J/MNRAS/429/2264 Galaxies in the UMa cluster complex (Karachentsev+, 2013)
Anatomy of Ursa Majoris.
Karachentsev I.D., Nasonova O.G., Courtois H.M.
<Mon. Not. R. Astron. Soc., 429, 2264-2273 (2013)>
=2013MNRAS.429.2264K 2013MNRAS.429.2264K
ADC_Keywords: Galaxies, nearby ; Clusters, galaxy ; Morphology ; Redshifts
Keywords: galaxies: distances and redshifts - cosmological parameters -
large-scale structure of Universe
Abstract:
A nearby friable cloud in Ursa Majoris contains 270 galaxies with
radial velocities 500<VLG<1500km/s inside the area of
RA=[11.0h,13.0h] and DE=[+40°,+60°]. At present, 97 galaxies
of them have individual distance estimates. We use these data to
clarify the structure and kinematics of the UMa complex. According to
Makarov & Karachentsev (2011MNRAS.412.2498M 2011MNRAS.412.2498M, Cat. J/MNRAS/412/2498),
most of the UMa galaxies belong to seven bound groups, which have the
following median parameters: velocity dispersion of 58k/s, harmonic
projected radius of 300kpc, virial mass of 2x1012M☉ and virial
mass-to-K-band luminosity ratio of 27M☉/L☉. Almost a half of
the UMa cloud population are gas-rich dwarfs (Ir, Im, BCD) with active
star formation seen in the GALEX UV-survey. The UMa groups reside
within 15-19Mpc from us, being just at the same distance as the Virgo
cluster. The total virial mass of the UMa groups is 4x1013M☉,
yielding the average density of dark matter in the UMa cloud to be
Ωm=0.08, i.e. a factor of 3 lower than the cosmic average. This
is despite the fact that the UMa cloud resides in a region of the
Universe that is an apparent overdensity. A possible explanation for
this is that most mass in the Universe lies in the empty space between
clusters. Herewith, the mean distances and velocities of the UMa
groups follow nearly undisturbed Hubble flow without a sign of the
'Z-wave' effect caused by infall towards a massive attractor. This
constrains the total amount of dark matter between the UMa groups
within the cloud volume.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 66 270 List of 270 galaxies within α=[11.0h,13.0h],
δ=[+40,+60°] and VLG=[500-1500]km/s
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See also:
J/MNRAS/412/2498 : Galaxy groups & clouds in local universe (Makarov+, 2011)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Galaxy name (2MASX names are truncated)
17- 18 I2 h RAh Right ascension (J2000)
20- 21 I2 min RAm Right ascension (J2000)
23- 26 F4.1 s RAs Right ascension (J2000)
28 A1 --- DE- Declination sign (J2000)
29- 30 I2 deg DEd Declination (J2000)
32- 33 I2 arcmin DEm Declination (J2000)
35- 36 I2 arcsec DEs Declination (J2000)
38- 41 I4 km/s VLG [509/1497] Radial velocity in Local Group frame
43- 44 I2 --- TType [-5/10] T Type morphology
46- 49 F4.1 mag Ksmag [5.5/19.9] Integral apparent 2MASS Ks magnitude
51- 55 A5 --- Group Name of the brightest galaxy in the MK group
57- 61 F5.2 mag MOD [28.8/32.8]? Distance modulus (m-M)
63- 66 F4.1 Mpc Dist [5.8/36.1]? Distance
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 30-Apr-2015