J/ApJS/282/20 The J-HERTz catalog from J-PLUS & LoTSS (Fernandez Gil+, 2026)
J-HERTz: J-PLUS Heritage Exploration of Radio Targets at z<5.
Fernandez Gil D., Fernandez-Ontiveros J.A., Lopez-Sanjuan C.,
Arizo-Borillo F., del Pino A., Hernan-Caballero A., Lumbreras-Calle A.,
Rahna P.T., Sobral D., Ramio H.V., Cenarro A.J., Marin-Franch A.,
Angulo R.E., Ederoclite A., Cristobal-Hornillos D., Dupke R.A.,
Hernandez-Monteagudo C., Moles M., Sodre L.J., Varela J.
<Astrophys. J. Suppl. Ser., 282, 20 (2026)>
=2026ApJS..282...20F 2026ApJS..282...20F
ADC_Keywords: Radio sources; Redshifts; Photometry, infrared; Optical; QSOs;
Active gal. nuclei; Stars, radio; Galaxies, radio
Keywords: Catalogs ; Active galactic nuclei ; Radio galaxies ; Quasars ;
Galaxy quenching ; Stellar types
Abstract:
We introduce J-HERTz (J-PLUS Heritage Exploration of Radio Targets at
z<5), a new multiwavelength catalog that combines optical narrowband
photometry from J-PLUS, infrared observations from the Wide-field
Infrared Survey Explorer, and deep low-frequency radio data from LoTSS
for nearly 0.5 million sources across 2100 deg2 of the northern sky.
Key innovations of J-HERTz include Bayesian neural network
classifications for 390,000 galaxies, 31,000 quasars, and
20,000 stars, along with significantly improved photometric redshifts
for 235,000 galaxies compared to previous J-PLUS DR3 and LoTSS DR2
estimates. We identify 831 candidate Galactic radio stars, which, if
confirmed, would constitute a significant addition to the number of
radio-emitting stars identified to date. Among radio-loud galaxies
with spectroscopic observations, ≳20% lack Seyfert or LINER
signatures, indicating a substantial population of optically quiescent
radio galaxies, in agreement with previous works. Spectral energy
distribution fitting of their host galaxies using J-PLUS photospectra
reveals systematically low specific star formation rates, consistent
with quenched stellar populations. J-HERTz thus provides a powerful
data set to exploit radio-optical synergies, enabling studies that
span from the origin of stellar radio emission to the active galactic
nucleus life cycle and the role of jet activity in shaping host galaxy
evolution.
Description:
The J-HERTz (J-PLUS Heritage Exploration of Radio Targets at z<5)
catalog contains 489,897 objects found in J-PLUS DR3 and LoTSS DR2.
The Javalambre Photometric Local Universe Survey (J-PLUS) DR3 catalog
covers about ∼3200deg2 of the northern sky, containing ∼47 million
objects between galaxies, QSOs, and stars. The observations are done
at the Observatorio Astrofisico de Javalambre with the Javalambre
Auxilary Survey Telescope of 83cm diameter (JAST80) and T80Cam. It has
12 filters, a combination of five broad and seven medium or narrow
bands covering ∼3400-9200Å.
The LOw Frequency ARray (LOFAR) Two-meter Sky Survey (LoTSS) DR2
(Shimwell+ 2022, J/A+A/659/A1) is a low-frequency radio catalog that
provides fluxes at 144MHz with a 6" resolution.
