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A Herschel*-ATLAS study of dusty spheroids: Probing the minor-merger process in the local Universe

Citation

Kaviraj, S and Rowlands, K and Alpaslan, M and Dunne, L and Ting, YS and Bureau, M and Shabala, S and Lintott, CJ and Smith, DJB and Agius, N and Auld, R and Baes, M and Bourne, N and Cava, A and Clements, DL and Cooray, A and Dariush, A and De Zotti, G and Driver, SP and Eales, S and Hopwood, R and Hoyos, C and Ibar, E and Maddox, S and Michalowski, MJ and Sansom, AE and Smith, M and Valiante, E, A Herschel*-ATLAS study of dusty spheroids: Probing the minor-merger process in the local Universe, Monthly Notices of the Royal Astronomical Society, 435, (2) pp. 1463-1468. ISSN 0035-8711 (2013) [Refereed Article]

Copyright Statement

Copyright 2013 the authors

DOI: doi:10.1093/mnras/stt1629

Abstract

We use multiwavelength (0.12–500 μm) photometry from Herschel-ATLAS, WISE, UKIDSS, SDSS and GALEX to study 23 nearby spheroidal galaxies with prominent dust lanes (DLSGs). DLSGs are considered to be remnants of recent minor mergers, making them ideal laboratories for studying both the interstellar medium (ISM) of spheroids and minor-merger-driven star formation in the nearby Universe. The DLSGs exhibit star formation rates (SFRs) between 0.01 and 10 M yr−1, with a median of 0.26 M yr−1 (a factor of 3.5 greater than the average SG). The median dust mass, dust-to-stellar mass ratio and dust temperature in these galaxies are around 107.6 M, ≈0.05 per cent and ≈19.5 K, respectively. The dust masses are at least a factor of 50 greater than that expected from stellar mass loss and, like the SFRs, show no correlation with galaxy luminosity, suggesting that both the ISM and the star formation have external drivers. Adopting literature gas-to-dust ratios and star formation histories derived from fits to the panchromatic photometry, we estimate that the median current and initial gas-to-stellar mass ratios in these systems are ≈4 and ≈7 per cent, respectively. If, as indicated by recent work, minor mergers that drive star formation in spheroids with (NUV − r) > 3.8 (the colour range of our DLSGs) have stellar mass ratios between 1:6 and 1:10, then the satellite gas fractions arelikely ≥50 per cent.

Item Details

Item Type:Refereed Article
Keywords:galaxies: elliptical and lenticular, cD galaxies: evolution galaxies: formation galaxies: interactions galaxies: ISM
Research Division:Physical Sciences
Research Group:Astronomical and Space Sciences
Research Field:Galactic Astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Physical Sciences
Author:Shabala, S (Dr Stas Shabala)
ID Code:87025
Year Published:2013
Web of Science® Times Cited:7
Deposited By:Mathematics and Physics
Deposited On:2013-11-06
Last Modified:2014-04-04
Downloads:0

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