TITLE:   GCN CIRCULAR
NUMBER:  39785
SUBJECT: LIGO/Virgo/KAGRA S250206dm: LIGHETR followup observations of AT2025azn
DATE:    25/03/19 17:15:20 GMT
FROM:    Hsin-Yu Chen at The University of Texas at Austin <hsinyu@austin.utexas.edu>

Hsin-Yu Chen (UT Austin), Greg Zeimann (UT McDonald Observatory), J. Craig Wheeler (UT Austin), and Jozsef Vinko (Konkoly Observatory) report on behalf of the LIGHETR Collaboration:

We conducted targeted follow-up observations of AT 2025azn (Hosseinzadeh et al., GCN 39191), a potential electromagnetic counterpart to the LIGO/Virgo/KAGRA gravitational-wave event S250206dm (LVK Collaboration, GCN 39175), using the Low Resolution Spectrograph (LRS2) on the Hobby-Eberly Telescope (HET) [1].

The observations were carried out 9 to 14 days after the gravitational-wave event and consisted of two 1800s exposures with LRS2-R (covering 650–842 nm and 818–1050 nm) and two 1800s exposures with LRS2-B (covering 370–470 nm and 460–700 nm) [2].

Our preliminary analysis did not reveal any emission beyond that of the host galaxy. Further analysis is ongoing.

[1] Bustamante Rosell et al, ApJ (2023)
[2] Chonis et al, Proceedings of the SPIE (2014)