English
Related papers

Related papers: Blind source separation of the stellar halo

200 papers

We study the mass spectrum of destroyed dwarfs that contribute to the accreted stellar mass of Milky Way (MW) mass M_vir ~ 10^12.1 M_sun) halos using a suite of 45 zoom-in, dissipationless simulations. Empirical models are employed to…

Astrophysics of Galaxies · Physics 2016-04-20 Alis J. Deason , Yao-Yuan Mao , Risa H. Wechsler

It is essential to examine the physical or chemical properties of molecular gas in starburst galaxies to reveal the underlying mechanisms characterizing starbursts. We used non-negative matrix factorization (NMF) to extract individual…

The standard cosmological scenario predicts a hierarchical formation for galaxies. Many substructures were found in the Galactic halo, identified as clumps in kinematic spaces, like the energy-angular momentum one (E-Lz), under the…

Astrophysics of Galaxies · Physics 2024-10-09 Alice Mori , Paola Di Matteo , Stefania Salvadori , Sergey Khoperskov , Giulia Pagnini , Misha Haywood

We test the hypothesis that the classical and ultra-faint dwarf spheroidal satellites of the our Galaxy have been the building blocks of the Galactic halo by comparing their [O/Fe] and [Ba/Fe] vs. [Fe/H] patterns with the ones observed in…

Astrophysics of Galaxies · Physics 2018-08-22 E. Spitoni , F. Vincenzo , F. Matteucci , D. Romano

The halo stars on highly radial orbits should inevitably pass the center regions of the Milky Way. Under the assumption that the stellar halo is in dynamical equilibrium and axisymmetric, we integrate the orbits of $\sim 10,000$ halo…

Astrophysics of Galaxies · Physics 2022-11-16 Chengqun Yang , Ling Zhu , Behzad Tahmasebzadeh , Xiang-Xiang Xue , Chao Liu

Theory and observations agree that the accreted stellar halos (ASHs) of Milky Way-like galaxies display significant scatter. I take advantage of this stochasticity to invert the link between halo assembly history (HAH) and ASH, using mock…

Astrophysics of Galaxies · Physics 2017-05-31 Nicola C. Amorisco

We investigate the diffuse light (DL) content of dark matter haloes in the mass range $11.5\leq \log M_{halo}\leq13$, a range that includes also the dark matter halo of the Milky-Way, taking advantage of a state-of-the-art semi-analytic…

Astrophysics of Galaxies · Physics 2024-03-01 E. Contini , S. Han , S. Jeon , J. Rhee , S. K. Yi

Stellar halos around galaxies contain key information about their formation and assembly history. Using simulations, we can trace the origins of different stellar populations in these halos, contributing to our understanding of galaxy…

Accreted stellar populations are comprised of the remnants of destroyed galaxies, and often dominate the `stellar haloes' of galaxies such as the Milky Way (MW). This ensemble of external contributors is a key indicator of the past assembly…

Astrophysics of Galaxies · Physics 2023-03-01 Alis J. Deason , Sergey E. Koposov , Azadeh Fattahi , Robert J. J. Grand

If the favored hierarchical cosmological model is correct, then the Milky Way system should have accreted ~100-200 luminous satellite galaxies in the past \~12 Gyr. We model this process using a hybrid semi-analytic plus N-body approach…

Astrophysics · Physics 2008-11-26 James S. Bullock , Kathryn V. Johnston

We identify ten -- seven for the first time -- elements of cold halo substructure (ECHOS) in the volume within 17.5 kpc of the Sun in the inner halo of the Milky Way. Our result is based on the observed spatial and radial velocity…

Recent dynamical analysis based on Gaia data have revealed major accretion events in Milky Way's history. Nevertheless, our understanding of the primordial Galaxy is hindered because the bona fide identification of the most metal-poor and…

Currently only a small number of Milky Way (MW) stars are known to exist beyond 100 kpc from the Galactic center. Though the distribution of these stars in the outer halo is believed to be sparse, they can provide evidence of more recent…

Astrophysics of Galaxies · Physics 2017-08-02 Robyn E. Sanderson , Amy Secunda , Kathryn V. Johnston , John J. Bochanski

Based on the [Fe/H] versus [Mg/Fe] diagram and distances from APOGEE data release 14, we compare the spatial distributions, the l-Vlos diagram and the abundance gradients between high-[Mg/Fe] and low-[Mg/Fe] sequences. The two sequences are…

Astrophysics of Galaxies · Physics 2019-02-13 Y. Q. Chen , G. Zhao , X. X. Xue , J. K. Zhao , X. L. Liang , Y. P. Jia , C. Q. Yang

(Abridged) The hierarchical formation scenario for the stellar halo requires the accretion and disruption of dwarf galaxies, yet low-metallicity halo stars are enriched in alpha-elements compared to similar, low-metallicity stars in dwarf…

According to the current cosmological cold dark matter paradigm, the Galactic halo could have been the result of the assemblage of smaller structures. Here we explore the hypothesis that the classical and ultra-faint dwarf spheroidal…

Astrophysics of Galaxies · Physics 2016-03-23 E. Spitoni , F. Vincenzo , F. Matteucci , D. Romano

Small stellar systems like dwarf galaxies are suggested to be the main building blocks of our Galaxy by numerical simulations in Lambda CDM models. The existence of star streams like Sagittarius tidal stream indicates that dwarf galaxies…

Solar and Stellar Astrophysics · Physics 2019-05-13 Qian-Fan Xing , Gang Zhao , Wako Aoki , Satoshi Honda , Hai-Ning Li , Miho N. Ishigaki , Tadafumi Matsuno

We present a detailed study of the chemical diversity of the metal-poor Milky Way (MW) using data from the GALAH DR3 survey. Considering 17 chemical abundances relative to iron ([X/Fe]) for 9,923 stars, we employ Principal Component…

Astrophysics of Galaxies · Physics 2024-07-29 Nicole Buckley , Payel Das , Paula Jofré , Robert M. Yates , Keith Hawkins

We present a homogeneous set of accurate atmospheric parameters for a complete sample of very and extremely metal-poor stars in the dwarf spheroidal galaxies (dSphs) Sculptor, Ursa Minor, Sextans, Fornax, Bo\"otes I, Ursa Major II, and Leo…

Solar and Stellar Astrophysics · Physics 2017-08-30 L. Mashonkina , P. Jablonka , Yu. Pakhomov , T. Sitnova , P. North

The metallicity structure of stellar halos encodes the fossil record of galaxy assembly, tracing the chemical evolution and dynamical imprint of past mergers. Using five Milky Way-mass halos from the Aquarius simulations, we introduce an…

Astrophysics of Galaxies · Physics 2025-12-01 Amit Mondal , Biswajit Pandey