LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
Abstract
Swift has carried out 18 observations to tile the location of MAXI J2215+39, a possible counterpart to the subthreshold GW trigger S230917af (Negoro et al., GCN Circ. 34723). We have detected 6 X-ray sources. Each source is assigned a rank of 1-4 which describes how likely it is to be related to the GW trigger, with 1 being the most likely and 4 being the least likely. The ranks are described at https://www.swift.ac.uk/ranks.php. We have found: * 0 sources of rank 1 * 0 sources of rank 2 * 1 source of rank 3 * 5 sources of rank 4 RANK 3 sources ============== These are uncatalogued X-ray sources, however they are not brighter than previous upper limits, so do not stand out as likely counterparts to the GW trigger. | Source ID | RA | Dec | Err90 | | S230917af_X3 | 22h 13m 08.28s | +39d 32' 46.1" | 8.4" | RANK 4 sources ============== These are catalogued X-ray sources, showing no signs of outburst compared to previous observations, so they are not likely to be related to the GW trigger. | Source ID | RA | Dec | Err90 | | S230917af_X1 | 22h 17m 41.91s | +39d 19' 22.3" | 5.1" | | S230917af_X4 | 22h 14m 05.23s | +39d 38' 57.2" | 5.4" | | S230917af_X6 | 22h 16m 33.47s | +39d 51' 41.1" | 7.2" | | S230917af_X9 | 22h 13m 43.20s | +38d 55' 20.3" | 6.3" | | S230917af_X10 | 22h 14m 50.64s | +38d 51' 07.1" | 6.7" | For all flux conversions and comparisons with catalogues and upper limits from other missions, we assumed a power-law spectrum with NH=3x10^20 cm^-2, and photon index (Gamma)=1.7, unless otherwise stated. The results of the XRT automated analysis, including details of the sources listed above, are online at https://www.swift.ac.uk/LVC/S230917af Further observations of S230917af_X3 have been requested. This circular is an official product of the Swift XRT team.
- Publication:
-
GRB Coordinates Network
- Pub Date:
- September 2023
- Bibcode:
- 2023GCN.34736....1E