Origin of ultra-compact dwarfs: a dynamical perspective

Zhang, Hong-Xin, Peng, Eric W., Cote, Patrick, Liu, Chengze, Ferrarese, Laura, Cuillandre, Jean-Charles, Caldwell, Nelson, Gwyn, Stephen D. J., Jordan, Andres, Lancon, Ariane, Li, Biao, Munoz, Roberto P., Puzia, Thomas H., Bekki, Kenji, Blakeslee, John, Boselli, Alessandro, Drinkwater, Michael J., Duc, Pierre-Alain, Durrell, Patrick, Emsellem, Eric, Firth, Peter and Sanchez-Janssen, Ruben (2016). Origin of ultra-compact dwarfs: a dynamical perspective. In: IAU Symposium 312 : Star Clusters and Black Holes in Galaxies across Cosmic Time, Beijing, China, (264-268). 25-29 August 2014. doi:10.1017/S1743921315008005

Author Zhang, Hong-Xin
Peng, Eric W.
Cote, Patrick
Liu, Chengze
Ferrarese, Laura
Cuillandre, Jean-Charles
Caldwell, Nelson
Gwyn, Stephen D. J.
Jordan, Andres
Lancon, Ariane
Li, Biao
Munoz, Roberto P.
Puzia, Thomas H.
Bekki, Kenji
Blakeslee, John
Boselli, Alessandro
Drinkwater, Michael J.
Duc, Pierre-Alain
Durrell, Patrick
Emsellem, Eric
Firth, Peter
Sanchez-Janssen, Ruben
Title of paper Origin of ultra-compact dwarfs: a dynamical perspective
Conference name IAU Symposium 312 : Star Clusters and Black Holes in Galaxies across Cosmic Time
Conference location Beijing, China
Conference dates 25-29 August 2014
Convener International Astronomical Union
Journal name Proceedings of the International Astronomical Union   Check publisher's open access policy
Series IAU Symposium
Place of Publication Cambridge, United Kingdom
Publisher Cambridge University Press
Publication Year 2016
Year available 2016
Sub-type Fully published paper
DOI 10.1017/S1743921315008005
Open Access Status Not Open Access
ISSN 1743-9221
Volume 10
Start page 264
End page 268
Total pages 5
Chapter number 64
Total chapters 69
Collection year 2017
Language eng
Formatted Abstract/Summary
Discovery of ultra-compact dwarfs (UCDs) in the past 15 years blurs the once thought clear division between classic globular clusters (GCs) and early-type galaxies. The intermediate nature of UCDs, which are larger and more massive than typical GCs but more compact than typical dwarf galaxies, has triggered hot debate on whether UCDs should be considered galactic in origin or merely the most extreme GCs. Previous studies of various scaling relations, stellar populations and internal dynamics did not give an unambiguous answer to the primary origin of UCDs. In this contribution, we present the first ever detailed study of global dynamics of 97 UCDs (rh ≳ 10 pc) associated with the central cD galaxy of the Virgo cluster, M87. We found that UCDs follow a different radial number density profile and different rotational properties from GCs. The orbital anisotropies of UCDs are tangentially-biased within ~ 40 kpc of M87 and become radially-biased with radius further out. In contrast, the blue GCs, which have similar median colors to our sample of UCDs, become more tangentially-biased at larger radii beyond ~ 40 kpc. Our analysis suggests that most UCDs in M87 are not consistent with being merely the most luminous and extended examples of otherwise normal GCs. The radially-biased orbital structure of UCDs at large radii is in general agreement with the scenario that most UCDs originated from the tidally threshed dwarf galaxies.
Keyword Galaxies: clusters
Globular clusters
Galaxies: nuclei
Galaxies: elliptical and lenticular
Galaxies: kinematics and dynamics
Q-Index Code E1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Conference Paper
Collections: School of Mathematics and Physics
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