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GCN Circular 33230

Subject
ZTF23aabmzlp/AT2023azs: GIT confirmation of the likely afterglow
Date
2023-01-28T19:08:22Z (a year ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar (IITB), V. Swain (IITB), R. Norbu (IAO), G. Waratkar (IITB), V.
Bhalerao (IITB), G. C. Anupama(IIA), S. Barway (IIA) report on behalf of
the GIT team:

We observed ZTF23aabmzlp/AT2023azs discovered by Zwicky Transient Facility
(Andreoni et al., GCN #33229), with 0.7m GROWTH-India Telescope (GIT). We
obtained three exposures of 300sec each in the g', r', and i' filters. We
clearly detected the candidate in our stacked images. The photometric
results follow as:-

-------------------------------------------------------------------

 JD (mid) | Filter | Magnitude (AB) |

-------------------------------------------------------------------

2459973.224114 | g' | 20.48 +/- 0.07 |

2459973.235212 | r' | 20.31 +/- 0.06 |
2459973.248096 | i' | 19.79 +/- 0.20 |
-------------------------------------------------------------------

GIT observations imply that the source continues fading and is redder in
colour. Comparing our g' and r' observations with ZTF (Andreoni et al., GCN
#33229), we compute a power-law decay index of ~0.7, further strengthening
the claim that the candidate is an afterglow. Candidate follow-up is
encouraged. The magnitudes are calibrated against PanSTARRS DR1 (Chambers
et al., 2016) and not corrected for Galactic extinction.

The GROWTH India Telescope (GIT; Kumar et al. 2022
<https://iopscience.iop.org/article/10.3847/1538-3881/ac7bea>) is a 70-cm
telescope with a 0.7-degree field of view, set up by the Indian Institute
of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB)
with funding from DST-SERB and IUSSTF. It is located at the Indian
Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding
by the IITB alumni batch of 1994, which partially supports operations of
the telescope. Telescope technical details are available at
https://sites.google.com/view/growthindia/.
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