A Caltech Library Service

ALMA Observations of Lyα Blob 1: Halo Substructure Illuminated from Within

Geach, J. E. and Steidel, C. C. (2016) ALMA Observations of Lyα Blob 1: Halo Substructure Illuminated from Within. Astrophysical Journal, 832 (1). Art. No. 37. ISSN 0004-637X. doi:10.3847/0004-637X/832/1/37.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Submitted Version
See Usage Policy.


Use this Persistent URL to link to this item:


We present new Atacama Large Millimeter/Submillimeter Array (ALMA) 850 μm continuum observations of the original Lyα Blob (LAB) in the SSA22 field at z = 3.1 (SSA22-LAB01). The ALMA map resolves the previously identified submillimeter source into three components with a total flux density of S_(850) = 1.68 ± 0.06 mJy, corresponding to a star-formation rate of ~150 M ⊙ yr^(−1). The submillimeter sources are associated with several faint (m ≈ 27 mag) rest-frame ultraviolet sources identified in Hubble Space Telescope Imaging Spectrograph (STIS) clear filter imaging (λ ≈ 5850 Å). One of these companions is spectroscopically confirmed with the Keck Multi-Object Spectrometer For Infra-Red Exploration to lie within 20 projected kpc and 250 km s^(−1) of one of the ALMA components. We postulate that some of these STIS sources represent a population of low-mass star-forming satellites surrounding the central submillimeter sources, potentially contributing to their growth and activity through accretion. Using a high-resolution cosmological zoom simulation of a 10^(13) M⊙ halo at z = 3, including stellar, dust, and Lyα radiative transfer, we can model the ALMA+STIS observations and demonstrate that Lyα photons escaping from the central submillimeter sources are expected to resonantly scatter in neutral hydrogen, the majority of which is predicted to be associated with halo substructure. We show how this process gives rise to extended Lyα emission with similar surface brightness and morphology to observed giant LABs.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Geach, J. E.0000-0003-4964-4635
Steidel, C. C.0000-0002-4834-7260
Additional Information:© 2016 The American Astronomical Society. Received 2016 June 10; revised 2016 July 21; accepted 2016 August 8; published 2016 November 14. We thank the referee for a constructive report that has improved this work. J.E.G. is supported by a Royal Society University Research Fellowship. Partial support for D.N. was provided by NSF AST-1442650, NASA HST AR-13906.001, and a Cottrell College Science Award. M.H. acknowledges the support of the Swedish Research Council, Vetenskapsrådet and the Swedish National Space Board (SNSB), and is a Fellow of the Knut and Alice Wallenberg Foundation. H.D. acknowledges financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) under the 2014 Ramón y Cajal program MINECO RYC-2014-15686. A.V. is supported by a Research Fellowship from the Leverhulme Trust. The authors acknowledge excellent support of the UK ALMA Regional Centre Node. This letter makes use of the following ALMA data: ADS/JAO.ALMA#2013.1.00704S, ADS/JAO.ALMA#2013.1.00922.S. ALMA is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan), together with NRC (Canada) and NSC and ASIAA (Taiwan), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. This work was supported by the ALMA Japan Research Grant of NAOJ Chile Observatory, NAOJ-ALMA-0086.
Funding AgencyGrant Number
NASAHST AR-13906.001
Cottrell College Science AwardUNSPECIFIED
Swedish Research CouncilUNSPECIFIED
Swedish National Space Board (SNSB)UNSPECIFIED
Knut and Alice Wallenberg FoundationUNSPECIFIED
Ministerio de Economía y Competitividad (MINECO)RYC-2014-15686
Leverhulme TrustUNSPECIFIED
National Astronomical Observatory of JapanNAOJ-ALMA-0086
Subject Keywords:galaxies: evolution – galaxies: halos – galaxies: high-redshift
Issue or Number:1
Record Number:CaltechAUTHORS:20161116-125343348
Persistent URL:
Official Citation:J. E. Geach et al 2016 ApJ 832 37
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:72058
Deposited By: Tony Diaz
Deposited On:17 Nov 2016 00:21
Last Modified:11 Nov 2021 04:55

Repository Staff Only: item control page