Search Publications
Hydrocarbon ions in the lower ionosphere of Saturn
Moses, J. I.; Black, J. H.; Kim, Y. H. +1 more
Radio occultation measurements of the Saturn ionosphere have shown that persistent but variable electron density layers appear well below the major peaks. We model here the region of hydrocarbon ions that is below the main peak and is produced by absorption of solar photons in the wavelength range 842 to 1116 Å, which penetrate to altitudes below …
Current status of modified gravity
Mena, Olga; Boubekeur, Lotfi; Ramírez, Héctor +1 more
We revisit the cosmological viability of the Hu-Sawicki modified gravity scenario. The impact of such a modification on the different cosmological observables, including gravitational waves, is carefully described. The most recent cosmological data, as well as constraints on the relationship between the clustering parameter σ8 and the c…
The Inside-out Growth of the Most Massive Galaxies at 0.3 < z < 0.9
Gladders, M. D.; Yee, H. K. C.; Yan, Renbin +7 more
We study the surface brightness profiles of a sample of brightest cluster galaxies (BCGs) with 0.3 < z < 0.9. The BCGs are selected from the first Red-sequence Cluster Survey and an X-ray cluster survey. The surface brightness profiles of the BCGs are measured using HST ACS images, and the majority of them can be well modeled by a single Sér…
A Delayed Transition to the Hard State for 4U 1630-47 at the End of its 2010 Outburst
Kaaret, Philip; Yamaoka, Kazutaka; Kalemci, Emrah +3 more
Here we report on Swift and Suzaku observations near the end of an outburst from the black hole transient 4U 1630-47 and Chandra observations when the source was in quiescence. 4U 1630-47 made a transition from a soft state to the hard state ~50 days after the main outburst ended. During this unusual delay, the flux continued to drop, and one Swif…
Infrared absorption by pure CO2 near 3340 cm-1: Measurements and analysis of collisional coefficients and line-mixing effects at subatmospheric pressures
Daneshvar, L.; Földes, T.; Buldyreva, J. +1 more
High resolution Fourier transform spectra of the 21102-00001 band of 12C16O2 near 3340 cm-1 have been recorded and analyzed to extract isolated-line intensities and collisional parameters, and first-order line-mixing coefficients. Voigt, hard-collision Rautian and Sobel'man, and quadratic-speed-dependent…
The case against large intensity fluctuations in the z ∼ 2.5 He II Lyα forest
McQuinn, Matthew; Worseck, Gabor
Previous studies of the 2.2 < z < 2.7 He II Lyα forest measured much larger ionizing background fluctuations than are anticipated theoretically. We re-analyse recent Hubble Space Telescope data from the two He II sightlines that have been used to make these measurements, HE 2347-4342 and HS 1700+6416, and find that the vast majority of the a…
A non-monotonic eddy diffusivity profile of Titan's atmosphere revealed by Cassini observations
Kammer, Joshua A.; Zhang, Xi; Li, Cheng +3 more
Recent measurements from the limb-view soundings of Cassini/CIRS and the stellar occultations from Cassini/UVIS revealed the complete vertical profiles of minor species (e.g., C2H2 and C2H4) from 100 to 1000 km in the atmosphere of Titan. In this study, we developed an inversion technique to retrieve the…
Transmission of large-amplitude ULF waves through a quasi-parallel shock at Venus
Zhang, Tielong; Wang, Shui; Huang, Can +4 more
There exist large-amplitude ultralow frequency (ULF) waves in the upstream region of a quasi-parallel shock, which are excited due to the reflected ions by the shock. These waves are then brought back to the shock by the solar wind, and at last they coalesce and merge with the shock. In this paper, with the magnetic field measurements from Venus E…
First experimental constraints on the disformally coupled Galileon model
Möller, A.; Astier, P.; Conley, A. +6 more
Aims: The Galileon model is a modified gravity model that can explain the late-time accelerated expansion of the Universe. In a previous work, we derived experimental constraints on the Galileon model with no explicit coupling to matter and showed that this model agrees with the most recent cosmological data. In the context of braneworld cons…
A phenomenological model of Io's UV aurora based on HST/STIS observations
Saur, Joachim; Roth, Lorenz; Feldman, Paul D. +2 more
We have carried out a comprehensive analysis of a large set of spatially resolved observations of Io's OI 1304 Å, OI] 1356 Å, SI 1479 Å and SI] 1900 Å aurora taken by the Space Telescope Imaging Spectrograph (STIS) of the Hubble Space Telescope (HST) between 1997 and 2001. We find that the variability of the observed morphologies can be solely exp…