Search Publications
The Saturnian satellite Rhea as seen by Cassini VIMS
Baines, Kevin H.; Buratti, Bonnie J.; Clark, Roger N. +16 more
Since the arrival of the Cassini spacecraft at Saturn in June 2004, the Visual and Infrared Mapping Spectrometer has obtained new spectral data of the icy satellites of Saturn in the spectral range from 0.35 to 5.2 µm. Numerous flybys were performed at Saturn’s second largest satellite Rhea, providing a nearly complete coverage with pixel-gr…
Magnetic Fields of an Active Region Filament from Full Stokes Analysis of Si I 1082.7 nm and He I 1083.0 nm
Liu, Y.; Lagg, A.; Solanki, S. +1 more
Vector magnetic fields of an active region filament in the photosphere and upper chromosphere are obtained from spectro-polarimetric observations recorded with the Tenerife Infrared Polarimeter (TIP II) at the German Vacuum Tower Telescope. We apply Milne-Eddington inversions on full Stokes vectors of the photospheric Si I 1082.7 nm and the upper …
The nature of the unresolved extragalactic cosmic soft X-ray background
Finoguenov, A.; Vignali, C.; Gilli, R. +12 more
In this paper we investigate the power spectrum of the unresolved 0.5-2 keV cosmic X-ray background (CXB) with deep Chandra 4-Msec (Ms) observations in the Chandra Deep Field South (CDFS). We measured a signal that, on scales >30 arcsec, is significantly higher than the shot noise and is increasing with angular scale. We interpreted this signal…
Charge-exchange X-ray emission of nearby star-forming galaxies
Wang, Q. Daniel; Liu, Jiren; Mao, Shude
Properties of hot gas outflows from galaxies are generally measured from associated X-ray line emission assuming that it represents atomic transitions in thermally excited hot gas. X-ray line emission, however, can also arise from the charge exchange between highly ionized ions and neutral species. The Kα triplet of He-like ions can be used as a p…
Measuring Microlensing Using Spectra of Multiply Lensed Quasars
Muñoz, J. A.; Mediavilla, E.; Motta, V. +1 more
We report on a program of spectroscopic observations of gravitationally lensed QSOs with multiple images. We seek to establish whether microlensing is occurring in each QSO image using only single-epoch observations. We calculate flux ratios for the cores of emission lines in image pairs to set a baseline for no microlensing. The offset of the con…
Electric field structure inside the secondary island in the reconnection diffusion region
Deng, X. H.; Huang, S. Y.; Zhou, M.
Secondary islands have recently been intensively studied because of their essential role in dissipating energy during reconnection. Secondary islands generally form by tearing instability in a stretched current sheet, with or without guide field. In this article, we study the electric field structure inside a secondary island in the diffusion regi…
Localized density enhancements in the magnetosheath: Three-dimensional morphology and possible importance for impulsive penetration
Nilsson, H.; Karlsson, T.; Trotignon, J. -G. +3 more
We use Cluster multipoint density measurements, using the spacecraft potential, to identify localized density enhancements (>50%) in the magnetosheath, and estimate their three-dimensional morphology and orientation. Typically one dimension of the density enhancements is shorter than others, is directed perpendicular to the background magnetic …
Transmission spectrum of Venus as a transiting exoplanet
Tanga, P.; Ehrenreich, D.; Vidal-Madjar, A. +6 more
On 5-6 June 2012, Venus will be transiting the Sun for the last time before 2117. This event is an unique opportunity to assess the feasibility of the atmospheric characterisation of Earth-size exoplanets near the habitable zone with the transmission spectroscopy technique and provide an invaluable proxy for the atmosphere of such a planet. In thi…
Strong outburst activity of the X-ray pulsar X Persei during 2001-2011
Tsygankov, S.; Lutovinov, A.; Chernyakova, M.
We present the results of a comprehensive analysis of the X-ray pulsar X Persei over the period 1996-2011, encompassing the quite low state and subsequent strong outburst activity. Using data from the Rossi X-ray Timing Explorer (RXTE) and Swift, we detected several consecutive outbursts, during which the source luminosity increased by a factor of…
Velocity and Magnetic Transients Driven by the X2.2 White-light Flare of 2011 February 15 in NOAA 11158
Maurya, R. A.; Ambastha, A.; Vemareddy, P.
The first X-class flare of the current solar cycle 24 occurred in Active Region NOAA 11158 during its central meridian passage on 2011 February 15. This two-ribbon white-light flare was observed by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory. During the peak phase of the flare, we detected magnetic and Dopple…