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GCN Circular 36175

GRB 240419A: VLT optical afterglow detection
2024-04-19T08:17:24Z (3 months ago)
Daniele B. Malesani at IMAPP / Radboud University <>
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B. Schneider (MIT), N. Gaspari (Radboud Univ.), N. R. Tanvir (Univ. Leicester), S. Covino (INAF/Brera), D. B. Malesani (DAWN/NBI and Radboud Univ.), L. Izzo (INAF/Napoli and DARK/NBI), A. Saccardi (GEPI/Obs. Paris), report on behalf of the Stargate collaboration.

We observed the field of GRB 240419A (Siegel et al., GCN 36169) using the ESO VLT UT1 equipped with the FORS2 camera. Observations were commenced automatically in rapid-response mode (RRM). The first image was acquired on April 19.0895 UT, that is, 20.9 min after the GRB, and consisted of a 20 s image in the R filter. At a relatively high airmass of 2.1, the delivered PSF was 1.4".

A source, not present in archival images, is detected within the UVOT-enhanced XRT error circle (Goad et al., GCN 36174), at coordinates (J2000):

RA = 06:18:08.17
Dec = -44:59:57.3

Using FORS2 zeropoints, we measure for the source a magnitude R = 19.88 +- 0.05 (Vega), in excellent agreement with photometry calibrated against nearby stars from the SkyMapper catalog.

Further observations have been secured and will be reported at a later time. We acknowledge excellent support from the ESO observing staff in Paranal.
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