Grants related:
General
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
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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On the Stellar Content of the Carina Dwarf Spheroidal Galaxy
We present deep, accurate, and homogeneous multiband optical (U, B, V, I) photometry of the Carina dwarf spheroidal galaxy, based on more than 4000 individual CCD images from three different ground-based telescopes. Special attention was given to the photometric calibration, and the precision for the B, V, and I bands is generally better than 0.01
Bono, G. et al.Advertised on:
52010 -
On the Relative Distances of ω Centauri and 47 Tucanae
We present precise optical and near-infrared ground-based photometry of two globular clusters (GCs): ω Cen and 47 Tuc. These photometric catalogs are unbiased in the red giant branch (RGB) region close to the tip. We provide new estimates of the RGB tip (TRGB) magnitudes-mI(TRGB)=9.84+/-0.05, ω Cen; mI(TRGB)=9.46+/-0.06, 47 Tuc-and use these to
Bono, G. et al.Advertised on:
102008 -
On the Radial Extent of the Dwarf Irregular Galaxy IC10
We present new deep and accurate space (Advanced Camera for Surveys-Wide Field Planetary Camera 2 on board the Hubble Space Telescope) and ground-based (Suprime-Cam at Subaru Telescope, Mega-Cam at Canada-France-Hawaii Telescope) photometric and astrometric data for the Local Group dwarf irregular IC10. We confirm the significant decrease of the
Sanna, N. et al.Advertised on:
102010 -
On the Radial Distribution of Horizontal Branch Stars in NGC 2808
We present accurate new ultraviolet and optical BVI photometry for the Galactic globular cluster NGC 2808 based on both ground-based and archival Hubble Space telescope imagery. From this we have selected a sample of ~2000 Horizontal Branch (HB) stars; given the extensive wavelength range considered and the combination of both high angular
Iannicola, G. et al.Advertised on:
52009 -
On the Distance and Reddening of the Starburst Galaxy IC 10
We present deep and accurate optical photometry of the Local Group starburst galaxy IC 10. The photometry is based on two sets of images collected with the Advanced Camera for Surveys and with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. We provide new estimates of the tip of the red giant branch (TRGB) magnitude
Sanna, N. et al.Advertised on:
122008 -
On the Absolute Age of the Globular Cluster M92
We present precise and deep optical photometry of the globular M92. Data were collected in three different photometric systems: Sloan Digital Sky Survey (g ', r ', i ', and z '; MegaCam at CFHT), Johnson-Kron-Cousins ( B , V , and I ; various ground-based telescopes), and Advanced Camera for Surveys (ACS) Vegamag (F475W, F555W, and F814W; Hubble
di Cecco, A. et al.Advertised on:
92010 -
On a New Parameter to Estimate the Helium Content in Old Stellar Systems
We introduce a new parameter Δξ-the difference in magnitude between the red giant branch (RGB) bump and the point on the main sequence (MS) at the same color as the bump (which we call the "benchmark")-to estimate the helium content in old stellar systems. The Δξ parameter is a helium indicator, since an increase in helium makes, at fixed age and
Troisi, F. et al.Advertised on:
82011 -
On a New Near-Infrared Method to Estimate the Absolute Ages of Star Clusters: NGC 3201 as a First Test Case
We present a new method to estimate the absolute ages of stellar systems. This method is based on the difference in magnitude between the main-sequence turnoff (MSTO) and a well-defined knee located along the lower main sequence (MSK). This feature is caused by the collisionally induced absorption of molecular hydrogen, and it can easily be
Bono, G. et al.Advertised on:
12010 -
Constraints on the formation of the globular cluster IC 4499 from multiwavelength photometry
We present new multiband photometry for the Galactic globular cluster IC 4499 extending well past the main-sequence turn-off in the U, B, V, R, I and DDO 51 bands. This photometry is used to determine that IC 4499 has an age of 12 ± 1 Gyr and a cluster reddening of E(B-V) = 0.22 ± 0.02. Hence, IC 4499 is coeval with the majority of Galactic
Walker, A. R. et al.Advertised on:
72011 -
The VLT/VISIR mid-IR view of 47 Tucanae. A further step in solving the puzzle of RGB mass loss
There is an ongoing debate regarding the onset luminosity of dusty mass loss in population-II red giant stars. We present VLT/VISIR mid-infrared (MIR) 8.6 μm imaging of 47 Tuc, the centre of attention of a number of space-based Spitzer observations and studies. The VISIR high-resolution (diffraction limited) observations allow excellent matching to
Momany, Y. et al.Advertised on:
12012 -
The two metallicity groups of the globular cluster M 22: a chemical perspective
