{
  "body": "Mankeun Jeong (SNU/SNUARC), Myungshin Im (SNU/SNUARC), Hyeonho Choi (SNU/SNUARC), and Seo-Won Chang (SNU/SNUARC) report on behalf of the 7-Dimensional Telescope collaboration\n\nWe observed the field of GRB 250706B/C (Palmerio et al., GCN 40989; Zhu et al., GCN 40991; Frederiks et al., GCN 41013; Longo et al., GCN 41019) using the 7-Dimensional Telescope (7DT). Observations were conducted on 2025 July 8 in multiple broadband and medium-band filters.\n\nWe performed forced photometry at the position of the UVOT optical counterpart (GCN 41015; RA = 02:44:53.43, Dec = −50:03:40.2, J2000), using a coadded image from all filters for source detection. Photometric calibration was performed using Gaia XP synthetic photometry (Gaia Collaboration et al. 2022).\n\nWe report a marginal detection only in the i-band, with a magnitude of i = 19.68±0.38 AB mag at T-T0 ≈ 1.84 days. The following table lists our photometric measurements (AB magnitudes). For non-detections, we provide 5σ upper limits:\n\nFilter   Mag (AB)        Exp(s)   UT Date-Obs           T−T₀ (days)\n-----------------------------------------------------------------------\ng        >19.90          300      2025-07-08 07:21:36    1.842\nr        >19.88          300      2025-07-08 07:26:58    1.846\ni        19.68 ± 0.38    1200     2025-07-08 07:38:17    1.841\nm400     >18.19          300      2025-07-08 07:27:01    1.846\nm450     >18.85          300      2025-07-08 07:21:33    1.842\nm475     >18.94          300      2025-07-08 07:26:58    1.846\nm550     >18.65          300      2025-07-08 07:21:40    1.842\nm575     >18.69          300      2025-07-08 07:27:08    1.846\nm600     >18.71          300      2025-07-08 07:21:41    1.842\nm625     >18.56          300      2025-07-08 07:27:15    1.846\nm650     >18.81          300      2025-07-08 07:21:34    1.842\nm675     >18.78          300      2025-07-08 07:26:57    1.846\nm700     >18.62          300      2025-07-08 07:21:29    1.841\nm725     >18.46          300      2025-07-08 07:26:50    1.846\nm750     >18.31          300      2025-07-08 07:21:36    1.842\nm775     >17.94          300      2025-07-08 07:26:59    1.846\nm800     >17.70          300      2025-07-08 07:21:43    1.842\nm825     >17.63          300      2025-07-08 07:27:13    1.846\nm850     >17.06          300      2025-07-08 07:21:31    1.842\nm875     >16.84          300      2025-07-08 07:21:37    1.842",
  "eventId": "GRB 250706B",
  "bibcode": "2025GCN.41087....1J",
  "submittedHow": "web",
  "submitter": "Mankeun Jeong <jmk5040@gmail.com>",
  "format": "text/plain",
  "createdOn": 1752476291498,
  "subject": "GRB 250706B/C: 7DT Follow-up Observations",
  "circularId": 41087
}