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Dwarfs in the entourage of the Local Volume groups: flow tracers and cosmological probes

Published online by Cambridge University Press:  30 October 2019

Olga Kashibadze Open the ORCID record for Olga Kashibadze [Opens in a new window] ,
Igor Karachentsev  and
Valentina Karachentseva
Olga Kashibadze
Affiliation:
Special Astrophysical Observatory of RAS, Nizhnij Arkhyz, Russia
Igor Karachentsev
Affiliation:
Special Astrophysical Observatory of RAS, Nizhnij Arkhyz, Russia
Valentina Karachentseva
Affiliation:
Main Astronomical Observatory of NASU, Kyiv, Ukraine
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Abstract

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We consider a sample of dwarf galaxies with accurate distances and velocities around 14 massive groups in the Local Volume. We combine all the data into a single synthetic group, and then determine its radius of the zero-velocity surface, separating it against the global cosmic expansion. Our estimation is derived from fitting the the spherical infall model (including effects of the cosmological constant) to the observational data.

We found the optimal value of the radius to be 0.93 ± 0.02 Mpc. Assuming the Planck model parameters, it corresponds to the total mass of the synthetic group (1.6 ± 0.2) × 1012M⊙. Thus, we obtain the paradoxical result that the total mass of the synthetic group estimated on the scale of 3–4 its virial radius is only 60% of the virial mass estimate. Anyway, we conclude that wide outskirts of the nearby groups do not contain a large amount of hidden mass outside their virial radii.

Keywords

galaxies: distances and redshiftscosmology: observations(cosmology:) large-scale structure of universe(cosmology:) cosmological parameters
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 14 , Symposium S344: Dwarf Galaxies: From the Deep Universe to the Present , August 2018 , pp. 488 - 490
Copyright
© International Astronomical Union 2019 

References

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