English

The pride of lions around Messier 105

Astrophysics of Galaxies 2023-03-08 v1

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 M105(NGC3379{\rm M}\,105 ({\rm NGC}\,3379). Currently, the group has a population of 8383 galaxies, 3333 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, Rv=385R_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 MB=[18,15]M_B = [-18, -15] mag. The M105{\rm M}\,105 group is characterized by a radial velocity dispersion of 136136~km~s1^{-1}, orbital mass estimate (5.76±1.32)×1012 M(5.76\pm1.32)\times 10^{12}~M_{\odot}, and the total mass-to-K-band-luminosity ratio (17.8±4.1)M/L(17.8\pm4.1) M_\odot/L_\odot. The neighboring group of galaxies around M66(NGC3627{\rm M}\,66 ({\rm NGC}\,3627) has a similar virial radius, 390390~kpc, velocity dispersion, 135135~km~s1^{-1}, and total mass-to-luminosity ratio, (15.6±3.9)M/L(15.6\pm3.9) M_\odot/L_\odot. Both groups in the Leo constellation are approaching the Local Group with a velocity of about 100~km~s1^{-1}. In the background of the M105{\rm M}\,105 group, we noted a group of 6 galaxies with an unusually low virial mass-to-luminosity ratio, MT/LK=(4.1±2.2)M/LM_T/L_K = (4.1\pm2.2) M_\odot/L_\odot.

Keywords

Cite

@article{arxiv.2302.10948,
  title  = {The pride of lions around Messier 105},
  author = {I. D. Karachentsev and E. I. Kaisina and V. E. Karachentseva},
  journal= {arXiv preprint arXiv:2302.10948},
  year   = {2023}
}

Comments

12 pages, 5 figures, 4 tables, accepted for MNRAS