scholarly journals Structure of the Canes Venatici I cloud of galaxies

2014 ◽  
Vol 11 (S308) ◽  
pp. 209-210
Author(s):  
Dmitry I. Makarov ◽  
Lidia N. Makarova ◽  
Roman I. Uklein
Keyword(s):  
Total Mass ◽  
Local Group ◽  
Homogeneous Sample ◽  
Chaotic Motions ◽  
Groups Of Galaxies ◽  
System A ◽  
Central Galaxy ◽  
Luminous Matter ◽  
Red Giant ◽  
Centaurus A

AbstractWe study the spatial distribution of the sparse cloud of galaxies in the Canes Venatici constellation. We determined distances of 30 galaxies using the tip of the red giant branch (TRGB) method. This homogeneous sample allows us to distinguish the zone of chaotic motions around the center of the system. A group of galaxies around M94 is characterized by the mass-luminosity ratio of M/LB=159 (M/L)⊙. It is significantly higher than the typical ratio M/LB=159 (M/L)⊙ for the nearby groups of galaxies. The CVn I cloud of galaxies contains 4–5 times less luminous matter compared with the well-known nearby groups, such as the Local Group, M 81 and Centaurus A. The central galaxy M 94 is at least 1 mag fainter than any other central galaxy of these groups. However, the concentration of galaxies in the Canes Venatici may have a comparable total mass.

scholarly journals Dwarf Elliptical Galaxies in the M81 Group: The Structure and Stellar Populations of BK5N and F8D1

1998 ◽  
Vol 11 (1) ◽  
pp. 132-133
Author(s):  
Taft E. Armandroff ◽  
Nelson Caldwell ◽  
G.S. Da Costa ◽  
Patrick Seitzer
Keyword(s):  
Surface Brightness ◽  
Local Group ◽  
Absolute Magnitude ◽  
Groups Of Galaxies ◽  
Central Surface ◽  
Luminous Matter ◽  
Total Magnitude ◽  
Metal Abundance ◽  
The Mean ◽  
Red Giant

The M81 group is one of the nearest groups of galaxies, but its properties are quite different from those of the Local Group. It has therefore provided a different environment for the evolution of its member galaxies. We have carried out a CCD survey of the M81 group to search for analogs to Local Group dwarf elliptical (dE) galaxies. All the M81 dwarfs previously identified in photographic surveys were recovered and we also discovered several new systems whose surface brightnesses fall within the range found for Local Group dE’s. We have obtained HST WFPC2 images through the F555W and F814W filters of two M81 group dE’s: BK5N and a new system, designated F8D1. The resulting color-magnitude diagrams show the upper two magnitudes of the red giant branch. The I magnitudes of the red giant branch tip in both galaxies yield distances that are consistent with membership in the M81 group. Surface brightness and total magnitude measurements indicate that BK5N and F8D1 have similar central surface brightness (24.5 and 25.4 mag arcsec-2 in V, respectively), but F8D1 is larger length scale results in it being 3 magnitudes more luminous than BK5N. BK5N lies on the relation between central surface brightness and absolute magnitude defined by Local Group dwarf ellipticals, but F8D1 does not. F8D1 is more luminous for its central surface brightness than the relation predicts, similar to the large low surface brightness dwarf galaxies found in, for example, Virgo. The mean color of the giant branch is used to establish the mean abundance of each galaxy. F8D1, the more luminous galaxy, is significantly more metal rich ([Fe/H] ≈ -1.0) than BK5N ([Fe/H] ≈ -1.7). Both BK5N and F8D1 lie on the relation between absolute magnitude and metal abundance defined by Local Group dwarf ellipticals. However, as regards the relation between central surface brightness and metal abundance, BK5N again follows the Local Group dwarfs, while F8D1 deviates significantly from this relation. This suggests that the total amount of luminous matter is more fundamental in controlling metal enrichment than the surface density of luminous matter. We have also used the color width of the giant branch compared with the photometric errors to establish abundance ranges in both galaxies, the sizes of which are comparable to those in Local Group dE’s.

