J/MNRAS/412/1853 Unidentified X-ray sources in XMM Slew Survey (Starling+, 2011)
Swift follow-up of unidentified X-ray sources in the XMM-Newton Slew Survey.
Starling R.L.C., Evans P.A., Read A.M., Saxton R.D., Esquej P., Krimm H.,
O'Brien P.T., Osborne J.P., Mateos S., Warwick R., Wiersema K.
<Mon. Not. R. Astron. Soc., 412, 1853-1869 (2011)>
=2011MNRAS.412.1853S 2011MNRAS.412.1853S
ADC_Keywords: X-ray sources ; Photometry, UBVRI ; Photometry, infrared ;
Ultraviolet
Keywords: surveys - X-rays: general
Abstract:
We present deep Swift follow-up observations of a sample of 94
unidentified X-ray sources from the XMM-Newton Slew Survey. The
X-ray Telescope (XRT) on-board Swift detected 29 per cent of the
sample sources; the flux limits for undetected sources suggest the
bulk of the Slew Survey sources are drawn from one or more transient
populations. We report revised X-ray positions for the XRT-detected
sources, with typical uncertainties of 2.9 arcsec, reducing the number
of catalogued optical matches to just a single source in most cases.
We characterize the sources detected by Swift through their X-ray
spectra and variability and via Ultraviolet-Optical Telescope
photometry and using catalogued near-infrared, optical and radio
observations of potential counterparts. Six sources can be associated
with known objects and eight sources may be associated with
unidentified ROSAT sources within the 3σ error radii of our
revised X-ray positions.
Description:
We observed the 94 sources with all instruments on-board Swift
simultaneously: the wide field of view Burst Alert Telescope (BAT)
operating in the energy range 15-150keV, and the narrow-field
instruments - the X-Ray Telescope (XRT) and the Ultraviolet-Optical
Telescope (UVOT).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 109 97 Swift XRT observations of unidentified
XMM-Newton Slew Survey sources
table2.dat 70 27 Source positions and associated errors derived
from the XRT observations
table3.dat 148 13 Possible ROSAT associations, displaying agreement
within the 3σ positional uncertainties
table4.dat 92 27 Results of absorbed power-law fits to the X-ray
spectra of XRT detected sources
table6.dat 101 30 *UVOT photometry (observed magnitudes from a sum
of all images)
table7.dat 148 27 *Optical/nIR photometry of catalogue matches with
USNO-B1.0, YB6 USNO and 2MASS
table8.dat 105 28 Summary of proposed classifications for individual
sources, and/or any associated catalogued sources
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Note on table6.dat: where a single source lies inside XRT error circle of
XRT-detected objects, and best source position in degrees as measured
from all of the UVOT filters.
Note on table7.dat: where a single source lies within the XRT error circle.
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See also:
J/A+A/480/611 : XMM-Newton slew survey catalogue, XMMSL1 (Saxton+, 2008)
IX/28 : ROSAT HRI Pointed Observations (1RXH) (ROSAT Team, 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- --- [XMMSL1]
8- 23 A16 --- XMMSL1 XMMSL1 source name (JHHMMSS.s+DDMMSS)
25- 27 F3.1 ct/s FCR ?=- Slew count rate in full (0.2-12keV) band
29- 31 F3.1 ct/s e_FCR ?=- rms uncertainty on FCR
33- 35 F3.1 ct/s HCR ?=- Slew count rate in hard (2-12keV) band
37- 39 F3.1 ct/s e_HCR ?=- rms uncertainty on HCR
41- 43 F3.1 ct/s SCR ?=- Slew count rate in soft (0.2-2keV) band
45- 47 F3.1 ct/s e_SCR ?=- rms uncertainty on SCR
49- 56 I8 --- ObsID ? Swift obsID
58- 87 A30 --- Date Observation start, end
89- 93 F5.2 ks Texp ? Exposure time
95- 96 A2 --- l_XRT [≤] Limit flag on XRT
97-103 E7.3 ct/s XRT ? XRT count rate (1)
105-109 F5.3 ct/s e_XRT ? rms uncertainty on XRT
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Note (1): XRT count rates are PC mode 0.3-10keV with 1σ errors, or
3σ upper limits where no source was detected at ≥3σ
significance (in which case no error is given).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- XMMSL1 XMMSL1 source name (JHHMMSS.s+DDMMSS)
18- 26 F9.5 deg RAdeg XMM right ascension in decimal degrees (J2000)
28- 36 F9.5 deg DEdeg XMM right ascension in decimal degrees (J2000)
38- 40 I3 arcsec ePos1 Error on XMM position (radius, 90% containment)
42- 50 F9.5 deg RA2deg XRT right ascension in decimal degrees (J2000)
52- 60 F9.5 deg DE2deg XRT declination in decimal degrees (J2000)
62- 64 F3.1 arcsec ePos2 Error on XRT position (radius, 90% containment)
65 A1 --- n_ePos2 [*] Position not UVOT enhanced (1)
67- 70 F4.1 arcsec dPos Position difference
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Note (1): All XRT positions have been UVOT enhanced,
except where indicated with *.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- XMMSL1 XMMSL1 source name (JHHMMSS.s+DDMMSS)
18- 40 A23 --- ROSAT ROSAT name
41 A1 --- n_ROSAT [*] ROSAT represents a XMM Slew name
43- 45 I3 arcsec ePos3 ROSAT position error
47- 50 F4.1 arcsec ePos2 ? XRT position error
52- 55 F4.1 arcsec dPos Position difference
57-148 A92 --- Com Comments
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- XMMSL1 XMMSL1 source name (JHHMMSS.s+DDMMSS)
18- 21 F4.2 --- Gamma ? Power-law photon index, Γ
23- 26 F4.2 --- E_Gamma ? Error on Gamma (upper value)
28- 31 F4.2 --- e_Gamma ? Error on Gamma (lower value)
32 A1 --- n_Gamma [N] N for No acceptable fit
34- 37 F4.1 10+20cm-2 NH ? Hygrogen column density
39- 42 F4.1 10+20cm-2 E_NH ? Error on NH (upper value)
44- 47 F4.1 10+20cm-2 e_NH ? Error on NH (lower value)
48 A1 --- n_NH [U] U for unconstrained
50- 54 F5.2 10+20cm-2 NHG Hygrogen Galactic column density (2)
56- 59 F4.2 fW/m2 OFlux Observed flux in 0.3-10keV band (3)
61- 64 F4.2 fW/m2 E_OFlux ? Error on OFlux (upper value) (3)
66- 69 F4.2 fW/m2 e_OFlux ? Error on OFlux (lower value) (3)
70 A1 --- n_OFlux [a] Note on OFlux (4)
72- 76 F5.2 fW/m2 UFlux ? Unabsorbed flux in 0.3-10keV band (3)
79- 84 F6.2 --- C-stat ? C-statistic
86- 88 I3 --- DOF ? Degree of freedom
90- 92 I3 ct Nct Total number of source counts
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Note (2): NHG is a weighted average at the XRT position (Kalberla et al.
