{
  "bibcode": "2024GCN.38382....1A",
  "submitter": "Dalya Akl at American Uni. SHJ <dalyaakl.d@gmail.com>",
  "circularId": 38382,
  "version": 2,
  "submittedHow": "web",
  "subject": "GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits",
  "body": "D. Akl (AUS), E. de Bruin  (UMN), C. Andrade (UMN), M. Tanasan (NARIT), N. Kochiashvili (AbAO), T. Hussenot-Desenonges (IJCLAB), M. Coughlin (UMN), M. Molham (NRIAG), S. Agayeva (Shamakhy Obs.), \nS. Antier (OCA), S. Karpov (FZU), D. Turpin (CEA-Saclay/Irfu), I. Tosta e Melo (UniCT-DFA), P. Hello (IJCLAB), P-A Duverne (APC), T. Pradier (Unistra/IPHC), N. Guessoum (AUS), M. Masek (FZU), A. Klotz (IRAP), M. Boer, S. Gervasoni, C. Limonta (OCA), E. Broens, F. Kugel (KNC), on behalf of the GRANDMA and Kilonova-Catcher collaborations:\n\nWe observed the field of GRB 241128A (Brivio et al., GCN 38367) detected by Swift-BAT with GRANDMA and its citizen science project Kilonova-catcher (KNC). Our observations were performed with the FRAM-CTA-N, TAROT-TCA, KNC T400, and KNC-T-BRO telescopes starting from TGRB+108 min. \n\nWe clearly detect the optical afterglow within the Swift-XRT uncertainty region (Beardmore et al., GCN 38374) and obtain the following magnitudes and 5-sigma upperlimits:\n+---------------------+-------------+--------+----------------+------------+\n| T-mid(UTC)          | Exposure(s) | Filter | Mag (AB)       | Instrument |\n+=====================+=============+========+================+============+\n| 2024-11-28T18:02:48 | 27x60       | Clear  | 19.50 +/- 0.07 | KNC        | \n| 2024-11-28T18:11:15 | 7x180       | Clear  | 19.78 +/- 0.22 | KNC        | \n| 2024-11-28T18:38:26 | 11x180      | Clear  | 19.67 +/- 0.19 | KNC        |\n| 2024-11-28T19:31:58 | 18x120      | R      | 17.84 (U.L.)   | FRAM-CTA-N |\n| 2024-11-28T19:40:56 | 3x180       | Clear  | 17.53 (U.L.)   | TAROT-TCA  |\n+---------------------+-------------+--------+----------------+------------+\n\nOur detection is consistent with the optical afterglow detected and reported by Hu et al., GCN 38371.\nFurther, our magnitudes are consistent with those reported by LCO (Izzo and Malesani, GCN 38372) and NOT (Gompertz et al., GCN 38373).  \n\nAll the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022). Images obtained in Johnson Cousin filters were calibrated using the Gaia DR3 Synphot catalog, while images taken with a clear filter were calibrated using the Gaia eDR3 Catalog.\n\nWe use the SkyPortal application (skyportal.io) to monitor our observational campaign (Coughlin et al. 2023). \n\nGRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/).",
  "editedBy": "Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Dalya Akl at American Uni. SHJ <dalyaakl.d@gmail.com>",
  "editedOn": 1732913761513,
  "eventId": "GRB 241128A",
  "format": "text/plain",
  "createdOn": 1732893901422
}