New Anglo-Australian Telescope near-infrared and Swedish-ESO Submillimetre Telescope CO obJ p 2 r 1 servations are combined with existing Infrared Space Observatory mid-infrared and Australia Telescope Compact Array centimeter radio continuum observations to examine the protostellar content of the Bok globule BHR 71. Together with observations of Herbig-Haro objects, these data show the followi...

We present evidence that the spectroscopically identified bipolar jets of the pre-main sequence binary KH 15D (P=48.4 d, ǫ ∼0.6, periastron separation ∼18 RA, MA=0.6M⊙, MB=0.7M⊙) are a common product of the whole binary system, rather than being launched from either star individually. They may be launched from the innermost part of the circumbinary disk (CBD) or may result from the merging of t...

Very early optical and near infrared (IR) emission was discovered accompanying the long gamma-ray burst (GRB) 041219a. We show that the optical/IR flash tracking the gamma-ray lightcurve during the prompt emission could be understood as emission from neutron-rich internal shocks, as has been suggested by Fan & Wei. The early Ks-band afterglow lightcurve after the prompt phase could be well-mode...

We have analyzed nearly eight years of MACHO optical photometry of the supersoft X-ray binary RX J0513.9−6951 and derived a revised orbital period and ephemeris. Previously published velocities are reinterpreted using the new ephemeris. We show that the spectroscopic characteristics of the system depend strongly on whether the system is in a high or low optical state. We also discuss the proper...

Very early optical and near-infrared emission was discovered to have accompanied the long gamma-ray burst GRB 041219a. Here we show that the optical-IR flash tracking the gamma-ray light curve during the prompt emission can be understood as emission from neutron-rich internal shocks, as has been suggested by Fan & Wei. The early Ks-band afterglow light curve after the prompt phase can be well m...

Both radiative and mechanical feedback from Active Galactic Nuclei have been found to be important for the evolution of elliptical galaxies. We compute how a shock may be driven from a central black hole into the gaseous envelope of an elliptical galaxy by mechanical as well as radiative feedback (in the form of nuclear winds) using high resolution 1-D hydrodynamical simulations. We calculate t...

The ratio of the Bondi and Jeans lengths is used to develop a cloud-accretion model that describes both an inner Bondi-type regime where gas pressure is balanced by the gravity of a central star and an outer Jeans-type regime where gas pressure is balanced by gas self-gravity. The gas density profile provided by this model makes a smooth transition from a wind-type inner solution to a Bonnor-Eb...

In this paper we present a numerical study of plasma jets produced by intense laser matter interactions. Through this study we hope to better understand astrophysical jets and their recent experimental simulations in the laboratory. We paid special attention to radiation cooling and the interaction of the jet with ambient gas. Four cases are presented in this paper; two of them deal with the pr...

We study the bending of jets in binary stellar systems. A compact companion accretes mass from the slow wind of the mass-losing primary star, forms an accretion disk, and blows two opposite jets. These fast jets are bent by the slow wind. Disregarding the orbital motion, we find the dependence of the bending angle on the properties of the slow wind and the jets. Bending of jets is observed in p...

We present five epochs of simultaneous radio (VLA) and X-ray (Chandra) observations of SS 433, to study the relation between the radio and X-ray emission in the arcsecond-scale jets of the source. We detected X-ray emission from the extended jets in only one of the five epochs of observation, indicating that the X-ray reheating mechanism is transient. The reheating does not correlate with the t...