Subaru Hyper Suprime-Cam Survey for the Local Group Dwarf Galaxies: Ursa Minor

2018 ◽  
Vol 14 (S344) ◽  
pp. 94-95
Author(s):  
Yutaka Komiyama
Keyword(s):  
Binary Systems ◽  
Main Sequence ◽  
Local Group ◽  
Dwarf Galaxies ◽  
Structural Parameters ◽  
Deep Imaging ◽  
Ursa Minor ◽  
Red Giant

AbstractWe have carried out a wide and deep imaging survey for the Local Group dwarf spheroidal galaxy Ursa Minor (UMi) using Hyper Suprime-Cam (HSC). The data cover out beyond the nominal tidal radius down to ~25 mag in i band, which is ~2 mag below the main sequence turn-off point. The structural parameters of UMi are derived using red giant branch (RGB) stars and sub-giant branch (SGB) stars, and the tidal radius is suggested to be larger than those estimated by the previous studies. It is also found that the distribution of bluer RGB/SGB stars is more extended than that of redder RGB/SGB stars. The fraction of binary systems is estimated to be ~0.4 from the morphology of the main sequences.

scholarly journals The Orientation of Galaxies in Nearby Galaxy Groups

2004 ◽  
Vol 217 ◽  
pp. 116-117
Author(s):  
P. Flin ◽  
M. Biernacka ◽  
J. Krywult
Keyword(s):  
Statistical Analysis ◽  
Milky Way ◽  
Random Distribution ◽  
Local Group ◽  
Dwarf Galaxies ◽  
Nearby Galaxy ◽  
Groups Of Galaxies ◽  
Galaxy Groups ◽  
Isotropic Distribution ◽  
Local Supercluster

The statistical analysis of six nearby groups of galaxies, connected with the Milky Way, M31, M81, M101, NGC5128 and NGC5236 shows an isotropic distribution of galaxy planes, similarly to galaxies within the Local Group. Also planes of galaxies in the nearby (Vr < 500 km s−1) region of the Local Supercluster exhibit random distribution, disregarding their membership to groups. The result shows that strong environmental effects observed among dwarf galaxies do not change generally random distribution of galaxy planes in this region.

scholarly journals OCCASO – III. Iron peak and α elements of 18 open clusters. Comparison with chemical evolution models and field stars

2019 ◽  
Vol 490 (2) ◽  
pp. 1821-1842 ◽  
Author(s):  
L Casamiquela ◽  
S Blanco-Cuaresma ◽  
R Carrera ◽  
L Balaguer-Núñez ◽  
C Jordi ◽  
...  
Keyword(s):  
Chemical Evolution ◽  
Open Cluster ◽  
Dynamical Evolution ◽  
Open Clusters ◽  
Chemical Abundances ◽  
Homogeneous Sample ◽  
Giant Stars ◽  
Stellar Nucleosynthesis ◽  
Solar Abundances ◽  
Red Giant

ABSTRACT The study of open-cluster chemical abundances provides insights on stellar nucleosynthesis processes and on Galactic chemo-dynamical evolution. In this paper we present an extended abundance analysis of 10 species (Fe, Ni, Cr, V, Sc, Si, Ca, Ti, Mg, O) for red giant stars in 18 OCCASO clusters. This represents a homogeneous sample regarding the instrument features, method, line list and solar abundances from confirmed member stars. We perform an extensive comparison with previous results in the literature, and in particular with the Gaia FGK Benchmark stars Arcturus and $\mu$-Leo. We investigate the dependence of [X/Fe] with metallicity, Galactocentric radius (6.5 kpc &lt; RGC &lt; 11 kpc), age (0.3 Gyr &lt; Age &lt; 10 Gyr), and height above the plane (|z| &lt; 1000 pc). We discuss the observational results in the chemo-dynamical framework, and the radial migration impact when comparing with chemical evolution models. We also use APOGEE DR14 data to investigate the differences between the abundance trends in RGC and |z| obtained for clusters and for field stars.

scholarly journals Distance to the nearby dwarf galaxy [TT2009] 25 in the NGC 891 group using the tip of the red giant branch

2019 ◽  
Vol 629 ◽  
pp. L2 ◽  
Author(s):  
Oliver Müller ◽  
Rodrigo Ibata ◽  
Marina Rejkuba ◽  
Lorenzo Posti
Keyword(s):  
Milky Way ◽  
Local Group ◽  
Dwarf Galaxies ◽  
Dwarf Galaxy ◽  
Small Scale ◽  
Accurate Information ◽  
Standard Candle ◽  
Stellar Halo ◽  
Red Giant ◽  
Small Field Of View

