Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· arXiv e-print (arXiv:0810.4142)
· References in the article
· Citations to the Article (2) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (20)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
Low-Velocity Halo Clouds
Authors:
Peek, J. E. G.; Heiles, Carl; Putman, M. E.; Douglas, Kevin
Affiliation:
AA(Department of Astronomy, University of California, Berkeley, CA 94720, USA ), AB(Department of Astronomy, University of California, Berkeley, CA 94720, USA ), AC(Department of Astronomy, Columbia University, New York, NY 10027, USA ), AD(Space Sciences Laboratory, University of California, Berkeley, CA 94720, USA ; Present address: Astrophysics Group, School of Physics, University of Exeter, UK.)
Publication:
The Astrophysical Journal, Volume 692, Issue 1, pp. 827-838 (2009). (ApJ Homepage)
Publication Date:
02/2009
Origin:
IOP
ApJ Keywords:
galaxies: formation, Galaxy: halo, ISM: clouds, ISM: kinematics and dynamics
DOI:
10.1088/0004-637X/692/1/827
Bibliographic Code:
2009ApJ...692..827P

Abstract

Models that reproduce the observed high-velocity clouds (HVCs) also predict clouds at lower radial velocities that may easily be confused with Galactic disk (|z|< 1 kpc) gas. We describe the first search for these low-velocity halo clouds (LVHCs) using Infrared Astronomical Satellite (IRAS) data and the initial data from the Galactic Arecibo L-band Feed Array survey in H I. The technique is based upon the expectation that such clouds should, like HVCs, have very limited infrared (IR) thermal dust emission as compared to their H I column density. We describe our "displacement-map" technique for robustly determining the dust-to-gas ratio (DGR) of clouds and the associated errors that take into account the significant scatter in the IR flux from the Galactic disk gas. We find that there exist lower-velocity clouds that have extremely low DGRs, consistent with being in the Galactic halo—candidate LVHCs. We also confirm the lack of dust in many HVCs with the notable exception of complex M, which we consider to be the first detection of dust in HVCs. We do not confirm the previously reported detection of dust in complex C. In addition, we find that most intermediate- and low-velocity clouds that are part of the Galactic disk have a higher 60 μm/100 μm flux ratio than is typically seen in Galactic H I, which is consistent with a previously proposed picture in which fast-moving Galactic clouds have smaller, hotter dust grains.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints