IX/71 XMM-Newton slew survey Source Catalogue, version 3.0 (XMM-SSC, 2025)
The XMM-Newton slew survey Source Catalogue, version 3.0
XMM-SSC
<XMM-SSC, Leicester, UK (2025)>
=2025yCat.9071....0X 2025yCat.9071....0X
ADC_Keywords: X-ray sources; Surveys
Mission_Name: XMM
Keywords: catalogs - astronomical data bases - surveys - X-rays: general
Description:
The XMMSL3 catalogue is the third version of the XMM-Newton slew
catalogue. It contains detections drawn from 3120 XMM-Newton pn slew
observations, covering an energy interval from 0.2 keV to 12keV.
These observations were made between 2000 August 26 and 2023 August
11. All slew observations are public.
Should you use the catalogue for your research and publish the
results, please use the acknowledgement below. The current paper to
cite describing the catalogue is (Saxton et al., 2008A&A...480..611S 2008A&A...480..611S).
The median flux in the total photon energy band (0.2-12keV) of the
catalogue detections is ∼2.7x10-12erg/cm2/s; in the soft
energy band (0.2-2keV) the median flux is ∼1.1x10-12erg/cm2/s,
and in the hard band (2-12keV) it is ∼9.0x10-12erg/cm2/s.
It is possible that there are more counts in the soft or the hard band
than in the full band. This is because detections are carried out in
each band and then combined using a match radius of 30 arcseconds to
identify sources detected in more than one band. The match radius is
approximately 4 sigma and is reasonable for point sources because of
the scarcity of sources (1 detection per square degree on average) at
the flux levels probed by the slew survey. Therefore the extraction
region maybe placed at slightly different positions, resulting in this
incoherance. This also explains why band 8 (full band) may have many
more counts than the sum of the soft and the hard band.
The catalogue is manually screened to identify possibly spurious
detections. We recommend to filter the catalogue on the VAL_FLAG
column, keeping only those detections with the CLEAN_SAMPLE
qualification to obtain a clean catalogue.
The XMMSL3 catalogue has a new major version, as there are twice as
many sources as in XMMSL2 and the recommended method for producing a
cleaned catalogue has been modified with respect to the previous
version, XMMSL2, notably through filtering the catalogue on the
VAL_FLAG column, keeping only those detections with the CLEAN_SAMPLE
qualification. However, in other respects, it is an incremental
version, retaining all detections in XMMSL2 and adding a further 8.5
years of data.
Since XMMSL2, there have been a number of revisions made to the source
detection tasks and notably to the SAS task emldetect. All detections
are tested for their potential spatial extent during the fitting
process. The instrumental point-spread function (PSF) is convolved
with a β extent model, fitted to the detection, and the extent
likelihood is calculated as described by Section 4.4.4 of Watson et
al. 2009A&A...493..339W 2009A&A...493..339W). A detection is classified as extended if its
core radius (of the β-model of the PSF), rc>6arcsec and if the
extended model improved the likelihood with respect to the point
source fit such that it exceeded a threshold of Lext,min=4. In the
XMMSL2 version, when a detection was identified as pointlike, the
extent maximum likelihood (EXTMLB6, EXTMLB7 or EXTMLB8) was set
to -999. Since version 7.5.2 of emldetect, a negative maximum
likelihood is attributed to point-like detections. Lext,min>-=4
indicates that a source is probably extended, whilst negative values
indicate a clear preference of the point-like over the extended fit. A
