The effect of tides on the Sculptor dwarf spheroidal galaxy

Iorio, Giuliano; Nipoti, Carlo; Battaglia, G.; Sollima, A.

doi:10.1093/mnras/stz1342

Cited by 22 publications

(14 citation statements)

References 144 publications

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“…While some of the most massive MW dSphs, such as Fornax and Sculptor, seem to have too large of orbits to be significantly affected by tidal stripping (Battaglia et al 2015;Iorio et al 2019), there is some support for the notion that other MW dSphs have been affected by tidal stripping (Majewski et al 2002;Muñoz et al 2006;Sohn et al 2007;Battaglia et al 2012;Roderick et al 2015Roderick et al , 2016, and with that stripping preferentially removing older, more metal-poor populations to shape the overall present-day metallicity distribution functions (Majewski et al 2002;Muñoz et al 2006;Chou et al 2007;Law & Majewski 2010;Sales et al 2010;Battaglia et al 2012). If this is true, then present-day dwarfs may have smaller radial metallicity variations than in the past, because they have also experienced some tidal evolution, albeit not as strongly as Sgr.…”

Section: Discussionmentioning

confidence: 99%

Metallicity and α-Element Abundance Gradients along the Sagittarius Stream as Seen by APOGEE

Hayes

Majewski

Hasselquist

et al. 2020

ApJ

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Using 3D positions and kinematics of stars relative to the Sagittarius (Sgr) orbital plane and angular momentum, we identify 166 Sgr stream members observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) that also have Gaia DR2 astrometry. This sample of 63/103 stars in the Sgr trailing/leading arm is combined with an APOGEE sample of 710 members of the Sgr dwarf spheroidal core (385 of them newly presented here) to establish differences of 0.6 dex in median metallicity and 0.1 dex in [α/Fe] between our Sgr core and dynamically older stream samples. Mild chemical gradients are found internally along each arm, but these steepen when anchored by core stars. With a model of Sgr tidal disruption providing estimated dynamical ages (i.e., stripping times) for each stream star, we find a mean metallicity gradient of 0.12±0.03 dex Gyr −1 for stars stripped from Sgr over time. For the first time, an [α/Fe] gradient is also measured within the stream, at 0.02±0.01 dex Gyr −1 using magnesium abundances and at 0.04±0.01 dex Gyr −1 using silicon, which imply that the Sgr progenitor had significant radial abundance gradients. We discuss the magnitude of those inferred gradients and their implication for the nature of the Sgr progenitor within the context of the current family of Milky Way satellite galaxies, and we suggest that more sophisticated Sgr models are needed to properly interpret the growing chemodynamical detail we have on the Sgr system. Unified Astronomy Thesaurus concepts: Sagittarius dwarf spheroidal galaxy (1423); Milky Way stellar halo (1060); Chemical abundances (224); Galaxy evolution (594); Tidal tails (1701); Galaxy chemical evolution (580); Galaxy abundances (574); Stellar kinematics (1608); Stellar abundances (1577); Dwarf galaxies (416)

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Section: Discussionmentioning

confidence: 99%

Metallicity and α-Element Abundance Gradients along the Sagittarius Stream as Seen by APOGEE

Hayes

Majewski

Hasselquist

et al. 2020

ApJ

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“…et al 2018), as the derived pericentre of these two galaxies are both 50 kpc and N -body simulations on the effects of tides based on observationally motivated orbits on both Sculptor (Iorio et al 2019) and Fornax (Battaglia, Sollima & Nipoti 2015).…”

Section: Tangential Velocity Anisotropy In An Evolutionary Context Fo...mentioning

confidence: 99%

“…First of all, the similarity of βr between these dSphs and an isolated dIrr implies that the negative βr seen in dSphs needs not be a result of tidal stripping. The orbital information of both Sculptor and Fornax inferred from proper motion measurements done with GAIA also have weakened the case that they have been tidally stripped (Fritz et al 2018), as the derived pericentre of these two galaxies are both 50 kpc and N -body simulations on the effects of tides based on observationally motivated orbits on both Sculptor (Iorio et al 2019) and Fornax (Battaglia, Sollima & Nipoti 2015).…”

Section: Tangential Velocity Anisotropy In An Evolutionary Context For Dwarf Galaxiesmentioning

confidence: 99%

Joint gas and stellar dynamical models of WLM: an isolated dwarf galaxy within a cored, prolate DM halo

