Massive stars inject energy into the surrounding medium and form shell structures. Bubbles are blown by fast stellar winds from individual massive stars, while superbubbles are blown by fast stellar winds and supernova explosions from groups of massive stars. Bubbles and superbubbles share a similar overall structure: a swept-up dense shell with an interior filled by low-density hot gas. Physical properties of a bubble/superbubble can be affected by magnetic field, thermal conduction, turbulent mixing, inhomogeneous ambient medium, etc. I will review recent progresses on observations and compare them to theoretical expectations for (1) swept- up dense shells, (2) hot interiors, and (3) interface between a dense shell and its interior hot gas.

The cataclysmic events known as supernovae enrich their surroundings with heavy elements synthesized in the explosions. These fast-moving stellar ejecta drive a blast wave that sweeps up the circumstellar material and accelerates particles to extremely high energies. As the blast wave decelerates, a supersonic pressure wave is driven back through the ejecta, heating them to temperatures of millions of degrees. Studies of the X-ray emission from these supernova remnants thus provide information on the properties of the explosion, the composition of the ejecta material, and the process of particle acceleration. In this tutorial I will review the basic structure and evolution of supernova remnants and discuss how current observations are providing important constraints the nature of the explosions, the properties of the progenitors, and the environments in which these remnants evolve.

Galaxies are made up of stars, gas and dust. Active galaxies have these same basic ingredients, but in addition they have a supermassive black hole (SMBH) located at their dynamical centre. The mass of this central black hole can range from 100,000 times (the lower mass limit is uncertain) up to a billion solar masses. It is the influence of this black hole on its local and galactic environment that produce the observed properties of an active galactic nucleus (AGN). The fundamental power source is accretion of material onto the SMBH. Some galaxies may have a SMBH, but it is not accreting material, these are called "inactive" or "normal galaxies." In cases of significant accretion rate (Mdot), an active galaxy can be distinguished from a normal, or even a starforming galaxy, by means of its multi- frequency spectral energy distribution, and also from its emission line spectrum. In this lecture I will identify the various signatures of non-stellar activity that are used to classify a galaxy as active. Some key characteristics are; a very high bolometric luminosity, variability of the continuum emission, and emission line ratios and ionisation species that cannot be produced by only a stellar population. Unfortunately there are a large number of different names given to various classes of AGN. But these differences can mostly be understood in terms of basic parameters eg. black hole mass, accretion rate and the efficiency of roduction of radiation, the geometry of the nucleus and the angle at which we view it. The influence of an active nucleus can extend from the immediate environment of the black hole at a few gravitational radii, out to 100's of kiloparsecs in the case of powerful radio galaxies. Understanding the physics of AGN is increasingly important because of their role in galaxy evolution and feedback.

Time has come. It is your first talk at a meeting, not in your native language, and 100 pairs of eyes much smarter than you are staring right at you. STREEEESSSSSS!! PAAAANIC!!! But hold on a minute: Most of the audience are not native English speakers either, and you ARE the world's expert on the topic of your talk, however small, else you would not be on the program. So relax, and remember that you are more likely to err on the side of giving a talk that is too difficult for your audience in substance and language than too easy. You can already go from a below-average talk by obeying a few simple rules about what to do and what to avoid, and with a few extras, before you know it you have a good talk. I hope that some of the recommendations in my talk will help you get there.

Observational and theoretical evidence suggests that binary interactions may play a substantial and perhaps necessary role in post-main sequence evolution for low- mass stars (< 8 M_sun). In this talk, I highlight one particular interaction in which close companions are immersed in a common envelope. The resulting in- spiral can influence mass-loss and lead to large-scale magnetic field amplification. In contrast to binary systems, a weaker dynamo (a la the Sun) may be operating in isolated RGB/AGB stars. Observationally, isotopic abundance measurements require that extensive, slow mixing transports material from the hydrogen-burning shell to the convective envelope (so called Cool Bottom Processing). I discuss whether buoyant magnetic flux tubes amplified in the stellar interior can supply the necessary CBP transport rates to match observations.

Gamma-ray bursts result from the death of very massive stars; unlike in supernovae, a few Earth masses of material is ejected into space with almost the speed of light, causing the special phenomena that make up a GRB. I will discuss how we deduce these facts from the basic observations, an our current best thinking of what makes GRB explosions so different from supernnovae.

