ODIN: Where Do Lyα Blobs Live? Contextualizing Blob Environments within Large-scale Structure

Vandana Ramakrishnan, Byeongha Moon, Sang Hyeok Im, Rameen Farooq, Kyoung Soo Lee, Eric Gawiser, Yujin Yang, Changbom Park, Ho Seong Hwang, Francisco Valdes, Maria Celeste Artale, Robin Ciardullo, Arjun Dey, Caryl Gronwall, Lucia Guaita, Woong Seob Jeong, Nelson Padilla, Akriti Singh, Ann Zabludoff

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


While many Lyα blobs (LABs) are found in and around several well-known protoclusters at high redshift, how they trace the underlying large-scale structure is still poorly understood. In this work, we utilize 5352 Lyα emitters (LAEs) and 129 LABs at z = 3.1 identified over a ∼9.5 deg2 area in early data from the ongoing One-hundred-deg2 DECam Imaging in Narrowbands (ODIN) survey to investigate this question. Using LAEs as tracers of the underlying matter distribution, we identify overdense structures as galaxy groups, protoclusters, and filaments of the cosmic web. We find that LABs preferentially reside in regions of higher-than-average density and are located in closer proximity to overdense structures, which represent the sites of protoclusters and their substructures. Moreover, protoclusters hosting one or more LABs tend to have a higher descendant mass than those which do not. Blobs are also strongly associated with filaments of the cosmic web, with ∼70% of the population being within a projected distance of ∼2.4 pMpc from a filament. We show that the proximity of LABs to protoclusters is naturally explained by their association with filaments as large cosmic structures are where many filaments converge. The contiguous wide-field coverage of the ODIN survey allows us to establish firmly a connection between LABs as a population and filaments of the cosmic web for the first time.

Original languageEnglish
Article number119
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 1 Jul 2023

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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