Search Publications
Missions
Journals
Publication Years
Waves as the Source of Apparent Twisting Motions in Sunspot Penumbrae
Solanki, S. K.; Bharti, L.; Hirzberger, J. +2 more
The motion of dark striations across bright filaments in a sunspot penumbra has become an important new diagnostic of convective gas flows in penumbral filaments. The nature of these striations has, however, remained unclear. Here, we present an analysis of small-scale motions in penumbral filaments in both simulations and observations. The simula…
The vertical distribution of the Venus NO nightglow: Limb profiles inversion and one-dimensional modeling
Bertaux, J. -L.; Gérard, J. -C.; Soret, L. +2 more
Ultraviolet (UV) spectra of the δ (190-240 nm) and γ (225-270 nm) bands of the nitric oxide (NO) molecule have been measured on the nightside of the atmosphere of Venus with the Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus (SPICAV) instrument on board Venus Express (VEX). Excited NO molecules on the nightside of the…
Hot gas in groups: NGC 5328 and the intriguing case of NGC 4756 with XMM-Newton
Wolter, A.; Marino, A.; Trinchieri, G. +2 more
Context. Environment appears to have a strong influence on the fundamental properties of galaxies, modifying both their morphologies and their star formation histories. Similarly, galaxies play a role in determining the properties of the hot intergalactic medium in groups, heating and enriching it through a variety of mechanisms. NGC 5238 and NGC …
Observations of Outflowing Ultraviolet Absorbers in NGC 4051 with the Cosmic Origins Spectrograph
Turner, T. J.; Kraemer, S. B.; Crenshaw, D. M. +6 more
We present new Hubble Space Telescope (HST)/Cosmic Origins Spectrograph (COS) observations of the narrow-line Seyfert 1 galaxy NGC 4051. These data were obtained as part of a coordinated observing program including X-ray observations with the Chandra/High Energy Transmission Grating (HETG) spectrometer and Suzaku. We detected nine kinematic compon…
Magnetic Topology of a Naked Sunspot: Is It Really Naked?
Sainz Dalda, A.; Tarbell, T. D.; Vargas Domínguez, S.
The high spatial, temporal, and spectral resolution achieved by Hinode instruments gives much better understanding of the behavior of some elusive solar features, such as pores and naked sunspots. Their fast evolution and, in some cases, their small sizes have made their study difficult. The moving magnetic features (MMFs) have been studied during…
The enigmatic black hole candidate and X-ray transient IGR J17091-3624 in its quiescent state as seen with XMM-Newton
Altamirano, D.; Wijnands, R.; Yang, Y. J.
We report on two short XMM-Newton observations performed in 2006 August and 2007 February during the quiescence state of the enigmatic black hole candidate system IGR J17091-3624. During both observations the source was clearly detected. Although the errors on the estimated fluxes are large, the source appears to be brighter by several tens of per…
O/O 2 emissions in the Venus nightglow
Chanover, Nancy J.; Bida, Thomas A.; Slanger, Tom G. +1 more
The oxygen green line is one of the most characteristic features in the terrestrial visible nightglow; it can be seen in the Venus nightglow, but with much greater intensity variation than in the terrestrial case. Here we synthesize our current understanding of the green line in the Venus nightglow and discuss what might be expected observationall…
A Multi-wavelength Study of the Jet, Lobes, and Core of the Quasar PKS 2101-490
Birkinshaw, M.; Worrall, D. M.; Schwartz, D. A. +9 more
We present a detailed study of the x-ray, optical, and radio emission from the jet, lobes, and core of the quasar PKS 2101-490 as revealed by new Chandra, Hubble Space Telescope (HST), and ATCA images. We extract the radio to x-ray spectral energy distributions from seven regions of the 13'' jet, and model the jet x-ray emission in terms of Dopple…
Measuring the orbital inclination of Z Andromedae from Rayleigh scattering
Skopal, A.; Shagatova, N.
Context. The orbital inclination of the symbiotic prototype Z And has not been established yet. At present, two very different values are considered, i ~ 44° and i ≳ 73°. The correct value of i is a key parameter in, for example, modeling the highly-collimated jets of Z And.
Aims: To measure the orbital inclination of Z And.
Methods: Fir…
A model for the vertical sound speed and absorption profiles in Titan's atmosphere based on Cassini-Huygens data
Petculescu, Andi; Achi, Peter
Measurements of thermodynamic quantities in Titan's atmosphere during the descent of Huygens in 2005 are used to predict the vertical profiles for the speed and intrinsic attenuation (or absorption) of sound. The calculations are done using one author's previous model modified to accommodate non-ideal equations of state. The vertical temperature p…