(LRDs)² II — DESI DR1 Low-Redshift Little Red Dots: catalog & spectra

(LRDs)² II — DESI DR1 Low-Redshift Little Red Dots: catalog & spectra Data release accompanying: (LRDs)²: The Low-ReDshift Little Red Dots Survey. II. DESI DR1 Sample Xiaojing Lin, Xiaohui Fan, Zheng Cai, Yichen Liu, Fengwu Sun, et al. The Astrophysical Journal (submitted, 2026). arXiv:2605.21574 If you use these data, please cite the paper above and this Zenodo record (DOI: 10.5281/zenodo.20309303). This release provides a machine-readable catalog (every measurement from the paper's five tables), three auxiliary tables, and the combined DESI spectra for all 27 low-redshift Little Red Dots (LRDs) in the sample. Contents README.md this filetables master_table.ecsv full catalog: 27 LRDs × 112 columns line_ratios_table.ecsv BPT / He II ratios + Balmer dec. + O32 + Mg II EW: 27 LRDs × 34 columns lines_table.ecsv auxiliary weak-line fits: 27 LRDs × 101 columns sdss_local_lrds.ecsv 3 local SDSS comparison LRDs (Lin+26, https://arxiv.org/pdf/2507.10659): 3 × 46 columnsDESI-DR1-spec.zip 27 combined DESI spectra (one per object); unzips to DESI-DR1-spec/DESI_<shortname>.fits The 27 objects are split into a Gold tier (19 sources with red optical slope k_red > 0 at ≥3σ) and a Silver tier (8 sources with k_red > 0 at <3σ); see the tier column. Catalog (master_table.ecsv) It bundles every measurement from the manuscript's five tables. Every measured quantity Q is followed by Q_err_low and Q_err_high, the asymmetric 1σ (16th/84th-percentile) uncertainties from the posterior; for symmetric (± in the paper) errors the two are equal. An empty cell means not measured / no spectral coverage (read back as NaN): the 9 objects without Balmer absorption have blank absorption columns, and the 10 without near-IR continuum coverage have blank modified-blackbody columns. All luminosities are observed (not extinction-corrected); velocities are negative for blueshift. Identity & metadata (9 columns) Column Description shortname Short ID, e.g. J1717+3807 (also the spectrum filename key) iau_name Full IAU name, e.g. J171741.74+380752.47 targetid DESI TARGETID ra_deg,dec_deg ICRS coordinates (deg) z Spectroscopic redshift tier Gold or Silver (see above) desi_reduction DESI reduction the spectrum is from (iron (DR1) for all 27) spectrum_file Path to this object's spectrum, DESI-DR1-spec/DESI_<shortname>.fits (see Spectra) Continuum (manuscript Table 1; 27 objects) Broken-power-law fit f_λ ∝ (λ/λ_v)^k to the rest-UV–optical continuum. Column Unit Description M_UV mag Absolute magnitude at rest-frame 1500 Å L5100 10⁴³ erg s⁻¹ Continuum luminosity at rest-frame 5100 Å lambda_v Å (rest) Inflection ("V" vertex) wavelength of the broken power law k_blue — Power-law slope blueward of lambda_v (locally fit, ≠ global β_UV) k_red — Power-law slope redward of lambda_v balmer_break — Balmer-break strength = F(4000–4100 Å) / F(3620–3720 Å), rest-frame absorber — Balmer line(s) with detected absorption: Ha, Hb, Ha+Hb, or blank Emission lines (manuscript Table 3; 27 objects) Narrow components share one FWHM; broad Hβ/Hα are 2–3 components — the *_broad columns give the composite (i.e., the summed profile of all broad components and the corresponding overall luminosity and FWHM). Column Unit Description FWHM_narrow km s⁻¹ Shared narrow-component FWHM L_OIII_narrow 10⁴⁰ erg s⁻¹ [O III] λ5008 narrow luminosity L_Hb_narrow 10⁴⁰ erg s⁻¹ Hβ narrow luminosity FWHM_Hb_broad km s⁻¹ Hβ composite broad FWHM L_Hb_broad 10⁴⁰ erg s⁻¹ Hβ composite broad