iMaNGA: mock MaNGA galaxies based on IllustrisTNG and MaStar SSPs -- II. The catalogue

TL;DR

This paper presents the iMaNGA catalogue of simulated galaxies from TNG50, demonstrating its similarity to MaNGA observations in key properties and validating the spectral fitting methods for recovering galaxy characteristics.

Contribution

The paper introduces the iMaNGA catalogue based on TNG50 simulations, matching MaNGA selection, and validates spectral fitting for accurate recovery of galaxy properties.

Findings

iMaNGA sample closely matches MaNGA in stellar mass and size relations

Spectral fitting accurately recovers kinematics and stellar populations

Discrepancies in high-mass elliptical galaxy representation in TNG50

Abstract

Strengthening the synergy between simulations and observations is essential to test galaxy formation and evolution theories. To achieve this goal, in the first paper of this series, we presented a method to generate mock SDSS-IV/MaNGA integral-field spectroscopic galaxy observations from cosmological simulations. In this second paper, we build the iMaNGA catalogue consisting of $\sim$1,000 unique galaxies from the TNG50 cosmological simulations, selected to mimic the SDSS-IV/MaNGA-Primary sample selection. Here we present and discuss the iMaNGA sample and its comparison to the MaNGA Primary catalogue. The iMaNGA sample well recovers the MaNGA-Primary sample in terms of stellar mass vs angular size relation and spatial resolution. The S\'ersic index vs angular size relation, instead, is not reproduced well by the simulations, mostly because of a paucity of high-mass elliptical galaxies in TNG50. We also investigate our ability to recover the galaxy kinematics and stellar population properties with full-spectral fitting. We demonstrate that 'intrinsic' and `recovered' stellar kinematics, stellar ages and metallicities are consistent, with residuals compatible with zero within 1$-{\sigma}$. Also`intrinsic' and `recovered' star formation histories display a great resemblance. We conclude that our mock generation and spectral fitting processes do not distort the `intrinsic' galaxy properties. Therefore, in the third paper of this series, we can meaningfully test the cosmological simulations, comparing the stellar population properties and kinematics of the iMaNGA mock galaxies and the MaNGA observational results.