J/MNRAS/466/2879ivo://CDS.VizieR/J/MNRAS/466/2879doi:10.26093/cds/vizier.74662879CDSBar R.E.Weigel A.K.Sartori L.F.Oh K.Koss M.Schawinski K.2024-08-17T20:17:48Z2019-11-27T14:46:39ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiredshiftedIn order to perform a more complete census of active galactic nuclei (AGN) in the local Universe, we investigate the use of the HeII {lambda}4685 emission line diagnostic diagram by Shirazi & Brinchmann (2012, Cat. J/MNRAS/421/1043) in addition to the standard methods based on other optical emission lines. The HeII-based diagnostics is more sensitive to AGN ionization in the presence of strong star formation than conventional line diagnostics. We survey a magnitude-limited sample of 63915 galaxies from the Sloan Digital Sky Survey Data Release 7 at 0.02<z<0.05 and use both the conventional BPT emission line diagnostic diagrams, as well as the HeII diagram to identify AGN. In this sample, 1075 galaxies are selected as AGN using the BPT diagram, while additional 234 galaxies are identified as AGN using the HeII diagnostic diagram, representing a 22 per cent increase of AGN in the parent galaxy sample. We explore the host galaxy properties of these new HeII-selected AGN candidates and find that they are most common in star-forming galaxies on the blue cloud and on the main sequence where ionization from star formation is most likely to mask AGN emission in the BPT lines. We note in particular a high He II AGN fraction in galaxies above the high-mass end of the main sequence where quenching is expected to occur. We use archival Chandra observations to confirm the AGN nature of candidates selected through He II-based diagnostic. Finally, we discuss how this technique can help inform galaxy/black hole coevolution scenarios.2017MNRAS.466.2879Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/466/2879CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/466/2879https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/466/2879http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/466/2879https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/466/2879https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/466/2879http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/466/2879GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/466/2879/table1 (All the BPT-selected AGN candidates and additional AGN candidates selected by the HeII method)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/466/2879/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/466/2879/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/466/2879/table1?GETtext/xml+votable180.050000true217.36247-0.20893190.0055555555555555565/1301 4502 6/526 549 555 4107 4109 4130 4157 4162 4188 4199 4202 4218 4252 4262 4272 4291 4304 4310 4314 4339 4348 4364 4369 4371-4372 4376 4407 4409 4416 4424 4428 4432 4437 4445 4450 4476-4477 4496 4511 4514 4517-4519 4521 4531 4541 4543 4546 4550 4552 4556 4567 4586 4591 4608 4613-4614 4630 4650 4660-4661 4688 4718 4727 4730 4739 4743 4748 4750-4751 4762 4767 4774 4799 4822 4830 4833-4835 4847 4851 4859 4881 4906 4920 4927 4929 4931 4943 4947 4961 4964 4967 4972 4990 5016 5033 5046 5061 5087 5112 5123 5128 5130-5131 5135 5149 5151 5169 5172 5175 5184 5203 5215 5219 5221 5223 5229 