Year: 2010
Type: article
Abstract: Cosmology with Type Ia supernova heretofore has required extensive spectroscopic follow-up to establish an accurate redshift. Though this resource-intensive approach is tolerable at the present discovery rate, the next generation of ground-based all-sky survey instruments will render it unsustainable. Photometry-based redshift determination may be a viable alternative, though the technique introduces non-negligible errors that ultimately degrade the ability to discriminate between competing cosmologies. We present a strictly template-based photometric redshift estimator and compute redshift reconstruction errors in the presence of statistical errors. Under highly degraded photometric conditions corresponding to a statistical error σ of 0.5, the residual redshift error is found to be 0.236 when assuming a nightly observing cadence and a single Large Synoptic Science Telescope (LSST) u -band filter. Utilizing all six LSST bandpass filters reduces the residual redshift error to 9.1 × 10 −3 . Assuming a more optimistic statistical error σ of 0.05, we derive residual redshift errors of 4.2 × 10 −4 , 5.2 × 10 −4 , 9.2 × 10 −4 , and 1.8 × 10 −3 for observations occuring nightly, every 5th, 20th and 45th night, respectively, in each of the six LSST bandpass filters. Adopting an observing cadence in which photometry is acquired with all six filters every 5th night and a realistic supernova distribution, binned redshift errors are combined with photometric errors with a σ of 0.17 and systematic errors with a σ∼ 0.003 to derive joint errors (σ w , ) of (0.012, 0.066), respectively, in ( w , w ') with 68% confidence using Fisher matrix formalism. Though highly idealized in the present context, the methodology is nonetheless quite relevant for the next generation of ground-based all-sky surveys.
Source: The Astrophysical Journal
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2020404208