Day 1030

Wednesday.  Thursday.  Christmas.  Monday.  Tuesday.


1512.07914
The LSST data management system
Juric, et al

LSST is a large-aperture, wide-field, ground-based sure system that will image the sky in 6 optical bands from 320 to 1050 nm, uniformly covering approximately 18k deg.sq. of the sky over 800 times.  The LSST is currently under construction on Cerro Pachon in Chile, and expected to enter operations in 2022.  Once operational, the LSST will explore a wide range of astrophysical questions, from discovering "killer" asteroids to examining the nature of DE.  The LSST will generate on average 15 TB of data per night, and will require a comprehensive Data Management system to reduce the raw data to scientifically useful catalogs and images with minimum human intervention.  These reductions will result in a real-time alert stream, and 11 data releases over the 10-year duration of LSST operations.  To enable this processing, the LSST project is developing a new, general-purpose, high-performance, scalable, well documented, open source data processing software stack for O/IR surveys.  Prototypes of this stack are already capable of processing data from existing cameras (e.g., SDSS, DECam, MegaCam), and form the basis of the HSC survey data reduction pipeline.


1512.07916
A free-form mass model of the Hubble Frontier Fields Cluster AS1063 (RXC J2248.l7-4431) with over one hundred constraints
Diego, Broadhurst, Wong, Silk, Lim, Zheng, Lam

Derive a free-form mass distribution for the massive cluster AS1063 (z=0.348) using the completed optical imaging from the HFF program.  Based on a subset of 11 multiply lensed systems with spectroscopic redshift, produce a lens model that is accurate enough to unveil new multiply lensed systems, totally over a 100 arclets  and to estimate their redshifts geometrically.  Consistency is found between this precise model and that obtained using one the subset of lensed sources with spectroscopically measured redshifts.  No significant offset is found between the centroid of the mass distribution and that of the X-ray emission map, suggesting a relatively relaxed state for this cluster, although a relatively large elongation of the mass distribution is apparent relative to the X-ray map.  For the well resolved lensed images, provide detailed model comparisons to illustrate the precision of the model and hence the reliability of the de-lensed sources.  A clear linear structure is associated with one such source extending 23 kpc in length, that could be an example f jet-induced star formation, at z=3.1.