相关论文: Investigating point sources in MWC 758 with SPHERE
Combining 3D smoothed-particle hydrodynamics and Monte Carlo radiative transfer calculations, we examine the morphology of spiral density waves induced by gravitational instability (GI) in protoplanetary disks, as they would appear in…
Understanding the diversity of planets requires to study the morphology and the physical conditions in the protoplanetary disks in which they form. We observed and spatially resolved the disk around the ~10 Myr old protoplanetary disk HD…
Spiral arm spurs are prominent features that have been observed in extinction and 8$\mu$m emission in nearby galaxies. In order to understand their molecular gas properties, we used the Owens Valley Radio Observatory to map the CO(J=1--0)…
Aside from the grand-design stellar spirals appearing in the disk of M81, a pair of stellar spiral arms situated well inside the bright bulge of M81 has been recently discovered by Kendall et al. (2008). The seemingly unrelated pairs of…
Context: Because of our viewing point within the Galactic disc, it is extremely difficult to observe the spiral structure of the Milky Way. Aims: To clarify the structure of the Galaxy by re-examination of gas distributions and data from…
Observations of line emission from water masers near the center of the galaxy NGC 4258 have recently provided compelling evidence for rotating disk of gas, viewed nearly edge-on, surrounding a massive black hole (Miyoshi etal. 1995). We…
Direct imaging observations have revealed spiral structures in protoplanetary disks. Previous studies have suggested that planet-induced spiral arms cannot explain some of these spiral patterns, due to the large pitch angle and high…
Observing dynamical interactions between planets and disks is key to understanding their formation and evolution. Two protoplanets have recently been discovered within PDS 70's protoplanetary disk, along with an arm-like structure towards…
We test whether the spiral patterns apparent in many large disk galaxies should be thought of as dynamical features that are stationary in a co-rotating frame for > t_{dyn}, as implied by the density wave approach for explaining spiral…
We have imaged a sample of 20 face-on spiral galaxies in H\alpha and in the near-IR K-band (2.2 microns), in order to determine the location and strength of star formation with respect to perturbations in the old stellar population. We…
Spiral density wave theory attempts to describe the spiral pattern in spiral galaxies in terms of a long-lived wave structure with a constant pattern speed in order to avoid the winding dilemma. The pattern is consequently a rigidly…
Protoplanetary disks around young stars harbor many structures related to planetary formation. Of particular interest, spiral patterns were discovered among several of these disks and are expected to be the sign of gravitational…
Recently, high angular resolution imaging instruments such as SPHERE and GPI have discovered many spiral-arm-like features in near-infrared scattered light images of protoplanetary disks. Theory and simulations have suggested that these…
We run N-body smoothed particle hydrodynamics (SPH) simulations of a Milky Way sized galaxy. The code takes into account hydrodynamics, self-gravity, star formation, supernova and stellar wind feedback, radiative cooling and metal…
We have imaged a sample of 20 spiral galaxies in H$\alpha$ and in the near-infrared K band (2.2 um), in order to determine the location and strength of star formation in these objects with respect to perturbations in the old stellar…
We test the influence of spiral arms on the star formation activity of disk galaxies by constructing and fitting multi-wavelength SEDs for the two nearby spiral galaxies NGC 628 and NGC 4321, at a spatial scale of 1-1.5kpc scale. Recent…
Context. Planet formation is expected to take place in the first million years of a planetary system through various processes, which remain to be tested through observations. Aims. With the recent discovery, using ALMA, of two gaseous…
We present trigonometric parallax and proper motion measurements toward 22 GHz water and 6.7 GHz methanol masers in 16 high-mass star-forming regions. These sources are all located in the Scutum spiral arm of the Milky Way. The observations…
Spiral galaxies are observed to exhibit a range of morphologies, in particular in the shape of spiral arms. A key diagnostic parameter is the pitch angle, which describes how tightly wound the spiral arms are. Observationally and…
We describe an imaging method that makes use of interference filters to provide integrated stellar spectral indices for spiral disks to faint surface brightness limits. We use filters with bandpasses ~60A FWHM, centered on the Mg and Fe…