Publications (16)
Dimensional reduction for sampled priors and application to photometric redshift distributions
Gary Bernstein, William Assignies Doumerg, Michael A. Troxel +35
A typical Bayesian inference on the values of some parameters of interest from some data involves running a Markov Chain (MC) to sample from the posterior $p({\bf q},{\…
DiffstarPop: A generative physical model of galaxy star formation history
Alex Alarcon, Andrew P. Hearin, Matthew R. Becker +3
We present DiffstarPop, a differentiable forward model of cosmological populations of galaxy star formation histories (SFH). In the model, individual galaxy SFH is parametrized by…
Diffstar: A Fully Parametric Physical Model for Galaxy Assembly History
Alex Alarcon, Andrew P. Hearin, Matthew R. Becker +1
We present Diffstar, a smooth parametric model for the in-situ star formation history (SFH) of galaxies. Diffstar is distinct from conventional SFH models that are used to interpre…
A Differentiable Model of the Assembly of Individual and Populations of Dark Matter Halos
Andrew P. Hearin, Jonás Chaves-Montero, Matthew R. Becker +1
We present a new empirical model for the mass assembly of dark matter halos. We approximate the growth of individual halos as a simple power-law function of time, where the power-l…
The PAU Survey: A Forward Modeling Approach for Narrow-band Imaging
Luca Tortorelli, Lorenza Della Bruna, Jörg Herbel +15
Weak gravitational lensing is a powerful probe of the dark sector, once measurement systematic errors can be controlled. In Refregier & Amara (2014), a calibration method based on…
The PAU Survey: narrowband photometric redshifts using Gaussian processes
John Y. H. Soo, Benjamin Joachimi, Martin Eriksen +16
We study the performance of the hybrid template-machine-learning photometric redshift (photo-) algorithm Delight, which uses Gaussian processes, on a subset of the early data re…
Propagating sample variance uncertainties in redshift calibration: simulations, theory and application to the COSMOS2015 data
Carles Sánchez, Marco Raveri, Alex Alarcon +1
Cosmological analyses of galaxy surveys rely on knowledge of the redshift distribution of their galaxy sample. This is usually derived from a spectroscopic and/or many-band photome…
DSPS: Differentiable Stellar Population Synthesis
Andrew P. Hearin, Jonás Chaves-Montero, Alex Alarcon +2
Models of stellar population synthesis (SPS) are the fundamental tool that relates the physical properties of a galaxy to its spectral energy distribution (SED). In this paper, we…
Machine learning synthetic spectra for probabilistic redshift estimation: SYTH-Z
Nesar Ramachandra, Jonás Chaves-Montero, Alex Alarcon +3
Photometric redshift estimation algorithms are often based on representative data from observational campaigns. Data-driven methods of this type are subject to a number of potentia…
The Physics of the Accelerating Universe Camera
Cristobal Padilla, Francisco J. Castander, Alex Alarcon +30
The PAU (Physics of the Accelerating Universe) Survey goal is to obtain photometric redshifts (photo-z) and Spectral Energy Distribution (SED) of astronomical objects with a resolu…
Dark Energy Survey Year 1 Results: Cosmological Constraints from Cluster Abundances and Weak Lensing
DES Collaboration, Tim Abbott, Michel Aguena +129
We perform a joint analysis of the counts and weak lensing signal of redMaPPer clusters selected from the Dark Energy Survey (DES) Year 1 dataset. Our analysis uses the same shear…
Cosmological constraints from multiple tracers in spectroscopic surveys
Alex Alarcon, Martin Eriksen, Enrique Gaztanaga
We use the Fisher matrix formalism to study the expansion and growth history of the Universe using galaxy clustering with 2D angular cross-correlation tomography in spectroscopic o…
The PAU Survey: An improved photo- sample in the COSMOS field
Alex Alarcon, Enrique Gaztanaga, Martin Eriksen +21
We present -- and make publicly available -- accurate and precise photometric redshifts in the ACS footprint from the COSMOS field for objects with . The re…
Redshift inference from the combination of galaxy colors and clustering in a hierarchical Bayesian model Application to realistic -body simulations
Alex Alarcon, Carles Sánchez, Gary M. Bernstein +1
Photometric galaxy surveys constitute a powerful cosmological probe but rely on the accurate characterization of their redshift distributions using only broadband imaging, and can…
Illuminating the Physics of Dark Energy with the Discovery Simulations
Gillian D. Beltz-Mohrmann, Adrian Pope, Alex Alarcon +10
In this paper, we present the Discovery simulations: a new pair of high-resolution N-body simulations motivated by the DESI Y1 BAO cosmological constraints on dark energy. The Disc…
Brightest Cluster Galaxy ellipticity as proxy for halo shape: Orientation bias, assembly bias, and potential selection effects in SZ-selected clusters
Radhakrishnan Srinivasan, Tae-hyeon Shin, Anja von der Linden +93
The orientation of triaxial galaxy clusters with respect to the line-of-sight is expected to be one of the prime sources of scatter and potential bias in optical observables (e.g.,…