According to popular progenitor models of gamma-ray bursts, twin jets should be launched by the central engine, with a preceding jet moving toward the observer and a receding jet moving backwardly. However, in calculating the afterglows, usually only the emission from the preceding jet is considered. Here we present a detailed numerical study on the afterglow from the receding jet. Our calculation is based on a generic dynamical description, and includes some delicate ingredients such as the effect of the equal arrival time surface. It is found that the emission from the receding jet is generally rather weak. In radio bands, it usually peaks at a time of $t \geq 1000$ d, with the peak flux nearly 4 magnitudes lower than the peak flux of the receding jet. Also, it usually manifests as a short plateau in the total afterglow light curve, but not as an obvious rebrightening as once expected. In optical bands, the contribution from the receding jet is even weaker, with the peak flux being $\sim 8$ magnitudes lower than the peak flux of the preceding jet. We thus argue that the emission from the receding jet is very difficult to detect. However, in some special cases, i.e., when the circum-burst medium density is very high, or if the parameters of the receding jet is quite different from those of the preceding jet, the emission from the receding jet can be significantly enhanced and may still emerge as a marked rebrightening. We suggest that the search for receding jet emission should mostly concentrate on nearby gamma-ray bursts, and the observation campaign should last for at least several hundred days for each event.

The radiation origin of GRB prompt emission is still an open question. Recent Fermi observations of high-energy gamma-ray emission from GRB 080916C shows that its spectrum is consistent with a single component from MeV to tens of GeV, suggesting one dominant single emission mechanism at work in the whole energy range. We study what constraint this has posed on GRB emission mechanism and find that synchrotron origin is favored.

The combination of a long duration and the absence of any accompanying supernova clearly shows that GRB 060614 can not be grouped into the two conventional classes of gamma-ray bursts, i.e. the long/soft bursts deemed to be collapsars and the short/hard bursts deemed to be merging binary compact stars. A new progenitor model is required for this anomalous gamma-ray burst. We propose that GRB 060614 might be produced through the tidal disruption of a star by an intermediate mass black hole. In this scenario, the long duration and the lack of any associated supernova are naturally expected. The theoretical energy output is also consistent with observations. The observed 9- s periodicity in the $\gamma$-ray light curve of GRB 060614 can also be satisfactorily explained.

I will discuss hydrodynamical models for the Cassiopeia A supernova remnant and its observed jet / counter-jet system. Though this supernova remnant is young (330 yr) and located in our own galaxy, the supernova was not observed and the type of star that exploded has long been unknown. We model the circumstellar medium and the subsequent evolution of the supernova remnant, and show how the appearance of jets in the supernova remnant can be used as a diagnostic to determine the type of progenitor star.

We present results from a recent campaign to quantify the X-ray morphologies of supernova remnants (SNRs) observed with the Chandra X-ray Telescope. We have applied three mathematical techniques to Chandra ACIS observations of about twenty galactic SNR sources: a power-ratio technique to measure morphological asymmetry, correlation-length analysis to probe chemical segregation, and wavelet-transform analysis (WTA) to quantify X-ray substructure. Detailed comparison between sources provides crucial insights regarding the nature of the explosion, the effects of heating and dense environments, and particle acceleration properties. For each remnant, we have created individual images of observed spectral features (emission lines, thermal and non- thermal emission). Using CLA, we disentangle the thermal and non-thermal emitting regions, and we measure with great accuracy the sizes and locations of thermal and non-thermal clumps with WTA. The non-thermal continuum is located predominantly around the rim of our sources, and it has great excess power at small scales compared to the thermal component. Application of our methods to radio data reveals how the size of non- thermal emitting regions changes as a function of photon energy, which provides crucial insight to understand the magnetic-field properties and particle acceleration mechanisms. Additionally, detailed knowledge of the X-ray line substructure enables much more precise ejecta mass estimates than any previous SNR studies, key to constraining the supernova explosion histories. Generally, this work is a first step to develop a global picture of these varied sources.

Although about half of the Galactic supernova remnants (SNRs) are supposed to be in physical contact with molecular clouds (MCs), only some twenty SNRs are as yet known to interact with their ambient MCs with convincing evidences (most of which are based on the detection of 1720 MHz OH masers). To reveal more evidences of SNR-MC interaction, we are observing, and planning to observe, a sample of SNRs with highly asymmetric morphologies in CO and HCO+ molecular lines. This presentation will focus on the molecular shells discovered in SNRs Kes69 and Kes75. In the both SNRs, blue-shifted broadening in the 12CO (J=1-0) line profiles are found in specific LSR velocities, and molecular arcs/shells are found in the broadened line wings and are coincident with the SNR shells seen in centimeter radio, mid infrared, and X-rays. The line broadening and the morphological coincidence provide convincing evidence of the association of the SNRs with the corresponding MCs. The association leads to a determination of the kinematic distances to the SNRs. The multi-wavelength emissions along the shells can be accounted for by the impact of the SNR shocks on arc-like structures of dense, clumpy molecular gas. Such pre-existing structures are most likely to be parts of the cooled debris of the MC gas swept up by the massive progenitors' stellar winds. Thus we suggest that molecular shells are probably common in a number of SNRs.

