The 2dF-SDSS LRG and QSO (2SLAQ) website

Welcome to the 2dF-SDSS LRG and QSO (2SLAQ) website, which is the central location for information and updates on the 2SLAQ survey. This survey is now done collecting data and is being analysed by an international team of astronomers from the UK, Australian and the US.

LRG catalogue now queryable

Click here to query the 2SLAQ LRG catalogue.

Previous Updates


We release here the complete 2SLAQ QSO catalog data from Croom et al. (2008; in press).

2SLAQ Early Data Release (July 2005)

We present here the early data release (EDR) of the 2dF-SDSS LRG and QSO (2SLAQ) survey. These data include all observed 2SLAQ objects in 2003.

These data are released by the 2SLAQ team under the caveat that we have not finished our final data analysis and we have not performed a careful data-checking exercise on these data. We have also not studied the areal mask of these data in detail and have arbitarily removed some objects. We ask you to bare this in mind when using these datasets, especially for statistical analyses. We have primarily released this early data to help the community find interesting objects at high redshift for further individual follow-up observations.

Download data below (ascii files with headers)

  • 2SLAQ QUASAR DATA (see associated Croom et al. 2004 paper for details of quality flags)
    Photo-z Catalogs (July 2006)

    The 2SLAQ data has been used for two photo-z catalogs, see papers by Padmanabhan et al. (2004), Blake et al. (2006) and Collister et al. (2006)

    The latter two papers use a photo-z catalog called MegaZLRG which is now public to everyone from the link below.

  • readme_megazlrg
    2SLAQ LRG Papers (July 2006)

    On July 31st 2006, three 2SLAQ papers appeared on astro-ph present details of the 2SLAQ LRG sample and new results. These papers are:

  • Cannon et al. ( astro-ph/0607631 ) which is accepted for publication in MNRAS and releases the data to the public when the paper appears in the journal (offical reference is now MNRAS, 2006, 372, 425). See a higher resolution version of the paper here
  • Wake et al. ( astro-ph/0607629 ) which is accepted for publication in MNRAS and discusses the evolution of the luminosity function.
  • Collister et al. ( astro-ph/0607630 ) which is submitted to MNRAS and discusses the MegaZLRG photo-z catalog (see above) .
    2SLAQ Data now VO-compliant!

    Gordon Richards (JHU, Drexel) has made an OpenSkyNode for the 2SLAQ data. This allows easy access to the data and trivial cross-matching with many other datasets. See:

    2SLAQ Paper by Roseboom et al. (Sept 2006)

    Another science paper by Roseboom et al. on the The Star Formation Histories of Luminous Red Galaxies , see astroph/0609178

    The data used in this paper can be found at the UQ 2SLAQ website


    We present here the full 2SLAQ LRG sample from Cannon et al. (2006, MNRAS, 372, 425) which is now available for public use.

    Radio Galaxies in 2SLAQ (Dec 2006)

    Sadler et al. present a joint analysis of the 2SLAQ LRGs and FIRST and NVSS radio surveys. They find "The evolution seen in the low-power radio-galaxy population implies that the total energy input into massive early-type galaxies from AGN heating increases with redshift, and was roughly 50% higher at z~0.55 (and up to a factor of two higher at z~1) than in the local universe."

    Conference Proceeding (Dec 2006)

    We present here our submission to the conference "Heating vs. Cooling in Galaxies and Clusters of Galaxies" (August 2006, Garching, Germany). Paper is entitled "2dF-SDSS LRG and QSO (2SLAQ) Survey: Evolution of the Most Massive Galaxies"

    Two More Science Papers! (Dec 2006)

    The clustering of 2SLAQ LRGs and quasars was presented by Ross et al. (astro-ph/0612400) and de Angela et al. (astro-ph/0612401) respectively.

    SDSS-III follows 2SLAQ, but will be much bigger!

    The SDSS-III project ( is planning the Baryon Oscillation Spectroscopic Survey (BOSS) which mimics the 2SLAQ LRG selection. However, BOSS will cover 50 times more area (10,000 sq degs) and take nearly 6 years to complete, using the SDSS infrastructure. The 2SLAQ data was seen as an important pathfinder for such a survey and will help in the planning of SDSS-III.

    Update on Science Papers (April 2008)

    The 2SLAQ samples continue to deliver important new science:

  • Hirata et al. (2007) discussed the intrinsic galaxy alignments of 2SLAQ LRGs and their implications for weak lensing surveys.
  • Johnston et al. (2008) present an anaylsis of radio quiet and radio loud LRGs using 2SLAQ data.
  • Almeida et al. (2007) discuss LRG evolution in the context of semi-analytical models.
  • Wake et al. (2008) present an analysis of the LRG correlation function as a function of redshift (using 2SLAQ and SDSS), constraining the Halo Occupation Distribution (HOD) using the data.
    Public Release of 2SLAQ QSO line data

    We release here the measured QSO MgII line width parameters used in the 2SLAQ paper by Fine et al. (2008) . Columns include name, redshift, magnitude, line width of MgII, error on line width, and survey observed (2QZ, SDSS, 2SLAQ).

    Another Science Paper (Oct 2008)

    Wake et al . (2008) continue their study of the clustering of 2SLAQ LRGs, but this time focusing on radio galaxies.

    Related 2SLAQ Links

  • Univ. of Queensland 2SLAQ page

  • Durham 2SLAQ page

  • Univ. of Illinois 2SLAQ page

  • Peter Weilbacher's 2SLAQ page