Overview Duplicates Matching to HST

Garching DR4 data

This set of pages contain the derived galaxy properties from the Garching emission line analysis. This is a (substantially) extended version of our previous release, not only in that the data are for the DR4 instead of the DR2, but in that much more information extracted from the spectra is included. In addition we include some files to aid matching of old and new catalogues and a list of duplicate observations as well as list of matches to HST observations.

The data we provide can be divided into two different categories, namely the raw and derived data. The derived data follow the same layout as described in the previous data release and the raw data are the quantities we measure from the spectra.

The data are described in detail on separate pages - one for the raw data and one for the derived data. This page gives a brief overview of what is where and what is included in this list. Cautions about the data are generally given on the data pages. A total of 567486 galaxy spectra are included in our list, 520082 of these are unique using the definition given below.


04/04/07: Added stellar metallicities, ages and stellar mass estimates from Gallazzi et al.

Which plates are included?

The full list of PLATEID and MJD can be found here. And the Yanny format file used for the reduction can be found here

The organisation of the data

The files with raw data define the order of the objects and are FITS tables that are sorted with the same number of elements. These files contain the line fluxes, equivalent widths and continuum indices as well as information about the objects such as their redshifts, velocity dispersions and plate, fiber and MJD. While these files can be read in directly using mrdfits in IDL, this is not recommended as some of the files are very big. Use other approaches instead.

Go to the raw data

In addition to these large FITS tables with raw measurements from the spectra, we also have files with derived data - this include gas-phase metallicity estimates, star formation rates, stellar masses and the These files either correspond one-to-one with the raw files, or there is a lookup file associated to the data which can be used to correlate the two.


The sample included here has a lot of duplicates - this is very useful for assessing the true uncertainties in measured quantities, see in particular the discussion about uncertainty estimates here. However it is necessary to know which objects are duplicates of each other for analysis of course. This is achived with these files:

Thus to make a histogram of the redshifts of the sample excluding duplicates you can do the following (assuming the redshift is already read in from the FITS tabels to a variable z ):

IDL> rdfloat, 'parsed_duplicates150.txt', index, flag
IDL> autohist, z[where(flag eq 1)]


perldl> ($flag) = rcols 'parsed_duplicates150.txt.gz', 1
perldl> bin hist $z->where($flag == 1)

You can get PDL at http://pdl.perl.org.

Other lookup files

We also provide the following files for convenience:

To make sure that the id_* files are understood, here is how to compare the Ha values from our DR2 release with that from the DR4 release (again the reading is suppressed):

  IDL> rdfloat, 'id_of_dr2_in_dr4.list', ind
  IDL> ok=where(ind ge 0)
  IDL> plot, ha_dr4[ind[ok]], ha_dr2[ok], psym=3


perldl> ($ind) = rcols 'id_of_dr2_in_dr4.list'
perldl> $ok=which($ind >= 0)
perldl> points $ha_dr4($ind($ok)), $ha_dr2($ok), {Symbol => -2}

Matching to HST Archive

MAST - STScI's archive facility - provides a list of the HST exposures on-line. For conveniece we have matched this to the positions of our sample as well as the full DR4 imaging data using the Footprint server. click here to get more information.

Note about previous version (relevant only for SDSS members)

For those that used the first incarnation of these files, a note of caution is necessary: The current version includes all plates in the DR4 released to the public and as such is different from the previous data-release we made. A file containing the reverse lookup between the current files (line number) and the ID in the previous release (first column) can be found here.

Jarle Brinchmann
Last modified: Mon Jan 3 12:49:28 WET 2005