The SAMI Galaxy Survey: kinematics of dusty early-type galaxies

Creators: Bassett, R.; Bekki, K.; Cortese, L.; Couch, W. J.; Sansom, A. E.; van de Sande, J.; Bryant, J. J.; Foster, C.; Croom, S. M.; Brough, S.; Sweet, S. M.; Medling, A. M.; Owers, M. S.; Driver, S. P.; Davies, L. J. M.; Wong, O. I.; Groves, B. A.; Bland-Hawthorn, J.; Richards, S. N.; Goodwin, M.; Konstantopoulos, I. S.; Lawrence, J. S.

Abstract

Recently, large samples of visually classified early-type galaxies (ETGs) containing dust have been identified using space-based infrared observations with the Herschel Space Telescope. The presence of large quantities of dust in massive ETGs is peculiar as X-ray haloes of these galaxies are expected to destroy dust in ∼10^7 yr (or less). This has sparked a debate regarding the origin of the dust: Is it internally produced by asymptotic giant branch stars, or is it accreted externally through mergers? We examine the 2D stellar and ionized gas kinematics of dusty ETGs using integral field spectroscopy observations from the SAMI Galaxy Survey, and integrated star formation rates, stellar masses and dust masses from the GAMA survey. Only 8 per cent (4/49) of visually classified ETGs are kinematically consistent with being dispersion-supported systems. These 'dispersion-dominated galaxies' exhibit discrepancies between stellar and ionized gas kinematics, either offsets in the kinematic position angle or large differences in the rotational velocity, and are outliers in star formation rate at a fixed dust mass compared to normal star-forming galaxies. These properties are suggestive of recent merger activity. The remaining ∼90 per cent of dusty ETGs have low velocity dispersions and/or large circular velocities, typical of 'rotation-dominated galaxies'. These results, along with the general evidence of published works on X-ray emission in ETGs, suggest that they are unlikely to host hot, X-ray gas consistent with their low M* when compared to dispersion-dominated galaxies. This means that dust will be long-lived and thus these galaxies do not require external scenarios for the origin of their dust content.

Additional Information

© 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2017 April 21. Received 2017 April 14; in original form 2016 December 11. Published: 03 May 2017. RB acknowledges support under the Australian Research Council's (ARC) Discovery Projects funding scheme (DP130100664). JvdS is funded under Bland-Hawthorn's ARC Laureate Fellowship (FL140100278). SMC acknowledges the support of an Australian Research Council Future Fellowship (FT100100457). SB acknowledges the funding support from the Australian Research Council through a Future Fellowship (FT140101166). Support for AMM is provided by NASA through a Hubble Fellowship grant #HST-HF2-51377 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. MSO acknowledges the funding support from the Australian Research Council through a Future Fellowship Fellowship (FT140100255). We would also like to thank the anonymous referee for comments and suggestions that have improved the clarity and readability of this work. The SAMI Galaxy Survey is based on observations made at the Anglo-Australian Telescope. SAMI was developed jointly by the University of Sydney and the Australian Astronomical Observatory. The SAMI input catalogue is based on data taken from the SDSS, the GAMA Survey and the VST ATLAS Survey. The SAMI Galaxy Survey is funded by the Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO), through project number CE110001020, and other participating institutions. The SAMI Galaxy Survey website is http://sami-survey.org/. GAMA is a joint European–Australasian project based around a spectroscopic campaign using the Anglo-Australian Telescope. The GAMA input catalogue is based on data taken from the SDSS and the UKIRT Infrared Deep Sky Survey. Complementary imaging of the GAMA regions is being obtained by a number of independent survey programmes, including GALEX MIS, VST KiDS, VISTA VIKING, WISE, H-ATLAS, GMRT and ASKAP providing UV to radio coverage. GAMA is funded by the STFC (UK), the ARC (Australia), the AAO and the participating institutions. The GAMA website is http://www.gama-survey.org/.

Attached Files

Published - stx1000.pdf

Submitted - 1704.08433.pdf

Files

1704.08433.pdf

Files (4.4 MB)

Name	Size	Download all
1704.08433.pdf md5:4f41d8f0f9c22d9737f1fac1523e6af1	1.5 MB	Preview Download
stx1000.pdf md5:5d8f9fec8ca8e37fd38d42f59bc093bb	2.9 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes