[vsnet-grb-info 18092] LIGO/Virgo G211117/GW151226: serendipitous XMM-Newton slew observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19540
SUBJECT: LIGO/Virgo G211117/GW151226: serendipitous XMM-Newton slew observations
DATE:    16/06/16 19:31:59 GMT
FROM:    Eleonora Troja at GSFC  <eleonora.troja at nasa.gov>

A. M. Read (U. Leicester), A. Tiengo (IUSS Pavia), R. Salvaterra 
(INAF-IASF Milano), E. Troja (NASA/GSFC), R. D. Saxton (ESAC) report:

We analyzed the XMM-Newton slews made in the two weeks after the 
LIGO/Virgo G211117 / GW151226 event. Five slews intercept the BAYESTAR 
localization map in this period of time for a total coverage of about 26 
square degrees:

Obs ID     |    date    |  T-T_GW   |coverage of localization map
9294000002 | 2015-12-28 |   2.7 d   |  3 deg2
9294300002 | 2016-01-03 |   8.7 d   |  4 deg2
9294400002 | 2016-01-06 |  11.6 d   |  2 deg2
9294500002 | 2016-01-08 |  13.6 d   |  2 deg2
9294600002 | 2016-01-10 |  15.5 d   | 15 deg2

For each dataset (EPIC pn data with the Medium filter) we performed the 
source detection following the method described in Troja et al. 2016 
(ApJ, 822, L8).
Typical sensitivity limits of slew observations are ~6e-13 ergs cm-2 s-1 
in the 0.2-2 keV band and ~4e-12 ergs cm-2 s-1 in the 2-12 keV band. The 
list of the most significant 0.2-12 keV band detections (DET_ML>12) in 
each slew intersecting the GW151226 localization map with no counterpart 
within 30 arcsec in the ROSAT All Sky Survey (Boller et al. 2016, A&A 
588, A103) is reported below. The flux and counts are computed in the 
0.2-12 keV energy band.

----------
Revolution 2940, Observation ID 9294000002
RA (deg)    DEC (deg)  POS_ERR (")   CTS  CTS_ERR  DET_ML EXPOSURE (s) 
FLUX (ergs cm-1 s-1)
27.3262   -1.1849         4.1           6.2    2.6 20.1          
12.0               5.2e-12

----------
Revolution 2943, Observation ID 9294300002
RA (deg)    DEC (deg)  POS_ERR (")   CTS  CTS_ERR  DET_ML EXPOSURE (s) 
FLUX (ergs cm-1 s-1)
15.6690   -20.0254       3.3             6.6     2.8 18.7         
7.8                 8.5e-12
14.6309   -17.6256       4.7             4.8     2.4 12.9         
3.3                 1.4e-11

----------
Revolution 2944, Observation ID 9294400002
RA (deg)    DEC (deg)  POS_ERR (")   CTS  CTS_ERR  DET_ML EXPOSURE (s)  
FLUX (ergs cm-1 s-1)  Notes
186.5515   5.5650         5.1             5.0     2.4 14.8         
9.4                 5.3e-12     Detected also in Revolution 2945
186.7524   6.0297         3.5             4.8     2.3 17.9         
11.3               4.2e-12
186.2499   5.0154         4.5             4.7     2.3 13.7         
10.8               4.3e-12
185.0333   2.4117         4.2             7.8     3.0 20.0          
6.2                1.2e-11

----------
Revolution 2945, Observation ID 9294500002
RA (deg)    DEC (deg)  POS_ERR (")   CTS  CTS_ERR  DET_ML EXPOSURE (s)  
FLUX (ergs cm-1 s-1)   Notes
186.5545   5.5635        3.3               8.6     3.0 34.1        
8.8                 9.8e-12     Detected also in Revolution 2944
186.9961   6.5894        3.6               4.5     2.2 18.6        
13.4               3.3e-12
186.6783   5.9833        5.2               5.5     2.5 16.8        
12.0               4.5e-12
185.7506   3.7284        5.4               4.4     2.2 14.4        
10.3               4.3e-12

----------
Revolution 2946, Observation ID 92946 00002
RA (deg)     DEC (deg)  POS_ERR (")   CTS  CTS_ERR  DET_ML EXPOSURE 
(s)   FLUX (ergs cm-1 s-1)
187.2622    7.6581       4.5               8.2      3.2 12.4        
5.8                 1.4e-11
192.9292  -2.5083       4.9               5.7      2.6 15.4        
5.5                 1.0e-11
201.3687  -17.3449     8.7               4.9      2.3 12.5        
8.0                 6.2e-12