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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Searching for chemical inhomogeneities in open clusters. Analysis of the CN and CH molecular band strengths in NGC 2158, NGC 2420, NGC 2682, NGC 7789, and Berkeley 29Context. The total mass of a cluster, which is the main parameter determining its ability to host more than one stellar generation, may constitute a threshold below which the cluster is able to form only a single stellar population. Aims: Our goal is to investigate the existence of star-to-star variations in CN and CH band strengths, which areCarrera, R. et al.
Advertised on:
122013 -
The ACS LCID Project. IX. Imprints of the Early Universe in the Radial Variation of the Star Formation History of Dwarf GalaxiesBased on Hubble Space Telescope observations from the Local Cosmology from Isolated Dwarfs project, we present the star formation histories, as a function of galactocentric radius, of four isolated Local Group dwarf galaxies: two dSph galaxies, Cetus and Tucana, and two transition galaxies (dTrs), LGS-3 and Phoenix. The oldest stellar populationsHidalgo, S. L. et al.
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122013 -
The BaSTI Stellar Evolution Database: models for extremely metal-poor and super-metal-rich stellar populationsWe present an extension of the BaSTI (Bag of Stellar Tracks and Isochrones) stellar evolution database to extremely metal-poor (Z = 10-5) and super-metal-rich (Z = 0.05) metallicities, with both scaled-solar and α-enhanced ([α/Fe] = 0.4) heavy element distributions. These new tracks (from the pre-main sequence to the early-asymptotic giant branchPietrinferni, A. et al.
Advertised on:
102013 -
Multi-wavelength Hubble Space Telescope Photometry of Stellar Populations in NGC 288We present new UV observations for NGC 288, taken with the WFC3 detector on board the Hubble Space Telescope, and combine them with existing optical data from the archive to explore the multiple-population phenomenon in this globular cluster (GC). The WFC3's UV filters have demonstrated an uncanny ability to distinguish multiple populations alongPiotto, G. et al.
Advertised on:
92013 -
Multiple stellar populations in Magellanic Cloud clusters. II. Evidence also in the young NGC 1844?We used Hubble Space Telescope observations to study the young cluster NGC 1844 in the Large Magellanic Cloud (LMC). We estimated the fraction and the mass-ratio distribution of photometric binaries and report that the main sequence presents an intrinsic breadth which cannot be explained only in terms of photometric errors, and is unlikely becauseMilone, A. P. et al.
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72013 -
TraMoS project - III. Improved physical parameters, timing analysis and starspot modelling of the WASP-4b exoplanet system from 38 transit observationsWe report 12 new transit observations of the exoplanet WASP-4b from the Transit Monitoring in the South (TraMoS) project. These transits are combined with all previously published transit data for this planet to provide an improved radius measurement of Rp = 1.395 ± 0.022Rjup and improved transit ephemerides. In a new homogeneous analysis in searchHoyer, S. et al.
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92013 -
The near-infrared Ca II triplet as a metallicity indicator - II. Extension to extremely metal-poor metallicity regimesWe extend our previous calibration of the infrared Ca II triplet (CaT) as a metallicity indicator to the metal-poor regime by including observations of 55 field stars with [Fe/H] down to -4.0 dex. While we previously solved the saturation at high metallicity using a combination of a Lorentzian and a Gaussian to reproduce the line profiles, in thisCarrera, R. et al.
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92013 -
Spatial dependence of the star formation history in the central regions of the Fornax dwarf spheroidal galaxyWe present the star formation history (SFH) and the age-metallicity relation (AMR) in three fields of the Fornax dwarf spheroidal galaxy. They sample a region spanning from the centre of the galaxy to beyond one core radius, which allows studying galactocentric gradients. In all the cases, we found stars as old as 12 Gyr, together with intermediatedel Pino, A. et al.
Advertised on:
82013 -
The ACS LCID Project - VIII. The short-period Cepheids of Leo AWe present the results of a new search for variable stars in the Local Group dwarf galaxy Leo A, based on deep photometry from the Advanced Camera for Surveys onboard the Hubble Space Telescope. We detected 166 bona fide variables in our field, of which about 60 per cent are new discoveries and 33 candidate variables. Of the confirmed variables, weBernard, Edouard J. et al.
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72013 -
The SUMO project I. A survey of multiple populations in globular clustersWe present a general overview and the first results of the SUMO project (a SUrvey of Multiple pOpulations in Globular Clusters). The objective of this survey is the study of multiple stellar populations in the largest sample of globular clusters homogeneously analysed to date. To this aim we obtained high signal-to-noise (S/N > 50) photometry forMonelli, M. et al.
