GRB 221218A: MITSuME Akeno optical upper limits
Abstract
We observed the field of GRB 221218A (S. Mereghetti et al. GCN Circular #33082, WeiKang Zheng et al. GCN Circular #33085, Y.-D. Hu et al. GCN Circular #33086) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope Akeno. The observation with a series of 60 sec exposures started at 2022-12-18 08:37:35 UT (1405 seconds after the INTEGRAL trigger). We stacked the images with good conditions. We did not detect any uncatalogued sources within the error region (S. Mereghetti et al. GCN Circular #33082). We obtained the 5-sigma limits of the stacked images as follows. T0+[sec] | MID-UT | T-EXP[sec] | 5-sigma limits ------------------------------------------------------------------------------------------------ 1405 | 2022-12-18 08:51:23 | 1140.0 | g'>19.1, Rc>19.0, Ic>18.4 ------------------------------------------------------------------------------------------------ T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used PS1 catalog for flux calibration. The magnitudes are expressed in the AB system. The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1, Pages 4-24; https://github.com/MNiwano/Eclaire).
- Publication:
-
GRB Coordinates Network
- Pub Date:
- December 2022
- Bibcode:
- 2022GCN.33087....1T