IX/12 The WGACAT version of ROSAT sources (White+ 1995)
The WGACAT version of the ROSAT PSPC Catalogue, Rev. 1
White N.E., Giommi P., Angelini L.
<HEASARC, Code 660, LHEA/GSFC, Greenbelt (1995)>
ADC_Keywords: X-ray sources
Mission_Name: ROSAT
Description:
WGACAT is a catalogue of point sources generated at HEASARC from all
the ROSAT PSPC (Position Sensitive Proportional Counter) pointing
observations from Feb 1991 to March 1994. These were the files
available in the public archive at HEASARC as of September 1994. This
catalog is an independent research effort aimed at releasing as
quickly as possible a list of sources detected by ROSAT in its pointed
phase to:
(1) identify the detected sources,
(2) ensure their timely observation by currently active X-ray missions
e.g. ASCA,
(3) to search for objects which show exceptional time variability and
spectral properties and
(4) to provide an independent check of the detection technique used in
the official ROSAT project (SAS) processing.
WGACAT stands for N.E. White (HEASARC/GSFC). P. Giommi (ESA), and
L. Angelini (HEASARC/GSFC)
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
wgacat.dat 790 68907 The catalogue
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See also:
IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1996)
IX/11 : ROSAT Source Catalogue (1RXP), Version 1995-05-11
IX/28 : ROSAT HRI Pointed Observations (1RXH) (ROSAT Team, 1999)
J/A+AS/114/465 : ROSAT XUV Pointed Phase Source Catalogue (Kreysing+ 1995)
J/MNRAS/274/1165 : The 2RE Source Catalogue (Pye+ 1995)
http://ledas-www.star.le.ac.uk/arnie/dbhlp_WGACAT.html :
The WGA Catalog of ROSAT Point Sources Help.
Byte-by-byte Description of file: wgacat.dat
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Bytes Format Units Label Explanations
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2- 13 A12 --- 1WGA Name from this catalogue
15- 22 F8.4 deg RAdeg Right ascension of source (J2000)
24- 31 F8.4 deg DEdeg Declination of source (J2000)
33- 39 F7.1 pix Xpos The source coordinate in original pixels
41- 47 F7.1 pix Ypos The source coordinate in original pixels
49- 54 F6.2 deg GLON Galactic Longitude
56- 61 F6.2 deg GLAT Galactic Latitude
63- 71 E9.2 ct/s Count Background subtracted count rate accumulated
in PHA bins 24 to 224 (0.24-2.0keV)
73- 80 E8.1 ct/s e_Count Mean error on Count
82- 92 E11.4 mW/m2 Fx X-ray flux using a constant correction factor
of 1.5x10-11 mW/m2 (erg/s/cm2).
94- 97 F4.2 --- VigFactor Telescope vignetting correction (1)
99-100 I2 arcsec ErrorRad 90% confidence source error radius.
102-105 I4 arcsec BoxSize Optimum source box size.
107-114 F8.4 deg RAc.deg Image center right ascension. (2)
116-123 F8.4 deg DEc.deg Image center declination. (2)
125-130 F6.3 arcmin offset1 Offset of detected position from (RAc,DEc)
132-139 F8.4 deg RAt.deg Target right ascension (3)
141-148 F8.4 deg DEt.deg Target declination (3)
150-155 F6.3 arcmin offset2 Offset of detected position from (RAt,DEt)
157-172 A16 --- OBJECT Original field name as found in event list
174-179 I6 --- ROR [100000/901000] number of unique sequences
181-186 A6 "YY.DDD" StartDay Starting day of observation
("DDD" in 001-366 range)
188-193 A6 "YY.DDD" EndDay Ending day of observation
195-196 I2 --- Ndetect Total number of detections in the image.