There are available spectroscopic redshifts for ∼34% of our sources,
mainly from SDSS and DESI, and photometric redshift estimates based on
broad bands for ∼95% of sources in LoTSS and narrow bands for ∼97% of
sources in J-PLUS. See Section 2.7.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table4.dat 1017 492537 The full J-HERTz catalog
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Description of file:
datafile4.fits.gz is the original FITS file as downloaded in the Appendix
See also:
III/250 : The VIMOS VLT deep survey (VVDS-DEEP) (Le Fevre+ 2005)
I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)
II/365 : The CatWISE2020 cat. (updated version 28-Jan-2021) (Marocco+, 2021)
VIII/40 : GB6 catalog of radio sources (Gregory+ 1996)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
VIII/78 : Sydney University Molonglo Sky Survey (SUMSS) (Mauch+ 2006)
VIII/79 : The VLA Low-frequency Sky Survey at 74MHz (Cohen+ 2007)
VIII/81 : Sydney University Molonglo Sky Survey (SUMSS V2.1) (Mauch+ 2008)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
VIII/100 : GaLactic and Extragalactic All-sky MWA survey (Hurley-Walker+, 2016)
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
VII/292 : DESI Legacy Imaging Surveys DR8 photometric redshifts (Duncan, 2022)
J/ApJS/95/1 : Atlas of Quasar Energy Distributions (Elvis+ 1994)
J/A+AS/124/259 : Westerbork Northern Sky Survey I. (Rengelink+ 1997)
J/ApJS/126/133 : The FIRST bright quasar survey. II. (White+, 2000)
J/MNRAS/341/993 : ujbr photometry and redshifts of QSOs (Cirasuolo+, 2003)
J/MNRAS/375/931 : Radio sources in the 6dFGS (Mauch+, 2007)
J/MNRAS/438/1149 : WISE data for radio-loud AGNs (Gurkan+, 2014)
J/ApJ/831/168 : 6GHz JVLA obs. of low-z SDSS quasars (Kellermann+, 2016)
J/MNRAS/464/1306 : LARGESS survey (Ching+, 2017)
J/ApJ/861/49 : ALFALFA extragalactic HI source catalog (Haynes+, 2018)
J/ApJS/238/9 : Cat. of giant radio sources known to date (Kuzmicz+, 2018)
J/A+A/628/A69 : LOFAR 143MHz images of 3C 236 (Shulevski+, 2019)
J/A+A/643/A149 : J-PLUS Lyα-emitting candidates (Spinoso+, 2020)
J/A+A/648/A104 : LOFAR LBA Sky Survey. I. (de Gasperin+, 2021)
J/other/PASA/38.58 : Rapid ASKAP Continuum Survey. II. RACS cat. (Hale+, 2021)
J/PASJ/73/313 : Radio loudness and classif. for radio source (Zhang+, 2021)
J/A+A/668/A60 : Extreme em. line galaxies in J-PLUS (Lumbreras-Calle+, 2022)
J/A+A/659/A1 : LOFAR Two-metre Sky Survey (LoTSS) DR2 (Shimwell+, 2022)
J/A+A/678/A151 : LoTSS DR2 optical IDs (Hardcastle+, 2023)
J/A+A/691/A221 : J-PLUS Bayesian object classification (del Pino+, 2024)
J/other/PASA/41.84 : Sydney Radio Star Catalogue (Driessen+, 2024)
J/A+A/695/A200 : J-PLUS Halpha emission line maps of galaxies (Rahna+, 2025)
http://www.j-plus.es/datareleases/data_release_dr3 : J-PLUS DR3 homepage
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- TileID [84109/104004] Tile ID of the
reference r-band image (TILE_ID)
8- 12 I5 --- ID [1/92409] Number ID assigned by
SExtractor (NUMBER)
14- 35 A22 --- Source Object identifier (ILT name) in
LoTSS (Source_name)
37- 47 F11.7 deg RAdeg Radio right ascension from LoTSS
(ICRS) (RA)
49- 58 F10.7 deg DEdeg [16/69.2] Radio decl. from LoTSS
(ICRS) (Decl)
60- 70 F11.7 deg RAOdeg R.A. of the optical/IR
counterpart (Opt_RA) (1)
72- 81 F10.7 deg DEOdeg Decl. of the optical/IR
counterpart (Opt_DEC) (1)
83- 89 F7.5 arcsec Dist [0.0003/5] Angular distance
optical/IR vs J-PLUS (ang_Dist)
91- 99 F9.3 mJy F144MHz [0.16/81276] 144MHz total flux
density from LoTSS (Total_flux)
101- 107 F7.3 mJy e_F144MHz [0.05/968] Error on F144MHz
density from LoTSS (ETotalflux)
109- 118 F10.5 arcsec LAS [0/2406] Radio angular size
estimate from LoTSS (LAS)
