Universität zu Köln

Groves, Brent, Krause, Oliver, Sandstrom, Karin, Schmiedeke, Anika, Leroy, Adam ORCID: 0000-0002-2545-1700, Linz, Hendrik, Kapala, Maria, Rix, Hans-Walter, Schinnerer, Eva ORCID: 0000-0002-3933-7677, Tabatabaei, Fatemeh, Walter, Fabian ORCID: 0000-0003-4793-7880 and da Cunha, Elisabete ORCID: 0000-0001-9759-4797 (2012). The heating of dust by old stellar populations in the bulge of M31. Mon. Not. Roy. Astron. Soc., 426 (2). S. 892 - 903. HOBOKEN: WILEY-BLACKWELL. ISSN 0035-8711

Full text not available from this repository.

Abstract

We use new Herschel multiband imaging of the Andromeda galaxy to analyse how dust heating occurs in the central regions of galaxy spheroids that are essentially devoid of young stars. We construct a dust temperature map of M31 through fitting modified blackbodies to the Herschel data, and find that the temperature within 2?kpc rises strongly from the mean value in the disc of 17 +/- 1 to similar to 35?K at the centre. Ultraviolet (UV) to near-infrared (IR) imaging of the central few kpc shows directly the absence of young stellar populations, delineates the radial profile of the stellar density and demonstrates that even the near-UV dust extinction is optically thin in M31's bulge. This allows the direct calculation of the stellar radiation heating in the bulge, U*(r), as a function of radius. The increasing temperature profile in the centre matches that expected from the stellar heating, i.e. that the dust heating and cooling rates track each other over nearly two orders of magnitude in U*. The modelled dust heating is in excess of the observed dust temperatures, suggesting that it is more than sufficient to explain the observed IR emission. Together with the wavelength-dependent absorption cross-section of the dust, this demonstrates directly that it is the optical, not UV, radiation that sets the heating rate. This analysis shows that neither young stellar populations nor stellar near-UV radiation is necessary to heat dust to warm temperatures in galaxy spheroids. Rather, it is the high densities of Gyr-old stellar populations that provide a sufficiently strong diffuse radiation field to heat the dust. To the extent which these results pertain to the tenuous dust found in the centres of early-type galaxies remains yet to be explored.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Groves, Brent UNSPECIFIED UNSPECIFIED UNSPECIFIED Krause, Oliver UNSPECIFIED UNSPECIFIED UNSPECIFIED Sandstrom, Karin UNSPECIFIED UNSPECIFIED UNSPECIFIED Schmiedeke, Anika UNSPECIFIED UNSPECIFIED UNSPECIFIED Leroy, Adam UNSPECIFIED orcid.org/0000-0002-2545-1700 UNSPECIFIED Linz, Hendrik UNSPECIFIED UNSPECIFIED UNSPECIFIED Kapala, Maria UNSPECIFIED UNSPECIFIED UNSPECIFIED Rix, Hans-Walter UNSPECIFIED UNSPECIFIED UNSPECIFIED Schinnerer, Eva UNSPECIFIED orcid.org/0000-0002-3933-7677 UNSPECIFIED Tabatabaei, Fatemeh UNSPECIFIED UNSPECIFIED UNSPECIFIED Walter, Fabian UNSPECIFIED orcid.org/0000-0003-4793-7880 UNSPECIFIED da Cunha, Elisabete UNSPECIFIED orcid.org/0000-0001-9759-4797 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-481567
DOI:	10.1111/j.1365-2966.2012.21696.x
Journal or Publication Title:	Mon. Not. Roy. Astron. Soc.
Volume:	426
Number:	2
Page Range:	S. 892 - 903
Date:	2012
Publisher:	WILEY-BLACKWELL
Place of Publication:	HOBOKEN
ISSN:	0035-8711
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language EARLY-TYPE GALAXIES; HERSCHEL REFERENCE SURVEY; STAR-FORMATION HISTORIES; HUBBLE-SPACE-TELESCOPE; ANDROMEDA GALAXY; MOLECULAR GAS; INFRARED-EMISSION; INTERSTELLAR DUST; NEARBY GALAXIES; IONIZED-GAS Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/48156