F. Cusano, S. Paiano and D.
Paris, in obtaining these observations.
GCN Circular 29657
Subject
GRB 210306A: GIT optical follow-up
Date
2021-03-15T11:34:37Z (5 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar(IITB), K. Sharma (IITB), J. Stanzin (IAO), A. Dutta(IIA), V.
Bhalerao(IITB), G. C. Anupama(IIA), S. Barway(IIA) report on behalf of the
GIT team:
We observed GRB 210306A detected by Swift Burst Alert Telescope (V. D'Elia
et. al., GCN 29597) and optical afterglow confirmed by (Alan M. Watson et.
al., GCN 29598), with the 0.7m GROWTH-India Telescope (GIT). We
obtained multiple
exposures in the r' filter. We clearly detected the afterglow in our stacked
image at R.A. = 08:39:49.99, DEC. = +60:12:19.09. The photometric results
follow as:
--------------------------------------------------------
JD (mid) | T_mid-T0(hrs) | Filter | Magnitude (AB) |
--------------------------------------------------------
2459280.20139 | 12.9 | r' | 20.87 +/0.05 |
--------------------------------------------------------
The magnitude is in agreement with that reported by Z.P. Zhu et al., (GCN
29607), around the same time of our observation. The magnitudes are
calibrated against PanSTARRS (Flewelling et al., 2018) and not corrected
for galactic extinction.
The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7 degree
field of view, set up by the Indian Institute of Astrophysics and the
Indian Institute of Technology Bombay with support from the Indo-US Science
and Technology Forum (IUSSTF) and the Science and Engineering Research
Board (SERB) of the Department of Science and Technology (DST), Government
of India (https://sites.google.com/view/growthindia/). It is located at the
Indian Astronomical Observatory (Hanle), operated by the Indian Institute
of Astrophysics (IIA).
GCN Circular 29654
Subject
GRB 210306A: HCT optical upper limit
Date
2021-03-13T04:44:34Z (5 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar (IITB), A. Dutta (IIA), R. Gupta (ARIES), V. Bhalerao (IITB), G.
C. Anupama (IIA), S. Barway (IIA), D.K. Sahu (IIA), A. Kumar (ARIES),
Dimple (ARIES), A. Ghosh (ARIES), S. B. Pandey (ARIES), and K. Misra
(ARIES) report:
We observed GRB 210306A detected by Swift Burst Alert Telescope (V. D'Elia
et. al., GCN 29597) and optical afterglow confirmed by Alan M. Watson et.
al., (GCN 29598) with the 2.0m Himalayan Chandra Telescope (HCT) of the
Indian Astronomical Observatory. We obtained 6 exposures of 300 sec each in
the Bessell R filter. We did not detect the afterglow in our stacked image.
The photometric upper limit is:
--------------------------------------------------------
JD (mid) | T_mid-T0(hrs) | Filter | Lim_mag (5-sigma) |
--------------------------------------------------------
2459282.110905 | 58.76 | Bessell R | > 23.22 |
--------------------------------------------------------
The magnitudes are in the AB system of magnitude calibrated against PanSTARRS
(Flewelling et al., 2018) using Lupton's transformation equations available
at http://classic.sdss.org/dr4/algorithms/sdssUBVRITransform.html#Lupton2005.
The magnitudes are not corrected for galactic extinction.
These observations were carried out under the ToO program HCT-2021-C1-P2.
We thank the HCT staff for their support during the observations. The
Indian Astronomical Observatory is operated by the Indian Institute of
Astrophysics, Bengaluru, India.
GCN Circular 29645
Subject
GRB 210306A: LBT observations
Date
2021-03-11T12:21:33Z (5 years ago)
From
Andrea Rossi at INAF <andrea.rossi@inaf.it>
A Rossi (INAF-OAS) report on behalf of the CIBO collaboration:
We observed the field of GRB 210306A (D'Elia et al., GCN 29597)
simultaneously in the r' and z' bands with the LBC imager mounted on LBT
(Mt Graham, AZ, USA). We obtained 20min of imaging on 2021-03-11, 5.06
days after the burst trigger. Observations were performed under good
weather conditions with an average seeing of ~1.2".
We clearly detect the afterglow and we preliminary measure
r=24.2+-0.2 (AB system),
calibrated against SDSS field stars. This is still in agreement with the
late decay index alpha~1.1 (after an initial plateau ending at ~2hours
after the burst trigger) obtained modelling the photometry available
(Strausbaugh et al., GCN29600; Zhu et al., GCN 29607; Hentunen &
Nissinen GCN 29603; Hosokawa et al., GCN29608; Dimple et al., GCN 29618;
Belkin et al., GCN 29616, GCN 29620