PROBING EXTRAGALACTIC DUST THROUGH NEARBY GAMMA-RAY BURST AFTERGLOWS

Journal Article · Wed Feb 10 00:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/710/1/648· OSTI ID:21394496

Liang, S L ^[1]

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1. Department of Physics, Hunan Normal University, Changsha 410071 (China)

The quantities and wavelength dependencies of the dust extinction along the lines of sight toward 33 nearby gamma-ray bursts (GRBs) with redshifts z < 2 are derived from fitting their afterglow spectral energy distributions. Unlike previous studies which often assume a specific extinction law like that of the Milky Way (MW) and the Large and Small Magellanic Clouds (LMC/SMC), our approach-we call it the 'Drude' approach-is more flexible in determining the true wavelength dependence of the extinction (while the shape of the extinction curve inferred from that relying on a priori assumption of a template extinction law is, of course, fixed). The extinction curves deduced from the Drude approach display a wide diversity of shapes, ranging from relatively flat curves to curves which are featureless and steeply rise toward the far-ultraviolet, and from curves just like that of the MW, LMC, and SMC to curves resembling that of the MW and LMC but lacking the 2175 A bump. The visual extinction A{sub V} derived from the Drude approach is generally larger by a factor of {approx}2-5 than that inferred by assuming a SMC-type template extinction law. Consistent with previous studies, the extinction-to-gas ratio is mostly smaller than that of the MW, and does not seem to correlate with the shape of the extinction curve. It is shown that the standard silicate-graphite interstellar grain model closely reproduces the extinction curves of all 33 GRBs host galaxies. For these 33 bursts at z < 2, we find no evidence for the evolution of the dust extinction, dust sizes, and relative abundances of silicate to graphite on redshifts.

• OSTI ID: 21394496
• Journal Information: Astrophysical Journal, Vol. 710, Issue 1; Other Information: DOI: 10.1088/0004-637X/710/1/648; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABUNDANCE
AFTERGLOW
COSMIC GAMMA BURSTS
DUSTS
ENERGY SPECTRA
FAR ULTRAVIOLET RADIATION
FREQUENCY DEPENDENCE
GAMMA RADIATION
GRAPHITE
INTERSTELLAR GRAINS
MAGELLANIC CLOUDS
MILKY WAY
RED SHIFT
SILICATES
CARBON
COSMIC RADIATION
ELECTROMAGNETIC RADIATION
ELEMENTS
GALAXIES
IONIZING RADIATIONS
MINERALS
NONMETALS
OXYGEN COMPOUNDS
PARTICLES
PRIMARY COSMIC RADIATION
RADIATIONS
SILICON COMPOUNDS
SPECTRA
ULTRAVIOLET RADIATION