Ejecta, Dust, and Synchrotron Radiation in SNR B0540–69.3: A More Crab-Like Remnant than the Crab
We present near- and mid-infrared observations of the pulsar-wind nebula (PWN) SNR B0540?69.3 and its associated supernova remnant made with the Spitzer Space Telescope. We report detections of the PWN with all four IRAC bands, the 24 ?m band of MIPS, and the Infrared Spectrograph (IRS). We find no evidence of IR emission from the X-ray/radio shell surrounding the PWN resulting from the forward shock of the supernova blast wave. The flux of the PWN itself is dominated by synchrotron emission at shorter (IRAC) wavelengths, with a warm dust component longward of 20 ?m. We show that this dust continuum can be explained by a small amount [~ -->(1?3) ? 10?3 -->M?] of dust at a temperature of ~50-65 K, heated by the shock wave generated by the PWN being driven into the inner edge of the ejecta. This is evidently dust synthesized in the supernova. We also report the detection of several lines in the spectrum of the PWN and present kinematic information about the PWN as determined from these lines. Kinematics are consistent with previous optical studies of this object. Line strengths are also broadly consistent with what one expects from optical line strengths. We find that lines arise from slow (~20 km s?1) shocks driven into oxygen-rich clumps in the shell swept up by an iron-nickel bubble, which have a density contrast of ~100-200 relative to the bulk of the ejecta, and that faster shocks (~250 km s?1) in the hydrogen envelope are required to heat dust grains to observed temperatures. We infer from estimates of heavy-element ejecta abundances that the progenitor star was likely in the range of 20-25 -->M?.

title: OBSERVATIONS AND INTERPRETATION OF A LOW CORONAL SHOCK WAVE OBSERVED IN THE EUV BY THE SDO/AIA
abstract: Taking advantage of both the high temporal and spatial resolutions of the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory, we studied a limb coronal shock wave and its associated extreme ultraviolet (EUV) wave that occurred on 2010 June 13. Our main findings are: (1) the shock wave appeared clearly only in the channels centered at 193 angstrom and 211 angstrom as a dome-like enhancement propagating ahead of its associated semi-spherical coronal mass ejection (CME) bubble; (2) the density compression of the shock is 1.56 according to radio data and the temperature of the shock is around 2.8 MK; (3) the shock wave first appeared at 05: 38 UT, 2 minutes after the associated flare has started and 1 minute after its associated CME bubble appeared; (4) the top of the dome-like shock wave set out from about 1.23 R-circle dot and the thickness of the shocked layer is similar to 2 x 10(4) km; (5) the speed of the shock wave is consistent with a slight decrease from about 600 km s(-1) to 550 km s(-1); and (6) the lateral expansion of the shock wave suggests a constant speed around 400 km s(-1), which varies at different heights and directions. Our findings support the view that the coronal shock wave is driven by the CME bubble, and the on-limb EUV wave is consistent with a fast wave or at least includes the fast wave component.

title: A DETAILED ANALYSIS OF A CYGNUS LOOP SHOCK-CLOUD INTERACTION
abstract: The XA region of the Cygnus Loop is a complex zone of radiative and nonradiatve shocks interacting with interstellar clouds. We combine five far ultraviolet spectral observations from the Hopkins Ultraviolet Telescope (HUT), a grid of 24 IUE spectra, and a high-resolution long-slit Hα spectrum to study the spatial emission line variations across the region. These spectral data are placed in context using ground-based optical emission-line images of the region and a far-UV image obtained by the Ultraviolet Imaging Telescope (UIT). The presence of high-ionization species (O VI, N V, and C IV) indicates a shock velocity near 170 km s-1 while other diagnostics indicate vsh ≈ 140 km s-1. It is likely that a large range of shock velocities may exist at a spatial scale smaller than we are able to resolve. By comparing C IV λ1550, C III λ977, and C III] λ1909, we explore resonance scattering across the region. We find that a significant column depth is present at all positions, including those not near bright optical or UV filaments. Analysis of the O VI doublet ratio suggests an average optical depth of about unity in that ion, while flux measurements of [Si VIII] λ1443 suggest a hot component in the region at just below 106 K. Given the brightness of the O VI emission and the age of the interaction, we rule out the mixing-layer interpretation of the UV emission. Furthermore, we formulate a picture of the XA region as that of an encounter of the blast wave with a finger of dense gas protruding inward from the pre-supernova cavity.

