English   español  
Por favor, use este identificador para citar o enlazar a este item: http://hdl.handle.net/10261/5051
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:

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

AutorAtek, Hakim; Kunth, Daniel; Hayes, Matthew; Östlin, G.; Mas-Hesse, J. Miguel
Palabras claveGalaxies: 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)
Fecha de publicación22-may-2008
EditorEDP Sciences
CitaciónarXiv:0805.3501v1 [astro-ph]
Astronomy and Astrophysics 2008 [to be announced]
Resumen[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.
DescripciónAccepted for publication in A&A.-- 19 pages, 15 figures.
Aparece en las colecciones: (CAB) Artículos
Ficheros en este ítem:
Fichero Descripción Tamaño Formato  
0805.3501v1.pdf2,63 MBAdobe PDFVista previa
Mostrar el registro completo

NOTA: Los ítems de Digital.CSIC están protegidos por copyright, con todos los derechos reservados, a menos que se indique lo contrario.