The pride of lions around Messier 105

I. D. Karachentsev; E. I. Kaisina; V. E. Karachentseva

doi:10.1093/mnras/stad593

paper

The pride of lions around Messier 105

arXiv:2302.10948 · doi:10.1093/mnras/stad593

Abstract

We undertook a search for new dwarf galaxies in the Leo-I group using the data from the DECaLS digital sky survey. Five new presumed members of this group have been found in a wide vicinity of $M 105 (NGC 3379$ ). Currently, the group has a population of $83$ galaxies, $33$ of which have measured radial velocities. More than half of the group members belong to early types with no signs of ongoing star formation. About a quarter of the galaxies are outside the group's virial radius, $R_{v} = 385$ ~kpc. The presence of multiple systems with a size of about 15~kpc is evident in the group, but there are no noticeable global flat or filamentary substructures. The luminosity function of the group looks to be deficient in galaxies with absolute magnitudes in the interval $M_{B} = [- 18, - 15]$ mag. The $M 105$ group is characterized by a radial velocity dispersion of $136$ ~km~s $^{- 1}$ , orbital mass estimate $(5.76 \pm 1.32) \times 1 0^{12} M_{⊙}$ , and the total mass-to-K-band-luminosity ratio $(17.8 \pm 4.1) M_{⊙} / L_{⊙}$ . The neighboring group of galaxies around $M 66 (NGC 3627$ ) has a similar virial radius, $390$ ~kpc, velocity dispersion, $135$ ~km~s $^{- 1}$ , and total mass-to-luminosity ratio, $(15.6 \pm 3.9) M_{⊙} / L_{⊙}$ . Both groups in the Leo constellation are approaching the Local Group with a velocity of about 100~km~s $^{- 1}$ . In the background of the $M 105$ group, we noted a group of 6 galaxies with an unusually low virial mass-to-luminosity ratio, $M_{T} / L_{K} = (4.1 \pm 2.2) M_{⊙} / L_{⊙}$ .

arXiv comment12 pages, 5 figures, 4 tables, accepted for MNRAS

The pride of lions around Messier 105

Abstract

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