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The Cheshire Cat Gravitational Lens: The Formation of a Massive Fossil Group
White, Raymond E., III; Maksym, W. Peter; Dupke, Renato +3 more
The Cheshire Cat is a relatively poor group of galaxies dominated by two luminous elliptical galaxies surrounded by at least four arcs from gravitationally lensed background galaxies that give the system a humorous appearance. Our combined optical/X-ray study of this system reveals that it is experiencing a line of sight merger between two groups …
Evolution and Flare Activity of δ -Sunspots in Cycle 23
Takizawa, K.; Kitai, R.
The emergence and magnetic evolution of solar active regions (ARs) of β γ δ -type, which are known to be highly flare-productive, were studied with SOHO/MDI data in Cycle 23. We selected 31 ARs that can be observed from their birth phase as unbiased samples for our study. From the analysis of the magnetic topology (twist and writhe), we obtained t…
Far-infrared observations of an unbiased sample of gamma-ray burst host galaxies
Ivison, R. J.; Scott, D.; Fritz, J. +19 more
Gamma-ray bursts (GRBs) are the most energetic phenomena in the Universe; believed to result from the collapse and subsequent explosion of massive stars. Even though it has profound consequences for our understanding of their nature and selection biases, little is known about the dust properties of the galaxies hosting GRBs. We present analysis of…
IGR J14488-4008: an X-ray peculiar giant radio galaxy discovered by INTEGRAL
Venturi, T.; Dallacasa, D.; Bird, A. J. +5 more
In this paper, we report the discovery and detailed radio/X-ray analysis of a peculiar giant radio galaxy (GRG) detected by INTEGRAL, IGR J14488-4008. The source has been recently classified as a Seyfert 1.2 galaxy at redshift 0.123; the radio data denote the source to be a type II Fanaroff-Riley radio galaxy, with a linear projected size exceedin…
Mars as a comet: Solar wind interaction on a large scale
Holmstrom, Mats; Wang, Xiao-Dong
Looking at the Mars-solar wind interaction on a larger spatial scale than the near Mars region, the planet can be seen as an ion source interacting with the solar wind, in many ways like a comet, but with a smaller ion source region. Here we study the interaction between Mars and the solar wind using a hybrid model (particle ions and fluid electro…
3D magnetic field configuration of small-scale reconnection events in the solar plasma atmosphere
Shimizu, T.
The outer solar atmosphere, i.e., the corona and the chromosphere, is replete with small energy-release events, which are accompanied by transient brightening and jet-like ejections. These events are considered to be magnetic reconnection events in the solar plasma, and their dynamics have been studied using recent advanced observations from the H…
Morpho-kinematics of the planetary nebula NGC 3242: an analysis beyond its multiple-shell structure
Gómez-Muñoz, M. A.; Vázquez, R.; Ayala, S. +3 more
In this paper we present the results of optical high-resolution imaging and spectroscopy of the complex planetary nebula (PN) NGC 3242. Our study is based on the analysis of the narrow-band Hα λ6563, [O III] λ5007, [N II] λ6584, and [S II] λ6724 Å images, and high-resolution spectroscopy using spectral ranges centred on the Hα λ6564, [N II] λ6583,…
Time variations of narrow absorption lines in high resolution quasar spectra
York, D. G.; Péroux, C.; Bergeron, J. +2 more
Aims: We have searched for temporal variations of narrow absorption lines in high resolution quasar spectra. A sample of five distant sources were assembled, for which two spectra are available, either VLT/UVES or Keck/HIRES, which were taken several years apart.
Methods: We first investigate under which conditions variations in absorpti…
Ubiquitous time variability of integrated stellar populations
van Dokkum, Pieter G.; Choi, Jieun; Conroy, Charlie
Long-period variable stars arise in the final stages of the asymptotic giant branch phase of stellar evolution. They have periods of up to about 1,000 days and amplitudes that can exceed a factor of three in the I-band flux. These stars pulsate predominantly in their fundamental mode, which is a function of mass and radius, and so the pulsation pe…
Effects of Saturn's magnetospheric dynamics on Titan's ionosphere
Gurnett, D. A.; Jackman, C. M.; Kurth, W. S. +9 more
We use the Cassini Radio and Plasma Wave Science/Langmuir probe measurements of the electron density from the first 110 flybys of Titan to study how Saturn's magnetosphere influences Titan's ionosphere. The data is first corrected for biased sampling due to varying solar zenith angle and solar energy flux (solar cycle effects). We then present res…