LEDAS  
Leicester Database and Archive Service
 
ARNIE Index
ARNIE Help
ARNIE Tutorial
Search...
All databases
All helpfiles
Line
Footer
E-mail

XMMOMOBJ: Help

XMMOMOBJ - XMM-Newton OM Objects


Overview

The Optical Monitor Catalog of serendipitous sources (OMCat) contains entries for every source detected in the publically available XMM-Newton Optical Monitor (OM) images taken in either the imaging or "fast" modes. Since the OM records data simultaneously with the X-ray telescopes on XMM-Newton, it typically produces images in one or more near-UV/optical bands for every pointing of the observatory. As of the beginning of 2006, the data in the public archive covered roughly 0.5% of the sky in 2950 fields. The OMCat is not dominated by sources previously undetected at other wavelengths; the bulk of objects have optical counterparts. However, the OMCat can be used to extend optical or X-ray spectral energy distributions for known objects into the ultraviolet, to study at higher angular resolution objects detected with GALEX, or to find high-Galactic-latitude objects of interest for UV spectroscopy.

References

OMCat: Catalogue of Serendipitous Sources Detected with the XMM-Newton
Optical Monitor
    Kuntz, K.D., Harrus, I.M., McGlynn, T.A., Mushotzky, R.F., Snowden S.L.
   <...(2008)>
   =2008...K  (SIMBAD/NED Bibcode)

Provenance

This table was created by the HEASARC in March 2008, based on a table supplied by the authors.

Parameters

ObsID
A unique XMM-Newton observation identifier made up of the proposal number, target number of the proposal, and exposure number of the target.

Obj_Num
A unique target counter for the OM source within the observation specified by the obsid. Thus, the combination of obsid and obj_num uniquely identifies an entry in this table.

RA
The Right Ascension of the OM source in the selected equinox.

Dec
The Declination of the OM source in the selected equinox.

LII
The Galactic Longitude of the OM source.

BII
The Galactic Latitude of the OM source.

Error_Radius
The position error of the OM source, in arcseconds.

Time
The start time of the observation in which the OM source was detected.

Exposure
The duration of the exposure in which the OM source was detected.

RMS_Res
The RMS residuals in the fit of the OM source with the USNO Catalog, in arcseconds.

Count_Rate
The OM source count rate, in ct/s.

Count_Rate_Error
The error in the OM source count rate, in ct/s.

SNR
The significance of the OM source detection.

Band
The magnitude band of the filter in which the OM source was detected: V, B, U, UVW1, UVM2, UVW2, or WHITE. The properties of the OM filters are given in Table 2 of the reference paper.

Mag
The measured magnitude of the OM source in the particular band in which it was observed, derived from the observed count rate and the particular filter properties in the standard way.

Mag_Error
The error in the meassured magnitude of the OM source in the particular band in which it was observed.

Semi_Major_Axis
The semi-major axis of the OM source, if extended, in arcseconds.

Semi_Minor_Axis
The semi-minor axis of the OM source, if extended, in arcseconds.

Position_Angle
The position angle of the major axis of the OM source, if extended, in degrees.

Quality
This flag parameter (called Q_FLAG in the reference paper) is set to 0 for OM sources with good data quality. The following positive values are used to flag compromised source quality (notice that they can be used additively):

    1 = bad pixel
    2 = source on possible read-out streak
    4 = source on possible smoke ring
    8 = source on possible star diffraction spike
   16 = source likely affect by mod-8 pattern
   32 = source near bright source
   64 = source within central enhanced region
  

Confused
This flag parameter (called C_FLAG in the reference paper) is set to 0 for OM sources which are unconfused. The following positive values are used to flag different types of confusion (notice that they can be used additively):

    1 = one or more sources lie within a radius of 6 to 1 unbinned pixels
    2 = one or more sources lie within a radius of 6 unbinned pixels
    4 = source near an image edge
    8 = point source lies partly or entirely within an extended source region
  

Extended
This flag parameter (called E_FLAG in the reference paper) is set to 0 for OM sources which are non-extended, and to 1 for extended sources.


Contact Person

Questions regarding the XMMOMOBJ database table can be addressed to the HEASARC User Hotline.
If you have any problems, please consult the help page or mail ledas-help@star.le.ac.uk
 
HOME
SEARCH
SERVICES INFO SOFTWARE ViZieR BLASTA DSS
ARCHIVES ASCA CHANDRA GINGA ROSAT ARNIE