Streams on FIRE: Populations of Detectable Stellar Streams in the Milky Way and FIRE

Shipp, Nora; Panithanpaisal, Nondh; Necib, Lina; Sanderson, Robyn E.; Erkal, Denis; Li, Ting S.; Santistevan, Isaiah; Wetzel, Andrew; Cullinane, Lara R.; Ji, Alexander P.; Koposov, S. E.; Kuêhn, K.; Lewis, Geraint F.; Pace, Andrew B.; Zucker, D. B.; Bland-Hawthorn, Joss; Cunningham, Emily C.; Kim, Stacy; Lilleengen, Sophia; Moreno, Jorge; Sharma, Sanjib

doi:10.3847/1538-4357/acc582

“…These stars would naturally be susceptible to tidal influences when the tidal radius is much larger than the half-light radius, which in turn allows tidal influence to shape UFDs at larger ρ 1/2 /ρ MW (r = r peri ). Low surface brightness tidal features around some Milky Way satellites have been predicted by recent simulations (e.g., Shipp et al 2023).…”

Section: Hercules In the Big Picturementioning

confidence: 52%

Signatures of Tidal Disruption of the Hercules Ultrafaint Dwarf Galaxy*

Ou 欧,

Chiti,

Shipp

et al. 2024

ApJ

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The Hercules ultrafaint dwarf galaxy (UFD) has long been hypothesized to be tidally disrupting, yet no conclusive evidence has been found for tidal disruption owing partly to difficulties in identifying Hercules member stars. In this work, we present a homogeneous reanalysis of new and existing observations of Hercules, including the detection of a new potential member star located ∼1° (∼1.7 kpc) west of the center of the system. In addition to measuring the line-of-sight velocity gradient, we compare predictions from dynamical models of stream formation to these observations. We report an updated velocity dispersion measurement based on 28 stars, 1.9 − 0.6 + 0.6 km s−1, which is significantly lower than previous measurements. We find that the line-of-sight velocity gradient is 1.8 − 1.8 + 1.8 km s−1 kpc along the major axis of Hercules, consistent with zero within 1σ. Our dynamical models of stream formation, on the other hand, can reproduce the morphology of the Hercules UFD, specifically the misalignment between the elongation and the orbital motion direction. Additionally, these dynamical models indicate that any radial velocity gradient from tidal disruption would be too small, 0.00 − 0.91 + 0.97 km s−1 kpc, to be detectable with current sample sizes. Combined with our analysis of the tidal radius evolution of the system as a function of its orbital phase, we argue that it is likely that Hercules is indeed currently undergoing tidal disruption in its extended stellar halo with a line-of-sight velocity gradient too small to be detected with current observational data sets.

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“…In particular, the internal dynamics of small-scale structures such as satellite galaxies and stellar streams are sensitive to the choice of kernel. Studies of small-scale MW structures therefore required careful kernel selection based on the science question at hand; Shipp et al (2023), for example, changed the kernel to be able to perform detectability studies of stellar streams with LSST.…”

Section: Use Cases and Limitationsmentioning

confidence: 99%

“…Sanderson et al (2020, hereafter S20) produced nine Gaia DR2 synthetic surveys of the Latte suite of simulations (Wetzel & Hopkins 2016;Hopkins et al 2018), using the code Ananke. Such synthetic surveys have been used in many studies involving the dynamics of the MW, for example to estimate the detectability of simulated stellar streams (Shipp et al 2023), as a training set for a neural network that built the first catalog of accreted stars in the MW (Ostdiek et al 2020), leading to the discovery of the prograde local structure Nyx (Necib et al 2020), as a framework to test the ability of unsupervised machine learning techniques to reproduce the stellar phase-space density (Buckley et al 2023), and as a link to connect the formation history and the components of the MW (Belokurov et al 2020). In this work, we present synthetic Gaia DR3 surveys based on the same suite of Latte simulations.…”

Section: Introductionmentioning

confidence: 99%

“…The framework entails sampling a population of individual stars from simulated star particles, assigning them realistic physical properties, and applying a simple error model to produce mock observations. Ananke has been applied to produce mock observations of other surveys from a range of simulated data sets, such as APOGEE (Beaton et al 2022), Dark Energy Survey (DES Collaboration 2005, and the Rubin Observatory Legacy Survey of Space and Time (LSST; Ivezić et al 2019) in Shipp et al (2023).…”

