Search Publications
Chandra Evidence for Extended X-Ray Structure in RY Tau
Skinner, Stephen L.; Güdel, Manuel; Audard, Marc
We report results of a sensitive Chandra ACIS-S observation of the classical T Tauri star RY Tau. Previous studies have shown that it drives a spectacular bipolar jet whose blueshifted component is traced optically along P.A. ≈ 295° at separations of 1farcs5-31'' from the star. Complex X-ray emission is revealed, including a very soft non-variable…
Underflight Calibration of SOHO/CDS and Hinode/EIS with EUNIS-07
Del Zanna, Giulio; Young, Peter R.; Brosius, Jeffrey W. +4 more
Flights of Goddard Space Flight Center's Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS) sounding rocket in 2006 and 2007 provided updated radiometric calibrations for Solar and Heliospheric Observatory/Coronal Diagnostic Spectrometer (SOHO/CDS) and Hinode/Extreme Ultraviolet Imaging Spectrometer (Hinode/EIS). EUNIS carried two independe…
Temperature Equilibration Behind the Shock Front: An Optical and X-Ray Study Of RCW 86
Vink, J.; Bassa, C. G.; Helder, E. A.
We study the electron-proton temperature equilibration behind several shocks of the RCW 86 supernova remnant. To measure the proton temperature, we use published and new optical spectra, all from different locations on the remnant. For each location, we determine the electron temperature from X-ray spectra, and correct for temperature equilibratio…
High-resolution Satellite Imaging of the 2004 Transit of Venus and Asymmetries in the Cytherean Atmosphere
Schneider, Glenn; Pasachoff, Jay M.; Widemann, Thomas
This paper presents the only space-borne optical-imaging observations of the 2004 June 8 transit of Venus, the first such transit visible from Earth since AD 1882. The high-resolution, high-cadence satellite images we arranged from NASA's Transition Region and Coronal Explorer (TRACE) reveal the onset of visibility of Venus's atmosphere and give f…
Model calculation of N2 Vegard-Kaplan band emissions in Martian dayglow
Bhardwaj, Anil; Jain, Sonal Kumar
A model for N2 Vegard-Kaplan (VK) band (A3Σu+ - X1Σg+) emissions in Martian dayglow has been developed to explain the recent observations made by the Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars (SPICAM) ultraviolet spectrograph aboard Mars …
Discovery of gamma- and X-ray pulsations from the young and energetic PSR J1357-6429 with Fermi and XMM-Newton
Camilo, F.; Cohen-Tanugi, J.; Grondin, M. -H. +20 more
Context. Since the launch of the Fermi satellite, the number of known gamma-ray pulsars has increased tenfold. Most gamma-ray detected pulsars are young and energetic, and many are associated with TeV sources. PSR J1357-6429 is a high spin-down power pulsar (Ė = 3.1 × 1036 erg s-1), discovered during the Parkes multibeam surv…
The Rotation of the White Light Solar Corona at Height 4 R sun from 1996 to 2010: A Tomographical Study of Large Angle and Spectrometric Coronagraph C2 Observations
Morgan, Huw
Solar rotational tomography is applied to Large Angle and Spectrometric Coronagraph (LASCO) C2/Solar and Heliospheric Observatory (SOHO) observations covering the period 1996-2010, resulting in a set of electron density maps at a height of 4 R sun from which rotation rates can be calculated. Large variation of rotation rates is measured…
Constructing a Galactic coordinate system based on near-infrared and radio catalogs
Zhu, Z.; Liu, J. -C.; Hu, B.
Context. The definition of the Galactic coordinate system was announced by the IAU Sub-Commission 33b on behalf of the IAU in 1958. An unrigorous transformation was adopted by the Hipparcos group to transform the Galactic coordinate system from the FK4-based B1950.0 system to the FK5-based J2000.0 system or to the International Celestial Reference…
Suzaku Discovery of a Hard Component Varying Independently of the Power-Law Emission in MCG -6-30-15
Makishima, Kazuo; Nakazawa, Kazuhiro; Yamada, Shin'ya +2 more
Focusing on hard X-ray variability, we reanalyzed Suzaku data of the Type I Seyfert galaxy MCG -6-30-15 obtained in 2006. Intensity-sorted spectroscopy and a principal-component analysis consistently revealed a very hard component that varies independently of the dominant power-law emission. Although the exact nature of this hard component has not…
Revisiting the Solar Tachocline: Average Properties and Temporal Variations
Basu, Sarbani; Antia, H. M.
The tachocline is believed to be the region where the solar dynamo operates. With over a solar cycle's worth of data available from the Michelson Doppler Imager and Global Oscillation Network Group instruments, we are in a position to investigate not merely the average structure of the solar tachocline, but also its time variations. We determine t…