GRB 210504A: MITSuME Akeno optical upper limits
Abstract
We observed the field of GRB 210504A (Beardmore et al. GCN Circular #29929, Lien et al. GCN Circular #29930) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation with a series of 60 sec exposures started at 2021-05-04 14:55:16 UT (1.0 hour after the BAT trigger, Lien et al. GCN Circular #29930). We stacked the images with good conditions. We did not detect any uncatalogued sources within the XRT error circle (Beardmore et al. GCN Circular #29929) in all three bands. We obtained the 5-sigma limits of the stacked images as follows. T0+[hour] MID-UT T-EXP[sec] 5-sigma limits ------------------------------------------------------------------------------------------------ 1.1 2021-05-04 15:01 300 g'>15.9, Rc>16.2, Ic>15.9 2.8 2021-05-04 16:42 2580 g'>18.3, Rc>18.7, Ic>18.3 ------------------------------------------------------------------------------------------------ T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used the 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:
- May 2021
- Bibcode:
- 2021GCN.29936....1H