XMM-OM Serendipitous Ultraviolet Source Survey catalogue: SUSS4

The catalogue was compiled for the Optical Monitor instrument on board the ESA XMM Newton observatory. This version, the 4th release of the catalogue, spans the period of observations from 2000 to July 2017.

A detailed description of the Catalogue can be found here. A refereed paper on the first version can be found in Page M.J. et al. (2012).

In addition to covering a larger observation period, the fourth release differs from the previous one in the implementation of a new time dependent sensitivity degradation correction. As in the previous release, sources detected on stacked images are properly flagged.

All data have been fully processed at the European Space Astronomy Centre (ESAC, Madrid, Spain) by using the XMM Science Analysis Software (SAS) system version 17.0.

The number of observations (OBSIDs) included in the catalogue is 9,749.
The total number of entries in this release is 8,176,156. They correspond to 5,503,765 sources, of which 1,035,453 have multiple entries in the source table, corresponding to different observations.

The Catalogue consists of two tables. The first one (SRCLIST) contains the sources, with positional and photometric data (count rate, magnitude and flux) and quality flags for each measurement. The content of the different columns (114) is:

IAUNAME Source IAU name
N_SUMMARY Index in the SUMMARY table for the source OBSID
OBSID Source OBSID number
SRCNUM Source number in this catalogue
UVW2_SRCDIST Dist. to the nearest source, UVW2 filter
UVM2_SRCDIST Dist. to the nearest source, UVM2 filter
UVW1_SRCDIST Dist. to the nearest source, UVW1 filter
U_SRCDIST Dist. to the nearest source, U filter
B_SRCDIST Dist. to the nearest source, B filter
V_SRCDIST Dist. to the nearest source, V filter
RA Source Right Ascension coordinate (deg)
DEC Source Declination coordinate (deg)
RA_HMS Source Right Ascension in hour units
DEC_DMS Source Declination coordinate in DMS
POSERR Source positional (coordinate) error
LII Source galactic longtude
BII Source galactic latitude
N_OBSID Number of observation IDs for this source
UVW2_SIGNIF Source significance for the filter UVW2
UVM2_SIGNIF Source significance for the filter UVM2
UVW1_SIGNIF Source significance for the filter UVW1
U_SIGNIF Source significance for the filter U
B_SIGNIF Source significance for the filter B
V_SIGNIF Source significance for the filter V
UVW2_RATE Source count rate for the filter UVW2
UVW2_RATE_ERR Source count rate error, filter UVW2
UVM2_RATE Source count rate for the filter UVM2
UVM2_RATE_ERR Source count rate error, filter UVM2
UVW1_RATE Source count rate for the filter UVW1
UVW1_RATE_ERR Source count rate error, filter UVW1
U_RATE Source count rate for the filter U
U_RATE_ERR Source count rate error, filter U
B_RATE Source count rate for the filter B
B_RATE_ERR Source count rate error, filter B
V_RATE Source count rate for the filter V
V_RATE_ERR Source count rate error, filter V
UVW2_AB_FLUX Source flux for the filter UVW2
UVW2_AB_FLUX_ERR Source flux error for the filter UVW2
UVM2_AB_FLUX Source flux for the filter UVM2
UVM2_AB_FLUX_ERR Source flux error for the filter UVM2
UVW1_AB_FLUX Source flux for the filter UVW1
UVW1_AB_FLUX_ERR Source flux error for the filter UVW1
U_AB_FLUX Source flux for the filter U
U_AB_FLUX_ERR Source flux error for the filter U
B_AB_FLUX Source flux for the filter B
B_AB_FLUX_ERR Source flux error for the filter B
V_AB_FLUX Source flux for the filter V
V_AB_FLUX_ERR Source flux error for the filter V
