J/other/ApSS/371.85 Ultracool and brown dwarf candidates (Majaess+, 2026) ================================================================================ Ultracool and brown dwarf candidates identified via CatWISE-2MASS-Gaia DR3. Majaess D., Minniti D., Gomez M., Saito R.K., Navarros M.G. =2026Ap+SS.371...85M (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Stars, brown dwarf ; Stars, M-type ; Photometry, infrared ; Optical ; Parallaxes, trigonometric ; Proper motions Keywords: Brown dwarfs - M dwarf stars Abstract: Ultracool and brown dwarf candidates (d_{sun}_<=125pc, |b|>8deg) were identified via multiband and astrometric data from CatWISE (W1, W2), 2MASS (J, H, Ks), and Gaia DR3 (G, G_RP_, parallax, proper motions). N~11.8x10^3^ candidates emerged once simultaneously constrained by color and absolute magnitude criteria (e.g., G-W2>=1.75(G-J)-2.25), whereby ~350 sources are absent from the Gaia Ultracool Dwarf (UCD) catalog. Spectral types were approximated using a hybrid M_G_-M_W1_ sigmoid that offers additional temperature coverage in certain cases. Subsequent efforts may focus on extending sampling to the deeper NIR VVVX footprint that partly encompasses the Galactic plane, and over the long-term spectroscopically (in)validating candidates missing from the Gaia UCD database. Description: Photometric and astrometric parameters, along with estimated spectral types and cross-match designations, for ultracool and brown dwarf candidates. The candidates were identified by pairing MIR CatWISE, NIR 2MASS, and optical Gaia DR3 data. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file catalog.dat 293 11749 Catalog of ultracool and brown dwarf candidates -------------------------------------------------------------------------------- See also: I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022) II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) II/365 : The CatWISE2020 catalog (Marocco+, 2021) J/A+A/619/L8 : Ultra-cool dwarfs candidates in Gaia DR2 (Reyle, 2018) J/MNRAS/485/4423 : The Gaia ultracool dwarf sample (Smart+, 2019) J/A+A/669/A139 : Ultracool dwarfs in Gaia DR3 (Sarro+, 2023) J/A+A/670/A19 : Fifth Catalogue of Nearby Stars (CNS5) (Golovin+, 2023) Byte-by-byte Description of file: catalog.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 19 I19 --- GaiaDR3 Gaia DR3 unique source identifier (gaia_id) 21- 30 F10.6 deg RAdeg Right Ascension (ICRS) at Ep=2016.0 (ra) 32- 41 F10.6 deg DEdeg Declination (ICRS) at Ep=2016.0 (dec) 43- 52 F10.6 deg GLON Galactic Longitude (l_gal) 54- 63 F10.6 deg GLAT Galactic Latitude (b_gal) 65- 71 F7.4 mas Plx Absolute stellar parallax from Gaia DR3 (parallax) 73- 78 F6.4 mas e_Plx Parallax uncertainty (parallax_err) 80- 87 F8.4 --- RPlx Parallax over error (signal-to-noise) (parallax_over_err) 89- 96 F8.3 mas/yr pmRA Proper motion in Right Ascension (Gaia DR3) (pm_ra) 98-102 F5.3 mas/yr e_pmRA Proper motion uncertainty in Right Ascension (pm_ra_err) 104-112 F9.3 mas/yr pmDE Proper motion in Declination (Gaia DR3) (pm_dec) 114-118 F5.3 mas/yr e_pmDE Proper motion uncertainty in Declination (pm_dec_err) 120-125 F6.3 mag Gmag Gaia DR3 G-band apparent magnitude (app_g) 127-131 F5.3 mag e_Gmag Gaia DR3 G-band magnitude uncertainty (app_g_err) 133-138 F6.3 mag Rpmag Gaia DR3 GRP-band apparent magnitude (app_rp) 140-144 F5.3 mag e_Rpmag Gaia DR3 GRP-band magnitude uncertainty (app_rp_err) 146-161 A16 --- 2MASS 2MASS point source catalog identifier (2mass_id) 163-168 F6.3 mag Jmag 2MASS J-band apparent magnitude (app_j) 170-174 F5.3 mag e_Jmag 2MASS J-band magnitude uncertainty (app_j_err) 176-181 F6.3 mag Hmag 2MASS H-band apparent magnitude (app_h) 183-187 F5.3 mag e_Hmag 2MASS H-band magnitude uncertainty (app_h_err) 189-194 F6.3 mag Kmag 2MASS Ks-band apparent magnitude (app_k) 196-200 F5.3 mag e_Kmag 2MASS Ks-band magnitude uncertainty (app_k_err) 202-204 A3 --- 2MASSqflg 2MASS photometric quality flag (e.g., AAA) (2mass_qflg) 206-224 A19 --- CatWISE CatWISE catalog identifier (catwise_id) 226-231 F6.3 mag W1mag CatWISE W1-band apparent magnitude (app_w1) 233-237 F5.3 mag e_W1mag CatWISE W1-band magnitude uncertainty (app_w1_err) 239-244 F6.3 mag W2mag CatWISE W2-band apparent magnitude (app_w2) 246-250 F5.3 mag e_W2mag CatWISE W2-band magnitude uncertainty (app_w2_err) 252-270 A19 --- CatMatch Cross-match presence in external catalogs (UCD, R18, S19, CNS5) (catalog_match) (1) 272-278 F7.1 K TeffUCD ? Effective temperature from the Gaia UCD catalog (teff_UCD) 280-285 F6.1 K e_TeffUCD ? Effective temperature uncertainty (Gaia UCD) (teff_err_UCD) 287-290 A4 --- SpTphR18 ? Photometric spectral type estimate from Reyle (2018A&A...619L...8R, Cat. J/A+A/619/L8) (sptphot_R18) 292-293 A2 --- SpTEst Hybrid MG-MW1 estimated spectral type from this study (SPT_Estimator) -------------------------------------------------------------------------------- Note (1): External catalogs as follows: UCD = Sarro et al., 2023A&A...669A.139S, Cat. J/A+A/669/A139 R18 = Reyle (2018A&A...619L...8R, Cat. J/A+A/619/L8 S19 = Smart et al., 2019MNRAS.485.4423S, Cat. J/MNRAS/485/4423 CNS5 = Golovin et al., 2023A&A...670A..19G, Cat. J/A+A/670/A19 -------------------------------------------------------------------------------- Acknowledgements: Daniel Majaess, daniel.majaess(at)gmail.com License: CC-BY-4.0 ================================================================================ (End) Patricia Vannier [CDS] 21-Aug-2026