Day 1026

Thursday.


Special Topics
Search for new physics in high mass diphoton events at ATLAS and CMS
CMS collaboration

Report on a search for new physics using high mass diphoton events.  The search employs 2.6 fb^-1 of pp collision data collected by the CMS experiments in 2015 at sqrt(s)=13 TeV and it is principally aimed at extra dimensional models leading to resonant production of two photons.  Limits on the production cross section of Randal-Sundrum graviton decaying to two photons are obtained in the range 500-4500 GeV.


1512.05095
Degeneracies of parametric lens model families near folds and cusps
Wagner, Bartelmann

Develop an approach to select families of lens models that can describe doubly and triply gravitationally lensed images near folds and cusps using the model-independent ratios of lensing-potential derivatives derived in Wagner & Bartelmann (2015).  Models are selected by comparing these model-independent ratios of potential derivatives to (numerically determined) ratios of potential derivatives along critical curves for entire lens model families in a given range of parameter values.  This comparison returns parameter ranges which lens model families can reproduce observation within, as well as sections of the critical curve where image sets of the observed type can appear.  If the model-independent potential-derivative ratios inferred form the observation fall outside the range of these ratios derived for the lens model family, the entire family can be excluded as a feasible model in the given volume in parameter space.  Employ this approach for the family of singular isothermal spheres with external shear to examples of lensing by a galaxy and two galaxy clusters (JVAS B1422+231, SDSS J222+2745,and MACS J1149.5+2223) and show that the results obtained by the general method are in good agreement with results of previous model fits.


1512.05198
Cosmology with all-sky surveys
Bilicki

Various aspects of cosmo require comprehensive all-sky mapping of the cosmic web to considerable depths.  In order to probe the whole extragalactic sky beyond 100 Mpc, one must draw on multi wavelength datasets and state-of-the-art photometric z techniques.  Summarize the dedicated program that employs the largest photometric all-sky surveys -- 2MASS, WISE and SuperCOSMOS -- to obtain accurate redshift estimates of millions of galaxies.  The first outcome of these efforts -- the 2MASS Photometric Redshift Catalog (2MPZ) -- was publicly release in 2013 and includes almost 1 M galaxies with a median redshift of z~0.1.  Discuss how the catalog was constructed and how it is being used for various cosmo tests.  Also present how combining the WISE mid-IR survey with SuperCOSMOS optical data allows using to depths over 1Gpc on unprecedented angular scales.  These photo-z samples, with about 20M sources in total, provide access to volumes large enough to sugary observationally the Copernican Principle of universal homogeneity and isotropy, as well as to probe various aspects of DE and DM through cross-correlations with other data such as the cosmic microwave or gamma-ray backgrounds.  They constitute a test-bed for forthcoming wide-angle multi-million galaxy samples expected from such instruments as the SKA, Euclid or LSST.