UVW2_AB_MAG Source AB magnitude for the filter UVW2
UVW2_AB_MAG_ERR Source AB magnitude error, filter UVW2
UVM2_AB_MAG Source AB magnitude for the filter UVM2
UVM2_AB_MAG_ERR Source AB magnitude error, filter UVM2
UVW1_AB_MAG Source AB magnitude for the filter UVW1
UVW1_AB_MAG_ERR Source AB magnitude error, filter UVW1
U_AB_MAG Source AB magnitude for the filter U
U_AB_MAG_ERR Source AB magnitude error, filter U
B_AB_MAG Source AB magnitude for the filter B
B_AB_MAG_ERR Source AB magnitude error, filter B
V_AB_MAG Source AB magnitude for the filter V
V_AB_MAG_ERR Source AB magnitude error, filter V
UVW2_VEGA_MAG Source Vega magnitude for the filter UVW2
UVW2_VEGA_MAG_ERR Source Vega magnitude error, filter UVW2
UVM2_VEGA_MAG Source Vega magnitude for the filter UVM2
UVM2_VEGA_MAG_ERR Source Vega magnitude error, filter UVM2
UVW1_VEGA_MAG Source Vega magnitude for the filter UVW1
UVW1_VEGA_MAG_ERR Source Vega magnitude error, filter UVW1
U_VEGA_MAG Source Vega magnitude for the filter U
U_VEGA_MAG_ERR Source Vega magnitude error, filter U
B_VEGA_MAG Source Vega magnitude for the filter B
B_VEGA_MAG_ERR Source Vega magnitude error, filter B
V_VEGA_MAG Source Vega magnitude for the filter V
V_VEGA_MAG_ERR Source Vega magnitude error, filter V
UVW2_MAJOR_AXIS Source major semi-axis for the filter UVW2
UVM2_MAJOR_AXIS Source major semi-axis for the filter UVM2
UVW1_MAJOR_AXIS Source major semi-axis for the filter UVW1
U_MAJOR_AXIS Source major semi-axis for the filter U
B_MAJOR_AXIS Source major semi-axis for the filter B
V_MAJOR_AXIS Source major semi-axis for the filter V
UVW2_MINOR_AXIS Source minor semi-axis for the filter UVW2
UVM2_MINOR_AXIS Source minor semi-axis for the filter UVM2
UVW1_MINOR_AXIS Source minor semi-axis for the filter UVW1
U_MINOR_AXIS Source minor semi-axis for the filter U
B_MINOR_AXIS Source minor semi-axis for the filter B
V_MINOR_AXIS Source minor semi-axis for the filter V
UVW2_POSANG Source position angle for the filter UVW2
UVM2_POSANG Source position angle for the filter UVM2
UVW1_POSANG Source position angle for the filter UVW1
U_POSANG Source position angle for the filter U
B_POSANG Source position angle for the filter B
V_POSANG Source position angle for the filter V
UVW2_QUALITY_FLAG Source quality flag for the filter UVW2
UVM2_QUALITY_FLAG Source quality flag for the filter UVM2
UVW1_QUALITY_FLAG Source quality flag for the filter UVW1
U_QUALITY_FLAG Source quality flag for the filter U
B_QUALITY_FLAG Source quality flag for the filter B
V_QUALITY_FLAG Source quality flag for the filter V
UVW2_QUALITY_FLAG_ST Source quality flag string, filter UVW2
UVM2_QUALITY_FLAG_ST Source quality flag string, filter UVM2
UVW1_QUALITY_FLAG_ST Source quality flag string, filter UVW1
U_QUALITY_FLAG_ST Source quality flag string, filter U
B_QUALITY_FLAG_ST Source quality flag string, filter B
V_QUALITY_FLAG_ST Source quality flag string, filter V
UVW2_EXTENDED_FLAG Source extended flag for the filter UVW2
UVM2_EXTENDED_FLAG Source extended flag for the filter UVM2
UVW1_EXTENDED_FLAG Source extended flag for the filter UVW1
U_EXTENDED_FLAG Source extended flag for the filter U
B_EXTENDED_FLAG Source extended flag for the filter B
V_EXTENDED_FLAG Source extended flag for the filter V
UVW2_SKY_IMAGE Source detected in stacked images filter UVW2
UVM2_SKY_IMAGE Source detected in stacked images filter UVM2
UVW1_SKY_IMAGE Source detected in stacked images filter UVW1
U_SKY_IMAGE Source detected in stacked images filter U
B_SKY_IMAGE Source detected in stacked images filter B
V_SKY_IMAGE Source detected in stacked images filter V
 