Dwarf galaxies are key objects for small-scale cosmological tests like the abundance problems or the planes-of-satellites problem. A crucial task is therefore to get accurate information for as many nearby dwarf galaxies as possible. Using extremely deep, ground-based V and i-band Subaru Suprime Cam photometry with a completeness of i = 27 mag, we measure the distance of the dwarf galaxy [TT2009] 25 using the tip of the red giant branch as a standard candle. This dwarf resides in the field around the Milky Way-analog NGC 891. Using a Bayesian approach, we measure a distance of 10.28−1.73+1.17 Mpc, which is consistent with the distance of NGC 891, and thus confirm it as a member of NGC 891. The dwarf galaxy follows the scaling relations defined by the Local Group dwarfs. We do not find an extended stellar halo around [TT2009] 25. In the small field of view of 100 kpc covered by the survey, only one bright dwarf galaxy and the giant stream are apparent. This is comparable to the Milky Way, where one bright dwarf resides in the same volume, as well as the Sagittarius stream – excluding satellites which are farther away but would be projected in the line-of-sight. It is thus imperative to survey for additional dwarf galaxies in a larger area around NGC 891 to test the abundance of dwarf galaxies and compare this to the number of satellites around the Milky Way.

scholarly journals ON THE PROGENITORS OF LOCAL GROUP NOVAE. II. THE RED GIANT NOVA RATE OF M31

2016 ◽  
Vol 817 (2) ◽  
pp. 143 ◽  
Author(s):  
S. C. Williams ◽  
M. J. Darnley ◽  
M. F. Bode ◽  
A. W. Shafter
Keyword(s):  
Local Group ◽  
Red Giant

scholarly journals The dwarf galaxy satellite system of Centaurus A

2019 ◽  
Vol 629 ◽  
pp. A18 ◽  
Author(s):  
Oliver Müller ◽  
Marina Rejkuba ◽  
Marcel S. Pawlowski ◽  
Rodrigo Ibata ◽  
Federico Lelli ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Local Group ◽  
Dwarf Galaxies ◽  
Dwarf Galaxy ◽  
3D Structure ◽  
Major Axis ◽  
Asymptotic Giant Branch ◽  
Semi Major Axis ◽  
Distance Measurements ◽  
Red Giant

Dwarf galaxy satellite systems are essential probes to test models of structure formation, making it necessary to establish a census of dwarf galaxies outside of our own Local Group. We present deep FORS2 VI band images from the ESO Very Large Telescope (VLT) for 15 dwarf galaxy candidates in the Centaurus group of galaxies. We confirm nine dwarfs to be members of Cen A by measuring their distances using a Bayesian approach to determine the tip of the red giant branch luminosity. We have also fit theoretical isochrones to measure their mean metallicities. The properties of the new dwarfs are similar to those in the Local Group in terms of their sizes, luminosities, and mean metallicities. Within our photometric precision, there is no evidence of a metallicity spread, but we do observe possible extended star formation in several galaxies, as evidenced by a population of asymptotic giant branch stars brighter than the red giant branch tip. The new dwarfs do not show any signs of tidal disruption. Together with the recently reported dwarf galaxies by the complementary PISCeS survey, we study the luminosity function and 3D structure of the group. By comparing the observed luminosity function to the high-resolution cosmological simulation IllustrisTNG, we find agreement within a 90% confidence interval. However, Cen A seems to be missing its brightest satellites and has an overabundance of the faintest dwarfs in comparison to its simulated analogs. In terms of the overall 3D distribution of the observed satellites, we find that the whole structure is flattened along the line-of-sight, with a root-mean-square (rms) height of 130 kpc and an rms semi-major axis length of 330 kpc. Future distance measurements of the remaining dwarf galaxy candidates are needed to complete the census of dwarf galaxies in the Centaurus group.

scholarly journals THE ARAUCARIA PROJECT. INFRARED TIP OF THE RED GIANT BRANCH DISTANCES TO FIVE DWARF GALAXIES IN THE LOCAL GROUP

2011 ◽  
Vol 141 (6) ◽  
pp. 194 ◽  
Author(s):  
Marek Górski ◽  
Grzegorz Pietrzyński ◽  
Wolfgang Gieren
Keyword(s):  
Local Group ◽  
Dwarf Galaxies ◽  
Red Giant

scholarly journals Stellar Populations and Local Group Membership of the Dwarf Galaxy DDO 210

1999 ◽  
Vol 192 ◽  
pp. 268-271
Author(s):  
Myung Gyoon Lee
Keyword(s):  
Stellar Population ◽  
Local Group ◽  
Group Membership ◽  
Dwarf Galaxy ◽  
Stellar Populations ◽  
Young Stars ◽  
Ccd Photometry ◽  
A Value ◽  
Red Giant

Deep BVI CCD photometry of dwarf galaxy DD0 210 obtained in this study shows that the resolved stellar population in this galaxy consists of a dominant old red giant population and some young stars. We have estimated the distance to this galaxy using the I-band magnitude of the tip of the red giant branch, obtaining a value of 1030±50 kpc. This result combined with the velocity of DDO 210 shows that DDO 210 is a member of the Local Group.

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