Stellar envelopes of globular clusters embedded in dark mini-haloes

Peñarrubia, Jorge; Varri, Anna Lisa; Breen, Philip G.; Ferguson, Annette M. N.; Sánchéz-Janssen, R.

doi:10.1093/mnrasl/slx094

Cited by 54 publications

(62 citation statements)

References 36 publications

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“…Thus, the cosmological star formation would be processed, in part, in structures similar to globular clusters. The presence of non-baryonic dark matter in globular clusters has recently been discussed by Sollima et al (2016) and Peñarrubia et al (2017). Our work shows consistency with the results and analyses of these authors.…”

Section: Discussionsupporting

confidence: 93%

Connecting the Cosmic Star Formation Rate with the Local Star Formation

Gribel¹,

Miranda²,

Vilas-Boas³

2017

ApJ

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We present a model that unifies the cosmic star formation rate (CSFR), obtained through the hierarchical structure formation scenario, with the (Galactic) local star formation rate (SFR). It is possible to use the SFR to generate a CSFR mapping through the density probability distribution functions (PDFs) commonly used to study the role of turbulence in the star-forming regions of the Galaxy. We obtain a consistent mapping from redshift z ∼ 20 up to the present (z = 0). Our results show that the turbulence exhibits a dual character, providing high values for the star formation efficiency ( ε ∼ 0.32) in the redshift interval z ∼ 3.5 − 20 and reducing its value to ε = 0.021 at z = 0. The value of the Mach number (M crit ), from which ε rapidly decreases, is dependent on both the polytropic index (Γ) and the minimum density contrast of the gas. We also derive Larson's first law associated with the velocity dispersion ( V rms ) in the local star formation regions. Our model shows good agreement with Larson's law in the ∼ 10 − 50 pc range, providing typical temperatures T 0 ∼ 10 − 80 K for the gas associated with star formation. As a consequence, dark matter halos of great mass could contain a number of halos of much smaller mass, and be able to form structures similar to globular clusters. Thus, Larson's law emerges as a result of the very formation of large-scale structures, which in turn would allow the formation of galactic systems, including our Galaxy.

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Section: Discussionsupporting

confidence: 93%

Connecting the Cosmic Star Formation Rate with the Local Star Formation

Gribel¹,

Miranda²,

Vilas-Boas³

2017

ApJ

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“…Other simulations show that tidal effects of the host galaxy can remove a large amount of the original DM inside GCs (Mashchenko & Sills 2005b). More recently, Peñarrubia et al (2017) showed that stars ejected due to hard encounters in the central region of GCs embedded in a DM halo generate an envelope of gravitationally bounded stars. Supporting this model, so-called extratidal stars have been observed in many GCs of the MW (e.g., Carballo-Bello et al 2012, 2018 and the Andromeda galaxy .…”

Section: Dm In Gcsmentioning

confidence: 99%

A MegaCam Survey of Outer Halo Satellites. VII. A Single Sérsic Index versus Effective Radius Relation for Milky Way Outer Halo Satellites* †

Marchi-Lasch

Muñoz

Santana

et al. 2019

ApJ

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In this work, we use structural properties of the Milky Way's outer halo (R G >25 kpc) satellites (dwarf spheroidal galaxies, ultra-faint dwarf (UFD) galaxies and globular clusters (GCs)) derived from deep, wide-field, and homogeneous data to present evidence of a correlation in the Sérsic index versus effective radius plane followed by a large fraction of outer halo GCs and satellite dwarf galaxies. We show that this correlation can be entirely reproduced by fitting empirical relations in the central surface brightness versus absolute magnitude and Sérsic index versus absolute magnitude parameter spaces, and by assuming the existence of two types of outer halo GCs: one of high surface brightness (HSB group), with properties similar to those of inner halo clusters; and another of low surface brightness (LSB group), which share characteristics with dwarf spheroidal and UFD galaxies. Given the similarities of LSB clusters with dwarf spheroidal and UFD galaxies, we discuss the possibility that outer halo clusters also originated inside dark matter halos and that tidal forces from different host galaxy potentials are responsible for the different properties between HSB and LSB clusters.

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“…Leaman et al 2013;Massari et al 2019); yet it is still unclear whether they originated in the early universe within dark matter mini-halos or simply as gravitationally bound clouds (e.g. Peebles 1984;Peñarrubia et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Exploring the Outskirts of Globular Clusters: The Peculiar Kinematics of NGC 3201

Bianchini

Ibata

Famaey

2019

ApJL

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The outskirts of globular clusters (GCs) simultaneously retain crucial information about their formation mechanism and the properties of their host galaxy. Thanks to the advent of precision astrometry both their morphological and kinematic properties are now accessible. Here we present the first dynamical study of the outskirts of the retrograde GC NGC3201 until twice its Jacobi radius (< 100 pc), using specifically-selected high-quality astrometric data from Gaia DR2. We report the discovery of a stellar overdensity along the South-East/North-West direction that we identify as tidal tails. The GC is characterized globally by radial anisotropy and a hint of isotropy in the outer parts, with an excess of tangential orbits around the lobes corresponding to the tidal tails, in qualitative agreement with an N -body simulation. Moreover, we measure flat velocity dispersion profiles, reaching values of 3.5 ± 0.9 km s −1 until beyond the Jacobi radius. While tidal tails could contribute to such a flattening, this high velocity dispersion value is in disagreement with the expectation from the sole presence of potential escapers. To explain this puzzling observation, we discuss the possibility of an accreted origin of the GC, the presence of a dark matter halo -leftover of its formation at high redshift -and the possible effects of non-Newtonian dynamics. Our study uncovers a new path for the study of GC formation and of the properties of the Milky Way potential in the era of precision astrometry.

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Stellar envelopes of globular clusters embedded in dark mini-haloes

Cited by 54 publications

References 36 publications

Connecting the Cosmic Star Formation Rate with the Local Star Formation

Connecting the Cosmic Star Formation Rate with the Local Star Formation

A MegaCam Survey of Outer Halo Satellites. VII. A Single Sérsic Index versus Effective Radius Relation for Milky Way Outer Halo Satellites* †

Exploring the Outskirts of Globular Clusters: The Peculiar Kinematics of NGC 3201

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