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We use high-resolution H {\alpha} images of 130 planetary nebulae (PNe) to investigate whether there is a preferred orientation for PNe within the Galactic Bulge. The orientations of the full sample have an uniform distribution. However, at…

Solar and Stellar Astrophysics · Physics 2015-06-16 B. Rees , A. A. Zijlstra

We constructed a Hubble Space Telescope (HST) astro-photometric catalog of the central region of the Galactic globular cluster NGC 1261. This catalog, complemented with Gaia DR2 data sampling the external regions, has been used to estimate…

Solar and Stellar Astrophysics · Physics 2020-05-27 S. Raso , M. Libralato , A. Bellini , F. R. Ferraro , B. Lanzoni , M. Cadelano , C. Pallanca , E. Dalessandro , G. Piotto , J. Anderson , S. T. Sohn

We extend models of our Galaxy based on distribution functions (DFs) that are analytic functions of the action integrals to extended distribution functions (EDFs), which have an analytic dependence on metallicity as well. We use a simple,…

Astrophysics of Galaxies · Physics 2015-06-03 Jason L. Sanders , James Binney

The Galactic Center region, including the nuclear disk, has until recently been largely avoided in chemical census studies because of extreme extinction and stellar crowding. Making use of the latest APOGEE data release (DR16), we are able…

We perform analysis of the three-dimensional kinematics of Milky Way disk stars in mono-age populations. We focus on stars between Galactocentric distances of $R=6$ and 14 \,kpc, selected from the combined LAMOST DR4 red clump giant stars…

We report a kinematic signature associated with the observed asymmetry in the distribution of thick disk/inner halo stars interior to the Solar circle described in Paper I. In that paper we found a statistically significant excess (20% to…

Astrophysics · Physics 2015-06-24 Jeniffer E. Parker , Roberta M. Humphreys , Timothy C. Beers

The rotation of horizontal branch stars places important constraints on angular momentum evolution in evolved stars and therefore rotational mixing on the giant branch. Prompted by new observations of rotation rates of horizontal branch…

Astrophysics · Physics 2009-10-31 A. Sills , M. Pinsonneault

NaCl is a diatomic molecule with a large dipole moment, which allows for its detection even at relatively small abundances. It has been detected towards several evolved stars, among which is the AGB star IK Tau, around which it is…

Solar and Stellar Astrophysics · Physics 2023-10-11 A. Coenegrachts , T. Danilovich , F. De Ceuster , L. Decin

Context: Observations of asymptotic giant branch (AGB) stars with increasing spatial resolution reveal new layers of complexity of atmospheric processes on a variety of scales. Aim: To analyze the physical mechanisms that cause asymmetries…

Solar and Stellar Astrophysics · Physics 2017-04-19 Bernd Freytag , Sofie Liljegren , Susanne Höfner

Major-axis long-slit stellar kinematics was obtained for 30 edge-on spiral galaxies, 24 with a boxy/peanut-shaped (B/PS) bulge. B/PS bulges are present in >45% of highly inclined systems and much work suggests that they are the edge-on…

Astrophysics · Physics 2009-11-10 A. Chung , M. Bureau

We present the stellar kinematics across the Galactic bulge and into the disk at positive longitudes from the SDSS-III APOGEE spectroscopic survey of the Milky Way. APOGEE includes extensive coverage of the stellar populations of the bulge…

We build a stellar-dynamical model of the Milky Way barred bulge and disk, using a newly implemented adaptive particle method. The underlying mass model has been previously shown to match the Galactic near-infrared surface brightness as…

Astrophysics · Physics 2009-11-10 Nicolai Bissantz , Victor P. Debattista , Ortwin Gerhard

Non-axisymmetric components, such as spirals and central bars, play a major role in shaping galactic discs. An important aspect of the disc secular evolution driven by these perturbers is the radial migration of stars. It has been suggested…

Astrophysics of Galaxies · Physics 2015-06-05 I. Minchev , B. Famaey , A. C. Quillen , W. Dehnen , M. Martig , A. Siebert

We present adaptive optics assisted integral field spectroscopy of 34 star-forming galaxies at $z$ = 0.8-3.3 selected from the HiZELS narrow-band survey. We measure the kinematics of the ionised interstellar medium on $\sim$1 kpc scales,…

The dynamical evolution of globular clusters is theoretically described by a series of well known events typical of N-body systems. Still, the identification of observational signatures able to empirically describe the stage of dynamical…

Solar and Stellar Astrophysics · Physics 2023-02-01 Giacomo Beccari , Mario Cadelano , Emanuele Dalessandro

We have traced the spatial distributions of intermediate-age and old stars in nine dwarf galaxies in the distant parts of the Local Group, using multi-epoch 3.6 and 4.5 micron data from the DUST in Nearby Galaxies with Spitzer (DUSTiNGS)…

(Abridged) Infrared high-resolution imaging and interferometry have shown that the dust distribution is frequently elongated along the polar direction of an AGN. To explain these findings, we developed a model scenario for the inner ~30 pc…

Astrophysics of Galaxies · Physics 2018-08-15 B. Vollmer , M. Schartmann , L. Burtscher , F. Marin , S. Hoenig , R. Davies , R. Goosmann

We carry out a detailed orbit analysis of gravitational potentials selected at different times from an evolving self-consistent model galaxy consisting of a two-component disk (stars+gas) and a live halo. The results are compared with a…

Astrophysics · Physics 2009-10-30 I. Berentzen , C. H. Heller , I. Shlosman , K. J. Fricke

We present semi-analytical models and simplified $N$-body simulations with $10^4$ and $10^5$ particles aimed at probing the role of dynamical friction (DF) in determining the radial distribution of Blue Straggler Stars (BSSs) in globular…

Astrophysics of Galaxies · Physics 2015-01-16 P. Miocchi , M. Pasquato , B. Lanzoni , F. R. Ferraro , E. Dalessandro , E. Vesperini , E. Alessandrini , Y. W. Lee

Within a half-parsec from the Galactic center (GC), there is a population of coeval young stars which appear to reside in a coherent disk. Surrounding this dynamically-cool stellar system, there is a population of stars with a similar age…

Astrophysics · Physics 2011-05-12 Qingjuan Yu , Youjun Lu , D. N. C. Lin