Search Publications
Discovery of X-Ray Pulsations from the Next Geminga, PSR J1836+5925
Takata, J.; Kong, A. K. H.; Hui, C. Y. +5 more
We report recent XMM-Newton investigations of PSR J1836+5925, the "next Geminga," which determined an X-ray pulsation of ~173.3 ms. Its X-ray periodicity is consistent with the γ-ray ephemeris at the same epoch. The X-ray folded light curve has a sinusoidal structure that is different from the double-peaked γ-ray pulse profile. We have also analyz…
Mechanisms and timescales of fluvial activity at Mojave and other young Martian craters
Warner, Nicholas H.; Gupta, Sanjeev; Kim, Jung-Rack +1 more
Mojave Crater, and five other relatively young Late Hesperian to Amazonian-age Martian craters exhibit channelized alluvial fans that are sourced from bedrock-eroded catchments. These catchments emerge from the crests of sloping surfaces, suggesting a formation mechanism that involved precipitation. The evidence for fluvial activity at all six cra…
The ionosphere of Saturn as observed by the Cassini Radio Science System
Anabtawi, Aseel; Barbinis, Elias; Fleischman, Don +5 more
Fifty-nine ionsopheric radio occultation observations of the vertical electron density profile in the Saturn ionosphere have been made since the Cassini spacecraft was inserted in orbit around Saturn in 2004. Significant orbit to orbit variations were observed, but the general trend noted in earlier orbits, namely, increasing electron densities wi…
Dependence of Geomagnetic Storms on Their Associated Halo CME Parameters
Moon, Y. -J.; Lee, Kyoung-Sun; Kim, R. -S. +1 more
We compare the geoeffective parameters of halo coronal mass ejections (CMEs). We consider 50 front-side full-halo CMEs (FFH CMEs), which are from the list of Michalek, Gopalswamy, and Yashiro (Solar Phys.246, 399, 2007), whose asymmetric-cone model parameters and earthward-direction parameter were available. For each CME we use its projected veloc…
The important role of evolution in the Planck YSZ-mass calibration
Andreon, S.
In light of the tension between cosmological parameters from Planck cosmic microwave background and galaxy clusters, we revised the Planck analysis of the YSZ-mass calibration to allow evolution to be determined by the data instead of being imposed as an external constraint. Our analysis uses the very same data and Malmquist bias correc…
Accidental inflation from Kähler uplifting
Ben-Dayan, Ido; Jing, Shenglin; Westphal, Alexander +1 more
We analyze the possibility of realizing inflation with a subsequent dS vacuum in the Käahler uplifting scenario. The inclusion of several quantum corrections to the 4d effective action evades previous no-go theorems and allows for construction of simple and successful models of string inflation. The predictions of several benchmark models are in a…
Symbiotic stars in OGLE data - I. Large Magellanic Cloud systems
Udalski, A.; Pietrukowicz, P.; Masetti, N. +10 more
Symbiotic stars are long-orbital-period interacting binaries characterized by extended emission over the whole electromagnetic range and by complex photometric and spectroscopic variability. In this paper, the first of a series, we present Optical Gravitational Lensing Experiment (OGLE) light curves of all the confirmed symbiotic stars in the Larg…
Backward Wave Cyclotron-Maser Emission in the Auroral Magnetosphere
Kellett, B. J.; Vorgul, I.; Bingham, R. +4 more
In this Letter, we present theory and particle-in-cell simulations describing cyclotron radio emission from Earth's auroral region and similar phenomena in other astrophysical environments. In particular, we find that the radiation, generated by a down-going electron horseshoe distribution is due to a backward-wave cyclotron-maser emission process…
Atomic data for astrophysics: improved collision strengths for Fe viii
Del Zanna, G.; Badnell, N. R.
We describe, and present the results of, a new large-scale R-matrix scattering calculation for the electron collisional excitation of Fe viii. We first discuss the limitations of the previous calculations, in particular concerning some strong EUV lines observed in the solar corona by the Hinode EUV Imaging Spectrometer. We then present a new targe…
Relativistic reflection in the average X-ray spectrum of active galactic nuclei in the Véron-Cetty and Véron catalogue
Barcons, X.; Falocco, S.; Miniutti, G. +2 more
Context. The X-ray spectra of active galactic nuclei (AGN) unveil properties of matter around the super-massive black hole (SMBH).
Aims: We investigate the X-ray spectra of AGN focusing on Compton reflection and fluorescence. These are two of the most important processes of interaction between primary radiation and circumnuclear material that…