Voyager Measurements of Hydrogen Lyman-#945; Diffuse Emission from the Milky Way
Rosine Lallement1,2,*, Eric Quémerais2, Jean-Loup Bertaux2, Bill R. Sandel3, Vlad Izmodenov4
+ Author Affiliations

1GEPI, Observatoire de Paris, CNRS, Université Paris Diderot, Place Jules Janssen, 92190, Meudon, France.
2LATMOS-IPSL, Université Versailles-St Quentin, Guyancourt, France.
3Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85719, USA.
4Lomonosov Moscow State University, Moscow, Russia.
#8629;*To whom correspondence should be addressed. E-mail: rosine.lallement@obspm.fr

ABSTRACT

Doppler-shifted hydrogen Lyman-alpha (Ly#945;) emission from galaxies is currently measured and used in cosmology as an indicator of star formation. Until now, the Milky Way emission has not been detected, owing to far brighter local sources, including the H Glow—i.e., solar Ly#945; radiation backscattered by interstellar atoms that flow within the solar system. Because observations from the Voyager spacecraft, now leaving the heliosphere, are decreasingly affected by the H glow, the Ultraviolet Spectrographs are detecting Ly#945; diffuse emission from our galaxy. The surface brightness toward nearby star-forming regions is about 3 to 4 Rayleigh. The escape fraction of the radiation from the brightest H II regions is on the order of 3% and is highly spatially variable. These results will help constraining models of Ly#945; radiation transfer in distant galaxies.

http://www.sciencemag.org/content/early ... 2b09a7de05

Da sonde Voyager Via Lattea mai vista
Le due missioni della Nasa 'sbirciano' le culle delle stelle
02 dicembre, 19:32

(ANSA) - ROMA, 2 DIC - Dalla loro posizione privilegiata ai confini del Sistema Solare le sonde Voyager sono riuscite ad osservare la Via Lattea senza disturbi. Hanno visto così un fenomeno, quello delle emissioni Lyman-alpha, probabile indizio della presenza di zone di formazione delle stelle. Le nuove osservazioni hanno potuto confermare l'ipotesi che queste linee di assorbimento dell'idrogeno hanno origine proprio dalle regioni circostanti le nuove stelle e permettere così una migliore comprensione delle galassie.

http://www.ansa.it/web/notizie/rubriche ... 80423.html