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Hubble Space Telescope Imaging of HD 44179, The Red Rectangle
Gull, T. R.; Bond, Howard E.; Van Winckel, Hans +1 more
We present Hubble Space Telescope (HST) Wide Field Planetary Camera 2 and deep ground-based images of the Red Rectangle (RR), a bipolar proto-planetary nebula associated with the post-AGB binary system HD 44179. The high-resolution HST images reveal complex new structures, many of them unique to this object. The RR nebula is dominated by a discont…
Spaceship Earth Observations of the Easter 2001 Solar Particle Event
Dröge, Wolfgang; Evenson, Paul; Ruffolo, David +5 more
The largest relativistic (~1 GeV) solar proton event of the current solar activity cycle occurred on Easter 2001 (April 15). This was the first such event to be observed by Spaceship Earth, an 11-station network of neutron monitors optimized for measuring the angular distribution of solar cosmic rays. We derive the particle density and anisotropy …
Evidence for Gradual External Reconnection before Explosive Eruption of a Solar Filament
Moore, Ronald L.; Sterling, Alphonse C.
We observe a slowly evolving quiet-region solar eruption of 1999 April 18, using extreme-ultraviolet (EUV) images from the EUV Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO) and soft X-ray images from the Soft X-ray Telescope (SXT) on Yohkoh. Using difference images, in which an early image is subtracted from later images…
Astrophysical supplements to the ASCC-2.5. II. Membership probabilities in 520 Galactic open cluster sky areas
Scholz, R. -D.; Piskunov, A. E.; Kharchenko, N. V. +2 more
We present a catalogue (CSOCA ) of stars residing in 520 Galactic open cluster sky areas which is the result of the kinematic (proper motion) and photometric member selection of stars listed in the homogeneous All-sky Compiled Catalogue of 2.5 Million Stars (ASCC-2.5). We describe the structure and contents of the catalogue, the selection procedur…
Reconstructing galaxy histories from globular clusters
Jordán, Andrés; Marzke, Ronald O.; Côté, Patrick +1 more
Nearly a century after the true nature of galaxies as distant `island universes' was established, their origin and evolution remain great unsolved problems of modern astrophysics. One of the most promising ways to investigate galaxy formation is to study the ubiquitous globular star clusters that surround most galaxies. Globular clusters are compa…
Bright Points in the Internetwork Quiet Sun
Muller, R.; Márquez, I.; Sánchez Almeida, J. +2 more
High-resolution G-band images of the interior of a supergranulation cell show ubiquitous bright points (BPs; some 0.3 BPs per Mm2). They are located in intergranular lanes and often form chains of elongated blobs whose smallest dimension is at the resolution limit (135 km on the Sun). Most of them live for a few minutes, having peak int…
The SUMER spectral atlas of solar coronal features
Curdt, W.; Landi, E.; Feldman, U.
We present a spectral atlas of the solar corona in the far-ultraviolet (FUV) and extreme ultraviolet (EUV) wavelength range. The atlas is based on observations obtained between 670 Å and 1609 Å in first order of diffraction and between 465 and 670 Å in second order with the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) spectrograph o…
The HELLAS2XMM survey. VI. X-ray absorption in the 1df AGN sample through a spectral analysis
Maiolino, R.; Perola, G. C.; Fiore, F. +13 more
The spectroscopic analysis of 117 serendipitous sources in the HELLAS2XMM 1df (1 degree field) survey is described. Of these, 106 sources, of which 86% have a spectroscopic redshift, are used to evaluate the fraction of X-ray absorbed (log NH>22) Active Galactic Nuclei (AGN) in the 2-10 keV flux range 0.8-20×10-14 erg cm
Extreme-Ultraviolet and X-Ray Spectroscopy of a Solar Flare Loop Observed at High Time Resolution: A Case Study in Chromospheric Evaporation
Phillips, Kenneth J. H.; Brosius, Jeffrey W.
We present extreme-ultraviolet (EUV) and X-ray light curves and Doppler velocity measurements for a GOES class M2 solar flare observed in NOAA Active Region 9433 on 2001 April 24 at high time resolution with the Coronal Diagnostic Spectrometer (CDS) on board the Solar and Heliospheric Observatory (SOHO) satellite (9.83 s) and the Bragg Crystal Spe…
Jupiter's low-frequency radio spectrum from Cassini/Radio and Plasma Wave Science (RPWS) absolute flux density measurements
Kurth, W. S.; Cecconi, B.; Zarka, P.
We apply the calibration method developed by [2001] to the data from the Cassini/Radio and Plasma Wave Science (RPWS) High-Frequency Receiver in order to derive flux density measurements of six components of the Jovian low-frequency radio spectrum over the full frequency range of the instrument (3.5 kHz to 16.1 MHz). The estimated accuracy is bett…