In the second table (SUMMARY) we give a summary of the observations from which the sources have been detected and measured. The content of the columns (35) in this table is: 

N_SUMMARY Reference index for the source OBSID data
REVOLUTION XMM revolution number
OBSID Observation ID number
TARGET Observation target name
FILTERS XMM OM filter names used in this observation
MJD_START Initial observation date/time
MJD_END End of observation date/time
RA_PNT Right Ascension of the telescope pointing direc
DEC_PNT Declination of the telescope pointing direction
RA_PNT_HMS Right Ascension of the telescope pointing in HM
DEC_PNT_DMS Declination of the telescope pointing in DMS
EXPOSURE_UVW2 Total exposure time for the filter UVW2
EXPOSURE_UVM2 Total exposure time for the filter UVM2
EXPOSURE_UVW1 Total exposure time for the filter UVW1
EXPOSURE_U Total exposure time for the filter U
EXPOSURE_B Total exposure time for the filter B
EXPOSURE_V Total exposure time for the filter V
N_SOURCES Total number of sources
N_SOURCES_UVW2 Number of sources for the filter UVW2
N_SOURCES_UVM2 Number of sources for the filter UVM2
N_SOURCES_UVW1 Number of sources for the filter UVW1
N_SOURCES_U Number of sources for the filter U
N_SOURCES_B Number of sources for the filter B
N_SOURCES_V Number of sources for the filter V
DETLIM_UVW2 Vega magnitude limit for the filter UVW2
DETLIM_UVM2 Vega magnitude limit for the filter UVM2
DETLIM_UVW1 Vega magnitude limit for the filter UVW1
DETLIM_U Vega magnitude limit for the filter U
DETLIM_B Vega magnitude limit for the filter B
DETLIM_V Vega magnitude limit for the filter V
RAOFFSET Corrected offset in Right Ascension
DECOFFSET Corrected offset in Declination
RAOFFSET_ERR Standard error of the RA offset
DECOFFSET_ERR Standard error of the DEC offset
OFFSET_RMS Offset RMS
 

The meaning of the quality flags (columns filter_QUALITY_FLAG and filter_QUALITY_FLAG_ST) in the SRCLIST table are as follows:

bit 0 (value 1) source on a bad pixel
bit 1 (value 2) source on a readout streak
bit 2 (value 4) source on a smoke-ring
bit 3 (value 8) source on a diffraction spike
bit 4 (value 16) source affected by Mod-8 pattern
bit 5 (value 32) source within the central enhancement
bit 6 (value 64) source near a bright source
bit 7 (value 128) source near the edge
bit 8 (value 256) point source within an extended source
bit 9 (value 512) weird source (bright pixel)
bit 10 (value 1024) multiple exposure values within photometry aperture
bit 11 (value 2048) the source is too bright (rate > 0.97 c/frame)
 

The columns filter_SKY_IMAGE indicate if a source has been detected in stacked (sky) images obtained with that filter. The catalogue contains 948,277 such detections, with 60,889 sources having multiple detections in different observations.

A cross-match of the whole catalogue with GAIA DR2 data set, using a search radius of 3 arcsec gives 82% matches. Detections in the V filter have 89% matches.

The XSA provides access to the OM Catalogue as a complete download of the file (~1 Gb, compressed fits format) as well as through a search interface whose results can be stored by the user in several formats. It should be noted that this interface allows the user to access only part of the information contained in the catalogue: source coordinates, magnitude and flux and their corresponding errors and quality flags. A reduced version of the complete catalogue (500 Mb, compressed fits format) can be downloaded as well.

The ESA-Sky utility allows the user to display the sources from the catalogue on top of sky images from different instruments at all wavelengths. This includes also images obtained with OM in two color combination, Visible (U, B and V OM filters) and UV (UVW1, UVM2 and UVW2 OM filters). It should be noted that OM images have a low dynamic range.