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We investigate the detectability of starburst signatures in the nuclear spectrum of Seyfert 2 galaxies by constructing spectral models in the wavelength range 3500-4100A, combining the spectrum of a bulge population (of age ~10Gyr) with…

We present new optical long-slit data along 6 position angles of the bulge region of M31. We derive accurate stellar and gas kinematics reaching 5 arcmin from the center, where the disk light contribution is always less than 30%, and out to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 R. P. Saglia , M. Fabricius , R. Bender , M. Montalto , C. -H. Lee , A. Riffeser , S. Seitz , L. Morganti , O. Gerhard , U. Hopp

We have used photometric data on almost 91 000 fundamental-mode RR Lyrae stars (type RRab) detected by the OGLE survey to investigate properties of old populations in the Milky Way. Based on their metallicity distributions, we demonstrate…

New ages are computed for stars in the Solar Neighbourhood from the Edvardsson et al. (1993) data set. Distances derived from the Hipparcos parallaxes were adopted to obtain reliable ages (uncertainty less than 12%) for a subset of stars.…

Astrophysics · Physics 2007-05-23 Y. K. Ng , G. Bertelli , G. Carraro , L. Portinari

We have extracted PSF-fitted stellar photometry from near-ultraviolet, optical and near-infrared images, obtained with the Hubble Space Telescope, of the nearby (D ~ 5.5 Mpc) SBm galaxy NGC 1311. The ultraviolet and optical data reveal a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Paul B. Eskridge , Rogier A. Windhorst , Violet A. Mager , Rolf A. Jansen

Many disc galaxies in clusters have been found with bulges of similar age or younger than their surrounding discs, at odds with field galaxies of similar morphology and their expected inside-out formation. We use the EAGLE simulations to…

Astrophysics of Galaxies · Physics 2022-01-19 Joel Pfeffer , Kenji Bekki , Warrick J. Couch , Bärbel S. Koribalski , Duncan A. Forbes

We report preliminary results of the characterization of bulge and inner disk stellar populations for 8 nearby spiral galaxies using Gemini/GMOS. The long-slit spectra extend out to 1-2 disk scale lengths with S/N/Ang > 50. Two different…

Astrophysics · Physics 2009-11-13 Lauren A. MacArthur , Jesus Gonzalez , Stephane Courteau

CONTEXT. A number of recent papers have claimed the discovery of an X-shape structure in the bulge of our Galaxy in the population of the red clumps. AIMS. We endeavor to analyze the stellar density of bulge stars in the same regions using…

Astrophysics of Galaxies · Physics 2016-09-28 Martin Lopez-Corredoira

We investigate the assembly history of massive disk galaxies and describe how they shape their morphology through cosmic time. Using SHARDS and HST data, we modeled the surface brightness distribution of 91 massive galaxies at redshift…

We investigate the metallicity, age, and orbital anatomy of the inner Milky Way, specifically focussing on the outer bar region. We integrated a sample of APOGEE DR16 inner Galaxy stars in a state of the art bar-bulge potential with a slow…

Astrophysics of Galaxies · Physics 2022-03-16 Shola M. Wylie , Jonathan P. Clarke , Ortwin E. Gerhard

High resolution \'echelle spectra were obtained with the FEROS spectrograph at the 1.5m ESO telescope for 35 nearby bulge-like stars with metallicities in the range -0.8 $\leq$ [Fe/H] $\leq$ +0.4. Geneva photometry, astrometric data from…

Astrophysics · Physics 2009-11-07 Luciana Pompéia , Beatriz Barbuy , Michel Grenon

HST trigonometric distances, photometric metallicities, isochronic ages from the second revised version of the Geneva--Copenhagen survey, and uniform spectroscopic Fe and Mg abundances from our master catalog are used to construct and…

Astrophysics of Galaxies · Physics 2015-05-28 V. A. Marsakov , V. V. Koval' , T. V. Borkova , M. V. Shapovalov

Recent observations have revealed a population of $\alpha$-element abundances enhanced giant stars with unexpected high masses ($\gtrsim$1 $M_\odot$) from asteroseismic analysis and spectroscopy. Assuming single-star evolution, their masses…

This work is dedicated to investigation of galaxies that do not fit into a common scenario of galaxy formation - isolated lenticular galaxies. We have studied stellar populations and ionized gas content of a sample of 22 lenticular galaxies…

Astrophysics of Galaxies · Physics 2014-03-18 Ivan Yu. Katkov

The orbit distribution of young stars in the Galactic disk is highly structured, from well-defined clusters to streams of stars that may be widely dispersed across the sky, but are compact in orbital action-angle space. The age distribution…

Astrophysics of Galaxies · Physics 2023-11-20 Verena Fürnkranz , Hans-Walter Rix , Johanna Coronado , Rhys Seeburger

The bulge is the oldest component of the Milky Way. Since numerous simulations of Milky Way formation have predicted that the oldest stars at a given metallicity are found on tightly bound orbits, the Galaxy's oldest stars are likely…

Solar and Stellar Astrophysics · Physics 2020-09-30 Henrique Reggiani , Kevin C. Schlaufman , Andrew R. Casey , Alexander P. Ji

We present results of age determination based on the standard procedure of isochrone fitting for about 600 star clusters younger than about 1.2 Gyr from the central parts of the LMC. Comparison of age distributions of star clusters from the…

Astrophysics · Physics 2007-05-23 G. Pietrzynski , A. Udalski

In the Milky Way, the thick disk can be defined using individual stellar abundances, kinematics, or age; or geometrically, as stars high above the mid-plane. In nearby galaxies, where only a geometric definition can be used, thick disks…

Astrophysics of Galaxies · Physics 2016-11-09 Marie Martig , Ivan Minchev , Melissa Ness , Morgan Fouesneau , Hans-Walter Rix

Using the Mid-Infrared Spectrometer (MIRS) on board the Infrared Telescope in Space (IRTS) we obtained the 4.5 to 11.7 micron spectra of the stellar populations and diffuse interstellar medium in the Galactic bulge (l = 8.7 degree, b = 2.9,…

Astrophysics · Physics 2009-10-30 K. W. Chan , T. L. Roellig , T. Onaka , I. Yamamura , T. Tanabe

We present spectroscopic ages, metallicities, and [alpha/Fe] ratios for 70 globular clusters in M31 that were derived from Lick line-index measurements. In addition to a population of old (>10 Gyr) globular clusters with a wide range of…

Astrophysics · Physics 2009-11-10 Thomas H. Puzia , Kathy M. Perrett , Terry J. Bridges