Start year
1994
End year
2021
Organizational Unit
Organizing institutions
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.
Members
Principal investigator
Martín
López Corredoira
Project staff
Alfredo Rafael
Rosenberg González
Antonio
Aparicio Juan
Collaborators
Matteo
Monelli
Dr.
Elena Valenti
Dr.
J. Alonso
Dr.
D. Minniti
Dr.
M. Zoccali
Dr.
N. Arimoto
Dr.
S. Beaulieu
Dr.
R. Buonanno
Dr.
S. Cassisi
Dr.
A. Pietrinferni
Dr.
C. Jordi
Dr.
F. Figueras
Dr.
E. Kirby
Dr.
J. M. Carrrasco
Dr.
T. Mineikis
Dr.
A. Monachesi
Dr.
A. Piatti
Dr.
V. Nascimbeni
Dr.
G. Piotto
Dr.
E. Skillman
Dr.
A. del Pino
Results
Milestones
- Development of the web site http://basti-iac.oa-teramo.inaf.it for the BaSTI stellar evolution library
- 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
- Computation of a open access data base of "cromosomic maps" for all the object of the "HST Legacy Project on Globular Clusters".
- Determination of the star formation history of three Ultra-fain Dwarfs (UFD): Bootes I, Canes Venatici II y Leo IV
Scientific activity
Related publications
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The ACS Survey of Galactic Globular Clusters. VI. NGC 6366: A Heavily Stripped Galactic Globular ClusterWe have used observations obtained as part of the Hubble Space Telescope/ACS Survey of Galactic globular clusters (GCs) to construct a color-magnitude diagram for the bulge cluster, NGC 6366. The luminosity function derived from those data extends to M F606W ~ 9, or masses of ~0.3 M sun. Unlike most GCs, the mass function peaks near the mainPaust, Nathaniel E. Q. et al.
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12009 -
The ACS Survey of Galactic Globular Clusters. IX. Horizontal Branch Morphology and the Second Parameter PhenomenonThe horizontal branch (HB) morphology of globular clusters (GCs) is most strongly influenced by metallicity. The second parameter phenomenon, first described in the 1960s, acknowledges that metallicity alone is not enough to describe the HB morphology of all GCs. In particular, astronomers noticed that the outer Galactic halo contains GCs withDotter, Aaron et al.
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12010 -
The ACS Survey of Galactic Globular Clusters. III. The Double Subgiant Branch of NGC 1851Photometry with the Hubble Space Telescope Advanced Camera for Surveys (HST ACS) reveals that the subgiant branch (SGB) of the globular cluster NGC 1851 splits into two well-defined branches. If the split is due only to an age effect, the two SGBs would imply two star formation episodes separated by ~1 Gyr. We discuss other anomalies in NGC 1851Milone, A. P. et al.
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12008 -
Sodium-Oxygen Anticorrelation and Neutron-capture Elements in Omega Centauri Stellar PopulationsOmega Centauri is no longer the only globular cluster known to contain multiple stellar populations, yet it remains the most puzzling. Due to the extreme way in which the multiple stellar population phenomenon manifests in this cluster, it has been suggested that it may be the remnant of a larger stellar system. In this work, we present aMarino, A. F. et al.
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42011 -
NGC 2419: a large and extreme second generation in a currently undisturbed clusterWe analyse complementary Hubble Space Telescope and Subaru data for the globular cluster NGC 2419. We make a detailed analysis of the horizontal branch (HB), which is composed of two main groups of stars: the luminous blue HB stars, which extend by evolution into the RR Lyrae and red HB region, and a fainter, extremely blue population. We examinedi Criscienzo, M. et al.
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72011 -
Multiple Stellar Populations in 47 TucanaeWe use Hubble Space Telescope (HST) and ground-based imaging to study the multiple populations of 47 Tucanae (47 Tuc), combining high-precision photometry with calculations of synthetic spectra. Using filters covering a wide range of wavelengths, our HST photometry splits the main sequence into two branches, and we find that this duality isMilone, A. P. et al.
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12012 -
Luminosity and mass functions of the three main sequences of the globular cluster NGC 2808High-precision HST photometry has revealed that the globular cluster (GC) NGC 2808 hosts a triple main sequence (MS) corresponding to three stellar populations with different helium abundances. We carried out photometry on ACS/WFC HST images of NGC 2808 with the main purpose of measuring the luminosity function (LF) of stars in the three differentMilone, A. P. et al.
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12012 -
Hubble Space Telescope Observations of an Outer Field in Omega Centauri: A Definitive Helium AbundanceWe revisit the problem of the split main sequence (MS) of the globular cluster ω Centauri, and report the results of two-epoch Hubble Space Telescope observations of an outer field, for which proper motions give us a pure sample of cluster members, and an improved separation of the two branches of the MS. Using a new set of stellar models coveringKing, I. R. et al.
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72012 -
Age and helium content of the open cluster NGC 6791 from multiple eclipsing binary members. II. Age dependencies and new insightsContext. Models of stellar structure and evolution can be constrained by measuring accurate parameters of detached eclipsing binaries in open clusters. Multiple binary stars provide the means to determine helium abundances in these old stellar systems, and in turn, to improve estimates of their age. Aims: In the first paper of this series, weBrogaard, K. et al.
