TITLE: GCN CIRCULAR NUMBER: 26787 SUBJECT: LIGO/Virgo S200114f: Swift-XRT sources and observations DATE: 20/01/16 14:39:16 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), S.D. Barthelmy (NASA/GSFC), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), A.A. Breeveld (UCL-MSSL), P. Brown (TAMU), D.N. Burrows (PSU), S. Campana (INAF-OAB), S.B. Cenko (NASA/GSFC), G. Cusumano (INAF-IASF PA), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), V. D'Elia(ASDC), S.W.K. Emery (UCL-MSSL), P. Giommi (ASI), C. Gronwall (PSU), D. Hartmann (U. Clemson), H.A. Krimm (CRESST/GSFC/USRA), N.J. Klingler (PSU), N.P.M. Kuin (UCL-MSSL), A.Y. Lien (GSFC/UMBC), F.E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), J.A. Nousek (PSU), S.R. Oates (U. Birmingham), P.T. O'Brien (U. Leicester), J.P. Osborne (U. Leicester), C. Pagani (U. Leicester), K.L. Page (U.Leicester), M.J.Page (UCL-MSSL), D.M. Palmer (LANL), M. Perri (ASDC), J.L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU), M.H. Siegel (PSU), G. Tagliaferri (INAF-OAB), E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team: Swift has carried out 206 observations of the LVC error region for the GW trigger S200114f following the 'cWB' (version 3) GW localisation map. The observations currently span from 6.6 ks to 99 ks after the LVC trigger, and the XRT has covered 22.3 deg^2 on the sky (corrected for overlaps). This covers 30% of the probability in the 'cWB' (version 3) skymap. These pointings and associated metadata have been reported to the Treasure Map (Wyatt et al., arXiv 2001.00588; http://treasuremap.space/alerts?graceids=S200114f). A 'rank 2' source has been found, so classified because it shows indications of fading, however it is spatially consistent with a source in the WISE AGN candidates catalogs (Assef et al., 2018) and therefore may simply be a variable AGN. The details of this source are: Source 2: ============= RA: 110.3641 ( = 07h 21m 27.38s) J2000 Dec: +17.0360 ( = +17d 02' 09.6") J2000 Error: 7.0 (arcsec, radius, 90% confidence). Peak Rate: 9.6e-02 +/- 1.7e-02 ct/sec (0.3-10 keV) Peak Flux: 4.1e-12 +/- 7.5e-13 erg cm^-2 s^-1 (0.3-10 keV) Catalogued: No RASS UL: 3.5e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV) Further observations of this source are scheduled. In total, we have detected 8 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 * 1 source of rank 2 * 6 sources of rank 3 * 1 source 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 | | S200114f_X1 | 07h 13m 48.09s | +23d 04' 50.5" | 7.5" | | S200114f_X10 | 03h 41m 58.28s | -25d 24' 17.6" | 6.1" | | S200114f_X46 | 03h 41m 1.50s | -25d 26' 54.4" | 6.4" | | S200114f_X56 | 07h 22m 51.63s | +16d 15' 51.0" | 6.3" | | S200114f_X57 | 07h 23m 54.09s | +16d 22' 00.1" | 7.7" | | S200114f_X58 | 07h 23m 50.42s | +16d 21' 17.1" | 6.7" | 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 | | S200114f_X59 | 07h 15m 9.23s | +15d 55' 36.9" | 8.3" | The Swift-XRT observations also covered the locations of 6 sources reported by other observers, thus: * AT2020vr (GCN26741) F < 3.3x10^-12 erg cm^-2 s^-1. * AT2020vs (GCN26741) F < 2.0x10^-12 erg cm^-2 s^-1. * AT2020vt (GCN26741) F < 4.2x10^-12 erg cm^-2 s^-1. * AT2020vu (GCN26741) F < 8.6x10^-12 erg cm^-2 s^-1. * AT2020vw (GCN26741) F < 4.7x10^-12 erg cm^-2 s^-1. * AT2020wc (GCN26741) F < 1.7x10^-11 erg cm^-2 s^-1. Flux limits are 3-sigma upper limits on the 0.3-10 keV observed flux. 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 The results of the XRT automated analysis, including details of the sources listed above, are online at https://www.swift.ac.uk/LVC/S200114f This circular is an official product of the Swift XRT team.