Sunday. Bonn didn't get Excellence Cluster. Schade!
1206.2348
Structure formation in multiple dark matter cosmologies with long-range scalar interactions
Baldi
Interaction between CDM and a DE scalar field might provide long-range dark interactions without conflicting with solar system bounds. If CDM is composed of two different particle species having opposite couplings to the DE field, tight constraints from solar system observation can be relaxed, allowing for long-range scalar forces of order gravity both at the background and at the linear perturbations level. Extend multiple DM studies to NL, by presenting N-body simulations. Formation of "mirror" socmic structures in the two CDM species, suppression of the nonlinear matter power spectrum at k>1h/Mpc, and fragmentation of collapsed haloes represent peculiar features that might constrain this class of cosmological models.
1206.2350
Hydrodynamical simulations to determine the feeding rate of black holes by the tidal disruption of stars: the importance of the impact parameter and stellar structure
Guillochon, Ramirez-Ruiz
Model disruption of stars by SMBH, show that common assumptions used to estimate dM/dt(t), the rate of mass return to BH, are largely invalid. Find most-centrally concentrated stars have the quickest-peaking flares, vs. analytical approximation to tidal disruption predicts that the least-centrally concentrated stars and the deepest encounters should have more quickly-peaked flares.
1206.2355
Irregular sloshing cold fronts in the nearby merging groups NGC 7618 and UGC 12491: evidence for Kelvin-Helmholtz instabilities
Roediger et al
Chandra observation (30 ks each) show hot atmospheres of the merging galaxy groups; show the presence of arc-like sloshing cold fronts wrapped around each group center and ~100 kpc long spiral tails in both groups. Cold fronts are highly distorted in both groups, exhibiting 'wings' along the fronts, resembling structures predicted from non-viscous KHIs distort the cold fronts (in contrast to other observed smooth fronts). B-fields and/or viscosity may suppress growth of KHIs, but not in all. Propose KHI-distortion existence in cold fronts can be used as a measure of the effective viscosity and/or magnetic filed strengths in the ICM.
1206.2357
A complete sample of bright Swift Gamma-ray bursts: X-ray afterglow luminosity and its correlation with the prompt emission
D'Avanzo et al
From a purely flux-limited GRBs nearly complete (~90%) in redshift, show that X-ray afterglow of GRBs (5min, 1hr, 11hr and 24hr) and GRB prompt emission energy E_iso correlate. Find: plateau and shallow decay phase in X-ray are powered by activity from the central engine.
1206.2359
Dark satellites and the morphology of dwarf galaxies
Helmi et al
Dynamical effects of dark satellites orbiting around disk dwarf galaxies, frequent (due to their sizes), encounters are dramatic. Example: dark satellite and disky dwarf results in spheroidal morphology by perturbations by dark satellites.
1206.2360
Newborn spheroids at high redshift: when and how did the dominant, old stars in today's massive galaxies form?
Kaviraj et al
Empirical study indicates that processes other than major mergers (e.g., violent disk instability driven by cold streams and/or minor mergers) likely play a dominant role in building SGs, and creating the old stellar populations that dominate today's Universe.
1206.2367
Planetary evaporation by UV & X-ray radiation: basic hydrodynamics
Owen, Jackson
Planetary evaporation is more important for lower mass planets (hot Neptune/suer Earth).
1206.2370
Herschel imaging of 61 Vir: implications for the prevalence of debris in low-mass planetary systems
Wyatt et al
Debris disk around a nearby star with multiple exoplanets. [hard to see from the images in the paper] Tentative evidence that the presence of detectable debris around nearby stars correlates with the presence of the lowest mass planets that are detectable in current radial velocity surveys.
1206.2374
Observed luminosity spread in young clusters and Fu Ori stars: a united picture
Baraffe, Vorobyov, Chabrier
Non-steady accretion of collapsing cloud prestellar cores of various masses and subsequent protostar evolution simulations show: both the luminosity spread in the HRD and the inferred properties of Fu Ori events (mass, radius, accretion rate) can be explained by this scenario, if there is variation of energy absorbed by the protostar during accretion, and range of such variation increasing with increasing accretion burst intensity, and thus with the initial core mass and final star mass. Suggests a link between the burst intensities and the fraction of accretion energy absorbed by the protostar.
1206.2375
Angular fluctuations in the CXB: Is Fe 6.4 keV line tomography of the large-scale structure feasible?
Hütsi, Gilfanov, Sunyaev
CXB primarily due to AGN, and the dominant sharp feature is the 6.4 keV fluorescent line of Fe (contribute as much as ~5-10% of the CXB spectral intensity at 2-6 keV). Extract LSS information from Fe lines: Fe K_alpha line tomography of LSS. This requires 10m^2 area mirror and 1 deg^2 FoV. Signal strongest at z~1 and ell~100-300, which requires angular resolution of 0.1-0.5 deg. 100-300 eV FWHM resolution sufficient, achieved by CCDs. Clear detection by WFXT and ATHENA, but 4-year eROSITA all-sky will detect the tomographic signal marginally.
No comments:
Post a Comment