Table Formats

ASCII Tables

These are plain-text versions of the data tables and can be read with any standard text viewer. Although convenient for browsing, our use of INDEF tags to flag nonexistent data will make this file less useful as input to other pieces of software. These files can be used as input to the Jeff Munn's CHART database progam in IRAF.

FITS Tables

These binary tables (also known as "BINTABLES") are ideal for using as input to data analysis software. For example, users of IDL can read in the GOODS-North compendium table and plot redshift (stored in the field called z) against the i-band magnitude (imag) as follows:

	catalog = mrdfits('goods-n-all.fits',1,header)
	z = catalog.z
	imag = catalog.imag
	good = where( imag lt 30 and z gt 0 )
	plot, imag[good], z[good], psym=4

In this case, catalog is an IDL structure that holds all of the data. In order to extract data from the structure you will need to know the names of the fields (essentially, the names of the columns), which are listed in these files:

You can also get this information using the IDL help command:

	IDL> help,catalog,/struct
	** Structure <393dc8>, 16 tags, length=72, data length=72, refs=1:
   	RA              DOUBLE           189.40813
   	DEC             DOUBLE           62.275272
   	BMAG            FLOAT           13.8700
   	VMAG            FLOAT           14.3500
   	IMAG            FLOAT           14.5900
   	ZMAG            FLOAT           13.9200
   	Z               FLOAT          -2.00000
   	ZFLAG           LONG                 0
   	Z_UHDMOS        FLOAT          -1.00000
   	Z_UHLRIS        FLOAT          -2.00000
   	Z_TKRS          FLOAT          -1.00000
   	Z_COHEN         FLOAT          -1.00000
   	Z_LICK          FLOAT          -1.00000
   	Z_DAWSON        FLOAT          -1.00000
   	Z_STEIDEL       FLOAT          -1.00000
   	Z_OTHER         FLOAT          -1.00000

Note that in addition to data fields, the FITS tables also include information in the FITS header providing information about the content, such as authors, references, etc. If the table was read in using the mrdfits command listed above, the FITS header can simply be printed out:

	IDL> print,header

STSDAS Tables

These binary tables are ideal for using within the IRAF environment. For example, IRAF users can plot redshift (stored in the column z) against the i-band magnitude (imag) using the IGI plotting program by as follows (after loading stsdas.graphics.stplot:

	data goods-n-all.tab
	xcolumn imag
	ycolumn z
	limits 14 26 0 5
	box
	ptype 4 0
	points
	xlabel i Magnitude
	ylabel Redshift

In order to extract data from the structure you will need to know the names of the fields (essentially, the names of the columns):

You can also use the IRAF tlcol command to get a listing of the available columns. As with the FITS tables, the STSDAS tables contain header information on the content which may be viewed using the tprint command:

	st> tprint goods-n-all.tab prpar+ prdat-

Description of Additional Files

DBFORMAT files (*.dbformat): These files describe the content of the ASCII tables and are used as input to the CHART database program in IRAF. Refer to the CHART help page for further information.
KEYS files (*.keys): These files define the available plots which can be made using the CHART database program in IRAF. Refer to the CHART help page for further information.