Supplementary data to "The Kinematically Hot, Extremely Metal-Poor C-19 Stellar Stream in DESI DR2"

Supplementary material to DESI's publication "The Kinematically Hot, Extremely Metal-Poor C-19 Stellar Stream in DESI DR2" to comply with the data management plan. Directory contains data behind all figures with file names indicating the figure that each file corresponds to. Directory also contains .fits files corresponding to Tables 5 (table5_full.fits) and 6 (table_6.fits) and the extended column versions of these tables (msrgb_members_allcols.fits, bhb_members_allcols.fits). The additional columns include Gaia DR3 astrometry/parallax, DECaLS photometry, further DESI columns, etc. In all, data for 10 figures and 2 tables included. Brief descriptions of contents for each file: bhb_members_allcols.fits Extended columns version of table_6.fits Columns: 'TARGET_RA', 'TARGET_DEC', 'FEH', 'FEH_ERR', 'TARGETID', 'VRAD', 'VRAD_ERR', 'PARALLAX_ERROR', 'PMDEC_ERROR', 'PMRA_ERROR', 'PMRA', 'PARALLAX', 'PMDEC', 'dist_mod', 'dist_mod_err', 'dist_kpc', 'FLUX_Z', 'FLUX_R', 'FLUX_G', 'EBV', 'VGSR', 'phi1', 'phi2', 'GAIA_SOURCE_ID' figure1.fits Sky positions (RA, DEC) of stars (this work, Yuan et al. 2025), identifies as members of C-19 as well as the RA, DEC orbit track fit to this work's C-19 members. figure2.fits Kinematic (galactocentric velocity, proper motions in RA and DEC) and [Fe/H] diamond data points for the STREAMFINDER (Ibata et al 2024) stars. figure3.fits Stream membership probabilities from the 2071 stars modelled. figure4.fits phi_1 (deg), phi_2 (deg), residual galactocentric velocity (km/s), residual proper motion in RA (mas/yr), residual proper motion in DEC (mas/yr), [Fe/H] (dex), and heliocentric distance (kpc), stream_prob (fraction) for the high probability stream members identified in this work. Residuals are with respect to modelled spline track. figure15.fits contains the non-residual values for those panels. The file containts 3 tables: 'STREAM_MEMBERS': MS+RGB member stars identified by the mixture model. 'BHB_MEMBERS': BHB member stars identified from the box cut approach. 'RV_MEMBERS_PREV': Yuan et al. 2025 members that were cross-matched in DESI. figure5.fits Colour (DECaLS g - r) and absolute magnitude (DECaLS r-band). Absolute magnitude assume a distance of 18 kpc and values are corrected using extinction coefficients from the DES DR1 (Abbot et al. 2018) E(B-V) values from Schlegel et al. (1998). The file contains 5 tables: 'C19_MEMBERS': MS+RGB member stars identified for this work 'BHB_MEMBERS': BHB members identified in this work 'YUAN_POINTS' Yuan et al. 2025 members cross-matched in DESI (1:1 overlap with MS+RGB members from this work) 'MSRGB_TRACK': Dotter (2016) isochrone for MS+RGB population with [Fe/H]=-2.49 and at an age of 13.5 Gyr. 'HB_TRACK': Emperical horizontal branch of M92 from the Harris et al. (1996) catalogue placed at 18 kpc. figure6.fits phi_1 (deg), phi_2 (deg), galactocentric velocity (km/s), proper motion RA (mas/yr), proper motion DEC (mas/yr), [Fe/H] (dex) for stars surviving the box cuts about the modelled spline tracks. The files contains 2 tables: 'MSRGB': MS+RGB stars surviving all box cuts 'BHB': BHB stars surviving all box cuts. figure7.fits phi_1 (deg), phi_2 (deg), galactocentric velocity (km/s), and delta galactocentric velocity (km/s) for very high probability members (>0.9) and tracks/splines. The file containts 3 tables: 'MEMBERS': very high probability member stars. 'TRACKS': 1000 samples along phi_1 for galactocentric velocity spline, 5-spline velocity dispersion spline, and stream fraction spline. 'SIGMA_BINS': velocity dispersion mean and spread for three bins along phi_1. figure8.fits proper motion in RA (mas/yr) and proper motion in DEC (mas/yr) for high probability member stars and orbit track. The file contains 2 tables: 'STREAM_POINTS': high probability member stars. 'ORBIT_TRACK': 2002 points along orbit track form this work in pmra/pmdec space. figure9.fits phi_1 (deg), phi_2 (deg) for Gaia+DECaLS stars remaining after cuts informed by mixture model results. Boolean column included for wether stars fall within +-2 degrees in phi_2 about orbit track. This fuel contains 1 table: 'GAIA_DECALS' figure10.fits phi_1 (deg), phi_2 (deg), and completeness values across the C-19 footprint. The file contains 1 tables: 'COMPLETENESS_MAP': DESI spectroscopic completeness fraction relative to Gaia+DECaLS sampled on a phi_1, phi_2 grid (462 points). msrgb_members_allcols.fits Extended columns version of table5_full.fits Columns: 'TARGET_RA', 'TARGET_DEC', 'FEH', 'FEH_ERR', 'TARGETID', 'VRAD', 'VRAD_ERR', 'PARALLAX_ERROR', 'PMDEC_ERROR', 'PMRA_ERROR', 'PMRA', 'PARALLAX', 'PMDEC', 'dist_mod', 'dist_mod_err', 'dist_kpc', 'FLUX_Z', 'FLUX_R', 'FLUX_G', 'EBV', 'VGSR', 'phi1', 'phi2', 'stream_prob', 'stream_prob_em', 'stream_prob_ep', 'r_mag', 'GAIA_SOURCE_ID' table_6.fits 6 BHB stars identified as members by box cut approach. 'SOURCE_ID', 'TARGET_RA', 'TARGET_DEC', 'dist_kpc', 'VRAD', 'VGSR', 'VGSR_ERR', 'FEH', 'FEH_ERR' table5_full.fits Full 61 row version of table 5, listing DESI stars with member probabilities > 0.01. 'TARGET_RA', 'TARGET_DEC', 'FEH', 'FEH_ERR', 'VRAD', 'VGSR', 'VRAD_ERR', 'stream_prob', 'GAIA_SOURCE_ID'