J/ApJ/802/30 NGVS VI. Ultra-compact dwarfs in M87 (Zhang+, 2015)
The Next Generation Virgo cluster Survey.
VI. The kinematics of ultra-compact dwarfs and globular clusters in M87.
Zhang H.-X., Peng E.W., Cote P., Liu C., Ferrarese L., Cuillandre J.-C.,
Caldwell N., Gwyn S.D.J., Jordan A., Lancon A., Li B., Munoz R.P.,
Puzia T.H., Bekki K., Blakeslee J.P., Boselli A., Drinkwater M.J.,
Duc P.-A., Durrell P., Emsellem E., Firth P., Sanchez-Janssen R.
<Astrophys. J., 802, 30 (2015)>
=2015ApJ...802...30Z 2015ApJ...802...30Z
ADC_Keywords: Galaxies, spectra ; Photometry, ugriz ; Radial velocities ;
Morphology
Keywords: galaxies: clusters: individual: Virgo; galaxies: dwarf;
galaxies: elliptical and lenticular, cD; galaxies: halos;
galaxies: star clusters: general; globular clusters: general
Abstract:
The origin of ultra-compact dwarfs (UCDs; rh≳10pc) --objects larger
and more massive than typical globular clusters (GCs), but more
compact than typical dwarf galaxies-- has been hotly debated in the
15yrs since their discovery. Even whether UCDs should be considered
galactic in origin, or simply the most extreme star clusters, is not
yet settled. We present the dynamical properties of 97
spectroscopically confirmed UCDs and 911 GCs associated with the
central cD galaxy of the Virgo cluster, M87. Our UCDs, of which 89%
have M*≳2x106M☉ and 92% are as blue as the classic blue
GCs, nearly triple the confirmed sample of Virgo UCDs, providing by
far the best opportunity for studying global dynamics of a UCD system.
We found that (1) UCDs have a surface number density profile that is
shallower than that of blue GCs in the inner ∼70kpc and as steep as
that of red GCs at larger radii; (2) UCDs exhibit a significantly
stronger rotation than GCs, and blue GCs seem to have a velocity field
that is more consistent with that of the surrounding dwarf ellipticals
than with that of UCDs; (3) UCDs have an orbital anisotropy profile
that is tangentially biased at radii ≲40kpc and radially biased
farther out, whereas blue GCs become more tangentially biased at
larger radii beyond ∼40kpc; (4) GCs with M*≳2x106M☉ have
rotational properties indistinguishable from the less massive ones,
suggesting that it is the size, instead of mass, that differentiates
UCDs from GCs as kinematically distinct populations. We conclude 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 "tidally threshed dwarf galaxy" scenario.
Description:
We compiled a sample of spectroscopically confirmed UCDs from three
different sources, i.e., our recently finished 2dF/AAOmega AAT and
Hectospec/MMT surveys, and the radial velocity catalogs of Virgo GCs
and UCDs compiled by Strader et al. (2011, J/ApJS/197/33). For
duplicate observations among the three sources, a weighted average of
the individual radial velocities will be used in this work.
We have carried out (March 28 to April 1 in 2012) a systematic
spectroscopic survey of compact stellar systems (GCs and UCDs) toward
the central regions of the Virgo cluster (Virgo A subcluster), using
the 2dF/AAOmega multi-fiber spectrograph on the AAT. The observations
cover a wavelength range from ∼3700Å to 8800Å, with a resolution
of R=1300.
In 2009 and 2010, we used the Hectospec multifiber spectrograph on the
6.5m MMT telescope to carry out an extensive spectroscopic survey
(3650-9200Å, R=1000) of the central 2°x2° around M87.
The photometric data for the spectroscopic samples are from the NGVS
(Next Generation Virgo Survey; Ferrarese et al. 2012ApJS..200....4F 2012ApJS..200....4F).
The Next Generation Virgo Cluster Survey (NGVS) is a program that uses
the 1deg2 MegaCam instrument on the Canada-France-Hawaii Telescope
to carry out a comprehensive optical imaging survey of the Virgo
cluster, from its core to its virial radius --covering a total area of
104deg2-- in the u*griz bandpasses.