luminosity L_Ha_narrow 10⁴⁰ erg s⁻¹ Hα narrow luminosity FWHM_Ha_broad km s⁻¹ Hα composite broad FWHM L_Ha_broad 10⁴⁰ erg s⁻¹ Hα composite broad luminosity Balmer absorption (manuscript Table 2; 18 objects) Voigt-profile absorber fits; Hβ and Hα modeled independently. Columns are repeated with _Hb / _Ha suffixes. Blank for the 9 objects with no absorber. Column Unit Description v_{Hb,Ha}_abs km s⁻¹ Absorber velocity shift vs. emission-line center (− = blueshift) logN_{Hb,Ha} log cm⁻² Absorbing-gas column density b_{Hb,Ha} km s⁻¹ Doppler parameter Cf_{Hb,Ha} — Covering factor (fixed to 1 when the posterior peaks there) EW_{Hb,Ha} Å Rest-frame absorption equivalent width Ionized outflows (manuscript Table 4; 27 objects) Column Unit Description dv_out km s⁻¹ Outflow velocity offset L_OIII_out 10⁴⁰ erg s⁻¹ [O III] outflow luminosity FWHM_out km s⁻¹ Outflow FWHM L_Hb_out 10⁴⁰ erg s⁻¹ Hβ outflow luminosity L_Ha_out 10⁴⁰ erg s⁻¹ Hα outflow luminosity Modified blackbody (manuscript Table 5; 17 objects) MBB fit to the blackbody-like optical–NIR continuum. T_MB and beta_MB are phenomenological (no physical interpretation; see paper). Blank for the 10 objects without sufficient near-IR coverage. Column Unit Description lambda_peak Å (rest) Peak wavelength of the MBB T_peak K Temperature from Wien's law applied to lambda_peak logL_bb log erg s⁻¹ Bolometric luminosity of the MBB T_MB K MBB characteristic temperature (phenomenological) beta_MB — MBB emissivity index (phenomenological) Emission-line ratios (line_ratios_table.ecsv) Every line ratio / EW behind the paper's diagnostic diagrams: the BPT and He II diagrams, the Balmer decrement, and the Mg II 2796 EW vs. O32 diagram. Quantity Unit Definition Diagram O3_Hb — [O III] λ5008 / Hβ y-axis of every BPT panel N2_Ha — [N II] λ6585 / Hα [N II] BPT x-axis S2_Ha — ([S II] λ6718 + λ6732) / Hα [S II] BPT x-axis O1_Ha — [O I] λ6302 / Hα [O I] BPT x-axis HeII_Hb — He II λ4687 / Hβ He II diagram y-axis HaHb_narrow — Hα / Hβ, narrow components Balmer decrement HaHb_broad — Hα / Hβ, composite broad components Balmer decrement O32 — [O III] λ5008 / [O II] λ3727 Mg II EW vs. O32 x-axis EW_MgII_2796 Å (rest) Rest-frame EW of the Mg II λ2796 line Mg II EW vs. O32 y-axis Column layout Most quantities Q have four columns encoding three mutually exclusive states. Exactly one group is populated per object, so no separate flag is needed (the two Balmer decrements and EW_MgII_2796 have only three columns; see below): Column Populated when… Description Q detection the value (log₁₀ ratio, Hα/Hβ decrement, or Mg II EW in Å) Q_err_low detection asymmetric 1σ low error (16th-percentile side) Q_err_high detection asymmetric 1σ high error (84th-percentile side) Q_uplim / Q_lolim non-detection the 3σ limit on the quantity Detection — the value + error columns are filled; the limit column is blank. Limit — only the _uplim / _lolim column is filled. Not measured — all four columns are blank (no spectral coverage). Read back as NaN. Caveats An object with a measured Mg II amplitude over a negative fitted local continuum has an undefined EW (EW = flux / continuum); such objects are reported as not measured for EW_MgII_2796. Auxiliary lines (lines_table.ecsv) Direct lmfit Gaussian fits to 25 emission lines. Lines included Group Lines (release key) Single lines NeIII_3869, H8_3889, Hdelta_4102, FeII_4289, FeII_4417, OI_6300, OI_6364, HeI_7065, FeII_5159, HeII_4686 Mg II λλ2796,2803 MgII_2796, MgII_2803 [O II] λλ3727,3729 OII_3727, OII_3729 [S II] λλ6717,6731 