Related papers: Limits on iron-dominated fallback disk in SN 1987A
We describe calculations for the formation of icy planets and debris disks at 30-150 AU around 1-3 solar mass stars. Debris disk formation coincides with the formation of planetary systems. As protoplanets grow, they stir leftover…
A radiation-driven disk wind model is proposed that offers great promise of explaining the extreme mass loss signatures of massive young stellar objects (the BN-type objects and more luminous Herbig Be stars). It is argued that the dense…
Petrucci et al. (2002; hereafter P02) have reported extraordinary behaviour of the iron K alpha line in the type 1 AGN Mrk 841. At the XMM-Newton/EPIC resolution, a narrow line was observed in a short observation, which then apparently…
The nature of the energy source powering anomalous X-ray pulsars is uncertain. Proposed scenarios involve either an ultramagnetized neutron star, or accretion onto a neutron star. We consider the accretion model proposed recently by…
We report the appearance of a new radio source at a projected offset of 460 pc from the nucleus of Cygnus A. The flux density of the source (which we designate Cygnus A-2) rose from an upper limit of <0.5 mJy in 1989 to 4 mJy in 2016…
We report the discovery of a rapidly rotating disk in a K-selected galaxy at z=1.34. Spatially resolved kinematics are determined from deep, moderate resolution Keck spectroscopy covering the redshifted [OII] 3727 line. A conservative…
We show that the disruption of a star by a 10^6 solar mass black hole in a galactic nucleus could under favorable circumstances produce an optically-thick envelope that radiates with a thermal spectrum at the Eddington limit, 10^{44} erg/s,…
We report the results of a sensitive K-band survey of Herbig Ae/Be disk sizes using the 85-m baseline Keck Interferometer. Targets were chosen to span the maximum range of stellar properties to probe the disk size dependence on luminosity…
The surface flux (and the corresponding observed flux) of a geometrically thick ``funnel'' shaped disk is computed taking into account the radiation impinging on the surface from other parts of the disk. It is found that the ratio of the…
We present 4.5, 8, and 16um photometry from the Spitzer Space Telescope for 204 stars in the Upper Scorpius OB Association. The data are used to investigate the frequency and properties of circumstellar disks around stars with masses…
The Ultra Luminous X-ray Sources (ULXs) are unique in exhibiting moderately bright X-ray luminosities, $L_{\rm x} \sim 10^{38-40} {\rm erg~s^{-1}}$, and relatively high blackbody temperatures, $\Tin \sim 1.0-2.0 {\rm keV}$. From the…
Recent sub-arcsecond resolution surveys of the dust continuum emission from nearby protoplanetary disks showed a strong correlation between the sizes and luminosities of the disks. We aim to explain the origin of the (sub-)millimeter…
We present HST/WFPC2, GALEX and Chandra observations of the position of the type Ia supernova SN2007sr in the Antennae galaxies, taken before the explosion. No source is found in any of the observations, allowing us to put interesting…
We present sub-arcsecond thermal infrared imaging of HD 98800, a young quadruple system composed of a pair of low-mass spectroscopic binaries separated by 0.8'' (38 AU), each with a K-dwarf primary. Images at wavelengths ranging from 5 to…
The presence of optical synchrotron jets in radio galaxies is relatively rare. Here, we show that of the nearest five FR-I 3CR radio galaxies showing optical jets, {\it four} show evidence for almost circular, presumably face-on, dust…
SN 1987A provides a unique opportunity to study the evolution of a supernova from explosion into very late phases. Due to the rich chemical structure, the multitude of physical process involved, and extensive radiative transfer effects,…
We present spatially resolved observations of the canonical transition disk object TW Hya at 8.74 {\mu}m, 11.66 {\mu}m, and 18.30 {\mu}m, obtained with the T-ReCS instrument on the Gemini telescope. These observations are a result of a…
Accurate disk mass measurements are necessary to constrain disk evolution and the timescale of planet formation, but such measurements are difficult to make and are very dependent on assumptions. Here we look at the assumption that the disk…
We have assembled new Spitzer Space Telescope Infrared Array Camera observations of the mysterious binary star Epsilon Aurigae, along with archival far-ultraviolet to mid-infrared data, to form an unprecedented spectral energy distribution…
We present subarcsecond-resolution mid-infrared images of the debris disk surrounding the 230 Myr- old A star Zeta Lep. Our data obtained with T-ReCS at Gemini South show the source to be unresolved at 10.4 microns but clearly extended at…