Search Publications
Traveling solar-wind bulk-velocity fluctuations and their effects on electron heating in the heliosphere
Verscharen, Daniel; Fahr, Hans J.; Chashei, Igor V.
Ambient plasma electrons undergo strong heating in regions associated with compressive bulk-velocity jumps ΔU that travel through the interplanetary solar wind. The heating is generated by their specific interactions with the jump-inherent electric fields. After this energy gain is thermalized by the shock passage through the operation of the Bune…
Four-dimensional energy spectrum for space-time structure of plasma turbulence
Narita, Y.
A parametric model of the inertial-range energy spectrum is constructed for plasma turbulence in the four-dimensional wave vector and frequency domain. The model is based on that of the Eulerian wavenumber-frequency spectrum developed for describing fluid turbulence, and includes wave vector anisotropies in the three-dimensional wave vector domain…
Bulgeless Galaxies at Intermediate Redshift: Sample Selection, Color Properties, and the Existence of Powerful Active Galactic Nuclei
Bell, Eric F.; Brinchmann, Jarle; Bizzocchi, Luca +11 more
We present a catalog of bulgeless galaxies, which includes 19,225 objects selected in four of the deepest, largest multi-wavelength data sets available—COSMOS, AEGIS, GEMS, and GOODS—at intermediate redshift (0.4 <= z <= 1.0). The morphological classification was provided by the Advanced Camera for Surveys General Catalog (ACS-GC), which use…
First far-ultraviolet disk-integrated phase curve analysis of Mimas, Tethys and Dione from the Cassini-UVIS data sets
Hendrix, Amanda R.; Royer, Emilie M.
We perform an analysis of the photometric properties of the icy saturnian satellites at 180 nm, based on the first far-UV disk-integrated phase curves of Mimas, Tethys and Dione. Their interactions with the environment (the E-ring and the magnetosphere) are investigated, leading to a better understanding of the effects of exogenic processes on the…
The XMM-Newton view of the radio-loud narrow-line Seyfert 1 galaxy PMN J0948+0022
Bhatt, Himali; Bhattacharyya, Subir; Bhatt, Nilay +1 more
We analysed the archival XMM-Newton data of the radio-loud narrow-line Seyfert 1 galaxy PMN J0948+0022 in the energy range 0.3-10.0 keV. The X-ray data reveal that the spectrum in the 0.3-10.0 keV energy band is not a simple power law as previously described in the literature. Instead it consists of a power law with soft excess below 2.5 keV. The …
On the Dust Environment of Comet C/2012 S1 (ISON) from 12 AU Pre-perihelion to the End of its Activity around Perihelion
López-Moreno, J. J.; Moreno, F.; García, F. +48 more
A Monte Carlo dust tail model has been applied to extract the dust environment parameters of the comet C/2012 S1 (ISON) from both Earth-based and SOHO LASCO C3 observations, performed from about six astronomical units (AU) inbound, to just after perihelion passage, when only a small portion of the original comet nucleus has survived in the form of…
UV surface brightness of galaxies from the local universe to z ~ 5
Scarpa, Riccardo; Falomo, Renato; Lerner, Eric J.
The Tolman test for surface brightness (SB) dimming was originally proposed as a test for the expansion of the universe. The test, which is independent of the details of the assumed cosmology, is based on comparisons of the SB of identical objects at different cosmological distances. Claims have been made that the Tolman test provides compelling e…
Pre-perihelion activity of comet 67P/Churyumov-Gerasimenko
Schulz, R.; Tozzi, G. P.; Rożek, A. +3 more
Context. Comets are believed to hold a relatively pristine record of the physical and chemical processes that occurred during the formation and evolution of the solar system. Thorough investigations of these small bodies, such as the one that will be performed by the ESA/Rosetta cornerstone mission, are thus supposed to bring strong and unique con…
Fluctuation Spectroscopy: A New Probe of Old Stellar Populations
van Dokkum, Pieter G.; Conroy, Charlie
We introduce a new method to determine the relative contributions of different types of stars to the integrated light of nearby early-type galaxies. As is well known, the surface brightness of these galaxies shows pixel-to-pixel fluctuations due to Poisson variations in the number of giant stars. Differential spectroscopy of pixels as a function o…
Nighttime sensitivity of ionospheric VLF measurements to X-ray bursts from a remote cosmic source
Giménez de Castro, C. Guillermo; Raulin, Jean-Pierre; Correia, Emilia +2 more
On 22 January 2009, a series of X-ray bursts were emitted by the soft gamma ray repeater SGR J1550-5418. Some of these bursts produced enhanced ionization in the nighttime lower ionosphere. These ionospheric disturbances were studied using X-ray measurements from the Anti-Coincidence Shield of the Spectrometer for Integral onboard the Internationa…