Simulating gas kinematic studies of high-redshift galaxies with the HARMONI Integral Field Spectrograph

TL;DR

This paper simulates high-redshift galaxy observations with the HARMONI spectrograph, assessing how instrumental effects influence the recovery of galaxy kinematics from mock data.

Contribution

It introduces a new pipeline combining cosmological simulations with detailed instrument simulation to study observational biases in galaxy kinematic measurements.

Findings

Biases in kinematic measurements depend on the point spread function.

Simulated observations can accurately recover galaxy properties with proper modeling.

Instrumental effects significantly influence the interpretation of high-redshift galaxy data.

Abstract

We present simulated observations of gas kinematics in galaxies formed in 10 pc resolution cosmological simulations with the hydrodynamical + N-body code RAMSES, using the new RAMSES2HSIM pipeline with the simulated observing pipeline (HSIM) for the ELT HARMONI IFU spectrograph. We post-process the galaxy's gas kinematics and H{\alpha} line emission for each simulation cell, and integrate the emission to produce an extinction-corrected input cube. We then simulate observations of the input cube with HARMONI, for a range of exposure times, spatial sampling, and spectral resolution. We analyze the mock observations to recover galaxy properties such as its kinematics and compare with the known simulation values. We investigate the cause of biases between the 'real' and 'observed' kinematic values, demonstrating the sensitivity of the inferred rotation curve to knowledge of the instrument's point spread function.