Search Publications
Terrestrial lion roars and non-Maxwellian distribution
Schwartz, S. J.; Yoon, P. H.; Masood, W. +3 more
Lion roars are low-frequency (∼100 Hz) whistler waves frequently observed in the Earth's magnetosheath. By analyzing both wave and electron data from the Cluster spacecraft, and comparing with linear Vlasov kinetic theory, Masood et al. (2006) investigated the underlying cause of the lion roar generation. However, the analysis based upon the bi-Ma…
On helium-dominated stellar evolution: the mysterious role of the O(He)-type stars
Rauch, T.; Werner, K.; Kruk, J. W. +2 more
Context. About a quarter of all post-asymptotic giant branch (AGB) stars are hydrogen-deficient. Stellar evolutionary models explain the carbon-dominated H-deficient stars by a (very) late thermal pulse scenario where the hydrogen-rich envelope is mixed with the helium-rich intershell layer. Depending on the particular time at which the final flas…
The Emergent 1.1-1.7 µm Spectrum of the Exoplanet CoRoT-2b as Measured Using the Hubble Space Telescope
Wilkins, Ashlee N.; Deming, Drake; Madhusudhan, Nikku +4 more
We have used Hubble/WFC3 and the G141 grism to measure the secondary eclipse of the transiting, very hot Jupiter CoRoT-2b in the 1.1-1.7 µm spectral region. We find an eclipse depth averaged over this band equal to 395^{+69}_{-45} parts per million, equivalent to a blackbody temperature of 1788 ± 18 K. We study and characterize several WFC3 …
The Optical, Ultraviolet, and X-Ray Structure of the Quasar HE 0435-1223
Chen, Bin; Kochanek, Christopher S.; Dai, Xinyu +2 more
Microlensing has proved an effective probe of the structure of the innermost regions of quasars and an important test of accretion disk models. We present light curves of the lensed quasar HE 0435-1223 in the R band and in the ultraviolet (UV), and consider them together with X-ray light curves in two energy bands that are presented in a companion…
Oblique electron fire hose instability: Particle-in-cell simulations
Hellinger, Petr; Trávníček, Pavel M.; Decyk, Victor K. +1 more
Nonlinear properties of the oblique resonant electron fire hose instability are investigated using two-dimensional particle-in-cell simulations in the Darwin approximation for weak initial growth rates. The weak electron fire hose instability has a self-destructive nonlinear behavior; it destabilizes a nonpropagating branch which only exists for a…
Searching for large-scale structures around high-redshift radio galaxies with Herschel
Clements, D. L.; De Lucia, G.; Dannerbauer, H. +15 more
This paper presents the first results of a far-infrared search for protocluster-associated galaxy overdensities using the Spectral and Photometric Imaging REciever (SPIRE) instrument on-board the Herschel Space Observatory. Large (∼400 arcmin2) fields surrounding 26 powerful high-redshift radio galaxies (2.0 < z < 4.1; L500 M…
Filamentary star formation in NGC 1275
O'Connell, R. W.; Fabian, A. C.; Gallagher, J. S. +8 more
We examine the star formation in the outer halo of NGC 1275, the central galaxy in the Perseus cluster (Abell 426), using far-ultraviolet and optical images obtained with the Hubble Space Telescope. We have identified a population of very young, compact star clusters with typical ages of a few Myr. The star clusters are organized on multiple kilop…
Evidence for very recent melt-water and debris flow activity in gullies in a young mid-latitude crater on Mars
Hiesinger, H.; Hauber, E.; Johnsson, A. +2 more
Terrestrial debris flows and their deposits are mainly studied and monitored because of their hazardous nature. On Mars they may serve as geomorphologic indicators of transient liquid water. We compared the morphology of debris flow-like deposits within a young (∼0.2 Ma) mid-latitude crater on Mars with debris flow fans on Svalbard as possible ter…
Multiple density discontinuities in the merging galaxy cluster CIZA J2242.8+5301
Simionescu, A.; Croston, J. H.; Brüggen, M. +4 more
CIZA J2242.8+5301, a merging galaxy cluster at z = 0.19, hosts a double-relic system and a faint radio halo. Radio observations at frequencies ranging from a few MHz to several GHz have shown that the radio spectral index at the outer edge of the northern relic corresponds to a shock of Mach number 4.6_{-0.9}^{+1.3}, under the assumptions of diffu…
The dynamics and star-forming potential of the massive Galactic centre cloud G0.253+0.016
Henning, Th.; Beuther, H.; Linz, H. +3 more
Context. The massive infrared dark cloud G0.253+0.016 projected ~45 pc from the Galactic centre contains ~105 M⊙ of dense gas whilst being mostly devoid of observed star-formation tracers.
Aims: Our goals are therefore to scrutinise the physical properties, dynamics and structure of this cloud with reference to its star-…