The Fall 2004 SDSS Supernova Survey

TL;DR

The paper reports on the early results of the 2004 SDSS Supernova Survey, which detected and spectroscopically confirmed 22 supernovae, including 16 type Ia, to improve understanding of supernovae for cosmology.

Contribution

This study presents the first results from the SDSS II supernova survey, including the detection and confirmation of supernovae in the redshift desert, aiding future cosmological research.

Findings

22 spectroscopically confirmed supernovae, including 16 type Ia

Coverage of the redshift interval z=0.05-0.35 for supernovae

Identification of unusual supernovae for further study

Abstract

In preparation for the Supernova Survey of the Sloan Digital Sky Survey (SDSS) II, a proposed 3-year extension to the SDSS, we have conducted an early engineering and science run during the fall of 2004, which consisted of approximately 20 scheduled nights of repeated imaging of half of the southern equatorial stripe. Transient supernova-like events were detected in near real-time and photometric measurements were made in the five SDSS filter bandpasses with a cadence of ~2 days. Candidate type Ia supernovae (SNe) were pre-selected based on their colors, light curve shape, and the properties of the host galaxy. Follow-up spectroscopic observations were performed with the Astrophysical Research Consortium 3.5m telescope and the 9.2m Hobby-Eberly Telescope to confirm their types and measure the redshifts. The 2004 campaign resulted in 22 spectroscopically confirmed SNe, which includes 16 type Ia, 5 type II, and 1 type Ib/c. These SN Ia will help fill in the sparsely sampled redshift interval of z = 0.05 - 0.35, the so-called 'redshift desert', in the Hubble diagram. Detailed investigation of the spectral properties of these moderate-redshift SNe Ia will also provide a bridge between local SNe and high-redshift objects, and will help us understand the systematics for future cosmological applications that require high photometric precision. Finally, the large survey volume also provides the opportunity to select unusual supernovae for spectroscopic study that are poorly sampled in other surveys. We report on some of the early results from this program and discuss potential future applications.