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GCN Circular 21844

Subject
LIGO/Virgo G299232: Swift-XRT sources
Date
2017-09-07T13:12:46Z (7 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans (U. Leicester), J.A. Kennea (PSU), S.D. Barthelmy
(NASA/GSFC), A.P. Beardmore (U. Leicester), A.A. Breeveld (UCL-MSSL),
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), H.A. Krimm (CRESST/GSFC/USRA), 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. Warwick), P.T. O'Brien (U. Leicester),
J.P. Osborne (U. Leicester), C. Pagani (U. Leicester), K.L. Page
(U.Leicester), 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), A. Tohuvavohu (PSU), E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift team:

Swift has performed a series of 768 observations, covering 653 separate
locations within the LVC error region for the GW trigger G299232
convolved with the 2MPZ catalogue (Bilicki et al. 2014, ApJS, 210, 9),
using the 'bayestar-HLV' GW localisation map. As this is a 3D skymap,
galaxy distances were taken into account in selecting which ones to
observe. The observations currently span from 11 ks to 758 ks after the
LVC trigger, and cover 75.9 sq degrees on the sky (corrected for
overlaps). This covers 8.3% of the probability in the 'bayestar-HLV'
skymap, and 15% after convolving with the 2MPZ galaxy catalogue, as
described by Evans et al., (2016, MNRAS,  462, 1591). A list of all
observations and exposure times is in GraceDB.

In total, we have detected 51 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 http://www.swift.ac.uk/ranks.php.

We have found:

  * 0 sources of rank 1
  * 1 source of rank 2
  * 30 sources of rank 3
  * 20 sources of rank 4

For all flux conversions and comparisons with catalogues and upper
limits from other missions, we assumed a power-law spectrum with
NH=3e20 cm^2, and photon index (Gamma)=1.7

RANK 2 source
=============

This is a catalogued X-ray source which was detected at a level well
above the catalogued flux. However, this is an RS CVn variable star, so
this is not surprising. We do not consider this the counterpart.

  
  Source 11:
  =============
    RA: 	 26.7914 ( = 01h 47m 9.94s) J2000
    Dec:	 +23.7585 ( = +23d 45' 30.6") J2000
    Error:	 +4.1 (arcsec, radius, 90% confidence).
    Peak Rate:	 7.6e-02 +/- 1.5e-02 ct/sec (0.3-10 keV)
    Peak Flux:	 3.3e-12 +/- 6.3e-13 erg cm^-2 s^-1 (0.3-10 keV)
    Catalogued:  Yes
    Cat Source:  1RXS J014709.9+234529 in the ROSAT/RASSFSC catalogue
    Separation:  1.7" from the XRT source
    Cat Rate:	 2.6e-02 +/- 1.1e-02 ct/sec 
    Cat Flux:	 7.3e-13 +/- 3.0e-13 erg cm^-2 s^-1 (0.3-10 keV)
		 so the source	is 3.6-sigma above the catalogued flux.

    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW 

      object.
    A SIMBAD object `V* BE Ari' is 4.1" away.
    There is 1 2MASS object within the source's 3-sigma error radius.


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 7:
  =============
    RA: 	 28.8331 ( = 01h 55m 19.94s) J2000
    Dec:	 +41.4501 ( = +41d 27' 00.4") J2000
    Error:	 +6.1 (arcsec, radius, 90% confidence).
    Peak Rate:	 2.0e-02 +/- 1.2e-02 ct/sec (0.3-10 keV)
    Peak Flux:	 8.7e-13 +/- 5.3e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 3.7e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    There is 1 GWGC or 2MPZ galaxy within 200 kpc of the source.

      and consistent (within 3-sigma) with the distance to the GW
object.
  
  Source 8:
  =============
    RA: 	 57.4297 ( = 03h 49m 43.13s) J2000
    Dec:	 +75.2688 ( = +75d 16' 07.7") J2000
    Error:	 +5.9 (arcsec, radius, 90% confidence).
    Peak Rate:	 1.7e-02 +/- 7.3e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 7.4e-13 +/- 3.1e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 2.6e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    There are 2 GWGC or 2MPZ galaxies within 200 kpc of the source.
      and consistent (within 3-sigma) with the distance to the GW
object.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 9:
  =============
    RA: 	 26.4272 ( = 01h 45m 42.53s) J2000
    Dec:	 +32.7277 ( = +32d 43' 39.7") J2000
    Error:	 +6.8 (arcsec, radius, 90% confidence).
    Peak Rate:	 2.8e-02 +/- 1.1e-02 ct/sec (0.3-10 keV)
    Peak Flux:	 1.2e-12 +/- 4.6e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 2.2e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 13:
  =============
    RA: 	 275.5870 ( = 18h 22m 20.88s) J2000
    Dec:	 -24.5012 ( = -24d 30' 04.3") J2000
    Error:	 +6.9 (arcsec, radius, 90% confidence).
    Peak Rate:	 2.2e-02 +/- 9.4e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 9.6e-13 +/- 4.0e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 6.4e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    A SIMBAD object `PMN J1822-2429' is 3.9" away.
    There are 3 2MASS objects within the source's 3-sigma error radius.

