Search Publications
Test for Alfvén Wave Signatures in a Solar Coronal Hole
Moran, Thomas G.
Using spectral line observations to study minor ion motions in a solar coronal hole, a test was made for the presence of Alfvén waves. From this we conclude that the Alfvén wave flux into the upper portion of the hole is not significant. The SOHO/SUMER ultraviolet spectrograph was used to observe 22 coronal ions with masses ranging from 14mH<…
New Laboratory Spectra of Isolated β-SiC Nanoparticles: Comparison with Spectra Taken by the Infrared Space Observatory
Mutschke, H.; Henning, Th.; Klein, R. +1 more
We present new laboratory infrared spectra of matrix-isolated β-SiC nanoparticles, which perfectly match the band profile of the 11+ µm feature observed in carbon stars. The new laboratory spectra differ in the shape of the band profile from former measurements of SiC nanoparticles thanks to the matrix-isolation technique which allows to obt…
Diffuse X-Ray Emission from M101
Mukai, K.; Kuntz, K. D.; Snowden, S. L. +1 more
The total 0.45-1.0 keV luminosity of M101 is 3.2×1039 ergs s-1, of which 2.3×1039 ergs s-1 is due to diffuse emission. (Chandra observes only ~60% of the diffuse emission observed by ROSAT because of its superior point-source detection.) Of the diffuse emission seen by Chandra, no more than 6% can be due…
Elemental Abundances for the 1996 Streamer Belt
Wurz, P.; Raymond, J. C.; Uzzo, M. +2 more
The purpose of this paper is to explore the observed physical characteristics of the solar corona streamer belt from 1996 June 1 to August 5. The UV spectral data was collected by the Ultraviolet Coronagraph Spectrometer (UVCS) instrument on board the Solar and Heliospheric Observatory (SOHO) spacecraft. From this data the abundances of oxygen, si…
The Nuclear Spectral Energy Distribution of NGC 6251: A BL Lacertae Object in the Center of an FR I Radio Galaxy
Chiaberge, Marco; Capetti, Alessandro; Gilli, Roberto +1 more
We determine the nuclear spectral energy distribution (SED) from the radio to the gamma-ray band for the FR I radio galaxy NGC 6251, by using data from the literature and analyzing Hubble Space Telescope and X-ray archival data. In the logν-log(νFν) representation, the SED has two broad peaks, and it is remarkably similar to those of bl…
The X-Ray Binary GRS 1741.9-2853 in Outburst and Quiescence
Muno, M. P.; Baganoff, F. K.; Arabadjis, J. S.
We report Chandra and XMM-Newton observations of the transient neutron star low-mass X-ray binary GRS 1741.9-2853. Chandra detected the source in outburst on 2000 October 26 at an X-ray luminosity of ~1036 ergs s-1 (2-8 keV; 8 kpc), and in quiescence on 2001 July 18 at ~1032 ergs s-1. The latter observat…
The Multicolored Hot Interstellar Medium of ``the Antennae'' Galaxies (NGC 4038/4039)
Zezas, A.; Fabbiano, G.; Krauss, M. +2 more
We report the results of the analysis of the extended soft emission discovered in the Chandra ACIS pointing at the merging system NGC 4038/4039 (``the Antennae''). We present a multicolor X-ray image that suggests both extensive absorption by the dust in this system, peaking in the contact region, as well as variations in the temperature of differ…
Host Galaxies of Low-z Radio-loud Quasars: A Search of Hubble Space Telescope Archives
Treves, Aldo; Falomo, Renato; Pagani, Claudio
We searched the Hubble Space Telescope (HST) archives for unpublished Wide Field Planetary Camera 2 images of low-redshift (z<0.5) radio-loud quasars (RLQs). This led to the identification of 11 objects. Here we present the results of the analysis of these images from which we derive the properties of their host galaxies. All objects are clearl…
Hubble Space Telescope Imaging in the Chandra Deep Field-South. III. Quantitative Morphology of the 1 Million Second Chandra Counterparts and Comparison with the Field Population
Tozzi, P.; Hasinger, G.; Rosati, P. +8 more
We present quantitative morphological analyses of 37 Hubble Space Telescope (HST)/WFPC2 counterparts of X-ray sources in the 1 Ms Chandra Deep Field-South (CDFS). We investigate (1) one-dimensional surface brightness profiles via isophotal ellipse fitting; (2) two-dimensional, point-spread function-convolved, bulge+disk+nucleus profile fitting; (3…
A Hubble Space Telescope WFPC2 Snapshot Survey of 2MASS-selected Red QSOs
Hines, Dean C.; Armus, Lee; Schmidt, Gary D. +5 more
Using simple infrared color selection, the Two Micron All Sky Survey (2MASS) has found a large number of red, previously unidentified, radio-quiet quasi-stellar objects (QSOs). Although missed by UV/optical surveys, the 2MASS QSOs have Ks-band luminosities that are comparable to ``classical'' QSOs. This suggests the possible discovery o…