Search Publications
A Comprehensive Investigation on the Slowing Down of Cosmic Acceleration
Li, Nan; Li, Miao; Wang, Shuang +1 more
Shafieloo et al. first proposed the possibility that the current cosmic acceleration (CA) is slowing down. However, this is rather counterintuitive because a slowing down CA cannot be accommodated in most mainstream cosmological models. In this work, by exploring the evolutionary trajectories of the dark energy equation of state w(z) and decelerat…
Rotational modulation of Saturn's radio emissions after equinox
Gurnett, D. A.; Kurth, W. S.; Ye, S. -Y. +2 more
Saturn kilometric radiation (SKR), narrowband emission, and auroral hiss are periodically modulated due to Saturn's rotation, and the periods were found to vary with time. We analyze Cassini observations of Saturn's radio emissions with the main focus on the four years 2012-2015. It is shown that the rotation rates of SKR north and south were diff…
Empirically Constrained Predictions for Metal-line Emission from the Circumgalactic Medium
Schiminovich, David; Corlies, Lauren
The circumgalactic medium (CGM) is one of the remaining least constrained components of galaxies and as such has significant potential for advancing galaxy formation theories. In this work, we vary the extragalactic ultraviolet background for a high-resolution cosmological simulation of a Milky-Way-like galaxy and examine the effect on the absorpt…
An HST Proper-motion Study of the Large-scale Jet of 3C273
Anderson, Jay; Sparks, William B.; Georganopoulos, Markos +7 more
The radio galaxy 3C 273 hosts one of the nearest and best-studied powerful quasar jets. Having been imaged repeatedly by the Hubble Space Telescope (HST) over the past twenty years, it was chosen for an HST program to measure proper motions in the kiloparsec-scale resolved jets of nearby radio-loud active galaxies. The jet in 3C 273 is highly rela…
Detail studies of the physical properties in the outer regions of galaxy clusters using Suzaku observations
Babyk, Iu. V.
A detailed physical analysis of five nearby galaxy clusters using Suzaku observationsis presented. The low and stable level of the instrumental background at large radii facilitate the determination of the main physical characteristics in clusters at the virial radius. The temperatures, metal abundances, and entropy profiles have been constructed …
H I-deficient galaxies in intermediate-density environments
Koribalski, B. S.; Dénes, H.; Wong, O. I. +1 more
Observations show that spiral galaxies in galaxy clusters tend to have on average less neutral hydrogen (H I) than galaxies of the same type and size in the field. There is accumulating evidence that such H I-deficient galaxies are also relatively frequent in galaxy groups. An important question is that which mechanisms are responsible for the gas…
A sedimentary origin for intercrater plains north of the Hellas basin: Implications for climate conditions and erosion rates on early Mars
Mangold, Nicolas; Ori, Gian Gabriele; Salese, Francesco +4 more
Understanding the origin (volcanic or sedimentary) and timing of intercrater plains is crucial for deciphering the geological evolution of Mars. We have produced a detailed geological map of the intercrater plains north of the Hellas basin, based on images from the Mars Express High-Resolution Stereo Camera, the Mars Reconnaissance High-Resolution…
The panchromatic spectroscopic evolution of the classical CO nova V339 Delphini (Nova Del 2013) until X-ray turnoff
Buil, C.; Scaringi, S.; Shore, S. N. +10 more
Context. Classical novae are the product of thermonuclear runaway-initiated explosions occurring on accreting white dwarfs.
Aims: V339 Del (Nova Delphinus 2013) was one of the brightest classical novae of the last hundred years. Spectroscopy and photometry are available from γ-rays through infrared at stages that have frequently not been obse…
Ion Acceleration at the Quasi-parallel Bow Shock: Decoding the Signature of Injection
Burgess, D.; Sundberg, Torbjörn; Haynes, Christopher T. +1 more
Collisionless shocks are efficient particle accelerators. At Earth, ions with energies exceeding 100 keV are seen upstream of the bow shock when the magnetic geometry is quasi-parallel, and large-scale supernova remnant shocks can accelerate ions into cosmic-ray energies. This energization is attributed to diffusive shock acceleration however, for…
The impact of the SZ effect on cm-wavelength (1-30 GHz) observations of galaxy cluster radio relics
Vazza, Franco; Basu, Kaustuv; Erler, Jens +1 more
Radio relics in galaxy clusters are believed to be associated with powerful shock fronts that originate during cluster mergers, and are a testbed for the acceleration of relativistic particles in the intracluster medium. Recently, radio relic observations have pushed into the cm-wavelength domain (1-30 GHz) where a break from the standard synchrot…