Proper Motions of Dwarf Spheroidal Galaxies from<i>Hubble Space Telescope</i>Imaging. IV. Measurement for Sculptor

Piatek, Slawomir; Pryor, C.; Bristow, Paul; Olszewski, Edward W.; Harris, Hugh C.; Mateo, Mario; Minniti, D.; Tinney, C. G.

doi:10.1086/499526

Cited by 90 publications

(137 citation statements)

References 46 publications

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“…In the case of Sculptor, a similar orbital study was carried out by Piatek et al (2006). They obtain 95% confidence intervals on perigalacticon and apogalacticon of 31 < rp < 83 kpc and 97 < ra < 313 kpc, implying 0.26 < e < 0.60 with the Galactic potential model from Johnston et al (1995).…”

Section: Orbital Motionsmentioning

confidence: 81%

Tidal features of classical Milky Way satellites in a Λ cold dark matter universe

Wang

Fattahi

Cooper

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We use the APOSTLE cosmological hydrodynamic simulations to examine the effects of tidal stripping on cold dark matter (CDM) subhaloes that host three of the most luminous Milky Way (MW) dwarf satellite galaxies: Fornax, Sculptor, and Leo I. We identify simulated satellites that match the observed spatial and kinematic distributions of stars in these galaxies, and track their evolution after infall. We find ∼ 30% of subhaloes hosting satellites with present-day stellar mass 10 6 -10 8 M ⊙ experience > 20% stellar mass loss after infall. Fornax analogues have earlier infall times compared to Sculptor and Leo I analogues. Star formation in Fornax analogues continues for ∼ 3-6 Gyr after infall, whereas Sculptor and Leo I analogues stop forming stars < 2-3 Gyr after infall. Fornax analogues typically show more significant stellar mass loss and exhibit stellar tidal tails, whereas Sculptor and Leo I analogues, which are more deeply embedded in their host DM haloes at infall, do not show substantial mass loss due to tides. When additionally comparing the orbital motion of the host subaloes to the measured proper motion of Fornax we find the matching more difficult; host subhaloes tend to have pericentres smaller than that measured ones for Fornax itself. From the kinematic and orbital data, we estimate that Fornax has lost 10 − 20% of its infall stellar mass. Our best estimate for the surface brightness of a stellar tidal stream associated with Fornax is Σ ∼ 32.6 mag arcsec −2 , which may be detectable with deep imaging surveys such as DES and LSST.

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Section: Orbital Motionsmentioning

confidence: 81%

Tidal features of classical Milky Way satellites in a Λ cold dark matter universe

Wang

Fattahi

Cooper

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…Right column: Individual pdfs marginalised over the other two components. The measurements from Piatek et al (2006) are shown in red, while those by Schweitzer et al (1995) are shown in blue. The vertical lines in the right panels and the dot in the left panels indicate the maximum likelihood values.…”

Section: Appendix B: Centre Of Mass Velocity Of Sculptormentioning

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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“…The Carina dSph was discovered in 1977 [7]. The best estimates of the orbits of the two dSphs show that Carina is likely to be more tidally disrupted than Sculptor [8,9], leading to higher uncertainties for the DM content of the Carina dSph than of the Sculptor.…”

Section: Introductionmentioning

confidence: 99%

H.E.S.S. constraints on dark matter annihilations towards the sculptor and carina dwarf galaxies

Abramowski¹,

Acero²,

Aharonian³

et al. 2011

Astroparticle Physics

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The Sculptor and Carina Dwarf spheroidal galaxies were observed with the H.E.S.S. Cherenkov telescope array between January 2008 and December 2009. The data sets consist of a total of 11.8 and 14.8 hours of high quality data, respectively. No gamma-ray signal was detected at the nominal positions of these galaxies above 220 GeV and 320 GeV, respectively. Upper limits on the gamma-ray fluxes at 95% C.L. assuming two forms for the spectral energy distribution (a power law shape and one derived from dark matter annihilation) are obtained at the level of 10 −13 to 10 −12 cm −2 s −1 in the TeV range. Constraints on the velocity weighted dark matter particle annihilation cross section for both Sculptor and Carina dwarf galaxies range from σv ∼ 10 −21 cm 3 s −1 down to σv ∼ 10 −22 cm 3 s −1 depending on the dark 3 matter halo model used. Possible enhancements of the gamma-ray flux are studied: the Sommerfeld effect, which is found to exclude some dark matter particle masses, the internal Bremsstrahlung and clumps in the dark-matter halo distributions.

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Proper Motions of Dwarf Spheroidal Galaxies fromHubble Space TelescopeImaging. IV. Measurement for Sculptor

Cited by 90 publications

References 46 publications

Tidal features of classical Milky Way satellites in a Λ cold dark matter universe

Tidal features of classical Milky Way satellites in a Λ cold dark matter universe

Orbit-based dynamical models of the Sculptor dSph galaxy

H.E.S.S. constraints on dark matter annihilations towards the sculptor and carina dwarf galaxies

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