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The Effect of Dust Geometry on the Lyα Output of Galaxies

Scarlata, C. and Colbert, J. and Teplitz, H. I. and Panagia, N. and Hayes, M. and Siana, B. and Rau, A. and Francis, P. and Caon, A. and Pizzella, A. and Bridge, C. (2009) The Effect of Dust Geometry on the Lyα Output of Galaxies. Astrophysical Journal Letters, 704 (2). L98-L102. ISSN 2041-8205.

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We present the optical spectroscopic follow-up of 31 z = 0.3 Lyα emitters, previously identified by Deharveng et al. We find that 17% of the Lyα emitters have line ratios that require the hard ionizing continuum produced by an active galactic nucleus. The uniform dust screen geometry traditionally used in studies similar to ours is not able to simultaneously reproduce the observed high Lyα/Hα and Hα/Hβ line ratios. We consider different possibilities for the geometry of the dust around the emitting sources. We find that also a uniform mixture of sources and dust does not reproduce the observed line ratios. Instead, these are well reproduced by a clumpy dust screen. This more realistic treatment of the geometry results in extinction corrected (Lyα/Hα) C values consistent with case B recombination theory, whereas a uniform dust screen model would imply values (Lyα/Hα) C higher than 8.7. Our analysis shows that there is no need to invoke ad hoc multiphase media in which the Lyα photons only scatter between the dusty clouds and eventually escape

Item Type:Article
Related URLs:
URLURL TypeDescription
Scarlata, C.0000-0002-9136-8876
Teplitz, H. I.0000-0002-7064-5424
Siana, B.0000-0002-4935-9511
Rau, A.0000-0001-5990-6243
Additional Information:© 2009 American Astronomical Society. Received 2009 July 16; accepted 2009 September 8; published 2009 October 5.
Group:Infrared Processing and Analysis Center (IPAC)
Subject Keywords:galaxies: ISM; ISM: structure
Issue or Number:2
Record Number:CaltechAUTHORS:20091104-113041493
Persistent URL:
Official Citation:The Effect of Dust Geometry on the Lyα Output of Galaxies C. Scarlata, J. Colbert, H. I. Teplitz, N. Panagia, M. Hayes, B. Siana, A. Rau, P. Francis, A. Caon, A. Pizzella, and C. Bridge 2009 ApJ 704 L98-L102 doi: 10.1088/0004-637X/704/2/L98
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16578
Deposited By: Jason Perez
Deposited On:04 Nov 2009 23:08
Last Modified:03 Oct 2019 01:14

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