Redshifts, Sample Purity, and BCG Positions for the Galaxy Cluster Catalog from the First 720 Square Degrees of the South Pole Telescope Survey
We present the results of the ground- and space-based optical and near-infrared (NIR) follow-up of 224 galaxy cluster candidates detected with the Sunyaev-Zel'dovich (SZ) effect in the 720 deg^2 of the South Pole Telescope (SPT) survey completed in the 2008 and 2009 observing seasons. We use th...
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ftcaltechauth:oai:authors.library.caltech.edu:36228 2023-05-15T18:22:13+02:00 Redshifts, Sample Purity, and BCG Positions for the Galaxy Cluster Catalog from the First 720 Square Degrees of the South Pole Telescope Survey Song, J. Lueker, M. Padin, S. Shirokoff, E. Vieira, J. D. 2012-12-10 application/pdf https://authors.library.caltech.edu/36228/ https://authors.library.caltech.edu/36228/1/0004-637X_761_1_22.pdf https://resolver.caltech.edu/CaltechAUTHORS:20130108-091715280 en eng American Astronomical Society https://authors.library.caltech.edu/36228/1/0004-637X_761_1_22.pdf Song, J. and Lueker, M. and Padin, S. and Shirokoff, E. and Vieira, J. D. (2012) Redshifts, Sample Purity, and BCG Positions for the Galaxy Cluster Catalog from the First 720 Square Degrees of the South Pole Telescope Survey. Astrophysical Journal, 761 (1). Art. No. 22. ISSN 0004-637X. doi:10.1088/0004-637X/761/1/22. https://resolver.caltech.edu/CaltechAUTHORS:20130108-091715280 <https://resolver.caltech.edu/CaltechAUTHORS:20130108-091715280> other Article PeerReviewed 2012 ftcaltechauth https://doi.org/10.1088/0004-637X/761/1/22 2021-11-11T18:52:27Z We present the results of the ground- and space-based optical and near-infrared (NIR) follow-up of 224 galaxy cluster candidates detected with the Sunyaev-Zel'dovich (SZ) effect in the 720 deg^2 of the South Pole Telescope (SPT) survey completed in the 2008 and 2009 observing seasons. We use the optical/NIR data to establish whether each candidate is associated with an overdensity of galaxies and to estimate the cluster redshift. Most photometric redshifts are derived through a combination of three different cluster redshift estimators using red-sequence galaxies, resulting in an accuracy of Δz/(1 + z) = 0.017, determined through comparison with a subsample of 57 clusters for which we have spectroscopic redshifts. We successfully measure redshifts for 158 systems and present redshift lower limits for the remaining candidates. The redshift distribution of the confirmed clusters extends to z = 1.35 with a median of z_(med) = 0.57. Approximately 18% of the sample with measured redshifts lies at z > 0.8. We estimate a lower limit to the purity of this SPT SZ-selected sample by assuming that all unconfirmed clusters are noise fluctuations in the SPT data. We show that the cumulative purity at detection significance ξ > 5(ξ > 4.5) is ≥95% (≥70%). We present the red brightest cluster galaxy (rBCG) positions for the sample and examine the offsets between the SPT candidate position and the rBCG. The radial distribution of offsets is similar to that seen in X-ray-selected cluster samples, providing no evidence that SZ-selected cluster samples include a different fraction of recent mergers from X-ray-selected cluster samples. Article in Journal/Newspaper South pole Caltech Authors (California Institute of Technology) South Pole The Astrophysical Journal 761 1 22 |
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Caltech Authors (California Institute of Technology) |
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English |
description |
