The detection of ultra-faint low surface brightness dwarf galaxies in the Virgo Cluster: a Probe of Dark Matter and Baryonic Physics

Abstract

We have discovered 11 ultra-faint ($r\lesssim 22.1$) low surface brightness (LSB, central surface brightness $23\lesssim {\mu }_r\lesssim 26$) dwarf galaxy candidates in one deep Virgo field of just $576$ arcmin${}^2$ obtained by the Large Binocular Camera (LBC) at the Large Binocular Telescope (LBT). Their association with the Virgo cluster is supported by their distinct position in the central surface brightness - total magnitude plane with respect to the background galaxies of similar total magnitude. They have typical absolute magnitudes and scale sizes, if at the distance of Virgo, in the range $-13\lesssim M_r\lesssim -9$ and $250\lesssim r_s\lesssim 850$ pc, respectively. Their colors are consistent with a gradually declining star formation history with a specific star formation rate of the order of $10^{-11}$ yr${}^{-1}$, i.e. 10 times lower than that of main sequence star forming galaxies. They are older than the cluster formation age and appear regular in morphology. They represent the faintest extremes of the population of low luminosity LSB dwarfs that has been recently detected in wider surveys of the Virgo cluster. Thanks to the depth of our observations we are able to extend the Virgo luminosity function down to $M_r\sim -9.3$ (corresponding to total masses $M\sim 10^7$ M${}_{\odot }$), finding an average faint-end slope $\alpha \simeq -1.4$. This relatively steep slope puts interesting constraints on the nature of the Dark Matter and in particular on warm Dark Matter (WDM) often invoked to solve the overprediction of the dwarf number density by the standard CDM scenario. We derive a lower limit on the WDM particle mass $>1.5$ keV.

accepted for publication in ApJ, 13 pages, 6 figures

References in corpus (13)

• Physical Models of Galaxy Formation in a Cosmological Framework
• Forming Disk Galaxies in Lambda CDM Simulations
• The Galaxy Mass Function up to z=4 in the GOODS-MUSIC sample: into the epoch of formation of massive galaxies
• The GOODS-MUSIC sample: a multicolour catalog of near-IR selected galaxies in the GOODS-South field
• Is there a "too big to fail" problem in the field?
• Bent by baryons: the low mass galaxy-halo relation
• The performance of the blue prime focus Large Binocular Camera at the Large Binocular Telescope
• Spectroscopic Determination of the Faint End of the Luminosity Function in the Nearby Galaxy Clusters A2199 and Virgo
• Triggering Active Galactic Nuclei in Hierarchical Galaxy Formation: Disk instability vs. Interactions
• Expanded haloes, abundance matching and too-big-to-fail in the Local Group
• The Dynamics of Subhalos in Warm Dark Matter Models
• Nonlinear evolution of dark matter subhalos and applications to warm dark matter
• Deep R-band counts of z~3 Lyman break galaxy candidates with the LBT

Cited by in corpus (6)

• DGSAT: Dwarf Galaxy Survey with Amateur Telescopes I. Discovery of low surface brightness systems around nearby spiral galaxies
• Faint progenitors of luminous $z\sim 6$ quasars: why don't we see them?
• Globular Clusters, Ultracompact Dwarfs, and Dwarf Galaxies in Abell 2744 at the Redshift of 0.308
• A study of the HI and optical properties of Low Surface Brightness galaxies: spirals, dwarfs and irregulars
• Understanding the chemical evolution of blue Edge-on Low Surface Brightness Galaxies
• Observing the very low-surface brightness dwarfs in a deep field in the VIRGO cluster: constraints on Dark Matter scenarios