相关论文: Combining and comparing astrometric data from diff…

The GPS1 catalog was released in 2017. It delivered precise proper motions for around 350 million sources across three-fourths of the sky down to a magnitude of $r\sim20$\,mag. In this study, we present GPS1+ the extension GPS1 catalog down…

Future missions, including the Habitable Worlds Observatory, will aim to image Earth-like exoplanets around Sun-like stars in reflected light. Determining whether an exoplanet is in the habitable zone of its star may be difficult in…

With the aim of paving the road for future accurate astrometry with MICADO at the European-ELT, we performed an astrometric study using two different but complementary approaches to investigate two critical components that contribute to the…

Although the Gaia catalogue on its own will be a very powerful tool, it is the combination of this highly accurate archive with other archives that will truly open up amazing possibilities for astronomical research. The advanced…

Accurate positional measurements of planets and satellites are used to improve our knowledge of their dynamics and to infer the accuracy of planet and satellite ephemerides. In the framework of the FP7 ESPaCE project, we provide the…

Context. Planetary nebulae (PNe) are a brief but important phase of stellar evolution. The study of Galactic PNe has historically been hampered by uncertain distances, but the parallaxes of PN central stars (CSPNe) measured by Gaia are…

We provide a scheme to correct asteroid astrometric observations for star catalog systematic errors due to inaccurate star positions and proper motions. As reference we select the most accurate stars in the PPMXL catalog, i.e., those based…

Gaia's very accurate astrometric measurements will allow the International Celestial Reference Frame (ICRF) to be improved by a few orders of magnitude in the optical. Several sets of quasars are used to define a kinematically stable…

Astrometric jitter noise arises when starspots on a rotating stellar surface move in and out of view, shifting the photocenter. This noise may limit our ability to detect and weigh small, sub-Neptune-sized planets around active stars. By…

The detectors designed for Gaia, the next ESA space astrometry mission to be launched in 2011, will allow to observe repeatedly stars very close to Jupiter's limb. This will open a unique opportunity to test General Relativity by performing…

The Hubble Space Telescope recently celebrated 25 years of operation. Some of the first images of extragalactic optical jets were taken by HST in the mid-1990s; with time baselines on the order of 20 years and state-of-the-art astrometry…

We present a hierarchical Bayesian pipeline, BP3M, that measures positions, parallaxes, and proper motions (PMs) for cross-matched sources between Hubble~Space~Telescope (HST) images and Gaia -- even for sparse fields ($N_*<10$ per image)…

We present constraints on the presence of substellar companions to the nearby ($d\sim7.6$ pc), young ($440\pm40$ Myr) K4Ve star TW Piscis Austrini, the wide ($\sim$0.3 pc) companion to the A4V star Fomalhaut. We combined absolute astrometry…

A subset of 51 Hipparcos astrometric binaries among FG dwarfs within 67pc has been surveyed with the NICI adaptive optics system at Gemini-S, directly resolving for the first time 17 sub-arcsecond companions and 7 wider ones. Using these…

With the application of advanced astronomical technologies, equipments and methods all over the world, astronomy covers from radio, infrared, visible light, ultraviolet, X-ray and gamma ray band, and enters into the era of full wavelength…

The Space Interferometry Mission (SIM), with its launch date planned for 2005, has as its goal astrometry with ~ 1 micro-arcsecond accuracy for stars as faint as 20th mag. If the SIM lives to expectations it can be used to measure…

Building on previous Bayesian approaches, we introduce a novel formulation of probabilistic cross-identification, where detections are directly associated to (hypothesized) astronomical objects in a globally optimal way. We show that this…

A new all-sky visible and Near-InfraRed (NIR) space astrometry mission with a wavelength cutoff in the K-band is not just focused on a single or small number of key science cases. Instead, it is extremely broad, answering key science…

Given the extreme accuracy of modern space astrometry, a precise relativistic modeling of observations is required. Moreover, the availability of several models formulated in different and independent ways is a security against the presence…

(abridged) The Hundred-Thousand-Proper-Motion (HTPM) project will determine the proper motions of ~113500 stars using a 23-year baseline. The proper motions will use the Hipparcos data, with epoch 1991.25, as first epoch and the first…