Approximations to galaxy star formation rate histories: properties and uses of two examples

Abstract

Galaxies evolve via a complex interaction of numerous different physical processes, scales and components. In spite of this, overall trends often appear. Simplified models for galaxy histories can be used to search for and capture such emergent trends, and thus to interpret and compare results of galaxy formation models to each other and to nature. Here, two approximations are applied to galaxy integrated star formation rate histories, drawn from a semi-analytic model grafted onto a dark matter simulation. Both a lognormal functional form and principal component analysis (PCA) approximate the integrated star formation rate histories fairly well. Machine learning, based upon simplified galaxy halo histories, is somewhat successful at recovering both fits. The fits to the histories give fixed time star formation rates which have notable scatter from their true fixed time rates at final time, especially for quiescent and "green valley" galaxies, and more so for the PCA fit. For classifying galaxies into subfamilies sharing similar integrated histories, both approximations are better than using final stellar mass or specific star formation rate. Several subsamples from the simulation illustrate how these simple parameterizations can provide points of contact for comparisons between different galaxy formation samples, or more generally, models. As a side result, the halo masses of simulated galaxies with early peak star formation rate (according to the lognormal fit) lie on one of two tracks. The small fraction of galaxies with a lower halo mass at peak star formation rate appear to stall in their halo growth, even though they are central in their host halos.

Final version, to appear in the MNRAS. Helpful suggestions and tests from referee now included. Reference to PCA work on star formation rate histories now correctly attributed to Sparre et al (2015)

References in corpus (10)

• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• The star formation main sequence and stellar mass assembly of galaxies in the Illustris simulation
• The evolution of star formation histories of quiescent galaxies
• The impact of galactic properties and environment on the quenching of central and satellite galaxies: A comparison between SDSS, Illustris and L-Galaxies
• Painting galaxies into dark matter halos using machine learning
• Cosmological constraints from the CFHTLenS shear measurements using a new, accurate and flexible way of predicting nonlinear mass clustering
• Modeling the Impact of Baryons on Subhalo Populations with Machine Learning
• The New Galaxy Evolution Paradigm Revealed by the Herschel Surveys
• Characterizing simulated galaxy stellar mass histories
• The resolved star formation history of M51a through successive Bayesian marginalization

Cited by in corpus (8)

• How to measure galaxy star-formation histories I: Parametric models
• Learning the Relationship between Galaxies Spectra and their Star Formation Histories using Convolutional Neural Networks and Cosmological Simulations
• Relating the structure of dark matter halos to their assembly and environment
• MAHGIC: A Model Adapter for the Halo-Galaxy Inter-Connection
• A machine learning approach for identifying the counterparts of submillimetre galaxies and applications to the GOODS-North field
• Mysteries of Capotauro: investigating the puzzling nature of an extreme F356W-dropout
• Applying unsupervised learning to resolve evolutionary histories and explore the galaxy-halo connection in IllustrisTNG
• Ultra High-Redshift or Closer-by, Dust-Obscured Galaxies? Deciphering the Nature of Faint, Previously Missed F200W-Dropouts in CEERS