Main Page
About Science
Faculty Deanship
Letter of Dean
Overview of Deanship
Vice Deans
Vice Dean
Letter of Vice-dean
Overview of Vice-deanship
Vice Dean for Graduate Studies
Letter of Vice Dean for Graduate Studies
Overview of Vice Dean of Postgraduate Studies
Research and Innovation Unit
Vice Dean for Girls Campus
Faculty Management
Letter of Managing Director-Boys Campus
Letter of Managing Director-Girls Campus
Overview of Management
Educational Affairs
Males Campus
Staff
Females Campus
Contact Us
Research
عربي
English
About
Admission
Academic
Research and Innovations
University Life
E-Services
Search
Faculty of Sciences
Document Details
Document Type
:
Article In Journal
Document Title
:
On the missing 2175 Å-bump in the Calzetti extinction curve
On the missing 2175 Å-bump in the Calzetti extinction curve
Subject
:
Astronomyِ
Document Language
:
English
Abstract
:
Aims. The aim of the paper is to give a physical explanation of the absence of the feature in the Calzetti extinction curve. Methods.We analyze the dust attenuation of a homogeneous source seen through a distant inhomogeneous distant screen. The inhomogeneities are described through an idealized isothermal turbulent medium where the probability distribution function (PDF) of the column density is log-normal. In addition it is assumed that below a certain critical column density the carriers of the extinction bump at 2175 Å are being destroyed by the ambient UV radiation field. Results. Turbulence is found to be a natural explanation not only of the flatter curvature of the Calzetti extinction curve but also of the missing bump provided the critical column density is NH = 1021 cm-2. The density contrast needed to explain both characteristics is well consistent with the Mach number of the cold neutral medium of our own Galaxy which suggests a density contrast s.σp≈6.
ISSN
:
0004-6361
Journal Name
:
Astronomy and Astrophysics
Volume
:
533
Issue Number
:
1
Publishing Year
:
1432 AH
2011 AD
Article Type
:
Article
Added Date
:
Wednesday, April 25, 2012
Researchers
Researcher Name (Arabic)
Researcher Name (English)
Researcher Type
Dr Grade
Email
Jörg F Fischera
Fischera, Jörg F
Researcher
Doctorate
fischera@mso.anu.edu.au
Michael A Dopita
Dopita, Michael A
Researcher
Doctorate
michael.dopita@anu.edu.au
Files
File Name
Type
Description
33028.pdf
pdf
Abstract
Back To Researches Page