Search Publications
Astrometric star-cluster membership probability: application to the case of M 37 with Gaia EDR3
Bedin, L. R.; Griggio, M.
In this work, starting from the well-accepted relations in literature, we introduce a new formalism to compute the astrometric membership probabilities for sources in star clusters, and we provide an application to the case of the open cluster M 37. The novelty of our approach is a refined - and magnitude-dependent - modelling of the parallax dist…
Detection of 7Be II in the Small Magellanic Cloud
Izzo, Luca; Selvelli, Pierluigi; Della Valle, Massimo +8 more
We analyse high-resolution spectra of two classical novae that exploded in the Small Magellanic Cloud (SMC). 7Be II resonance transitions are detected in both ASASSN-19qv and ASASSN-20ni novae. This is the first detection outside the Galaxy and confirms that thermo-nuclear runaway reactions, leading to the 7Be formation, are …
Identifying the population of stable ν6 resonant asteroids using large data bases
Carruba, V.; Aljbaae, S.; Domingos, R. C. +2 more
Large observational surveys, like those that will be conducted at the Vera C. Rubin Observatory, are expected to discover up to one million new asteroids in the first year of operation. This will more than double the data base of known asteroids. New methods will be needed to handle the large influx of data. Here, we tested some of these new appro…
Dust grain size evolution in local galaxies: a comparison between observations and simulations
Saintonge, A.; De Looze, I.; Smith, M. W. L. +13 more
The evolution of the dust grain size distribution has been studied in recent years with great detail in cosmological hydrodynamical simulations taking into account all the channels under which dust evolves in the interstellar medium. We present a systematic analysis of the observed spectral energy distribution of a large sample of galaxies in the …
Long-term photometric monitoring and spectroscopy of the white dwarf pulsar AR Scorpii
Dhillon, V. S.; Pelisoli, Ingrid; Breedt, E. +14 more
AR Scorpii (AR Sco) is the only radio-pulsing white dwarf known to date. It shows a broad-band spectrum extending from radio to X-rays whose luminosity cannot be explained by thermal emission from the system components alone, and is instead explained through synchrotron emission powered by the spin-down of the white dwarf. We analysed NTT/ULTRACAM…
Evidence for C and Mg variations in the GD-1 stellar stream
Balbinot, Eduardo; Cabrera-Ziri, Ivan; Lardo, Carmela
Dynamically cold stellar streams are the relics left over from globular cluster dissolution. These relics offer a unique insight into a now fully disrupted population of ancient clusters in our Galaxy. Using a combination of Gaia eDR3 proper motions, optical and near-UV colours, we select a sample of likely Red Giant Branch stars from the GD-1 str…
Model-independent redshift estimation of BL Lac objects through very-high-energy observations
Bhatt, Nilay; Malik, Zahoor; Sahayanathan, Sunder +3 more
The very-high-energy (VHE) gamma-ray spectral indices of blazars show a strong correlation with the source redshift. The absence of any such correlation in low-energy gamma-rays and X-rays indicates the presence of extragalactic background light (EBL)-induced absorption of VHE gamma-rays. By employing a linear regression analysis, this observation…
The protoplanetary disc around HD 169142: circumstellar or circumbinary?
Pinte, C.; Ménard, F.; Bayo, A. +12 more
Stellar binaries represent a substantial fraction of stellar systems, especially among young stellar objects. Accordingly, binaries play an important role in setting the architecture of a large number of protoplanetary discs. Binaries in coplanar and polar orientations with respect to the circumbinary disc are stable configurations and could induc…
Optical counterparts of ULXs in NGC 1672
Akyuz, A.; Allak, S.; Sonbas, E. +1 more
In this work, we deploy archival data from Hubble Space Telescope, Chandra, XMM-Newton, and Swift-XRT, to probe the nature of nine candidate ultraluminous X-ray sources (ULXs) in NGC 1672. Specifically, our study focuses on using the precise source positions obtained via improved astrometry based on Chandra and Hubble Space Telescope observations …
A multi-wavelength view of distinct accretion regimes in the pulsating ultraluminous X-ray source NGC 1313 X-2
Done, C.; Kaaret, P.; Soria, R. +7 more
NGC 1313 X-2 is one of the few known pulsating ultraluminous X-ray sources (PULXs), and so is thought to contain a neutron star that accretes at highly super-Eddington rates. However, the physics of this accretion remains to be determined. Here, we report the results of two simultaneous XMM-Newton and HST observations of this PULX taken to observe…