We investigate the molecular environment of the semicircular composite supernova remnant (SNR) 3C396 by 13.7m millimeter telescope observation. The 12CO and 13CO millimeter spectroscopic observations toward 3C396 show a cavity at V(LSR) \sim 69km/s, in consistence with the suggestion by Lee et al. (2008, arXiv:0819.0802) based on 13CO data. However, we find the molecular gas distribution at V(LSR) \sim 85km/s can also, and even better, explain the multiwavelength properties of this SNR. Around this LSR velocity, there is a molecular wall in the west, accounting for the bright X-ray, radio, and infrared emission along the western edge. The CO emission fades out from west to east, indicating that the eastern region is of low gas density, accounting for the radio blow-out morphology in the east. In particular, a finger/pillar like molecular cloud is revealed in the southwest, with one end intruding inside the SNR border. The shock interaction with this finger tip can well explain the X-ray and radio enhancement in the SW and some infrared filaments there. The diffuse thermal X-ray emitting gas of the SNR is found to be metal enriched except in the SW enhancement. The favor of the association of this SNR with the 85km/s cloud would suggest the supernova exploded near the edge of the molecular cloud and place 3C396 at a distance of 6.2 kpc (around the tangent point).

We discuss the generic characteristics of stochastic particle acceleration by a fully developed turbulence spectrum and show that resonant interactions of particles with high speed waves dominate the acceleration process. To produce the relativistic electrons inferred from the broadband spectrum of a few well- observed shell-type supernova remnants in the leptonic scenario for the TeV emission, fast mode waves must be excited effectively in the downstream and dominate the turbulence in the subsonic phase. Strong collisionless non- relativistic astrophysical shocks are studied with the assumption of a constant Aflv\'{e}n speed. The energy density of non-thermal electrons is found to be comparable to that of the magnetic field. With reasonable parameters, the model explains observations of shell-type supernova remnants. More detailed studies are warranted to better understand the nature of supernova shocks.

Pulsars typically travel supersonically through the interstellar medium in their late stage of evolution. In such cases, the pulsar outflows are confined by the ram pressure, resulting in bow shock nebulae with long tails. ATCA observations of the bow shock associated with PSR J1509-5850 reveal an exceptionally long tail over 10 pc in radio. Polarization maps at 3 and 6cm indicate a helical magnetic field structure of the tail, providing the first evidence of a pulsar magnetotail.

The ultra-intense magnetic field of magnetars is a mystery in astrophysics. We model the dynamics of collapsing massive progenitor stars with high surface magnetic fields in the framework of a self-similar general polytropic magnetofuild under the self-gravity with quasi-spherical symmetry. With the specification of physical parameters such as mass density, temperature, magnetic field and wind mass loss rate on the progenitor stellar surface and the consideration of a rebound shock breaking through the stellar envelope, we find a compact object (neutron star) left behind at the centre with radius ~ 10^6 cm and a mass ~ 1-3 solar mass. In particular, we find the surface magnetic field of this compact object is ~ 10^{14} - 10^ {15} G, consistent with those of magnetars. The magnetic enhancement factor critically depends on the self-similar scaling index n, which also determines the initial density distribution of the progenitor. We propose that magnetic massive stars as magnetar progenitors based on the dynamic evolution of the core collapse and rebound shock. Our mechanism, which does not require ad hoc dynamo amplification, favours the 'fossil field' scenario of forming magnetars.

We report the observations of a super bubble consists of shocked gas and dust in the tidal-torn region approximately 4kpc to the SE of the starburst galaxy NGC 3077, a member of the M81-M82-NGC3077 triplet. A ring-like structure of thermal emission is seen in all imaging bands of the Spitzer Space Telescope, and coincides with strong radio continuum emission as well as numerous bright HII regions previously found. We have measured the precise velocities of these HII regions, which help to paint a detailed picture of the relationship between the gas/dust of the bubble and young star forming regions in its vicinity.

Non-equilibrium ionization is an important phenomenon related to many astrophysical processes, such as rapid heating or cooling, in which gas may be under-ionized or over-ionized. It is seen in a variety of astrophysical scenarios, from the small scale such as massive star winds, accretion flows in X-ray binaries, stellar cluster winds, shocks in SNR, to the large scale such as galactic superwinds, AGN outflows, and the shock flows in the intergalactic medium. However, current modeling is limited by the equilibrium ionization assumption. I will emphasize the important role of the non- equilibrium ionization in the theoretical modelings for various plasmas. The generalized NEI code will be introduced both for the collisional ionization and photoionization. In addition, I will review the updated atomic database and atomic processes which are important for the non- equilibrium plasma. The applications of our NEI code in accretion disk corona of HerX-1, line diagnostics in SNR N132D, warm-hot intergalactic medium will be presented.

