A common mass scale for satellite galaxies of the Milky Way

Strigari, Louis E.; Bullock, James S.; Kaplinghat, Manoj; Simon, Joshua D.; Geha, Marla; Willman, Beth; Walker, Matthew G.

doi:10.1038/nature07222

Cited by 516 publications

(782 citation statements)

References 47 publications

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“…Various arguments based on the kinematics of the nine bright 'classical' dwarf spheroidal satellites of the MW suggest that they reside in subhaloes with maximum circular velocities of V max 30 km s −1 (Peñarrubia, McConnachie & Navarro 2008;Strigari et al 2008;Łokas 2009;Walker et al 2009;Strigari et al 2010;Wolf et al 2010), or even V max 25 km s −1 (Boylan-Kolchin et al 2012). If this is indeed the case, only the two Magellanic Clouds (MCs) and the Sagittarius dwarf would reside in dark matter substructures with larger maximum velocity than this.…”

Section: Introductionmentioning

confidence: 99%

Milky Way mass constraints from the Galactic satellite gap

Cautun

Frenk

Weygaert

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We use the distribution of maximum circular velocities, V max , of satellites in the Milky Way (MW) to constrain the virial mass, M 200 , of the Galactic halo under an assumed prior of a ΛCDM universe. This is done by analysing the subhalo populations of a large sample of halos found in the Millennium II cosmological simulation. The observation that the MW has at most three subhalos with V max 30 km/s requires a halo mass M 200 1.4 × 10 12 M , while the existence of the Magellanic Clouds (assumed to have V max 60 km/s) requires M 200 1.0 × 10 12 M . The first of these conditions is necessary to avoid the "too-big-to-fail" problem highlighted by Boylan-Kolchin et al., while the second stems from the observation that massive satellites like the Magellanic Clouds are rare. When combining both requirements, we find that the MW halo mass must lie in the range 0.25 M 200 /(10 12 M ) 1.4 at 90% confidence. The gap in the abundance of Galactic satellites between 30 km/s V max 60 km/s places our galaxy in the tail of the expected satellite distribution.

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Section: Introductionmentioning

confidence: 99%

Milky Way mass constraints from the Galactic satellite gap

Cautun

Frenk

Weygaert

et al. 2014

Monthly Notices of the Royal Astronomical Society

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“…These include for example, the existence of a possible common mass scale of dwarf spheroidals (e.g. Strigari et al 2008), and the tight constraints on the total mass within the half-light radius of these systems (Walker et al 2010;Wolf et al 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Kleyna et al 2001;Battaglia et al 2008;Strigari et al 2008;Lokas 2009;), while for more distant objects, such as the dSph satellites of M31, masses have been derived from the average velocity dispersion and projected mass estimators (Kalirai et al 2010;Collins et al 2010). In Jeans models one has to specify (i) the form of the light distribution, (ii) the density profile (or equivalently the gravitational potential) of the dark matter component, and (iii) velocity anisotropy of the stars.…”

Section: Introductionmentioning

confidence: 99%

Orbit-based dynamical models of the Sculptor dSph galaxy

Breddels¹,

Helmi²,

Bosch³

et al. 2013

Monthly Notices of the Royal Astronomical Society

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We have developed spherically symmetric dynamical models of dwarf spheroidal galaxies using Schwarzschild's orbit superposition method. This type of modelling yields constraints both on the total mass distribution (e.g. enclosed mass and scale radius) as well as on the orbital structure of the system (e.g. velocity anisotropy). This method is thus less prone to biases introduced by assumptions in comparison to the more commonly used Jeans modelling, and it allows us to derive the dark matter content in a robust way. Here we present our results for the Sculptor dwarf spheroidal galaxy, after testing our methods on mock data sets. We fit both the second and fourth velocity moment profile to break the mass-anisotropy degeneracy. For an NFW dark matter halo profile, we find that the mass of Sculptor within 1 kpc is M 1kpc = (1.03 ± 0.07) × 10 8 M ⊙ , and that its velocity anisotropy profile is tangentially biased and nearly constant with radius. The preferred concentration (c ∼ 15) is low for its dark matter mass but consistent within the scatter found in N-body cosmological simulations. When we let the value of the central logarithmic slope α vary, we find that the best-fit model has α = 0, although an NFW cusp or shallower is consistent at 1σ confidence level. On the other hand, very cuspy density profiles with logarithmic central slopes α < −1.5 are strongly disfavoured for Sculptor.

