The purpose of this page is to describe the column layout of eROSITA FITS source catalogues as they are produced by the eROSITA Science Analysis Software System (eSASS). The structure of source catalogues published with the EDR by individual authors may differ.
On this page
The first letter of the standard products file names designates the type of catalog:
p: pointing
l: slew
f: field scan
The product type part of the standard products file name is 'SourceCatalog', which is followed by "_" and "c001".
First 16 characters: same as final data products file name
Next 7 character: two caracter code of detection algorithm, followed by five digit
source number (ID_SRC from detection source list)
Last 9 characters: dataset version and processing configuration as in final prodcuts file name
Example: pm00_700001_001_ML00001_001_c001 (pointing)
First digit: "p" for pointing
Next 7 digits: survey field number, followed by "_"
Last 5 digits: source number within survey field
Example: s123332_00123
Only objects not detected in the survey should be given a pointing souIDs.
The ERMLDET source lists contain one row per energy band and per telescope
for each source in addition to columns containing summed up results.
ID_SRC I*4 Source number
BOX_ID_SRC I*4 Source number from ERBOX input source list
ID_INST I*4 Telescope number [1..7: per telescope,
8..9: groups of telescopes
0: total]
ID_BAND I*4 Band number [1..n: band specific results,
0: total]
ID_CLUSTER I*4
X_IMA R*4 [pixels] Image pixel coordinate
X_IMA_ERR R*4 [pixels] ERMLDET error in X direction
Y_IMA R*4 [pixels] Image pixel coordinate
Y_IMA_ERR R*4 [pixels] ERMLDET error in Y direction
RA R*8 [deg] Right ascension
DEC R*8 [deg] Declination
RADEC_ERR R*4 [sec] Combined ERMDLET error
LII R*8 [deg] Galactic longitude
BII R*8 [deg] Galactic latitutde
EXT R*4 [arcsec] Source extent
EXT_ERR R*4 [arcsec] 1 sigma error
ML_CTS R*4 [counts] Source counts
ML_CTS_ERR R*4 [counts] 1 sigma error
ML_RATE R*4 [counts/sec] Vignetting corrected count rate
ML_RATE_ERR R*4 [counts/sec] 1 sigma error
ML_FLUX R*4 [cgs] Source flux
ML_FLUX_ERR R*4 [cgs] 1 sigma error
DET_LIKE R*4 Detection likelihood 1
EXT_LIKE R*4 Extent likelihood 1
ML_BKG R*4 [counts/arcmin^2] Background at source location
ML_EXP R*4 [sec] Vignetting corrected exposure at source location
ML_RADIUS R*4 [arcsec] ERMLDET source cut-out radius
ML_EFF R*4 Fraction of PSF inside cut-out radius
MASKFRAC R*4 Fraction of extraction area within detection mask
DIST_NN R*4 [arcsec] Distance to nearest neighbor
OWNER I*1 IKI/MPE sky ownership
1 expressed as -ln(p) where p is the probability of the detection/the extent being due to Poissonian background fluctuations
Only for pointings (NULL otherwise)
OFFAX R*4 [arcmin] Off-axis angle of source
VIGNET R*4 Mean Vignetting factor at source position
ONTIME R*4
Only for single-camera detection mode (NULL otherwise)
TM_NR I*1 Telescope modul number
Only for pointings in single-camera detection mode (NULL otherwise)
RAWX R*4 Mean detector pixel position of source center
RAWY R*4 Mean detector pixel position of source center
Only for different energy bands (NULL otherwise) **** has to be checked ****
HRn R*4 Hardness ratio between energy band n and n+1
HRn_ERR R*4 Hardness ratio error
Aperture photometry information (written by task APETOOL, NULL otherwise):
APE_CTS I*4 [counts] Counts in aperture
APE_BKG R*4 [counts] Background in aperture
APE_EXP R*4 [s] Mean exposure in aperture
APE_EEF R*4 Fraction of PSF in aperture
APE_RADIUS R*4 [pixels] Aperture radius
APE_POIS R*4 Poissonian probability of APE_CTS, given APE_BKG
The final source catalogs provide the information in the ERMLDET source lists as well as supplementary information created by the tasks CATUPDATE, APETOOL, DPVALP, and DPVALI in a one line per source layout. Final source catalogs are created for each all-sky survey field or pointing by the tasks CATPREP and CATUPDATE in t he SOU chain of the pipeline. In the case of all-sky survey fields, catalogs per single scan, 6 month eRASS, and cumulative multi-eRASS source detection runs are created. Each catalog exists for multiple pipeline configurations and multiple dataset versions, as designated by the version and configuration numbers in their products file names. The individual sky-field catalogs are periodically merged by task CATMERGE into full hemisphere and multi-time-epoche catalogs. The cumulative and merged catalogs are stored in the products archive in directory /ero_archive/products/catalogs from where they will be ingested into the eROSE tool.