SII_6717, SII_6731 [S III] λλ9069,9531 SIII_9069, SIII_9531 [Ne III] + Hε NeIII_3967, Hepsilon_3970 Hγ + [O III] λ4363 Hgamma_4341, OIII_4363 Hγ + [O III] λ4363, Fe II-corrected Hgamma_4341_feii, OIII_4363_feii, FeII_4360_feii The Hγ + [O III] λ4363 is fit in two ways for objects without/with Fe II blend: without an Fe II component and with one. The second carries a _feii suffix. Use whichever fit is appropriate for your analysis; do not mix the two. Columns Each line <key> has four columns: Column Unit Description <key>_ampl 10⁻¹⁷ erg s⁻¹ cm⁻² Å⁻¹ Flux <key>_ampl_err 10⁻¹⁷ erg s⁻¹ cm⁻² Å⁻¹ 1σ flux error <key>_fwhm km s⁻¹ Line FWHM (Doublets share FWHM) <key>_fwhm_err km s⁻¹ 1σ FWHM error Local SDSS comparison LRDs (sdss_local_lrds.ecsv) Three z = 0.1–0.3 SDSS-selected Little Red Dots (Lin+26, https://arxiv.org/pdf/2507.10659) used throughout the paper as a low-redshift comparison sample: J1025+1402, J1047+0739,J1022+0841. They are not part of the DESI DR1 sample, so they have their own small standalone table (3 rows). Columns mirror the relevant parts of master_table.ecsv and line_ratios_table.ecsv so the three objects can be over-plotted on the DESI sample with no schema translation. Column group Columns Unit Identity shortname, z — UV magnitude M_UV (+_err_low/_err_high) mag Continuum shape lambda_v Å (rest) k_blue, k_red, balmer_break — Modified BB lambda_peak, T_peak, T_MB Å / K / K logL_bb log₁₀(erg s⁻¹) beta_MB — Line ratios log_O3_Hb, log_N2_Ha, log_S2_Ha, log_O1_Ha, log_HeII_Hb — Balmer decrement HaHb_narrow, HaHb_broad — Spectra The 27 combined spectra ship as DESI-DR1-spec.zip, which unzips to a DESI-DR1-spec/ folder holding one FITS file per object, named by short ID, e.g. DESI-DR1-spec/DESI_J1717+3807.fits. All 27 spectra come from the DESI DR1 (iron) reduction, the public release the paper is built on. Each file has: PRIMARY — header-only, with metadata:SHRTNAME, IAUNAME, TARGETID (DESI), RA, DEC (deg, ICRS), Z (spectroscopic redshift), TIER, REDUX, FLUXUNIT, WAVEUNIT. SPECTRUM — a binary table with one row per pixel: Column Unit Description WAVE Å (vacuum, observed frame) Wavelength, uniform 0.8 Å grid, 3600–9824 Å (7781 px) FLUX 10⁻¹⁷ erg s⁻¹ cm⁻² Å⁻¹ Flux density FLUX_ERR 10⁻¹⁷ erg s⁻¹ cm⁻² Å⁻¹ 1σ uncertainty IVAR (10⁻¹⁷ erg s⁻¹ cm⁻² Å⁻¹)⁻² Inverse variance (canonical statistical weight) MASK — 0 = good, 1 = masked / no coverage The native DESI B, R, Z cameras share a common 0.8 Å wavelength solution, so they are co-added here by inverse-variance weighting withno interpolation (identical to desispec.coaddition.coadd_cameras). Camera overlap regions therefore have higher S/N than the adjacent single-camera regions. Masked / uncovered pixels are NaN in FLUX and FLUX_ERR (so a naive plot simply gaps them) while IVAR = 0 remains the correct weight for fitting. Spectra are not corrected for Galactic extinction and are in the observed frame; the redshift for de-redshifting is in the header (and inmaster_table.ecsv). Provenance Every value in these tables is taken directly from the measurements and fitted models of the paper: the joint-MCMC emission-line decomposition, the Voigt-profile Balmer-absorption fits, the broken-power-law continuum fits, and the modified-blackbody fits described there. DESI DR1 are publicly available from the DESI database (https://data.desi.lbl.gov/); this release simply repackages. License Released under CC BY 4.0. You are free to share and adapt with attribution to the paper and this record. Contact Xiaojing Lin — [e-mail]