GCN Circular 18748
Subject
LIGO/Virgo G211117: Further Swift-XRT sources
Date
2015-12-29T10:02:14Z (8 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans (U. Leicester), J.A. Kennea (PSU), Scott Barthelmy
(NASA/GSFC), Dave Burrows (PSU), Sergio Campana (INAF-OAB), Brad Cenko
(NASA/GSFC), Neil Gehrels (NASA/GSFC), Paolo Giommi (ASI), Frank
Marshall (NASA/GSFC), John Nousek (PSU), Paul O'Brien (U. Leicester),
Julian Osborne (U. Leicester), David Palmer (LANL), Matteo Perri
(ASDC), Judy Racusin (NASA/GSFC), Mike Siegel (PSU), Gianpiero
Tagliaferri (INAF-OAB) report on behalf of the Swift team:
Swift has performed a series of 75 observations of galaxies (from the
GWGC catalogue) within the aLIGO error region for the aLIGO trigger
G211117, using the 'bayestar' GW localisation map. The observations
currently span from 140 ks to 217 ks after the aLIGO trigger, and cover
8.4 sq degrees on the sky (corrected for overlaps).
Since the last Swift GCN, we have detected a 9 X-ray sources, these are
either new detections, or have been given a higher 'rank' than in the
last circular. 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
* 0 sources of rank 2
* 4 sources of rank 3
* 5 sources of rank 4
We assumed a power-law spectrum with NH=3e20 cm^2, and Gamma=1.7
In addition to these sources a number of objects were detected and
reported in COUNTERPART notices, which are in fact artefacts around
extended sources, and are not point source detections. These spurious
sources are not reported below.
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 13:
=============
RA: 187.6968 ( = 12h 30m 47.23s) J2000
Dec: +12.3389 ( = +12d 20' 20.0") J2000
Error: +6.4 (radius, 90% confidence).
Peak Rate: 1.5e-01 +/- 5.4e-02 ct/sec (0.3-10 keV)
Peak Flux: 6.3e-12 +/- 2.3e-12 erg cm^-2 s^-1 (0.3-10 keV)
RASS UL: 2.5e+00 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)
So the source is not significantly above the RASS 3-sigma limit
There is no evidence for fading
There is 1 GWGC galaxy within 200 kpc of the source.
Source 24:
=============
RA: 188.0297 ( = 12h 32m 7.13s) J2000
Dec: +11.8560 ( = +11d 51' 21.6") J2000
Error: +7.5 (radius, 90% confidence).
Peak Rate: 1.6e-02 +/- 6.1e-03 ct/sec (0.3-10 keV)
Peak Flux: 6.7e-13 +/- 2.6e-13 erg cm^-2 s^-1 (0.3-10 keV)
RASS UL: 5.5e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)
So the source is not significantly above the RASS 3-sigma limit
There is no evidence for fading
NOTE: this source is not within 200 kpc of a GWGC galaxy.
Source 27:
=============
RA: 187.9278 ( = 12h 31m 42.67s) J2000
Dec: +12.3292 ( = +12d 19' 45.1") J2000
Error: +11.7 (radius, 90% confidence).
Peak Rate: 1.8e-02 +/- 1.0e-02 ct/sec (0.3-10 keV)
Peak Flux: 7.7e-13 +/- 4.4e-13 erg cm^-2 s^-1 (0.3-10 keV)
RASS UL: 2.6e-01 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)
So the source is not significantly above the RASS 3-sigma limit
There is no evidence for fading
NOTE: this source is not within 200 kpc of a GWGC galaxy.
Source 44:
=============
RA: 187.8733 ( = 12h 31m 29.59s) J2000
Dec: +11.8772 ( = +11d 52' 37.9") J2000
Error: +6.7 (radius, 90% confidence).
Peak Rate: 1.4e-02 +/- 6.2e-03 ct/sec (0.3-10 keV)
Peak Flux: 5.9e-13 +/- 2.6e-13 erg cm^-2 s^-1 (0.3-10 keV)
RASS UL: 8.8e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)
So the source is not significantly above the RASS 3-sigma limit
There is no evidence for fading
NOTE: this source is not within 200 kpc of a GWGC galaxy.
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 6:
=============
RA: 207.1852 ( = 13h 48m 44.45s) J2000
Dec: -30.4960 ( = -30d 29' 45.6") J2000
Error: +6.0 (radius, 90% confidence).
Peak Rate: 5.1e-02 +/- 1.2e-02 ct/sec (0.3-10 keV)
Peak Flux: 2.2e-12 +/- 5.2e-13 erg cm^-2 s^-1 (0.3-10 keV)
Cat Source: XMMSL1 J134844.6-302948 in the XMM-NEWTON/XMMSLEWCLN
catalogue
Separation: 2.7" from the XRT source
Cat Rate: 1.4e+00 +/- 3.7e-01 ct/sec (0.3-10 keV)
Cat Flux: 1.5e-11 +/- 3.9e-12 erg cm^-2 s^-1 (0.3-10 keV)
So the source is not significantly above the catalogued flux
The source may be fading, at the 0.3-sigma level.
