TITLE: GCN CIRCULAR NUMBER: 38150 SUBJECT: EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory DATE: 24/11/10 00:34:38 GMT FROM: Weikang Zheng at UC Berkeley <weikang@berkeley.edu> WeiKang Zheng, Ryan Chornock, Natalie LeBaron, Xinze Guo, William Wu Alexei V. Filippenko (UCB), and Xuhui Han, Pinpin Zhang (NAOC) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, automatically responded to EP241109a (Li et al., GCN 38140) starting at 06:09 UT, 7 minutes after the trigger. A set of images with 20s exposure time were obtained in B, V, R I and clear (roughly R) filters. Observations lasted for about 3.5 hours. We detected the flare star reported by Perez-Garcia et al. (GCN 38141) in all our images. Photometry of the star show that its brightness decreased from the start of our observation in all filters, especially in B band which decreased by nearly 3 mag. The light curves became flat after about 2.5 hours after trigger in all bands. A spectrum was also taken with the Kast spectrograph on the 3 m Shane telescope at Lick Observatory. Observations was performed at about 2.3 hours after the trigger, covering the 3500-10,000 A wavelength range, with an exposure time of 300s. The spectrum shows a red continuum flux overlapped with strong Balmer emission lines as well as Ca II H&K and TiO emission lines, consistent with a typical dMe star spectrum. The flux below ~4000A show a bit excess, which might be caused by the flare, compared with the typical dMe star spectrum at quiescent time. Based on the above photometry and spectroscopy results, we therefore confirm that this EP241109a event is truly associated with this stellar flare. View this GCN Circular online at https://gcn.nasa.gov/circulars/38150. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...