Search Publications
Time Dependence in Relativistic Collisionless Shocks: Theory of the Variable ``Wisps'' in the Crab Nebula
Spitkovsky, Anatoly; Arons, Jonathan
We describe results from time-dependent numerical modeling of the collisionless reverse shock terminating the pulsar wind in the Crab Nebula. We treat the upstream relativistic wind as composed of ions and electron-positron plasma embedded in a toroidal magnetic field, flowing radially outward from the pulsar in a sector around the rotational equa…
The Ultraviolet Extinction Curve of Intraclump Dust in Taurus (TMC-1): Constraints on the 2175 Å Bump Absorber
Gordon, Karl D.; Whittet, D. C. B.; Clayton, Geoffrey C. +1 more
Ultraviolet extinction curves for three early-type stars that sample dust in the Taurus dark cloud in the vicinity of TMC-1 are analyzed to examine the contribution of internal (intraclump) dust to the total line-of-sight extinction. One of our selected targets samples only dust in the ``diffuse-screen'' component of the cloud, where the dust grai…
An Optical Survey of Supernova Remnants in M83
Blair, William P.; Long, Knox S.
Observations of the face-on spiral galaxy M83 (NGC 5236) performed at the Cerro Tololo Inter-American Observatory in Chile have yielded a catalog of optical supernova remnant (SNR) candidates. These observations were performed with the 4 m Blanco telescope and a prime focus CCD imaging system using narrowband interference filters centered on the l…
Extragalactic Source Counts at 24 Microns in the Spitzer First Look Survey
Im, M.; Frayer, D. T.; Helou, G. +18 more
We present the Spitzer Multiband Imaging Photometer 24 µm source counts in the Extragalactic First Look Survey (FLS) main, verification, and European Large Area ISO Survey N1 fields. Spitzer's increased sensitivity and efficiency in large areal coverage over previous infrared telescopes, coupled with the enhanced sensitivity of the 24 µ…
Helioseismic Mapping of the Magnetic Canopy in the Solar Chromosphere
Finsterle, W.; McIntosh, S. W.; Jefferies, S. M. +2 more
We determine the three-dimensional topography of the magnetic canopy in and around active regions by mapping the propagation behavior of high-frequency acoustic waves in the solar chromosphere.
Eros and Faint Red Galaxies
McCarthy, Patrick J.
This chapter reviews the properties of faint IR-selected field galaxies and the extremely red color-selected populations in particular. These populations are a mix of passively evolving stellar systems and heavily obscured star-forming galaxies. The star-forming component appears to constitute 20 50% of the population depending on the magnitude an…
Spatially and spectrally resolved 10 µm emission in Herbig Ae/Be stars
Waters, L. B. F. M.; Dominik, C.; van Boekel, R. +3 more
We present new mid-infrared spectroscopy of the emission from warm circumstellar dust grains in the Herbig Ae stars HD 100546, HD 97048 and HD 104237, with a spatial resolution of ≈0.9 arcsec. We find that the emission in the UIR bands at 8.6, 11.3 and (HD 97048 only) 12.7 µm is extended in the first two sources. The continuum emission is re…
Unveiling the nature of three INTEGRAL sources through optical spectroscopy
Palazzi, E.; Masetti, N.; Malizia, A. +2 more
The results of an optical spectroscopy campaign performed at the Astronomical Observatory of Bologna in Loiano (Italy) on three hard X-ray sources detected by INTEGRAL (IGR J17303-0601, IGR J18027-1455 and IGR J21247+5058) are presented. These data have allowed a determination of the nature for two of them, with IGR J17303-0601 being a low mass X-…
Magnetic turbulent spectra in the magnetosheath: new insights
Balogh, A.; Belmont, G.; Sahraoui, F. +4 more
Available from http://www.copernicus.org/site/EGU/annales/22/6/2283.htm?FrameEngine=false;
Revealing the X-Ray Emission Processes of Old Rotation-powered Pulsars: XMM-Newton Observations of PSR B0950+08, PSR B0823+26, and PSR J2043+2740
Weisskopf, Martin C.; Tennant, Allyn F.; Becker, Werner +4 more
We have completed part of a program to study the X-ray emission properties of old rotation-powered pulsars with XMM-Newton in order to probe and identify the origin of their X-radiation. The X-ray emission from these old pulsars is largely dominated by nonthermal processes. None of the observed spectra required adding a thermal component consistin…