  
  Source 14:
  =============
    RA: 	 280.4037 ( = 18h 41m 36.89s) J2000
    Dec:	 -26.9052 ( = -26d 54' 18.7") J2000
    Error:	 +6.5 (arcsec, radius, 90% confidence).
    Peak Rate:	 1.3e-02 +/- 4.7e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 5.5e-13 +/- 2.0e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 4.3e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    There are 2 2MASS objects within the source's 3-sigma error radius.

  
  Source 15:
  =============
    RA: 	 30.5062 ( = 02h 02m 1.49s) J2000
    Dec:	 +39.7221 ( = +39d 43' 19.6") J2000
    Error:	 +7.5 (arcsec, radius, 90% confidence).
    Peak Rate:	 1.7e-02 +/- 7.2e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 7.4e-13 +/- 3.1e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 4.2e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    There is 1 GWGC or 2MPZ galaxy within 200 kpc of the source.

      and consistent (within 3-sigma) with the distance to the GW
object.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 16:
  =============
    RA: 	 30.8523 ( = 02h 03m 24.55s) J2000
    Dec:	 +39.8555 ( = +39d 51' 19.8") J2000
    Error:	 +7.9 (arcsec, radius, 90% confidence).
    Peak Rate:	 4.2e-02 +/- 3.1e-02 ct/sec (0.3-10 keV)
    Peak Flux:	 1.8e-12 +/- 1.3e-12 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 2.4e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    The source may be fading, at the 1.2-sigma level.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 18:
  =============
    RA: 	 277.0265 ( = 18h 28m 6.36s) J2000
    Dec:	 -26.7567 ( = -26d 45' 24.1") J2000
    Error:	 +6.0 (arcsec, radius, 90% confidence).
    Peak Rate:	 2.5e-02 +/- 9.8e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 1.1e-12 +/- 4.2e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 6.3e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    A SIMBAD object `HD 169938' is 3.5" away.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 20:
  =============
    RA: 	 21.1039 ( = 01h 24m 24.94s) J2000
    Dec:	 +8.4009 ( = +08d 24' 03.2") J2000
    Error:	 +5.2 (arcsec, radius, 90% confidence).
    Peak Rate:	 3.3e-02 +/- 1.0e-02 ct/sec (0.3-10 keV)
    Peak Flux:	 1.4e-12 +/- 4.3e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 4.7e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    There is 1 GWGC or 2MPZ galaxy within 200 kpc of the source.

      and consistent (within 3-sigma) with the distance to the GW
object.
    A SIMBAD object `2MASS J01242495+0824076' is 4.5" away.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 23:
  =============
    RA: 	 280.4462 ( = 18h 41m 47.09s) J2000
    Dec:	 -31.1682 ( = -31d 10' 05.5") J2000
    Error:	 +5.5 (arcsec, radius, 90% confidence).
    Peak Rate:	 2.9e-02 +/- 9.7e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 1.2e-12 +/- 4.2e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 3.2e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 24:
  =============
    RA: 	 280.4270 ( = 18h 41m 42.48s) J2000
    Dec:	 -31.1927 ( = -31d 11' 33.7") J2000
    Error:	 +4.6 (arcsec, radius, 90% confidence).
    Peak Rate:	 5.0e-02 +/- 1.2e-02 ct/sec (0.3-10 keV)
    Peak Flux:	 2.1e-12 +/- 5.1e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 3.5e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 25:
  =============
    RA: 	 35.0606 ( = 02h 20m 14.54s) J2000
    Dec:	 +50.7456 ( = +50d 44' 44.2") J2000
    Error:	 +9.8 (arcsec, radius, 90% confidence).
    Peak Rate:	 2.0e-02 +/- 7.8e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 8.6e-13 +/- 3.3e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 2.9e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    There are 2 2MASS objects within the source's 3-sigma error radius.