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“…Continued active mining of these data bases continues to unveil not only new tidal debris streams (e.g., Rocha-Pinto et al 2004, Sharma et al 2009for 2MASS, and Belokurov et al 2007b, Grillmair 2009, Newberg et al 2009 for SDSS, to name just some examples), but of course a plethora of new dSph galaxies of extremely low luminosity (e.g., Willman et al 2005, Zucker et al 2006, Belokurov et al 2007a, Grillmair 2009). These ultrafaint dSphs tend to have very high M/L ratios (Muñoz et al 2006b, Simon & Geha 2007) that point to a common dSph mass scale (Strigari et al 2008), which may arise from some critical scale in the formation of galaxies or a characteristic scale for the clustering of DM. But a few ultrafaints show evidence for tidal disruption and dynamical instability (e.g., Coleman et al 2007) and may represent exceptions to the common mass scale (Adén et al 2009).…”

Section: Wide Field Photometric Surveys In the Coming Decadementioning

confidence: 99%

The Future of Stellar Populations Studies in the Milky Way and the Local Group

Majewski

2009

Proc. IAU

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Abstract. The last decade has seen enormous progress in understanding the structure of the Milky Way and neighboring galaxies via the production of large-scale digital surveys of the sky like 2MASS and SDSS, as well as specialized, counterpart imaging surveys of other Local Group systems. Apart from providing snaphots of galaxy structure, these "cartographic" surveys lend insights into the formation and evolution of galaxies when supplemented with additional data (e.g., spectroscopy, astrometry) and when referenced to theoretical models and simulations of galaxy evolution. These increasingly sophisticated simulations are making ever more specific predictions about the detailed chemistry and dynamics of stellar populations in galaxies. To fully exploit, test and constrain these theoretical ventures demands similar commitments of observational effort as has been plied into the previous imaging surveys to fill out other dimensions of parameter space with statistically significant intensity. Fortunately the future of large-scale stellar population studies is bright with a number of grand projects on the horizon that collectively will contribute a breathtaking volume of information on individual stars in Local Group galaxies. These projects include: (1) additional imaging surveys, such as Pan-STARRS, SkyMapper and LSST, which, apart from providing deep, multicolor imaging, yield time series data useful for revealing variable stars (including critical standard candles, like RR Lyrae variables) and creating large-scale, deep proper motion catalogs; (2) higher accuracy, space-based astrometric missions, such as Gaia and SIM-Lite, which stand to provide critical, high precision dynamical data on stars in the Milky Way and its satellites; and (3) large-scale spectroscopic surveys provided by RAVE, APOGEE, HERMES, LAMOST, and the Gaia spectrometer, which will yield not only enormous numbers of stellar radial velocities, but extremely comprehensive views of the chemistry of stellar populations. Meanwhile, previously dust-obscured regions of the Milky Way will continue to be systematically exposed via large infrared surveys underway or on the way, such as the various GLIMPSE surveys from Spitzer's IRAC instrument, UKIDSS, APOGEE, JASMINE and WISE.

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A common mass scale for satellite galaxies of the Milky Way

Cited by 516 publications

References 47 publications

Milky Way mass constraints from the Galactic satellite gap

Milky Way mass constraints from the Galactic satellite gap

Orbit-based dynamical models of the Sculptor dSph galaxy

The Future of Stellar Populations Studies in the Milky Way and the Local Group

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