@article {498691,
	title = {Exploring photometric redshifts as an optimization problem: an ensemble MCMC and simulated annealing-driven template-fitting approach},
	journal = {Monthly Notices of the Royal Astronomical Society},
	volume = {461},
	year = {2016},
	month = {October 1, 2016},
	pages = {3432-3442},
	abstract = {Using a 4D grid of \~{}2 million model parameters (Δz = 0.005)adapted from Cosmological Origins Survey photometric redshift (photo-z)searches, we investigate the general properties of template-basedphoto-z likelihood surfaces. We find these surfaces are filled withnumerous local minima and large degeneracies that generally confoundsimplistic gradient-descent optimization schemes. We combine ensembleMarkov Chain Monte Carlo sampling with simulated annealing to robustlyand efficiently explore these surfaces in approximately constant time.Using a mock catalogue of 384 662 objects, we show our approach samples\~{}40 times more efficiently compared to a {\textquoteleft}brute-force{\textquoteright} counterpartwhile maintaining similar levels of accuracy. Our results representfirst steps towards designing template-fitting photo-z approacheslimited mainly by memory constraints rather than computation time.},
	keywords = {methods: statistical;  techniques: photometric;  galaxies: distances and redshifts},
	isbn = {0035-8711},
	url = {http://adsabs.harvard.edu/abs/2016MNRAS.461.3432S},
	author = {Speagle, Joshua S. and Capak, Peter L. and Daniel J. Eisenstein and Masters, Daniel C. and Steinhardt, Charles L.}
}