The columns are grouped into different sections for better legibility. The eSASS tasks
creating the information in each section are marked in brackets.
Source IDs and spatial information (ERMLDET, CATPREP, CATUPDATE):
ID_SRC I*4 Source ID from ERMLDET run
ID_CLUSTER I*4 Cluster ID from ERMLDET run
(objects fit simultaneously have same cluster ID)
detUID C*32 Unique detection ID
souUID C*14 Unique source ID
IAUNAM C*32 IAU name corresponding to souUID
OWNER I*1 IKI/MPE sky ownership
RA R*8 [deg] Right ascension
DEC R*8 [deg] Declination
RADEC_ERR R*4 [sec] Combined ERMLDET positional error
LII R*8 [deg] Galactic longitude
BII R*8 [deg] Galactic latitude
EXT R*4 [arcsec] Source extent
EXT_ERR R*4 [arcsec] Extent error
EXT_LIKE R*4 Extent likelihood
ML_RADIUS R*4 [arcsec] ERMLDET source cut-out radius
MASKFRAC R*4 Fraction of extraction area within detection mask
NH_GAL R*4 [cm^-2] Galactic NH at source location
Source quality and source ID tracking (CATUPDATE, DPVALP, DPVALI):
QUALITY I*1 Quality number, higher is better (?)
QF I*4 Binary quality flags
NEW I*1 1: if first detection, 0 otherwise
UNIQUE I*1
SOUCONF I*4 Source confusion indicator
DIST_NN R*4 [arcsec] Distance to nearest neighbor
SRCDENS R*4 [deg^-2] Local source density
Aperture photometry information (APETOOL):
APE_CTS R*4 [counts] Counts in aperture
APE_BKG R*4 [counts] Background in aperture
APE_EXP R*4 [s] Mean exposure in aperture
APE_EEF R*4 Fraction of PSF in aperture
APE_RADIUS R*4 [arcsec] Aperture radius
APE_POIS R*4 Poissonian probability of APE_CTS, given APE_BKG
Energy band specific information (ERMLDET):
ML_CTS_n R*4 [counts] ERMLDET source counts in energy band
ML_CTS_ERR_n R*4 [counts] Source count error
ML_RATE_n R*4 [counts/s] ERMLDET source count rate in energy band
ML_RATE_ERR_n R*4 [counts/s] Source count rate error
ML_FLUX_n R*4 [cgs] Source flux derived from ML_RATE, given an energy conversion factor
ML_FLUX_ERR_n R*4 [cgs] Source flux error
DET_LIKE_n R*4 Likelihood of detection in energy band
ML_BKG_n R*4 [counts/arcmin^2] Mean background in ERMLDET source extraction area
ML_EXP_m R*4 [sec] Mean exposure in ERMLDET source extraction area
ML_EEF_m R*4 Fraction of PSF in ERMLDET source cut-out radius
with n = 0...4 for energy bands 1 to 4, 0 referring to the total band, and m = 1...4 for each energy band
Hardness ratios (ERMLDET):
HR_n R*4 Hardness ratio between energy band n and n+1
HR_n_ERR R*4 Hardness ratio error
with n = 1...3
Only for pointed observations, NULL otherwise (ERMLDET):
OFFAX R*4 [arcmin] Off-axis angle of source
VIGNET_m R*4 Mean vignetting factor at source position
with m = 1...4 for energy bands 1 to 4
IDs of potential matches (CATUPDATE):
souUID_n C*14 souUIDs of potential matches
souUID_QUAL_n R*8 Quality of potential matches
with n = 1...9
Comment:
COMMENT C*32 Comment