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

@article{citeulike:6092491, abstract = {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 dispersions for And XI and And XIII due to small sample size and low S/N, but we set one sigma upper limits for each at sigma-v \<5 and 16 km/s respectively. For And IX and AndXII we resolve velocity dispersions of v=3.0 (+2.8,-3.0) and 2.2(+4.3,-2.2) km/s, and derive masses within the half light radii for both galaxies of 2.9(+3.8,-2.9)x10^6 Msun and 8.1 (+22,-8.1)x10^5 Msun respectively. We discuss each satellite in the context of the Mateo relations for dwarf spheroidal galaxies, and the Universal halo profiles established for MilkyWay 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).}, archivePrefix = {arXiv}, author = {Collins, M. L. M. and Chapman, S. C. and Irwin, M. J. and Martin, N. F. and Ibata, R. A. and Zucker, D. B. and Blain, A. and Ferguson, A. M. N. and Lewis, G. F. and McConnachie, A. W. and Penarrubia, J.}, citeulike-article-id = {6092491}, citeulike-linkout-0 = {http://arxiv.org/abs/0911.1365}, citeulike-linkout-1 = {http://arxiv.org/pdf/0911.1365}, day = {6}, eprint = {0911.1365}, keywords = {andies, astro-ph, deimos, keck, spectroscopy, velocity}, month = {Nov}, posted-at = {2009-11-10 09:38:23}, priority = {2}, title = {A Keck/DEIMOS spectroscopic survey of the faint M31 satellites And IX, And XI, And XII, and And XIII}, url = {http://arxiv.org/abs/0911.1365}, year = {2009} }

TY - JOUR ID - citeulike:6092491 L3 - citeulike-article-id:6092491 N2 - 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 dispersions for And XI and And XIII due to small sample size and low S/N, but we set one sigma upper limits for each at sigma-v <5 and 16 km/s respectively. For And IX and AndXII we resolve velocity dispersions of v=3.0 (+2.8,-3.0) and 2.2(+4.3,-2.2) km/s, and derive masses within the half light radii for both galaxies of 2.9(+3.8,-2.9)x10^6 Msun and 8.1 (+22,-8.1)x10^5 Msun respectively. We discuss each satellite in the context of the Mateo relations for dwarf spheroidal galaxies, and the Universal halo profiles established for MilkyWay 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). TI - A Keck/DEIMOS spectroscopic survey of the faint M31 satellites And IX, And XI, And XII, and And XIII KW - andies KW - astro-ph KW - deimos KW - keck KW - spectroscopy KW - velocity AU - Collins, MLM AU - Chapman, SC AU - Irwin, MJ AU - Martin, NF AU - Ibata, RA AU - Zucker, DB AU - Blain, A AU - Ferguson, AMN AU - Lewis, GF AU - McConnachie, AW AU - Penarrubia, J PY - 2009/Nov/06/ UR - http://arxiv.org/abs/0911.1365 ER -