GCN Circular 37228

WeiKang Zheng, Thomas G. Brink, Alexei V. Filippenko (UCB),

Rebecca Davies and Adam Deller (Swinburne),

report on behalf of the KAIT GRB team:


Following the detection of EP240801a (Zhou et al., GCN 36997
Not found
 
 
),

we observed its GRB optical counterpart (Fu et al., GCN 36998
Not found
 
 
;

Li et al., GCN 36999
Not found
 
 
; Zheng et al., GCN 37000
Not found
 
 
; Aryan et al.,

GCN 37002
Not found
 
 
; An et al., GCN 37004
Not found
 
 
; Pérez-Fournon et al., GCN

37007
Not found
 
 
; Malesani et al., GCN 37008
Not found
 
 
; Zhu et al., GCN 37010
Not found
 
 
;

Moskvitin & Spiridonova, GCN 37012
Not found
 
 
; Quirola-Vásquez et al.,

GCN 37013
Not found
 
 
; Moretti et al., GCN 37014
Not found
 
 
; Turpin et al., GCN 37015
Not found
 
 
;

Pankov et al., GCN 37016
Not found
 
 
; Moskvitin & Spiridonova, GCN 37017
Not found
 
 
;

Ruocco et al., GCN 37024
Not found
 
 
; Pankov et al., GCN 37040
Not found
 
 
; Moskvitin

et al., GCN 37049
Not found
 
 
; Pankov et al., GCN 37146
Not found
 
 
) with the Low

Resolution Imaging Spectrometer (LRIS, Oke et al. 1995) at the

Keck I Observatory (ToO program U232, PI A. V. Filippenko).

Observations started at 2024-08-02 09:36 (~1.02 days after the

burst), and consisted of 3 x 950 s exposures with the 600/4000

grism and 400/8500 grating. The spectrum shows a well-detected

continuum. We detect narrow absorption lines consistent with

Mg II 2796, 2803 Ang doublet as well as Fe II 2600 Ang,

confirming the redshift of z = 1.673 reported by Quirola-Vásquez

et al. (GCN 37013
Not found
 
 
) from GTC.


We thank Josh Walawender and Matthew Wahl from the Keck team for

their support during this Target of Opportunity trigger. The data

presented herein were obtained at the W. M. Keck Observatory,

which is operated as a scientific partnership among the California

Institute of Technology, the University of California, and the

National Aeronautics and Space Administration. The Observatory was

made possible by the generous financial support of the W. M. Keck

Foundation. The authors wish to recognize and acknowledge the very

significant cultural role and reverence that the summit of Maunakea

has always had within the indigenous Hawaiian community. We are

most fortunate to have the opportunity to conduct observations from

this mountain.