Search Publications
Probing quiet Sun magnetism using MURaM simulations and Hinode/SP results: support for a local dynamo
Solanki, S. K.; Danilovic, S.; Schüssler, M.
Context. Owing to the limited spatial resolution and the weak polarization signal coming from the quietest regions on the Sun, the organization of the magnetic field on the smallest scales is largely unknown.
Aims: We obtain information about the magnetic flux present in the quiet Sun by comparing radiative MHD simulations with observations, …
Characteristics of Solar Meridional Flows during Solar Cycle 23
Basu, Sarbani; Antia, H. M.
We have analyzed available full-disk data from the Michelson Doppler Imager on board SOHO using the "ring diagram" technique to determine the behavior of solar meridional flows over solar cycle 23 in the outer 2% of the solar radius. We find that the dominant component of meridional flows during solar maximum was much lower than that during the mi…
Exploring the physical properties of local star-forming ULIRGs from the ultraviolet to the infrared
Elbaz, D.; Armus, L.; da Cunha, E. +3 more
We apply the da Cunha et al. (2008, MNRAS, 388, 1595) model of the spectral energy distribution (SEDs) of galaxies to a small pilot sample of purely star-forming ultra-luminous infrared galaxies (ULIRGs). We interpret the observed SEDs of 16 ULIRGs using this physically-motivated model that accounts for both the emission of stellar populations fro…
A High-resolution Mass Map of Galaxy Cluster Substructure: LensPerfect Analysis of A1689
Broadhurst, Tom; Coe, Dan; Benítez, Narciso +1 more
We present a strong lensing (SL) mass model of A1689 which resolves substructures an estimated 25 kpc across within the central ~400 kpc diameter. We achieve this resolution by perfectly reproducing the observed (strongly lensed) input positions of 168 multiple images of 55 knots residing within 135 images of 42 galaxies. Our model makes no assump…
Detection of a magnetic field on HD108: clues to extreme magnetic braking and the Of?p phenomenon
Bouret, J. -C.; Martins, F.; Donati, J. -F. +5 more
We report the detection of a magnetic field on the Of?p star HD108. Spectropolarimetric observations conducted in 2007, 2008 and 2009, respectively, with NARVAL@Télescope Bernard Lyot (TBL) and Echelle SpectroPolarimetric Device for the Observation of Stars at Canada-France-Hawaii Telescope (ESPaDOnS@CFHT) reveal a clear Zeeman signature in the av…
Alfvén-wave Turbulence and Perpendicular Ion Temperatures in Coronal Holes
Chandran, Benjamin D. G.
Low-frequency Alfvén-wave turbulence causes ion trajectories to become chaotic, or "stochastic," when the turbulence amplitude is sufficiently large. Stochastic orbits enable ions to absorb energy from the turbulence, increasing the perpendicular ion temperature T bottomi even when the fluctuation frequencies are too small for a cyclotr…
Total Solar Eclipse Observations of Hot Prominence Shrouds
Rušin, V.; Druckmüller, M.; Morgan, H. +5 more
Using observations of the corona taken during the total solar eclipses of 2006 March 29 and 2008 August 1 in broadband white light and in narrow bandpass filters centered at Fe X 637.4 nm, Fe XI 789.2 nm, Fe XIII 1074.7 nm, and Fe XIV 530.3 nm, we show that prominences observed off the solar limb are enshrouded in hot plasmas within twisted magnet…
Distance determination for RAVE stars using stellar models . II. Most likely values assuming a standard stellar evolution scenario
Gilmore, G.; Freeman, K. C.; Munari, U. +23 more
The RAdial Velocity Experiment (RAVE) is a spectroscopic survey of the Milky Way which already collected over 400 000 spectra of ~ 330 000 different stars. We use the subsample of spectra with spectroscopically determined values of stellar parameters to determine the distances to these stars. The list currently contains 235 064 high quality spectr…
Collisional spreading of Enceladus’ neutral cloud
Johnson, R. E.; Cassidy, T. A.
We describe a direct simulation Monte Carlo (DSMC) model of Enceladus' neutral cloud and compare its results to observations of OH and O orbiting Saturn. The OH and O are observed far from Enceladus (at 3.95 R S), as far out as 25 R S for O. Previous DSMC models attributed this breadth primarily to ion/neutral scattering (inc…
A Tidal Disruption Flare in A1689 from an Archival X-ray Survey of Galaxy Clusters
Eracleous, Michael; Maksym, W. Peter; Ulmer, M. P.
Theory suggests that a star making a close passage by a supermassive black hole at the center of a galaxy can under most circumstances be expected to emit a giant flare of radiation as it is disrupted and a portion of the resulting stream of shock-heated stellar debris falls back onto the black hole itself. We examine the first results of an ongoi…