5238 5261 5280 5293 5338 5343 5347-5348 5350 5359 5362 5372 5375 5377 5383 5389-5390 5394-5395 5400-5402 5419 5422 5424-5425 5450 5457 5461 5463 5469 5486 5493 5501 5505-5506 5508 5510 5514 5525 5536 5557-5559 5564 5566 5572 5585 5592 5594 5600 5604 5616-5618 5620 5629-5630 5645 5647 5660 5662 5674 5684 5696-5698 5701 5703-5704 5729 5736 5744 5752-5754 5782 5796 5806 5822 5838-5839 5848 5864 5879 5907 5912-5913 5918 5922 5924 5927 5930 5935 5945 5955 5959-5960 5963-5964 5995 6004 6010 6015-6016 6026 6056-6057 6059 6084 6113 6119 6121 6124 6129 6134 6140 6208 6211-6212 6224 6232 6239 6254 6269 6417 6427 6438 6444 6446-6447 6451 6455-6458 6474 6476 6481 6491 6501 6553 6568 6571 6576 6579 6581-6582 6587 6602 6613 6638 6643 6645 6992-6993 6996-6997 7184 7197-7199 7218-7219 7222 7244 7249 7257 7261 7266 7273 7276 7303 7307 7313 7318-7319 7321 7324-7325 7331 7337 7347 7349 7354 7361 7365 7390 7424 7442 7452 7456 7466 7489 7517 7528 7531 7538 7554 7560 7696 8195 8203 8208 8211-8213 8215 8219-8220 8223 8226 8230 8247-8248 8250 8253 8257 8261 8264 8266-8270 8275 8278 8281 8288 8291 8297 8300-8301 8308 8310 8315 8343-8344 8346 8357 8365 8368 8373 8377 8386 8399 8413 8419 8430-8431 8434 8436 8442 8445-8446 8449 8453-8454 8467-8470 8475 8487 8505-8507 8513-8514 8517 8524-8525 8533 8541 8543 8545 8547 8553 8560 8569 8574 8581 8602 8607 8614 8617 8626 8631 8641 8646 8650 8662 8667 8674 8679 8684-8685 8690-8691 8694 8702 8712 8721 8727 8737 8742-8744 8746 8761 8779-8781 8787 8790 8792-8793 8796 8803 8805 8820 8822 8827 8830 8841 8843 8846 8852 8870 8890-8891 8917 8938 8940 8947-8948 8952 8957 8968-8969 8973 8987 8992 8996-8997 9000 9004 9026 9032 9040 9088-9089 9101 9111 9113 9120 9122 9132 9135 9143 9150-9151 9163 9178 9218-9219 9229 9254 9261-9262 9266-9267 9286-9288 9294 9333 9335 9344 9346 9353-9354 9356 9367-9368 9400-9401 9403 9408 9413 9418 9429 9433-9434 9436 9439-9440 9443-9445 9449 9454 9465 9467-9469 9471 9474 9505 9605 9607 9611 9613 9632 9634 9644 9646 9736 9792 9796 9807 9812 9828 9830 9834 9848 9850-9851 9860 9891 9920-9921 9939 9943-9944 9947-9948 9953 9971 9978 9982 9986 9990 10017 10024-10025 10106 10113-10114 10118 10123 10180 10182 10200 10247 10254 10265 10287 10289 10292 10296 10328-10329 10332 10339 10344 10346 10348 10355 10359 10378-10379 10384 10388 10390-10391 10397-10399 10404 10410 10425 10435 10437 10439-10442 10444-10445 10451 10456 10461 10465 10475 10481 10501 10514 10518-10519 10528 10533 10536 10556 10562 10570 10631 10661 10685 10706 10730 10742 10745 10759 10771 10773 10776 10788 10796 10800-10801 10816 10820 10835 10843 10845-10847 10852 10862 10865 10868 10870 10880 10930 10932 10936 10948 10951 10966 10970 10972 10984 10987 10997-10998 11001 11010 11019 11029 11042 11048 11051 11055 11061-11062 11071 11090 11107 11110 11112 11119 11168 11170 11172 11175 11178 11183 11186 11195-11196 11235 11256 11259 11268 11271 11273 11279 11287 11312 11322 11328 11346 11351 11365 11376 11412-11413 11436 11438 11443 11475 11502 11513 11591 11595-11596 11777 11788 11806 11810 11826 11831 11872-11873 11881 11906 11932 12400-12401 12480 12546 12551 16894 17214 17237 17239 17241 17329 17344 17500 17502 17511 17513 17520 17672 17727 17741 17747-17748 17816 17821 17856 17997 17999 18007 18012 18017-18018 18022 18032 18070-18071 