GCN Circular 39707
Subject
EP trigger ID 01709061302: Lick/Kast spectroscopy with the 3 m Shane telescope
Date
2025-03-13T19:38:57Z (21 days ago)
From
Weikang Zheng at UC Berkeley <weikang@berkeley.edu>
Via
email
WeiKang Zheng, Thomas G. Brink, Alexei V. Filippenko (UCB), Andy Skemer,
Naunet Leonhardes-Barboza, Jordan Forman, Mayra Gutierrez, Isabelle Jones,
Ravjit Kaur, Petra Mengistu, Avi Patel, Anavi Uppal, Nicole Wolff, and
Michele Woodland (UCSC), report on behalf of the KAIT GRB team:
We observed the K-type star PM J23221-0301, the possible optical counterpart
of an EP flare event (trigger ID 01709061302; Shui et al., GCN 37615), with
the Kast spectrograph on the 3 m Shane telescope at Lick Observatory.
Observations were performed on Sep. 27.164 UTC, about 2.79 hours after the
trigger, covering the 5800-7400 Ang wavelength range. The spectrum shows a
red continuum with narrow absorption lines consistent with a K-type star
spectrum. In particular, there is a very strong H-alpha emission line
in the spectrum.
Another spectrum of PM J23221-0301 was taken the following night on Sep.
28.320,
about 1.272 days after the trigger, covering the 3500-10,000 Ang wavelength
range. The H-alpha emission line had nearly faded away compared to the
previous
spectrum. We therefore confirm this to be the flare star related to the EP
flare event.
In addition, a new spectrum of star 2MASS J18351416+2435115 was taken on
Sep. 28.216. Compared with the spectrum taken 3 days earlier (Zheng et al.,
GCN
37618), the Balmer emission lines faded significantly, confirming this star
to be the flare star related to the EP flare event (trigger ID 01709059262;
Liu et al., GCN 37593, 37594).