Serendipity observations of far infrared cirrus emission in the Spitzer Infrared Nearby Galaxies Survey: analysis of far-infrared correlations
Abstract
We present an analysis of far-infrared (FIR) dust emission from diffuse cirrus clouds. This study is based on serendipitous observations at 160 μm at high-galactic latitude with the Multiband Imaging Photometer onboard the Spitzer Space Telescope by the Spitzer Infrared Nearby Galaxies Survey. These observations are complemented with IRIS data at 100 and 60 μm and constitute one of the most sensitive and unbiased samples of FIR observations at a small scale of diffuse interstellar clouds. Outside regions dominated by the cosmic infrared background fluctuations, we observe a substantial scatter in the 160/100 colors from cirrus emission. We compared the 160/100 color variations to 60/100 colors in the same fields and find a trend of decreasing 60/100 with increasing 160/100. This trend cannot be accounted for by current dust models by changing solely the interstellar radiation field. It requires a significant change of dust properties such as grain size distribution or emissivity or a mixing of clouds in different physical conditions along the line of sight. These variations are important as a potential confusing foreground for extragalactic studies.
Additional Information
©2009 The American Astronomical Society. Received 2008 October 13; accepted 2009 January 13; published 2009 March 31. We would like to thank our referee M. Rowan-Robinson for his useful and interesting comments and A. Efstathiou for his helpwith their cirrusmodel. We are also grateful to L. Cambrésy for useful discussions and work on upper limit for extinction in our fields. Facilities: Spitzer.Attached Files
Published - Bot2009p1478Astrophys_J.pdf
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Additional details
- Eprint ID
- 14049
- Resolver ID
- CaltechAUTHORS:20090422-150618966
- Created
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2009-04-29Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)