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The Origin and Evolution of Lyα Blobs in Cosmological Galaxy Formation Simulations

Kimock, Benjamin and Narayanan, Desika and Smith, Aaron and Ma, Xiangcheng and Feldmann, Robert and Anglés-Alcázar, Daniel and Bromm, Volker and Davé, Romeel and Geach, James E. and Hopkins, Philip and Keres̆, Dus̆an (2021) The Origin and Evolution of Lyα Blobs in Cosmological Galaxy Formation Simulations. Astrophysical Journal, 909 (2). Art. No. 119. ISSN 0004-637X. doi:10.3847/1538-4357/abbe89.

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High-redshift Lyα blobs (LABs) are an enigmatic class of objects that have been the subject of numerous observational and theoretical investigations. It is of particular interest to determine the dominant power sources for their luminosity, as direct emission from H ii regions, cooling gas, and fluorescence due to the presence of active galactic nuclei (AGNs) can all contribute significantly. In this paper, we present the first theoretical model to consider all of these physical processes in an attempt to develop a model for the origin of LABs. This is achieved by combining a series of high-resolution cosmological zoom-in simulations with ionization and Lyα radiative transfer models. We find that massive galaxies display a range of Lyα luminosities and spatial extents (which strongly depend on the limiting surface brightness used) over the course of their lives, though regularly exhibit luminosities and sizes consistent with observed LABs. The model LABs are typically powered from a combination of recombination in star-forming galaxies, as well as cooling emission from gas associated with accretion. When AGNs are included in the model, the fluorescence caused by active galactic nucleus-driven ionization can be a significant contributor to the total Lyα luminosity as well. Within our modeled mass range, there are no obvious threshold physical properties that predict the appearance of LABs, and only weak correlations of the luminosity with the physical properties of the host galaxy. This is because the emergent Lyα luminosity from a system is a complex function of the gas temperature, ionization state, and Lyα escape fraction.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Kimock, Benjamin0000-0002-3160-7679
Narayanan, Desika0000-0002-7064-4309
Smith, Aaron0000-0002-2838-9033
Ma, Xiangcheng0000-0001-8091-2349
Feldmann, Robert0000-0002-1109-1919
Anglés-Alcázar, Daniel0000-0001-5769-4945
Bromm, Volker0000-0003-0212-2979
Davé, Romeel0000-0003-2842-9434
Geach, James E.0000-0003-4964-4635
Hopkins, Philip0000-0003-3729-1684
Keres̆, Dus̆an0000-0002-1666-7067
Alternate Title:The Origin and Evolution of Lyman-alpha Blobs in Cosmological Galaxy Formation Simulations
Additional Information:© 2021. The American Astronomical Society. Received 2020 April 17; revised 2020 September 29; accepted 2020 October 4; published 2021 March 10. We thank the referee for constructive comments and suggestions that have improved the quality of this work. We thank Claude-André Faucher-Giguère, Lluis Mas-Ribas, and George Privon for helpful conversations. D.N. acknowledges support from NSF-1909153. A.S. acknowledges support from program number HST-HF2-51421.001-A provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. R.F. acknowledges financial support from the Swiss National Science Foundation (grant No. 157591). The simulations were run using XSEDE (TG-AST160048), supported by NSF grant ACI-1053575, Northwestern University's compute cluster "Quest," and on the University of Florida HiPerGator computing cluster. The data used in this work were, in part, hosted on facilities supported by the Scientific Computing Core at the Flatiron Institute, a division of the Simons Foundation. This work was initiated or performed in part at the Aspen Center for Physics, which is supported by NSF grant PHY-1607611.
Group:Astronomy Department, TAPIR
Funding AgencyGrant Number
NASA Hubble FellowshipHST-HF2-51421.001-A
Swiss National Science Foundation (SNSF)157591
Simons FoundationUNSPECIFIED
Subject Keywords:Galaxies; Galaxy formation; Radiative transfer simulations
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Galaxies (573); Galaxy formation (595); Radiative transfer simulations (1967)
Record Number:CaltechAUTHORS:20210311-091942314
Persistent URL:
Official Citation:Benjamin Kimock et al 2021 ApJ 909 119
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108393
Deposited By: Tony Diaz
Deposited On:12 Mar 2021 18:55
Last Modified:16 Nov 2021 19:11

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