198-199 I2 --- IDno The source number in the field (4)
201-215 A15 --- ImageFile FITS image file name
217-227 A11 --- EventFile Event file name
229-246 A18 --- SourceID Unique source identification (5)
248-257 E10.3 --- PrBkg Probability that the detection is a
background fluctuation
259-264 F6.2 --- SNR The signal to noise ratio of the source
266-267 I2 --- Qual [1/10] Quality flag from bad to good (6)
269 A1 --- Region [I/O] Region of the ROSAT image (I=in, O=out)
271-272 I2 --- Zoom Rebinning factor of the image
274-284 E11.4 ct/pix/s Bgnd Background count rate
286-291 I6 s ExpTime Exposure time of the field
293-300 F8.4 --- SR1 Softness ratio 11-39/40-85 (7)
302-309 F8.4 --- e_SR1 Mean error on SR1
311-318 F8.4 --- HR1 Hardness ratio 86-200/40-85 (7)
320-327 F8.4 --- e_HR1 Mean error on HR1
329-336 F8.4 --- SR2 Hard softness ratio 50-86/87-129 (7)
338-345 F8.4 --- e_SR2 Mean error on SR2
347-354 F8.4 --- HR2 Hard hardness ratio 130-240/87-129 (7)
356-363 F8.4 --- e_HR2 Mean error on HR2
365-371 I7 ct Counts Total number of counts detected
373-379 F7.2 ct e_Counts Mean error on Counts
381-387 I7 ct Count1 Low band (11-39=0.1-0.4keV) counts
389-395 F7.2 ct e_Count1 Mean error on Count1
397-403 I7 ct Count2 Mid band (40-85=0.4-0.9keV) counts
405-411 F7.2 ct e_Count2 Mean error on Count2
413-419 I7 ct Count3 High band (86-200=0.92.0keV) counts
421-427 F7.2 ct e_Count3 Mean error on Count3
429-436 F8.3 --- Chi2 Variability test (8)
438 I1 --- XidFlag [1]? 1 if id with pre-Rosat X-ray source
440-453 A14 --- Xid1 First name of X-ray identifier
455-468 A14 --- Xid2 2nd name of X-ray identifier
470-483 A14 --- Xid3 3rd name of X-ray identifier
485-495 E11.4 ct/s IPCcount ? Count rate detected by the Einstein IPC.
497-507 E11.4 ct/s e_IPCcount ? Mean error on IPCcount
509-519 E11.4 --- IPC/PSPC ? Ratio of IPC/PSPC count rates.
521-531 E11.4 --- e_IPC/PSPC ? Mean error on IPC/PSPC
533 I1 --- OIdFlag [1]? 1 if ID with optical source
535-548 A14 --- OId1 First name of optical counterpart
550-563 A14 --- OId2 2nd name of optical counterpart
565-578 A14 --- OId3 3rd name of optical counterpart
580-593 A14 --- OId4 4th name of optical counterpart
595-608 A14 --- SIMBAD Name in SIMBAD data-base (if existing)
610-614 F5.2 mag Vmag ? V magnitude of any optical counterpart
616-626 E11.4 --- Fx/Fo ? X-ray over optical flux ratio
628-637 E10.3 --- AoX ? Optical to X-ray slope
639-644 F6.4 --- z ? Redshift of counterpart
646-657 A12 --- Class Source classification
659 I1 --- RIdFlag [1]? 1 if ID with radio source
661-674 A14 --- RId1 First name of radio source
676-689 A14 --- RId2 First name of radio source
691-702 A12 --- IRAS Name in IRAS (II/125 or II/156)
704-706 A3 --- IdCat [HIC ] Catalog used for optical position (9)
708-715 F8.3 arcmin IDoffset ? Offset of Id star from ROSAT position
717-724 F8.3 arcmin oRA ? Offset from reference star (9)
726-733 F8.3 arcmin oDE ? Offset from reference star (9)
735 I1 --- WGAversion [1]? Version of WGACAT
737-750 A14 --- MPEname Name in MPE catalog IX/11
752 I1 --- MPEflag [1,3]? Comparison with MPE IX/11 (10)
754-763 E10.3 ct/s MPEcount ? Count from MPE
765-774 E10.3 ct/s e_MPEcount ? Mean error on MPEcount
776-784 E9.2 cm-2 NH21cm ? 21cm number of H from Starke et al.
786-790 F5.2 mag B-V ? B-V colour
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Note (1): the vignetting factor increases from 1 for sources detected
on the axis to higher values when the source was detected off-axis.
Note (2): the image center corresponds roughly to the pointing position.