  
  Source 27:
  =============
    RA: 	 35.3623 ( = 02h 21m 26.95s) J2000
    Dec:	 +51.4366 ( = +51d 26' 11.8") J2000
    Error:	 +5.1 (arcsec, radius, 90% confidence).
    Peak Rate:	 1.3e-02 +/- 4.6e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 5.4e-13 +/- 2.0e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 1.5e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 29:
  =============
    RA: 	 20.0708 ( = 01h 20m 16.99s) J2000
    Dec:	 +12.0556 ( = +12d 03' 20.2") J2000
    Error:	 +6.1 (arcsec, radius, 90% confidence).
    Peak Rate:	 1.3e-02 +/- 4.9e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 5.7e-13 +/- 2.1e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 9.8e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    A SIMBAD object `NVSS J012016+120326' is 6" away.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 30:
  =============
    RA: 	 25.0723 ( = 01h 40m 17.35s) J2000
    Dec:	 +23.4559 ( = +23d 27' 21.2") J2000
    Error:	 +6.4 (arcsec, radius, 90% confidence).
    Peak Rate:	 2.0e-02 +/- 7.8e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 8.6e-13 +/- 3.3e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 1.6e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    A SIMBAD object `2MASS J01401722+2327211' is 1.6" away.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 32:
  =============
    RA: 	 29.7004 ( = 01h 58m 48.10s) J2000
    Dec:	 +36.3610 ( = +36d 21' 39.6") J2000
    Error:	 +5.1 (arcsec, radius, 90% confidence).
    Peak Rate:	 2.4e-02 +/- 8.6e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 1.0e-12 +/- 3.7e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 3.6e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    There are 3 GWGC or 2MPZ galaxies within 200 kpc of the source.
      and consistent (within 3-sigma) with the distance to the GW
object.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 34:
  =============
    RA: 	 30.2909 ( = 02h 01m 9.82s) J2000
    Dec:	 +44.1712 ( = +44d 10' 16.3") J2000
    Error:	 +5.8 (arcsec, radius, 90% confidence).
    Peak Rate:	 1.8e-02 +/- 7.7e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 7.9e-13 +/- 3.3e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 4.9e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 36:
  =============
    RA: 	 30.1611 ( = 02h 00m 38.66s) J2000
    Dec:	 +44.4550 ( = +44d 27' 18.0") J2000
    Error:	 +5.7 (arcsec, radius, 90% confidence).
    Peak Rate:	 1.3e-02 +/- 6.0e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 5.6e-13 +/- 2.6e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 2.8e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    A SIMBAD object `4C 44.05' is 4.2" away.
  
  Source 41:
  =============
    RA: 	 35.7720 ( = 02h 23m 5.28s) J2000
    Dec:	 +43.5135 ( = +43d 30' 48.6") J2000
    Error:	 +6.1 (arcsec, radius, 90% confidence).
    Peak Rate:	 2.2e-02 +/- 7.5e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 9.4e-13 +/- 3.2e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 7.6e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 43:
  =============
    RA: 	 25.0451 ( = 01h 40m 10.82s) J2000
    Dec:	 +34.5945 ( = +34d 35' 40.2") J2000
    Error:	 +7.6 (arcsec, radius, 90% confidence).
    Peak Rate:	 4.3e-03 +/- 3.3e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 1.9e-13 +/- 1.4e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 2.4e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    The source may be fading, at the 0.3-sigma level.
    There are 3 GWGC or 2MPZ galaxies within 200 kpc of the source.
      and consistent (within 3-sigma) with the distance to the GW
object.
  
  Source 44:
  =============
    RA: 	 24.9350 ( = 01h 39m 44.40s) J2000
    Dec:	 +34.6730 ( = +34d 40' 22.8") J2000
    Error:	 +6.4 (arcsec, radius, 90% confidence).
    Peak Rate:	 4.1e-03 +/- 2.6e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 1.8e-13 +/- 1.1e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 2.0e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    The source may be fading, at the 0.6-sigma level.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 45:
  =============
    RA: 	 25.0033 ( = 01h 40m 0.79s) J2000
    Dec:	 +34.5832 ( = +34d 34' 59.5") J2000
    Error:	 +5.7 (arcsec, radius, 90% confidence).
    Peak Rate:	 3.2e-03 +/- 1.7e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 1.4e-13 +/- 7.5e-14 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 2.5e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    There are 3 GWGC or 2MPZ galaxies within 200 kpc of the source.
      and consistent (within 3-sigma) with the distance to the GW
object.
  
  Source 46:
  =============
    RA: 	 25.0002 ( = 01h 40m 0.05s) J2000
    Dec:	 +34.6823 ( = +34d 40' 56.3") J2000
    Error:	 +6.4 (arcsec, radius, 90% confidence).
    Peak Rate:	 4.2e-03 +/- 2.0e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 1.8e-13 +/- 8.7e-14 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 2.0e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    There are 2 GWGC or 2MPZ galaxies within 200 kpc of the source.
      and consistent (within 3-sigma) with the distance to the GW
object.
  
