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Red clump stars are commonly used to map the reddening and morphology of the inner regions of the Milky Way. We use the new photometric catalogues of the VISTA Variables in the V\'ia L\'actea survey to achieve twice the spatial resolution…

Longitude-velocity (l-V) diagrams of H I and CO gas in the inner Milky Way have long been known to be inconsistent with circular motion in an axisymmetric potential. Several lines of evidence suggest that the Galaxy is barred, and gas flow…

Astrophysics · Physics 2008-11-26 Benjamin J. Weiner , J. A. Sellwood

This paper is the second part of Garzon et al. (1997: ApJ 491, L31) in which we presented an outline of the analysis of 60 spectra from a follow-up program to the Two Micron Galactic Survey (TMGS) project in the l=27 deg., b=0 deg. area. In…

We present relation of the mean I-band brightness of red clump stars on metallicity. Red clump stars were proposed to be a very attractive standard candle for distance determination. The calibration is based on 284 nearby red giant stars…

Astrophysics · Physics 2009-10-31 A. Udalski

I explore the hypothesis that many of the unusual aspects of the apparent stellar bar of the Large Magellanic Cloud are the result of viewing a triaxial stellar bulge that is embedded in a highly obscuring thin disk. Specifically, this…

Astrophysics · Physics 2009-11-10 Dennis Zaritsky

We have derived absolute proper motions of the entire Galactic bulge region from VIRAC and Gaia. We present these as both integrated on-sky maps and, after isolating standard candle red clump (RC) stars, as a function of distance using RC…

Astrophysics of Galaxies · Physics 2019-12-06 Jonathan P. Clarke , Christopher Wegg , Ortwin Gerhard , Leigh C. Smith , Phil W. Lucas , Shola M. Wylie

A small but significant radial gradient in the mean periods of LMC RR Lyrae variables is established from the OGLEIII survey data. This is interpreted as a metallicity gradient but other possibilities are discussed. Data on the ratio of…

Cosmology and Nongalactic Astrophysics · Physics 2010-08-16 Michael W Feast , Oyirwoth P Abedigamba , Patricia A Whitelock

We compute a microlensing map for the Galactic bar. The predicted event rate and event duration distribution are consistent with the $55$ events recently reported by the MACHO and OGLE collaborations. Most of the events are due to lensing…

Astrophysics · Physics 2015-06-24 HongSheng Zhao , R. M. Rich , D. N. Spergel

The LMC star BI 108 is photometrically variable with the unique light curve: Two strong periods are present in a strict 3:2 resonance, staying coherent over several observing seasons. A spectroscopic data collected at VLT/UVES reveals…

Solar and Stellar Astrophysics · Physics 2010-05-03 Zbigniew Kołaczkowski , Ronald Mennickent , Thomas Rivinius

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

Using a sample of nearly 140,000 red clump stars selected from the LAMOST and Gaia Galactic surveys, we have mapped mean vertical velocity $\overline{V_{z}}$ in the $X$-$Y$ plane for a large volume of the Galactic disk (6 $< R < 16$ kpc;…

Astrophysics of Galaxies · Physics 2020-09-30 X. -Y. Li , Y. Huang , B. -Q. Chen , H. -F. Wang , W. -X. Sun , H. -L. Guo , Q. -Z. Li , X. -W. Liu

Many barred galaxies, including the Large Magellanic Cloud (LMC), display strong lopsidedness and off-centre bars. The dynamical connection between bar-disc misalignments, internal mass asymmetries, and arm morphology is not yet fully…

Astrophysics of Galaxies · Physics 2026-05-20 P. Sánchez-Martín , M. López-Vilamajó , M. Romero-Gómez , J. J. Masdemont

We surveyed 291 MSX/2MASS infrared objects in the 7 x 2 deg area of the galactic center in the 43 GHz SiO J=1--0 v=1 and 2 maser lines, obtaining accurate radial velocities of 163 detected objects. The surveyed area is the region where the…

We present new reddening maps of the SMC and LMC based on the data of the third phase of the Optical Gravitational Lensing Experiment (OGLE III). We have used two different methods to derive optical reddening maps. We adopt a theoretical…

Astrophysics of Galaxies · Physics 2011-04-14 Raoul Haschke , Eva K. Grebel , Sonia Duffau

We use a combination of VJHK and Spitzer} [3.6], [5.8] and [8.0] photometry, to determine IR excesses in a sample of LMC and SMC O stars. This sample is ideal for determining excesses because: 1) the distances to the stars, and hence their…

Solar and Stellar Astrophysics · Physics 2010-10-19 D. Massa , A. Fullerton , D. Lennon , R. K. Prinja

We present MUSE integral field stellar and ionized velocity maps for a sample of 14 barred galaxies. Most of these objects exhibit "S"-shape iso-velocities in the bar region indicative of the presence of streaming motions in the velocity…

Recent data from the VVV survey have strengthened evidence for a structural change in the Galactic bulge inwards of |l|<=4 deg. Here we show with an N-body barred galaxy simulation that a boxy bulge formed through the bar and buckling…

Astrophysics of Galaxies · Physics 2015-06-03 Ortwin Gerhard , Inma Martinez-Valpuesta

We introduce a new approach to classify barred galaxies that utilizes the transverse-to-radial force ratio map (ratio map, hereafter) in a different manner from previous studies. When we display the ratio map in polar coordinates, barred…

Astrophysics of Galaxies · Physics 2020-08-26 Yun Hee Lee , Myeong-Gu Park , Hong Bae Ann , Taehyun Kim , Woo-Young Seo

Previous work has related the Galactic Bar to structure in the local stellar velocity distribution. Here we show that the Bar also influences the spatial gradients of the velocity vector via the Oort constants. By numerical integration of…

Astrophysics · Physics 2009-11-13 I. Minchev , J. Nordhaus , A. C. Quillen

Many strong simulated galactic bars experience buckling instability, which manifests itself as a vertical distortion out of the disk plane, and later dissipates. Using a simulation of an isolated Milky Way-like galaxy, I demonstrate that…

Astrophysics of Galaxies · Physics 2025-07-09 Ewa L. Lokas