Search Publications
Oxygen Abundance and Energy Deposition in the Slow Coronal Wind
Abbo, L.; Antonucci, E.; Telloni, D.
Observations of the extended corona obtained with the Ultraviolet Coronagraph Spectrometer (UVCS) on board the Solar and Heliospheric Observatory (SOHO) during the solar minimum years 1996 and 1997 have been analyzed to derive the oxygen abundance in the outer corona. A comparison of the absolute coronal abundance, measured in the coronal regions …
X-Ray Observations of SN 1006 with INTEGRAL
Rho, J.; Lund, N.; Boggs, S. E. +4 more
The remnant of the supernova of 1006 AD, the remnant first showing evidence for the presence of X-ray synchrotron emission from shock-accelerated electrons, was observed for ~1000 ks with INTEGRAL in order to study electron acceleration to very high energies. The aim of the observation was to characterize the synchrotron emission and attempt to de…
Morphology and Evolution of Emission-Line Galaxies in the Hubble Ultra Deep Field
Panagia, N.; Ferguson, H. C.; Koekemoer, A. M. +8 more
We investigate the properties and evolution of a sample of galaxies selected to have prominent emission lines in low-resolution grism spectra of the Hubble Ultra Deep Field (HUDF). These objects, eGRAPES, are late-type blue galaxies characterized by small proper sizes (R50<=2 kpc) in the 4350 Å rest frame, low masses (5×109
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…