In addition, we have obtained deep Ks-band imaging data for this
region (NGVS-IR; Munoz et al. 2014ApJS..210....4M 2014ApJS..210....4M).
The sample of globular clusters (GCs) has been recently used by Zhu et
al. (2014ApJ...792...59Z 2014ApJ...792...59Z) to determine the dynamical mass profile of
M87. The full catalog of GCs will be presented elsewhere (E. W. Peng
et al. 2015, in preparation).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 126 97 Ultra-compact dwarfs from the Next Generation
Virgo cluster Survey (NGVS)
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See also:
J/MNRAS/443/1151 : AIMSS Project. I. (Norris+, 2014)
J/MNRAS/428/389 : SLUGGS GCs in early-type galaxies (Pota+, 2013)
J/ApJ/748/29 : Spectroscopy of M87 globular clusters (Romanowsky+, 2012)
J/ApJS/197/33 : The M87 globular cluster system (Strader+, 2011)
J/AJ/142/199 : Sizes and luminosities of stellar systems (Brodie+, 2011)
J/ApJ/737/86 : UCD galaxies in the Coma cluster (Chiboucas+, 2011)
J/A+A/531/A4 : Ultra compact dwarfs and globulars in Hya I (Misgeld+, 2011)
J/AJ/137/4956 : Globular clusters around NGC 1407 (Romanowsky+, 2009)
J/ApJS/182/216 : Surface photometry of Virgo ellipticals (Kormendy+, 2009)
J/ApJS/180/54 : GC candidates in ACS Virgo survey. (Jordan+, 2009)
J/AJ/136/2295 : Ultra-compact dwarf candidates in ACO S0740 (Blakeslee+, 2008)
J/ApJ/660/1186 : VCC galaxies classification with SDSS (Lisker+, 2007)
J/ApJ/655/144 : ACS Virgo Cluster Survey. XIII. (Mei+, 2007)
J/ApJS/164/334 : ACS Virgo Cluster Survey. VI (Ferrarese+, 2006)
J/ApJ/613/279 : ACS Virgo Cluster Survey. III. M87 (Jordan+, 2004)
J/ApJ/559/812 : Globular cluster system in M87 (Hanes+, 2001)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Set [on] o=old or n=new sample (1)
3- 11 A9 --- ID Ultra-compact dwarf (UCD) galaxy name
13- 21 F9.5 deg RAdeg Right ascension in decimal degrees (J2000)
23- 30 F8.5 deg DEdeg Declination in decimal degrees (J2000)
32- 35 I4 km/s HRV [556/2419] Heliocentric radial velocity (Vlos)
37- 39 I3 km/s e_HRV [2/140] HRV uncertainty
41- 45 F5.2 mag u*mag [19.7/24]? CFHT/Megacam u* band AB magnitude (2)
47- 50 F4.2 mag e_u*mag [0/0.03]? u*mag uncertainty
52- 56 F5.2 mag gmag [18.4/23] CFHT/Megacam g-band AB magnitude (2)
58- 61 F4.2 mag e_gmag [0/0.01]? gmag uncertainty
63- 67 F5.2 mag rmag [17.9/22.6]? CFHT/Megacam r-band AB magnitude (2)
69- 72 F4.2 mag e_rmag [0/0.01]? rmag uncertainty
74- 78 F5.2 mag imag [17.5/22.3] CFHT/Megacam i-band AB magnitude (2)
80- 83 F4.2 mag e_imag [0/0.02]? imag uncertainty
85- 89 F5.2 mag zmag [17.3/22.3]? CFHT/Megacam z-band AB magnitude (2)
91- 94 F4.2 mag e_zmag [0/0.03]? zmag uncertainty
96-100 F5.2 mag Ksmag [17.1/22.4]? CFHT/WIRCam Ks-band AB magnitude (2)
102-105 F4.2 mag e_Ksmag [0/0.05]? Ksmag uncertainty
107-111 F5.3 mag E(B-V) [0.02/0.04] Galactic reddening determined by
Schlegel et al. (1998ApJ...500..525S 1998ApJ...500..525S)
113-116 F4.1 pc rh [0.6/40.2]? Half-light radius measured on NGVS
images
118-120 F3.1 pc e_rh [0.1/8.4]? rh uncertainty
122-126 F5.1 pc rhHST [9.7/100.6]? Half-light radius measured on HST
images (3)
--------------------------------------------------------------------------------
Note (1): The UCDs in the old sample have been compiled by Brodie et al.
