相关论文: Nomads of the Galaxy
We have explored a method for finding giant planets in the outer Solar System by detecting their thermal emission and proper motion between two far-infrared all-sky surveys separated by 23.4 years, taken with the InfraRed Astronomical…
CONTEXT. Massive stars have high-multiplicity fractions, and many of them have still undetected components, thus hampering the study of their properties. AIMS. I study a sample of massive stars with high angular resolution to better…
Hubble Space Telescope Advanced Cameras for Surveys has been used to determine accurate distances for 20 galaxies from measurements of the luminosity of the brightest red giant branch stars. Five associations of dwarf galaxies that had…
Galaxy sizes and their evolution over cosmic time have been studied for decades and serve as key tests of galaxy formation models. However, at $z\gtrsim1$ these studies have been limited by a lack of deep, high-resolution rest-frame…
The Galaxy appears to be richer in young, massive stellar clusters than previously known, due to advances in infrared surveys which have uncovered deeply embedded regions of star formation. Young, massive clusters can significantly impact…
A radio-based search for strong gravitational lensing, with image separations in the range 160-300 milliarcsec (mas), has yielded a null result for a sample of 1665 sources (Augusto, Wilkinson & Browne 1998) whose mean redshift is estimated…
The vast diversity of planetary systems detected to date is defying our capability of understanding their formation and evolution. Well-defined volume-limited surveys are the best tool at our disposal to tackle the problem, via the…
We present the discovery of a substellar companion to the primary host lens in the microlensing event MOA-2012-BLG-006. The companion-to-host mass ratio is 0.016, corresponding to a companion mass of $\approx8~M_{\rm Jup} (M_*/0.5M_\odot)$.…
We propose that luminous transients, including novae and supernovae, can be used to detect the faintest galaxies in the universe. Beyond a few Mpc, dwarf galaxies with stellar masses $<10^6 M_{\odot}$ will likely be too faint and/or too low…
(Abridged) The solar system gas giant planets are oblate due to their rapid rotation. A measurement of the planet's projected oblateness would constrain the planet's rotational period. Planets that are synchronously rotating with their…
We use a sample of Milky Way (MW) analogs for which we have stellar and disk gas mass measurements, published measurements of halo gas masses of the MW and of similar galaxies, and the well-established value of the cosmological baryon…
Most young low-mass stars are born as binary systems, and circumstellar disks have recently been observed around the individual components of proto-binary systems (e.g. L1551-IRS5). Thus planets and planetary systems are likely to form…
Recently the Polish-American collaboration OGLE has reported the observation of four possible microlensing events by monitoring, over several months, the brightness of millions of stars in the region of the galactic bulge. If these events…
The merging history of galaxies can be traced with studies of dynamically close pairs. These consist of a massive primary galaxy and a less massive secondary (or satellite) galaxy. The study of the stellar populations of secondary (lower…
We study the populations of stellar clumps in three high-redshift galaxies, at z=4.92, 4.88 and 4.03, gravitationally lensed by the foreground galaxy clusters MS1358, RCS0224 and MACS0940, respectively. The lensed galaxies consist of…
In the light of new full-sky surveys, many attempts of creating a consistent Galactic model were made. The main interest is to estimate the still poorly understood dark matter content. However, the results vary depending on methodology,…
Direct imaging has led to the discovery of several giant planet and brown dwarf companions. These imaged companions populate a mass, separation and age domain (mass>1MJup, orbits>5AU, age<1Gyr) quite distinct from the one occupied by…
We use seven year's worth of observations from the Catalina Sky Survey and the Siding Spring Survey covering most of the northern and southern hemisphere at galactic latitudes higher than 20 degrees to search for serendipitously imaged…
Astronomical objects in our universe that are too faint to be directly detectable exist and are important - an obvious example being dark matter. The same can also apply to very faint baryonic objects, such as low luminosity dwarf galaxies…
Microlensing surveys suggest the presence of a surprisingly large population of free-floating planets, with a rate of about two Neptunes per star. The origin of such objects is not known, neither do we know if they are truly unbound or are…