minimum likelihood difference of four has been chosen to mark a
detection as extended. This threshold makes sure that the improvement
of the extended over the point-like fit is not only due to statistical
fluctuations but from a more precise description of the source
profile. Where no detection in a particular band has been made, there
is no extension maximum likelihood provided for that band. Therefore,
the extension maximum likelihood column is composed of positive and
negative values, as well as the value -999 and nulls.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
xmmsl3c.dat 1365 140735 XMM-Newton slew survey Source Catalogue: XMMSL3
"clean version" (Release 1.0, 18th Feb 2025)
xmmsl3c.fits 2880 40724 Clean XMMSL3 catalog in fits
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See also:
IX/69 : XMM-Newton Serendipitous Source Catalogue 4XMM-DR13 (Webb+, 2023)
II/340 : XMM-OM Serendipitous Source Survey Catalogue XMM-SUSS2.1 (Page+ 2016)
http://xmmssc.irap.omp.eu/Catalogue/XMMSL3/XMMSL3.html : XMMSL3 Home Page
Byte-by-byte Description of file: xmmsl3c.dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- XMMSL3 Official name for sources detected in
the XMM-Newton slew survey
(UNIQUE_SRCNAME) (1)
25- 34 A10 --- ObsId Observation number (OBSID) (2)
36- 39 I4 --- SNum Number which uniquely identifies each
detection in an observation (SOURCENUM)
41- 55 F15.11 deg RAdeg Right ascension (J2000) (RA) (3)
57- 71 F15.11 deg DEdeg Declination (J2000) (DEC) (3)
73- 83 F11.7 arcsec ePos Statistical error on the source position
(RADEC_ERR) (4)
85- 99 F15.11 deg GLON Galactic longitude (LII)
101- 115 F15.11 deg GLAT Galactic latitude (BII)
117- 125 F9.6 --- HR1 ?=- Hardness ratio (HR1) (5)
127- 134 F8.6 --- e_HR1 ?=- rms uncertainty on HR1 (HR1_ERR) (6)
136- 154 A19 --- DateS Start time of the slew containing
this source (DATE_OBS)
156- 174 A19 --- DateE End time of the slew containing
this source (DATE_END)
176- 187 E12.6 ct SctsB8 ?=- Number of background subtracted
counts, in the total energy band
(0.2-12keV) (SCTS_B8) (7)
189- 197 F9.5 ct e_SctsB8 ?=- Statistical 1 sigma error on SctsB8
(SCTSB8ERR)
199- 210 E12.6 ct SctsB7 ?=- Number of background subtracted
counts, in the hard energy band
(2-12keV), corrected for the PSF
(SCTS_B7)
212- 219 F8.5 ct e_SctsB7 ?=- Statistical 1 sigma error on SctsB7
(SCTSB7ERR)
221- 232 E12.6 ct SctsB6 ?=- Number of background subtracted
counts, in the soft energy band
(0.2-2keV), corrected for the PSF
(SCTS_B6)
234- 242 F9.5 ct e_SctsB6 ?=- Statistical 1 sigma error on SctsB6
(SCTSB6ERR)
244- 255 E12.6 pix XimaB8 ?=- X position in the total band image in
image pixels (XIMAB8)
257- 268 E12.6 pix YimaB8 ?=- Y position in the total band image in
image pixels (YIMAB8)
270- 281 E12.6 pix XimaB7 ?=- X position in the hard band image in
image pixels(XIMAB7)
283- 294 E12.6 pix YimaB7 ?=- Y position in the hard band image in
image pixels(YIMAB7)
296- 307 E12.6 pix XimaB6 ?=- X position in the soft band image in
image pixels(XIMAB6)
309- 320 E12.6 pix YimaB6 ?=- Y position in the soft band image in
image pixels(YIMAB6)
322- 330 F9.6 pix ExtB8 ?=- Spatial extension of the source in
the total energy band (EXT_B8) (7)
332- 340 F9.6 pix e_ExtB8 ?=- Statistical one sigma error on ExtB8
(EXTB8ERR)
342- 350 F9.6 pix ExtB7 ?=- Spatial extension of the source in
the hard energy band (EXT_B7) (7)
352- 360 F9.6 pix e_ExtB7 ?=- Statistical one sigma error on ExtB7
(EXTB7ERR)
362- 370 F9.6 pix ExtB6 ?=- Spatial extension of the source in
the soft energy band (EXT_B6) (7)
372- 380 F9.6 pix e_ExtB6 ?=- Statistical one sigma error on ExtB6
