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SourceListFile

XMM-Newton Science Analysis System

omdetect (omdetect-5.14.2) [???]

Meta Index / Home Page

SourceListFile

The source-list file produced by omdetect contains a list of the positions of all the detected sources, the parameterizations of their shapes, their extracted count-rates, and corrected count-rateswhich contain some of the corrections that are needed to convert the raw rates to the rates that can be used to compute instrumental magnitutes. Fully corrected count-rates and instrumental magnitudes are obtained by running ommag, with its parameter ``set'' set to the omdetect source-list.

The source-list file is in FITS file format and contains a SRCLIST table with the columns shown in the following table.

COLUMN NAME
KIND UNITS DESCRIPTION

SRCNUM
INT 32 none Source number - order of detection

XPOS FLOAT pixels x-coordinate of centroided source centre

YPOS FLOAT pixels y-coordinate of centroided source centre

POSERR FLOAT pixels error in x and y centroided position

RATE FLOAT counts/sec Total measured source counts (after background subtraction) within default source extraction aperture (r=12 un-binned pixels), divided by exposure time.

RATE_ERR
FLOAT counts/sec Error in the raw rate

BACKGROUND_RATE
FLOAT counts/sec Total estimated background counts (scaled by area ratio, from the background annulus) within default source extraction aperture, divided by exposure time

SIGNIFICANCE
FLOAT none source counts / sqrt(source + 2 $\times$ background counts) (i.e. signal-to-noise ratio), where the counts refer to the rawcounts, before any corrections have been applied.

CORR_RATE
FLOAT counts/sec Background subtracted source count rate after applying PSF (if necessary) and coincidence-loss corrections.

CORR_RATE_ERR
FLOAT counts/sec Error in the corrected rate

CORR_BACKGROUND _RATE
FLOAT counts/sec BACKGROUND_RATE after correcting for coincidence losses.

PSF1_CORR
FLOAT % percentage Point-spread function correction applied to extrapolate the RATE value from measurement aperture area to the default extraction area of 12 unbinned pixels

SPB_COILOSS
FLOAT none Coincidence-loss correction applied to the source plus background rate (coincidence-loss corrected total count-rate/raw total count-rate)

BK_COILOSS
FLOAT none Coincidence-loss correction applied to the raw-background rate (coincidence-loss corrected background count-rate/raw background count-rate)

NOPIXELS
INT 32 none Number of pixels contained by an extended source (EFLAG=1). Point-sources (EFLAG=1) will have this value set to zero.

APERTURE FLOAT unbinned pixels For point sources (EFLAG=0), the aperture radius (unbinned pixels) used in the photometry. For extended-sources (EFLAG=1) this value will be set to NULL.

FWHM_MAJ
FLOAT arcsecs The full-width-at-half-maximum of the semi-major axis of the ellipse describing the shape of the source (computed by moments - Set to NULL if a reliable value couldn't be computed.)

FWHM_MAJ_ERR FLOAT arcsecs The computed error of the major-axis

FWHM_MIN FLOAT arcsecs The full-width-at-half-maximum of the semi-minor axis of the ellipse describing the shape of the source (computed by moments - Set to NULL if a reliable value couldn't be computed.)

FWHM_MMIN_ERR FLOAT arcsecs The computed error of the minor-axis

PA FLOAT degrees The position-angle (measured anti-clockwise from the positive x-axis) of the semi-major axis of the ellipse describing the shape of the source (computed from moments - Set to NULL if a reliable value couldn't be computed.)

PA_ERR FLOAT degrees The computed error of the position angle

QFLAG INT 16 none Source quality flag - Please see below

CFLAG INT 8 none Source confusion flag - Please see below

EFLAG INT 8 none (source extension flag) Either 0

point-source (none-extended) or 1 extended.

COLUMN NAME	KIND	UNITS	DESCRIPTION
SRCNUM	INT 32	none	Source number - order of detection
XPOS	FLOAT	pixels	x-coordinate of centroided source centre
YPOS	FLOAT	pixels	y-coordinate of centroided source centre
POSERR	FLOAT	pixels	error in x and y centroided position
RATE	FLOAT	counts/sec	Total measured source counts (after background subtraction) within default source extraction aperture (r=12 un-binned pixels), divided by exposure time.
RATE_ERR	FLOAT	counts/sec	Error in the raw rate
BACKGROUND_RATE	FLOAT	counts/sec	Total estimated background counts (scaled by area ratio, from the background annulus) within default source extraction aperture, divided by exposure time
SIGNIFICANCE	FLOAT	none	source counts / sqrt(source + 2 $\times$ background counts) (i.e. signal-to-noise ratio), where the counts refer to the rawcounts, before any corrections have been applied.
CORR_RATE	FLOAT	counts/sec	Background subtracted source count rate after applying PSF (if necessary) and coincidence-loss corrections.
CORR_RATE_ERR	FLOAT	counts/sec	Error in the corrected rate
CORR_BACKGROUND _RATE	FLOAT	counts/sec	BACKGROUND_RATE after correcting for coincidence losses.
PSF1_CORR	FLOAT	%	percentage Point-spread function correction applied to extrapolate the RATE value from measurement aperture area to the default extraction area of 12 unbinned pixels
SPB_COILOSS	FLOAT	none	Coincidence-loss correction applied to the source plus background rate (coincidence-loss corrected total count-rate/raw total count-rate)
BK_COILOSS	FLOAT	none	Coincidence-loss correction applied to the raw-background rate (coincidence-loss corrected background count-rate/raw background count-rate)
NOPIXELS	INT 32	none	Number of pixels contained by an extended source (EFLAG=1). Point-sources (EFLAG=1) will have this value set to zero.
APERTURE	FLOAT	unbinned pixels	For point sources (EFLAG=0), the aperture radius (unbinned pixels) used in the photometry. For extended-sources (EFLAG=1) this value will be set to NULL.
FWHM_MAJ	FLOAT	arcsecs	The full-width-at-half-maximum of the semi-major axis of the ellipse describing the shape of the source (computed by moments - Set to NULL if a reliable value couldn't be computed.)
FWHM_MAJ_ERR	FLOAT	arcsecs	The computed error of the major-axis
FWHM_MIN	FLOAT	arcsecs	The full-width-at-half-maximum of the semi-minor axis of the ellipse describing the shape of the source (computed by moments - Set to NULL if a reliable value couldn't be computed.)
FWHM_MMIN_ERR	FLOAT	arcsecs	The computed error of the minor-axis
PA	FLOAT	degrees	The position-angle (measured anti-clockwise from the positive x-axis) of the semi-major axis of the ellipse describing the shape of the source (computed from moments - Set to NULL if a reliable value couldn't be computed.)
PA_ERR	FLOAT	degrees	The computed error of the position angle
QFLAG	INT 16	none	Source quality flag - Please see below
CFLAG	INT 8	none	Source confusion flag - Please see below
EFLAG	INT 8	none	(source extension flag) Either 0
point-source (none-extended) or 1 extended.

Subsections

XMM-Newton SOC/SSC -- 2008-10-22