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72012 -
A new visual - near-infrared diagnostic to estimate the metallicity of cluster and field dwarf starsWe present a theoretical calibration of a new metallicity diagnostic based on the Strömgren index m1 and on visual - near-infrared (NIR) colors to estimate the global metal abundance of cluster and field dwarf stars. To perform the metallicity calibration we adopt α-enhanced evolutionary models transformed into the observational plane by usingCalamida, A. et al.
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82012 -
A Double Main Sequence in the Globular Cluster NGC 6397High-precision multi-band Hubble Space Telescope (HST) photometry reveals that the main sequence of the globular cluster NGC 6397 splits into two components, containing ~30% and ~70% of the stars. This double sequence is consistent with the idea that the cluster hosts two stellar populations: (1) a primordial population that has a compositionMilone, A. P. et al.
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12012 -
The young stellar population of IC 1613. I. A new catalogue of OB associationsContext: Determining the parameters of massive stars is crucial to understand many processes in galaxies and the Universe, since these objects are important sources of ionization, chemical enrichment and momentum. 10m class telescopes enable us to perform detailed quantitative spectroscopic analyses of massive stars in other galaxies, samplingGarcia, M. et al.
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82009 -
Washington photometry of five star clusters in the Large Magellanic CloudAims: We present CCD photometry in the Washington system C and T1 passbands down to T1 ~ 22.5 in the fields of NGC 1697, SL 133, NGC 1997, SL 663, and OHSC 28, five mostly unstudied star clusters in the LMC. Methods: Cluster radii were estimated from star counts in appropriate-sized boxes distributed throughout the entire observed fields. WePiatti, A. E. et al.
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72009 -
VLT/FORS1 spectrophotometry of the first planetary nebula discovered in the Phoenix dwarf galaxyContext: A planetary nebula (PN) candidate was discovered during FORS imaging of the Local Group dwarf galaxy Phoenix. Aims: We use this PN to complement abundances from red-giant stars. Methods: FORS spectroscopy was used to confirm the PN classification. Empirical methods and photoionization modeling were used to derive elemental abundances fromSaviane, I. et al.
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22009 -
The Proper Motion of the Magellanic Clouds. I. First Results and Description of the ProgramWe present the first results of a ground-based program to determine the proper motion of the Magellanic Clouds (MCs) relative to background quasars (QSO), being carried out using the Iréneé du Pont 2.5 m telescope at Las Campanas Observatory, Chile. Eleven QSO fields have been targeted in the Small Magellanic Cloud (SMC) over a time base of sixCosta, Edgardo et al.
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52009 -
The Disc-Halo Structure of NGC 3109We present the results of V and I photometries for ~56,500 stars of NGC 3109 obtained from a 467.26(')2 wide-field observations. The internal extinction does not affect the determination of the magnitude of the tip of the red giant branch (TRGB) from which a distance modulus of (m - M)0 = 25.61 ± 0.10 (1.32 ± 0.06 Mpc) have been derived. A meanHidalgo, Sebastian L. et al.
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122008 -
The ACS Nearby Galaxy Survey Treasury. I. The Star Formation History of the M81 Outer DiskThe Advanced Camera for Surveys (ACS) Nearby Galaxy Survey Treasury is a large Hubble Space Telescope (HST)/ACS treasury program to obtain resolved stellar photometry for a volume-limited sample of galaxies out to 4 Mpc. As part of this program, we have obtained deep ACS imaging of a field in the outer disk of the large spiral galaxy M81. The fieldWilliams, Benjamin F. et al.
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12009 -
The ACS Nearby Galaxy Survey TreasuryThe ACS Nearby Galaxy Survey Treasury (ANGST) is a systematic survey to establish a legacy of uniform multi-color photometry of resolved stars for a volume-limited sample of nearby galaxies (D 4 Mpc). The survey volume encompasses 69 galaxies in diverse environments, including close pairs, small and large groups, filaments, and truly isolatedDalcanton, Julianne J. et al.
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72009 -
The ACS LCID Project: RR Lyrae Stars as Tracers of Old Population Gradients in the Isolated Dwarf Spheroidal Galaxy TucanaWe present a study of the radial distribution of RR Lyrae variables, which present a range of photometric and pulsational properties, in the dwarf spheroidal galaxy Tucana. We find that the fainter RR Lyrae stars, having a shorter period, are more centrally concentrated than the more luminous, longer period RR Lyrae variables. Through comparisonBernard, Edouard J. et al.
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52008 -
The ACS LCID Project. VII. The Blue Stragglers Population in the Isolated dSph Galaxies Cetus and TucanaWe present the first investigation of the Blue Straggler star (BSS) population in two isolated dwarf spheroidal galaxies of the Local Group, Cetus and Tucana. Deep Hubble Space Telescope/Advanced Camera for Surveys photometry allowed us to identify samples of 940 and 1214 candidates, respectively. The analysis of the star formation histories of theMonelli, M. et al.
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12012
