Data model: Data Sweep
Overview
General description:
Data sweep files are trimmed versions of the fpObjc files containing
the most commonly used (calibrated) parameters.
There is one data sweep file for each run+camcol; furthermore,
sky, star and
galaxy objects are stored in separate files.
Naming convention:
- $PHOTO_SWEEP/$RERUN/calibObj-$RUN-$CAMCOL-sky.fits.gz
- $PHOTO_SWEEP/$RERUN/calibObj-$RUN-$CAMCOL-star.fits.gz
- $PHOTO_SWEEP/$RERUN/calibObj-$RUN-$CAMCOL-gal.fits.gz
for the skies, stars and galaxies respectively. As always with SDSS,
the format for $RUN and $CAMCOL is I6.6 and I1 respectively.
These files are traditionally written out using the default
“non-ubercal”
calibrations, although there exists code to write these out in a calibrated
format. Use the CALIB_STATUS flag to check how objects were
calibrated.
Relevant photoop IDL routines :
- pro/sdssio/datasweep.pro writes out these files to the $PHOTO_SWEEP
directory.
- pro/sdssio/datasweep_recalibrate.pro recalibrates an entire $PHOTO_SWEEP directory
(based on the $PHOTO_CALIB environment variable) and copies
it over to a new directory. It also includes the CALIB keyword into the FITS header
that stores the value of $PHOTO_CALIB.
- pro/sdssio/sweep_readobj.pro reads in the data sweep files. Note that this
(unlike sdss_readobj.pro) does not recalibrate the data.
- pro/sdssio/sdss_recalibrate.pro calibrates a data structure based on the calibrations
stored in $PHOTO_CALIB.
- pro/sdssio/datasweep_index.pro creates the datasweep index files that allow
quick spatial searches with the IDLUTILS routine
sdss_sweep_circle.pro.
Data Sweep Star Data Model
Only contains stars (sdss_selectobj flags “objtype=’star’” and “ancestry=’unique’”)
with at least one extinction-corrected PSF magnitude brighter that [22.5, 22.5, 22.5, 22, 21.5]
in ugriz.
The stored data (with their associated types) are listed below. Where the data differ
from the standard SDSS data model, we include a brief description.
Basic SDSS object quantities
- RUN (LONG)
- RERUN (STRING)
- CAMCOL (LONG)
- FIELD (LONG)
- ID (LONG)
- OBJC_TYPE (LONG)
- OBJC_FLAGS (LONG) : Note that the 64 bit SDSS OBJC_FLAGS is split into two
- OBJC_FLAGS2 (LONG)
- ZHEDFLAG (INT) : Convenience flag (1*SATUR+ 2 * (DEBLEND & NODEBLEND) + 4 * DEBLENDED_AS_MOVING)
- OBJC_ROWC (FLOAT)
- ROWV (FLOAT)
- ROWVERR (FLOAT)
- COLV (FLOAT)
- COLVERR (FLOAT)
- COLC (FLOAT[5])
- FLAGS (LONG[5])
- FLAGS2 (LONG[5])
- RA (DOUBLE)
- DEC (DOUBLE)
SDSS Photometric quantities
- SKYFLUX (FLOAT[5]) : In nano-maggies (nmgy)
- PSFFLUX (FLOAT[5]) : nmgy
- PSFFLUX_IVAR (FLOAT[5]) : Inverse variance (ivar) in 1./nmgy^2
- MODELFLUX (FLOAT[5]) : nmgy
- MODELFLUX_IVAR (FLOAT[5]) : 1./nmgy^2
- EXTINCTION (FLOAT[5])
- APERFLUX6 (FLOAT) : Aperture flux in 6th aperture (0-indexed)
Image, resolve and calibration quantities
- PSP_STATUS (LONG[5])
- PSF_FWHM (FLOAT[5]) : In arcsec
- RESOLVE_STATUS (INT) : Resolve status (see resolve data model)
- THING_ID (LONG) : ID of thing (see resolve data model)
- IFIELD (LONG) : Field object is in (see resolve data model)
- BALKAN_ID (LONG) : Balkan object is in (see resolve data model)
- NDETECT (INT) : The number of detections of the object in the SDSS imaging (see resolve data model)
- CALIB_STATUS (INT[5]) : Ubercalibration status (see ubercalibration data model)
- NMGYPERCOUNT (FLOAT[5]) : Calibrations
The star data sweep files also include matches (within 3 arcsec) to the 2MASS PSC catalog. Refer to the
2MASS documentation for details on these flags
- TMASS_J (FLOAT) : 2MASS J-band magnitude (not flux)
- TMASS_J_IVAR (FLOAT) :
- TMASS_H (FLOAT) : 2MASS H-band magnitude (not flux)
- TMASS_H_IVAR (FLOAT)
- TMASS_K (FLOAT) : 2MASS K-band magnitude (not flux)
- TMASS_K_IVAR (FLOAT)
- TMASS_PH_QUAL (CHAR[3]) : Photometric quality flag (for JHK) (ph_qual)
- TMASS_RD_FLG (INT) : Three digit integer (for JHK) encoding read (rd\flg) flag
- TMASS_BL_FLG (INT) : Three digit integer (for JHK) encoding blend (bl_flg) flag
- TMASS_CC_FLG (CHAR[3]) : confusion and contamination flag (cc_flg)
- TMASS_GAL_CONTAM (BYTE) : Galaxy contamination flag (gal_contam)
- TMASS_MP_FLG (BYTE) : Minor planet flag (mp_flg)
- TMASS_JDATE (DOUBLE) : Julian date (jdate)
- TMASS_MATCHDIST (FLOAT) : Distance between SDSS and 2MASS object (degrees)
- TMASS_NMATCH (INT) : Number of matches in the 2MASS PSC
Data Sweep Galaxy Data Model
Only contains galaxies (sdss_selectobj flags “objtype=’gal’” and “ancestry=’unique’”)
with at least one extinction-corrected model magnitude brighter that [21, 22, 22, 20.5, 20.1]
in ugriz.