120 I1 --- Res [0/1] Resolved flag from LoTSS
(Resolved)
122- 128 F7.4 --- Pgal [-0.4/1.1] Mean probability of
being a galaxy (CLASSGALAXYmean)
130- 136 F7.4 --- Pqso [-0.05/1.1] Mean probability of
being a QSO (CLASSQSOmean)
138- 144 F7.4 --- Pstar [-0.1/1.5] Mean probability of
being a star (CLASSSTARmean)
146- 151 F6.4 --- e_Pgal [0.02/0.7] Std deviation of
galaxy probability
(CLASSGALAXYstd)
153- 158 F6.4 --- e_Pqso [0.005/0.7] Std deviation of QSO
probability (CLASSQSOstd)
160- 165 F6.4 --- e_Pstar [0.02/0.7] Std deviation of star
probability (CLASSSTARstd)
167- 173 F7.4 --- zphLoTSS [-1.6/6.4]? Photo-z estimate from
LoTSS (LoTSS_zphot)
175- 180 F6.4 --- e_zphLoTSS [0.0069/4.9]? Photo-z error from
LoTSS (LoTSSzphoterr)
182- 189 F8.1 --- q_zphot [0/1]? Predicted photo-z quality,
0=bad,1=good (flag_qual)
191- 199 F9.5 --- zphJPLUS [0/1]? Photo-z estimate from
J-PLUS (JPLUS_zphot)
201- 207 F7.5 --- e_zphJPLUS [0/0.5]? Photo-z error from
J-PLUS (JPLUSzphoterr)
209- 214 F6.4 --- ODDS [0/1]? Prob of J-PLUS photo-z
rel. error < 0.03 (ODDS)
216- 222 F7.5 --- zphot [0.005/1]? Combined photo-z from
J-PLUS and LoTSS (Combined_zphot)
224- 230 F7.5 --- e_zphot [0/0.5]? Combined photo-z error
(Combinedzphoterr)
232- 240 F9.6 --- zspec [-0.005/7.1]? Spectroscopic
redshift from SDSS/DESI/HETDEX
(zspec)
242- 250 F9.6 --- e_zspec [-6/61]? Spectroscopic redshift
error (zspec_err)
252- 260 F9.6 --- zbest [-0.005/5]? Best available
redshift (z_best)
262- 270 F9.6 --- e_zbest [-6/61]? Best available redshift
error (zbesterr)
272- 286 A15 --- r_zbest Source of the best available
redshift (z_source)
288- 296 F9.4 kpc Size [-0.24/4912]? Radio linear size
from LAS using z_best (Size)
298- 308 E11.6 W/Hz L144MHz [2.1e+11/2.2e+29]? Radio
luminosity from Total_flux using
z_best (L_144)
310- 316 F7.4 --- RL [-2.3/5.5]? Radio-to-IR ratio log
(F144/FW2) (Radio_loudness)
318- 323 F6.3 mag W1mag [10/23]? WISE band 1 magnitude
from LoTSS (mag_w1)
325- 333 E9.4 mag e_W1mag [2.1e-05/0.6]? WISE band 1
magnitude error
(upper limit blank) (magerr_w1)
335- 340 F6.3 mag W2mag [9.99/22.1]? WISE band 2
magnitude from LoTSS (mag_w2)
342- 350 E9.4 mag e_W2mag [4.4e-05/0.6]? WISE band 2
magnitude error
(upper limit blank) (magerr_w2)
352- 357 F6.3 mag W3mag [9/19.4]? WISE band 3 magnitude
from LoTSS (mag_w3)
359- 367 E9.4 mag e_W3mag [0.0002/0.6]? WISE band 3
magnitude error
(upper limit blank) (magerr_w3)
369- 374 F6.3 mag W4mag [7.2/17.1]? WISE band 4 magnitude
from LoTSS (mag_w4)
376- 384 E9.4 mag e_W4mag [0.0003/0.6]? WISE band 4
magnitude error
(upper limit blank) (magerr_w4)
386- 395 E10.5 Msun Ms [0/9.2e+14]? Stellar mass from
CIGALE for z_best (Stellar_mass)
397- 406 E10.5 Msun e_Ms [0/2.7e+14]? Stellar mass error
from CIGALE for z_best
(Stellarmasserr)
408- 417 E10.5 Msun/yr SFR [0/94017]? Star formation rate
from CIGALE for z_best (SFR)
419- 428 E10.5 Msun/yr e_SFR [0/33342]? Star formation rate
error from CIGALE for z_bes
(SFR_err)
430- 439 E10.5 Msun/yr SFR10Myrs [0/58936]? SFR averaged over last
10 Myr from CIGALE (SFR10Myrs)
441- 450 E10.5 Msun/yr e_SFR10Myrs [0/31591]? Error on SFR10Myrs
from CIGALE (SFR10Myrs_err)
452- 461 E10.5 Msun/yr SFR100Myrs [0/34519]? SFR averaged over last
100 Myr from CIGALE (SFR100Myrs)
463- 472 E10.5 Msun/yr e_SFR100Myrs [0/59810]? Error on SFR100Myrs
from CIGALE (SFR100Myrs_err)
474 I1 --- Close [0/1] Object closer than 5 arcsec
(1=yes) (close_objects)
476- 481 F6.4 --- SpInc [0/1]? Spec class incompatible
with BANNJOS (1=yes)
(incompatiblespecclass)
483- 488 F6.4 --- zspUnr [0/1]? Unreliable spectroscopic
redshift (1=yes)
(unreliablespecz)
490- 499 A10 --- RadStar Potential radio star candidate
(candidateradiostar)
