{
  "subject": "EP250108a/AT2025kg: 1.3m DFOT Optical observations",
  "submitter": "Amit Kumar Ror at ARIES <mitturor77894@gmail.com>",
  "body": "Amit K. Ror, Anshika Gupta, Kiran, Shashi B. Pandey, Kuntal Mishra (ARIES)\nreport:\n\nWe observed the field of EP250108a detected by the Wide-field X-ray\nTelescope on board the Einstein Probe (Einstein Probe team, Li et al. 2025,\nGCN 38861), with the 1.3m Devasthal Fast Optical Telescope (DFOT), located\nat the Devasthal Observatory of the Aryabhatta Research Institute of\nObservational Sciences (ARIES), India. The observations were started on\n2025-01-19 at 16:15:38 UT, i.e., ~ 11.16 days after the Einstein Probe\ntrigger. We have taken multiple frames with an exposure time of 300 s in\nthe R filter. We stacked the images after the alignment. We detected an\noptical emission in our stacked image at the position of the optical\ncounterpart candidate EP250108a / AT 2025kg by Eyles-Ferris et al. (2025,\nGCN 38878). We obtain the following preliminary magnitude in the stacked\nimage:\n\nDate Start_UT T_start-T0 (days) Filter  Exp time (s)  Magnitude\n==================================================\n2025-01-19 16:15:38     ~11.16     R     300s*12     19.89 +/- 0.04\n\nOur detection is consistent with Lipunov et al. 2025, GCN 38865;\nEyles-Ferris et al. 2025, GCN 38878; Zhu et al. 2025, GCN 38885; Junjie-Jin\net al. 2025, GCN 38891; Malesani et al. 2025, GCN 38902; Kumar et al. 2025,\nGCN 38907; Zhu et al. 2025, GCN 38908; Levan et al. 2025, GCN 38909; Izzo\net al. 2025, GCN 38912; Zou et al. 2025, GCN 38914; Moskvitin et al. 2025,\nGCN 38925; Zhu et al. 2025, GCN 38937; Carotenuto et al. 2025, GCN 38958;\nSchroeder et al. 2025, GCN 38970; Song et al. 2025, GCN 38972; Eyles-Ferris\net al. 2025, GCN 38983; Xu et al. 2025, GCN 38984; Levan et al. 2025, GCN\n38987; and Tao et al. 2025, GCN 38998.\n\nThe magnitude is not corrected for the Galactic extinction in the direction\nof the burst. Photometric calibration is performed using the standard stars\nfrom the USNO-B1.0 catalogue. This circular may be cited.\n",
  "circularId": 39002,
  "createdOn": 1737391099598,
  "eventId": "EP250108a",
  "submittedHow": "email",
  "bibcode": "2025GCN.39002....1R"
}