Search Publications
Bright Strongly Lensed Galaxies at Redshift z ~ 6-7 behind the Clusters Abell 1703 and CL0024+16
Ford, H. C.; Infante, L.; Zheng, W. +10 more
We report on the discovery of three bright, strongly lensed objects behind Abell 1703 and CL0024+16 from a dropout search over 25 arcmin2 of deep NICMOS data, with deep ACS optical coverage. They are undetected in the deep ACS images below 8500 Å and have clear detections in the J and H bands. Fits to the ACS, NICMOS, and IRAC data yiel…
Low frequency eigenmodes of thin anisotropic current sheets and Cluster observations
Malova, H. V.; Petrukovich, A. A.; Zelenyi, L. M. +3 more
The eigenmodes of low frequency perturbations of thin anisotropic current sheets with a finite value of the normal magnetic field, are investigated in this paper. It is shown that two possible polarizations of symmetric and asymmetric modes (sausage and kink) exist where the growth rate of instabilities is positive. In addition, we demonstrate tha…
X-ray Insights into the Physics of Mini-BAL Quasar Outflows
Brandt, W. N.; Schneider, Donald P.; Gallagher, S. C. +1 more
We examine the ultraviolet and X-ray properties of 256 radio-quiet Sloan Digital Sky Survey quasars (QSOs) observed in X-rays with Chandra and/or XMM-Newton in order to study the relationship between QSOs with broad C IV absorption lines (BALs; width >2000 km s-1) and those with C IV mini-BALs (here defined to have widths of 1000-200…
Noise properties of the CoRoT data. A planet-finding perspective
Mazeh, T.; Guterman, P.; Aigrain, S. +30 more
In this short paper, we study the photometric precision of stellar light curves obtained by the CoRoT satellite in its planet-finding channel, with a particular emphasis on the time scales characteristic of planetary transits. Together with other articles in the same issue of this journal, it forms an attempt to provide the building blocks for a s…
The Nature of Optically Dull Active Galactic Nuclei in COSMOS
Kartaltepe, Jeyhan S.; Koekemoer, Anton M.; Trump, Jonathan R. +17 more
We present infrared, optical, and X-ray data of 48 X-ray bright, optically dull active galactic nuclei (AGNs) in the COSMOS field. These objects exhibit the X-ray luminosity of an AGN but lack broad and narrow emission lines in their optical spectrum. We show that despite the lack of optical emission lines, most of these optically dull AGNs are no…
The 5.25 and 5.7 µm Astronomical Polycyclic Aromatic Hydrocarbon Emission Features
Tielens, A. G. G. M.; Boersma, C.; Allamandola, L. J. +3 more
Astronomical mid-IR spectra show two minor polycyclic aromatic hydrocarbon (PAH) features at 5.25 and 5.7 µm (1905 and 1754 cm-1) that hitherto have been little studied, but contain information about the astronomical PAH population that complements that of the major emission bands. Here, we report a study involving both laboratory…
ACRIM-gap and TSI trend issue resolved using a surface magnetic flux TSI proxy model
Scafetta, Nicola; Willson, Richard C.
The ACRIM-gap (1989.5-1991.75) continuity dilemma for satellite TSI observations is resolved by bridging the satellite TSI monitoring gap between ACRIM1 and ACRIM2 results with TSI derived from Krivova et al.'s (2007) proxy model based on variations of the surface distribution of solar magnetic flux. `Mixed' versions of ACRIM and PMOD TSI composit…
Implosion in a Coronal Eruption
Wang, Haimin; Liu, Rui; Alexander, David
We present the observations of the contraction of the extreme-ultraviolet coronal loops overlying the flaring region during the preheating as well as the early impulsive phase of a GOES class C8.9 flare. During the relatively long, 6 minutes, preheating phase, hard X-ray (HXR) count rates at lower energies (below 25 keV) as well as soft X-ray flux…
Asymmetric Eruptive Filaments
Liu, Rui; Alexander, David; Gilbert, Holly R.
Filaments are often observed to erupt asymmetrically, during which one leg is fixed to the photosphere (referred to as the anchored leg) while the other undertakes most of the dynamic motions (referred to as the active leg) during the eruptive process. In this paper, we present observations of a group of asymmetric eruptive filaments, in which two…
Transit mapping of a starspot on CoRoT-2. Probing a stellar surface with planetary transits
Schmitt, J. H. M. M.; Czesla, S.; Guenther, E. W. +4 more
We analyze variations in the transit lightcurves of CoRoT-2b, a massive hot Jupiter orbiting a highly active G star. We use one transit lightcurve to eclipse-map a photospheric spot occulted by the planet. In this case study we determine the size and longitude of the eclipsed portion of the starspot and systematically study the corresponding uncer…