A catalogue of 2D photometric decompositions in the SDSS-DR7 spectroscopic main galaxy sample: preferred models and systematics

TL;DR

This paper presents a comprehensive catalogue of 2D photometric decompositions for over 700,000 SDSS galaxies, analyzing model preferences, systematics, and biases to aid future galaxy research.

Contribution

It provides the first large-scale, PSF-corrected 2D galaxy decomposition catalogue with systematic analysis and an accessible interface for visualizing models and residuals.

Findings

Over 90% of two-component fits are reliable for analysis.

Fits follow expected patterns for different galaxy types.

Biases such as bars and resolution affect bulge measurements.

Abstract

We present a catalogue of two-dimensional, point spread function-corrected de Vacouleurs, S\'{e}rsic, de Vacouleurs+Exponential, and S\'{e}rsic+Exponential fits of $\sim7\times10^5$ spectroscopically selected galaxies drawn from the Sloan Digital Sky Survey (SDSS) Data Release 7. Fits are performed for the SDSS r band utilizing the fitting routine GALFIT and analysis pipeline PYMORPH. We compare these fits to prior catalogues. Fits are analysed using a physically motivated flagging system. The flags suggest that more than 90 per cent of two-component fits can be used for analysis. We show that the fits follow the expected behaviour for early and late galaxy types. The catalogues provide a robust set of structural and photometric parameters for future galaxy studies. We show that some biases remain in the measurements, e.g. the presence of bars significantly affect the bulge measurements although the bulge ellipticity may be used to separate barred and non-barred galaxies, and about 15 percent of bulges of two-component fits are also affected by resolution. The catalogues are available in electronic format. We also provide an interface for generating postage stamp images of the 2D model and residual as well as the 1D profile. These images can be generated for a user-uploaded list of galaxies on demand.