(EXTB6ERR)
382- 393 F12.6 --- DetMLB8 ?=- Detection likelihood in the total
(0.2-12keV) energy band (DETMLB8)
395- 406 F12.6 --- DetMLB7 ?=- Detection likelihood in the hard
(2-12keV) energy band (DETMLB7)
408- 419 F12.6 --- DetMLB6 ?=- Detection likelihood in the soft
(0.2-2keV) energy band (DETMLB6)
421- 432 F12.6 --- ExtMLB8 ?=- Likelihood of the source being
extended in the total band (EXTMLB8)
434- 445 F12.6 --- ExtMLB7 ?=- Likelihood of the source being
extended in the hard band (EXTMLB7)
447- 458 F12.6 --- ExtMLB6 ?=- Likelihood of the source being
extended in the soft band (EXTMLB6)
460- 467 F8.6 ct/pix BgMapB8 ?=- Background value for the total band
(BGMAPB8)
469- 476 F8.6 ct/pix BgMapB7 ?=- Background value for the hard band
(BGMAPB7)
478- 485 F8.6 ct/pix BgMapB6 ?=- Background value for the soft band
(BGMAPB6)
487- 496 F10.6 s ExpMapB8 ?=- Effective on-axis exposure time in
the total energy band (EXPMAPB8)
498- 507 F10.6 s ExpMapB7 ?=- Effective on-axis exposure time in
the hard energy band (EXPMAPB7)
509- 518 F10.6 s ExpMapB6 ?=- Effective on-axis exposure time in
the soft energy band (EXPMAPB6)
520- 531 F12.6 10-15W/m2 FluxB8 ?=- Flux in the total energy (0.2-12keV)
band (FLUX_B8)
533- 544 F12.6 10-15W/m2 e_FluxB8 ?=- Error in FluxB8 (FLUXB8ERR)
546- 557 F12.6 10-15W/m2 FluxB7 ?=- Flux in the total energy (2-12keV)
band (FLUX_B7)
559- 570 F12.6 10-15W/m2 e_FluxB7 ?=- Error in FluxB7 (FLUXB7ERR)
572- 582 F11.6 10-15W/m2 FluxB6 ?=- Flux in the total energy (0.2-2keV)
band (FLUX_B6)
584- 593 F10.6 10-15W/m2 e_FluxB6 ?=- Error in FluxB6 (FLUXB6ERR)
595- 605 F11.6 ct/s RateB8 ?=- Total band count rate (RATE_B8)
607- 616 F10.6 ct/s e_RateB8 ?=- Error in RateB8 (RATEB8ERR)
618- 628 F11.6 ct/s RateB7 ?=- Hard band count rate (RATE_B7)
630- 639 F10.6 ct/s e_RateB7 ?=- Error in RateB7 (RATEB7ERR)
641- 651 F11.6 ct/s RateB6 ?=- Soft band count rate (RATE_B6)
653- 662 F10.6 ct/s e_RateB6 ?=- Error in RateB6 (RATEB6ERR)
664- 678 F15.11 deg RAdegB8 ?=- Total band right ascension (J2000)
(RA_B8)
680- 694 F15.11 deg DEdegB8 ?=- Total band declination (J2000)
(DEC_B8)
696- 706 F11.7 deg ePosB8 ?=- Statistical error on total band
position (RADECB8ERR)
708- 722 F15.11 deg GLONB8 ?=- Total band galactic longitude
(LII_B8)
724- 738 F15.11 deg GLATB8 ?=- Total band galactic latitude (BII_B8)
740- 754 F15.11 deg RAdegB7 ?=- Hard band right ascension (J2000)
(RA_B7)
756- 770 F15.11 deg DEdegB7 ?=- Hard band declination (J2000)
(DEC_B7)
772- 782 F11.7 deg ePosB7 ?=- Statistical error on hard band
position (RADECB7ERR)
784- 798 F15.11 deg GLONB7 ?=- Hard band galactic longitude (LII_B7)
800- 814 F15.11 deg GLATB7 ?=- Hard band galactic latitude (BII_B7)
816- 830 F15.11 deg RAdegB6 ?=- Soft band right ascension (J2000)
(RA_B6)
832- 846 F15.11 deg DEdegB6 ?=- Soft band declination (J2000)
(DEC_B6)
848- 858 F11.7 deg ePosB6 ?=- Statistical error on soft band
position (RADECB6ERR)
860- 874 F15.11 deg GLONB6 ?=- Soft band galactic longitude (LII_B6)
876- 890 F15.11 deg GLATB6 ?=- Soft band galactic latitude (BII_B6)
892- 903 A12 --- Flag [CLEAN_SAMPLE] Flag for source included
in the clean subset (VAL_FLAG) (8)
905- 941 A37 --- SnameB8 Source name defined in the total band
list (SRCNAME_B8) (9)
943- 979 A37 --- SnameB7 Source name defined in the hard band list
(SRCNAME_B7) (9)
981-1017 A37 --- SnameB6 Source name defined in the soft band list
(SRCNAME_B6) (9)
1019-1049 A31 --- XInameB8 Name of the image containing the total
band detection (XIMNAME_B8)
1051-1081 A31 --- XInameB7 Name of the image containing the hard
band detection (XIMNAME_B7)
