Day 785

Thursday.

1411.1758
Where do the 3.5 keV photons come from?  A morphological study of the galactic center and of Perseus
Carlson, Jeltema, Profumo

Test the origin of the 3.5 keV line photons by analyzing the morphology of the emission at that energy from the GC and from the Perseus cluster of galaxies.  Employ a variety of different templates to model the continuum emission and analyze the resulting radial and azimuthal distribution of the residual emission.  Then perform a pixel-by-pixel binned likelihood analysis including line emission templates and dark matter templates and assess the correlation of the 3.5 keV emission with these templates.  Conclude that the radial and azimuthal distribution of the residual emission is incompatible with the DM origin for both the Galactic center and Perseus; the Galactic center 3.5 keV line photons trace the morphology of lines at comparable energy, while the Perseus 3.5 keV photons are highly correlated with the cluster's cool core, and exhibit a morphology incompatible with either DM decay or with axion-like particle conversions in the cluster's B-fields.  The template analysis additionally allows to set the most stringent constraints to date on lines in the 3.5 keV range from DM decay.

1411.2552
The first light of Mini-MegaTORTORA wide-field monitoring system
Biryukov et al

Describe the first light of the novel 9-channel wide-field optical monitoring system with sub-second temporal resolution, Mini-MegaTORTORA, which is being tested now at Special Astrophysical Observatory on Russian Caucasus.  The system is able to observe the sky simultaneously in either wide (~900 sq deg) or narrow (~100 sq deg) FoV, either in clear light or with any combination of color (Johnson B,V or R) polarimetric filters installed, with exposure times ranging from 100 ms to 100 s.  The primary goal of the system is the detection of rapid - with sub-second characteristic time-scales - optical transients, but it may be also used for studying the variability of the sky objects on longer time scales.

1411.1511
Galaxy groups
Tully

Galaxy groups can be characterized by the radius of decoupling from cosmic expansion, the radius of the caustic of second turnaround, and the velocity dispersion of galaxies within this latter radius.  These parameters can be a challenge to measure, especially for small groups with few members.  In this study, results are gathered pertaining to particularly well studied groups over four decades in group mass.  Scaling relations anticipated from theory are demonstrated and coefficients of the relationships are specified.  There is an update of the relationship between light and mass for groups, confirming that groups with mass of a few times 1e12 Msun are the most lit up while groups with more and less mass are darker.  It is demonstrated that there is an interesting one-to-one correlation between the number of dwarf satellites in a group and the group mass.  There is the suggestion that small variations in the slope of the luminosity function in groups are caused by the degree of depletion of intermediate luminosity systems rather than variations in the number per unit mass of dwarfs.  Finally, returning to the characteristic radii of groups, the ratio of first to second turnaround depends on the DM and DE content of the universe and a crude estimate can be made from the current observations of Omega_m ~0.15 in a flat topology, with a 68% probability of being less than 0.44.

1411.2970
Anomalous coupling of the small-scale structures to the large-scale gravitational growth
Nishimichi, Bernardeau, Taruya

Present the first measurement of NL response of the PS to small variations n the linear counterpart in the context of cosmological LSS formation.  While the mode-coupling structure can be explained to a large extent with the standard perturbation theory, show that the coupling of the short-wave modes are however significantly damped away making them contribute only weakly to the growth of long-wave modes.  This is the first time such an effect is measured.  It is of crucial importance for the use of large-scale cosmological data as probes of fundamental cosmological or physical parameters.

1411.2971
A simple physical model for the gas distribution in galaxy clusters
Patej, Loeb

The dominant baryonic component of galaxy clusters is hot gas whose distribution is commonly probed through X-ray emission arising from thermal bremsstrahlung.  The density profile thus obtained has been traditionally modeled with a beta-profile, a simple function with only 3 parameters.  However, this model is known to be insufficient for characterizing the range of cluster gas distributions, and attempts to rectify this shortcoming typically introduce additional parameters to increase the fitting flexibility.  Use cosmological and physical considerations to obtain a family of profiles for the gas with fewer parameters than the beta-model but which better accounts for observed gas profiles over wide radial intervals.

1411.2976
The galaxy luminosity function at z~6 and evidence for rapid evolution in the bright end from z~7 to 5
Bowler, et al

266 bright Ly-break galaxies at 5.5<z<6.5 in COSMOS and UDS fields:  At z~6 the galaxy surface density in the UltraVISTA field exceeds that in the UDS by a factor of ~1.8, indicating strong cosmic variance been between degree-scale fields at z>5.  Calculate the bright end of the rest-farm UV LF at z~6.  The galaxy number counts are a factor of 2 lower than predicted by the recent LF determination by Bowens+.  In comparison to other smaller area studies, find an evolution in the characteristic magnitude between z~5 and z~7 of dM*~0.4 mag, and show that a double power-law or a Schechter function can equally well describe the LF at z=6.  Furthermore, the bright end of the LF appears to steepen from z~7 to z~5, which could indicate the onset of mass quenching or the rise of dust obscuration, a conclusion supported by comparing the observed LFs to a range of theoretical model predictions.

1411.3193
Hopfield neural network deconvolution for weak lensing measurement
Nurbaeva, Tewes, Courbin, Meylan

Present a new method to measure the ellipticity of galaxies used in WL surveys.  The method makes use of direct deconvolution of the data by the total PSF.  Adopt a linear algebra formalism that represents the PSF as a Toeplitz matrix.  This allows to solve the convolution equation by applying the HNN iterative scheme.  The ellipticity of galaxies in the deconvolved images are then measured using second order moments of the autocorrelation function of the images.  This is the first time full image deconvolution is used to measure WL shear.  Apply method to the simulated WL data proposed in the GREAT10 challenge and obtain Q=87.  This result is obtained after applying image denoting to the data, prior to the deconvolution.  The additive and multiplicative biases on the shear PS are then 0.000009 and 0.0357, respectively.