A5050089650- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Galaxies: Formation, Evolution, Phenomena
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Astronomical and nuclear sciences
- History and Developments in Astronomy
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Impact of Light on Environment and Health
- Geomagnetism and Paleomagnetism Studies
- Spectroscopy and Laser Applications
- Pigment Synthesis and Properties
- Atmospheric Ozone and Climate
- X-ray Spectroscopy and Fluorescence Analysis
- Astrophysics and Cosmic Phenomena
- Geology and Paleoclimatology Research
- Adaptive optics and wavefront sensing
- Isotope Analysis in Ecology
- Pulsars and Gravitational Waves Research
Yunnan University
2023-2025
Osservatorio Astronomico di Padova
2018-2023
University of Padua
2018-2023
National Institute for Astrophysics
2020-2021
Universidad de La Laguna
2016-2018
Instituto de Astrofísica de Canarias
2016-2018
Osservatorio astronomico di Bologna
2015
University of Bologna
2014
University of Rome Tor Vergata
2012-2014
Recent work, based on data from the Hubble Space Telescope (HST ) UV Legacy Survey of Galactic Globular Clusters (GCs), has revealed that all analysed clusters host two groups first- (1G) and second-generation (2G) stars. In most GCs, both 1G 2G stars substellar populations with different chemical composition. We compare multiwavelength HST photometry synthetic spectra to determine for first time average helium difference between in a large sample 57 GCs maximum variation within each them....
The split main sequences (MSs) and extended MS turnoffs (eMSTOs) detected in a few young clusters have demonstrated that these stellar systems host multiple populations differing number of properties such as rotation and, possibly, age.We analyze Hubble Space Telescope photometry for thirteen with ages between ~40 ~1000 Myrs different masses. Our goal is to investigate the first time occurrence large sample clusters. We find all exhibit eMSTO phenomenon stars more massive than ~1.6 solar...
The HST UV Survey of Globular Clusters (GCs) has investigated GCs and their stellar populations. In previous papers this series we have introduced a pseudo two-color diagram, "chromosome map" (ChM), that maximises the separation between multiple We identified two main classes GCs: Type I (~83% objects) II, both hosting groups stars, referred to in as first (1G) second generation (2G). II clusters exhibit or more parallel sequences 1G 2G stars ChMs. exploit elemental abundances from...
We present photometric analysis of twelve Galactic open clusters and show that the same multiple-population phenomenon observed in Magellanic Clouds (MCs) is nearby clusters. Nearly all younger than $\sim$2.5 Gyr both MCs exhibit extended main-sequence turnoffs (eMSTOs) cluster $\sim$700 Myr broadened/split main sequences (MSs). High-resolution spectroscopy has revealed these host stars with a large spread projected rotations. In addition to rotation, internal age variation indicated as...
The 'chromosome map' diagram (ChM) proved a successful tool to identify and characterize multiple populations (MPs) in 59 Galactic Globular Clusters (GCs). Here, we construct ChMs for 11 GCs of both Magellanic Clouds (MCs) with different ages compare MPs extra-Galactic environments, explore whether this phenomenon is universal through 'place' 'time'. are detected five clusters. fractions 1G stars, ranging from about 50% more than 80%, significantly higher those observed similar present-day...
In the past years, we have undertaken an extensive investigation of LMC and SMC star clusters based on HST data. We present photometry astrometry stars in 101 fields observed with WFC/ACS, UVIS/WFC3 NIR/WFC3 cameras. These comprise 113 clusters. provide differential-reddening maps illustrate various scientific outcomes that arise from early inspection photometric catalogs. particular, new insights extended main-sequence turn-off (eMSTO) phenomenon: i) detected eMSTOs two clusters, KMHK361...
Binary stars play a crucial role in our understanding of the formation and evolution star clusters their stellar populations. We use Gaia Data Release 3 to homogeneously analyze 78 Galactic open unresolved binary systems they host, each composed two main sequence (MS) stars. first investigated structural parameters these clusters, such as core radius central density, determined cluster mass function (MF) total by interpolating density profile cluster. measured fraction binaries with large...