1083-1113 A31 --- XInameB6 Name of the image containing the soft
band detection (XIMNAME_B6)
1115 I1 --- Inext [0/1] Extended source flag
(VER_INEXT) (10)
1117 I1 --- Halo [0/1] Halo flag (VER_HALO) (11)
1119 I1 --- HIbgnd [0/1] Bright region flag
(VER_HIBGND) (12)
1121 I1 --- Nredg [0] Not used in XMMSL2 (VER_NREDG)
1123 I1 --- Psusp [0/1] Inaccurate position flag
(VER_PSUSP) (13)
1125 I1 --- False [0/1] Catch-all for problems not included
in the other flags (VER_FALSE) (14)
1127-1164 A38 --- Com Suspect attitude reconstruction in RAF
(FLAG_COMMENT) (15)
1166-1203 A38 --- Ident Cross-correlations of the positions of
the slew sources (IDENT) (16)
1205-1225 A21 --- AltID Alternatif identifier (ALTIDENT)
1227-1242 A16 --- 1RXS Name of the closest Rosat All Sky Survey
(RASS) source (RASSNAME) (17)
1244-1263 A20 --- Type Source type (ID_CATEGORY) (18)
1265-1272 A8 --- r_Type Reference for Type (ID_RESOURCE) (19)
1274-1283 F10.6 arcsec DistC ?=- Distance between the best match
candidate and the slew survey source
(ID_DIST)
1285-1290 F6.3 arcsec DistR ?=- Distance from the best match ROSAT
source and the slew source (RASS_DIST)
1292-1294 A3 --- ModeID Observing mode of the EPIC-pn camera
(MODE_ID) (20)
1296-1300 F5.1 ct/s ImBGRate Peak background count rate in the image
from which the source was extracted
(IMAGEBGRATE) (21)
1302-1311 F10.4 d MJDStart Start time of the subimage where the
source is located in modified Julian
date (MJD_START)
1313-1322 F10.4 d MJDStop End time of the subimage where the source
is located in modified Julian date
(MJD_STOP)
1324 I1 --- OPTLOAD [0/1] Warning flag indicating that the
source may suffer from optical loading
(VER_OPTLOAD)
1326-1329 I4 --- FiltCt ?=- Number of counts found within a
1 arcminute radius about the source
position after standard filtering is
applied (FILT_CNTS)
1331-1334 I4 --- UnfiltCt ?=- Number of counts found within a
1 arcminute radius about the source
position with no filtering applied
(UNFILT_CNTS)
1336-1358 A23 --- USXMMSL1 Name of the same source in the previous
XMMSL1 catalogue if existing (US_XMMSL1)
1360-1365 I6 --- USExtras ?=- Corresponding SRCID value within the
EXTraS LTV catalogue (US_EXTRAS) (22)
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Note (1): This is the official name for sources detected in the XMM-Newton slew
survey. It starts with the prefix, XMMSL3 (evolving from XMMSL1 and XMMSL2
the IAU registered designator), and then encodes the J2000 sky position, e.g.
XMMSL3 J010537.6+364858. The name is assigned in two passes. When the three
independent energy band source lists are combined to form one catalogue the
source name is set using the position in the band where the DET_ML likelihood
is the highest. A second pass is then performed such that sources which have
been observed in more than one slew are given the same name. Again, priority
is given depending on the detection likelihood. Note that the combination of
UNIQUE_SRCNAME and observation number (OBSID) is unique. Detections are deemed
to be from the same source if their centres lie within 30 arcseconds of each
other. Note that the statistical position error (RADEC_ERR) calculated by the
source search software is not used in this calculation. This is because the
systematic error on the slew attitude reconstruction dominates the error
budget in many cases. Given the scarcity of slew sources on the sky, 30" was
found to be a reasonably robust match radius for point sources. It is not so
good for extended sources and the catalogue may contain multiple detections of
the same extended source with different names.
