Related papers: Collimated Fast Wind in the Pre-Planetary Nebula C…

We conduct numerical simulations of axisymmetrical jets expanding into a spherical AGB slow wind. The three-dimensional flow is simulated with an axially symmetric numerical code. We concentrate on jets that are active for a relatively…

The interaction between the strong winds in stellar colliding-wind binary (CWB) systems produces two shock fronts, delimiting the wind collision region (WCR). There, particles are expected to be accelerated mainly via diffusive shock…

An increasing number of early-type (O and Wolf-Rayet) colliding wind binaries (CWBs) is known to accelerate particles up to relativistic energies. In this context, non-thermal emission processes such as inverse Compton (IC) scattering are…

We follow up on our systematic study of axisymmetric hydrodynamic simulations of protoplanetary nebula. The aim of this work is to generate the atomic analogues of the $\mathrm H_2$ near-infrared models of Paper I with the ZEUS code…

We present JWST observations of the Crab Nebula, the iconic remnant of the historical SN 1054. The observations include NIRCam and MIRI imaging mosaics, plus MIRI/MRS IFU spectra that probe two select locations within the ejecta filaments.…

HFG1 is the first well observed planetary nebula (PN) which reveals a cometary-like structure. Its main morphological features consist of a bow shaped shell, which surrounds the central star, accompanied by a long collimated tail. In this…

For pulsars similar to the one in the Crab Nebula, most of the energy input to the surrounding wind nebula occurs on a timescale of less than 1000 years; during this time, the nebula expands into freely expanding supernova ejecta. On a…

A pulsar wind is a relativistic outflow dominated by Poynting energy at its base. Based on the standard ideal magnetohydrodynamic (MHD) model of pulsar wind nebulae (PWNe) with the ordered magnetic field, the observed slow expansion $v_{\rm…

Pulsar bow-shock nebulae are a class of pulsar wind nebulae (PWNe) that form when the pulsar wind is confined by the ram pressure of the ambient medium, and are usually associated with old pulsars, that have already emerged from the…

We follow up on our (Radhakrishnan & Deshpande, 2001: RD01) radically different interpretation of the observed structures and morphologies in the x-ray observations of the nebulae around young pulsars (PWNe). In our general model for PWNe…

As massive stars evolve, their winds change. This causes a series of hydrodynamical interactions in the surrounding medium. Whenever a fast wind follows a slow wind phase, the fast wind sweeps up the slow wind in a shell, which can be…

We are developing a project aimed at studying the physical properties, origin and evolution of low-ionization structures in planetary nebulae. Within this project we have identified a number of pairs of highly collimated low-ionization…

The detection of NaCl at large radii in the Egg Nebula, CRL 2688, requires densities of 10^7 - 10^8 cm^-3 in a thick shell of r ~ a few X 10^17 cm. To explain these results, a mechanism is needed for producing high densities at a…

The Crab Nebula is well-described at optical wavelengths and above by a steady-state magnetohydrodynamic model due to Kennel and Coroniti (1984). Can this class of model describe other pulsar-wind nebulae? I exhibit simple generalizations…

I review some open questions and other aspects concerning the shaping of planetary nebulae (PNs) and related objects. I attribute the non-spherical structures of PNs to binary companions, stellar or substellar. I emphasize the role of jets…

I propose a scenario to account for the fast polar outflow detected to be blown by Eta Carinae in 2000. The scenario accounts also for the lack of this flow in 1998 and 1999. The scenario is based on the binary nature of Eta Carinae. The…

We investigate the velocity structure of nebular gas in the central galaxies of four clusters: Abell 1835, PKS 0745-191, Abell 262, and RXJ0820.9+0752, using data from the Keck Cosmic Web Imager (KCWI). Velocity structure functions (VSFs)…

We present the first part of an investigation on the planetary nebula (PN) PC 22 which focuses on the use of deep imaging and high resolution echelle spectroscopy to perform a detailed morpho-kinematical analysis. PC 22 is revealed to be a…

We have carried out continuum and line polarisation observations of two Proto-planetary nebulae (PPNe), CRL 618 and OH 231.8+4.2, using the Submillimeter Array (SMA) in its compact configuration. The frequency range of observations, 330-345…

Radio emission models of colliding wind binaries (CWBs) have been discussed by Dougherty et al. (2003). We extend these models by considering the temporal and spatial evolution of the energy distribution of relativistic electrons as they…