501 I1 --- ClUmb [0/1] Several BANNJOS class.
(1=yes) (ambiguous_classification)
503- 517 E15.9 10-19cW/m2/nm Fu [-13450/7.2e+07] AUTO flux density
in J-PLUS u band
in 10-19erg/cm2/s/Angstrom
(FLUXAUTOLambda_u) (2)
519- 533 E15.9 10-19cW/m2/nm FJ0378 AUTO flux density in J-PLUS J0378
band in 10-19erg/cm2/s/Angstrom
(FLUXAUTOLambda_J0378) (2)
535- 549 E15.9 10-19cW/m2/nm FJ0395 AUTO flux density in J-PLUS J0395
band in 10-19erg/cm2/s/Angstrom
(FLUXAUTOLambda_J0395) (2)
551- 565 E15.9 10-19cW/m2/nm FJ0410 AUTO flux density in J-PLUS J0410
band in 10-19erg/cm2/s/Angstrom
(FLUXAUTOLambda_J0410) (2)
567- 581 E15.9 10-19cW/m2/nm FJ0430 AUTO flux density in J-PLUS J0430
band in 10-19erg/cm2/s/Angstrom
(FLUXAUTOLambda_J0430) (2)
583- 597 E15.9 10-19cW/m2/nm Fg AUTO flux density in J-PLUS g
band in 10-19erg/cm2/s/Angstrom
(FLUXAUTOLambda_g) (2)
599- 613 E15.9 10-19cW/m2/nm FJ0515 AUTO flux density in J-PLUS J0515
band in 10-19erg/cm2/s/Angstrom
(FLUXAUTOLambda_J0515) (2)
615- 629 E15.9 10-19cW/m2/nm Fr AUTO flux density in J-PLUS r
band in 10-19erg/cm2/s/Angstrom
(FLUXAUTOLambda_r) (2)
631- 645 E15.9 10-19cW/m2/nm FJ0660 AUTO flux density in J-PLUS J0660
band in 10-19erg/cm2/s/Angstrom
(FLUXAUTOLambda_J0660) (2)
647- 661 E15.9 10-19cW/m2/nm Fi AUTO flux density in J-PLUS i
band in 10-19erg/cm2/s/Angstrom
(FLUXAUTOLambda_i) (2)
663- 677 E15.9 10-19cW/m2/nm FJ0861 AUTO flux density in J-PLUS J0861
band in 10-19erg/cm2/s/Angstrom
(FLUXAUTOLambda_J0861) (2)
679- 693 E15.9 10-19cW/m2/nm Fz AUTO flux density in J-PLUS z
band in 10-19erg/cm2/s/Angstrom
(FLUXAUTOLambda_z) (2)
695- 708 E14.8 10-19cW/m2/nm e_Fu [-774/865] Relative errors of the
u-band AUTO flux density
(FLUXRELERRAUTOLambdau)
710- 723 E14.8 10-19cW/m2/nm e_FJ0378 [-65504/45184] Relative errors of
the J0378 AUTO flux density
(FLUXRELERRAUTOLambdaJ0378)
725- 738 E14.8 10-19cW/m2/nm e_FJ0395 [-1192/65504] Relative errors of
the J0395 AUTO flux density
(FLUXRELERRAUTOLambdaJ0395)
740- 753 E14.8 10-19cW/m2/nm e_FJ0410 [-17760/65504] Relative errors of
the J0410 AUTO flux density
(FLUXRELERRAUTOLambdaJ0410)
755- 768 E14.8 10-19cW/m2/nm e_FJ0430 [-65504/65504] Relative errors of
the J0430 AUTO flux density
(FLUXRELERRAUTOLambdaJ0430)
770- 783 E14.8 10-19cW/m2/nm e_Fg [-65504/65504] Relative errors of
the g-band AUTO flux density
(FLUXRELERRAUTOLambdag)
785- 798 E14.8 10-19cW/m2/nm e_FJ0515 [-65504/65504] Relative errors of
the J0515 AUTO flux density
(FLUXRELERRAUTOLambdaJ0515)
800- 813 E14.8 10-19cW/m2/nm e_Fr [-65504/65504] Relative errors of
the r-band AUTO flux density
(FLUXRELERRAUTOLambdar)
815- 828 E14.8 10-19cW/m2/nm e_FJ0660 [-65504/28336] Relative errors of
the J0660 AUTO flux density
(FLUXRELERRAUTOLambdaJ0660)
