TITLE:   GCN CIRCULAR
NUMBER:  36183
SUBJECT: GRB 240419A: REM NIR afterglow detection
DATE:    24/04/19 15:36:10 GMT
FROM:    Matteo Ferro at INAF-OAB <matteo.ferro@inaf.it>

M. Ferro, Y.-D. Hu, P. D’Avanzo, R. Brivio, S. Covino, D. Fugazza (INAF-OAB) on behalf of the REM team, report:

We observed for the field of GRB 240419A (Siegel et al., GCN 36169) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H, K bands, starting on 2024 April 19 at 01:49:38 UT (i.e. 1.6 minutes after the event), and lasting for about 3 hours.
From preliminary photometry we detect the  NIR afterglow at a position consistent with the optical afterglow position (Schneider et al., GCN 36175), at the following AB magnitude in the H band:

H = 15.7 +- 0.1 (calibrated against 2MASS catalogue)
at a mid time of t-t0 ~ 4 minutes after the GRB trigger.

The afterglow is not detected in our optical observations, at the following AB magnitude limit in the r band:

r > 19.2 (calibrated against SkyMapper catalogue)
at a mid time of t-t0 ~ 6.3 minutes after the GRB trigger.