Data model: xdqso_index

General description: This file provides a spatial index into the XDQSO results. Basically, it is a list of all of the SDSS fields with XDQSO quasars in them, along with the information about how to access the field. Thus, you can find a list of fields of interest using the RA and DEC values, then use the RUN value to find the appropriate file, which will be an xdcore file. Then IXDCORE is an index into that file for the first entry in the field, and NXDCORE is the total number of entries for the field (which are immediately after the first entry.

Naming convention: xdqso_index.fits

Approximate size: 10 Mbytes.

File type: FITS

Read by products: sas

Written by products: sas

Required column names:

• RUN (int16): SDSS drift scan run
• CAMCOL (int16): SDSS drift scan camcol
• FIELD (int16): SDSS drift scan field
• RA (float64): RA (J2000 deg) of field center
• DEC (float64): Dec (J2000 deg) of field center
• IXDCORE (int32): position in xdcore file of first entry for field
• NXDCORE (int32): number of QSO identified by XD in this field