相关论文: A refurbished convergent point method for finding …
New estimate of the distances of 36 nearby galaxies is presented. It is based on the calibration of the V- and I-band Period-Lumi- nosity relations for galactic Cepheids measured by the HIPPARCOS mission. The distance moduli are obtained in…
Long-period companions are detected and characterized thanks to long-baseline radial velocity surveys. Combining Doppler time-series with astrometry, and in particular with proper motion anomalies technique, it is possible to put strong…
Galaxy groups are essential for studying the distribution of matter on a large scale in redshift surveys and for deciphering the link between galaxy traits and their associated halos. In this work, we propose a widely applicable method for…
Mass ratios of widely separated, long-period, resolved binary stars can be directly estimated from the available data in major space astrometry catalogs, such as the ESA's Hipparcos and Gaia mission results. The method is based on the…
Aims. We are searching for new open clusters or moving groups in the Solar neighbourhood. Methods. We used the Gaia-TGAS catalogue, cut it into narrow proper motion and parallax slices and searched for significant spatial over-densities of…
We prove the existence of the old and metal-rich moving group HR1614. This is done using the new Hipparcos parallaxes in combination with metallicities derived from Stromgren photometry, supported by dynamical simulations of the evolution…
Cosmic filaments are the channel through which galaxy groups assemble their mass. Cosmic connectivity, namely the number of filaments connected to a given group, is therefore expected to be an important ingredient in shaping group…
We analyze 9 open clusters with ages in the range 70 Myr to 3.2 Gyr using UCAC2 proper motion data and 2MASS photometry. For each cluster we consider the projected velocity distributions in the core and off-core regions separately. In the…
We present a new technique for estimating the distance to young open clusters. The method requires accurate measurement of the axial rotation period of late-type members of the cluster: rotation periods are first combined with projected…
We present a new geometrical method aimed at determining the members of open clusters. The methodology estimates, in an N-dimensional space, the membership probabilities by means of the distances between every star and the cluster central…
At intermediate and high degree $l$, solar p- and f modes can be considered as surface waves. Using variational principle, we derive an integral expression for the group velocities of the surface waves in terms of adiabatic eigenfunctions…
The center of the Milky Way is a unique environment of great astrophysical interest, but its extreme crowding and extinction make it difficult to study. The GALACTICNUCLEUS survey, a high-angular-resolution near-infrared imaging program,…
The Hubble Space Telescope (HST) has proven to be uniquely suited for the measurement of proper motions (PMs) of stars and galaxies in the nearby Universe. Here we summarize the main results and ongoing studies of the HSTPROMO…
A two-dimensional velocity distribution in the UV-plane has been obtained for stars in the solar neighbourhood, using the Hipparcos astrometry for over 4000 survey stars with parallaxes greater than 10 mas and radial velocities found in the…
As a planet transits the face of a star, it accelerates along the line-of-sight. The changing delay in the propagation of photons produces an apparent deceleration of the planet across the sky throughout the transit. This persistent…
Change-points are a routine feature of 'big data' observed in the form of high-dimensional data streams. In many such data streams, the component series possess group structures and it is natural to assume that changes only occur in a small…
We determine here peculiar motion of the Solar system, first time from the $m-z$ Hubble diagram of quasars. Observer's peculiar motion causes a systematic shift in the $m-z$ plane between sources lying along the velocity vector and those in…
Astrometry is one of the oldest branches of astronomy which measures the position, the proper motion and parallax of celestial objects. Following the Hipparcos and Gaia missions that have measured several billions of them using global…
We present a method designed to correct for Lutz-Kelker effects in distance-limited samples. The method allows for the calculation of distances to individual objects and, at the same time, provides a fit to a parameterized, self-consistent…
The recent availability of accurate proper motion catalogs for millions of stars on the sky (e.g. Tycho-2, UCAC) can benefit projects for which age estimates are needed for stars that are plausibly young (<100 Myr-old) and within a few…