Search Publications
The Uncertainty of Local Background Magnetic Field Orientation in Anisotropic Plasma Turbulence
Saur, J.; Gerick, F.; von Papen, M.
In order to resolve and characterize anisotropy in turbulent plasma flows, a proper estimation of the background magnetic field is crucially important. Various approaches to calculating the background magnetic field, ranging from local to globally averaged fields, are commonly used in the analysis of turbulent data. We investigate how the uncertai…
The Formation of IRIS Diagnostics. IX. The Formation of the C I 135.58 NM Line in the Solar Atmosphere
Carlsson, Mats; Leenaarts, Jorrit; Lin, Hsiao-Hsuan
The C I 135.58 nm line is located in the wavelength range of NASA’s Interface Region Imaging Spectrograph (IRIS) small explorer mission. We study the formation and diagnostic potential of this line by means of non local-thermodynamic-equilibrium modeling, employing both 1D and 3D radiation-magnetohydrodynamic models. The C I/C II ionization balanc…
Detection of Prominent Stellar Disks in the Progenitors of Present-day Massive Elliptical Galaxies
Ho, Luis C.; Mobasher, Bahram; Canalizo, Gabriela +1 more
Massive galaxies at high redshifts (z > 2) show different characteristics from their local counterparts: they are compact and most likely have a disk. In this study, we trace the evolution of local massive galaxies by performing a detailed morphological analysis, namely, fitting single Sérsic profiles and performing bulge+disk decompositions. W…
CTIO, ROSAT HRI, and Chandra ACIS Observations of the Archetypical Mixed-morphology Supernova Remnant W28 (G6.4-0.1)
Kargaltsev, Oleg; Rho, Jeonghee; Hare, Jeremy +6 more
We present a joint analysis of optical emission-line and X-ray observations of the archetypical Galactic mixed-morphology supernova remnant (MMSNR) W28 (G6.4-0.1). MMSNRs comprise a class of sources whose shell-like radio morphology contrasts with a filled center in X-rays; the origin of these contrasting morphologies remains uncertain. Our CTIO i…
Multi-spacecraft Observations of the Coronal and Interplanetary Evolution of a Solar Eruption Associated with Two Active Regions
Wang, Rui; Yang, Zhongwei; Liu, Ying D. +3 more
We investigate the coronal and interplanetary evolution of a coronal mass ejection (CME) launched on 2010 September 4 from a source region linking two active regions (ARs), 11101 and 11103, using extreme ultraviolet imaging, magnetogram, white-light, and in situ observations from SDO, STEREO, SOHO, VEX, and Wind. A potential-field source-surface m…
Physical Properties of the Very Young PN Hen3-1357 (Stingray Nebula) Based on Multiwavelength Observations
Hubrig, S.; Otsuka, Masaaki; Parthasarathy, M. +1 more
We carried out a detailed analysis of the interesting and important very young planetary nebula (PN) Hen3-1357 (Stingray Nebula) based on a unique data set of optical to far-IR spectra and photometric images. We calculated the abundances of nine elements using collisionally excited lines (CELs) and recombination lines (RLs). The RL C/O ratio indic…
X-Ray Studies of the Extended TeV Gamma-Ray Source VER J2019+368
Mizuno, T.; Takahashi, H.; Katsuta, J. +3 more
This article reports the results of X-ray studies of the extended TeV γ-ray source VER J2019+368. Suzaku observations conducted to examine properties of the X-ray pulsar wind nebula (PWN) around PSR J2021+3651 revealed that the western region of the X-ray PWN has a source extent of 15\prime × 10\prime with the major axis orie…
Variations between Dust and Gas in the Diffuse Interstellar Medium. II. Search for Cold Gas
Heiles, Carl; Reach, William T.; Bernard, Jean-Philippe
The content of interstellar clouds, in particular the inventory of diffuse molecular gas, remains uncertain. We identified a sample of isolated clouds, approximately 100 M⊙ in size, and used the dust content to estimate the total amount of gas. In Paper I, the total inferred gas content was found significantly larger than that seen in 2…
Toward Understanding The B[e] Phenomenon. VI. Nature and Spectral Variations of HD 85567.
Reichart, D. E.; Miroshnichenko, A. S.; Haislip, J. B. +7 more
We report the results of high-resolution (R ∼ 80,000) spectroscopic observations of the emission-line object HD 85567, which has been classified as an FS CMa type object or a pre-main-sequence star. The main goal is to put more constraints on the object’s fundamental parameters, as well as on its nature and evolutionary state. Absorption lines in …
A Closer Look at the Alpha Persei Coronal Conundrum
Ayres, Thomas R.
A ROSAT survey of the Alpha Per open cluster in 1993 detected its brightest star, the mid-F supergiant α Persei: the X-ray luminosity and spectral hardness were similar to coronally active late-type dwarf members. Later, in 2010, a Hubble Cosmic Origins Spectrograph SNAPshot of α Per found the far-ultraviolet (FUV) coronal-proxy Si IV unexpectedly…