English

The faint end of the Centaurus A satellite luminosity function

Astrophysics of Galaxies 2019-02-20 v2

Abstract

The Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS) is constructing a wide-field map of the resolved stellar populations in the extended halos of these two nearby, prominent galaxies. We present new Magellan/Megacam imaging of a 3\sim3 deg2^2 area around Centaurus A (Cen A), which filled in much of our coverage to its south, leaving a nearly complete halo map out to a projected radius of \sim150 kpc and allowing us to identify two new resolved dwarf galaxies. We have additionally obtained deep Hubble Space Telescope (HST) optical imaging of eleven out of the thirteen candidate dwarf galaxies identified around Cen A and presented in Crnojevi\'c et al. (2016): seven are confirmed to be satellites of Cen A, while four are found to be background galaxies. We derive accurate distances, structural parameters, luminosities and photometric metallicities for the seven candidates confirmed by our HST/ACS imaging. We further study the stellar population along the \sim60 kpc long (in projection) stream associated with Dw3, which likely had an initial brightness of MVM_{V}\sim-15 and shows evidence for a metallicity gradient along its length. Using the total sample of eleven dwarf satellites discovered by the PISCeS survey, as well as thirteen brighter previously known satellites of Cen A, we present a revised galaxy luminosity function for the Cen A group down to a limiting magnitude of MV8M_V\sim-8, which has a slope of 1.14±0.17-1.14\pm0.17, comparable to that seen in the Local Group and in other nearby groups of galaxies.

Keywords

Cite

@article{arxiv.1809.05103,
  title  = {The faint end of the Centaurus A satellite luminosity function},
  author = {D. Crnojević and D. J. Sand and P. N. Bennet and S. Pasetto and K. Spekkens and N. Caldwell and P. Guhathakurta and B. McLeod and A. Seth and J. D. Simon and J. Strader and E. Toloba},
  journal= {arXiv preprint arXiv:1809.05103},
  year   = {2019}
}

Comments

26 pages, 15 figures; ApJ in press

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