Charting the Galactic acceleration field I. A search for stellar streams with Gaia DR2 and EDR3 with follow-up from ESPaDOnS and UVES

Ibata, Rodrigo; Malhan, Khyati; Martin, Nicolas; Aubert, Dominique; Famaey, Benoit; Bianchini, Paolo; Monari, Giacomo; Siebert, Arnaud; Thomas, Guillaume F.; Bellazzini, Michele; Bonifacio, Piercarlo; Caffau, Elisabetta; Renaud, Florent

doi:10.48550/arxiv.2012.05245

Cited by 8 publications

(13 citation statements)

References 47 publications

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“…This new GC, VVV-CL160, is also located in the extension of the Hrid halo stellar stream, with consistent PMs, metallicities, and distances. Ibata et al (2020) computed the orbit of the Hrid stream, and the kinematics of both GCs, , are similar to those expected for the Hrid stream extended into the Galactic bulge region (see their Fig. 8).…”

Section: Possible Link With the Hrid Halo Streamsupporting

confidence: 68%

“…The Hrid halo stream was recently discovered by Ibata et al (2020) as a thin stream located relatively nearby (D ∼ 3.1 kpc). Its member stars can be traced across 62 deg at intermediate Galactic latitudes (10 < b < 25 deg) in the northern hemisphere before the contrast is lost and it disappears at low lat-itudes.…”

Section: Possible Link With the Hrid Halo Streammentioning

confidence: 99%

“…Its member stars can be traced across 62 deg at intermediate Galactic latitudes (10 < b < 25 deg) in the northern hemisphere before the contrast is lost and it disappears at low lat-itudes. Follow-up spectroscopy of three member stars gives a mean metallicity of [Fe/H] = −1.1 (Ibata et al 2020).…”

Section: Possible Link With the Hrid Halo Streammentioning

confidence: 99%

“…Kinematically cold stellar streams are long and thin tracers of the halo (Helmi & White 1999;Combes et al 1999;Carlberg & Grillmair 2013). The recent discoveries of a number of these halo streams have helped to trace the history of mergers of infalling globular clusters (GCs) and dwarf galaxies that continue to build the Milky Way (MW; Grillmair 2017; Bonaca & Hogg 2018;Price-Whelan & Bonaca 2018;Helmi et al 2018;Mateu et al 2018;Carlberg 2018;Malhan et al 2018;Koposov et al 2019;Conroy et al 2019;Naidu et al 2020;Ibata et al 2020;Caldwell et al 2020;Bonaca et al 2021). It is important to constrain the properties of the individual stream progenitors (GCs vs. dwarf galaxies).…”

Section: Introductionmentioning

confidence: 99%

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Discovery of a new nearby globular cluster with extreme kinematics located in the extension of a halo stream

Minniti

Fernández-Trincado

Gómez

et al. 2021

A&A

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Context. We report the discovery of VVV-CL160, a new nearby globular cluster (GC) with extreme kinematics, located in the Galactic plane at l = 10.1477 deg, b = 0.2999 deg. Aims. We aim to characterize the physical properties of this new GC and place it in the context of the Milky Way, exploring its possible connection with the known GC NGC 6544 and with the Hrid halo stream. Methods. VVV-CL160 was originally detected in the VISTA Variables in the Vía Láctea (VVV) survey. We use the proper motions (PMs) from the updated VVV Infrared Astrometric Catalog (VIRAC2) to select GC members and make deep near-infrared color-magnitude diagrams to study the cluster properties. We also fit King models to the decontaminated sample to determine the GC structural parameters. Results. VVV-CL160 has an unusually large PM for a Galactic GC as measured with VIRAC2 and Gaia EDR3: μα cos (δ) = −2.3 ± 0.1 mas yr−1 and μδ = −16.8 ± 0.1 mas yr−1. The kinematics are similar to those of the known GC NGC 6544 and the Hrid halo stream. We estimate a reddening of E(J − K) = 1.95 mag and an extinction of AK = 1.40 mag for VVV-CL160. We also measure a distance modulus of (m − M) = 13.01 mag and a distance of D⊙ = 4.0 ± 0.5 kpc. This places the GC at z = 29 pc above the Galactic plane and at a galactocentric distance of RG = 4.2 kpc. We also measure a metallicity of [Fe/H] = −1.4 ± 0.2 dex for an adopted age of t = 12 Gyr; King model fits of the PM-decontaminated sample reveal a concentrated GC, with core radius rc = 22.8″ and tidal radius rt = 50′. We also estimate the absolute magnitude in the near-infrared of MK = −7.6 mag, equivalent to an optical absolute magnitude of MV = −5.1 mag. We also explore the possible association of this new GC with other GCs and halo streams. Conclusions. Based on the locations and kinematics, we suggest that VVV-CL160, along with NGC 6544, may be associated with the extension of the Hrid halo stream.

