Search Publications
Missions
Journals
Publication Years
Cassini CAPS-ELS observations of negative ions in Titan's ionosphere: Trends of density with altitude
Lewis, G. R.; Coates, A. J.; Jones, G. H. +2 more
Observations with the Electron Spectrometer sensor of the Cassini Plasma Spectrometer (CAPS-ELS) have revealed the existence of negative ions in Titan's ionosphere. Negative ions are observed during encounters whenever the instrument points in the ram direction at altitudes 950-1400 km. Complex hydrocarbon and nitrile chemical processes are believ…
Deep observations of O2 toward a low-mass protostar with Herschel-HIFI
Caselli, Paola; van Dishoeck, Ewine F.; Visser, Ruud +13 more
Context. According to traditional gas-phase chemical models, O2 should be abundant in molecular clouds, but until recently, attempts to detect interstellar O2 line emission with ground- and space-based observatories have failed.
Aims: Following the multi-line detections of O2 with low abundances in the Orion a…
The Smooth Cyclotron Line in Her X-1 as Seen with Nuclear Spectroscopic Telescope Array
Hailey, Charles J.; Fürst, Felix; Klochkov, Dmitry +17 more
Her X-1, one of the brightest and best studied X-ray binaries, shows a cyclotron resonant scattering feature (CRSF) near 37 keV. This makes it an ideal target for a detailed study with the Nuclear Spectroscopic Telescope Array (NuSTAR), taking advantage of its excellent hard X-ray spectral resolution. We observed Her X-1 three times, coordinated w…
A Detailed X-Ray Investigation of ζ Puppis. II. The Variability on Short and Long Timescales
Nazé, Yaël; Gosset, Eric; Oskinova, Lidia M.
Stellar winds are a crucial component of massive stars, but their exact properties still remain uncertain. To shed some light on this subject, we have analyzed an exceptional set of X-ray observations of ζ Puppis, one of the closest and brightest massive stars. The sensitive light curves that were derived reveal two major results. On the one hand,…
Solar Magnetic Activity Cycles, Coronal Potential Field Models and Eruption Rates
Petrie, G. J. D.
We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated potential-field models based on longitudinal full-disk photospheric magnetograms from the National Solar Observatory…
Mineralogy and morphology of geologic units at Libya Montes, Mars: Ancient aqueously derived outcrops, mafic flows, fluvial features, and impacts
Seelos, Frank P.; Murchie, Scott L.; Mustard, John F. +19 more
There is ample evidence of both ancient and long-lasting fluvial activity and chemical alteration in the Libya Montes region south of Isidis Basin. The region hosts Noachian to Amazonian aged surface rocks with extensive outcrops of olivine- and pyroxene-bearing material. Libya Montes also features surface outcrops and/or deposits hosting Fe/Mg-sm…
Analysis of far-UV data of central stars of planetary nebulae: Occurrence and variability of stellar winds
Guerrero, M. A.; De Marco, O.
The occurrence of stellar wind in the central star of a planetary nebula (CSPN) can be revealed by the presence of P Cygni profiles of high-excitation lines overimposed on its stellar continuum. We examined the entire Far-Ultraviolet Spectroscopic Explorer (FUSE) archive and merged all useful spectroscopic observations of CSPNe to produce the high…
Complete Infrared Spectral Energy Distributions of Millimeter Detected Quasars at z > 5
Meisenheimer, K.; Walter, F.; Krause, O. +7 more
We present Herschel far-infrared (FIR) photometry of 11 quasars at redshift z > 5 that have previously been detected at 1.2 mm. We perform full spectral energy distribution (SED) fits over the wavelength range λrest ~ 0.1-400 µm for those objects with good Herschel detections. These fits reveal the need for an additional FIR co…
Herschel-ATLAS/GAMA: a difference between star formation rates in strong-line and weak-line radio galaxies
Cooray, A.; Hardcastle, M. J.; De Zotti, G. +25 more
We have constructed a sample of radio-loud objects with optical spectroscopy from the Galaxy and Mass Assembly (GAMA) project over the Herschel Astrophysical Terahertz Large Area Survey (Herschel-ATLAS) Phase 1 fields. Classifying the radio sources in terms of their optical spectra, we find that strong-emission-line sources (`high-excitation radio…
Magnetic Energy Partition between the Coronal Mass Ejection and Flare from AR 11283
Feng, L.; Inhester, B.; Gan, W. Q. +4 more
On 2011 September 6, an X-class flare and a halo coronal mass ejection (CME) were observed from Earth erupting from the same active region AR 11283. The magnetic energy partition between them has been investigated. SDO/HMI vector magnetograms were used to obtain the coronal magnetic field using the nonlinear force-free field (NLFFF) extrapolation …