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We develop a model for regulation of galactic star formation rates Sigma_SFR in disk galaxies, in which ISM heating by stellar UV plays a key role. By requiring simultaneous thermal and (vertical) dynamical equilibrium in the diffuse gas,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Eve C. Ostriker , Christopher F. McKee , Adam K. Leroy

Binary stellar systems form a large fraction of the Galaxy's stars. They are useful as laboratories for studying the physical processes taking place within stars, and must be correctly taken into account when observations of stars are used…

The 3D velocities of M31 and M33 are important for understanding the evolution and cosmological context of the Local Group. Their most massive stars are detected by Gaia, and we use Data Release 2 (DR2) to determine the galaxy proper…

We apply the vertical Jeans equation to the kinematics of Milky Way stars in the solar neighbourhood to measure the local dark matter density. More than 90,000 G- and K-type dwarf stars are selected from the cross-matched sample of LAMOST…

Astrophysics of Galaxies · Physics 2020-06-10 Rui Guo , Chao Liu , Shude Mao , Xiang-Xiang Xue , R. J. Long , Lan Zhang

Our goal is to recover the Galactic Halo spatial density by means of field stars. To this aim, we apply a new technique to the Capodimonte Deep Field (OACDF, Alcala' et al. 2004), as a pilot study in view of the VLT Survey Telescope (VST)…

Astrophysics · Physics 2009-11-11 M. Cignoni , V. Ripepi , M. Marconi , J. M. Alcala' , M. Capaccioli , M. Pannella , R. Silvotti

This paper introduces new phase-space models of dwarf spheroidal galaxies (dSphs). The stellar component has an isotropic, lowered isothermal (or King) distribution function. A physical basis for the isotropization of stellar velocities is…

Astrophysics of Galaxies · Physics 2015-05-19 N. C. Amorisco , N. W. Evans

To constrain the Galactic gravitational potential near the Sun ($\sim$1.5 kpc), we derive and model the spatial and velocity distribution for a sample of 9000 K-dwarfs that have spectra from SDSS/SEGUE, which yield radial velocities and…

Astrophysics of Galaxies · Physics 2015-06-11 Lan Zhang , Hans-Walter Rix , Glenn van de Ven , Jo Bovy , Chao Liu , Gang Zhao

AIMS. We calculate the stellar density using star counts obtained from Gaia DR2 up to a Galactocentric distance R=20 kpc with a deconvolution technique for the parallax errors. Then we analyse the density in order to study the structure of…

Astrophysics of Galaxies · Physics 2020-05-27 Z. Chrobakova , R. Nagy , M. Lopez-Corredoira

The vertical density distribution of stars in a galactic disc is traditionally obtained by assuming an isothermal vertical velocity dispersion of stars. Recent observations from SDSS, LAMOST, RAVE, Gaia etc show that this dispersion…

Astrophysics of Galaxies · Physics 2020-12-04 Suchira Sarkar , Chanda J. Jog

In G dwarfs, the surface distribution, coverage and lifetimes of starspots deviate from solar-like patterns as the rotation rate increases. We set up a numerical platform which includes the large-scale rotational and surface flow effects,…

Solar and Stellar Astrophysics · Physics 2018-12-24 Emre Işık , Sami K. Solanki , Natalie A. Krivova , Alexander I. Shapiro

Diffuse interstellar bands (DIBs) are absorption features seen in optical and infrared spectra of stars that are probably caused by large and complex molecules in the ISM. Here we investigate the Galactic distribution and properties of two…

Thanks to Gaia and large-scale spectroscopic follow-up surveys (4MOST, DESI, WEAVE, SDSS-V), it is now possible to build representative and minimally biased samples of the local white dwarf population. Here we analyse several volume-limited…

Solar and Stellar Astrophysics · Physics 2026-04-08 Emily K. Roberts , Pier-Emmanuel Tremblay , Antoine Bédard

We present a wavelet-based algorithm to identify dwarf galaxies in the Milky Way in ${\it Gaia}$ DR2 data. Our algorithm detects overdensities in 4D position--proper motion space, making it the first search to explicitly use velocity…

Astrophysics of Galaxies · Physics 2021-07-15 Elise Darragh-Ford , Ethan O. Nadler , Sean McLaughlin , Risa H. Wechsler

We extend models of our Galaxy based on distribution functions (DFs) that are analytic functions of the action integrals to extended distribution functions (EDFs), which have an analytic dependence on metallicity as well. We use a simple,…

Astrophysics of Galaxies · Physics 2015-06-03 Jason L. Sanders , James Binney

This work presents the results of a kinematic analysis of the Galaxy that uses a new model as applied to the newest available Gaia data. We carry out the Taylor decomposition of the velocity field up to second order for 18 million high…

Astrophysics of Galaxies · Physics 2024-03-29 V. S. Akhmetov , B. Bucciarelli , M. Crosta , M. G. Lattanzi , A. Spagna , P. Re Fiorentin , E. Yu. Bannikova

Analysing stellar parameters and abundances from nearly one million Gaia Data Release 3 (DR3) Radial Velocity Spectrometer (RVS) spectra poses challenges due to the limited spectral coverage (restricted to the infrared Ca II triplet) and…

We develop a flexible set of action-based distribution functions (DFs) for stellar haloes. The DFs have five free parameters, controlling the inner and outer density slope, break radius, flattening and anisotropy respectively. The DFs…

Astrophysics of Galaxies · Physics 2015-09-30 A. A. Williams , N. W. Evans

We obtain a new determination of the metallicity distribution function (MDF) of stars within $\sim5$-$10$ kpc of the Sun, based on recently improved co-adds of $ugriz$ photometry for Stripe 82 from the Sloan Digital Sky Survey. Our new…

The local group dwarf spheroidal galaxies (LG dSphs) are among the most promising astrophysical targets for probing the small scale structure of dark matter (DM) subhalos. We describe a method for testing the correspondence between proposed…

Astrophysics of Galaxies · Physics 2020-12-09 Sasha Brownsberger , Lisa Randall

We present new scaling relations for the isotropic phase-space distribution functions (DFs) and energy distributions of simulated dark matter haloes. These relations are inspired by those for the singular isothermal sphere with density…

Astrophysics of Galaxies · Physics 2025-03-26 Axel Gross , Zhaozhou Li , Yong-Zhong Qian