Astronomy and Astrophysics – Astrophysics
Scientific paper
Jul 2010
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010a%26a...517a..79l&link_type=abstract
Astronomy and Astrophysics, Volume 517, id.A79
Astronomy and Astrophysics
Astrophysics
3
Ism: Clouds, Dust, Extinction, Infrared: Ism
Scientific paper
Aims: We study an undocumented large translucent cloud, detected by means of its enhanced radiation in the SHASSA (Southern H-Alpha Sky Survey Atlas) survey. We consider whether its excess surface brightness can be explained by light scattered off the dust grains in the cloud, or whether emission from in situ ionized gas is required. In addition, we aim to determine the temperature of dust, the mass of the cloud, and its possible star formation activity. Methods: We compare the observed Hα surface brightness of the cloud with predictions of a radiative transfer model. We use the WHAM (Wisconsin H-Alpha Mapper) survey as a source for the Galactic Hα interstellar radiation field illuminating the cloud. Visual extinction through the cloud is derived using 2MASS J, H, and K band photometry. We use far-IR ISOSS (ISO Serendipitous Survey), IRAS, and DIRBE data to study the thermal emission of dust. The LAB (The Leiden/Argentine/Bonn Galactic HI Survey) is used to study 21 cm HI emission associated with the cloud. Results: Radiative transfer calculations of the Galactic diffuse Hα radiation indicate that the surface brightness of the cloud can be explained solely by radiation scattered off dust particles in the cloud. The maximum visual extinction through the cloud is about 1.2 mag. The cloud is found to be associated with 21 cm HI emission at a velocity ~-9 km s-1. The total mass of the cloud is about 550-1000 M&sun;. There is no sign of star formation in this cloud. The distance of the cloud is estimated from the Hipparcos data to be ~100 pc.
Present address: Department of Physics, Division of Geophysics and Astronomy, PO Box 64, 00014 University of Helsinki, Finland.
Juvela Mika
Lehtinen Kimmo K.
Mattila Kalevi
No associations
LandOfFree
Scattered Hα emission from a large translucent cloud G294-24 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Scattered Hα emission from a large translucent cloud G294-24, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Scattered Hα emission from a large translucent cloud G294-24 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1642057