(2011, J/AJ/142/199). In addition, g- and i-band photometry for
H30772 and S887 is from Brodie et al. (2011, J/AJ/142/199).
Note (2): MegaCam u*griz five-band and WIRCam Ks-band 3" diameter AB magnitudes
(not corrected for Galactic extinction).
Note (3): rh,HST measures from Jordan et al. (2005ApJ...634.1002J 2005ApJ...634.1002J,
2009, J/ApJS/180/54) and Strader et al. (2011, J/ApJS/197/33)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Ferrarese et al. Paper I. 2012ApJS..200....4F 2012ApJS..200....4F
Paudel et al. Paper IV. 2013ApJ...767..133P 2013ApJ...767..133P
Zhu et al. Paper V. 2014ApJ...792...59Z 2014ApJ...792...59Z
Zhang et al. Paper VI. 2015ApJ...802...30Z 2015ApJ...802...30Z This Catalog
Sanchez-Janssen et al. Paper VII. 2016ApJ...820...69S 2016ApJ...820...69S
Durrell et al. Paper VIII. 2014ApJ...794..103D 2014ApJ...794..103D
Grossauer et al. Paper IX. 2015ApJ...807...88G 2015ApJ...807...88G
Liu et al. Paper X. 2015ApJ...812...34L 2015ApJ...812...34L Cat. J/ApJ/812/34
Raichoor et al. Paper XI. 2014ApJ...797..102R 2014ApJ...797..102R
Guerou et al. Paper XII. 2015ApJ...804...70G 2015ApJ...804...70G
Ferrarese et al. Paper XIII. 2016ApJ...824...10F 2016ApJ...824...10F
Ferrarese et al. Paper XIV. 2020ApJ...890..128F 2020ApJ...890..128F Cat. J/ApJ/890/128
Raichoor et al. Paper XV. 2014ApJ...797..102R 2014ApJ...797..102R
Toloba et al. Paper XVI. 2016ApJ...822...51T 2016ApJ...822...51T
Sun et al. Paper XVII. 2019ApJ...885..145S 2019ApJ...885..145S
Cantiello et al. Paper XVIII. 2018ApJ...856..126C 2018ApJ...856..126C
Lokhorst et al. Paper XIX. 2016ApJ...819..124L 2016ApJ...819..124L
Licitra et al. Paper XX. 2016ApJ...829...44L 2016ApJ...829...44L Cat. J/ApJ/829/44
Parroni et al. Paper XXI. 2017ApJ...848..114P 2017ApJ...848..114P
Paudel et al. Paper XXII. 2017ApJ...834...66P 2017ApJ...834...66P
Sanchez-Janssen et al. Paper XXIII. 2019ApJ...878...18S 2019ApJ...878...18S Cat. J/ApJ/878/18
Roediger et al. Paper XXIV. 2017ApJ...836..120R 2017ApJ...836..120R
Powalka et al. Paper XXV. 2016ApJS..227...12P 2016ApJS..227...12P Cat. J/ApJS/227/12
Powalka et al. Paper XXVI. 2017ApJ...844..104P 2017ApJ...844..104P
Fantin et al. Paper XXVIII. 2017ApJ...843...53F 2017ApJ...843...53F
Lim et al. Paper XXX. 2020ApJ...899...69L 2020ApJ...899...69L
Longobardi et al. Paper XXXI. 2018ApJ...864...36L 2018ApJ...864...36L
Powalka et al. Paper XXXII. 2018ApJ...856...84P 2018ApJ...856...84P
Liu et al. Paper XXXIV. 2020ApJS..250...17L 2020ApJS..250...17L Cat. J/ApJS/250/17
(End) Emmanuelle Perret [CDS] 21-Jul-2015