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Physical Sciences and Mathematics Commons™
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Full-Text Articles in Physical Sciences and Mathematics
The Opacity Of Spiral Galaxy Disks. Viii. Structure Of The Cold Ism., Benne W. Holwerda, B. Draine, K. D. Gordon, R. A. Gonzalez, D. Calzetti, M. Thornley, B. Buckalew, Ronald J. Allen, P C. Van Der Kruit
The Opacity Of Spiral Galaxy Disks. Viii. Structure Of The Cold Ism., Benne W. Holwerda, B. Draine, K. D. Gordon, R. A. Gonzalez, D. Calzetti, M. Thornley, B. Buckalew, Ronald J. Allen, P C. Van Der Kruit
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The quantity of dust in a spiral disk can be estimated using the dust’s typical emission or the extinction of a known source. In this paper we compare two techniques, one based on emission and one on absorption, applied to sections of 14 disk galaxies. The two measurements reflect, respectively, the average and apparent optical depth of a disk section. Hence, they depend differently on the average number and optical depth of ISM structures in the disk. The small-scale geometry of the cold ISM is critical for accurate models of the overall energy budget of spiral disks. ISM geometry, relative …
Spiral Disk Opacity From Occulting Galaxy Pairs In The Sloan Digital Sky Survey., Benne W. Holwerda, W. C. Keel, A. Bolton
Spiral Disk Opacity From Occulting Galaxy Pairs In The Sloan Digital Sky Survey., Benne W. Holwerda, W. C. Keel, A. Bolton
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A spiral galaxy partially overlapping a more distant elliptical offers a unique opportunity to measure the dust extinction in the foreground spiral. From the Sloan Digital Sky Survey (SDSS) DR4 spectroscopic sample, we selected 83 occulting galaxy pairs and measured disk opacity over the redshift range z ¼ 0:0Y0:2 with the goal of determining the recent evolution of disk dust opacity. The enrichment of the ISM changes over the lifetime of a disk, and it is reasonable to expect the dust extinction properties of spiral disks as a whole to change over their lifetime. When they do, the change will …
Gaps In The Cloud Cover? : Comparing Extinction Measures In Spiral Disks., Benne W. Holwerda, M. Meyer, M. W. Regan, D. Calzetti, K. D. Gordon, J. D. Smith, D. Dale, C. W. Engelbracht, T. Jarrett, M. Thornley, C. Bot, B. Buckalew, R. C. Kennicutt, R. A. Gonzalez
Gaps In The Cloud Cover? : Comparing Extinction Measures In Spiral Disks., Benne W. Holwerda, M. Meyer, M. W. Regan, D. Calzetti, K. D. Gordon, J. D. Smith, D. Dale, C. W. Engelbracht, T. Jarrett, M. Thornley, C. Bot, B. Buckalew, R. C. Kennicutt, R. A. Gonzalez
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Dust in galaxies can be mapped either by the FIR/submillimeter emission, the optical or infrared reddening of starlight, or the extinction of a known background source. We compare two dust extinction measurements for a set of 15 sections in 13 nearby galaxies to determine the scale of the dusty interstellar medium ( ISM ) responsible for disk opacity: one using stellar reddening and the other a known background source. In our earlier papers, we presented extinction measurements of 29 galaxies, based on calibrated counts of distant background objects identified though foreground disks in Hubble Space Telescope WFPC2 images. For the …