title: Deep Chandra Observations of the Crab-like Pulsar Wind Nebula G54.1+0.3 and Spitzer Spectroscopy of the Associated Infrared Shell
abstract: G54.1+0.3 is a young pulsar wind nebula (PWN), closely resembling the Crab, for which no thermal shell emission has been detected in X-rays. Recent Spitzer observations revealed an infrared (IR) shell containing a dozen point sources arranged in a ring-like structure, previously proposed to be young stellar objects. An extended knot of emission located in the NW part of the shell appears to be aligned with the pulsar's X-ray jet, suggesting a possible interaction with the shell material. Surprisingly, the IR spectrum of the knot resembles the spectrum of freshly formed dust in Cas A, and is dominated by an unidentified dust emission feature at 21 μm. The spectra of the shell also contain various emission lines and show that some are significantly broadened, suggesting that they originate in rapidly expanding supernova (SN) ejecta. We present the first evidence that the PWN is driving shocks into expanding SN ejecta and we propose an alternative explanation for the origin of the IR emission in which the shell is composed entirely of SN ejecta. In this scenario, the freshly formed SN dust is being heated by early-type stars belonging to a cluster in which the SN exploded. Simple dust models show that this interpretation can give rise to the observed shell emission and the IR point sources.

title: SIMULTANEOUS CHANDRA AND RXTE SPECTROSCOPY OF THE MICROQUASAR H 1743 − 22 : CLUES TO DISK WIND AND JET FORMATION FROM A VARIABLE IONIZED OUTFLOW
abstract: We observed the bright phase of the 2003 outburst of the Galac tic black hole candidate H 1743 − 22 in Xrays simultaneously withChandra andRXTE on four occasions. The Chandra/HETGS spectra reveal narrow, variable (He-like) Fe XXV and (H-like) Fe XXVI resonance abs orption lines. In the first observation, the Fe XXVI line has a FWHM of 1800± 400 km/s and a blue-shift of 700 ± 200 km/s, suggesting that the highly ionized medium is an outflow. Moreover, the Fe XXV line is obse rved to vary significantly on a timescale of a few hundred seconds in the first observation, which correspo nds to the Keplerian orbital period at approximately 104 rg (whererg = GM/c2). Our models for the absorption geometry suggest that a comb ination of geometric effects and changing ionizing flux are required to account fo r he large changes in line flux observed between observations, and that the absorption likely occurs at a rad ius less than 10 4 rg for a 10M⊙ black hole. Viable models for the absorption geometry include cyclic absorpti n due to an accretion disk structure, absorption in a clumpy outflowing disk wind, or possibly a combination of the se two. If the wind in H 1743 −322 has unity filling factor, the highest implied mass outflow rate is 20% of the Edd ington mass accretion rate. This wind may be a hot precursor to the Seyfert-like, outflowing “warm absorber” g eometries recently found in the Galactic black holes GX 339-4 and XTE J1650 −500. We discuss these findings in the context of ionized Fe abs orption lines found in the spectra of other Galactic sources, and connections to warm absorbers, winds, and jets in other accreting systems.

title: THE SOLAR WIND CHARGE-TRANSFER X-RAY EMISSION IN THE 1/4 keV ENERGY RANGE: INFERENCES ON LOCAL BUBBLE HOT GAS AT LOW Z
abstract: We present calculations of the heliospheric solar wind charge-exchange (SWCX) emission spectra and the resulting contributions of this diffuse background in the ROSAT 1/4 keV bands. We compare our results with the soft X-ray background (SXRB) emission detected in front of 378 identified shadowing regions during the ROSAT All-Sky Survey. This foreground component is principally attributed to the hot gas of the so-called Local Bubble (LB), an irregularly shaped cavity of ~50-150 pc around the Sun, which is supposed to contain ~106 K plasma. Our results suggest that the SWCX emission from the heliosphere is bright enough to account for most of the foreground emission toward the majority of low galactic latitude directions, where the LB is the least extended. On the other hand, in a large part of directions with galactic latitude above 30°, the heliospheric SWCX intensity is significantly smaller than the measured one. However, the SWCX R2/R1 band ratio differs slightly from the data in the galactic center direction, and more significantly in the galactic anticentre direction where the observed ratio is the smallest. Assuming that both SWCX and hot gas emission are present and their relative contributions vary with direction, we tested a series of thermal plasma spectra for temperatures ranging from 10 5 to 10 6.5 K and searched for a combination of SWCX spectra and thermal emission matching the observed intensities and band ratios, while simultaneously being compatible with O VI emission measurements. In the frame of collisional equilibrium models and for solar abundances, the range we derive for hot gas temperature and emission measure cannot reproduce the Wisconsin C/B band ratio. This implies that accounting for SWCX contamination does not remove these known disagreements between data and classical hot gas models. We emphasize the need for additional atomic data, describing consistently EUV and X-ray photon spectra of the charge-exchange emission of heavier solar wind ions.

title: Radiation effects in detector electronics
abstract: Radiation effects produced in electronics for detectors operated at intense high-energy particle accelerators are reviewed. Both displacement damage in semiconductor material and long-lived ionization effects produced by charge trapping in dielectrics near interfaces are potentially serious. Hardening and test methods must recognize the particular circuit's functional requirements. The dominant defects and appropriate hardening method depend on the important parameter (e.g., offset, leakage, noise) as well as the operating frequency.