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Record 1 of 29753
The Reddening law outside the local group galaxies: The case of NGC 7552 and NGC 5236
External Online Source: doi:10.1086/174309
Author and Affiliation:
Kinney, Anne L.(Space Telescope Science Institute, Baltimore, MD, United States)
Calzetti, Daniela(Space Telescope Science Institute, Baltimore, MD, United States)
Bica, Eduardo(Insituto de Fisica, Porto Alegre, Brazil)
Storchi-Bergmann, Thaisa(Insituto de Fisica, Porto Alegre, Brazil)
Abstract: The dust reddening law from the UV to the near-IR for the extended regions of galaxies is here derived from the spectral distributions of the starburst spiral galaxies NGC 7552 and NGC 5236. The centers of these galaxies have similar absorption and emission line spectra, differing only if the strength of their interstellar lines and in the continuum distribution, with NGC 7552 appearing more reddened than NGC 5236. The disk of NGC 7552 is more inclined, and there is evidence that its center is observed through additional foreground dust and gas clouds, as compared to the center of NGC 5236. While the galaxies can be expected to have similar dust content, they are known to have different dust path lengths to our line of sight. Therefore, differences in the shape of the spectra can be attributed mainly to the effects of dust, allowing us to probe for the first time the properties of the reddening law outside the local group of galaxies. We derive the reddening law based on the optical depth of the emission line of H Alpha and H Beta and also based on the continuum distribtuion. We find that the optical depth from the emission line regions are about twice the optical depth of the continuum regions. Thus, dereddening a starburst galaxy by scaling the Milky Way reddening laws to optical depths obtained from the H Alpha/H Beta line ratio overcompensates for the effect of dust.
Publication Date: Jul 01, 1994
Document ID:
19950037353
(Acquired Dec 28, 1995)
Accession Number: 95A68952
Subject Category: ASTROPHYSICS
Document Type: Journal Article
Publication Information: The Astrophysical Journal, Part 1 (ISSN 0004-637X); 429; 1; p. 172-176
Publisher Information: United States
Contract/Grant/Task Num: NAG5-1143
Financial Sponsor: NASA; United States
Organization Source: NASA Goddard Space Flight Center; Greenbelt, MD, United States
Description: 5p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: ASTRONOMICAL MODELS; COSMIC DUST; INTERSTELLAR EXTINCTION; SPECTRAL ENERGY DISTRIBUTION; STARBURST GALAXIES; H ALPHA LINE; H BETA LINE; OPTICAL THICKNESS
Imprint And Other Notes: The Astrophysical Journal, Part 1 vol. 429, no. 1 p. 172-176 July 1, 1994
Miscellaneous Notes: Research sponsored by STSCI Directors Research Fund, CNP, CAPES, FAPERGS, IF-UFRGS and UPD
Availability Source: Other Sources
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