1108.4411
Ultra-fine dark matter structure in the Solar neighbourhood
Fantin, Green, Merrifield
* how many parsecs to an AU? ... must be 3600 (or off by a factor of 2, depending on the defn). ...Actually, it's 206265 AU in a parsec. (1) I forgot about 360 degrees, and (2) to convert degrees to radians. 1 parsec is the distance to an object that moves 2 arcsec in 6 months (corresponds to 1arcsec movement for 1 AU).
Direct detection of DM on Earth depends on density and velocity distribution on milliparsec scale. Use cosmological merger tree to analyze the merger history of a MW-like system, to investigate the implications of any ultra-fine structure for direct DM detectors. Find velocity distribution of MW-like galaxy is almost smooth, due to overlap of many streams of particles generated by multiple mergers. Only mergers of 1e10M_sun can generate significant features in the ultra-local velocity distribution which can be detectable by current experiments.
* but how about seasonal variations, that are used in some of the DM detection experiments?
1108.4681
The serendipitous observation of a gravitationally lensed galaxy at z=0.9057 from the Blanco Cosmology Survey: The Elliot Arc
Buckley-Geer, Drabeck... YT Lin... A Rest, et al
Optical Blanco Cosmology Survey (BCS) found a high-z galaxy lensed by a massive galaxy cluster at z=0.3838. Confirmed with spectro with GMOS on 8m Gemini South. Use WL+SL, velocity dispersion, cluster richness N_200, fitting to an NFW cluster mass density profile: 3 independent mass estimates of the mass M_200 that are consistent with each other: 5.1 pm 1.3 e14 M_sun. NFW concentration c_200 = 5.4 (+1.4-1.1). Compare with LCDM sim, lensing selected clusters, and real sample of cluster lenses. Most are compatible for LCDM for lensing clusters. No evidence based on one system for an increased concentration compared to LCDM. Determine SFR measured from OII 3727 line, and find it to be modest for the given lens magnification.
1108.4136
Sterile neutrions with eV masses in cosmology -- how disfavoured exactly?
Hamann, Hannestad, Raffelt, Wong
In the minimal LCDM model, eV sterile neutrios strongly disfavoured because they contribute too much hot dark matter. However, if the LCDM model is extended to include additional degrees of freedom in addition to the sterile neutrinos, then the HDM constraint on sterile states i considerably relaxed. Further improvement with w<-1. BBN strongly disfavours extra radiation beyond the assumed eV-mass sterile neutrino, but this can be circumvented by a small nu_e degeneracy. Any model containing eV-mass sterile neutrinos implies strong modifications of other cosmological parameters: the inferred CDM density can shift up by 20 to 75% relative to the standard LCDM value.
* so this seems rather unlikely?
1108.4173
Vector dark energy and high-z massive clusters
Carlesi, Knebe, Yepes, Gottloeber, Jimenez, Maroto
Detection of extremely massive clusters at z>1 has been considered by some authors as a challenge to the standard LCDM cosmology. Discuss probability of existence of such objects in light of the Vector Dark Energy (VDE) paradigm, where chances of detection substantially enhanced.
* Maybe a good filament project? check for filaments at high-z, and then check mass biases there.
1108.4314
Galaxy Disks are Submaximal
Bershady, et al
Measure disk contribution of 30 (nearly) face-on spirals from the DiskMass survey. Measure the velocity distribution of disk in the radial and the cylindrical axis direction: sigma(z, R=0) ~ 0.26 Vmax, which is consistent with sigma(z)/siamg(R) = 0.6, implying "submaximal disks". Disks in sample contribute only 15 to 30% of the dynamical mass within 2.2 disk scale-lengths (hR); percentages increase systematically with luminosity, rotation speed and redder color. Disk-to-total mass ratio is at most 50% even from the fastest rotating galaxies (Vmax > 300 km/s), the reddest rest-frame (B-K~4mag) and highest luminosity (M(K) < -26.5). Spiral disks in general should be maximal. Implies stellar M/L ratio (and hence accounting of baryons in stars) should be lowered by at least a factor of 3.
* I don't understand what it means for spirals to be "submaximal".
1108.3989
Three-Dimensional hydrodynamic core-collapse SNe simulations for an 11.2 M_sun star with spectral neutrino transport
Takiwaki, Kotake, Suwa
Show how the postbounce SNe dynamics are affected with spatial multi-dimensionality (3D sim vs 2D and 1D). Calculate with: energy-dependent treatment of the neutrino transport. Tracer-particle analysis show: maximum residency time of material in the gain region is longer for 3D due to non-axisymmetric flow (vs 2D): advantageous to obtain neutrino-driven explosions. Convective matter motions more violent in 3D, but emitted neutrino energies smaller due to enhanced cooling. Shock expansion tends to become more energetic for models with finer resolutions. 3D sims with higher numerical resolutions and more advanced treatment of neutrino transport and gravity are needed.
1108.4036
The long-term evolution of double white dwarf mergers
Shen, Bildsten, Kasen, Quartaert
Some simulation on two C/O white dwarfs of unequal mass. Should not result in a Type Ia SNe.
1108.2725
X-Ray and optical flux ratio anomalies in quadruply lensed quasars. II. Mapping the DM content in elliptical galaxies
Pooley, Rappaport, Balckburne, Schechter, Wambsganss
61 Chandra observations of 14 quadruply lensed quasars; observe flux ratio in x-ray, which gives clean determination of microlensing effects in the lensing galaxy. Local stellar fraction of 7%, the rest (93%) in a smooth, dark matter component (gas negligible?).
* is ignoring gas a good assumption? That's not true for galaxy clusters, is it?
1108.2842
What can the detection of single pair of circiles-in-the-sky tell us about the geometry and tolopgy of the Universe?
Mota, Reboucas, Tavakol
When the universe is *exactly* flat, then detection of non-trivial spatial topology doesn't have to be through detection of antipodal pairs of circles in the sky.
1108.2914
Exclusion of canonical WIMPs by the joint analysis of MW dwarfs with Fermi
Geringer-Sameth, Koushiappas
Generic WIMP candidates with M<27 GeV excluded.
2208.4128
Dominant Multipoles in WMAP5 Mosaic Data Correlation Maps
Verkhodanov, Khabibullina
ILC (?) map anomaly in the main plane and poles of ecliptic and equatorial coordinate systems. A dominant quadrupole contribution found.
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