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GCN Circular 36287

LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
2024-04-24T19:05:49Z (3 months ago)
Gaurav Waratkar at IIT Bombay <>
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V. Swain (IITB), G. Waratkar (IITB), U. Pathak (IITB), A. Salgundi (IITB), A. Suresh (IITB), J. Basu (IIA), R.S. Teja (IIA), G. C. Anupama (IIA), S. Barway (IIA), V. Bhalerao (IITB), D.K. Sahu (IIA), A. Suryaprakash (IIA-CREST):

We observed the field of the rank 2 source S240422ed_X101 detected by Swift/XRT (Evans et al., GCN Circ. 36278) with the 2m Himalayan Chandra Telescope (HCT). The observation started at 2024-04-24T14:24:21 UT, i.e., 1.7 days after the LVK trigger (GCN Circ. 36236). We obtained multiple frames in the SDSS i' filter with different exposure times adding up to 55 minutes. Photometry was calibrated against PanSTARRS DR1 (Chambers et al., 2016).

We searched individual images as well as the stacked image but did not detect any afterglow within the Swift/XRT uncertainty circle. We obtain an upper limit of 21.8 mag (5 sigma) in our stacked image. 

These observations were carried out under the ToO program HCT-2024-C1-P56. 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.

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