The existence of non-random galaxy intrinsic ellipticity severely challenges precision cosmic shear measurement. We propose to self calibrate the induced gravitational shear-galaxy intrinsic ellipticity contamination (the GI correlation, Hirata & Seljak 2004) using extra information encoded in the same weak lensing survey. Besides the galaxy ellipticity-galaxy ellipticity correlation, the same ...

We consider the possible gain in the measurement of lensing shear from imaging data in multiple filters. Galaxy shapes may differ significantly across filters, so that the same galaxy offers multiple samples of the shear. On the other extreme, if galaxy shapes are identical in different filters, one can combine them to improve the signal-to-noise and thus increase the effective number density o...

MOTIVATION Galaxy is a software application supporting high-throughput biology analyses and work flows, available as a free on-line service or as source code for local deployment. New tools can be written to extend Galaxy, and these can be shared using public Galaxy Tool Shed (GTS) repositories, but converting even simple scripts into tools requires effort from a skilled developer. RESULTS Th...

We show that the 'Seyfert' galaxy SBS 1543+593 is a by-chance projection of the center of a nearby galaxy (z = 0.009) onto the bright QSO HS 1543+5921 (z = 0.807). The quasar has been discovered independently by the Hamburg Quasar Survey, an automated survey for bright QSOs based on digitized objective prism Schmidt plates. Direct imaging and subsequent spectroscopy of a faint (R = 22 m) HII re...

We use an all–sky, complete sample of nearby galaxies, extracted from the LEDA data base, to map the optical galaxy density field in the nearby universe. In order to determine this field, we correct the redshift–dependent distances by testing some peculiar velocity field models and we correct the galaxy number density for the incompletion of the galaxy sample at large distances through the deri...