Search Publications
The 1.4-GHz radio properties of hard X-ray-selected AGN
Bird, A. J.; Ubertini, P.; Malizia, A. +7 more
We have analysed the NRAO Very Large Array Sky Survey and Sydney University Molonglo Sky Survey data at 1.4 GHz and 843 MHz for a well-defined complete sample of hard X-ray AGN observed by INTEGRAL. A large number (70/79) of sources are detected in the radio band, showing a wide range of radio morphologies, from unresolved or slightly resolved cor…
Benchmark stars for Gaia Fundamental properties of the Population II star HD 140283 from interferometric, spectroscopic, and photometric data
Morel, P.; Berio, P.; Meilland, A. +18 more
Metal-poor halo stars are important astrophysical laboratories that allow us to unravel details about many aspects of astrophysics, including the chemical conditions at the formation of our Galaxy, understanding the processes of diffusion in stellar interiors, and determining precise effective temperatures and calibration of colour-effective tempe…
Properties of solar energetic particle events inferred from their associated radio emission
Valtonen, E.; Hillaris, A.; Malandraki, O. +6 more
Aims: We study selected properties of solar energetic particle (SEP) events as inferred from their associated radio emissions.
Methods: We used a catalogue of 115 SEP events, which consists of entries of proton intensity enhancements at one AU, with complete coverage over solar cycle 23 based on high-energy (~68 MeV) protons from SOHO/ER…
Cooling of the Martian thermosphere by CO2 radiation and gravity waves: An intercomparison study with two general circulation models
Medvedev, Alexander S.; Yiǧit, Erdal; Hartogh, Paul +3 more
Observations show that the lower thermosphere of Mars (∼100-140 km) is up to 40 K colder than the current general circulation models (GCMs) can reproduce. Possible candidates for physical processes missing in the models are larger abundances of atomic oxygen facilitating stronger CO2 radiative cooling and thermal effects of gravity wave…
Six years of Venus winds at the upper cloud level from UV, visible and near infrared observations from VIRTIS on Venus Express
Hueso, R.; Sánchez-Lavega, A.; Peralta, J. +2 more
The Venus Express mission has provided a long-term monitoring of Venus atmosphere including the morphology and motions of its upper clouds. Several works have focused on the dynamics of the upper cloud visible on the day-side in ultraviolet images sensitive to the 65-70 km altitude and in the lower cloud level (50 km height) observable in the nigh…
Dust devil height and spacing with relation to the martian planetary boundary layer thickness
Fenton, Lori K.; Lorenz, Ralph
In most remote and unmonitored places, little is known about the characteristics of daytime turbulent activity. Few processes render the optically transparent atmospheres of Earth and Mars visible; put more plainly, without clever instruments it is difficult to "see the unseen". To address this, we present a pilot study of images of martian dust d…
An Ultrasoft X-Ray Flare from 3XMM J152130.7+074916: A Tidal Disruption Event Candidate
Gwyn, Stephen D. J.; Komossa, S.; Lin, Dacheng +6 more
We report on the discovery of an ultrasoft X-ray transient source, 3XMM J152130.7+074916. It was serendipitously detected in an XMM-Newton observation on 2000 August 23, and its location is consistent with the center of the galaxy SDSS J152130.72+074916.5 (z = 0.17901 and dL = 866 Mpc). The high-quality X-ray spectrum can be fitted with…
Hard X-Ray Morphological and Spectral Studies of the Galactic Center Molecular Cloud Sgr B2: Constraining Past Sgr A* Flaring Activity
Hailey, Charles J.; Mori, Kaya; Bauer, Franz E. +15 more
In 2013, NuSTAR observed the Sgr B2 region and for the first time resolved its hard X-ray emission on subarcminute scales. Two prominent features are detected above 10 keV: a newly emerging cloud, G0.66-0.13, and the central 90″ radius region containing two compact cores, Sgr B2(M) and Sgr B2(N), surrounded by diffuse emission. It is inconclusive …
Polyspectra searches for sharp oscillatory features in cosmic microwave sky data
Shellard, E. P. S.; Fergusson, J. R.; Gruetjen, H. F. +1 more
Despite numerous efforts, the search for oscillatory signatures in primordial spectra has not produced any convincing evidence for feature models to date. We undertake a thorough search for signatures of sharp features in the WMAP9 power spectrum and bispectrum as well as in the Planck power spectrum. For the first time, we carry out searches in b…
Evidence of Cross-correlation between the CMB Lensing and the γ-Ray Sky
Fornengo, Nicolao; Perotto, Laurence; Regis, Marco +1 more
We report the measurement of the angular power spectrum of cross-correlation between the unresolved component of the Fermi-LAT γ-ray sky maps and the cosmic microwave background lensing potential map reconstructed by the Planck satellite. The matter distribution in the universe determines the bending of light coming from the last scattering surfac…