Lessons learned from studying H α galaxy kinematics with mock JWST/NIRSpec IFU observations at z > 6

Phillips, S; Rizzo, F; Kohandel, M; Smit, R; Pallottini, A

Lessons learned from studying H α galaxy kinematics with mock JWST/NIRSpec IFU observations at z > 6

Export Citation

Phillips, S ORCID: 0000-0003-4652-1090, Rizzo, F ORCID: 0000-0001-9705-2461, Kohandel, M ORCID: 0000-0003-1041-7865, Smit, R ORCID: 0000-0001-8034-7802 and Pallottini, A ORCID: 0000-0002-7129-5761 (2025) Lessons learned from studying H α galaxy kinematics with mock JWST/NIRSpec IFU observations at z > 6. Monthly Notices of the Royal Astronomical Society, 544 (3). pp. 2758-2776. ISSN 0035-8711

[thumbnail of Lessons learned from studying H α galaxy kinematics with mock JWSTNIRSpec IFU observations at z 6.pdf]

Preview

Text
Lessons learned from studying H α galaxy kinematics with mock JWSTNIRSpec IFU observations at z 6.pdf - Published Version
Available under License Creative Commons Attribution.
Download (8MB) | Preview

Publisher URL: https://doi.org/10.1093/mnras/staf1681

Abstract

Galaxies with a disc morphology have been established at z > 9 with the James Webb Space Telescope (JWST). However, confirming their disc-like nature requires studying their gas kinematics, which can be challenging when relying solely on the warm gas observed by JWST. Unlike the cold gas traced by the Atacama Large Millimetre/Submillimetre Array (ALMA), warm gas is sensitive to outflows, complicating the interpretation of the disc dynamics. This elicits the question of how to compare information obtained from varied tracers, as well as how to physically interpret the low angular and spectral resolution observations generally available at high redshift. We address these challenges through comparative kinematic analysis of idealized and realistic JWST Near-Infrared Spectrograph integral field unit (NIRSpec/IFU) mock observations derived from two galaxies in the serra suite of cosmological zoom-in simulations. With these synthetic data, we determine the robustness of dynamical information recovered from typical IFU observations, and test widely used criteria for identifying discs and gaseous outflows at high redshift. We find that at the typical NIRSpec/IFU spectral and angular resolution (0.05 arcsec pixel-1), non-circular motions due to inflows or outflows can mimic the smooth velocity gradient indicative of a disc, and bias measured velocity dispersion upwards by a factor of 2-3×. As a result, the level of rotational support may be underestimated in the NIRSpec/IFU observations. However, the recovered dynamical mass appears to be relatively robust despite biases in and.

Item Type:	Article
Uncontrolled Keywords:	galaxies: high redshift; galaxies: kinematics and dynamics; astro-ph.GA; astro-ph.GA; 5101 Astronomical Sciences; 51 Physical Sciences; 5101 Astronomical Sciences; 51 Physical Sciences; 0201 Astronomical and Space Sciences; Astronomy & Astrophysics; 5101 Astronomical sciences; 5107 Particle and high energy physics; 5109 Space sciences
Subjects:	Q Science > QB Astronomy
Divisions:	Astrophysics Research Institute
Publisher:	Oxford University Press
Date of acceptance:	27 September 2025
Date of first compliant Open Access:	5 June 2026
Date Deposited:	05 Jun 2026 14:18
Last Modified:	05 Jun 2026 14:18
DOI or ID number:	10.1093/mnras/staf1681
URI:	https://researchonline.ljmu.ac.uk/id/eprint/28753

View Item

CORE (COnnecting REpositories)