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Section: Possible Link With the Hrid Halo Streamsupporting

confidence: 68%

Section: Possible Link With the Hrid Halo Streammentioning

confidence: 99%

Section: Possible Link With the Hrid Halo Streammentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Discovery of a new nearby globular cluster with extreme kinematics located in the extension of a halo stream

Minniti

Fernández-Trincado

Gómez

et al. 2021

A&A

View full text Add to dashboard Cite

show abstract

“…Depending on the stream, perturbations induced by baryonic objects, subleading for our GD-1-like case, may be relevant and needed to be modeled accurately as they may induce similar effects as DM subhalo objects of large mass. Current observations from the GAIA and Dark Energy Survey (DES) missions are increasingly improving data about known streams and discovering new streams (Li et al 2019;Ibata et al 2020), that will be further complemented with upcoming observations such as DESI (DESI Collaboration et al 2016) and the Rubin Observatory (Ivezić et al 2019), which provide new promising ground for dark matter constraints.…”

Section: Discussionmentioning

confidence: 99%

Mass classification of dark matter perturbers of stellar tidal streams

Montanari,

García-Bellido

2020

Preprint

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Stellar streams formed by tidal stripping of progenitors orbiting around the Milky Way are expected to be perturbed by encounters with dark matter subhalos. Recent studies have shown that they are an excellent proxy to infer properties of the perturbers, such as their mass. Here we present two different methodologies that make use of the fully non-Gaussian density distribution of stellar streams: a Bayesian model selection based on the probability density function (PDF) of stellar density, and a likelihood-free gradient boosting classifier. As an application, we forecast model selection strength of evidence for cold dark matter clusters of masses 10 3 -10 5 𝑀 , 10 5 -10 7 𝑀 and 10 7 -10 9 𝑀 , based on a GD-1-like stellar stream and including realistic observational errors. Evidence for the smaller mass range, so far under-explored, is particularly interesting for the primordial black holes cold dark matter hypothesis. We expect moderate to strong evidence for model selection based on the PDF analysis when assuming low and intermediate dark matter perturbers mass ranges as fiducial models, but only weak evidence when the larger mass range is taken to be the fiducial model. Instead, the gradient boosting model is a highly efficient classifier (𝐹 1 -scores larger than 90%) for all mass ranges here considered.

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Mass classification of dark matter perturbers of stellar tidal streams

Montanari

García-Bellido

2022

Physics of the Dark Universe

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Charting the Galactic acceleration field I. A search for stellar streams with Gaia DR2 and EDR3 with follow-up from ESPaDOnS and UVES

Cited by 8 publications

References 47 publications

Discovery of a new nearby globular cluster with extreme kinematics located in the extension of a halo stream

Discovery of a new nearby globular cluster with extreme kinematics located in the extension of a halo stream

Mass classification of dark matter perturbers of stellar tidal streams

Mass classification of dark matter perturbers of stellar tidal streams

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