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Sardinia Radio Telescope (SRT) observations of Local Group dwarf galaxies

Published online by Cambridge University Press:  16 July 2018

A. Tarchi ,
P. Castangia ,
G. Surcis ,
A. Brunthaler ,
K. M. Menten ,
M. S. Pawlowski ,
A. Melis ,
S. Casu ,
M. Murgia  and
A. Trois
...Show all authors
A. Tarchi
Affiliation:
INAF-Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius email: atarchi@oa-cagliari.inaf.it
P. Castangia
Affiliation:
INAF-Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius email: atarchi@oa-cagliari.inaf.it
G. Surcis
Affiliation:
INAF-Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius email: atarchi@oa-cagliari.inaf.it
A. Brunthaler
Affiliation:
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 71,53121 Bonn, Germany
K. M. Menten
Affiliation:
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 71,53121 Bonn, Germany
M. S. Pawlowski
Affiliation:
Department of Physics and Astronomy, University of California, Irvine, CA 92697, USA
A. Melis
Affiliation:
INAF-Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius email: atarchi@oa-cagliari.inaf.it
S. Casu
Affiliation:
INAF-Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius email: atarchi@oa-cagliari.inaf.it
M. Murgia
Affiliation:
INAF-Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius email: atarchi@oa-cagliari.inaf.it
A. Trois
Affiliation:
INAF-Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius email: atarchi@oa-cagliari.inaf.it
R. Concu
Affiliation:
INAF-Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius email: atarchi@oa-cagliari.inaf.it
C. Henkel
Affiliation:
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 71,53121 Bonn, Germany Astronomy Departement, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia
J. Darling
Affiliation:
Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309-0389, USA
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Abstract

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The dwarf galaxies in the Local Group (LG) reveal a surprising amount of spatial structuring. In particular, almost all non-satellite dwarfs belong to one of two planes that show a very pronounced symmetry. In order to determine if these structures in the LG are dynamically stable or, alternatively, if they only represent transient alignments, proper motion measurements of these galaxies are required. A viable method to derive proper motions is offered by VLBI studies of 22-GHz water (and 6.7-GHz methanol) maser lines in star-forming regions.

In 2016, in the framework of the Early Science Program of the Sardinia Radio Telescope (SRT), we have conducted an extensive observational campaign to map the entire optical body of all the LG dwarf galaxies that belong to the two planes, at C and K band, in a search for methanol and water maser emission.

Here, we outline the project and present its first results on 3 targets, NGC 6822, IC 1613, and WLM. While no luminous maser emission has been detected in these galaxies, a number of interesting weaker detections has been obtained, associated with particularly active star forming regions. In addition, we have produced deep radio continuum maps for these galaxies, aimed at investigating their star forming activity and providing an improved assessment of star formation rates in these galaxies.

Keywords

galaxies: dwarfLocal Grouptelescopestechniques: spectroscopicradio lines: galaxiesmasersradio continuum: galaxies
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 13 , Symposium S336: Astrophysical Masers: Unlocking the Mysteries of the Universe , September 2017 , pp. 109 - 112
Copyright
Copyright © International Astronomical Union 2018 

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