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Since 1999, a radial velocity survey of 179 red giant stars is ongoing at Lick Observatory with a one month cadence. At present ~20-100 measurements have been collected per star with an accuracy of 5 to 8 m/s. Of the stars monitored, 145…

Astrophysics · Physics 2008-11-26 S. Hekker , I. A. G. Snellen , C. Aerts , A. Quirrenbach , S. Reffert , D. S. Mitchell

We present a modification of the method for reconstructing the stellar velocity ellipsoid (SVE) in disc galaxies. Our version does not need any parametrization of the velocity dispersion profiles and uses only one assumption that the ratio…

Astrophysics of Galaxies · Physics 2017-02-27 A. A. Marchuk , N. Y. Sotnikova

We study the spatial distribution of satellite galaxies by assuming that they follow the dark matter distribution. This assumption is supported by semi-analytical studies based on high-resolution numerical simulations. We find that for a…

Astrophysics · Physics 2009-11-10 X. Kang , S. Mao , L. Gao , Y. P. Jing

Recently the commissioning APOGEE observations of the Galactic bulge reported that a significant fraction of stars ($\sim10%$) are in a cold ($\sigma_{\rm V} \approx 30$ km/s) high velocity peak (Galactocentric radial velocity $\approx 200$…

Astrophysics of Galaxies · Physics 2015-06-18 Zhao-Yu Li , Juntai Shen , R. Michael Rich , Andrea Kunder , Shude Mao

We investigate the distribution of central velocity dispersions for quiescent galaxies in the SDSS at $0.03 \leq z \leq 0.10$. To construct the field velocity dispersion function (VDF), we construct a velocity dispersion complete sample of…

Astrophysics of Galaxies · Physics 2017-08-23 Jubee Sohn , H. Jabran Zahid , Margaret J. Geller

We present a spectroscopic sample of 910 distant halo stars from the Hypervelocity Star survey from which we derive the velocity dispersion profile of the Milky Way halo. The sample is a mix of 74% evolved horizontal branch stars and 26%…

Astrophysics of Galaxies · Physics 2010-07-22 Warren R. Brown , Margaret J. Geller , Scott J. Kenyon , Antonaldo Diaferio

We attempt to recover the mean vertical velocity and vertical velocity dispersion as a function of the Galactic height for a sample drawn from a realistic Galaxy distribution function by following the method presented in Moni Bidin et al.…

Astrophysics of Galaxies · Physics 2014-06-16 Jason Sanders

We estimate the vertical gradient of rotational velocity for several spiral galaxies in the framework of a global thin-disc model, using the approximation of quasi-circular orbits. We obtain gradients having a broad range of values, in…

Astrophysics of Galaxies · Physics 2011-04-27 Joanna Jałocha , Łukasz Bratek , Marek Kutschera , Piotr Skindzier

We measure the distribution of velocity dispersions of groups of galaxies identified in the UZC catalog; we use the distribution to derive the group mass function. We introduce a new method which makes efficient use of the entire magnitude…

Astrophysics · Physics 2009-11-10 Armando Pisani , Massimo Ramella , Margaret J. Geller

We examine the relation between stellar mass and central stellar velocity dispersion-the M-sigma relation-for massive quiescent galaxies at z<0.7. We measure the local relation from the Sloan Digital Sky Survey and the intermediate redshift…

Astrophysics of Galaxies · Physics 2016-12-14 H. Jabran Zahid , Margaret Geller , Daniel Fabricant , Ho Seong Hwang

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

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is a major facility to carry out spectroscopic surveys for cosmology and galaxy evolution studies. The seventh data release of the LAMOST ExtraGAlactic Survey (LEGAS) is…

Astrophysics of Galaxies · Physics 2020-11-24 Nicola R. Napolitano , Giuseppe D'Ago , Crescenzo Tortora , Gang Zhao , A-Li Luo , Baitian Tang , Wei Zhang , Yong Zhang , Rui Li

Although thick disk is a structure prevalent in local disk galaxies and also present in our home Galaxy, its formation and evolution is still unclear. Whether the thick disk is born thick and/or gradually heated to be thick after formation…

Astrophysics of Galaxies · Physics 2023-12-13 Jianhui Lian , Li Luo

As part of a radial velocity survey of low Galactic latitude structures that we undertook with the 2dF spectrograph on the AAT, we present the radial velocities of more than 1500 Red Giant Branch and Red Clump stars towards the centre of…

Astrophysics · Physics 2009-11-10 N. F. Martin , R. A. Ibata , B. C. Conn , G. F. Lewis , M. Bellazzini , M. J. Irwin

Understanding the history and the evolution of the Milky Way disc is one of the main goals of modern astrophysics. We study the velocity dispersion behaviour of Galactic disc stars as a function of the [Mg/Fe] ratio, which can be used as a…

We present metallicities and their variations with different parameters for 36 high-latitude fields covering Galactic longitudes 0<l<360. The metallicities for relatively short vertical distances (z<2.5 kpc) show systematic fluctuations…

Astrophysics · Physics 2008-11-26 S. Ak , S. Bilir , S. Karaali , R. Buser , A. Cabrera-Lavers

The structure of a sample of high-redshift (z=2), rotating galaxies with high star formation rates and turbulent gas velocities of sigma=40-80 km/s is investigated. Fitting the observed disk rotational velocities and radii with a Mo, Mao,…

We present some new results from an ongoing investigation of the anisotropy of the two--point correlation function for optically selected galaxies. We have estimated xi(r_p,pi) from the Perseus-Pisces redshift survey, which is now virtually…

Astrophysics · Physics 2007-05-23 L. Guzzo , K. B. Fisher , M. S. Strauss , R. Giovanelli , M. P. Haynes

We use the Sloan Digital Sky Survey Data Release 12, which is the largest available white dwarf catalog to date, to study the evolution of the kinematical properties of the population of white dwarfs in the Galactic disc. We derive masses,…

We report measurements of parallax and proper motion for four 22 GHz water maser sources as part of VERA Outer Rotation Curve project. All sources show Galactic latitudes of $>$ 2$^{\circ}$ and Galactocentric distances of $>$ 11 kpc at the…

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