Leung

Leaman

Battaglia

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We present multi-tracer dynamical models of the low mass (M* ∼ 107), isolated dwarf irregular galaxy WLM in order to simultaneously constrain the inner slope of the dark matter (DM) halo density profile (γ) and flattening (qDM), and the stellar orbital anisotropy (βz, βr). For the first time, we show how jointly constraining the mass distribution from the HI gas rotation curve and solving the Jeans’ equations with discrete stellar kinematics leads to a factor of ∼2 reduction in the uncertainties on γ. The mass-anisotropy degeneracy is also partially broken, leading to reductions on uncertainty by $\sim 30\%$ on Mvir (and $\sim 70\%$ at the half-light radius) and $\sim 25\%$ on anisotropy. Our inferred value of γ = 0.3 ± 0.1 is robust to the halo geometry, and in excellent agreement with predictions of stellar feedback driven DM core creation. The derived prolate geometry of the DM halo with qDM = 2 ± 1 is consistent with ΛCDM simulations of dwarf galaxy halos. While self-interacting DM (SIDM) models with σ/mX ∼ 0.6 can reproduce this cored DM profile, the interaction events may sphericalise the halo. The simultaneously cored and prolate DM halo may therefore present a challenge for SIDM. Finally we find that the radial profile of stellar anisotropy in WLM (βr) follows a nearly identical trend of increasing tangential anisotropy to the classical dSphs, Fornax and Sculptor. Given WLM’s orbital history, this result may call into question whether such anisotropy is a consequence of tidal stripping in only one pericentric passage or if it instead is a feature of the largely self-similar formation and evolutionary pathways for some dwarf galaxies.

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“…the impact of ram-pressure stripping and tidal effects onto their gas content, star formation history (SFH), morphology and dark matter (DM) halo properties (e.g. Mayer et al 2006;Muñoz et al 2008;Kazantzidis et al 2011;Battaglia et al 2015;Hausammann et al 2019;Iorio et al 2019;Miyoshi & Chiba 2020;Ruiz-Lara et al 2021;Rusakov et al 2021;Di Cintio et al 2021;Genina et al 2020, and references therein).…”

Section: Introductionmentioning

confidence: 99%

Gaia early DR3 systemic motions of Local Group dwarf galaxies and orbital properties with a massive Large Magellanic Cloud

Battaglia,

Taibi,

Thomas

et al. 2021

Preprint

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Aims. We perform a comprehensive determination of the systemic proper motions of 74 dwarf galaxies and dwarf galaxy candidates in the Local Group based on Gaia early data release 3. The outputs of the analysis for each galaxy, including probabilities of membership, will be made publicly available. The analysis is augmented by a determination of the orbital properties of galaxies within 500 kpc. Methods. We adopt the flexible Bayesian methodology presented by McConnachie & Venn (2020), which takes into account the location of the stars on the sky, on the colour-magnitude diagram and on the proper motion plane. We apply some modifications, in particular to the way the colour-magnitude diagram and spectroscopic information are factored in, e.g. by including stars in several evolution phases. The bulk motions are integrated in three gravitational potentials: two where the Milky Way is treated in isolation and has a mass 0.9 & 1.6 ×10 12 M and the time-varying potential by Vasiliev et al. ( 2021), which includes the infall of a massive Large Magellanic Cloud (LMC). Results. We are able to determine bulk proper motions for 73 systems, and we consider reliable 66 of these measurements. For the first time, systemic motions are presented for galaxies out to a distance of 1.4 Mpc, in the NGC 3109 association. The inclusion of the infall of a massive LMC significantly modifies the orbital trajectories of the objects, with respect to orbit integration in static Milky Way-only potentials, and leads to 6 galaxies being likely associated to the LMC, 3 possibly associated and 1 recently captured object. We discuss the results of the orbit integration in the context of the relation of the galaxies to the system of Milky Way satellites, implications for the too-big-to-fail problem, impact on star formation histories, and tidal disruption.

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The effect of tides on the Sculptor dwarf spheroidal galaxy

Cited by 22 publications

References 144 publications

Metallicity and α-Element Abundance Gradients along the Sagittarius Stream as Seen by APOGEE

Metallicity and α-Element Abundance Gradients along the Sagittarius Stream as Seen by APOGEE

Joint gas and stellar dynamical models of WLM: an isolated dwarf galaxy within a cored, prolate DM halo

Gaia early DR3 systemic motions of Local Group dwarf galaxies and orbital properties with a massive Large Magellanic Cloud

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