_version_ 1866910884781096960
author Liang, Yongming
Ouchi, Masami
Sun, Dongsheng
Kashikawa, Nobunari
Cai, Zheng
Cantalupo, Sebastiano
Nagamine, Kentaro
Yajima, Hidenobu
Kirihara, Takanobu
Zhang, Haibin
Li, Mingyu
Shimakawa, Rhythm
Fan, Xiaohui
Ito, Kei
Tanaka, Masayuki
Harikane, Yuichi
Prochaska, J. Xavier
Travascio, Andrea
Wang, Weichen
Elvis, Martin
Fabbiano, Giuseppina
Arita, Junya
Onoue, Masafusa
Silverman, John D.
Shi, Dong Dong
An, Fangxia
Izumi, Takuma
Shimasaku, Kazuhiro
Uchiyama, Hisakazu
Zhu, Chenghao
author_facet Liang, Yongming
Ouchi, Masami
Sun, Dongsheng
Kashikawa, Nobunari
Cai, Zheng
Cantalupo, Sebastiano
Nagamine, Kentaro
Yajima, Hidenobu
Kirihara, Takanobu
Zhang, Haibin
Li, Mingyu
Shimakawa, Rhythm
Fan, Xiaohui
Ito, Kei
Tanaka, Masayuki
Harikane, Yuichi
Prochaska, J. Xavier
Travascio, Andrea
Wang, Weichen
Elvis, Martin
Fabbiano, Giuseppina
Arita, Junya
Onoue, Masafusa
Silverman, John D.
Shi, Dong Dong
An, Fangxia
Izumi, Takuma
Shimasaku, Kazuhiro
Uchiyama, Hisakazu
Zhu, Chenghao
contents We report the identification of a quasar overdensity in the BOSSJ0210 field, dubbed Cosmic Himalayas, consisting of 11 quasars at $z=2.16-2.20$, the densest overdensity of quasars ($17σ$) in the $\sim$10,000 deg$^2$ of the Sloan Digital Sky Survey. We present the spatial distributions of galaxies and quasars and an HI absorption map of the intergalactic medium (IGM). On the map of 465 galaxies selected from the MAMMOTH-Subaru survey, we find two galaxy density peaks that do not fall on the quasar overdensity but instead exist at the northwest and southeast sides, approximately 25 $h^{-1}$ comoving-Mpc apart from the quasar overdensity. With a spatial resolution of 15 $h^{-1}$ comoving Mpc in projection, we produce a three-dimensional HI tomography map by the IGM Ly$α$ forest in the spectra of 23 SDSS/eBOSS quasars behind the quasar overdensity. Surprisingly, the quasar overdensity coincides with neither an absorption peak nor a transmission peak of IGM HI but lies near the border separating opaque and transparent volumes, with the more luminous quasars located in an environment with lesser IGM HI. Hence remarkably, the overdensity region traced by the 11 quasars, albeit all in coherently active states, has no clear coincidence with peaks of galaxies or HI absorption densities. Current physical scenarios with mixtures of HI overdensities and quasar photoionization cannot fully interpret the emergence of Cosmic Himalayas, suggesting this peculiar structure is an excellent laboratory to unveil the interplay between galaxies, quasars, and the IGM.
format Preprint
id arxiv_https___arxiv_org_abs_2404_15963
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Cosmic Himalayas: The Highest Quasar Density Peak Identified in a 10,000 deg$^2$ Sky with Spatial Discrepancies between Galaxies, Quasars, and IGM HI
Liang, Yongming
Ouchi, Masami
Sun, Dongsheng
Kashikawa, Nobunari
Cai, Zheng
Cantalupo, Sebastiano
Nagamine, Kentaro
Yajima, Hidenobu
Kirihara, Takanobu
Zhang, Haibin
Li, Mingyu
Shimakawa, Rhythm
Fan, Xiaohui
Ito, Kei
Tanaka, Masayuki
Harikane, Yuichi
Prochaska, J. Xavier
Travascio, Andrea
Wang, Weichen
Elvis, Martin
Fabbiano, Giuseppina
Arita, Junya
Onoue, Masafusa
Silverman, John D.
Shi, Dong Dong
An, Fangxia
Izumi, Takuma
Shimasaku, Kazuhiro
Uchiyama, Hisakazu
Zhu, Chenghao
Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
We report the identification of a quasar overdensity in the BOSSJ0210 field, dubbed Cosmic Himalayas, consisting of 11 quasars at $z=2.16-2.20$, the densest overdensity of quasars ($17σ$) in the $\sim$10,000 deg$^2$ of the Sloan Digital Sky Survey. We present the spatial distributions of galaxies and quasars and an HI absorption map of the intergalactic medium (IGM). On the map of 465 galaxies selected from the MAMMOTH-Subaru survey, we find two galaxy density peaks that do not fall on the quasar overdensity but instead exist at the northwest and southeast sides, approximately 25 $h^{-1}$ comoving-Mpc apart from the quasar overdensity. With a spatial resolution of 15 $h^{-1}$ comoving Mpc in projection, we produce a three-dimensional HI tomography map by the IGM Ly$α$ forest in the spectra of 23 SDSS/eBOSS quasars behind the quasar overdensity. Surprisingly, the quasar overdensity coincides with neither an absorption peak nor a transmission peak of IGM HI but lies near the border separating opaque and transparent volumes, with the more luminous quasars located in an environment with lesser IGM HI. Hence remarkably, the overdensity region traced by the 11 quasars, albeit all in coherently active states, has no clear coincidence with peaks of galaxies or HI absorption densities. Current physical scenarios with mixtures of HI overdensities and quasar photoionization cannot fully interpret the emergence of Cosmic Himalayas, suggesting this peculiar structure is an excellent laboratory to unveil the interplay between galaxies, quasars, and the IGM.
title Cosmic Himalayas: The Highest Quasar Density Peak Identified in a 10,000 deg$^2$ Sky with Spatial Discrepancies between Galaxies, Quasars, and IGM HI
topic Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2404.15963