18303 18383 18387 18405 18518 18524 18535 18794 18839 19033-19034 19049 19097 19121 19390 19408 19424 19456 19673 19675-19676 19689-19690 19733 19735 19841 19983 19993 19998 20005 20008 21845 21847 21876 21879 21887 21977 21980 22364-22365 22397 22717 23043 23046 23051 23060 23144 23186-23187 23197 23201-23202 23210 25565 25582 25587 25843 25852 25926 25936 25943 25945 25958 25974 25981-25982 25988-25990 26005 26015 26029 26035 26046 26051 26064 26070 26077 26089 26106 26110 26165 26174 26178 26200 26207 26227 26239 26241 26289 26294 26306 26319 26324 26326 26335 26338 26348 26351 26366 26372-26373 26375 26382 26385-26386 26388 26390 26393 26396 26398 26402 26410-26411 26414-26415 26422 26424 26430 26433 26450-26451 26460 26470 26486-26488 26497 26510 26512 26515 26519 26530 26536 26540 26547 26561 26573 26576 26595 26600 26614 26621 26947 26954 26956 26966 26975-26976 26979 27000-27001 27027 27038 27043 27056-27058 27061 27071 27081 27085-27086 27088 27092 27094 27096 27107 27109 27111-27112 27117 27123 27125-27127 27130 27199 27222 27224-27225 27230 27237 27239 27244-27245 27248 27250 27258-27259 27293 27299 27310 27332 27339-27340 27345 27347 27356 27389 27392 27395 27398 27414 27423-27425 27434 27437-27438 27454 27464 27466 27469 27477 27482 27484-27486 27489 27495 27501 27541 27543 27565-27566 27576 27583 27586 27588 27595 27602 27612-27613 27618 27623 27625 27628 27630 27636 27640-27641 27643 27659 27674 27686 27699 27705 27725 27735 27738 27740 27742 27752 27756-27757 27784 27821 27827 27830 27857 27862 27864 27866 27877 27880 27882 27899-27900 27936 27942 27960 27973 27988 28088 28110 28127 28148 28150 28156 28164-28165 28189 28192 28196 28207 28220 28224-28226 28231 28247 28250 28252-28253 28263 28273 28281-28282 28299-28300 28307 28315 28323 28330 28336 28348-28349 28361 28363 28368 28371 28375 28379 28390-28392 28396 28400-28401 28403 28405-28406 28409-28412 28414 28416-28417 28421 28435 28438 28447 28449 28468 28474 28492 28501 28512 28514 28516 28520 28538 28544 28547-28549 28552 28554 28557 28563 28571 28585 28587 28597-28599 28606 28609 28635 28640 28650 28653 28660 28664 30045 30064 31355 31366 31397 31419 31426 31443 31450 31461 31463 31465-31467 31473 31545 31624 31633 31640 31647 31653 31658-31659 31677-31678 31695 31712 31715 31717 31727 31734 31736 31742 32408 32414-32415 32431 32444 32447 32462 32484 32490 32492 36715 36733 36763 36782 36788 36792 36807 36812 40959 45051 49019 49106 49128https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/466/2879?format=asciidefaultJ/MNRAS/466/2879/table1All the BPT-selected AGN candidates and additional AGN candidates selected by the HeII methodSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSDSSSDSS ObjIdmeta.idcharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainzRedshiftsrc.redshiftdoubleMassMasssolMassphys.massdoubleu-r? SDSS u-r colour indexmagphot.color;em.opt.U;em.opt.RdoublenullableBPT-AGN[0/1] BPT-selected AGN candidates ?meta.codeintHeII-AGN[0/1] HeII-selected AGN candidates ?meta.codeintHeII-BPT-AGN[0/1] AGN candidates selected by both methods ?meta.codeintHeII-only[0/1] HeII-only AGN candidates ?meta.codeintBAD[0/1] 1 when HeII spectra considered as unreliablemeta.codeintSloanDisplay the online SDSS data for this galaxymeta.ref.urlchar