skip to main content

SciTech ConnectSciTech Connect

Title: Extragalactic interstellar extinction curves: Indicators of local physical conditions

Normalized interstellar extinction curves (ISECs) in the Milky Way and other galaxies show a variety of shapes. This variety is attributed to differences along different sight lines in the abundances of the several dust and gas components contributing to extinction. In this paper we propose that these abundance differences are not arbitrary but are a specific consequence of the physical conditions on those sight lines. If this proposal is correct, then it implies that ISECs contain information about physical conditions in the regions generating extinction. This may be particularly important for high redshift galaxies where information on the conditions may be difficult to obtain. We adopt a model of extinction carriers in which the solid and gaseous components are not immutable but respond time-dependently to the local physics. We validate this model by fitting extinction curves measured on sight lines in the Magellanic Clouds and obtained for the gamma-ray burst afterglow GRB 080605. We present results for this model as follows: (1) we show that computed ISECs are controlled by a small number of physical parameters, (2) we demonstrate the sensitivity of computed ISECs to these parameters, (3) we compute as examples ISECs for particular galaxy types, and (4) wemore » note that different galaxy types have different shapes of ISEC.« less
Authors:
 [1] ; ;  [2]
  1. INAF-Osservatorio Astronomico di Palermo, P.zza Parlamento 1, I-90134 Palermo (Italy)
  2. Department of Physics and Astronomy, University College London Gower Street, London WC1E 6BT (United Kingdom)
Publication Date:
OSTI Identifier:
22356619
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 788; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; AFTERGLOW; COSMIC GAMMA BURSTS; DUSTS; EVOLUTION; MAGELLANIC CLOUDS; MILKY WAY; RED SHIFT; SENSITIVITY; TIME DEPENDENCE