A Keck/DEIMOS spectroscopic survey of the faint M31 satellites And IX, And XI, And XII, and And XIII

Details A Keck/DEIMOS spectroscopic survey of the faint M31 satellites And IX, And XI, And XII, and And XIII A Keck/DEIMOS spectroscopic survey of the faint M31 satellites And IX, And XI, And XII, and And XIII

2009-11-06

arxiv.org/abs/0911.1365v2

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

26 pages, 18 figures, MNRAS submitted

Scientific paper

We present the first spectroscopic analysis of the faint M31 satellite galaxies, AndXI and AndXIII, and a reanalysis of existing spectroscopic data for two further faint companions, And IX and AndXII. By combining data obtained using the DEIMOS spectrograph mounted on the Keck II telescope with deep photometry from the Suprime-Cam instrument on Subaru, we have calculated global properties for the dwarfs, such as systemic velocities, metallicites and half-light radii.We find each dwarf to be very metal poor ([Fe/H] -2 both photometrically and spectroscopically, from their stacked spectrum), and as such, they continue to follow the luminosity-metallicity relationship established with brighter dwarfs. We are unable to resolve a dispersion for And XI due to small sample size and low S/N, but we set a one sigma upper limit of sigma-v <5 km/s. For And IX, And XII and And XIII we resolve velocity dispersions of v=4.5 (+3.4,-3.2), 2.6(+5.1,-2.6) and 9.7(+8.9,-4.5) km/s, and derive masses within the half light radii of 6.2(+5.3,-5.1)x10^6 Msun, 2.4 (+6.5,-2.4)x10^6 Msun and 1.1(+1.4,-0.7)x10^7 Msun respectively. We discuss each satellite in the context of the Mateo relations for dwarf spheroidal galaxies, and the Universal halo profiles established for Milky Way dwarfs (Walker et al. 2009). For both galaxies, this sees them fall below the Universal halo profiles of Walker et al. (2009). When combined with the findings of McConnachie & Irwin (2006a), which reveal that the M31 satellites are twice as extended (in terms of both half-light and tidal radii) as their Milky Way counterparts, these results suggest that the satellite population of the Andromeda system could inhabit halos that are significantly different from those of the Milky Way in terms of their central densities (abridged).

Affiliated with

Also associated with

No associations

Rating

A Keck/DEIMOS spectroscopic survey of the faint M31 satellites And IX, And XI, And XII, and And XIII does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A Keck/DEIMOS spectroscopic survey of the faint M31 satellites And IX, And XI, And XII, and And XIII, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Keck/DEIMOS spectroscopic survey of the faint M31 satellites And IX, And XI, And XII, and And XIII will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-699311