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We measure the circular velocity curve $v_{\rm c}(R)$ of the Milky Way with the highest precision to date across Galactocentric distances of $5\leq R \leq 25$ kpc. Our analysis draws on the $6$-dimensional phase-space coordinates of…

Astrophysics of Galaxies · Physics 2019-03-06 Anna-Christina Eilers , David W. Hogg , Hans-Walter Rix , Melissa Ness

A spectral analysis of the vertical positions and velocities of 374 open star clusters (OSCs) was carried out. We took these OSCs from the Hunt, Reffert catalog; they have an average age of about 10 million years, and are located on the…

Astrophysics of Galaxies · Physics 2024-01-05 Vadim V. Bobylev , Anisa T. Bajkova

To construct the rotation curve of the Galaxy, classical Cepheids with proper motions, parallaxes and line-of-sight velocities from the Gaia DR2 Catalog are used in large part. The working sample formed from literature data contains about…

Astrophysics of Galaxies · Physics 2021-03-02 V. V. Bobylev , A. T. Bajkova , A. S. Rastorguev , M. V. Zabolotskikh

The 2MFGC catalog we have used contains 18020 galaxies selected from the extended objects in the 2MASS infrared sky survey as having apparent ratios of the axes b/a<0.3. Most of them are spiral galaxies of later morphological types whose…

Astrophysics · Physics 2008-11-26 I. D. Karachentsev , Yu. N. Kudrya , V. E. Karachentseva , S. N. Mitronova

We consider the time derivatives of the period $P$ of pulsars at the Galactic Center due to variations in their orbital Doppler shifts. We show that in conjunction with a measurement of a pulsar's proper motion and its projected separation…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 Pierre Christian , Abraham Loeb

To estimate the parameters of the Galactic spiral structure - namely, the pitch angle i and the number of spiral arms,- data on Galactic masers with known trigonometric parallaxes were used. We applied the well-known method based on…

Astrophysics of Galaxies · Physics 2015-06-17 Vadim V. Bobylev , Anisa T. Bajkova

We report measurements of centripetal accelerations of maser spectral components of NGC 4258 for 51 epochs spanning 1994 to 2004. This is the second paper of a series, in which the goal is determination of a new geometric maser distance to…

Astrophysics · Physics 2009-11-13 E. M. L. Humphreys , M. J. Reid , L. J. Greenhill , J. M. Moran , A. L. Argon

Through high-precision radio timing observations, we show that five recycled pulsars in the direction of the Galactic Centre (GC) have anomalous spin period time derivative ($\dot P$) measurements -- PSRs J1748$-$3009, J1753$-$2819,…

An accurate knowledge of the dark matter distribution in the Milky Way is of crucial importance for galaxy formation studies and current searches for particle dark matter. In this paper we set new dynamical constraints on the Galactic dark…

Astrophysics of Galaxies · Physics 2015-12-03 Miguel Pato , Fabio Iocco , Gianfranco Bertone

The Galaxy's stellar halo seems to be a tangle of disrupted systems that have been tidally stretched out into streams. Each stream approximately delineates an orbit in the Galactic force-field. In the first paper in this series we showed…

Astrophysics of Galaxies · Physics 2009-10-24 Andy Eyre , James Binney

In recent years, radio interferometric observations have achieved high accuracy in determining the absolute values of trigonometric parallaxes and proper motions of maser radiation sources and radio stars. The error in determining the…

Astrophysics of Galaxies · Physics 2022-12-09 V. V. Bobylev , A. T. Bajkova

We present a revised and expanded catalog of satellite galaxies of a set of isolated spiral galaxies similar in luminosity to the Milky Way. This sample of 115 satellites, 69 of which were discovered in our multifiber redshift survey, is…

Astrophysics · Physics 2009-09-25 Dennis Zaritsky , Rodney Smith , Carlos Frenk , Simon D. M. White

We report measurements of trigonometric parallax and proper motion for two 6.7 GHz methanol and two 22 GHz water masers located in the far portion of the Sagittarius spiral arm as part of the BeSSeL Survey. Distances for these sources are…

Astrophysics of Galaxies · Physics 2024-05-21 S. B. Bian , Y. W. Wu , Y. Xu , M. J. Reid , J. J. Li , B. Zhang , K. M. Menten , L. Moscadelli , A. Brunthaler

We present the results of determining the parameters of the spiral arms of the Galaxy using the stars Gaia DR3, whose absolute magnitude is $M_G$ < 4, and which allow tracing spiral arms at large distances from the Sun. As tracers of spiral…

Astrophysics of Galaxies · Physics 2023-08-29 S. I. Denyshchenko , P. N. Fedorov , V. S. Akhmetov , A. B. Velichko , A. M. Dmytrenko

The BeSSeL Survey is mapping the spiral structure of the Milky Way by measuring trigonometric parallaxes of hundreds of maser sources associated with high-mass star formation. While parallax techniques for water masers at high frequency (22…

Instrumentation and Methods for Astrophysics · Physics 2017-07-26 M. J. Reid , A. Brunthaler , K. M. Menten , A. Sanna , Y. Xu , J. J. Li , Y. Wu , B. Hu , X. W. Zheng , B. Zhang , K. Immer , K. Rygl , L. Moscadelli , N. Sakai , A. Bartkiewicz , Y. K. Choi

Here we report the detection, in Halpha emission, of a radial corrugation in the velocity field of the spiral galaxy NGC 5427. The central velocity of the Halpha line displays coherent, wavy-like variations in the vicinity of the spiral…

A wealth of new information about the structure of the maser disk in NGC 4258 has been obtained from a series of 18 VLBA observations spanning three years, as well as from 32 additional epochs of spectral monitoring data from 1994 to the…

Astrophysics · Physics 2009-11-13 Jim Moran , Liz Humphreys , Lincoln Greenhill , Mark Reid , Alice Argon

We analyse the three-dimensional structure and kinematics of two samples of young stars in the Galactic disc, containing respectively young giants ($\sim$17$\, $000 stars out to heliocentric distances of $\sim$7 kpc) and classical Cepheids…

Astrophysics of Galaxies · Physics 2025-07-16 E. Poggio , S. Khanna , R. Drimmel , E. Zari , E. D'Onghia , M. G. Lattanzi , P. A. Palicio , A. Recio-Blanco , L. Thulasidharan

Future microwave sky surveys will have the sensitivity to detect the kinematic Sunyaev-Zeldovich signal from moving galaxy clusters, thus providing a direct measurement of their line-of-sight peculiar velocity. We show that cluster peculiar…

Astrophysics · Physics 2009-11-11 Suman Bhattacharya , Arthur Kosowsky

We report trigonometric parallax and proper motion measurements of 6.7-GHz CH3OH and 22-GHz H2O masers in eight high-mass star-forming regions (HMSFRs) based on VLBA observations as part of the BeSSeL Survey. The distances of these HMSFRs…

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