Discovery of a Protocluster Associated with a Ly α Blob Pair at z = 2.3
Bright Ly alpha blobs (LABs)-extended nebulae with sizes of similar to 100 kpc and Ly alpha luminosities of similar to 10(44) erg s(-1)-often reside in overdensities of compact Ly alpha emitters (LAEs) that may be galaxy protoclusters. The number density, variance, and internal kinematics of LABs su...
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ndltd-arizona.edu-oai-arizona.openrepository.com-10150-6257752017-10-05T03:00:27Z Discovery of a Protocluster Associated with a Ly α Blob Pair at z = 2.3 Bădescu, Toma Yang, Yujin Bertoldi, Frank Zabludoff, Ann Karim, Alexander Magnelli, Benjamin Univ Arizona, Steward Observ galaxies: clusters: general galaxies: formation galaxies: high-redshift intergalactic medium large-scale structure of universe Bright Ly alpha blobs (LABs)-extended nebulae with sizes of similar to 100 kpc and Ly alpha luminosities of similar to 10(44) erg s(-1)-often reside in overdensities of compact Ly alpha emitters (LAEs) that may be galaxy protoclusters. The number density, variance, and internal kinematics of LABs suggest that they themselves trace group-like halos. Here, we test this hierarchical picture, presenting deep, wide-field Ly alpha narrowband imaging of a 1 degrees x. 0 degrees.5 region around a LAB pair at z = 2.3 discovered previously by a blind survey. We find 183 Lya emitters, including the original LAB pair and three new LABs with Ly alpha luminosities of (0.9-1.3) x 10(43) erg s(-1) and isophotal areas of 16-24 arcsec2. Using the LAEs as tracers and a new kernel density estimation method, we discover a large-scale overdensity (Bootes J1430+3522) with a surface density contrast of delta(Sigma) = 2.7, a volume density contrast of delta similar to 10.4, and a projected diameter of approximate to 20 comoving Mpc. Comparing with cosmological simulations, we conclude that this LAE overdensity will evolve into a present-day Coma-like cluster with log(M/M-circle dot) similar to 15.1 +/- 0.2. In this and three other wide-field LAE surveys re-analyzed here, the extents and peak amplitudes of the largest LAE overdensities are similar, not increasing with survey size, and implying that they were indeed the largest structures then and today evolve into rich clusters. Intriguingly, LABs favor the outskirts of the densest LAE concentrations, i.e., intermediate LAE overdensities of delta(Sigma) = 1-2. We speculate that these LABs mark infalling protogroups being accreted by the more massive protocluster. 2017-08-23 Article Discovery of a Protocluster Associated with a Ly α Blob Pair at z = 2.3 2017, 845 (2):172 The Astrophysical Journal 1538-4357 10.3847/1538-4357/aa8220 http://hdl.handle.net/10150/625775 http://arizona.openrepository.com/arizona/handle/10150/625775 The Astrophysical Journal en http://stacks.iop.org/0004-637X/845/i=2/a=172?key=crossref.8e2309e4aee1d5a33461c69905a9669a © 2017. The American Astronomical Society. All rights reserved. IOP PUBLISHING LTD |
collection |
NDLTD |
language |
en |
sources |
NDLTD |
topic |
galaxies: clusters: general galaxies: formation galaxies: high-redshift intergalactic medium large-scale structure of universe |
spellingShingle |
galaxies: clusters: general galaxies: formation galaxies: high-redshift intergalactic medium large-scale structure of universe Bădescu, Toma Yang, Yujin Bertoldi, Frank Zabludoff, Ann Karim, Alexander Magnelli, Benjamin Discovery of a Protocluster Associated with a Ly α Blob Pair at z = 2.3 |
description |
Bright Ly alpha blobs (LABs)-extended nebulae with sizes of similar to 100 kpc and Ly alpha luminosities of similar to 10(44) erg s(-1)-often reside in overdensities of compact Ly alpha emitters (LAEs) that may be galaxy protoclusters. The number density, variance, and internal kinematics of LABs suggest that they themselves trace group-like halos. Here, we test this hierarchical picture, presenting deep, wide-field Ly alpha narrowband imaging of a 1 degrees x. 0 degrees.5 region around a LAB pair at z = 2.3 discovered previously by a blind survey. We find 183 Lya emitters, including the original LAB pair and three new LABs with Ly alpha luminosities of (0.9-1.3) x 10(43) erg s(-1) and isophotal areas of 16-24 arcsec2. Using the LAEs as tracers and a new kernel density estimation method, we discover a large-scale overdensity (Bootes J1430+3522) with a surface density contrast of delta(Sigma) = 2.7, a volume density contrast of delta similar to 10.4, and a projected diameter of approximate to 20 comoving Mpc. Comparing with cosmological simulations, we conclude that this LAE overdensity will evolve into a present-day Coma-like cluster with log(M/M-circle dot) similar to 15.1 +/- 0.2. In this and three other wide-field LAE surveys re-analyzed here, the extents and peak amplitudes of the largest LAE overdensities are similar, not increasing with survey size, and implying that they were indeed the largest structures then and today evolve into rich clusters. Intriguingly, LABs favor the outskirts of the densest LAE concentrations, i.e., intermediate LAE overdensities of delta(Sigma) = 1-2. We speculate that these LABs mark infalling protogroups being accreted by the more massive protocluster. |
author2 |
Univ Arizona, Steward Observ |
author_facet |
Univ Arizona, Steward Observ Bădescu, Toma Yang, Yujin Bertoldi, Frank Zabludoff, Ann Karim, Alexander Magnelli, Benjamin |
author |
Bădescu, Toma Yang, Yujin Bertoldi, Frank Zabludoff, Ann Karim, Alexander Magnelli, Benjamin |
author_sort |
Bădescu, Toma |
title |
Discovery of a Protocluster Associated with a Ly α Blob Pair at z = 2.3 |
title_short |
Discovery of a Protocluster Associated with a Ly α Blob Pair at z = 2.3 |
title_full |
Discovery of a Protocluster Associated with a Ly α Blob Pair at z = 2.3 |
title_fullStr |
Discovery of a Protocluster Associated with a Ly α Blob Pair at z = 2.3 |
title_full_unstemmed |
Discovery of a Protocluster Associated with a Ly α Blob Pair at z = 2.3 |
title_sort |
discovery of a protocluster associated with a ly α blob pair at z = 2.3 |
publisher |
IOP PUBLISHING LTD |
publishDate |
2017 |
url |
http://hdl.handle.net/10150/625775 http://arizona.openrepository.com/arizona/handle/10150/625775 |
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