Day 757

Friday.  Saturday.

1410.0015
Universality of dark matter haloes shape over six decades in mass: insights from the Millennium XXL and SBARBINE simulations
Bonamigo, et al

Aim to provide the first statistically significant predictions of triaxiality in the unexplored mass range above 3e14 Msun/h, using haloes from z=0 and 1 from the Millennium simulation.  Extend investigation to lower masses in order to look for universal predictions across 6 orders of magnitude in mass, from 1e10 to almost 1e16 Msun/h.  Use an elliptical over density method to select haloes and compute the shapes of the unimodal ones (~50%), while discarding the unrelaxed.  The minor to major and intermediate to major axis ratio are found to be well described by simple functional forms.  For a given mass, can fully characterize the shape of a halo and give predictions about the distribution of axis ratios for a given cosmology and redshift.  These results are in some disagreement with the findings with Jing & Suto (2002) which are widely used in the community even though they need to be extrapolated far beyond their original mass range.  This "recipe" is available to the public.

1409.2885
Crowded Cluster Cores: Algorithms for deblending in Dark Energy Survey images
Zhang, McKay, Bertin, et al

New software, Gradient And Interpolation based deblender (GAIN) as a secondary deblender to improve deblending the images of cluster cores.  Relies on using image intensity gradient and using an image interpolation technique usually used to correct flawed terrestrial digital images.  Test this software on DES coadds.  GAIN helps extracting unbiased photometry measurement for blended sources.  It also helps improving detection completeness while introducing only a modest amount of spurious detections.  For example, when applied to deep images simulated with high level of deblending difficulties, this software improves detection completeness from 91% to 97% for sources above the 10 sigma limiting magnitude at 25.3 mag.  Expect this software to be a useful tool for cluster population measurements.

1409.2951
Ages of Type Ia supernovae over cosmic time
Childress, Wolf, Zahid

Their models reproduce the SN Ia rate evolution in z, the relationship between SN Ia stretch and host mass, and the distribution of SN Ia host masses in a manner qualitatively consistent with observations.  Also naturally predicts that low-mass galaxies tend to be actively SF while massive galaxies are generally passive, consistent with observations of galaxy "downsizing".  Consequently, the mean ages of SNe Ia undergo a sharp transition from young ages at low host mass to old ages at high host mass, qualitatively similar to the transition of mean SN Ia Hubble residuals with host mass.  The age discrepancy evolves with z in a manner currently not accounted for in SN Ia cosmology analyses.  Thus suggest that SNe Ia selected only from actively SF galaxies will yield the most cosmologically uniform sample, due to the homogeneity of young SN Ia progenitor ages at all cosmological epochs.

1410.0363
ExELS: an exoplanet legacy science proposal for the ESA Euclid mission.  II.  Hot exoplanets and sub-stellar systems
McDonald, et al

Combined microlensing+transit survey will allow self-consistent estimate of the relative frequencies of hot and cold sub-stellar companions.  The age of the Bulge and its spread in metallicity allows ExELS to better constrain both the variation of companion frequency with metallicity and statistically explore the strength of star-planet tides.  Conservatively estimate that it will detect ~4100 sub-stellar objects down to Neptune-mass planets.  ~600 detectable in both VIS and HISP with ~90% being hot Jupiters.  Likely find 2900-7000 objects for VIS and 400-1600 for H-band.  Twice as many can be expected in VIS if the cadence can be increase to match the 20-minute H-band cadence.  The separation of planets from brown dwarfs via Doppler boosting or ellipsoidal variability will be possible in a handful of cases.  Radial velocity confirmation should be possible in some cases, using 30-m class telescopes.  Expect secondary eclipses, and reflection and emission from planets to be detectable in up to ~100 systems in both VIS and NISP-H.  Transits of ~500 planetary-radius companions will be characterized with 2-color photometry and ~40 with four-color photometry (VIS, YJH), and the albedo of (and emission from) a large sample of hot Jupiters in the H-band can be explored statistically.