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We describe a first attempt to apply adaptive optics to the study of resolved stellar populations in galaxies. Advantages over traditional approaches are (i) improved spatial resolution and point-source sensitivity through adaptive optics,…

Astrophysics · Physics 2007-05-23 T. R. Bedding , D. Minniti , F. Courbin , B. Sams

Multi-color photometry of the stellar populations in five fields in the third Galactic quadrant centred on the clusters NGC 2215, NGC 2354, Haffner 22, Ruprecht 11, and ESO489SC01 is interpreted in terms of a warped and flared Galactic…

Astrophysics of Galaxies · Physics 2015-12-09 Giovanni Carraro , Anton F. Seleznev , Gustavo L. Baume , David G. Turner

We investigate the nature of the innermost regions of seven circumstellar disks around pre-main-sequence stars. Our object sample contains disks apparently at various stages of their evolution. Both single stars and spatially resolved…

Solar and Stellar Astrophysics · Physics 2015-05-13 A. A. Schegerer , S. Wolf , C. A. Hummel , S. P. Quanz , A. Richichi

Several recent studies indicate that bulges are more complex than merely structureless relaxed stellar systems. We study the HST images of a sample of 130 nearby early type (S0-Sab) disc galaxies and detect pure structureless bulges with…

Astrophysics · Physics 2008-10-16 Leonel Gutierrez , Antti Tamm , John Beckman , Louis Abramson , Peter Erwin , Melanie Guittet

We present a new determination of the metallicity distribution, age, and luminosity function of the Galactic bulge stellar population. By combining near-IR data from the 2MASS survey, from the SOFI imager at ESO NTT and the NICMOS camera on…

(Abridged) A variety of formation scenarios was proposed to explain the diversity of properties observed in bulges. Studying their intrinsic shape can help in constraining the dominant mechanism at the epochs of their assembly. The…

Astrophysics · Physics 2015-05-13 J. Mendez-Abreu , J. A. L. Aguerri , E. M. Corsini , E. Simonneau

We performed a photometric multicolor survey of the core of the Canis Major over-density at l 244, -8.0, reaching V = 22 and covering 0.3 x 1 degree. The main aim is to unravel the complex mixture of stellar populations toward this Galactic…

Astrophysics · Physics 2009-11-13 Giovanni Carraro , Andre' Moitinho , Ruben A. Vazquez

Panchromatic spectral energy distribution (SED) from the ultraviolet (UV), optical to infrared (IR) photometry of NGC 628, combined with the evolutionary stellar population synthesis, is used to derive the spatially resolved age,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Hu Zou , Wei Zhang , Yanbin Yang , Xu Zhou , Zhaoji Jiang , Jun Ma , Zhenyu Wu , Jianghua Wu , Tianmeng Zhang , Zhou Fan

We present new proper motions from the 10 m Keck telescopes for a puzzling population of massive, young stars located within 3.5" (0.14 pc) of the supermassive black hole at the Galactic Center. Our proper motion measurements have…

Astrophysics · Physics 2011-02-11 J. R. Lu , A. M. Ghez , S. D. Hornstein , M. R. Morris , E. E. Becklin , K. Matthews

Context. Bulges, located at the central regions of galaxies, are complex structures, expected to be shaped by the physical processes involved in the assembly history of their host galaxy, such as gravitational collapse, mergers,…

We present Hubble Space Telescope blue spectra at intermediate spectral resolution for the nuclei of 23 nearby disk galaxies. These objects were selected to have nebular emission in their nuclei, and span a range of emission-line…

We have obtained 2D spectral data for a sample of 58 nearby S0 galaxies with the Multi-Pupil Spectrograph of the 6m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. The Lick indices H-beta, Mgb, and…

Astrophysics · Physics 2009-11-13 Olga K. Sil'chenko

We present an analysis of high latitude $\delta$ Scuti stars ($\left|b\right|> 1^{\circ}$) in the Galactic bulge region ($-8^{\circ}.3< l<9^{\circ}.4$) using a clean sample of the photometric data of $7,440$ stars recently released by the…

Astrophysics of Galaxies · Physics 2022-08-30 Mami Deka , Sukanta Deb , Kerdaris Kurbah

(Abridged) We report on the structure of the nuclear star cluster in the innermost 0.16 pc of the Galaxy as measured by the number density profile of late-type giants. Using laser guide star adaptive optics in conjunction with the integral…

Astrophysics of Galaxies · Physics 2010-02-10 Tuan Do , Andrea M. Ghez , Mark R. Morris , Jessica R. Lu , Keith Matthews , Sylvana Yelda , Shelley Wright , James Larkin

An observational survey of stars selected from the region of sky in the direction of the Galactic bulge is presented. We discuss the choice of tracer populations for this study. Digitised UK Schmidt plate photometry, calibrated with CCD…

Astrophysics · Physics 2015-06-24 Rodrigo Ibata , Gerard Gilmore

Stellar photometry of nearby irregular galaxies of the Local Group is used to identify and study the young and old stellar populations of these galaxies. An analysis of the spatial distributions of stars of different ages in face-on…

Astrophysics · Physics 2009-11-11 N. A. Tikhonov

We use the bulge Sersic index n and bulge-to-total ratio (B/T) to explore the fundamental question of how bulges form. We perform 2D bulge-disk-bar decomposition on H-band images of 143 bright, high stellar mass (>1.0e10 solar masses)…

Astrophysics · Physics 2014-11-18 Tim Weinzirl , Shardha Jogee , Sadegh Khochfar , Andreas Burkert , John Kormendy

We explore stellar population properties separately in the bulge and the disk of double-component cluster galaxies to shed light on the formation of lenticular galaxies in dense environments. We study eight low-redshift clusters from the…

We present a brief summary of our current results on the stellar distribution and population gradients of the resolved stars in the surroundings of ~50 nearby disk galaxies, observed with space- (Hubble & Spitzer) and ground-based…

Based on an almost complete sample of Galactic open star clusters within 1.8 kpc, we perform a comprehensive statistical analysis of various cluster parameters like spatial position, age, size, mass and extinction in order to understand the…

Astrophysics of Galaxies · Physics 2016-10-18 Yogesh C. Joshi , Andrei Dambis , Anil K. Pandey , Santosh Joshi