2016ApJ...823...19C -
Astrophys. J., 823, 19-19 (2016/May-3)
The extended halo of Centaurus A: uncovering satellites, streams, and substructures.
CRNOJEVIC D., SAND D.J., SPEKKENS K., CALDWELL N., GUHATHAKURTA P., McLEOD B., SETH A., SIMON J.D., STRADER J. and TOLOBA E.
Abstract (from CDS):
We present the widest-field resolved stellar map to date of the closest ( D∼3.8 Mpc) massive elliptical galaxy NGC 5128 (Centaurus A; Cen A), extending out to a projected galactocentric radius of ∼150 kpc. The data set is part of our ongoing Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS) utilizing the Magellan/Megacam imager. We resolve a population of old red giant branch (RGB) stars down to ∼1.5 mag below the tip of the RGB, reaching surface brightness limits as low as µ_{V,0}∼32 mag arcsec–2. The resulting spatial stellar density map highlights a plethora of previously unknown streams, shells, and satellites, including the first tidally disrupting dwarf around Cen A (CenA-MM-Dw3), which underline its active accretion history. We report 13 previously unknown dwarf satellite candidates, of which 9 are confirmed to be at the distance of Cen A (the remaining 4 are not resolved into stars), with magnitudes in the range {M}_{V}=-7.2 to -13.0, central surface brightness values of µ_{V,0}=25.4–26.9 mag arcsec–2, and half-light radii of {r}_{h}=0.22–2.92 kpc . These values are in line with Local Group dwarfs but also lie at the faint/diffuse end of their distribution; interestingly, CenA-MM-Dw3 has similar properties to the recently discovered ultradiffuse galaxies in Virgo and Coma. Most of the new dwarfs are fainter than the previously known Cen A satellites. The newly discovered dwarfs and halo substructures are discussed in light of their stellar populations, and they are compared to those discovered by the PAndAS survey of M31.
Abstract Copyright:
© 2016. The American Astronomical Society. All rights reserved.
Journal keyword(s):
galaxies: dwarf - galaxies: groups: individual: CenA - galaxies: halos - galaxies: photometry
Nomenclature:
Fig. 4, Tables 1+3: [CSC2014] CenA-MM-DwN (Nos Dw3-Dw13). Fig. 4, Paragr. 4.4: [CSS2016b] Cloud S N=1.
Simbad objects:
49
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