English
Related papers

Related papers: Triangulum II: Not Especially Dense After All

200 papers

We investigate the possibility that the dwarf galaxies Crater II and Hercules have previously been tidally stripped by the Milky Way. We present Magellan/IMACS spectra of candidate member stars in both objects. We identify 37 members of…

Astrophysics of Galaxies · Physics 2019-09-25 Sal Wanying Fu , Joshua D. Simon , Alex G. Alarcón Jara

The Milky Way is surrounded by dozens of ultra-faint (< $10^5$ solar luminosities) dwarf satellite galaxies. They are the surviving remnants of the earliest galaxies, as confirmed by their ancient (~13 billion years old) and chemically…

We present the stellar and gaseous kinematics of an Sb galaxy, NGC 3223, with the aim of determining the vertical and radial stellar velocity dispersion as a function of radius, which can help to constrain disk heating theories. Together…

Astrophysics of Galaxies · Physics 2015-04-01 G. Gentile , C. Tydtgat , M. Baes , G. De Geyter , M. Koleva , G. W. Angus , W. J. G. de Blok , W. Saftly , S. Viaene

It was recently proposed that the globular cluster system of the very low surface-brightness galaxy NGC1052-DF2 is dynamically very cold, leading to the conclusion that this dwarf galaxy has little or no dark matter. Here, we show that a…

Astrophysics of Galaxies · Physics 2018-05-23 Nicolas F. Martin , Michelle L. M. Collins , Nicolas Longeard , Erik Tollerud

The Milky Way has at least twenty-three known satellite galaxies that shine with luminosities ranging from about a thousand to a billion times that of the Sun. Half of these galaxies were discovered in the past few years in the Sloan…

We report here the discovery of an apparent excess of 2MASS M giant candidates with dereddened 0.85 < J-K_S < 1.2 spanning a considerably large area of the celestial sphere between, at least, $100\degr < l < 150\degr$ and $-20\degr > b >…

A wealth of tiny galaxies populates the surroundings of the Milky Way. Some of these objects might have their origin as former satellites of the Large Magellanic Cloud. Examples of the importance of understanding how many systems are…

Astrophysics of Galaxies · Physics 2019-03-20 T. K. Fritz , R. Carrera , G. Battaglia , S. Taibi

We present new chemo--kinematics of the Hercules dwarf galaxy based on Keck II-- DEIMOS spectroscopy. Our 21 confirmed members have a systemic velocity of $v_{\mathrm{Herc}}=46.4\pm1.3$ kms$^{-1}$ and a velocity dispersion…

We present Keck/DEIMOS spectroscopy of stars in the recently discovered Milky Way satellites Hydra II, Pisces II, and Laevens 1. We measured a velocity dispersion of 5.4 (+3.6 -2.4) km/s for Pisces II, but we did not resolve the velocity…

Astrophysics of Galaxies · Physics 2015-09-01 Evan N. Kirby , Joshua D. Simon , Judith G. Cohen

We present the discovery of Aquarius III, an ultra-faint Milky Way satellite galaxy identified in the second data release of the DECam Local Volume Exploration (DELVE) survey. Based on deeper follow-up imaging with DECam, we find that…

The velocity dispersion of the ultra diffuse galaxy NGC1052-DF2 was found to be $\sigma_{\rm gc}=7.8^{+5.2}_{-2.2} \ \mathrm{kms^{-1}}$, much lower than expected from the stellar mass -- halo mass relation and nearly identical to the…

Astrophysics of Galaxies · Physics 2019-04-03 Shany Danieli , Pieter van Dokkum , Charlie Conroy , Roberto Abraham , Aaron J. Romanowsky

We introduce a comprehensive analysis of multi-epoch stellar line-of-sight velocities to determine the intrinsic velocity dispersion of the ultrafaint satellites of the Milky Way. Our method includes a simultaneous Bayesian analysis of both…

Astrophysics of Galaxies · Physics 2011-08-17 Gregory D. Martinez , Quinn E. Minor , James Bullock , Manoj Kaplinghat , Joshua D. Simon , Marla Geha

Triangulum-II, a newly discovered dwarf spheroidal galaxy, is a strong candidate for the indirect search of dark matter through the detection of $\gamma$-ray emission that could originate from the pair- annihilation of weakly interacting…

High Energy Astrophysical Phenomena · Physics 2018-04-10 Sayan Biswas , Pooja Bhattacharjee , Pratik Majumdar , Subinoy Das , Mousumi Das , Parthasarathi Joarder

We present Keck/DEIMOS spectroscopy and CFHT/MegaCam photometry for the Milky Way globular cluster Palomar 13. We triple the number of spectroscopically confirmed members, including many repeat velocity measurements. Palomar 13 is the only…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 J. D. Bradford , M. Geha , R. Munoz , F. A. Santana , J. D. Simon , P. Cote , P. B. Stetson , E. Kirby , S. G. Djorgovski

Over the past five years, searches in Sloan Digital Sky Survey data have more than doubled the number of known dwarf satellite galaxies of the Milky Way, and have revealed a population of ultra-faint galaxies with luminosities smaller than…

Cosmology and Nongalactic Astrophysics · Physics 2009-02-23 James S. Bullock , Manoj Kaplinghat , Andrew Fruchter , Marla Geha , Joshua D. Simon , Louis E. Strigari , Beth Willman

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

Photometry alone is not sufficient to unambiguously distinguish between ultra-faint star clusters and dwarf galaxies because of their overlap in morphological properties. Here we report on VLT/GIRAFFE spectra of candidate member stars in…

Precise radial velocity measurements from HIRES on the Keck I telescope are presented for 40 stars in the outer halo globular cluster NGC 2419. These data are used to probe the cluster's stellar mass function and search for the presence of…

Astrophysics of Galaxies · Physics 2015-05-13 H. Baumgardt , P. Cote , M. Hilker , M. Rejkuba , S. Mieske , S. G. Djorgovski , P. Stetson

We present a detailed study of the faint Milky Way satellite Draco II (Dra II) from deep CFHT/MegaCam broadband $g$ and $i$ photometry and narrow-band metallicity-sensitive CaHK observations, along with follow-up Keck II/DEIMOS multi-object…