Abstract The pseudo two-color diagram, known as chromosome map (ChM), is a valuable tool for identifying globular clusters (GCs), which consist of single or multiple stellar populations (MPs). Recent surveys Galactic GCs using ChMs have provided stringent observational constraints on the formation and their populations. However, these primarily focused at moderate distances from center composed MPs. In this paper, we present first detailed study composition four in outer halo Milky Way: Arp...
ABSTRACT We present a detailed analysis of the internal dynamics multiple stellar populations (MPs) in 28 Galactic globular clusters (GCs) across wide field view, extending from innermost regions to clusters’ outskirts. Using astrophotometric catalogues ground-based observations, Gaia and Hubble Space Telescope (HST), we identify first- (1P) second-population (2P) stars, study MPs using high-precision DR3 HST proper motions. Our results reveal that while 1P transitions isotropy slight...
One of the most unexpected results in field stellar populations last few years, is discovery that some Magellanic-Cloud globular clusters younger than ~400 Myr, exhibit bimodal main sequences (MSs) their color-magnitude diagrams (CMDs). Moreover, these young host an extended sequence turn off (eMSTO) close analogy with what observed ~1-2 Gyr old both Magellanic Clouds. We use high-precision Hubble-Space-Telescope photometry to study star cluster NGC1866 Large Cloud. discover eMSTO and a...
Disentangling distinct stellar populations along the red-giant branches (RGBs) of Globular Clusters (GCs) is possible by using pseudo two-color diagram dubbed chromosome map (ChM). One most intriguing findings that so-called first-generation (1G) stars, characterized same chemical composition their natal cloud, exhibit extended sequences in ChM. Unresolved binaries and internal variations helium or metallicity have been suggested to explain this phenomenon. Here, we derive high-precision...
We use images collected with the near-infrared camera (NIRCam) on board James Webb Space Telescope and Hubble (HST) to investigate multiple populations at bottom of main sequence (MS) 47 Tucanae. The F115W vs. F115W-F322W2 CMD from NIRCam shows that, below knee, MS stars span a wide color range, where majority M-dwarfs exhibit blue colors, tail are distributed toward red. A similar pattern is observed F160W F110W-F160W HST, also visible in optical F606W F606W-F814W CMD. narrow faint masses...
Abstract James Webb Space Telescope (JWST) observations have been demonstrated to be efficient in detecting multiple stellar populations globular clusters (GCs) the low-mass regime of M dwarfs. We present an overview, and first results, different projects that can explored by using JWST gathered under program GO2560 for 47 Tucanae, entirely devoted investigation very-low-mass stars, which includes spectroscopic data faintest GC stars spectra are available. Our color–magnitude diagram (CMD)...
The series of events, which occurred at high redshift and originated multiple stellar populations in Globular Clusters (GCs) are still poorly understood. Theoretical work suggests that the present-day dynamics stars nearby GCs, including rotation velocity dispersion, may retain important clues on formation populations. So far, have been investigated either from radial velocities a relatively-small sample stars, or relative proper motions small field view provided by Hubble Space Telescope....
Abstract The multiple stellar populations (MPs) of the ∼11–13 Gyr old globular clusters (GCs) in our Galaxy are characterized by different content several light elements. These elements describe well-defined patterns like C–N and Na–O anticorrelations He–N Na–N correlations. discovery MPs Magellanic Cloud GCs opened up new paths for investigation chemical anomalies with ages physical properties. In this context, we used Hubble Space Telescope photometry to investigate constrain their...
ABSTRACT The location of Galactic globular clusters’ (GC) stars on the horizontal branch (HB) should mainly depend GC metallicity, ‘first parameter’, but it is actually result complex interactions between red giant (RGB) mass-loss, coexistence multiple stellar populations with different helium content, and presence a ‘second parameter’ that produces dramatic differences in HB morphology GCs similar metallicity ages (like pair M3–M13). In this work, we combine entire data set from Hubble...
