English
Related papers

Related papers: The SEGUE K Giant Survey. III. Quantifying Galacti…

200 papers

We use recent SEGUE spectroscopy and SDSS and SEGUE imaging data to measure the sky position, distance, and radial velocities of stars in the tidal debris stream that is commonly referred to as the "Orphan Stream." We fit orbital parameters…

Astrophysics of Galaxies · Physics 2014-11-20 Heidi Jo Newberg , Benjamin A. Willett , Brian Yanny , Yan Xu

We explore the origin of the observed decline in [O/Fe] (and [Mg/Fe]) with Galactocentric distance for high-metallicity stars ([Fe/H] > -1.1), based on a sample of halo stars selected within the Apache Point Observatory Galactic Evolution…

In order to construct a catalogue of oxygen-rich (noted M) asymptotic giant branch (AGB) stars in the halo, complementing those of carbon-rich (C) stars, previous lists of Miras and SRa semiregulars located in the nor thern hemisphere are…

Astrophysics of Galaxies · Physics 2019-06-26 Nicolas Mauron , Luc P. A. Maurin , Tim R. Kendall

The star formation histories (SFHs) of galactic stellar haloes offer crucial insights into the merger history of the galaxy and the effects of those mergers on their hosts. Such measurements have revealed that while the Milky Way's most…

We present the results of fitting a flexible stellar stream density model to a collection of thirteen streams around the Milky Way, using photometric data from DES, DECaLS, and Pan-STARRS. We construct density maps for each stream and…

Astrophysics of Galaxies · Physics 2022-06-22 Jeffrey M. Patrick , Sergey E. Koposov , Matthew G. Walker

Recent advances from astronomical surveys have revealed spatial, chemical, and kinematical inhomogeneities in the inner region of the stellar halo of the Milky Way Galaxy. In particular, large spectroscopic surveys, combined with Gaia…

Astrophysics of Galaxies · Physics 2020-07-08 Deokkeun An , Timothy C. Beers

The inner Galactic halo is a complex graveyard of the Milky Way's earliest accretion events, where severe orbital phase-mixing challenges traditional dynamical stream-finding techniques. We present a purely data-driven, 12-dimensional…

Astrophysics of Galaxies · Physics 2026-05-25 Furkan Akbaba , Olcay Plevne

We present the results of a detailed abundance analysis of one of the confirmed building blocks of the Milky Way stellar halo, a kinematically-coherent metal-poor stellar stream. We have obtained high resolution and high S/N spectra of 12…

Astrophysics of Galaxies · Physics 2015-05-14 Ian U. Roederer , Christopher Sneden , Ian B. Thompson , George W. Preston , Stephen A. Shectman

Population-level studies of Milky Way satellites used to constrain dark matter or the threshold of galaxy formation often rely on velocity dispersions and metallicities derived from heterogeneous spectroscopic analyses. Systematic…

Astrophysics of Galaxies · Physics 2026-02-12 Marla Geha

We examine the HI content and environment of all of the Local Group dwarf galaxies (M_tot < 10^10 M_solar), including the numerous newly discovered satellites of the Milky Way and M31. All of the new dwarfs, with the exception of Leo T,…

Astrophysics of Galaxies · Physics 2016-06-02 Jana Grcevich , Mary E Putman

We present VLT-FORS1 spectra of a sample of 34 faint 20.0 < g* < 21.1 A-type stars selected from the Sloan Digital Sky Survey Early Data Release, with the goal of measuring the velocity dispersion of blue horizontal branch (BHB) stars in…

Astrophysics · Physics 2008-11-26 L. Clewley , S. J. Warren , P. C. Hewett , John. E. Norris , M. I. Wilkinson , N. W. Evans

We study the amount and distribution of dark matter substructures within dark matter haloes, using a large set of high-resolution simulations ranging from group size to cluster size haloes, and carried our within a cosmological model…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 E. Contini , G. De Lucia , S. Borgani

Based on 4,\,098 very metal-poor (VMP) stars with 6D phase-space and chemical information from \textit{Gaia} DR3 and LAMOST DR9 as tracers, we apply an unsupervised machine learning algorithm, Shared Nearest Neighbor (SNN), to identify…

Astrophysics of Galaxies · Physics 2023-12-14 Dashuang Ye , Cuihua Du , Jianrong Shi , Jun Ma

The spiral structure of the Milky Way is not yet well determined. The keys to understanding this structure are to increase the number of reliable spiral tracers and to determine their distances as accurately as possible. HII regions, giant…

Astrophysics of Galaxies · Physics 2014-10-15 L. G. Hou , J. L. Han

Using G dwarfs from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) survey, we have determined a vertical metallicity gradient over a large volume of the Milky Way's disk, and examined how this gradient varies for…

We determine the average metallicities of the elements of cold halo substructure (ECHOS) that we previously identified in the inner halo of the Milky Way within 17.5 kpc of the Sun. As a population, we find that stars kinematically…

Astrophysics of Galaxies · Physics 2015-05-27 Kevin C. Schlaufman , Constance M. Rockosi , Young Sun Lee , Timothy C. Beers , Carlos Allende Prieto

Simulations are run with and without a normal cold dark matter sub-halo population below 4x10^8 M_sun to examine the role of the lower mass sub-halos in the creation of density variations, "gaps", within thin tidal star streams. Dense star…

Astrophysics of Galaxies · Physics 2021-01-20 Raymond G. Carlberg

We demonstrate that there is a clear statistical correlation between the (X,Y,Z,V_r) phase-space distribution of the outer halo Galactic globular clusters (having 10 kpc <= R_GC <= 40 kpc) and the orbital path of the Sagittarius dwarf…

Astrophysics · Physics 2009-11-07 Michele Bellazzini , Francesco R. Ferraro , Rodrigo Ibata

We present a search for new members of the 300 km s$^{-1}$ stream (300S) near the dwarf galaxy Segue 1 using wide-field survey data. We identify 11 previously unknown bright stream members in the APOGEE-2 and SEGUE-1 and 2 spectroscopic…

The SEGUE survey obtained 240,000 moderate resolution (R = 1800) spectra from 3900 - 9000 Angstroms of fainter Milky Way stars (14.0 < g < 20.3) of a wide variety of spectral types, both main sequence and evolved objects, with the goal of…

Astrophysics of Galaxies · Physics 2012-08-27 II SEGUE Collaboration , Brian Yanny , Constance Rockosi , Heidi Jo Newberg , Gillian R. Knapp