J/ApJ/795/63ivo://CDS.VizieR/J/ApJ/795/63doi:10.26093/cds/vizier.17950063CDSFarnes J.S.O'Sullivan S.P.Corrigan M.E.Gaensler B.M.2017-12-04T05:48:38Z2017-05-23T14:09:26ZCDS support team

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

cds-question@unistra.frquasarsgalaxy-rotationradio-galaxiesmagnetic-fieldspolarimetryredshiftedStrong singly ionized magnesium (Mg II) absorption lines in quasar spectra typically serve as a proxy for intervening galaxies along the line of sight. Previous studies have found a correlation between the number of these Mg II absorbers and the Faraday rotation measure (RM) at ~5 GHz. We cross-match a sample of 35752 optically identified non-intrinsic Mg II absorption systems with 25649 polarized background radio sources for which we have measurements of both the spectral index and RM at 1.4 GHz. We use the spectral index to split the resulting sample of 599 sources into flat-spectrum and steep-spectrum subsamples. We find that our flat-spectrum sample shows significant (~3.5{sigma}) evidence for a correlation between Mg II absorption and RM at 1.4 GHz, while our steep-spectrum sample shows no such correlation. We argue that such an effect cannot be explained by either luminosity or other observational effects, by evolution in another confounding variable, by wavelength-dependent polarization structure in an active galactic nucleus, by the Galactic foreground, by cosmological expansion, or by partial coverage models. We conclude that our data are most consistent with intervenors directly contributing to the Faraday rotation along the line of sight, and that the intervening systems must therefore have coherent magnetic fields of substantial strength (B{bar}=1.8+/-0.4{mu}G). Nevertheless, the weak nature of the correlation will require future high-resolution and broadband radio observations in order to place it on a much firmer statistical footing.2014ApJ...795...63Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/795/63CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)J/ApJS/45/97 : Extragal. Radio Sources Faraday RotationJ/MNRAS/376/371 : Polarisation of flat-spectrum radio sources (Jackson+, 2007)J/ApJ/702/1230 : Rotation measure image of the sky (Taylor+, 2009)J/MNRAS/409/821 : Radio sources with ultrahigh polarization (Shi+, 2010)J/ApJS/212/15 : Polarized NVSS sources SEDs (Farnes+, 2014)J/MNRAS/442/3329 : Rotation measures of 2642 quasars (Xu+, 2014)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/795/63https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/795/63http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/795/63https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/795/63https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/795/63http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/795/63GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/795/63/table2 (Details of the Main Sample, Listed in Order of NVSS Right Ascension)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/795/63/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/795/63/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/795/63/table2?GETtext/xml+votable180.050000true0.93825-11.13905560.0055555555555555566/546 712 4106 4108 4155 4167 4195 4223 4240 4263 4269 4280 4283 4284 4285 4322 4328 4333 4341 4345 4352 4358 4405 4407 4410 4436 4441 4446 4448 4473 4475 4476 4524 4525 4536 4537 4572 4575 4587 4594 4628 4674 4695 4696 4698 4708 4710 4758 4759 4809 4812 4815 4848 4850 4852 4862 4866 4885 4892 4918 4919 4943 4976 4985 4989 4992 5001 5009 5125 5132 5135 5145 5147 5154 5172 5185 5190 5200 5242 5255 5258 5259 5264 5278 5302 5305 5331 5334 5353 5397 5430 5445 5448 5466 5471 5472 5482 5510 5513 5528 5540 5546 5570 5574 5579 5585 5588 5657 5673 5678 5689 5693 5696 5722 5732 5743 5749 