TITLE:   GCN CIRCULAR
NUMBER:  33623
SUBJECT: GRB 230414B: slow optical light curve decay
DATE:    23/04/14 23:47:27 GMT
FROM:    Daniele B Malesani at Radboud U  <d.malesani@astro.ru.nl>

D. B. Malesani (Radboud Univ. and DAWN/NBI), A. de Ugarte Postigo (OCA), 
L. Izzo (DARK/NBI), D. Xu (NAOC), Z.P. Zhu (NAOC, HUST), J. Acevedo 
Barroso (EPFL), C. Lemon (EPFL), Z. Gray (AOP), F. Neira (EPFL), report 
on behalf of a larger collaboration:

We observed the optical afterglow (Pankov et al., GCN 33615; Lu et al., 
GCN 33616; Raman et al., GCN 33618; Ghosh et al., GCN 33620; Moskvitin 
et al., GCN 33622) of GRB 230414B (D'Ai et al., GCN 33612) with the 
Nordic Optical Telescope (NOT) equipped with the ALFOSC imager. In a 
single r-band image obtained on 2023 Apr 14.95 UT (6.57 hr after the 
GRB), we clearly detect the optical afterglow at a magnitude r = 19.42 
+- 0.02 (AB), calibrated against nearby stars from the Pan-STARRS catalog.

Comparing to earlier magnitudes from the above mentioned GCNs, our 
measurement indicates a slow decay or plateau phase, as already hinted 
by the magnitudes reported by Moskvitin et al. (GCN 33622).