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With abundances and 2{\sigma} upper limits of fluorine (F) in seven metal-poor field giants, nucleosynthesis of stellar F at low metallicity is discussed. The measurements are derived from the HF(1-0) R9 line at 23358{\AA} using…

Astrophysics of Galaxies · Physics 2013-02-19 H. N. Li , H. -G. Ludwig , E. Caffau , N. Christlieb , G. Zhao

Hypervelocity stars (HVSs) travel from the Galactic Centre across the dark matter halo of the Milky Way, where they are observed with velocities in excess of the Galactic escape speed. Because of their quasi-radial trajectories, they…

Astrophysics of Galaxies · Physics 2019-06-14 O. Contigiani , E. M. Rossi , T. Marchetti

We present first results from a spectroscopic survey of 2000 F/G stars 0.5--5kpc from the Galactic plane, obtained with the 2dF facility on the AAT. These data show the mean rotation velocity of the thick disk about the Galactic center a…

Astrophysics · Physics 2009-11-07 Gerard Gilmore , Rosemary F. G. Wyse , John E. Norris

We use numerical simulations to examine the substructure within galactic and cluster mass halos that form within a hierarchical universe. Clusters are easily reproduced with a steep mass spectrum of thousands of substructure clumps that…

We obtained ESI/Keck rotation curves of 10 MgII absorption selected galaxies (0.3 < z < 1.0) for which we have WFPC-2/HST images and high resolution HIRES/Keck and UVES/VLT quasar spectra of the MgII absorption profiles. We perform a…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 G. G. Kacprzak , C. W. Churchill , D. Ceverino , C. C. Steidel , A. Klypin , M. T. Murphy

The sensitivity of direct detection experiments depends on the phase-space distribution of dark matter near the Sun, which can be modeled theoretically using cosmological hydrodynamical simulations of Milky Way-like galaxies. However,…

High Energy Physics - Phenomenology · Physics 2026-04-08 Dylan Folsom , Carlos Blanco , Mariangela Lisanti , Lina Necib , Mark Vogelsberger , Lars Hernquist

Isotropic diffusion models for Galactic cosmic ray transport put tight constraints on the maximum convection velocity in the halo. For a half halo height of 4 kpc the maximum convection speed is limited to 40 km/s in the halo, since…

Astrophysics of Galaxies · Physics 2009-10-13 Iris Gebauer , Wim de Boer

We study massive disk galaxies (total stellar mass$>=10^{11}$ $\mathrm{M_{\odot}}$) from IllustrisTNG50 simulation, and perform 2-D structural decomposition of the galaxies using their idealised, synthetic SDSS images for z=0. We find an…

Astrophysics of Galaxies · Physics 2026-02-11 Suchira Sarkar , Kanak Saha

We analyze the Illustris-1 hydrodynamical cosmological simulation to explore the stellar velocity dispersion of quiescent galaxies as an observational probe of dark matter halo velocity dispersion and mass. Stellar velocity dispersion is…

Astrophysics of Galaxies · Physics 2018-06-13 H. Jabran Zahid , Jubee Sohn , Margaret J. Geller

We report sub-pc-scale observations of the 321-GHz H$_2$O emission line in the radio galaxy NGC 1052. The H$_2$O line emitter size is constrained in $< 0.6$ milliarcsec distributed on the continuum core component. The brightness temperature…

Recently, we determined a lower bound for the Milky Way mass in a point mass approximation. This result was obtained for most general spherically symmetric phase-space distribution functions consistent with a measured radial velocity…

Astrophysics of Galaxies · Physics 2016-11-04 Szymon Sikora , Łukasz Bratek , Joanna Jałocha , Marek Kutschera

Dwarf galaxies have a wide variety of structures, such as dark matter (DM) distribution, stellar-to-halo mass ratio, and stellar density. Recent high-resolution simulations have shown a variety of stellar-to-halo mass ratios for dwarf…

Astrophysics of Galaxies · Physics 2026-01-21 Katsuhiro Kaneko , Takayuki R. Saitoh , Yutaka Hirai , Michiko S. Fujii

We report the small-scale spatial variation in cool ($T\sim 10^4 K$) Mg II absorption detected in the circumgalactic medium (CGM) of a star-forming galaxy at $z\approx 0.8$. The CGM of this galaxy is probed by a spatially extended bright…

As the Milky Way and its satellite system become more entrenched in near field cosmology efforts, the need for an accurate mass estimate of the Milky Way's dark matter halo is increasingly critical. With the second and early third data…

Our GMRT HI observations of the ultra diffuse galaxy (UDG) UGC 2162, projected $\sim$ 300 kpc from the centre of the M77 group, reveal it to a have an extended HI disk (R$_{HI}$/R$_{25}$ $\sim$ 3.3) with a moderate rotational velocity…

Astrophysics of Galaxies · Physics 2019-07-31 Chandreyee Sengupta , T. C. Scott , Aeree Chung , O. Ivy Wong

Recent advancements in the imaging of low-surface-brightness objects revealed numerous ultra-diffuse galaxies in the local Universe. These peculiar objects are unusually extended and faint: their effective radii are comparable to the Milky…

Astrophysics of Galaxies · Physics 2019-07-10 Orsolya E. Kovacs , Akos Bogdan , Rebecca E. A. Canning

Using detailed mock galaxy redshift surveys we investigate to what extent the kinematics of large samples of satellites galaxies extracted from flux-limited surveys can be used to constrain halo masses. Previous host-satellite selection…

Astrophysics · Physics 2009-11-10 Frank C. van den Bosch , Peder Norberg , H. J. Mo , Xiaohu Yang

Present-day galaxies are surrounded by cool and enriched halo gas extending to hundreds of kiloparsecs. This halo gas is thought to be the dominant reservoir of material available to fuel future star formation, but direct constraints on its…

The spatial distribution of satellite galaxies around host galaxies can illuminate the relationship between satellites and dark matter subhalos and aid in developing and testing galaxy formation models. Previous efforts to constrain the…

Astrophysics · Physics 2009-06-23 Jacqueline Chen

[Abridged] We analyse the dark matter (DM) halo properties of 127 0.3<z<1.5 star-forming galaxies (SFGs) down to low stellar masses (8<log(Mstar/Msun)<11), using data from the MUSE Hubble Ultra Deep Field Survey and photometry from HST and…

Astrophysics of Galaxies · Physics 2026-04-01 B. I. Ciocan , N. F. Bouché , J. Fensch , W. Mercier , D. Krajnović , J. Richard , T. Contini , A. Jeanneau