Stephen Kuhlmann

SNANA: A Public Software Package for Supernova Analysis

We describe a general analysis package for supernova (SN) light curves, called SNANA, that contains a simulation, a light-curve fitter, and a cosmology fitter. The software is designed with the primary goal of using SNe Ia as distance indicators for the determination of cosmological parameters, but it can also be used to study efficiencies for analyses of SN rates, estimate contamination from non-Ia SNe, and optimize future surveys. Several SN models are available within the same software architecture, allowing technical features such as K-corrections to be consistently used among multiple models, and thus making it easier to make detailed comparisons between models. New and improved light-curve models can be easily added. The software works with arbitrary surveys and telescopes and has already been used by several collaborations, leading to more robust and easy-to-use code. This software is not intended as a final product release, but rather it is designed to undergo continual improvements from the community as more is learned about SNe. We give an overview of the SNANA capabilities, as well as some of its limitations.

Results from the Supernova Photometric Classification Challenge

We report results from the Supernova Photometric Classification Challenge (SNPhotCC), a publicly released mix of simulated supernovae (SNe), with types (Ia, Ibc, and II) selected in proportion to their expected rates. The simulation was realized in the griz filters of the Dark Energy Survey (DES) with realistic observing conditions (sky noise, point-spread function, and atmospheric transparency) based on years of recorded conditions at the DES site. Simulations of non-Ia-type SNe are based on spectroscopically confirmed light curves that include unpublished non-Ia samples donated from the Carnegie Supernova Project (CSP), the Supernova Legacy Survey (SNLS), and the Sloan Digital Sky Survey-II (SDSS-II). A spectroscopically confirmed subset was provided for training. We challenged scientists to run their classification algorithms and report a type and photo-z for each SN. Participants from 10 groups contributed 13 entries for the sample that included a host-galaxy photo-z for each SN and nine entries for the sample that had no redshift information. Several different classification strategies resulted in similar performance, and for all entries the performance was significantly better for the training subset than for the unconfirmed sample. For the spectroscopically unconfirmed subset, the entry with the highest average figure of merit for classifying SNe Ia has an efficiency of 0.96 and an SN Ia purity of 0.79. As a public resource for the future development of photometric SN classification and photo-z estimators, we have released updated simulations with improvements based on our experience from the SNPhotCC, added samples corresponding to the Large Synoptic Survey Telescope (LSST) and the SDSS-II, and provided the answer keys so that developers can evaluate their own analysis.

Graphical User Interfaces of the Dark Energy Survey

The Dark Energy Survey (DES) is a 5000 square degree survey of the southern galactic cap set to take place on the Blanco 4-m telescope at Cerra Tololo Inter-American Observatory. A new 500 MP camera and control system are being developed for this survey. To facilitate the data acquisition and control, a new user interface is being designed that utilizes the massive improvements in web based technologies in the past year. The work being done on DES shows that these new technologies provide the functionality and performance required to provide a productive and enjoyable user experience in the browser.

Photonic ring resonator notch filters for astronomical OH suppression

Photonic ring resonators used as wavelength notch filters are a promising novel solution to enable astronomical instruments to remove the signal from atmospheric OH emission in the near-infrared wavelength range. We derive design requirements from theory and finite difference time domain simulations. We find rings with radii less than 10 microns provide an adequate free spectral range for silicon nitride abd less than 3 microns for silicon. One challenge for this application is the requirement for many rings in series to suppress particular wavelengths within 0.2nm. We report progress in fabricating both silicon and silicon nitride rings for OH suppression.