English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/5051
Share/Impact:
Statistics
logo share SHARE   Add this article to your Mendeley library MendeleyBASE
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:

Title

On the Detectability of Lyman-alpha Emission in Star-forming Galaxies: The Role of Dust

AuthorsAtek, Hakim; Kunth, Daniel; Hayes, Matthew; Östlin, G.; Mas-Hesse, J. Miguel
KeywordsGalaxies: starburst
Galaxies: ISM
Ultraviolet: galaxies
ISM: dust, extinction
Galaxies: individual: (Haro 11, ESO 338-04, NGC 6090, IRAS 08339+6517, SBS 0335-052, Tololo 65)
Issue Date22-May-2008
PublisherEDP Sciences
CitationarXiv:0805.3501v1 [astro-ph]
Astronomy and Astrophysics 2008 [to be announced]
Abstract[Context] Lyman-alpha (Lyα) is now widely used to investigate the galaxy formation and evolution in the high redshift universe. However, without a rigorous understanding of the processes which regulate the Lyα escape fraction, physical interpretations of high-z observations remain questionable.
[Aims] To examine six nearby star-forming galaxies to disentangle the role of the dust from other parameters such as gas kinematics, geometry and ISM morphology in the obscuration of Lyα. Thereby we aim to understand the Lyα escape physics and infer the implications for high-redshift studies.
[Methods] We use HST/ACS to produce continuum-subtracted Lyα maps, and ground-based observations (ESO/NTT and NOT) to map the Hα emission and the extinction E(B-V) in the gas phase derived from the Balmer decrement Hα/Hβ.
[Results] When large outflows are present, the Lyα emission appears not to correlate with the dust content, confirming the role of the Hi kinematics in the escape of Lyα photons. In the case of a dense, static Hi covering, we observe a damped absorption with a declining relationship between Lyα and E(B-V).
[Conclusions] The dust is not necessarily the main Lyα escape regulatory factor. ISM kinematics and geometry may play a more significant role. The failure of simple dust correction to recover the intrinsic Lyα/Hα ratio or the total star formation rate should prompt us to be more cautious when interpreting high-z observations and related properties, such as SFRs based on Lyα alone. To this end we propose a more realistic calibration for SFR(Lyα) which accounts for dust attenuation and resonant scattering effects via the Lyα escape fraction.
DescriptionAccepted for publication in A&A.-- 19 pages, 15 figures.
URIhttp://hdl.handle.net/10261/5051
ISSN0004-6361
Appears in Collections:(CAB) Artículos
Files in This Item:
File Description SizeFormat 
0805.3501v1.pdf2,63 MBAdobe PDFThumbnail
View/Open
Show full item record
Review this work
 


WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.