TITLE: GCN CIRCULAR NUMBER: 40711 SUBJECT: sb25061207: Swift-XRT observations DATE: 25/06/12 21:12:28 GMT FROM: Phil Evans at U of Leicester pae9@star.le.ac.uk
P.A. Evans (U. Leicester), J.A. Kennea (PSU), E. Ambrosi (INAF-IASFPA) , A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), R. Brivio (INAF-OAB), D.N. Burrows (PSU), S. Campana (INAF-OAB), M. Capalbi (INAF-OAR), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), V. D'Elia (SSDC & INAF-OAR), S. Dichiara (PSU), M. Ferro (INAF-OAB), A. Melandri (INAF-OAR), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M. Perri (SSDC & INAF-OAR), C. Salvaggio (INAF-OAB), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), M.A. Williams (PSU) report on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the SVOM/ECLAIRs-detected source sb25061207, collecting 2.6 ks of Photon Counting (PC) mode data between T0+8.8 ks and T0+20 ks after the trigger. We have detected 4 sources. These have been automatically classified as follows: * 0 likely counterparts * 0 candidate counterparts * 4 uncatalogued X-ray sources * 0 known X-ray sources
Uncatalogued X-ray sources --------------------------
Source 1 (SWIFT J131222.8+000431): ================================== RA (J2000.0): 198.0954 = 13h 12m 22.90s Dec (J2000.0): +0.0753 = +00d 04' 31.1" Error: 6.4 (arcsec, radius, 90% confidence). Detect flag: GOOD Distance: 7.2 arcmin from the SVOM/ECLAIRs position; 4.6 arcsec from SVOM/VT counterpart (GCN 40707). Mean rate: 0.0133 [+0.0031, -0.0028] ct s^-1 Mean flux: (6.0 [+1.4, -1.3])e-13 erg cm^-2 s^-1 Peak rate: 0.0147 +/- 0.0037 ct s^-1 Peak flux: (6.6 +/- 1.7)e-13 erg cm^-2 s^-1 ECF: 4.50e-11 erg cm^-2 ct^-1, assuming NH=2.24e+20 cm^-2, gamma=1.42; determined from a spectral fit. XMM UL: 2.7e-12 erg cm^-2 s^-1, (0.3-10 keV) so the source is 12.4-sigma above this 3-sigma upper limit. The source may be fading, at the 0.6-sigma level.
Source 2 (SWIFT J131136.2+000123): ================================== RA (J2000.0): 197.9010 = 13h 11m 36.24s Dec (J2000.0): +0.0233 = +00d 01' 23.9" Error: 5.9 (arcsec, radius, 90% confidence). Detect flag: GOOD Distance: 5.2 arcmin from the SVOM/ECLAIRs position. Mean rate: (7.2 +/- 2.1)e-3 ct s^-1 Mean flux: (7.4 +/- 2.1)e-13 erg cm^-2 s^-1 Peak rate: (7.2 +/- 2.1)e-3 ct s^-1 Peak flux: (7.4 +/- 2.1)e-13 erg cm^-2 s^-1 ECF: 1.03e-10 erg cm^-2 ct^-1, assuming NH=2.41e+21 cm^-2, gamma=0.47; determined from a spectral fit. XMM UL: 4.4e-12 erg cm^-2 s^-1, (0.3-10 keV) so the source is 17.2-sigma above this 3-sigma upper limit. There is no evidence for fading. A SIMBAD object `MGC 42939' is 5.7" away.
Source 3 (SWIFT J131139.2-000814): ================================== RA (J2000.0): 197.9134 = 13h 11m 39.22s Dec (J2000.0): -0.1375 = -00d 08' 15.0" Error: 7.3 (arcsec, radius, 90% confidence). Detect flag: GOOD Distance: 10.5 arcmin from the SVOM/ECLAIRs position. Mean rate: (6.3 [+2.4, -1.9])e-3 ct s^-1 Mean flux: (1.36 [+0.52, -0.42])e-18 erg cm^-2 s^-1 Peak rate: (6.3 [+2.4, -1.9])e-3 ct s^-1 Peak flux: (1.36 [+0.52, -0.42])e-18 erg cm^-2 s^-1 ECF: 2.14e-16 erg cm^-2 ct^-1, assuming NH=4.37e+21 cm^-2, gamma=96.83; determined from a spectral fit. XMM UL: 2.7e-12 erg cm^-2 s^-1, (0.3-10 keV) so the source is 5817530.8-sigma above this 3-sigma upper limit. There is no evidence for fading.
Source 4 (SWIFT J131140.3-000120): ================================== RA (J2000.0): 197.9181 = 13h 11m 40.34s Dec (J2000.0): -0.0225 = -00d 01' 21.0" Error: 6.1 (arcsec, radius, 90% confidence). Detect flag: REASONABLE Distance: 4.9 arcmin from the SVOM/ECLAIRs position. Mean rate: (2.6 [+1.5, -1.2])e-3 ct s^-1 Mean flux: (1.61 [+0.96, -0.73])e-13 erg cm^-2 s^-1 Peak rate: (2.6 [+1.5, -1.2])e-3 ct s^-1 Peak flux: (1.61 [+0.96, -0.73])e-13 erg cm^-2 s^-1 ECF: 6.23e-11 erg cm^-2 ct^-1, assuming NH=3.65e+22 cm^-2, gamma=2.45; determined from a spectral fit. XMM UL: 4.8e-12 erg cm^-2 s^-1, (0.3-10 keV) so the source is 55.2-sigma above this 3-sigma upper limit. There is no evidence for fading.
All fluxes are 0.3-10 keV, observed. 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-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/SVOM.
This circular is an official product of the Swift-XRT team.
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