LVK S240422ed: Further Swift-XRT followup of three sources
Abstract
Swift has conducted follow-up observations of sources S240422ed_X61, S240422ed_X101 and S240422ed_X190, reported in GCN Circ. 36278. All three sources are now undetected with fading confirmed at at least the 3-sigma level. On close inspection, we now believe that source S240422ed_X190 is not a real X-ray object. The XRT was operating at a higher-than-normal temperature when that object was detected and the image has an abnormally high background; further, the PSF of the source is not consistent with that expected for the reported count-rate, we thus believe this object can be dismissed. Source S240422ed_X61 was detected initially with a count rate of (8.3 +/- 3.0) x 10^-2 ct s^-1; in the latest observation it is undetected with a 3-sigma upper limit of 1.02 x 10^-2 ct s^-1. Source S240422ed_X101 was detected initially with a count rate of 0.10 +/- 0.03 ct s^-1; in the latest observation it is undetected with a 3-sigma upper limit of 1.05 x 10^-2 ct s^-1. Both of these sources were also initially detected while the XRT temperature was elevated; however, there is no evidence of significantly increased background in those observations.
- Publication:
-
GRB Coordinates Network
- Pub Date:
- April 2024
- Bibcode:
- 2024GCN.36314....1E