geko : A tool for modelling galaxy kinematics and morphology in JWST /NIRCam slitless spectroscopic observations

Clicks: 15
ID: 332542
2026
Free PDF
Article Quality & Performance Metrics
Overall Quality
Not rated
Combines reader engagement with the AI quality analysis. This article has not been analysed, so there is no overall score — reader engagement is measured and shown alongside.
AI Quality Assessment
Not analyzed
Readership in this journal
Emerging

Ranked #946 of 1,339 articles by views in monthly notices of the royal astronomical society

Most read Least read

Bar heights use a square-root scale. Only the 120 most-read articles are drawn; the journal has 1,339 in total.

Mint this article as an NFT
Not yet minted

Create a permanent, verifiable on-chain record of this article on the Scimatic Network. The NFT is held in your Journament account, and you can withdraw it to your own wallet at any time.

5 SUSD one-off · no wallet required
Sign in to mint
Abstract
Abstract Wide-field slitless spectroscopy (WFSS) is a powerful tool for studying large samples of galaxies across cosmic time. With the arrival of JWST, and its NIRCAM grism mode, slitless spectroscopy can reach a medium spectral resolution of (R ∼ 1600), allowing it to spatially resolve the ionised-gas kinematics out to z ∼ 9. However, the kinematic information is convolved with morphology along the dispersion axis, a degeneracy that must be modelled to recover intrinsic properties. We present the Grism Emission-line Kinematics tOol (geko), a Python package that forward-models NIRCam grism observations and infers emission-line morphologies and kinematics within a Bayesian framework. geko combines Sérsic surface-brightness models with arctangent rotation curves, includes full point-spread function (PSF) convolution and forward-modelling of the grism dispersion, and leverages gradient-based sampling via jax/numpyro for efficient inference. It recovers parameters such as effective radius, velocity dispersion, rotational velocity, rotational support, and dynamical mass, with typical run times of ∼20 minutes per galaxy on GPUs. We validate performance using extensive mock data spanning position angle, S/N, and morphology, quantifying where degeneracies limit recovery. Finally, we demonstrate applications to real FRESCO Hα emitters at z ≈ 4 − 6, recovering both rotation- and dispersion-dominated systems. geko opens the way to statistical studies of galaxy dynamics in the early Universe and is publicly available at https://github.com/angelicalola-danhaive/geko.
Reference Key
openalex_W7222529164 Use this key to autocite in the manuscript while using SciMatic Manuscript Manager or Thesis Manager
Authors A. Lola Danhaive, Sandro Tacchella
Are you one of these authors? Claim your profile
Journal monthly notices of the royal astronomical society
Year 2026
DOI
10.1093/mnras/stag1965
URL
https://doi.org/10.1093/mnras/stag1965
Keywords Keywords not found

Citations

No citations found. To add a citation, contact the admin at info@scimatic.org

Comments

No comments yet. Be the first to comment on this article.