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Related papers: Estimation of the Vertical Disk Scale Height Using…

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We have obtained new estimates of the Sun's distance from the symmetry plane Zo and the vertical disk scale height h using currently available data on stellar OB associations, Wolf-Rayet stars, HII regions, and Cepheids. Based on individual…

Astrophysics of Galaxies · Physics 2016-07-04 V. V. Bobylev , A. T. Bajkova

Up-to-date data on 2214 classical Cepheids have been used. The model of an exponential matter density distribution in the Galactic thin disk has been applied. New estimates of the radial disk scale length $h_R,$ the distance of the Sun from…

Astrophysics of Galaxies · Physics 2021-10-22 V. V. Bobylev , A. T. Bajkova

The vertical structure of galactic disks is an important probe of disk assembly history. We investigate a sample of 79 local disk galaxies within 50 Mpc using data from the DESI Legacy Imaging Surveys. Vertical luminosity profiles as a…

Astrophysics of Galaxies · Physics 2026-04-14 Nan Chen , Jianhui Lian , Yuze Zhao

Data on HII regions, molecular clouds, and methanol masers have been used to estimate the Sun's distance from the symmetry plane zo and the vertical disk scale height h. Kinematic distance estimates are available for all objects in these…

Astrophysics of Galaxies · Physics 2016-01-26 V. V. Bobylev , A. T. Bajkova

Here we discuss impacts of distance determinations on the Galactic disk traced by relatively young objects. The Galactic disk, about 40 kpc in diameter, is a cross-road of studies on the methods of measuring distances, interstellar…

Solar and Stellar Astrophysics · Physics 2018-05-16 Noriyuki Matsunaga , Giuseppe Bono , Xiaodian Chen , Richard de Grijs , Laura Inno , Shogo Nishiyama

Disk galaxies viewed as thin planar structures resulting from the conservation of angular momentum of an initially rotating pre-galactic cloud allow merely a first-order model of galaxy formation. Still, the presence of vertically extended…

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…

Galactic disk warp has been widely characterized by stellar distributions and stellar kinematics but has not been traced by stellar chemistry. Here, we use a sample with over 170,000 red clump (RC) stars selected from LAMOST and APOGEE…

Astrophysics of Galaxies · Physics 2024-12-18 Weixiang Sun , Han Shen , Biwei Jiang , Xiaowei Liu

To investigate the formation and evolution of vertical structures in disk galaxies, we measure global $\operatorname{sech}^2$ scale heights, averaging thin and thick components when present, for 2631 edge-on disk galaxies with $M_*>10^{10}…

This paper is an initial stage of consideration of the general problem of joint modeling of the vertical structure of a Galactic flat subsystem and the average surface of the disk of the Galaxy, taking into account the natural and…

Astrophysics of Galaxies · Physics 2023-01-11 Igor' I. Nikiforov , Vadim A. Usik , Angelina V. Veselova

The vertical metallicity gradient of the Galactic disk offers valuable insights into the disk's formation and chemical evolution over time. We utilized the LAMOST-LRS young stellar sample to investigate this gradient and found that it…

Astrophysics of Galaxies · Physics 2025-04-03 Gaohuan Long , Haibo Yuan , Shuai Xu , Chun Wang , Ruoyi Zhang , Bowen Huang

We estimated the galactic model parameters for a set of 20 intermediate-latitude fields with galactic longitudes 0<l<100 and 160<l<240, included in the currently available Data Release 6 (DR6) of SDSS, to explore their possible variation…

Astrophysics of Galaxies · Physics 2015-05-13 E. Yaz , S. Karaali

We present full modeling of tangent point emission of HI as seen in the 21 cm transition in the inner Galaxy ($R \simeq 3-8 \kpc$). The model used takes into account emission from a large path length along the line of sight, corresponding…

Astrophysics · Physics 2011-03-28 Sangeeta Malhotra

We estimated the Galactic model parameters for a set of 36 high-latitude fields included in the currently available Data Release 5 (DR 5) of the Sloan Digital Sky Survey ({\em SDSS}), to explore their possible variation with the Galactic…

Astrophysics · Physics 2009-11-13 S. Bilir , A. Cabrera-Lavers , S. Karaali , S. Ak , E. Yaz , López-Corredoira

We propose a new method to measure and map the gas scale height of nearby disk galaxies. This method is applied successfully to the Australia Telescope Compact Array interferometric HI survey of the Large Magellanic Cloud (LMC); it could…

Astrophysics · Physics 2009-11-06 Paolo Padoan , Sungeun Kim , Alyssa Goodman , Lister Staveley--Smith

In decomposing the HI rotation curves of disc galaxies, it is necessary to break a degeneracy between the gravitational fields of the disc and the dark halo by estimating the disc surface density. This is done by combining measurements of…

Astrophysics of Galaxies · Physics 2016-01-13 S. Aniyan , K. C. Freeman , O. E. Gerhard , M. Arnaboldi , C. Flynn

We investigate the dynamical effects of a molecular cloud complex with a mass of about 10**7 M_sun and a size of a few 100 pc on the vertical distribution of stars and atomic hydrogen gas in a spiral galactic disc. Such massive complexes…

Astrophysics · Physics 2009-11-07 Chanda J. Jog , Chaitra A. Narayan

We report a three year, 18 epoch, VLBI monitoring study of H2O masers in the sub-parsec, warped, accretion disk within the NGC4258 AGN. Our immediate goals are to trace the geometry of the underlying disk, track rotation via measurement of…

Astrophysics · Physics 2011-02-11 A. L. Argon , L. J. Greenhill , M. J. Reid , J. M. Moran , E. M. L. Humphreys

We examine the vertical structure and equilibrium of the molecular gas layer in the galactic disk, measuring its scale height and velocity dispersion as a function of Galactic radius by modeling the CO emission at the tangent points. The…

Astrophysics · Physics 2009-10-22 Sangeeta Malhotra

We present an updated three dimensional map of the Milky Way based on a sample of 2431 classical Cepheid variable stars, supplemented with about 200 newly detected classical Cepheids from the OGLE survey. The new objects were discovered as…

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