Search Publications
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…
GCM simulation of balloon trajectories on Titan
Lorenz, Ralph D.; Tokano, Tetsuya
Possible trajectories of passive balloons in Titan's troposphere are simulated with the instantaneous wind field predicted by a GCM (general circulation model). In most areas the basic motion of a balloon is a predominantly eastward or westward drift, depending on altitude, latitude and season of the balloon release point. Some meridional oscillat…
The Deepest Supernova Search is Realized in the Hubble Ultra Deep Field Survey
Riess, Adam G.; Strolger, Louis-Gregory
The Hubble Ultra Deep Field Survey has provided the deepest optical and near-infrared views of the universe yet, and has enabled a search for the most distant supernovae, to z~2.2. We have found four supernovae by searching spans of integrations of the Ultra Deep Field and the Ultra Deep Field Parallels taken with the Hubble Space Telescope paired…
Observations of the coronal dynamics associated with solar radio spike burst emission
Aurass, H.; Khan, J. I.
We present the results of an analysis of multi-wavelength data for a solar radio spike burst event which was observed on 1997 November 14 by the Solar Radio Spectrometers of the Astrophysikalisches Institut Potsdam (AIP). Using radio imaging data from the Nançay Radioheliograph we are able to determine the location of the spike burst emission site…
From the Sun to the Earth: impact of the 27-28 May 2003 solar events on the magnetosphere, ionosphere and thermosphere
Auchère, F.; Bocchialini, K.; Cornilleau-Wehrlin, N. +10 more
During the last week of May 2003, the solar active region AR 10365 produced a large number of flares, several of which were accompanied by Coronal Mass Ejections (CME). Specifically on 27 and 28 May three halo CMEs were observed which had a significant impact on geospace. On 29 May, upon their arrival at the L1 point, in front of the Earth's magne…
uvby - β Photoelectric Photometry of the Open Cluster α Per
Sareyan, J. -P.; Peña, J. H.
Absolute photoelectric photometry of stars in the direction of the Open Cluster α Per has been secured and is presented along with an analysis reinforced with all the available data in Strömgren uvby-β photometry compiled from the literature. Cluster membership is analyzed and the physical characteristics of the stars have been deduced. The member…
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…
Alfvén waves in the near-PSBL lobe: Cluster observations
Balogh, A.; Zhang, T. L.; Klecker, B. +14 more
Electromagnetic low-frequency waves in the magnetotail lobe close to the PSBL (Plasma Sheet Boundary Layer) are studied using the Cluster spacecraft. The lobe waves show Alfvénic properties and transport their wave energy (Poynting flux) on average toward the Earth along magnetic field lines. Most of the wave events are rich with oxygen (O+