scholarly journals The total mass of the early-type galaxy NGC 4649 (M60)

2008 ◽  
pp. 1-7
Author(s):  
S. Samurovic ◽  
M.M. Cirkovic
Keyword(s):  
Dark Matter ◽  
Total Mass ◽  
Globular Clusters ◽  
X Rays ◽  
Early Type ◽  
X Ray ◽  
Modified Newtonian Dynamics ◽  
Newtonian Dynamics ◽  
Early Type Galaxy

In this paper the problem of the total mass and the total mass-to-light ratio of the early-type galaxy NGC 4649 (M60) is analyzed. Use is made of two independent techniques: the X-ray methodology which is based on the temperature of the X-ray halo of NGC 4649 and the tracer mass estimator (TME) which uses globular clusters (GCs) observed in this galaxy. The mass is calculated in Newtonian and Modified Newtonian Dynamics (MOND) approaches and it is found that inside 3 effective radii (Re ) there is no need for large amounts of dark matter. Beyond 3Re the dark matter starts to play important dynamical role. The possible reasons for the discrepancy between the estimates of the total mass based on X-rays and TME in the outer regions of NGC 4649 are also discussed.

scholarly journals Globular clusters and planetary nebulae kinematics and X-ray emission in the early-type galaxy NGC 5128

2006 ◽  
pp. 35-47 ◽  
Author(s):  
S. Samurovic
Keyword(s):  
Dark Matter ◽  
Total Mass ◽  
Globular Clusters ◽  
Planetary Nebulae ◽  
X Rays ◽  
X Ray ◽  
The Galaxy ◽  
The One ◽  
Early Type Galaxy ◽  
Good Agreement

The estimates of the mass of the galaxy NGC 5128 based on the different mass tracers, globular clusters (GCs) and planetary nebulae (PNe), are presented. These estimates are compared with the estimate based on the X-ray methodology and it is found that the results for the mass (and mass-to-light ratio) for all three approaches are in very good agreement interior to 25 arcmin; beyond 25 arcmin the X-rays predict the mass which is too high with respect to the one found using GCs and PNe. Some possible explanations for this discrepancy were discussed. The Jeans equation is also solved and its predictions for the velocity dispersion are then compared with the observed values, which extend to ~8 effective radii in the case of the GCs and ~15 effective radii in the case of the PNe. It is found that interior to ~25 arcmin (~5 effective radii) dark matter does not dominate because the total mass-to-light ratio in the B band in solar units is less than 10. Based on the GCs and PNe beyond ~25 arcmin the total mass-to-light ratio increases to ~14 (at ~80 arcmin) which indicates the existence of dark matter in the outer regions of NGC 5128.

scholarly journals Low dark matter content of the nearby early-type galaxy NGC 821

2014 ◽  
pp. 29-36 ◽  
Author(s):  
S. Samurovic ◽  
A. Vudragovic ◽  
M. Jovanovic ◽  
M.M. Cirkovic
Keyword(s):  
Dark Matter ◽  
Globular Clusters ◽  
Planetary Nebulae ◽  
Matter Content ◽  
Kinematics And Dynamics ◽  
Constant Mass ◽  
Early Type ◽  
Kinematic Data ◽  
Early Type Galaxy ◽  
Dynamical Modelling

In this paper we analyze the kinematics and dynamics of the nearby early-type galaxy NGC 821 based on its globular clusters (GCs) and planetary nebulae (PNe). We use PNe and GCs to extract the kinematics of NGC 821 which is then used for the dynamical modelling based on the Jeans equation. We apply the Jeans equation using the Newtonian mass-follows-light approach assuming constant mass-to-light ratio and find that using such an approach we can successfully fit the kinematic data. The inferred constant mass-to-light ratio, 4:2 < M=LB < 12:4 present throughout the whole galaxy, implies the lack of significant amount of dark matter. We also used three different MOND approaches and found that we can fit the kinematic data without the need for additional, dark, component.

