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Related papers: Unravelling stellar populations in the Andromeda G…

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We present analysis of nearly 1,000 near-infrared, integrated light spectra from APOGEE in the inner $\sim$7 kpc of M31. We utilize full spectrum fitting with A-LIST simple stellar population spectral templates that represent a population…

The metallicity distribution function (MDF) of the Galactic bulge features a multi-peak shape, with a metal-poor peak at [Fe/H]=-0.3 dex and a metal-rich peak at [Fe/H]=+0.3 dex. This bimodality is also seen in [alpha/Fe] versus [Fe/H]…

Astrophysics of Galaxies · Physics 2024-05-22 M. Molero , F. Matteucci , E. Spitoni , A. Rojas-Arriagada , R. M. Rich

We present the first self-consistent chemodynamical model fitted to reproduce data for the galactic bulge, bar and inner disk. We extend the Made-to-Measure method to an augmented phase-space including the metallicity of stars, and show its…

Astrophysics of Galaxies · Physics 2017-07-05 Matthieu Portail , Christopher Wegg , Ortwin Gerhard , Melissa Ness

We present the discovery of an inhomogenous, low-surface brightness, extended disk-like structure around the Andromeda galaxy (M31) based on a large kinematic survey of more than 2800 stars with the Keck/DEIMOS spectrograph. The stellar…

Astrophysics · Physics 2008-11-26 R. Ibata , S. Chapman , A. M. N. Ferguson , G. Lewis , M. Irwin , N. Tanvir

We have used Hubble Space Telescope Wide Field Planetary Camera 2 observations to construct a color-magnitude diagram (CMD) for the bulge of M31 at a location ~1.6 kpc from the galaxy's center. Using scaled-solar abundance theoretical red…

Astrophysics · Physics 2008-11-26 Ata Sarajedini , Pascale Jablonka

We describe a novel framework to model galaxy spectra with two cospatial stellar populations, such as may represent a bulge & bar or thick & thin disc, and apply it to APOGEE spectra in the inner $\sim$2 kpc of M31, as well as to stacked…

Due to its proximity, the stellar populations of the Galactic bulge (GB) can be resolved and can be studied in detail. This allows tracing the bulge metallicity distribution function (MDF) for different spatial regions within the bulge,…

Astrophysics of Galaxies · Physics 2023-02-08 Oscar Cavichia , Mercedes Mollá , Juanjo J. Bazán

We have obtained long-slit spectroscopy for a sample of 20 early-type barred galaxies to study the influence of bars in the building of galaxy bulges. Line strength indices were measured and used to derive age and metallicity gradients in…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Isabel Perez , Patricia Sanchez-Blazquez

We explore the chemodynamical properties of the Galaxy in the azimuthal velocity $V_\phi$ and metallicity [Fe/H] space using red giant stars from Gaia Data Release 3. The row-normalized $V_\phi$-[Fe/H] maps form a coherent sequence from the…

Astrophysics of Galaxies · Physics 2024-03-28 Xiaojie Liao , Zhaoyu Li , Iulia Simion , Juntai Shen , Robert Grand , Francesca Fragkoudi , Federico Marinacci

We re-analyse photometric near-infrared data in order to investigate why it is so hard to get a consensus for the shape and density law of the bulge, as seen from the literature. To solve the problem we use the Besancon Galaxy Model to…

Astrophysics of Galaxies · Physics 2015-06-03 Annie C. Robin , Douglas J. Marshall , Mathias Schultheis , Celine Reyle

The origin of the high-alpha component of the Galactic bulge remains debated, unlike the bar-driven origin of the low-alpha bulge. We examine the metallicity-dependent dynamical properties of high-[Mg/Fe] stars in the bar region, using…

Astrophysics of Galaxies · Physics 2025-09-19 Aakash Pandey , Ortwin Gerhard

By definition, Population III stars are metal-free, and their protostellar collapse is driven by molecular hydrogen cooling in the gas-phase, leading to large characteristic masses. Population II stars with lower characteristic masses form…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 John H. Wise , Matthew J. Turk , Michael L. Norman , Tom Abel

Constraints on the Galactic bulge/bar structure and formation history from stellar kinematics and metallicities mainly come from relatively high-latitude fields (|b|>4) where a complex mix of stellar population is seen. We aim here to…

We present a study of spatial variations in the metallicity of old red giant branch stars in the Andromeda galaxy. Photometric metallicity estimates are derived by interpolating isochrones for over seven million stars in the Panchromatic…

This is the second paper of a series aimed to study the stellar kinematics and population properties of bulges in highly-inclined barred galaxies. In this work, we carry out a detailed analysis of the stellar age, metallicity and [Mg/Fe] of…

HST-WFPC2 F555W and F814W photometry were obtained for 16 fields of the luminous nearby spiral galaxy M31, sampling the stellar content of the disk and the halo at different distances from the center, from ~ 20 to ~ 150 arcmin (i.e. ~ 4.5…

Astrophysics · Physics 2011-07-18 M. Bellazzini , C. Cacciari , L. Federici , F. Fusi Pecci , R. M. Rich

The characteristics of the stellar populations in the Galactic Bulge inform and constrain the Milky Way's formation and evolution. The metal-poor population is particularly important in light of cosmological simulations, which predict that…

We present an analysis of the large-scale structure of the halo of the Andromeda galaxy, based on the Pan-Andromeda Archeological Survey (PAndAS), currently the most complete map of resolved stellar populations in any galactic halo. Despite…

We present a model for the [alpha/Fe]-[Fe/H] distribution of stars in the inner Galaxy, R=3-5 kpc, measured as a function of vertical distance |z| from the midplane by Hayden et al. (2015, H15). Motivated by an "upside-down" scenario for…

Astrophysics of Galaxies · Physics 2017-11-01 Jenna K. C. Freudenburg , David H. Weinberg , Michael R. Hayden , Jon A. Holtzman

Stellar kinematics and metallicity are key to exploring formation scenarios for galactic disks and halos. In this work, we characterized the relationship between kinematics and photometric metallicity along the line-of-sight to M31's disk.…

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