Search Publications
Searching for possible siblings of the sun from a common cluster based on stellar space velocities
Bobylev, V. V.; Bajkova, A. T.; Mylläri, A. +1 more
We propose a kinematic approach to searching for the stars that could be formed with the Sun in a common "parent" open cluster. The approach consists in preselecting suitable candidates by the closeness of their space velocities to the solar velocity and analyzing the parameters of their encounters with the solar orbit in the past in a time interv…
A High-metallicity, High-velocity Cloud Along the Mrk 421 Sight Line: A Tracer of Complex M?
Shull, J. Michael; Danforth, Charles W.; Yao, Yangsen
We present a new measurement, 0.85-3.5 Z sun, of the metallicity of high-velocity cloud (HVC) Complex M by analyzing ultraviolet spectroscopic observations of the blazar Mrk 421 taken with the Cosmic Origins Spectrograph on the Hubble Space Telescope and the Far-Ultraviolet Spectroscopic Explorer. Although an HVC at V LSR = -…
A multi-wavelength study of the unidentified TeV gamma-ray source HESS J1626-490
Rolland, L.; Rowell, G.; Stegmann, C. +3 more
Aims: To explore the nature of the unidentified very-high-energy (VHE, E>100 GeV) gamma-ray source HESS J1626-490, we investigated the region in X-ray, sub-millimeter, and infrared energy bands.
Methods: So far only detected with the HESS array of imaging atmospheric Cherenkov telescopes, HESS J1626-490 could not be unambiguously iden…
Polar cap ion beams during periods of northward IMF: Cluster statistical results
Dandouras, I.; de Keyser, J.; Maggiolo, R. +3 more
Above the polar caps and during prolonged periods of northward IMF, the Cluster satellites detect upward accelerated ion beams with energies up to a few keV. They are associated with converging electric field structures indicating that the acceleration is caused by a quasi-static field-aligned electric field that can extend to altitudes higher tha…
On the driver of relativistic effect strength in Seyfert galaxies
Bianchi, S.; Guainazzi, M.; Longinotti, A. L. +2 more
Context. Spectroscopy of X-ray emission lines emitted from accretion discs around supermassive black holes is one of the most powerful probes of the accretion flow physics and geometry, while also providing in principle observational constraints on the black hole spin. Previous studies have suggested that relativistically broadened line profiles a…
Intracluster Medium of the Merging Cluster A3395
Singh, K. P.; Saikia, D. J.; Hunstead, R. W. +1 more
We present a detailed imaging and spectral analysis of the merging environment of the bimodal cluster A3395 using X-ray and radio observations. X-ray images of the cluster show five main constituents of diffuse emission: A3395 NE, A3395 SW, A3395 NW, A3395 W, and a filament connecting NE to W. X-ray surface brightness profiles of the cluster did n…
An X-ray underluminous cluster of galaxies in the 4Ms CDFS observations
Fiore, F.; Castellano, M.; Pentericci, L. +8 more
Aims: We investigate the properties of cluster ClG 0332-2747 at z = 0.734 in the GOODS-South field, which was undetected in the Chandra 2Ms observations. We explore possible scenarios to explain the discrepancy between its low X-ray emission and that expected from the M - LX relation.
Methods: We use the large public spectrosc…
Simulating the time-dependent response of Titan's upper atmosphere to periods of magnetospheric forcing
Westlake, Joseph; Waite, J. Hunter, Jr.; Bell, Jared M.
We demonstrate that a simulation of Titan's upper atmosphere can exhibit significant short-term temperature variations when exposed to globally averaged plasma heating rates over periods of 8 Earth days (0.5 Titan days). Temperature enhancements can range from 16 K when exposed to column-integrated, orbit-averaged heating rates of 2.5 × 108
History of plains resurfacing in the Scandia region of Mars
Tanaka, Kenneth L.; Skinner, James A.; Fortezzo, Corey M. +2 more
We present a preliminary photogeologic map of the Scandia region of Mars with the objective of reconstructing its resurfacing history. The Scandia region includes the lower section of the regional lowland slope of Vastitas Borealis extending about 500-1800 km away from Alba Mons into the Scandia sub-basin below -4800 m elevation. Twenty mapped geo…
Optical spectral classification of southern ultraluminous infrared galaxies
Lee, Myung Gyoon; Lee, Jong Chul; Hwang, Ho Seong +2 more
We present a study of the optical spectral properties of 115 ultraluminous infrared galaxies (ULIRGs) in the southern sky. Using the optical spectra obtained at the Cerro Tololo Inter-American Observatory (CTIO) 4 -m telescope and provided by the Two-degree Field (2dF) Galaxy Redshift Survey and the Six-degree Field (6dF) Galaxy Survey, we measure…