scholarly journals Distance and mass of the M 104 (Sombrero) group

2020 ◽  
Vol 643 ◽  
pp. A124
Author(s):  
Igor D. Karachentsev ◽  
Lidia N. Makarova ◽  
R. Brent Tully ◽  
Gagandeep S. Anand ◽  
Luca Rizzi ◽  
...  
Keyword(s):  
Dark Matter ◽  
Total Mass ◽  
Dwarf Galaxies ◽  
Radial Velocities ◽  
Early Type ◽  
Space Telescope ◽  
Dark Matter Mass ◽  
Red Giant ◽  
Advanced Camera For Surveys ◽  
Early Type Galaxy

Aims. Distances and radial velocities of galaxies in the vicinity of the luminous early-type galaxy M 104 (Sombrero) are used to derive its dark matter mass. Methods. Two dwarf galaxies: UGCA 307 and KKSG 30 situated near M 104 were observed with the Advanced Camera for Surveys on the Hubble Space Telescope. The distances 9.03−0.51+0.84 Mpc (UGCA 307) and 9.72−0.41+0.44 Mpc (KKSG 30) were determined using the tip of the red giant branch method. These distances are consistent with the dwarf galaxies being satellites of Sombrero. Results. Using radial velocities and projected separations of UGCA 307, KKSG 30, and a third galaxy with an accurate distance (KKSG 29), as well as 12 other assumed companions with less accurate distances, the total mass of M 104 is estimated to be (1.55 ± 0.49) × 1013 M⊙. At the K-band luminosity of the Sombrero galaxy of 2.4 × 1011 L⊙, its total mass-to-luminosity ratio is MT/LK = (65 ± 20) M⊙/L⊙, which is about three times higher than that of luminous bulgeless galaxies.

scholarly journals X-rays and dynamics

2009 ◽  
Vol 5 (H15) ◽  
pp. 91-91
Author(s):  
Silvia Pellegrini
Keyword(s):  
Interstellar Medium ◽  
Total Mass ◽  
Hydrostatic Equilibrium ◽  
X Rays ◽  
Early Type ◽  
X Ray

AbstractThe hot X-ray emitting interstellar medium of early type galaxies can be used in principle as a total mass tracer and a tool to determine the stellar orbital anisotropy, based on the hypothesis of hydrostatic equilibrium for it. Here the effects that deviations from equilibrium have on both estimates are shown, and a comparison is made with cases for which accurate optical and X-ray information are available.

scholarly journals Survey of Gravitationally Lensed Objects in HSC Imaging (SuGOHI) – VII. Discovery and confirmation of three strongly lensed quasars†

2021 ◽  
Vol 502 (1) ◽  
pp. 1487-1493
Author(s):  
Anton T Jaelani ◽  
Cristian E Rusu ◽  
Issha Kayo ◽  
Anupreeta More ◽  
Alessandro Sonnenfeld ◽  
...  
Keyword(s):  
Spectroscopic Data ◽  
Point Sources ◽  
Sloan Digital Sky Survey ◽  
Early Type ◽  
Blue Point ◽  
X Ray ◽  
Quasar Spectra ◽  
Strategic Program ◽  
Early Type Galaxy

ABSTRACT We present spectroscopic confirmation of three new two-image gravitationally lensed quasars, compiled from existing strong lens and X-ray catalogues. Images of HSC J091843.27–022007.5 show a red galaxy with two blue point sources at either side, separated by 2.26 arcsec. This system has a source and a lens redshifts zs = 0.804 and zℓ = 0.459, respectively, as obtained by our follow-up spectroscopic data. CXCO J100201.50+020330.0 shows two point sources separated by 0.85 arcsec on either side of an early-type galaxy. The follow-up spectroscopic data confirm the fainter quasar has the same redshift with the brighter quasar from the Sloan Digital Sky Survey (SDSS) fiber spectrum at zs = 2.016. The deflecting foreground galaxy is a typical early-type galaxy at a redshift of zℓ = 0.439. SDSS J135944.21+012809.8 has two point sources with quasar spectra at the same redshift zs = 1.096, separated by 1.05 arcsec, and fits to the HSC images confirm the presence of a galaxy between these. These discoveries demonstrate the power of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP)’s deep imaging and wide sky coverage. Combined with existing X-ray source catalogues and follow-up spectroscopy, the HSC-SSP provides us unique opportunities to find multiple-image quasars lensed by a foreground galaxy.

