Monthly Notices of the Royal Astronomical Society (Monthly Notices of the Royal Astronomical Society)

THE ROYAL ASTRONOMICAL SOCIETY (THE ROYAL ASTRONOMICAL SOCIETY)
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Statistics of two-point correlation and network topology for Ly α emitters at z ≈ 2.67

  • Sungryong Hong (Department of Astronomy, The University of Texas at Austin) ;
  • Arjun Dey (National Optical Astronomy Observatory) ;
  • Kyoung-Soo Lee (Department of Physics and Astronomy, Purdue University) ;
  • Alvaro A Orsi (Centro de Estudios de Fisica del Cosmos de Aragon) ;
  • Karl Gebhardt (Department of Astronomy, The University of Texas at Austin) ;
  • Mark Vogelsberger (Department of Physics, Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology) ;
  • Lars Hernquist (Harvard-Smithsonian Center for Astrophysics) ;
  • Rui Xue (Department of Physics and Astronomy, Purdue University) ;
  • Intae Jung (Department of Astronomy, The University of Texas at Austin) ;
  • Steven L Finklestein (Department of Astronomy, The University of Texas at Austin) ;
  • Sarah Tuttle (Department of Astronomy, University of Washington) ;
  • Michael Boylan-Kolchin (Department of Astronomy, The University of Texas at Austin)
  • Received : 2018.05.01
  • Accepted : 2018.11.19
  • Published : 20190300
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Abstract

We investigate the spatial distribution of Ly α-emitting galaxies (LAEs) at z ≈ 2.67, selected from the NOAO Deep Wide-Field Survey, using two-point statistics and topological diagnostics adopted from network science. We measure the clustering length, r0 ≈ 4 h-1 Mpc, and the bias, bLAE = 2.2+0.2-0.1. Fitting the clustering with halo occupation distribution (HOD) models results in two disparate possibilities: (1) where the fraction of central galaxies is <1 per cent in haloes of mass >1012 M⊙ and (2) where the fraction is ≈20 per cent. We refer to these two scenarios as the 'Dusty Core Scenario' for Model#1, since most of the central galaxies in massive haloes are dead in Ly α emission, and the 'Pristine Core Scenario' for Model#2, since the central galaxies are bright in Ly α emission. Traditional two-point statistics cannot distinguish between these disparate models given the current data sets. To overcome this degeneracy, we generate mock catalogues for each HOD model using a high-resolution N-body simulation and adopt a network statistics approach, which provides excellent topological diagnostics for galaxy point distributions. We find three topological anomalies from the spatial distribution of observed LAEs, which are not reproduced by the HOD mocks. We find that Model#2 matches better all network statistics than Model#1, suggesting that the central galaxies in >1012 h-1 M⊙ haloes at z ≈ 2.67 need to be less dusty to be bright as LAEs, potentially implying some replenishing channels of pristine gas such as the cold mode accretion.

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Acknowledgement

We are grateful to the anonymous referee for comments that have improved this paper. SH's research activities have been supported by the University of Texas at Austin and Korea Institute for Advanced Study. Based in part on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. The observations reported here were obtained in part at the MMT Observatory, a facility operated jointly by the Smithsonian Institution and the University of Arizona. Some of the MMT telescope time was granted by NOAO, through the Telescope System Instrumentation Program (TSIP). TSIP is funded by NSF. AD's research is supported by the National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA) under cooperative agreement with the National Science Foundation. This research was also supported in part by NASA HST-GO-13000.