Kinematics of dwarf galaxies in gas-rich groups, and the survival and detectability of tidal dwarf galaxies

Sweet, Sarah M., Drinkwater, Michael J., Meurer, Gerhardt, Kilborn, Virginia, Audcent-Ross, Fiona, Baumgardt, Holger and Bekki, Kenji (2016) Kinematics of dwarf galaxies in gas-rich groups, and the survival and detectability of tidal dwarf galaxies. Monthly Notices of the Royal Astronomical Society, 455 3: 2508-2528. doi:10.1093/mnras/stv2480

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Author Sweet, Sarah M.
Drinkwater, Michael J.
Meurer, Gerhardt
Kilborn, Virginia
Audcent-Ross, Fiona
Baumgardt, Holger
Bekki, Kenji
Title Kinematics of dwarf galaxies in gas-rich groups, and the survival and detectability of tidal dwarf galaxies
Journal name Monthly Notices of the Royal Astronomical Society   Check publisher's open access policy
ISSN 0035-8711
Publication date 2016-01-21
Year available 2015
Sub-type Article (original research)
DOI 10.1093/mnras/stv2480
Open Access Status File (Publisher version)
Volume 455
Issue 3
Start page 2508
End page 2528
Total pages 21
Place of publication Oxford, United Kingdom
Publisher Oxford University Press
Collection year 2016
Language eng
Formatted abstract
We present DEIMOS multi-object spectroscopy (MOS) of 22 star-forming dwarf galaxies located in four gas-rich groups, including six newly discovered dwarfs. Two of the galaxies are strong tidal dwarf galaxy (TDG) candidates based on our luminosity–metallicity relation definition. We model the rotation curves of these galaxies. Our sample shows low mass-to-light ratios (M/L = 0.73 ± 0.39 M/L) as expected for young, star-forming dwarfs. One of the galaxies in our sample has an apparently strongly falling rotation curve, reaching zero rotational velocity outside the turnover radius of rturn = 1.2re. This may be (1) a polar ring galaxy, with a tilted bar within a face-on disc; (2) a kinematic warp. These scenarios are indistinguishable with our current data due to limitations of slit alignment inherent to MOS-mode observations. We consider whether TDGs can be detected based on their tidal radius, beyond which tidal stripping removes kinematic tracers such as Hα emission. When the tidal radius is less than about twice the turnover radius, the expected falling rotation curve cannot be reliably measured. This is problematic for as much as half of our sample, and indeed more generally, galaxies in groups like these. Further to this, the Hα light that remains must be sufficiently bright to be detected; this is only the case for three (14 per cent) galaxies in our sample. We conclude that the falling rotation curves expected of TDGs are intrinsically difficult to detect.
Keyword Galaxies: abundances
Galaxies: dwarf
Galaxies: groups: general
Galaxies: interactions
Galaxies: kinematics and dynamics
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ
Additional Notes Published online 23 November 2015

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mathematics and Physics
Official 2016 Collection
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Citation counts: TR Web of Science Citation Count  Cited 1 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 1 times in Scopus Article | Citations
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