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Hot gas, cold gas and sub-haloes in a Lyman α blob at redshift 2.38

Francis, Paul J. and Dopita, Michael A. and Colbert, James W. and Palunas, Povilas and Scarlata, Claudia and Teplitz, Harry and Williger, Gerard M. and Woodgate, Bruce E. (2013) Hot gas, cold gas and sub-haloes in a Lyman α blob at redshift 2.38. Monthly Notices of the Royal Astronomical Society, 428 (1). pp. 28-39. ISSN 0035-8711. doi:10.1093/mnras/sts010.

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We present integral field spectroscopy of a Lyman α blob at redshift 2.38, with a spectral resolution three times better than previous published work. As with previous observations, the blob has a chaotic velocity structure, much of which breaks up into multiple components. Our spectroscopy shows, however, that some of these multiple components are extremely narrow: they have velocity widths of less than 100 km s^(−1). Combining these new data with previous observations, we argue that this Lyman α blob resides in a dark matter halo of around 10^(13) M_⊙. At the centre of this halo are two compact red massive galaxies. They are surrounded by hot gas, probably a superwind from merger-induced nuclear starbursts. This hot gas has shut down star formation in the non-nuclear region of these galaxies, leading to their red-and-dead colours. A filament or lump of infalling cold gas is colliding with the hot gas phase and being shocked to high temperatures, while still around 30 kpc from the red galaxies. The shock region is self-absorbed in Lyman α but produces C iv emission. Further out still, the cold gas in a number of sub-haloes is being lit up, most likely by a combination of tidally triggered star formation, bow shocks as they plough through the hot halo medium, resonant scattering of Lyman α from the filament collision and tidal stripping of gas which enhances the Lyman α escape fraction. The observed Lyman α emission from the blob is dominated by the sum of the emission from these sub-haloes. On statistical grounds, we argue that Lyman α blobs are not greatly elongated in shape and that most are not powered by ionization or scattering from a central active galactic nucleus or starburst.

Item Type:Article
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URLURL TypeDescription
Scarlata, Claudia0000-0002-9136-8876
Teplitz, Harry0000-0002-7064-5424
Additional Information:© 2012 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2012 September 14. Received 2012 September 12; in original form 2012 August 14. First published online: October 23, 2012. We would like to thank Ralph Sutherland for several useful conversations. The Millennium Simulation data bases used in this paper and the web application providing online access to them were constructed as part of the activities of the German Astrophysical Virtual Observatory. This work is based in part on observations obtained as part of programme GS-2005B-Q-23 at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciîncia, Tecnologia e Inovaҫão (Brazil) band Ministerio de Ciencia, Tecnologa e Innovación Productiva (Argentina). This work is also based in part on observations made with the NASA/ESA Hubble Space Telescope and those obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESA) and the Canadian Astronomy Data Centre (CADC/NRC/CSA). MAD acknowledges ARC support under Discovery project DP0984657.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Australian Research CouncilDP0984657
Subject Keywords:galaxies: haloes; galaxies: high-redshift
Issue or Number:1
Record Number:CaltechAUTHORS:20130604-110531015
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:38780
Deposited On:04 Jun 2013 21:26
Last Modified:09 Nov 2021 23:39

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