The state transitions of black hole (BH) X-ray binaries are discussed based on the evolution of large-scale magnetic fields, in which the combination of three energy mechanisms are involved: (1) the Blandford-Znajek (BZ) process related to the open field lines connecting a rotating BH with remote astrophysical loads, (2) the magnetic coupling (MC) process related to the closed field lines connecting the BH with its surrounding accretion disk, and (3) the Blandford-Payne (BP) process related to the open field lines connecting the disk with remote astrophysical loads. It turns out that each spectrum state of the BH binaries corresponds to each configuration of magnetic field in BH magnetosphere, and the main characteristics of low/hard (LH) state, hard intermediate (HIM) state, steep power law (SPL) state and thermal–dominant (TD) state are roughly fitted based on the evolution of large-scale magnetic fields associated with disk accretion. Two kinds of the magnetic instabilities are invoked to interpret the transitions from LH to SPL states and from SPL to TD states.

The black hole X-ray transient XTE J1550-564 has undergone a strong outburst in 1998 and two relativistic X-ray jets have been detected years later with the Chandra X-ray observatory; the eastern jet was found previously to have decelerated after its first detection. Here we report a full analysis of the evolution of the western jet; significant deceleration is also detected in the western side. Our analysis indicates that there is a cavity outside the central source and the jets first traveled with constant velocity and then were slowed down by the interactions between the jets and the interstellar medium (ISM). The best fitted radius of the cavity is about 0.31 pc on the eastern side and about 0.44 pc on the western side, and the densities also show asymmetry, of about 0.034/cm^3 on the east to about 0.12/cm^3 on the west. The best fitted magnetic fields on both sides are about 0.5 mG. Similar analysis is also applied to another microquasar system, H 1743-322, and a large scale low density region is also found. Based on these results and the comparison with other microquasar systems, we suggest a generic scenario for microquasar jets, classifying the observed jets into three main categories, with different jet morphologies (and sizes) corresponding to different scales of vacuous environments surrounding them. We also suggest that the accretion disk winds and/or continuous jets may be responsible for creating these cavities. Therefore X-ray jets from microquasars provide us with a promising method of probing the environment of accreting black holes.

We report on a systematical investigation of optical Fe II and Hbeta emission lines in z<0.8 quasars selected from the Sloan Digital Sky Survey. We have developed a detailed line-fitting technique, taking into account the complex continuum and multi-component emission-line spectrum. We find that the majority of quasars show Fe II emission that is redshifted, typically by ~400 km/s, and up to 2000 km/s, with respect to the systemic velocity of the narrow-line region or of the conventional broad-line region as traced by the Hbeta line. Moreover, the line width of Fe II is significantly narrower than that of the broad component of Hbeta. We show that the magnitude of the Fe II redshift correlates inversely with the Eddington ratio, and that there is a tendency for sources with redshifted Fe II emission to show red asymmetry in the Hbeta line. We also find that the profile of Hbeta emission line depends on its line width. The conventional broad Hbeta emission line can be decomposed into two components---one with intermediate velocity width and another with very broad width. The velocity shift and equivalent width of the intermediate-width component do not correlate with those of the very broad component of Hbeta, but its velocity shift and width do resemble Fe II. These characteristics strongly suggest the existence of an intermediate-line region, whose kinematics seems to be dominated by infall, located at the outer portion of the broad-line region, and emitting the major Fe II emission. The velocity of the inflow is determined by the competiton between the gravity of the central black hole and the radiation pressure. Such an inflow is likely to develop from the inner edge of the dusty torus, and connect with the broad line region or accretion disk.

Abstract: We collected almost all of the type II quasars so far discovered. Among them 485 sources have photometric data at JHK bands, mainly from 2MASS observations, 65 sources have IRAS photometric data in at least one of the three IRAS bands at 25, 60 and 100μm, and 15 sources have IRAS photometric data in all three IRAS bands. We find that in nearly half of all type II quasars, both the near and far infrared radiation is dominated by starlight or thermal reprocessing of starlight by dust in the underlying galaxy. The infrared radiation of the other group (slightly over half) is dominated by non-thermal radiation in the near infrared, and mostly in the far infrared also (although there is a mixture particularly for the longer wavelengths). It is proposed that for the later group, hidden broad lines may exist in the infrared. On the basis of our and previous results, we also discuss the possibility that there are two distinct classes of type II quasars: "true" type II quasars without a BLR, and heavily obscured type I quasars, in full analogy with the case for type II Seyferts. No relationships can be found for either the near infrared or the far infrared colors and the redshift. Correlations between absolute magnitude in the near and far infrared with redshift are found, but could be due to a flux limit (Malmquist bias).