  Source 47:
  =============
    RA: 	 24.8943 ( = 01h 39m 34.63s) J2000
    Dec:	 +34.4368 ( = +34d 26' 12.5") J2000
    Error:	 +7.8 (arcsec, radius, 90% confidence).
    Peak Rate:	 1.5e-02 +/- 1.7e-02 ct/sec (0.3-10 keV)
    Peak Flux:	 6.4e-13 +/- 7.2e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 1.9e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    The source may be fading, at the 1.3-sigma level.
    There are 2 GWGC or 2MPZ galaxies within 200 kpc of the source.
      and consistent (within 3-sigma) with the distance to the GW
object.
  
  Source 48:
  =============
    RA: 	 25.1053 ( = 01h 40m 25.27s) J2000
    Dec:	 +34.3855 ( = +34d 23' 07.8") J2000
    Error:	 +6.9 (arcsec, radius, 90% confidence).
    Peak Rate:	 6.8e-03 +/- 5.3e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 2.9e-13 +/- 2.3e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 2.8e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    There are 2 GWGC or 2MPZ galaxies within 200 kpc of the source.
      and consistent (within 3-sigma) with the distance to the GW
object.
  
  Source 49:
  =============
    RA: 	 24.8491 ( = 01h 39m 23.78s) J2000
    Dec:	 +34.5412 ( = +34d 32' 28.3") J2000
    Error:	 +6.2 (arcsec, radius, 90% confidence).
    Peak Rate:	 3.5e-03 +/- 1.9e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 1.5e-13 +/- 8.2e-14 erg cm^-2 s^-1 (0.3-10 keV)
    1SXPS UL:	 1.4e-03 ct/sec, (0.3-10 keV)
       so the source is 1.1-sigma above the 1SXPS 3-sigma upper limit.
    RASS UL:	 3.4e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    There is 1 GWGC or 2MPZ galaxy within 200 kpc of the source.

      and consistent (within 3-sigma) with the distance to the GW
object.
    A SIMBAD object `LAMOST J013923.93+343234.0' is 5.9" away.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 50:
  =============
    RA: 	 25.0324 ( = 01h 40m 7.78s) J2000
    Dec:	 +34.6094 ( = +34d 36' 33.8") J2000
    Error:	 +7.1 (arcsec, radius, 90% confidence).
    Peak Rate:	 4.0e-03 +/- 4.6e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 1.7e-13 +/- 2.0e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 2.6e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    There are 2 GWGC or 2MPZ galaxies within 200 kpc of the source.
      and consistent (within 3-sigma) with the distance to the GW
object.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 51:
  =============
    RA: 	 25.1025 ( = 01h 40m 24.60s) J2000
    Dec:	 +34.5437 ( = +34d 32' 37.3") J2000
    Error:	 +7.5 (arcsec, radius, 90% confidence).
    Peak Rate:	 2.7e-03 +/- 2.2e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 1.2e-13 +/- 9.5e-14 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 1.8e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    There are 3 GWGC or 2MPZ galaxies within 200 kpc of the source.
      and consistent (within 3-sigma) with the distance to the GW
object.
  
  Source 52:
  =============
    RA: 	 24.9789 ( = 01h 39m 54.94s) J2000
    Dec:	 +34.6917 ( = +34d 41' 30.1") J2000
    Error:	 +7.9 (arcsec, radius, 90% confidence).
    Peak Rate:	 4.7e-03 +/- 2.9e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 2.0e-13 +/- 1.2e-13 erg cm^-2 s^-1 (0.3-10 keV)
    RASS UL:	 2.5e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    There is no evidence for fading.
    There are 2 GWGC or 2MPZ galaxies within 200 kpc of the source.
      and consistent (within 3-sigma) with the distance to the GW
object.
  
  Source 53:
  =============
    RA: 	 24.8754 ( = 01h 39m 30.10s) J2000
    Dec:	 +34.6003 ( = +34d 36' 01.1") J2000
    Error:	 +8.4 (arcsec, radius, 90% confidence).
    Peak Rate:	 2.1e-02 +/- 2.3e-02 ct/sec (0.3-10 keV)
    Peak Flux:	 8.9e-13 +/- 1.0e-12 erg cm^-2 s^-1 (0.3-10 keV)
    1SXPS UL:	 1.4e-02 ct/sec, (0.3-10 keV)
       so the source is not above the 1SXPS 3-sigma upper limit.
    RASS UL:	 2.1e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)

       so the source is not above the RASS 3-sigma upper limit.
    The source may be fading, at the 1.3-sigma level.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.


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. Therefore, we do not list details of the sources
here.

This circular is an official product of the Swift team.
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