UZH-Logo

H I clouds in the proximity of M 33


Grossi, M; Giovanardi, C; Corbelli, E; Giovanelli, R; Haynes, M P; Martin, H R; Saintonge, A; Dowell, J D (2008). H I clouds in the proximity of M 33. Astronomy and Astrophysics, 487(1):161-175.

Abstract

Aims. Neutral hydrogen clouds are found in the MilkyWay and Andromeda halo both as large complexes and smaller isolated clouds. Here we present a search for Hi clouds in the halo of M 33, the third spiral galaxy of the Local Group.
Methods. We have used two complementary data sets: a 3◦ × 3◦ map of the area provided by the Arecibo Legacy Fast ALFA
(ALFALFA) survey and deeper pointed observations carried out with the Arecibo telescope in two fields that permit sampling of the northeastern and southwestern edges of the Hi disc.
Results. The total amount of Hi around M 33 detected by our survey is about 107 M. At least 50% of this mass is made of Hi clouds that are related both in space and velocity to the galaxy. We discuss several scenarios for the origin of these clouds focusing on the two most interesting ones: (a) dark-matter dominated gaseous satellites, (b) debris from filaments flowing into M 33 from the intergalactic medium or generated by a previous interaction with M 31. Both scenarios seem to fit with the observed cloud properties.
Some structures are found at anomalous velocities, particularly an extended Hi complex previously detected by Thilker et al. (2002). Even though the ALFALFA observations seem to indicate that this cloud is possibly connected to M 33 by a faint gas bridge, we cannot firmly establish its extragalactic nature or its relation to M 33.
Conclusions. Taking into account that the clouds associated with M 33 are likely to be highly ionised by the extragalactic ultraviolet (UV) radiation, we predict that the total gas mass associated with them is ≥5 × 107 M. If the gas is steadily falling towards the M 33 disc it can provide the fuel needed to sustain a current star formation rate of 0.5 M yr−1.

Aims. Neutral hydrogen clouds are found in the MilkyWay and Andromeda halo both as large complexes and smaller isolated clouds. Here we present a search for Hi clouds in the halo of M 33, the third spiral galaxy of the Local Group.
Methods. We have used two complementary data sets: a 3◦ × 3◦ map of the area provided by the Arecibo Legacy Fast ALFA
(ALFALFA) survey and deeper pointed observations carried out with the Arecibo telescope in two fields that permit sampling of the northeastern and southwestern edges of the Hi disc.
Results. The total amount of Hi around M 33 detected by our survey is about 107 M. At least 50% of this mass is made of Hi clouds that are related both in space and velocity to the galaxy. We discuss several scenarios for the origin of these clouds focusing on the two most interesting ones: (a) dark-matter dominated gaseous satellites, (b) debris from filaments flowing into M 33 from the intergalactic medium or generated by a previous interaction with M 31. Both scenarios seem to fit with the observed cloud properties.
Some structures are found at anomalous velocities, particularly an extended Hi complex previously detected by Thilker et al. (2002). Even though the ALFALFA observations seem to indicate that this cloud is possibly connected to M 33 by a faint gas bridge, we cannot firmly establish its extragalactic nature or its relation to M 33.
Conclusions. Taking into account that the clouds associated with M 33 are likely to be highly ionised by the extragalactic ultraviolet (UV) radiation, we predict that the total gas mass associated with them is ≥5 × 107 M. If the gas is steadily falling towards the M 33 disc it can provide the fuel needed to sustain a current star formation rate of 0.5 M yr−1.

Citations

27 citations in Web of Science®
25 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

13 downloads since deposited on 11 Mar 2009
7 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute for Computational Science
Dewey Decimal Classification:530 Physics
Language:English
Date:August 2008
Deposited On:11 Mar 2009 14:14
Last Modified:05 Apr 2016 13:06
Publisher:EDP Sciences
ISSN:0004-6361
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:10.1051/0004-6361:200810220
Permanent URL: http://doi.org/10.5167/uzh-16567

Download

[img]Filetype: PDF (Verlags-PDF) - Registered users only
Size: 2MB
View at publisher

[img]
Preview
Content: Accepted Version
Filetype: PDF
Size: 1MB

TrendTerms

TrendTerms displays relevant terms of the abstract of this publication and related documents on a map. The terms and their relations were extracted from ZORA using word statistics. Their timelines are taken from ZORA as well. The bubble size of a term is proportional to the number of documents where the term occurs. Red, orange, yellow and green colors are used for terms that occur in the current document; red indicates high interlinkedness of a term with other terms, orange, yellow and green decreasing interlinkedness. Blue is used for terms that have a relation with the terms in this document, but occur in other documents.
You can navigate and zoom the map. Mouse-hovering a term displays its timeline, clicking it yields the associated documents.

Author Collaborations