The stored data (with their associated types) are listed below.
Basic SDSS object quantities
- RUN (LONG)
- RERUN (STRING)
- CAMCOL (LONG)
- FIELD (LONG)
- ID (LONG)
- OBJC_TYPE (LONG)
- OBJC_FLAGS (LONG) : Note that the 64 bit SDSS OBJC_FLAGS is split into two
- OBJC_FLAGS2 (LONG)
- COLC (FLOAT[5])
- FLAGS (LONG[5])
- FLAGS2 (LONG[5])
- RA (DOUBLE)
- DEC (DOUBLE)
SDSS Photometric quantities
- PSFFLUX (FLOAT[5]) : nmgy
- PSFFLUX_IVAR (FLOAT[5]) : Inverse variance (ivar) in 1./nmgy^2
- MODELFLUX (FLOAT[5]) : nmgy
- MODELFLUX_IVAR (FLOAT[5]) : 1./nmgy^2
- FIBERFLUX (FLOAT[5]) : nmgy
- PETROFLUX (FLOAT[5]) : nmgy
- PETROFLUX_IVAR (FLOAT[5]) : Inverse variance (ivar) in 1./nmgy^2
- DEVFLUX (FLOAT[5]) : nmgy
- DEVFLUX_IVAR (FLOAT[5]) : Inverse variance (ivar) in 1./nmgy^2
- EXPFLUX (FLOAT[5]) : nmgy
- EXPFLUX_IVAR (FLOAT[5]) : Inverse variance (ivar) in 1./nmgy^2
- APERFLUX (FLOAT[8,5]) : Aperture flux in first 8 SDSS apertures, nmgy
- EXTINCTION (FLOAT[5])
- STAR_LNL (FLOAT[5])
- EXP_LNL (FLOAT[5])
- DEV_LNL (FLOAT[5])
- FRACPSF (FLOAT[5])
- PETROR50 (FLOAT[5]) : In pixels
- PETROR90 (FLOAT[5]) : In pixels
- R_DEV (FLOAT[5]) : In pixels
- R_EXP (FLOAT[5]) : In pixels
Image, resolve and calibration quantities
- PSP_STATUS (LONG[5])
- PSF_FWHM (FLOAT[5]) : In arcsec
- RESOLVE_STATUS (INT) : Resolve status (see resolve data model)
- THING_ID (LONG) : ID of thing (see resolve data model)
- IFIELD (LONG) : Field object is in (see resolve data model)
- BALKAN_ID (LONG) : Balkan object is in (see resolve data model)
- NDETECT (INT) : The number of detections of the object in the SDSS imaging (see resolve data model)
- CALIB_STATUS (INT[5]) : Ubercalibration status (see ubercalibration data model)
- NMGYPERCOUNT (FLOAT[5]) : Calibrations
Data Sweep Sky Data Model
Only contains PHOTO-identified sky objects.
The stored data (with their associated types) are listed
below. Where the data differ from the standard SDSS data model, we
include a brief description.
Basic SDSS object quantities
- RUN (LONG)
- RERUN (STRING)
- CAMCOL (LONG)
- FIELD (LONG)
- ID (LONG)
- OBJC_TYPE (LONG)
- OBJC_FLAGS (LONG) : Note that the 64 bit SDSS OBJC_FLAGS is split into two
- OBJC_FLAGS2 (LONG)
- OBJC_ROWC (FLOAT)
- COLC (FLOAT[5])
- FLAGS (LONG[5])
- FLAGS2 (LONG[5])
- RA (DOUBLE)
- DEC (DOUBLE)
SDSS Photometric quantities
Image, resolve and calibration quantities
- PSP_STATUS (LONG[5])
- PSF_FWHM (FLOAT[5]) : In arcsec
- RESOLVE_STATUS (INT) : Resolve status (see resolve data model)
- THING_ID (LONG) : ID of thing (see resolve data model)
- IFIELD (LONG) : Field object is in (see resolve data model)
- BALKAN_ID (LONG) : Balkan object is in (see resolve data model)
- NDETECT (INT) : The number of detections of the object in the SDSS imaging (see resolve data model)
- CALIB_STATUS (INT[5]) : Ubercalibration status (see ubercalibration data model)
- NMGYPERCOUNT (FLOAT[5]) : Calibrations