NOTE: this source is not within 200 kpc of a GWGC galaxy.
A SIMBAD object `2XMM J134844.7-302943' is 3.7" away
There is 1 2MASS object within the source's 3-sigma error radius
Source 7:
=============
RA: 207.2700 ( = 13h 49m 4.80s) J2000
Dec: -30.2955 ( = -30d 17' 43.8") J2000
Error: +7.3 (radius, 90% confidence).
Peak Rate: 4.7e-02 +/- 1.2e-02 ct/sec (0.3-10 keV)
Peak Flux: 2.0e-12 +/- 5.3e-13 erg cm^-2 s^-1 (0.3-10 keV)
Cat Source: XMMSL1 J134904.4-301745 in the XMM-NEWTON/XMMSLEWCLN
catalogue
Separation: 3.6" from the XRT source
Cat Rate: 1.6e+00 +/- 4.9e-01 ct/sec (0.3-10 keV)
Cat Flux: 1.7e-11 +/- 5.2e-12 erg cm^-2 s^-1 (0.3-10 keV)
So the source is not significantly above the catalogued flux
There is no evidence for fading
There is 1 GWGC galaxy within 200 kpc of the source.
A SIMBAD object `[RP98d] P6' is 6.3" away
There is 1 2MASS object within the source's 3-sigma error radius
Source 16:
=============
RA: 187.6792 ( = 12h 30m 43.01s) J2000
Dec: +12.3882 ( = +12d 23' 17.5") J2000
Error: +5.9 (radius, 90% confidence).
Peak Rate: 4.3e+00 +/- 1.2e+00 ct/sec (0.3-10 keV)
Peak Flux: 1.8e-10 +/- 5.2e-11 erg cm^-2 s^-1 (0.3-10 keV)
Cat Source: 2RXP J123044.7+122331 in the ROSAT/ROSPSPC catalogue
Separation: 28.9" from the XRT source
Cat Rate: 0.0e+00 +/- 0.0e+00 ct/sec (0.3-10 keV)
Cat Flux: 0.0e+00 +/- 0.0e+00 erg cm^-2 s^-1 (0.3-10 keV)
So the source is not significantly above the catalogued flux
The source may be fading, at the 0.7-sigma level.
There is 1 GWGC galaxy within 200 kpc of the source.
A SIMBAD object `[SFH81] 1157' is 7.9" away
Source 23:
=============
RA: 187.8039 ( = 12h 31m 12.94s) J2000
Dec: +12.0537 ( = +12d 03' 13.3") J2000
Error: +6.5 (radius, 90% confidence).
Peak Rate: 7.0e-02 +/- 2.5e-02 ct/sec (0.3-10 keV)
Peak Flux: 3.0e-12 +/- 1.1e-12 erg cm^-2 s^-1 (0.3-10 keV)
Cat Source: 3XMM J123113.1+120307 in the XMM-NEWTON/XMMSSC
catalogue
Separation: 6.8" from the XRT source
Cat Rate: 5.4e-01 +/- 5.9e-03 ct/sec (0.3-10 keV)
Cat Flux: 5.7e-12 +/- 6.2e-14 erg cm^-2 s^-1 (0.3-10 keV)
So the source is not significantly above the catalogued flux
There is no evidence for fading
NOTE: this source is not within 200 kpc of a GWGC galaxy.
A SIMBAD object `2MASX J12311311+1203075' is 6.7" away
There is 1 2MASS object within the source's 3-sigma error radius
Source 32:
=============
RA: 187.7473 ( = 12h 30m 59.35s) J2000
Dec: +12.1925 ( = +12d 11' 33.0") J2000
Error: +5.6 (radius, 90% confidence).
Peak Rate: -1.0e+00 +/- -1.0e+00 ct/sec (0.3-10 keV)
Peak Flux: -4.3e-11 +/- -4.3e-11 erg cm^-2 s^-1 (0.3-10 keV)
Cat Source: 3XMM J123059.4+121131 in the XMM-NEWTON/XMMSSC
catalogue
Separation: 1.8" from the XRT source
Cat Rate: 7.5e-01 +/- 9.4e-03 ct/sec (0.3-10 keV)
Cat Flux: 7.9e-12 +/- 9.9e-14 erg cm^-2 s^-1 (0.3-10 keV)
So the source is not significantly above the catalogued flux
There is no evidence for fading
NOTE: this source is not within 200 kpc of a GWGC galaxy.
A SIMBAD object `2XMM J123059.4+121131' is 2.7" away
This circular is an official product of the Swift team.