ABSTRACT The presence of differential reddening in the direction Galactic globular clusters (GCs) has proven to be a serious limitation traditional colour–magnitude diagram (CMD) analysis. Here, we estimate local variations 56 GCs. To do that, use public catalogues derived as part Hubble Space Telescope UV Legacy Survey GCs, which include photometry F275W, F336W, F438W, F606W, and F814W filters. We corrected for found that 21 out GCs adopted correction procedure significantly improved CMDs....
Recent work on metal-intermediate globular clusters (GCs) with [Fe/H]=$-1.5$ and $-0.75$ has illustrated the theoretical behavior of multiple populations in photometric diagrams obtained James Webb Space Telescope (JWST). These results are confirmed by observations among M-dwarfs 47 Tucanae. Here, we explore metal-poor GCs [Fe/H]=$-$2.3. We take advantage synthetic spectra isochrones that account for chemical composition to identify separate distinct stellar GCs. derived high-precision...
Recent work with JWST has demonstrated its capability to identify and chemically characterize multiple populations in globular clusters down the H-burning limit. In this study, we explore kinematics of cluster 47 Tucanae by combining data from JWST, HST, Gaia. We analyzed velocity dispersion anisotropy profiles center out $\sim$10$R_h$. Our findings indicate that while 1G stars are isotropic, 2G significantly radially anisotropic. These results align predictions simulations dynamical...
Abstract Wide-field photometry of Galactic globular clusters (GCs) has been investigated to overcome limitations from the small field view Hubble Space Telescope in study multiple populations. In particular, “chromosome maps” (ChMs) built with ground-based were constructed identify first- and second-generation (1G 2G) stars over wide view. The ChMs allow us derive fraction distinct populations an analyzed We present here radial distribution 2G 29 GCs. distributions show that all GCs have...
The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters is providing a major breakthrough in our knowledge globular clusters (GCs) and their stellar populations. Among the main results, we discovered that all studied GCs host two discrete groups consisting first generation (1G) second (2G) stars. We exploit multiwavelength photometry from this project to investigate, for time, Red Giant Branch Bump (RGBB) generations large sample GCs. identified, with high statistical...
Recent work revealed that both the helium variation within globular clusters (GCs) and relative numbers of first second-generation stars (1G, 2G) depend on mass host cluster. Precise determination internal variations fraction 1G are crucial constraints to formation scenarios multiple populations (MPs). We exploit multi-band Hubble Space Telescope photometry investigate MPs in NGC 2419, which is one most-massive distant GCs Galaxy, almost isolated from its tidal influence. find hosts ~37%...
Abstract Studies based on Hubble Space Telescope ( HST ) photometry in F275W, F336W, and F438W have shown that the incidence complexity of multiple populations (MPs) globular clusters (GCs) depend cluster mass. This result, however, is nearby, low-reddening Galactic GCs, for which we can obtain accurate F275W photometry. In this work, exploit F438W, F814W to characterize MPs 68 extragalactic GCs by using pseudocolor C F336W,F438W,F814W , more efficient terms observation time than...
Hubble Space Telescope (HST) photometry is providing an extensive analysis of globular clusters (GCs). In particular, the pseudo two-colour diagram dubbed 'chromosome map (ChM)' allowed to detect and characterize their multiple populations with unprecedented detail. The main limitation these studies small field view HST, which makes it challenging investigate some important aspects populations, such as spatial distributions internal kinematics in outermost cluster regions. To overcome this...
The Hubble Space Telescope (HST) UV Legacy Survey of Galactic Globular Clusters (GCs) has investigated multiple stellar populations by means the "chromosome map" (ChM) diagnostic tool that maximises separation between stars with different chemical composition. One most challenging features revealed ChMs analysis is apparent inhomogeneity among belonging to first population, a phenomenon largely attributed He variations. However, this explanation not supported uniformity in p-capture elements...