Note (2): This is the observation number assigned to the slew by the satellite
scheduling system. Slew observations always begin with a 9 to distinguish
them from pointed observations, followed by a 4 digit satellite orbit number
and a 5 digit slew designator, e.g. 9031400004, refers to the second slew of
revolution 314.
Note (3): In the event of a detection in more than one energy band, the
coordinates are taken from the band with the highest detection likelihood.
Note (4): Statistical error on the source position as returned by the source
detection software.
Note (5): The hardness ratio, defined as
HR1 = (rateb7-rateb6)/(rateb7+rateb6)
where rate_b7 is the hard band count rate and rate_b6 is the soft band count
rate. This has been calculated for the 1936 sources which have a positive
detection in both bands.
Note (6): Error on the hardness ratio calculated as:
sqrt(rateb7err*rateb7err + rateb6err*rateb6err) /(rateb7+rateb6)
where rateb7err and rateb6err are the errors on the hard and soft band
count rates respectively.
Note (7): This measures the deviation from a point source of the spatial
distribution of the source counts. It is defined as the sigma of a Gaussian
which would need to be convolved with the point spread function (PSF) to
produce the observed counts distribution. The software (emldetect) fits
sources out to a maximum extent of 20 pixels.
Units: 4.1"x4.1" image pixels
Note (8): A text string which is set to 'CLEAN_SAMPLE' if this source is
included in the clean subset.
Note (9): The format is 'xs' followed by the revolution number, the observation
ID and the source position, e.g. xs0841908410000212:57:07.5+01:50:42
Note (10): If set true (1), this flag notes that a detection has been found with
in an extended source and is probably false. This flag is used to ensure that
only one source is quoted for the large supernova remnants.
Note (11): If set true (1), this flag indicates that a detection lies within the
point spread function, or halo, of a very bright source and is probably
spurious.
Note (12): If set true (1), this flag indicates that the source lies within a
bright region, caused by high background, and is probably spurious.
Note (13): This flag indicates that the quoted position of the source is likely
to be inaccurate. In a few slews the attitude reconstruction is poor and in
these cases the actual position of the source is difficult to determine and
can be wrong by an arcminute.
Note (14): This is a catch-all for problems not included in the other flags. In
the catalogue 99 detections have this flag set true. Reasons include: the
exposure time has been calculated as zero, a detection due to a very bright
source, e.g. SCO X-1, out of the field of view, a possible cosmic ray or a
very bad attitude reconstruction.
Note (15): A comment which explains why a particular source flag has been set
to true
Note (16): Cross-correlations of the positions of the slew sources with
astronomical databases and catalogues have been performed (see section on
IDs). This column gives the catalogue name of the best match.
Note (17): Voges et al. (1999, Cat. IX/10) and Voges et al. (2000, Cat. IX/29).
Note (18): The source type as returned by SIMBAD, NED and the other resources
used in the cross-matching process. This is directly taken from the catalogue
in question and no attempt has been made to rationalise the values.
Note (19): The astronomical database or catalogue from which the best match has
been selected. e.g. SIMBAD, NED, etc.
Note (20): Observing mode of the EPIC-pn camera as follows:
FF= Full frame mode
eFF = extended full frame mode
LW = large window mode
Note (21): Peak background count rate in the image from which the source was
extracted. This is measured as the count rate, over the whole image, for
events with energy >10keV (PI>10000). It is quoted to a resolution of 0.1ct/s
and is used to determine the overall background environment in which a source
was detected. This value is used in the creation of a clean subsample of the
catalogue (see top level description). Generally, the higher this value, the
greater the probability that the source is spurious. This is especially true
if the detection likelihood of the source is less than 15.5. The value has
been tabulated for images with a background rate greater than 2ct/s. For
quieter images the value has been artifically set to 1.9 ct/s.
Note (22): This release of XMMSL2 makes use of work carried out within the
framework of the EXTraS project. XMMSL2 is closely linked to the long-term
variability (LTV) catalogue within EXTraS, and this US_EXTRAS column provides
the corresponding SRCID value within the EXTraS LTV catalogue.
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History:
copied at http://xmmssc.irap.omp.eu/Catalogue/XMMSL3/XMMSL3.html
(End) Patricia Vannier [CDS] 12-Sep-2025