2005, Cat. VIII/76).
Note (3): expressed in 10-12erg/s/cm2 = 10-15W/m2
Note (4): a indicates that the flux is taken from an unconstrained absorbed
power-law fit and so is approximate. This fit had a power-law photon
index of Γ∼9.3 and absorption NH∼1022cm-2; blackbody and MEKAL
fits also resulted in no acceptable solutions.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- XMMSL1 XMMSL1 source name (JHHMMSS.s+DDMMSS)
18- 21 F4.2 ks Texp Exposure time
23- 26 F4.2 mag AB ? Galactic extinction expected in B band (1)
28- 33 F6.3 mag bmag ?=- UVOT B (λ4392Å) magnitude
35- 39 F5.3 mag e_bmag ? rms uncertainty on bmag
41- 45 F5.2 mag uvw1mag ?=- UVOT UVW1 (λ2600Å) magnitude
47- 50 F4.2 mag e_uvw1mag ? rms uncertainty on uvw1mag
52- 56 F5.2 mag uvm2mag ?=- UVOT UVM2 (λ2246Å) magnitude
58- 61 F4.2 mag e_uvm2mag ? rms uncertainty on uvm2mag
63- 67 F5.2 mag uvw2mag ?=- UVOT UVW2 (λ1928Å) magnitude
69- 72 F4.2 mag e_uvw2mag ? rms uncertainty on uvw2mag
74- 82 F9.5 deg RAdeg Right ascension in decimal degrees (J2000)
84- 92 F9.5 deg DEdeg Declination in decimal degrees (J2000)
94- 97 F4.2 arcsec ePos Error in position (90% confidence level)
99-101 F3.1 arcsec Dist Distance from XRT
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Note (1): AB at λ 4400Å, Schlegel et al., 1998ApJ...500..525S 1998ApJ...500..525S).
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- XMMSL1 XMMSL1 source name (JHHMMSS.s+DDMMSS)
18- 20 F3.1 arcsec Dist ? Distance from XRT position (5)
22- 26 F5.2 mag Bmag ? USNO-B magnitude (6)
28- 32 F5.2 mag Vmag ? NOMAD V magnitude (6)
33 A1 --- n_Vmag [a] a when Vmag from LSPM catalogue,
see Appendix A2
35- 39 F5.2 mag Rmag ? USNO R magnitude (6)
41- 45 F5.2 mag Imag ? I magnitude (6)
47- 51 F5.2 mag Jmag ? USNO 2MASS J magnitude
53- 56 F4.2 mag e_Jmag ? rms uncertainty on Jmag
58- 62 F5.2 mag Hmag ? 2MASS H magnitude
64- 67 F4.2 mag e_Hmag ? rms uncertainty on Hmag
69- 73 F5.2 mag Kmag ? 2MASS K magnitude
75- 78 F4.2 mag e_Kmag ? rms uncertainty on Kmag
80 A1 --- PM? [N] Proper motion ?
82- 84 I3 mas/yr pmRA ? Proper motion along RA (7)
86- 87 I2 mas/yr e_pmRA ? rms uncertainty on pmRA
89- 92 I4 mas/yr pmDE ? Proper motion along DE (7)
94- 95 I2 mas/yr e_pmDE ? rms uncertainty on pmDE
97-101 F5.2 [-] logFX/FR ? X-ray to radio flux ratio
103-148 A46 --- Com Comments (catalogued name (VizieR) and ID)
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Note (5): Distances from the XRT position are taken from the 2MASS source
if available, otherwise from USNO-B1.0.
Note (6): USNO-B1.0 (BRI, if not available then we use USNO-A2.0), YB6 USNO
unpublished catalogue reported in NOMAD (V).
Note (7): Proper motions (PM) are quoted from the NOMAD data base.
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- --- [XMMSL1]
8- 23 A16 --- XMMSL1 XMMSL1 source name (JHHMMSS.s+DDMMSS)
25- 59 A35 --- Ident Proposed identification
61-105 A45 ---- ANames Associated catalogued sources
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 02-Nov-2011