J/ApJS/259/55ivo://CDS.VizieR/J/ApJS/259/55doi:10.26093/cds/vizier.22590055CDSNarendra A.Gibson S.J.Dainotti M.G.Bogdan M.Pollo A.Liodakis I.,Poliszczuk A.Rinaldi E.2022-08-26T08:04:48Z2022-07-19T08:33:14ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.fractive-galactic-nucleigamma-ray-astronomyastronomical-modelsredshiftedMeasuring the redshift of active galactic nuclei (AGNs) requires the use of time-consuming and expensive spectroscopic analysis. However, obtaining redshift measurements of AGNs is crucial as it can enable AGN population studies, provide insight into the star formation rate, the luminosity function, and the density rate evolution. Hence, there is a requirement for alternative redshift measurement techniques. In this project, we aim to use the Fermi Gamma-ray Space Telescope's 4LAC Data Release 2 catalog to train a machine-learning (ML) model capable of predicting the redshift reliably. In addition, this project aims at improving and extending with the new 4LAC Catalog the predictive capabilities of the ML methodology published in Dainotti et al. Furthermore, we implement feature engineering to expand the parameter space and a bias correction technique to our final results. This study uses additional ML techniques inside the ensemble method, the SuperLearner, previously used in Dainotti et al. Additionally, we also test a novel ML model called Sorted L-One Penalized Estimation. Using these methods, we provide a catalog of estimated redshift values for those AGNs that do not have a spectroscopic redshift measurement. These estimates can serve as a redshift reference for the community to verify as updated Fermi catalogs are released with more redshift measurements.2022ApJS..259...55Nhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/259/55CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIX/67 : Incremental Fermi LAT 4th source cat. (4FGL-DR3) (Fermi-LAT col., 2022)J/ApJ/690/1236 : COSMOS photometric redshift catalog (Ilbert+, 2009)J/A+A/523/A48 : Gaia photometry (Jordi+, 2010)J/ApJ/774/157 : Swift GRBs with X-ray afterglows and z<9.5 (Dainotti+, 2013)J/MNRAS/428/220 : Gamma-ray AGN type determination (Hassan+, 2013)J/MNRAS/437/968 : AGN automatic photometric classification (Cavuoti+, 2014)J/ApJ/782/41 : 231 AGN candidates from the 2FGL catalog (Doert+, 2014)J/MNRAS/462/3180 : 3FGL Blazar of Unknown Type classification (Chiaro+, 2016)J/A+A/602/A86 : Blazar cand. among Fermi/LAT 3FGL cat. (Lefaucheur+, 2017)J/AJ/154/269 : A new photo-z method for quasars in Stripe 82 (Yang+, 2017)J/A+A/619/A14 : Classification-aided zph estimation (Fotopoulou+, 2018)J/A+A/611/A97 : Phot. quasar candidates in Stripe 82 (Pasquet-Itam+, 2018)J/ApJS/247/33 : Fermi LAT fourth source catalog (4FGL) (Abdollahi+, 2020)J/ApJ/892/105 : 4th cat. of Fermi LAT-detected AGNs (4LAC) (Ajello+, 2020)J/A+A/633/A154 : HDBSCAN star, galaxy, QSO classification (Logan+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/259/55https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/259/55http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/259/55https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/259/55https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/259/55http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/259/55GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/259/55/table3 (List of predictions for the generalization set)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/259/55/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/259/55/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/259/55/table3?GETtext/xml+votable180.050000true0.3151-7.79710.0055555555555555566/267 447 770 851 898 1120 1222 1622 1915 2028 2066 2078 2122 2295 2460 2484 2505 2808 3023 3096 3338 3465 3492 3566 3616 3629 3667 3700 3876 3882 3974 4312 4685 4746 5195 5536 5553 5614 5673 5990 6132 6404 6406 6458 6515 6723 6815 6822 6888 6940 7091 7212 7235 7319 7411 7448 7475 7530 7640 7655 7758 7808 7936 8100 8177 8615 9175 9196 9566 9618 10046 10067 10170 10280 10435 10512 10524 10526 10825 11012 11153 11212 11321 11396 11456 11975 12197 12231 12323 12385 12666 12902 13204 13406 13447 13613 13666 13743 13826 13867 14751 14797 14857 14976 15037 15211 15269 15783 15916-15917 15955 15996 16057 16170 16510 16736 16816 17048 17347 17617 17732 17910 18046 18190 18210 18889 19037 19149 19325 19523 19525 19616 19786 19843 19890 19907 19999 20020 20049 20141 20577 20836 20908 20920 21073 21217 21574 21704 21711 21793 21855 22372 22615 23105 23825 23932 24099 24112 24140 24566 24635 24980 25184 25239 25386 25539 26056 26254 26256 26483 26550 26565 26614 26695 26798 27021 27082 27138 27311 27423 27554 27669 27772 27866 28037 28542 29598 29729 30012 30196 30565 30570 30573 30928 31011 31362 31535 31763 31773 31967 32034 32050 32185 32247 32370 32495 32596 32605 32712 32904 33040 33198 33296 33356 33412 33512 33528 33744 33746 34085 34252 34528 35063 35146 35252 35501 35701 35722 35765 35786 35790 36063 36295 36719 36813 36842 36882 37045 37492 37529 37779 37994 38486 38918 39210 39505 39544 39570 39752 39978 40692 40703 40766 40874 40885 41033 41051 41345 41363 41574 42481 42571 42914 43122 43225 43399 43596-43597 43643 43805 43877 44059 44113 44153 44170 44193 44539 44554 44582 44661 44669 44911 45011 45316 45482 46285 46394 46568 46740 46872 47046 47154 47248 47382 47398 47413 47708 47714 48121 48187 48528 48829 49037 49068 49142https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/259/55?format=asciiGamma-raydefaultJ/ApJS/259/55/table3List of predictions for the generalization setrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint4FGL4FGL identifier (JHHMM.m+DDMM)meta.id;meta.maincharzPred[0.14/1.02] Predicted redshift (1)src.redshift;meta.modelledfloatzCor[-0.06/1.34] Bias-corrected, predicted redshiftsrc.redshift;meta.modelledfloat4LACDisplay data from the 4LAC (Ajello+, 2020, J/ApJ/892/105)meta.ref.urlintnullableSimbadSimbad column added by the CDSmeta.ref.urlcharNEDNED column added by the CDSmeta.ref.urlchar_RAPositions from 4FGL DR3 (Cat. IX/67) (right ascension part)degpos.eq.ra;meta.main_DEPositions from 4FGL DR3 (Cat. IX/67) (declination part)degpos.eq.dec;meta.main