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Three-Dimensional Magnetohydrodynamic Simulation of a Global Solar Corona Using a Temperature Distribution Map Obtained from SOHO EIT Measurements
Liu, Yang; Hayashi, Keiji; Hoeksema, Todd +2 more
The temperature at the base of the solar corona is one of the important factors in determining the solar coronal structure. In this Letter, we performed the time-dependent magnetohydrodynamic (MHD) simulation for the solar corona utilizing the temperature map derived from the multiwavelength observation by the EUV Imaging Telescope (EIT) on the So…
The Fundamental Plane in RX J0142.0+2131: A Galaxy Cluster Merger at z=0.28
Jørgensen, Inger; Chiboucas, Kristin; Barr, Jordi +2 more
We present the fundamental plane (FP) in the z=0.28 cluster of galaxies RX J0142.0+2131. There is no evidence for a difference in the slope of the FP when compared with the Coma Cluster, although the internal scatter is larger. On average, stellar populations in RX J0142.0+2131 have rest-frame V-band mass-to-light ratios (M/LV) 0.29+/-0…
Extended X-Ray Emission from QSOs
Fu, Hai; Stockton, Alan; Canalizo, Gabriela +1 more
We report Chandra ACIS observations of the fields of four QSOs showing strong extended optical emission-line regions. Two of these show no evidence for significant extended X-ray emission. The remaining two fields, those of 3C 249.1 and 4C 37.43, show discrete (but resolved) X-ray sources at distances ranging from ~10 to ~40 kpc from the nucleus. …
Silicate Emission Profiles from Low-Mass Protostellar Disks in the Orion Nebula: Evidence for Growth and Thermal Processing of Grains
Smith, Nathan; Bally, John; Kassis, Marc +2 more
We present 8-13 µm low-resolution spectra (R~100) of eight low-mass protostellar objects (``proplyds'') in the Orion Nebula using the Long Wavelength Spectrometer at the W. M. Keck Observatory. All but one of the sources in our sample show strong circumstellar silicate emission, with profiles that are qualitatively similar to those seen in s…
The Discovery of a P Cygni Analog in M31
Massey, Philip
We present spectroscopy and discuss the photometric history of a previously obscure star in M31. The spectrum of the star is an extremely close match to that of P Cygni, one of the archetypes of luminous blue variables (LBVs). The star has not shown much variability over the past 40 years (<0.2 mag), although small-scale (0.05 mag) variations o…
The Seismic Correlation Signature of Moderate-Scale Flow in the Sun
Woodard, M. F.
Flows in the solar convection zone introduce correlation between distinct horizontal-wavevector and frequency components of wave motion in the Sun. We derive expressions for the linear sensitivity of helioseismic correlation data to subphotospheric supergranular-scale flow, for use in helioseismic inversions. The sensitivity calculations are based…
High-Ionization Forbidden Lines in the UV Spectrum of AG Draconis
Young, P. R.; Dupree, A. K.; Espey, B. R. +1 more
High-ionization forbidden lines from Ca VII, Fe VII, Mg V, Mg VI, Mg VII, and Si VII are found in recent Hubble Space Telescope STIS ultraviolet spectra of the symbiotic star AG Draconis. These species have ionization potentials between 99 and 205 eV, which are unexpected due to the high density (~1010 cm-3) of the AG Dra neb…
Large Silicon Abundance in Photodissociation Regions
Nakagawa, Takao; Onaka, Takashi; Tomono, Daigo +3 more
We have made one-dimensional raster scan observations of the ρ Oph and σ Sco star-forming regions with two spectrometers (SWS and LWS) on board the ISO. In the ρ Oph region, [Si II] 35 µm, [O I] 63 µm, 146 µm, [C II] 158 µm, and the H2 pure rotational transition lines S(0) to S(3) are detected, and the photodisso…
Adaptive-Optics-Assisted Near-Infrared Spectroscopy of SVS 13 and Its Jet
Smith, M. D.; Ray, T. P.; Nisini, B. +5 more
We present long-slit H- and K-band spectroscopy of the low-mass outflow source SVS 13, obtained with the adaptive-optics-assisted imager-spectrometer NACO on the VLT. With a spatial resolution of <0.25" and a pixel scale of 0.027", we precisely establish the relative offsets of H2, [Fe II], CO, H I, and Na I components from the sourc…
Discovery of a 3.6 hr Eclipsing Luminous X-Ray Binary in the Galaxy NGC 4214
Tennant, Allyn F.; Swartz, Douglas A.; Ghosh, Kajal K. +3 more
We report the discovery of an eclipsing X-ray binary with a 3.62 hr period within 24" of the center of the dwarf starburst galaxy NGC 4214. The orbital period places interesting constraints on the nature of the binary and allows for a few very different interpretations. The most likely possibility is that the source lies within NGC 4214 and has an…