Milky Way and Nearby Galaxies

Start year
1994
End year
2021
Organizational Unit

Grants related:

    General
    Description

    The general aim of the project is to research the structure, evolutionary history and formation of galaxies through the study of their resolved stellar populations, both from photometry and spectroscopy. The group research concentrates in the most nearby objects, namely the Local Group galaxies including the Milky Way and M33 under the hypothesis that they are a good representation of the general population of galaxies in the Universe.

    The project can be divided in four research lines:

    I. Star formation history in the Local Group.

    The goal is to characterise the spatial and temporal structure of the galaxies of the Local Group through the observations of individual stars. The fundamental aim is to derive the detailed star formation history (SFH) of a given galaxy in all its evolutionary stages, in order to determine the impact of cosmological (e.g. reionization, self-shielding) and local processes (e.g. gas sweeping by supernovas, tidal forces, stellar migration).

    II. Multiple stellar populations in globular clusters.

    At odds of what it is classically predicted, there is evidence that globular clusters (GC) host more than one stellar population with different chemical composition. HST photometric observations of GC show strong evidence of multiple main sequences in the CMDs. The aim of this line is to characterise the aforementioned multiple populations in GC.

    III. Structure and formation of the Milky Way.

    The main purpose of this research line is to study the Milky Way via by using GAIA data (spacebased), and the ESO-VVV survey (Vista Telescope). These data are going to provide a perfect opportunity to study the star formation history of the Galactic disk and bulge. In order to use GAIA and VVV data we need to adapt the tools developed by our group to study stellar populations.

    IV. Stellar evolution and synthetic color-magnitude diagram.

    We have developed a new stellar evolutionary library. There is the need in the scientific community to increase the reliability and accuracy in the stellar models computation using the most updated results in Physics, such as the equation of state, new opacities, and nuclear sections.

    Milestones

    1. Development of the web site http://basti-iac.oa-teramo.inaf.it for the BaSTI stellar evolution library
    2. Obtention of near-infrared PSF photometry of the full VVV disk region (220 sq. deg between 294.7° ≤ l ≤ 350.0° and |b| ≤ 2.25°) in J and Ks bands
    3. Computation of a open access data base of "cromosomic maps" for all the object of the "HST Legacy Project on Globular Clusters".
    4. Determination of the star formation history of three Ultra-fain Dwarfs (UFD): Bootes I, Canes Venatici II y Leo IV

    Related publications

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      Aims: XO-2 is the first confirmed wide stellar binary system where the almost twin components XO-2N and XO-2S have planets, and it is a peculiar laboratory in which to investigate the diversity of planetary systems. This stimulated a detailed characterization study of the stellar and planetary components based on new observations. Methods: We
      Damasso, M. et al.

      Advertised on:

