J/A+A/705/A112 Distances of Centaurus A and M83 galaxies (Faucher+, 2026)
Hubble-constant and -mass determination of Centaurus A and M83 from
tip-of-red-giant-branch distances.
Faucher A., Benisty D., Mota F.D.
<Astron. Astrophys. 705, A112 (2026)>
=2026A&A...705A.112F 2026A&A...705A.112F (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Stars, distances
Keywords: galaxies: groups: general - cosmological parameters
Abstract:
An independent determination of the Hubble constant is crucial in
light of the persistent tension between early- and late-Universe
measurements. In this study, we analyze the dynamics of the Centaurus
A (CenA) and M83 galaxies, along with their associated dwarf
companions identified via Tip of the Red Giant Branch (TRGB) distance
measurements, to constrain both the group mass and the local value of
H0. By examining the motions of these galaxies relative to the
system's barycenter, we apply both the minor and major infall
models, which provide bounds on the true radial velocity dispersion.
From the overlap from these approaches, we obtain a virial mass
estimate of (7.3±2.0)x1012M☉ and a Hubble flow-based mass of
(2.6±1.4)x1012M☉. Modeling the cold Hubble flow around the
group center-of-mass, we derive a corresponding value of the Hubble
constant as (64.0±4.6)km/s/Mpc. These results offer an independent,
dynamically motivated constraint on the local value of H0, explicitly
accounting for the impact of peculiar velocities in the nearby
Universe. We also discuss the ∼2σ tension between the virial and
Hubble flow-based mass estimates, which likely arises from the fact
that M83 is close to the velocity surface and break the Hubble flow
model assumptions. While the Hubble flow fit emphasizes galaxies that
follow smooth expansion on the lower branch of the velocity-distance
relation, the virial mass estimate is found to be in good agreement
with the group mass derived from the K-band luminosity of its
brightest members and the projected mass methods.
Description:
Catalog of galaxies in the Centaurus A and M83 groups and nearby
galaxies. Includes coordinates (J2000), distances with uncertainties,
velocities from the Local Group with uncertainties. Galaxies are
flagged for their usage in Hubble flow fitting (major and minor axes)
and virial mass calculations. Data compiled from the Extragalactic
Distance Database (EDD) and recent studies of dwarf galaxies in these
groups by Muller et al. (2025A&A...699A.207M 2025A&A...699A.207M).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 64 157 Catalog of galaxies in the Centaurus A and M83
groups and nearby galaxies
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- Name Galaxy identifier
25- 32 F8.4 deg RAdeg Right Ascension (J2000)
34- 41 F8.4 deg DEdeg Declination (J2000)
43- 47 F5.2 Mpc Dist Distance (central value)
49- 54 F6.1 km/s vLG Velocity relative to Local Group
(central value)
56 A1 --- Hubble-Min Flag (Y) if used in minor axis Hubble fit
58 A1 --- Hubble-Maj Flag (Y) if used in major axis Hubble fit
60 A1 --- Virial-Min Flag (Y) if used in minor axis virial mass
62 A1 --- Virial-Maj Flag (Y) if used in major axis virial mass
64 I1 --- Ref [1/2] Data source (1)
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Note (1): References as follows:
1 = EDD, Extragalactic Distance Database (Tully et al., 2009AJ....138..323T 2009AJ....138..323T)
2 = studies of dwarf galaxies in the Cen A and M83 groups
(Muller et al., 2021A&A...645A..92M 2021A&A...645A..92M, 2025A&A...699A.207M 2025A&A...699A.207M)
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Acknowledgements:
David Benisty, benidav(at)aip.de
(End) Patricia Vannier [CDS] 02-Dec-2025