EPS Research Intermediate-z Kinematic Corpus v1.0 (IntZ_v1): KROSS + KMOS³D Galaxy Kinematics at z~0.4–2.7

 

Part of the EPS Research multi‑epoch kinematic platform: Full datasets, cross‑epoch corpora, executable examples, and the Astro‑Extractor are available at https://github.com/eps-research/rag-corpus-series 

Machine-readable kinematic corpus of 1,292 star-forming galaxies at
z = 0.382–2.675 (median z = 0.922), combining the KROSS survey
(Harrison et al. 2017; Johnson et al. 2018) and the KMOS³D survey
(Wisnioski et al. 2019). Part of the EPS Research RAG Corpus Series
(platform DOI: 10.5281/zenodo.20398430).

CORPUS STRUCTURE:
- Total galaxies: 1,292
- KROSS (Harrison et al. 2017): 586 galaxies, z~0.6–1.0
- KMOS³D (Wisnioski et al. 2019): 706 galaxies, z~0.4–2.7
- Tier-1 (spatially resolved kinematics): 166 galaxies (all KROSS)
- Tier-2 (integrated kinematics only): 1,126 galaxies

OMEGA CORRECTION (Flynn & Cannaliato 2025):
The kinematic omega correction V_adj = V_obs − Rω is computed for all
166 Tier-1 galaxies following Flynn & Cannaliato (2025, arXiv:2604.13489).
Omega values represent the angular velocity correction term derived from
the two-boundary rotation curve prescription. Key statistics:
- N with omega: 166/166 Tier-1 galaxies
- Omega median: −9.087 rad/Gyr (stdev 8.940 rad/Gyr)
- Omega range: −63.7 to −1.7 rad/Gyr
- Omega outliers (>3-sigma): 4 galaxies flagged

EMPIRICAL COMPARISON WITH OTHER EPOCHS:
For reference, omega medians from other corpora in this series are:
- z=0  SPARC (84 galaxies):  median ω = +7.06 rad/Gyr
- z~0.9 IntZ (166 galaxies): median ω = −9.087 rad/Gyr  [this corpus]
- z~5  ALPINE (8 galaxies):  median ω = −13.05 rad/Gyr

Note: These three samples use different kinematic tracers (HI 21cm,
Hα, and [CII] respectively) and probe different physical radii. The
sign difference across epochs is an empirical finding in the computed
omega values. Physical interpretation, including tracer corrections and
robustness tests, is deferred to Flynn & Cannaliato (in preparation).
The z~5 ALPINE result is preliminary (N=8) and is presented as an
illustrative high-z comparison only.

THREE CANONICAL EXAMPLES:
1. KID-141 (C-zcos_z1_633): KROSS Tier-1, z=0.9822, Vc=256.97 km/s,
   log M*=10.48, SFR=8.29 Msun/yr, R_half=3.05 kpc, ω=−16.507 rad/Gyr.
   Massive main-sequence rotator at z~1.

2. GS4_33971: KMOS³D Tier-2, z=2.6754, log M*=10.83, SFR=187.6 Msun/yr,
   sigma=53.6 km/s, omega=not available (integrated kinematics only).
   Massive starburst at cosmic noon; representative of Tier-2 sample.

3. KID-522 (S-zvipe_z1_827): KROSS Tier-1, z=0.8237, Vc=186.09 km/s,
   sigma0=17.95 km/s, v/sigma=10.37, R_half=1.08 kpc, ω=−33.827 rad/Gyr.
   Compact, highly rotation-dominated disk. Note: this galaxy has among
   the largest |ω| values in the corpus and has been manually verified;
   sigma0 is near the KROSS instrumental floor and should be treated
   with caution.

EXCLUDED SURVEY:
MOSDEF (Price et al. 2020, ApJ 894, 91) was evaluated for inclusion.
The individual galaxy kinematic catalog for this survey is not publicly
archived; only binned median statistics are published. Data request
recommended to S. Price. This exclusion is documented in the corpus
metadata block.

DATA QUALITY (v1b fixes applied 2026-05-29):
- beam_smear_corrected set to False for all 706 KMOS³D integrated
  line widths (field represents integrated line width, not σ₀)
- 684 sentinel values (−999.0) replaced with null
- 5 sigma values >250 km/s flagged; 2 values >1000 km/s flagged
  with RAG summary caution (probable AGN or bad fits)
- 4 omega outliers (>3-sigma threshold 35.9 rad/Gyr) flagged
- Wisnioski citation corrected to 2019 ApJ 886 124
- MOSDEF exclusion documented in corpus_metadata block
- All 3 canonical examples verified pass structural QC

FILES:
- intz_corpus_v1b.json       Full corpus, nested schema (4.1 MB)
- intz_corpus_v1b.jsonl      One galaxy per line, RAG-ready (3.2 MB)
- intz_corpus_v1b_flat.csv   Flattened table, 1292 rows (279 KB)
- intz_corpus_v1b_overview.png  Six-panel summary figure

COSMOLOGY: Planck ΛCDM 2018 (Planck Collaboration 2020, A&A 641 A6):
H0=70 km/s/Mpc, Ω_m=0.3, Ω_Λ=0.7

REFERENCES:
- Harrison et al. 2017, MNRAS 467, 1965 (KROSS survey)
- Johnson et al. 2018, MNRAS 474, 5076 (KROSS data release)
- Wisnioski et al. 2019, ApJ 886, 124 (KMOS³D final data release)
- Lelli et al. 2016, AJ 152, 157 (SPARC, z=0 comparison corpus)
- Le Fèvre et al. 2020, A&A 643, A1 (ALPINE, z~5 comparison)
- Price et al. 2020, ApJ 894, 91 (MOSDEF, excluded — see above)
- Flynn & Cannaliato 2025, arXiv:2604.13489 (omega correction method)
- Planck Collaboration 2020, A&A 641, A6 (cosmological parameters)

Full Platform: This dataset is part of the EPS Research multi‑epoch kinematic platform (SPARC + THINGS + LITTLE THINGS + WALLABY DR2 + Milky Way GC corpus + z≥6). All corpora, executable notebooks, the Astro‑Extractor, and the unified schema are available at: https://github.com/eps-research/rag-corpus-series