      3
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    • The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. I. Overview of the Project and Detection of Multiple Stellar Populations
      In this paper we describe a new UV-initiative Hubble Space Telescope project (GO-13297) that will complement the existing F606W and F814W database of the Advanced Camera for Surveys Globular Cluster (GC) Treasury by imaging most of its clusters through UV/blue WFC3/UVIS filters F275W, F336W, and F438W. This “magic trio” of filters has shown an
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    • The Hubble Space Telescope UV Legacy Survey of galactic globular clusters - II. The seven stellar populations of NGC 7089 (M2)⋆
      We present high-precision multiband photometry for the globular cluster (GC) M2. We combine the analysis of the photometric data obtained from the Hubble Space Telescope UV Legacy Survey of Galactic GCs GO-13297, with chemical abundances by Yong et al., and compare the photometry with models in order to analyse the multiple stellar sequences we
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    • The nature and origin of substructure in the outskirts of M31 - II. Detailed star formation histories
      While wide-field surveys of M31 have revealed much substructure at large radii, understanding the nature and origin of this material is not straightforward from morphology alone. Using deep Hubble Space Telescope/Advanced Camera for Surveys data, we have derived further constraints in the form of quantitative star formation histories (SFHs) for 14
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    • A state-of-the-art analysis of the dwarf irregular galaxy NGC 6822
      We present a detailed photometric study of the dwarf irregular galaxy NGC 6822 aimed at investigating the properties of its stellar populations and, in particular, the presence of stellar radial gradients. Our goal is to analyse the stellar populations in six fields, which cover the whole bar of this dwarf galaxy. We derived the quantitative star
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      12
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    • On the missing second generation AGB stars in NGC 6752
      In recent years the view of Galactic globular clusters as simple stellar populations has changed dramatically, it is now thought that basically all globular clusters host multiple stellar populations, each with its own chemical abundance pattern and colour-magnitude diagram sequence. Recent spectroscopic observations of asymptotic giant branch
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    • The Carina Project. VII. Toward the Breaking of the Age-Metallicity Degeneracy of Red Giant Branch Stars Using the C U, B, I Index
      We present an analysis of photometric and spectroscopic data of the Carina dSph galaxy, testing a new approach similar to that used to disentangle multiple populations in Galactic globular clusters (GCs). We show that a proper color combination is able to separate a significant fraction of the red giant branch (RGB) of the two main Carina
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    • Adventures of a tidally induced bar
      Using N-body simulations, we study the properties of a bar induced in a discy dwarf galaxy as a result of tidal interaction with the Milky Way. The bar forms at the first pericentre passage and survives until the end of the evolution at 10 Gyr. Fourier decomposition of the bar reveals that only even modes are significant and preserve a hierarchy so
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    • Delayed Star Formation in Isolated Dwarf galaxies: Hubble Space Telescope Star Formation History of the Aquarius Dwarf Irregular
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    • Andromeda II as a merger remnant
      Using N-body simulations, we study the origin of prolate rotation observed in the kinematic data for Andromeda II (And II), a dwarf spheroidal satellite of M31. We propose an evolutionary model for the origin of And II involving a merger between two discy dwarf galaxies with different disc scalelengths. The dwarfs are placed on a radial orbit
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    • The age-metallicity relationship in the Fornax spheroidal dwarf galaxy
      We produce a comprehensive field star age-metallicity relationship (AMR) from the earliest epoch until ˜1 Gyr ago for three fields in the Fornax dwarf spheroidal galaxy by using VI photometric data obtained with FORS1 at the VLT. We find that the innermost one does not contain dominant very old stars (age > 12 Gyr), whereas the relatively outer
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    • The VVV Templates Project Towards an automated classification of VVV light-curves. I. Building a database of stellar variability in the near-infrared
      Context. The Vista Variables in the Vía Láctea (VVV) ESO Public Survey is a variability survey of the Milky Way bulge and an adjacent section of the disk carried out from 2010 on ESO Visible and Infrared Survey Telescope for Astronomy (VISTA). The VVV survey will eventually deliver a deep near-IR atlas with photometry and positions in five
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    • The halo+cluster system of the Galactic globular cluster NGC 1851
      NGC 1851 is surrounded by a stellar component that extends more than 10 times beyond the tidal radius. Although the nature of this stellar structure is not known, it has been suggested to be a sparse halo of stars or associated with a stellar stream. We analyse the nature of this intriguing stellar component surrounding NGC 1851 by investigating
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      8
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    • Comparing M31 and Milky Way Satellites: The Extended Star Formation Histories of Andromeda II and Andromeda XVI
      We present the first comparison between the lifetime star formation histories (SFHs) of M31 and Milky Way (MW) satellites. Using the Advanced Camera for Surveys on board the Hubble Space Telescope, we obtained deep optical imaging of Andromeda II (And II; MV = -12.0 log(M sstarf/M ⊙) ~ 6.7) and Andromeda XVI (And XVI; MV = -7.5 log(M sstarf/M ⊙) ~
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    • The ACS LCID Project. X. The Star Formation History of IC 1613: Revisiting the Over-cooling Problem
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    • Global and Nonglobal Parameters of Horizontal-branch Morphology of Globular Clusters
      The horizontal-branch (HB) morphology of globular clusters (GCs) is mainly determined by metallicity. However, the fact that GCs with almost the same metallicity exhibit different HB morphologies demonstrates that at least one more parameter is needed to explain the HB morphology. It has been suggested that one of these should be a global parameter
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    • The Na-O anticorrelation in horizontal branch stars. IV. M 22
      We obtained high-resolution spectra for 94 candidate stars belonging to the HB of M 22 with FLAMES. Previous works have indicated that this cluster has split subgiant (SGB) and red giant branches (RGB) and hosts two different stellar populations, differing in overall metal abundance and both exhibiting a Na-O anti-correlation. The HB stars we
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    • On the Kinematic Separation of Field and Cluster Stars across the Bulge Globular NGC 6528
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    • Spatially resolved LMC star formation history - I. Outside in evolution of the outer LMC disc
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    • The ACS Survey of Globular Clusters. XIII. Photometric Calibration in Comparison with Stetson Standards
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