Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/208728

Title

The intriguing Hi gas in NGC 5253: an infall of a diffuse, low-metallicity Hi cloud?

Author(s)

Lopez-Sanchez, A. R.;  Koribalski, B. S.;  Van Eymeren, J.;  Esteban, C.;  Kirby, E.;  Jerjen, H.;  Lonsdale, N.

Abstract

We present new, deep Hi line and 20-cm radio-continuum data of the very puzzling blue compact dwarf galaxy NGC 5253, obtained with the Australia Telescope Compact Array as part of the 'Local Volume Hi Survey' (LVHIS). Our low-resolution Hi maps show, for the first time, the disturbed Hi morphology that NGC 5253 possesses, including tails, plumes and detached Hi clouds. The high-resolution map reveals an Hi plume at the SE and an Hi structure at the NW that surrounds an H-alpha shell. This latter structure is related to an expanding bubble in the interstellar medium (ISM), but it will almost certainly not originate a galactic wind. We confirm that the kinematics of the neutral gas in NGC 5253 are highly perturbed and do not follow a rotation pattern. We discuss the outflow and infall scenarios to explain such disturbed kinematics, analyse the environment in which NGC 5253 resides and compare its properties with those observed in similar star-forming dwarf galaxies. The radio-continuum emission of NGC 5253 is resolved and associated with the intense star-forming region located at the centre of the galaxy. We complete the analysis using multiwavelength data extracted from the literature, which include X-ray, Galaxy Evolution Explorer (GALEX) far-ultraviolet, optical B and R band and H-alpha, near-infrared H band, and far-infrared data. We estimate the star formation rate using this multiwavelength approach, and compare the results with other galaxy properties. NGC 5253 does not satisfy the Schmidt-Kennicutt law of star formation, has a very low Hi mass-to-light ratio when comparing with its stellar mass and seems to be slightly metal-deficient in comparison with starbursts of similar baryonic mass. Taking into account all available multiwavelength data, we conclude that NGC 5253 is probably experiencing the infall of a diffuse, low-metallicity Hi cloud along the minor axis of the galaxy. The infall of this independent Hi cloud is comprising the ISM and triggering the powerful starburst we see in NGC 5253. The tidally disturbed material observed at the east and north of the galaxy is a consequence of this interaction, which probably started more than 100 Myr ago. The origin of this Hi cloud may be related with a strong interaction between NGC 5253 and the late-type spiral galaxy M83 in the past.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing

Source

Monthly Notices of the Royal Astronomical Society, Vol. 419, no. 2 (Jan 2012), pp. 1051-1069

Publication year

2012

FOR Code(s)

0201 Astronomical and Space Sciences

Keyword(s)

Abundances;  NGC 5264;  Galaxy interactions;  Galaxy kinematics and dynamics;  ISM;  Starburst galaxies

Publisher

Wiley-Blackwell

ISSN

0035-8711

Publisher URL

http://dx.doi.org/10.1111/j.1365-2966.2011.19762.x

Copyright

Copyright © 2011 The Authors. Journal copyright © 2011 Royal Astronomical Society.

Additional information

This research has made extensive use of the SAO/NASA Astrophysics Data System Bibliographic Services (ADS). This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation.

Peer reviewed