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 Dark-Matter Content of Early-Type Galaxies with Planetary Nebulae

2007 ◽  
Vol 3 (S244) ◽  
pp. 289-294 ◽  
Author(s):  
N. R. Napolitano ◽  
A. J. Romanowsky ◽  
L. Coccato ◽  
M. Capaccioli ◽  
N. G. Douglas ◽  
...  
Keyword(s):  
Dark Matter ◽  
Planetary Nebula ◽  
Planetary Nebulae ◽  
Matter Content ◽  
The Other ◽  
Early Type ◽  
Scientific Objective ◽  
Target Sample ◽  
The Galaxy ◽  
William Herschel

AbstractWe examine the dark matter properties of nearby early-type galaxies using planetary nebulae (PNe) as mass probes. We have designed a specialised instrument, the Planetary Nebula Spectrograph (PN.S) operating at the William Herschel telescope, with the purpose of measuring PN velocities with best efficiency. The primary scientific objective of this custom-built instrument is the study of the PN kinematics in 12 ordinary round galaxies. Preliminary results showing a dearth of dark matter in ordinary galaxies (Romanowskyet al. 2003) are now confirmed by the first complete PN.S datasets. On the other hand early-type galaxies with a “regular” dark matter content are starting to be observed among the brighter PN.S target sample, thus confirming a correlation between the global dark-to-luminous mass virial ratio (fDM=MDMM*) and the galaxy luminosity and mass.

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 Kinematics and Angular Momentum in Early Type Galaxy Halos

2015 ◽  
Vol 11 (S317) ◽  
pp. 190-196 ◽  
Author(s):  
Jean P. Brodie ◽  
Aaron Romanowsky ◽  
Keyword(s):  
Angular Momentum ◽  
Globular Clusters ◽  
Planetary Nebulae ◽  
Wide Field ◽  
Early Type ◽  
Galaxy Halos ◽  
Galaxy Assembly ◽  
Early Type Galaxy

AbstractWe use the kinematics of discrete tracers, primarily globular clusters (GCs) and planetary nebulae (PNe), along with measurements of the integrated starlight to explore the assembly histories of early type galaxies. Data for GCs and stars are taken from the SLUGGS wide field, 2-dimensional, chemo-dynamical survey (Brodie et al. 2014). Data for PNe are from the PN.S survey (see contributions by Gerhard and by Arnaboldi, this volume). We find widespread evidence for 2-phase galaxy assembly and intriguing constraints on hierarchical merging under a lambda CDM cosmology.

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 Is there a dichotomy in the Dark Matter as well as in the Baryonic Matter properties of ellipticals?

2004 ◽  
Vol 220 ◽  
pp. 173-174
Author(s):  
N. R. Napolitano ◽  
M. Capaccioli ◽  
M. Arnaboldi ◽  
M. R. Merrifield ◽  
N. G. Douglas ◽  
...  
Keyword(s):  
Dark Matter ◽  
Structural Parameters ◽  
Matter Content ◽  
Baryonic Matter ◽  
Early Type

We have found a correlation between the M / L global gradients and the structural parameters of the luminous components of a sample of 19 early-type galaxies. Such a correlation supports the hypothesis that there is a connection between the dark matter content and the evolution of the baryonic component in such systems.

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