We present the results of the ground- and space-based optical and near-infrared (NIR) follow-up of 224 galaxy cluster candidates detected with the Sunyaev-Zel'dovich (SZ) effect in the 720 deg^2 of the South Pole Telescope (SPT) survey completed in the 2008 and 2009 observing seasons. We use the optical/NIR data to establish whether each candidate is associated with an overdensity of galaxies and to estimate the cluster redshift. Most photometric redshifts are derived through a combination of three different cluster redshift estimators using red-sequence galaxies, resulting in an accuracy of Δz/(1 + z) = 0.017, determined through comparison with a subsample of 57 clusters for which we have spectroscopic redshifts. We successfully measure redshifts for 158 systems and present redshift lower limits for the remaining candidates. The redshift distribution of the confirmed clusters extends to z = 1.35 with a median of z_(med) = 0.57. Approximately 18% of the sample with measured redshifts lies at z > 0.8. We estimate a lower limit to the purity of this SPT SZ-selected sample by assuming that all unconfirmed clusters are noise fluctuations in the SPT data. We show that the cumulative purity at detection significance ξ > 5(ξ > 4.5) is ≥95% (≥70%). We present the red brightest cluster galaxy (rBCG) positions for the sample and examine the offsets between the SPT candidate position and the rBCG. The radial distribution of offsets is similar to that seen in X-ray-selected cluster samples, providing no evidence that SZ-selected cluster samples include a different fraction of recent mergers from X-ray-selected cluster samples. |
format |
Article in Journal/Newspaper |
author |
Song, J. Lueker, M. Padin, S. Shirokoff, E. Vieira, J. D. |
spellingShingle |
Song, J. Lueker, M. Padin, S. Shirokoff, E. Vieira, J. D. Redshifts, Sample Purity, and BCG Positions for the Galaxy Cluster Catalog from the First 720 Square Degrees of the South Pole Telescope Survey |
author_facet |
Song, J. Lueker, M. Padin, S. Shirokoff, E. Vieira, J. D. |
author_sort |
Song, J. |
title |
Redshifts, Sample Purity, and BCG Positions for the Galaxy Cluster Catalog from the First 720 Square Degrees of the South Pole Telescope Survey |
title_short |
Redshifts, Sample Purity, and BCG Positions for the Galaxy Cluster Catalog from the First 720 Square Degrees of the South Pole Telescope Survey |
title_full |
Redshifts, Sample Purity, and BCG Positions for the Galaxy Cluster Catalog from the First 720 Square Degrees of the South Pole Telescope Survey |
title_fullStr |
Redshifts, Sample Purity, and BCG Positions for the Galaxy Cluster Catalog from the First 720 Square Degrees of the South Pole Telescope Survey |
title_full_unstemmed |
Redshifts, Sample Purity, and BCG Positions for the Galaxy Cluster Catalog from the First 720 Square Degrees of the South Pole Telescope Survey |
title_sort |
redshifts, sample purity, and bcg positions for the galaxy cluster catalog from the first 720 square degrees of the south pole telescope survey |
publisher |
American Astronomical Society |
publishDate |
2012 |
url |
https://authors.library.caltech.edu/36228/ https://authors.library.caltech.edu/36228/1/0004-637X_761_1_22.pdf https://resolver.caltech.edu/CaltechAUTHORS:20130108-091715280 |
geographic |
South Pole |
geographic_facet |
South Pole |
genre |
South pole |
genre_facet |
South pole |
op_relation |
https://authors.library.caltech.edu/36228/1/0004-637X_761_1_22.pdf Song, J. and Lueker, M. and Padin, S. and Shirokoff, E. and Vieira, J. D. (2012) Redshifts, Sample Purity, and BCG Positions for the Galaxy Cluster Catalog from the First 720 Square Degrees of the South Pole Telescope Survey. Astrophysical Journal, 761 (1). Art. No. 22. ISSN 0004-637X. doi:10.1088/0004-637X/761/1/22. https://resolver.caltech.edu/CaltechAUTHORS:20130108-091715280 <https://resolver.caltech.edu/CaltechAUTHORS:20130108-091715280> |
op_rights |
other |
op_doi |
https://doi.org/10.1088/0004-637X/761/1/22 |
container_title |
The Astrophysical Journal |
container_volume |
761 |
container_issue |
1 |
container_start_page |
22 |
_version_ |
1766201596406923264 |