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52013 -
Horizontal Branch Morphology and Multiple Stellar Populations in the Anomalous Globular Cluster M 22M 22 is an anomalous globular cluster that hosts two groups of stars with different metallicity and s-element abundance. The star-to-star light-element variations in both groups, with the presence of individual Na-O and C-N anticorrelations, demonstrates that this Milky Way satellite has experienced a complex star formation history. We haveMarino, A. F. et al.
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52013 -
A WFC3/HST View of the Three Stellar Populations in the Globular Cluster NGC 6752Multi-band Hubble Space Telescope photometry reveals that the main sequence, sub-giant, and the red-giant branch of the globular cluster NGC 6752 splits into three main components in close analogy with the three distinct segments along its horizontal branch stars. These triple sequences are consistent with three stellar groups: a stellar populationYong, D. et al.
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42013 -
On the Density Profile of the Globular Cluster M92We present new number density and surface brightness profiles for the globular cluster M92 (NGC 6341). These profiles are calculated from optical images collected with the CCD mosaic camera MegaCam at the Canada-France-Hawaii Telescope and with the Advanced Camera for Surveys on the Hubble Space Telescope. The ground-based data were supplementedWalker, A. R. et al.
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42013 -
The Intriguing Stellar Populations in the Globular Clusters NGC 6388 and NGC 6441NGC 6388 and NGC 6441 are two massive Galactic bulge globular clusters that share many properties, including the presence of an extended horizontal branch (HB), quite unexpected because of their high metal content. In this paper we use Hubble Space Telescope's WFPC2, ACS, and WFC3 images and present a broad multicolor study of their stellar contentPiotto, G. et al.
Advertised on:
32013 -
KIC 10449976: discovery of an extreme helium subdwarf in the Kepler fieldOptical spectroscopy of the blue star KIC 10449976 shows that it is an extremely helium-rich subdwarf with effective temperature Teff = 40 000 ± 300 K and surface gravity log g = 5.3 ± 0.1. Radial-velocity measurements over a 5 d time-scale show an upper variability limit of ≈50 ± 20 km s-1. Kepler photometry of KIC 10449976 in both long and shortBarclay, T. et al.
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32013 -
TASTE. III. A homogeneous study of transit time variations in WASP-3bThe TASTE project is searching for low-mass planets with the transit timing variation (TTV) technique by gathering high-precision, short-cadence light curves for a selected sample of transiting exoplanets. It has been claimed that the "hot Jupiter" WASP-3b could be perturbed by a second planet. Presenting eleven new light curves (secured at theMalavolta, L. et al.
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12013 -
Carbon and nitrogen abundances of stellar populations in the globular cluster M 2We present CH and CN index analysis and C and N abundance calculations based on the low-resolution blue spectra of red giant branch (RGB) stars in the Galactic globular cluster NGC 7089 (M 2). Our main goal is to investigate the C-N anticorrelation for this intermediate metallicity cluster. The data were collected with DOLORES, the multiobject, lowMilone, A. P. et al.
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122012 -
Analysis of the CN and CH Molecular Band Strengths in Stars of the Open Cluster NGC 6791Low-resolution SDSS/SEGUE spectra have been used to study the behavior of the strengths of the CN and CH molecular bands in stars at different evolutionary stages of the open cluster NGC 6791. We find a significant spread in the strengths of the CN bands, more than twice that expected from the uncertainties, although the bimodalities observed inCarrera, R. J.
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102012 -
Hubble Space Telescope Reveals Multiple Sub-giant Branch in Eight Globular ClustersIn the last few years many globular clusters (GCs) have revealed complex color-magnitude diagrams, with the presence of multiple main sequences (MSs), broad or multiple sub-giant branches (SGBs) and MS turnoffs, and broad or split red giant branches (RGBs). After a careful correction for differential reddening, high-accuracy photometry with thePiotto, G. et al.
Advertised on:
112012 -
VV124 (UGC4879): a new transitional dwarf galaxy in the periphery of the Local GroupWe present the first photometry of individual stars within VV124 (UGC4879) and find that this is the most isolated dwarf galaxy in the periphery of the Local Group. This work is based on imaging and spectroscopic follow-up observations with the 6-m BTA telescope; we resolve VV124 into 1560 stars down to the limiting magnitude levels of V ~= 25.6Kopylov, A. I. et al.
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