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Related papers: Modelling the Galactic bar using OGLE-II Red Clump…

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We use the clump giants of the disk as standard candles calibrated from Hipparcos parallaxes in order to map their distribution with two new near-IR surveys of the Galactic plane: UKIDSS-GPS and VVV. We explore different selection cuts of…

Astrophysics of Galaxies · Physics 2011-05-17 D. Minniti , R. K. Saito , J. Alonso-García , P. W. Lucas , M. Hempel

We studied the fraction and properties of bars in a sample of about 3000 galaxies extracted from SDSS-DR5. This represents a volume limited sample with galaxies located between redshift 0.01<z<0.04, absolute magnitude Mr>-20, and…

Astrophysics · Physics 2008-02-04 J. Méndez-Abreu , J. A. L. Aguerri , E. M. Corsini

In this work, we derive systemic velocities and subsequently orbits for 8456 RR~Lyrae stars. We identify interlopers from other Milky Way (MW) structures, which amount to 22 percent of the total sample. Most interlopers are associated with…

Based on the most complete sample of Galactic open star clusters up to 1.8 kpc, we performed statistical analysis of the distribution of open cluster parameters in order to understand the Galactic structure. The geometrical characteristics…

Astrophysics of Galaxies · Physics 2017-07-31 Yogesh C. Joshi

We used red clump stars to measure the surface mass density of the Galactic disk in the solar neighbourhood. High resolution spectra of red clump stars towards the NGP have been obtained with the ELODIE spectrograph at OHP for Tycho-2…

Astrophysics · Physics 2009-11-11 O. Bienaymé , C. Soubiran , T. V. Mishenina , V. V. Kovtyukh , A. Siebert

We construct dynamical models of the Milky Way's Box/Peanut (B/P) bulge, using the recently measured 3D density of Red Clump Giants (RCGs) as well as kinematic data from the BRAVA survey. We match these data using the NMAGIC Made-to-Measure…

Astrophysics of Galaxies · Physics 2015-06-23 M. Portail , C. Wegg , O. Gerhard , I. Martinez-Valpuesta

We created new reddening maps and derived new extinction laws from visual to near-infrared passbands using improved RR~Lyrae period-absolute magnitude-metallicity relations, thus enabling distance estimates for individual bulge RR~Lyrae…

The Milky Way is widely considered to exhibit features of a rotational bar or quadrupole bar. In either case, the feature of the resonance of the Galactic bar should be present in the properties of the chemistry and kinematics, over a large…

Astrophysics of Galaxies · Physics 2024-04-09 Weixiang Sun , Han Shen , Biwei Jiang , Xiaowei Liu

We describe the motivation, field locations and stellar selection for the ARGOS spectroscopic survey of 28,000 stars in the bulge and inner disk of the Milky Way galaxy across latitudes of b = -5 deg to -10 deg. The primary goal of this…

Astrophysics of Galaxies · Physics 2012-12-10 K. Freeman , M. Ness , E. Wylie de Boer , E. Athanassoula , J. Bland Hawthorn , M. Asplund , G. Lewis , D. Yong , R. Lane , L. Kiss , R. Ibata

abridged: We use a complete sample of about 140,000 galaxies from the Sloan Digital Sky Survey (SDSS) to study the size distribution of galaxies and its dependence on their luminosity, stellar mass, and morphological type. The large SDSS…

We use Schwarzschild's orbit-superposition technique to construct self-consistent models of the Galactic bar. Using $\chi^2$ minimisation, we find that the best-fit Galactic bar model has a pattern speed $\Omega_{\rm p}=60 \rm{km s^{-1}…

Astrophysics of Galaxies · Physics 2015-06-11 Yougang Wang , Hongsheng Zhao , Shude Mao , R. M. Rich

We measure the red giant branch bump (RGBB) of the Galactic bulge, the most metal-rich RGBB ever detected. The RGBB luminosity functions peaks at the expected brightness, but its number density is very low relative to Galactic globular…

Astrophysics of Galaxies · Physics 2015-05-20 D. M. Nataf , A. Udalski , A. Gould , M. H. Pinsonneault

The photometry data base of the second phase of the OGLE microlensing experiment, OGLE-II, is a rich source of information about the kinematics and structure of the Galaxy. In this work we use the OGLE-II proper motion catalogue to identify…

Astrophysics · Physics 2009-11-13 Nicholas J. Rattenbury , Shude Mao

Using simulations of box/peanut- (B/P-) shaped bulges, we explore the nature of the X-shape of the Milky Way's bulge. An X-shape can be associated with a B/P-shaped bulge driven by a bar. By comparing in detail the simulations and the…

Astrophysics of Galaxies · Physics 2014-01-28 Esko Gardner , Victor P. Debattista , Annie C. Robin , Sergio Vásquez , Manuela Zoccali

The double red clumps (DRCs) are now dominantly believed to be the strong observational line of evidence of the so-called X-shaped Galactic bar structures. Recently, Lee et al. reported a subtle mean \ds\ difference between the DRCs and…

Astrophysics of Galaxies · Physics 2019-05-01 Jae-Woo Lee

Observational data indicate that the Milky Way is a barred spiral galaxy. Computation facilities and availability of data from Galactic surveys stimulate the appearance of models of the Galactic structure. More efforts to build dynamical…

Astrophysics of Galaxies · Physics 2018-07-18 Tatiana A. Michtchenko , Jacques R. D. Lépine , Douglas A. Barros , Ronaldo S. S. Vieira

Context: There is still some debate about the presence and the morphological properties of the long bar in the inner Galaxy. Aims: We investigate the morphological properties of the long Galactic bar using the VVV survey extending star…

We analyze the kinematics and spatial distribution of 15,599 fundamental-mode RR Lyrae (RRL) stars in the Milky Way bulge by combining OGLE-IV photometric data and Gaia DR2 proper motions. We show that the longitudinal proper motions and…

Astrophysics of Galaxies · Physics 2020-10-14 Hangci Du , Shude Mao , E. Athanassoula , Juntai Shen , Pawel Pietrukowicz

We present the metallicity results from the ARGOS spectroscopic survey of the Galactic bulge. Our aim is to understand the formation of the Galactic bulge: did it form via mergers, as expected from Lambda CDM theory, or from disk…

Astrophysics of Galaxies · Physics 2015-06-12 M. Ness , K. Freeman , E. Athanassoula , E. Wylie de Boer , J. Bland Hawthorn , M. Asplund , G. F. Lewis , D. Yong , R. R. Lane , L. L. Kiss

If the Galaxy is axisymmetric and in dynamical equilibrium, we expect negligible fluctuations in the residual line-of-sight velocity field. Recent results using the \apg{} survey find significant fluctuations in velocity for stars in the…

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