Oral Presentation
Cosmic Himalayas: The Most Concentrated Quasars at Cosmic Noon
Presenter: Yongming Liang (ICRR, U. Tokyo)
Discovered by the MAMMOTH-Subaru survey in BOSSJ0210, the Cosmic Himalayas is an extraordinary structure hosting 11 SDSS/eBOSS luminous (L_bol≳10^46 erg s^-1) Type-1 quasars at z=2.2, within a compact (40 cMpc)^3 region. This structure represents the most significant quasar density peak at z>2, being 30 times the average with a remarkable 17σ significance. Mapped by Subaru/HSC NB387 for z=2.2 Lyman-alpha emitters (LAEs), the quasar overdensity intriguingly does not match LAE overdensities but lies perpendicular to a ~100 cMpc large-scale filament. This filament's nodes showcase distinct galaxy properties, such as varied star-formation rates, AGN hosting probabilities, and extended Lyman-alpha emission detection, with quasars positioned at intermediate points. Initial insights from 3D intergalactic medium (IGM) tomography, created using SDSS/eBOSS background quasars, indicate a significant ionizing stage difference between the filament's nodes, suggesting quasars play a central role in shaping the ionizing topology. These findings highlight the Cosmic Himalayas as a unique structure for advancing our understanding of the interplay between quasars, galaxies, and the IGM.
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