We present a detailed chemical composition analysis of 35 red giant stars in the globular cluster M 22. High resolution spectra for this study were obtained at five observatories, and analyzed in a uniform manner. We have determined abundances of representative light proton-capture, α, Fe-peak and neutron-capture element groups. Our aim is to
Marino, A. F. et al.Advertised on:
82011 -
The Oxygen versus Sodium (Anti)Correlation(S) in ω Cen
Recent examination of large samples of ω Cen giants shows that, as in mono-metallic globular clusters, sodium versus oxygen anticorrelation is present within each subset of stars with iron content in the range -1.9
D'Antona, F. et al.Advertised on:
72011 -
The Infrared Eye of the Wide-Field Camera 3 on the Hubble Space Telescope Reveals Multiple Main Sequences of Very Low Mass Stars in NGC 2808
We use images taken with the infrared channel of the Wide Field Camera 3 on the Hubble Space Telescope to study the multiple main sequences (MSs) of NGC 2808. Below the turnoff, the red, the middle, and the blue MS, previously detected from visual-band photometry, are visible over an interval of about 3.5 F160W magnitudes. The three MSs merge
Milone, A. P. et al.Advertised on:
82012 -
The double sub-giant branch of NGC 6656 (M 22): a chemical characterization
We present an abundance analysis of 101 subgiant branch (SGB) stars in the globular cluster M 22. Using low-resolution FLAMES/GIRAFFE spectra we have determined abundances of the neutron-capture strontium and barium and the light element carbon. With these data we explore relationships between the observed SGB photometric split in this cluster and
Marino, A. F. et al.Advertised on:
52012 -
The C+N+O Abundance of ω Centauri Giant Stars: Implications for the Chemical-enrichment Scenario and the Relative Ages of Different Stellar Populations
We present a chemical-composition analysis of 77 red-giant stars in Omega Centauri. We have measured abundances for carbon and nitrogen, and combined our results with abundances of O, Na, La, and Fe that we determined in our previous work. Our aim is to better understand the peculiar chemical-enrichment history of this cluster by studying how the
Marino, A. F. et al.Advertised on:
22012 -
The Acs Survey of Globular Clusters. V. Generating a Comprehensive Star Catalog for each Cluster
The ACS Survey of Globular Clusters has used Hubble Space Telescope's Wide-Field Channel to obtain uniform imaging of 65 of the nearest globular clusters to provide an extensive homogeneous data set for a broad range of scientific investigations. The survey goals required not only a uniform observing strategy, but also a uniform reduction strategy
Anderson, Jay et al.Advertised on:
62008 -
The ACS survey of Galactic globular clusters. XII. Photometric binaries along the main sequence
Context. The fraction of binary stars is an important ingredient to interpret globular cluster dynamical evolution and their stellar population. Aims: We investigate the properties of main-sequence binaries measured in a uniform photometric sample of 59 Galactic globular clusters that were observed by HST WFC/ACS as a part of the Globular Cluster
Milone, A. P. et al.Advertised on:
42012 -
The ACS Survey of Galactic Globular Clusters. XI. The Three-dimensional Orientation of the Sagittarius Dwarf Spheroidal Galaxy and Its Globular Clusters
We use observations from the Hubble Space Telescope Advanced Camera for Surveys (HST/ACS) study of Galactic globular clusters to investigate the spatial distribution of the inner regions of the disrupting Sagittarius dwarf spheroidal galaxy (Sgr). We combine previously published analyses of four Sgr member clusters located near or in the Sgr core
Siegel, Michael H. et al.Advertised on:
122011 -
The ACS Survey of Galactic Globular Clusters. VIII. Effects of Environment on Globular Cluster Global Mass Functions
We have used observations obtained as part of the Hubble Space Telescope/ACS Survey of Galactic Globular Clusters to construct global present-day mass functions for 17 globular clusters utilizing multi-mass King models to extrapolate from our observations to the global cluster behavior. The global present-day mass functions for these clusters are
Paust, Nathaniel E. Q. et al.Advertised on:
22010 -
The ACS Survey of Galactic Globular Clusters. VII. Relative Ages
The ACS Survey of Galactic globular clusters is a Hubble Space Telescope Treasury program designed to provide a new large, deep, and homogeneous photometric database. Based on observations from this program, we have measured precise relative ages for a sample of 64 Galactic globular clusters by comparing the relative position of the clusters' main
Marín-Franch, A. et al.Advertised on:
42009
