Observations of young stellar objects, such as classical T Tauri stars (CTTSs), show evidence of accretion disks (ADs), outflows and jets. It is shown that Alfven waves (AWs) are important in all of these phenomena. AWs can be created by turbulence in the AD and magnetosphere of a CTTS. Jets, stellar outflows, and the heating of the central regions of ADs may be due to the damping of AWs. Our r...

Some evolved stars in the pre-planetary nebula phase produce highly-collimated molecular outflows that resemble the accretion-driven jets and outflows from pre-main sequence stars. We show that IRAS 16342-3814 (the Water Fountain Nebula) is such an object and present K-band integral field spectroscopy revealing a fast (> 150 km s) bipolar H2 outflow. The H2 emission is shock excited and may ari...

We present the first images of the pulsar wind nebula (PWN) MSH 15−52 in the hard X-ray band (> ∼8 keV), as measured with the Nuclear Spectroscopic Telescope Array (NuSTAR). Overall, the morphology of the PWN as measured by NuSTAR in the 3–7 keV band is similar to that seen in Chandra high-resolution imaging. However, the spatial extent decreases with energy, which we attribute to synchrotron e...

The detection of inflows at the scale dusty torus and smaller is crucial for investigating process supermassive black hole (SMBH) accretion. However, only a few cases inflowing gas small scales have been reported through redshifted broad absorption lines so far. Here we report nine narrow (NALs) Mg + ions with speeds 1071–1979 km s −1 , which are likely along directions close to axes accretion ...

Radio-loud AGNs can inhabit regions with a very rich ISM. The presence of this rich medium is likely related to the origin and evolution of the host galaxy and of the active nucleus. Recent observations show that a large fraction of radio galaxies contains a significant young stellar population. This supports the idea that mergers are responsible for both the starburst phase and the triggering ...

I propose that the moving ‘wisps’ near the center of the Crab Nebula result from nonlinear KelvinHelmholtz instabilities in the equatorial plane of the shocked pulsar wind. Recent observations suggest that the wisps trace out circular wavefronts in this plane, expanding radially at speeds<∼ c/3. Instabilities could develop if there is sufficient velocity shear between a faster-moving equatorial...

We show that the forward-reverse shocks model (in the ISM case), the late internal shocks model and the early energy injection model are able to power an early X-ray bump in GRB “afterglows”. However, the temporal behaviors of their decline are much different, which in turn provides us a simple but reliable tool to distinguish them. We suggest that the early X-ray bump observed in GRB 011121 co...

We present near-infrared H2, radio CO, and thermal infrared observations of the nearby massive star-forming region Cepheus A (Cep A). From H2 bow shocks arranged along four distinct jet axes, we infer that the massive protostellar source HW2 drives a pulsed, precessing jet that has changed its orientation by about 45 in roughly 104 years. The current HW2 radio jet represents the most recent eve...

We have used the integral field spectrograph OSIRIS and laser guide star adaptive optics at Keck Observatory to obtain high angular resolution (0. 06), moderate spectral resolution (R ≃ 3800) images of the bipolar jet from the Herbig Ae star LkHα 233, seen in near-IR [Fe II] emission at 1.600 & 1.644 μm. This jet is narrow and tightly collimated, with an opening angle of only 9 degrees, and has...

We discuss the dynamics of microquasar jets in the interstellar medium, with specific focus on the effects of the X-ray binaries’ space velocity with respect to the local Galactic standard of rest. We argue that, during late stages in the evolution of large scale radio nebulae around microquasars, the ram pressure of the interstellar medium due to the microquasar’s space velocity becomes import...