5771 5781 5800 5807 5817 5833 5847 5848 5864 5885 5912 5918 5919 5928 5951 5988 6033 6114 6120 6121 6233 6268 6412 6433 6472 6490 6498 6511 6543 6548 6555 6566 6597 6608 6620 6632 6644 6646 6928 7195 7197 7200 7240 7343 7346 7364 7390 7392 7393 7396 7426 7446 7458 7464 7468 7472 7525 7587 8199 8214 8234 8255 8258 8283 8299 8337 8342 8343 8345 8349 8353 8373 8378 8413 8415 8424 8425 8452 8466 8468 8510 8519 8528 8536 8539 8548 8580 8585 8640 8660 8669 8687 8704 8709 8720 8773 8774 8780 8793 8799 8812 8830 8858 8889 8915 8919 8921 8939 8948 8985 8991 8994 9002 9021 9073 9123 9136 9138 9140 9161 9164 9170 9220 9241 9252 9264 9266 9272 9273 9355 9366 9394 9402 9437 9447 9452 9456 9467 9512 9605 9636 9637 9739 9778 9796 9799 9812 9863 9865 9882 9903 9929 9949 9978 9999 10116 10288 10314 10318 10330 10352 10353 10372 10374 10411 10417 10422 10432 10466 10529 10557 10563 10587 10628 10633 10634 10700 10702 10705 10744 10755 10758 10761 10762 10767 10780 10786 10788 10826 10849 10851 10863 10875 10878 10881 10898 10901 10910 10924 10925 10932 10961 10964 10969 10976 10977 10979 11005 11050 11087 11094 11099 11117 11118 11137 11147 11165 11167 11171 11191 11197 11207 11241 11260 11274 11276 11290 11292 11297 11299 11311 11385 11392 11436 11459 11474 11480 11491 11508 11572 11783 11785 11787 11813 11854 11919 11924 11937 11941 11948 11954 11956 12547 13317 17213 17238 17316 17492 17495 17522 17564 17750 17758 17761 17763 17904 18004 18022 18027 18067 18069 18300 18402 18416 18514 18517 18548 18627 18774 18881 19089 19090 19091 19326 19389 19426 19670 19673 19685 19757 19776 19940 20001 21844 23045 23210 25841 25844 25915 25923 25950 25956 25964 25971 26007 26011 26035 26036 26044 26090 26095 26097 26106 26185 26198 26220 26250 26301 26340 26374 26432 26499 26525 26529 26540 26541 26559 26564 26571 26878 26982 26983 26993 27002 27083 27100 27115 27117 27241 27249 27291 27301 27310 27315 27322 27359 27382 27413 27448 27453 27455 27465 27479 27486 27509 27514 27516 27520 27549 27583 27589 27657 27660 27671 27700 27719 27739 27749 27751 27796 27803 27805 27821 27845 27857 27901 27916 27955 27956 27964 27965 27972 27981 27999 28030 28035 28041 28042 28045 28059 28070 28072 28077 28097 28099 28134 28135 28167 28216 28276 28292 28293 28294 28315 28339 28351 28383 28436 28438 28439 28446 28460 28463 28471 28474 28479 28528 28529 28530 28536 28544 28548 28564 28571 28575 28577 28581 28666 28671 31324 31333 31353 31357 31391 31419 31426 31439 31451 31454 31458 31463 31535 31663 31686 31718 31735 32397 32480 32486 32674https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/795/63?format=asciiRadioOpticaldefaultJ/ApJ/795/63/table2Details of the Main Sample, Listed in Order of NVSS Right AscensionSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNumber[1/599] Source numbermeta.id;meta.mainintRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainalpha? Total intensity spectral indexspect.indexfloatnullableDalpha? Total intensity spectral index differencespect.indexfloatnullableChi2? {Chi}^2^ valuestat.fit.chi2floatnullableSample[FS-] Source subsample (1)meta.id;meta.datasetcharNMgII[0/5] Number of Mg II absorbersmeta.numberintRMFaraday rotation measurerad.m**-2phys.polarization.rotMeasurefloatDRMFaraday rotation measure differencerad.m**-2phys.polarization.rotMeasure;arith.difffloatPiFractional polarization%phys.polarizationfloatDPiFractional polarization difference%phys.polarizationfloatbeta? Polarization spectral indexspect.indexfloatnullableDbeta? Polarization spectral index differencespect.indexfloatnullablezRedshift for the polarized background radio sourcessrc.redshiftdoubleDzRedshift differencesrc.redshift;arith.difffloatCatsDisplay data from Farnes et al. (2014, Cat. J/ApJS/212/15) and Taylor et al. (2009, Cat. J/ApJ/702/1230meta.ref.urlchar