Section: Introductionmentioning

confidence: 99%

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Synthetic Gaia DR3 Surveys from the FIRE Cosmological Simulations of Milky Way-mass Galaxies

Nguyen,

Ou,

Panithanpaisal

et al. 2024

ApJ

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The third data release (DR3) of Gaia has provided a fivefold increase in the number of radial velocity measurements of stars, as well as a stark improvement in parallax and proper motion measurements. To help with studies that seek to test models and interpret Gaia DR3, we present nine Gaia synthetic surveys, based on three solar positions in three Milky Way-mass galaxies of the Latte suite of the Fire-2 cosmological simulations. These synthetic surveys match the selection function, radial velocity measurements, and photometry of Gaia DR3, adapting the code base Ananke, previously used to match the Gaia DR2 release by Sanderson et al. The synthetic surveys are publicly available and can be found at http://ananke.hub.yt/. Similarly to the previous release of Ananke, these surveys are based on cosmological simulations and thus are able to model nonequilibrium dynamical effects, making them a useful tool in testing and interpreting Gaia DR3.

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“…Dwarf galaxies are the fundamental building blocks of larger structures. They are the most abundant type of galaxies in the Universe at all redshifts (e.g., Binggeli et al 1988;Ferguson & Binggeli 1994;Marzke & da Costa 1997), and the dwarf galaxies of the Local Group are well studied both observationally (McConnachie 2012; York et al 2012;Martin et al 2016;Albareti et al 2017;Abbott et al 2018;Aguado et al 2019) and theoretically (Hopkins et al 2018;Pandya et al 2020;Applebaum et al 2021;Shipp et al 2023;Weerasooriya et al 2023).…”

Section: Introductionmentioning

confidence: 99%

Devouring the Centaurus A Satellites: Modeling Dwarf Galaxies with Galacticus

Weerasooriya,

Bovill,

Taylor

et al. 2024

ApJ

1

0

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For the first time, systematic studies of dwarf galaxies are being conducted throughout the Local Volume, including the dwarf satellites of the nearby giant elliptical galaxy Centaurus A (NGC 5128). Given Centaurus A's mass (roughly 10 times larger than that of the Milky Way), AGN activity, and recent major mergers, investigating the dwarf galaxies of Centaurus A and their star formation physics is imperative. However, simulating the faintest dwarfs around a galaxy of Centaurus A's mass with sufficient resolution in a hydrodynamic simulation is computationally expensive and currently infeasible. In this study, we seek to reproduce the properties of Centaurus A dwarfs using the semianalytic model Galacticus to model dwarfs within a 700 kpc region around Centaurus A, corresponding approximately to its splashback radius. We investigate the effects of host halo mass and environment and predict observable properties of Centaurus A dwarfs using astrophysical prescriptions and parameters previously tuned to match properties of the Milky Way’s satellite galaxies. This approach allows us to approximately replicate cumulative luminosity functions, and luminosity–metallicity and luminosity–half-light-radii relations observed in the Centaurus A satellites. We provide predictions for the velocity dispersions, and star formation histories of Centaurus A dwarfs. The agreement between our predicted star formation histories for Centaurus A dwarfs and those of the Milky Way dwarfs implies the presence of universal processes governing star formation in dwarf galaxies. Overall, our findings shed light on the star formation physics of dwarf galaxies in the Centaurus A system, revealing insights into their properties and dependence on the host environment.

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Streams on FIRE: Populations of Detectable Stellar Streams in the Milky Way and FIRE

Cited by 17 publications

References 143 publications

Signatures of Tidal Disruption of the Hercules Ultrafaint Dwarf Galaxy*

Signatures of Tidal Disruption of the Hercules Ultrafaint Dwarf Galaxy*

Synthetic Gaia DR3 Surveys from the FIRE Cosmological Simulations of Milky Way-mass Galaxies

Devouring the Centaurus A Satellites: Modeling Dwarf Galaxies with Galacticus

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