830- 843 E14.8 10-19cW/m2/nm e_Fi [-17616/65504] Relative errors of
the i-band AUTO flux density
(FLUXRELERRAUTOLambdai)
845- 858 E14.8 10-19cW/m2/nm e_FJ0861 [-26960/4488] Relative errors of
the J0861 AUTO flux density
(FLUXRELERRAUTOLambdaJ0861)
860- 873 E14.8 10-19cW/m2/nm e_Fz [-8004/5884] Relative errors of
the z-band AUTO flux density
(FLUXRELERRAUTOLambdaz)
875- 882 E8.3 --- Flu [0/2052] SExtractor flag for
J-PLUS u-band (FLAGS_u)
884- 891 E8.3 --- FlJ0378 SExtractor flag for J-PLUS J0378
band (FLAGS_J0378)
893- 900 E8.3 --- FlJ0395 SExtractor flag for J-PLUS J0395
band (FLAGS_J0395)
902- 909 E8.3 --- FlJ0410 SExtractor flag for J-PLUS J0410
band (FLAGS_J0410)
911- 918 E8.3 --- FlJ0430 SExtractor flag for J-PLUS J0430
band (FLAGS_J0430)
920- 927 E8.3 --- Flg SExtractor flag for J-PLUS g-band
(FLAGS_g)
929- 936 E8.3 --- FlJ0515 SExtractor flag for J-PLUS J0515
band (FLAGS_J0515)
938- 945 E8.3 --- Flr SExtractor flag for J-PLUS r-band
(FLAGS_r)
947- 954 E8.3 --- FlJ0660 SExtractor flag for J-PLUS J0660
band (FLAGS_J0660)
956- 963 E8.3 --- Fli SExtractor flag for J-PLUS i-band
(FLAGS_i)
965- 972 E8.3 --- FlJ0861 SExtractor flag for J-PLUS J0861
band (FLAGS_J0861)
974- 981 E8.3 --- Flz SExtractor flag for J-PLUS z-band
(FLAGS_z)
983- 984 I2 --- Mku Mask flag for J-PLUS u band
(MASKFLAGSu)
986- 987 I2 --- MkJ0378 Mask flag for J-PLUS J0378 band
(MASKFLAGSJ0378)
989- 990 I2 --- MkJ0395 Mask flag for J-PLUS J0395 band
(MASKFLAGSJ0395)
992- 993 I2 --- MkJ0410 Mask flag for J-PLUS J0410 band
(MASKFLAGSJ0410)
995- 996 I2 --- MkJ0430 Mask flag for J-PLUS J0430 band
(MASKFLAGSJ0430)
998- 999 I2 --- Mkg Mask flag for J-PLUS g band
(MASKFLAGSg)
1001- 1002 I2 --- MkJ0515 Mask flag for J-PLUS J0515 band
(MASKFLAGSJ0515)
1004- 1005 I2 --- Mkr Mask flag for J-PLUS r band
(MASKFLAGSr)
1007- 1008 I2 --- MkJ0660 Mask flag for J-PLUS J0660 band
(MASKFLAGSJ0660)
1010- 1011 I2 --- Mki Mask flag for J-PLUS i band
(MASKFLAGSi)
1013- 1014 I2 --- MkJ0861 Mask flag for J-PLUS J0861 band
(MASKFLAGSJ0861)
1016- 1017 I2 --- Mkz Mask flag for J-PLUS z band
(MASKFLAGSz)
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Note (1): We use the optical/IR identifications of LoTSS provided by
Hardcastle+ (2023, J/A+A/678/A151). See Section 2.4.
Note (2): J-PLUS photometric system as in Table 1:
------------------------------------
Filter lambdacen FWHM
Å Å
------------------------------------
u 3485 508
J0378 3785 168
J0395 3950 100
J0410 4100 200
J0430 4300 200
g 4803 1409
J0515 5150 200
r 6254 1388
J0660 6600 138
i 7668 1535
J0861 8610 400
z 9114 1409
------------------------------------
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History:
From electronic version of the journal
License: CC-BY-4.0
(End) Emmanuelle Perret [CDS] 13-Jul-2026