scholarly journals Chemical Abundances of Early Type Stars

1998 ◽  
Vol 188 ◽  
pp. 224-225
Author(s):  
S. Tanaka ◽  
S. Kitamoto ◽  
T. Suzuki ◽  
K. Torii ◽  
M.F. Corcoran ◽  
...  
Keyword(s):  
Surface Layer ◽  
Stellar Wind ◽  
Nuclear Reactions ◽  
X Rays ◽  
Early Type ◽  
Chemical Abundances ◽  
X Ray ◽  
Low Metallicity ◽  
Early Type Stars

X-rays from early-type stars are emitted by the corona or the stellar wind. The materials in the surface layer of early-type stars are not contaminated by nuclear reactions in the stellar inside. Therefore, abundance study of the early-type stars provides us an information of the abundances of the original gas. However, the X-ray observations indicate low-metallicity, which is about 0.3 times of cosmic abundances. This fact raises the problem on the cosmic abundances.

scholarly journals Ultradiffuse galaxies in the IC 1459 group from the VEGAS survey

2020 ◽  
Vol 494 (4) ◽  
pp. 5293-5297
Author(s):  
Duncan A Forbes ◽  
Bililign T Dullo ◽  
Jonah Gannon ◽  
Warrick J Couch ◽  
Enrichetta Iodice ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Compact Objects ◽  
Early Type ◽  
Group Members ◽  
Measurement Uncertainties ◽  
Stellar Masses ◽  
Double Nucleus ◽  
Early Type Galaxy

ABSTRACT Using deep g, r, i imaging from the VST Early-type GAlaxy Survey (VEGAS), we have searched for ultradiffuse galaxies (UDGs) in the IC 1459 group. Assuming they are group members, we identify nine galaxies with physical sizes and surface brightnesses that match the UDG criteria within our measurement uncertainties. They have mean colours of g − i = 0.6 and stellar masses of ∼108 M⊙. Several galaxies appear to have associated systems of compact objects, e.g. globular clusters. Two UDGs contain a central bright nucleus, with a third UDG revealing a remarkable double nucleus. This appears to be the first reported detection of a double nucleus in a UDG – its origin is currently unclear.

scholarly journals The relation between the gas, dust and total mass in edge-on spiral galaxies

2014 ◽  
Vol 10 (S309) ◽  
pp. 297-297
Author(s):  
Flor Allaert
Keyword(s):  
Dark Matter ◽  
Total Mass ◽  
Spiral Galaxies ◽  
3D Structure ◽  
Early Type ◽  
Interstellar Gas ◽  
Data Set ◽  
Unique Role ◽  
Radio Data ◽  
Multi Wavelength

AbstractEach component of a galaxy plays its own unique role in regulating the galaxy's evolution. In order to understand how galaxies form and evolve, it is therefore crucial to study the distribution and properties of each of the various components, and the links between them, both radially and vertically. The latter is only possible in edge-on systems. We present the HEROES project, which aims to investigate the 3D structure of the interstellar gas, dust, stars and dark matter in a sample of 7 massive early-type spiral galaxies based on a multi-wavelength data set including optical, NIR, FIR and radio data.

scholarly journals 2dF Spectroscopy of Globular Clusters in M104

2005 ◽  
Vol 13 ◽  
pp. 199-199
Author(s):  
Terry Bridges ◽  
Steve Zepf ◽  
Katherine Rhode ◽  
Ken Freeman
Keyword(s):  
Dark Matter ◽  
Strong Evidence ◽  
Total Mass ◽  
Globular Clusters ◽  
Total Sample ◽  
Dark Matter Halo ◽  
Large Radius ◽  
Counter Rotation ◽  
Spatial Coverage

AbstractWe have found 56 new globular clusters in M104 from 2dF multi-fiber spectroscopy, doubling the number of confirmed clusters, and extending the spatial coverage to 50 kpc radius. We find no significant rotation in the total sample, or for subsets split by color or radius. However, there are hints that the blue clusters have a higher rotation than the red clusters, and for counter-rotation of clusters at large radius. We find a total mass of M ~ 1 × 1012M⊙ and a (M/L)B =30 out to 50 kpc radius, which is strong evidence for a dark matter halo in M104.

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