Note (3): the target position are the coordinates of the primary
target in the field which can be different from (RAc, DEc)
Note (4): the source number increases outwards from the center of
the image. Note that this number is unique only with the processed
region (eg. inner or outer). In the same field two sources can have
the same IDno but the parameter Region will be 'I' and 'O'.
Note (5): the unique source ID is composed by
xxnnnnnnnregionidno, where
xx is either 'RP' for US sequence and 'WP' for German/UK sequence,
nnnnnnnn is the ROR number,
region is either 'O' for source detected in the outer region
or 'I' for source detected in the inner region,
idno is the source number detected in the field.
Note this ID is unique only within a given revision.
Note (6): Detailed meaning of the Qflag:
9 or 10 indicates a secure detection of a point source, which has
been confirmed by visual inspection of each source (using the
thumb nail GIFs available through BROWSE).
8 indicates that the entire field has been inspected, and there was no
obvious problem with the detections in the field as a whole, and
that it is reasonably secure. This is different from Qflag 9 or 10
because each source has not been individually identified.
5-7 indicates that there is something suspicious in the field. This
might simply mean that there is a bright source, which makes the
contrast on the image such that it is hard to see the fainter sources.
But it may also indicate a cluster of detections suggesting extended
emission. These fields should be double checked by eye to ensure the
detection is real. It is suggested in this case to inspect the
corresponding intensity map.
4 indicates that many (typically more than half) the detections are
caused by extended emission, but that there are still good sources
(typically a small fraction over the total number of detection).
3 indicates a source that looks perfectly good, is really bad. This
may result from a local arc in the detector caused by a temporary
HV breakdown or by a mystery pointing that interrupts the sequence.
2 was assigned to all fields taken in the first 2 months of the
mission (before the six month survey phase began) where the
processing and satellite were not stable. Probably most of the
detection found in those field are correct, but it require either
a checking of the housekeeping parameters or that the processing
to create the final event list was correct.
1 indicates most if not all of the detections in that field are
spurious, because of a large extended object.
0 means the field has not been quality checked.
For an ultra clean source use Qflag≥5.
Note (7): the ratios are defined by
(PHA bins) (keV ranges)
SR1 11-39/40-85 0.1-0.4/0.4-0.9
HR1 86-200/40-85 0.9-2.0/0.4-0.9
SR2 50-86/87-129 0.5-0.9/0.9-1.3
HR2 130-240/87-129 1.3-2.4/0.9-1.3
Note (8): the The Chi2 value is obtained in comparing the time
arrival distribution of the photons collected in each detection
box with the corresponding distribution of the entire image using
a Kolmogorov-Smirnov (KS) test. The result of the KS test is
a chi2 value with 2 d.o.f.
A value >100 is really variable.
Note (9): Only HIC (Hipparcos Input Catalog, Turon et al. I/196)
Note (10): This flag contains the following values:
1: source within 20 arcsec in inner region
2: source within 60 arcsec in outer region
3: this field is included in the ROSATSRC catalog,
but the source is not detected.
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History:
The file was created from the "large_wgacat.txt" file copied at
copied at ftp://legacy.gsfc.nasa.gov/rosat/wgacat/files/rev1;
the file was dated April 9, 1995.
Most of the non-empty fields of the large_wgacat.txt have been
kept to generate the "wgacat.dat" file; noticeable exceptions
are the columns extracted from GSC, from IRAS and from radio
catalogues.
Contact persons:
Any questions about, or problems with, the WGA catalogue should be
addressed to Nick White, Paolo Giommi and Lorella Angelini at
References:
Giommi, P. et al. 1991, Ap.J., 378, 77
Giommi, P., Angelini, L., Jacobs P., Tagliaferri, G., 1991, in
"Astronomical Data Analysis Software and Systems I" ,
D.M.Worrall, C. Biemesderfer and J. Barnes eds, 1991,
A.S.P. Conf. Ser. 25, 100
Giommi, P., White, N.E. and Angelini, L., 1994, in
"Astronomical Data Analysis Software and Systems VI", in press.
Giommi, P. et al. 1995, in preparation.
Maccacaro, T., et al. 1988, Ap.J., 326, 680.
Pallavicini, R., et al. 1981, Ap.J., 248, 279.
Stark, et al. private communication
(End) Francois Ochsenbein [CDS] 22-Oct-1996