J/ApJ/737/45ivo://CDS.VizieR/J/ApJ/737/45doi:10.26093/cds/vizier.17370045CDSOfek E.O.Frail D.A.2013-02-23T22:26:08Z2013-02-08T09:21:05ZCDS support team

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

cds-question@unistra.frradio-sourcesradio-continuum-emissionsurveysWe augment the two widest/deepest 1.4GHz radio surveys, the NRAO VLA Sky Survey (NVSS) and the Faint Images of the Radio Sky at Twenty centimeters (FIRST), with the mean epoch in which each source was observed. We use these catalogs to search for unresolved sources that vary between the FIRST and NVSS epochs. We find 43 variable sources (0.1% of the sources) that vary by more than 4{sigma}, and we construct the mean structure function of these objects. This enables us to explore radio variability on timescales between several months and about five years. We find that, on these timescales, the mean structure function of the variable sources is consistent with a flat structure function. A plausible explanation to these observations is that a large fraction of the variability at 1.4GHz is induced by scintillations in the interstellar medium, rather than by intrinsic variability. Finally, for a subsample of the variables for which the redshift is available, we do not find strong evidence for a correlation between the variability amplitude and the source redshift.2011ApJ...737...45Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/737/45CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVIII/90 : The FIRST Survey Catalog, Version 12Feb16 (Becker+ 2012)II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)I/284 : The USNO-B1.0 Catalog (Monet+ 2003)IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)VIII/26 : Low-Frequency Variable Radio Sources Monitoring (Mitchell+, 1994)J/AJ/127/2565 : Faint FIRST variable radio sources (de Vries+, 2004)J/MNRAS/315/839 : Compact variable radio sources at 151MHz. I. (Minns+, 2000)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/737/45https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/737/45http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/737/45https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/737/45https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/737/45http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/737/45GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/737/45/table2 (Observing Times of FIRST Sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/737/45/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/737/45/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/737/45/table2?GETtext/xml+votable180.050000true354.74904611-11.398828060.005555555555555556Cone search capability for table J/ApJ/737/45/table3 (Variable sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/737/45/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/737/45/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/737/45/table3?GETtext/xml+votable180.050000true229.95525-5.908280.005555555555555556Cone search capability for table J/ApJ/737/45/table1 (Observing times of NVSS sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/737/45/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/737/45/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/737/45/table1?GETtext/xml+votable180.050000true262.460375-40.430806110.0055555555555555560/0 1 2 3 1/17 18 19 21 22 23 25 26 27 29 30 31 2/65 66 67 81 82 83 97 98 99 113 114 115 139 141 142 143 157 158 159 173 174 175 189 190 191 3/257 258 259 321 322 323 385 386 387 449 450 451 535 541 542 543 551 561 562 563 605 606 607 621 622 623 625 626 627 663 669 670 671 685 686 687 689 690 691 727 733 734 735 747 749 750 751 753 754 755 4/1025 1026 1027 1281 1282 1283 1537 1538 1539 1793 1794 1795 2157 2158 2159 2161 2162 2163 2221 2222 2223 2241 2242 2243 2397 2398 2399 2413 2414 2415 2417 2418 2419 2461 2462 2463 2477 2478 2479 2481 2482 2483 2497 2498 2499 2669 2670 2671 2673 2674 2675 2717 2718 2719 2733 2734 2735 2737 2738 2739 2753 2754 2755 2925 2926 2927 2929 2930 2931 2973 2974 2975 2993 2994 2995 3009 3010 3011 5/4097 4098 4099 5121 5122 5123 6145 6146 6147 7169 7170 7171 8541 8542 8543 8557 8558 8559 8605 8606 8607 8621 8622 8623 8625 8626 8627 8641 8642 8643 8797 8798 8799 8807 8813 8814 8815 8861 8862 8863 8877 8878 8879 8881 8882 8883 8961 8962 8963 9565 9566 9567 9581 9582 9583 9585 9586 9587 9629 9630 9631 9645 9646 9647 9649 9650 9651 9665 9666 9667 9821 9822 9823 9837 9838 9839 9841 9842 9843 9885 9886 9887 9901 9902 9903 9905 9906 9907 9921 9922 9923 9985 9986 9987 10589 10590 10591 10605 10606 10607 10653 10654 10655 10669 10670 10671 10673 10674 10675 10689 10690 10691 10845 10846 10847 10861 10862 10863 10865 10866 10867 10903 10909 10910 10911 10925 10926 10927 10929 10930 10931 10945 10946 10947 11009 11010 11011 11607 11613 11614 11615 11629 11630 11631 11671 11677 11678 11679 11693 11694 11695 11697 11698 11699 11713 11714 11715 11869 11870 11871 11885 11886 11887 11889 11890 11891 11933 11934 11935 11949 11950 11951 11969 11970 11971 12033 12034 12035 6/16385 16386 16387 20481 20482 20483 24577 24578 24579 28673 28674 28675 34141 34142 34143 34157 34158 34159 34161 34162 34163 34205 34206 34207 34221 34222 34223 34225 34226 34227 34397 34398 34399 34413 34414 34415 34417 34418 34419 34461 34462 34463 34477 34478 34479 34481 34482 34483 34497 34498 34499 34561 34562 34563 35165 35166 35167 35181 35182 35183 35185 35186 35187 35245 35246 35247 35249 35250 35251 35421 35422 35423 35435 35437 35438 35439 35441 35442 35443 35485 35486 35487 35499 35501 35502 35503 35505 35506 35507 35521 35522 35523 35841 35842 35843 38237 38238 38239 38253 38254 38255 38257 38258 38259 38301 38302 38303 38317 38318 38319 38321 38322 38323 38337 38338 38339 38493 38494 38495 38509 38510 38511 38513 38514 38515 38557 38558 38559 38573 38574 38575 38577 38578 38579 38593 38594 38595 38657 38658 38659 39261 39262 39263 39277 39278 39279 39281 39282 39283 39325 39326 39327 39341 39342 39343 39345 39346 39347 39361 39362 39363 39517 39518 39519 39533 39534 39535 39537 39538 39539 39581 39582 39583 39595 39597 39598 39599 39601 39602 39603 39617 39618 39619 39681 39682 39683 39937 39938 39939 42333 42334 42335 42347 42349 42350 42351 42353 42354 42355 42391 42397 42398 42399 42411 42413 42414 42415 42417 42418 42419 42589 42590 42591 42605 42606 42607 42609 42610 42611 42653 42654 42655 42669 42670 42671 42673 42674 42675 42689 42690 42691 42753 42754 42755 43357 43358 43359 43373 43374 43375 43377 43378 43379 43421 43422 43423 43437 43438 43439 43441 43442 43443 43457 43458 43459 43629 43630 43631 43633 43634 43635 43675 43677 43678 43679 43693 43694 43695 43697 43698 43699 43713 43714 43715 43777 43778 43779 44033 44034 44035 46445 46446 46447 46449 46450 46451 46493 46494 46495 46509 46510 46511 46513 46514 46515 46701 46702 46703 46705 46706 46707 46749 46750 46751 46765 46766 46767 46769 46770 46771 46785 46786 46787 46849 46850 46851 47453 47454 47455 47469 47470 47471 47473 47474 47475 47517 47518 47519 47533 47534 47535 47537 47538 47539 47553 47554 47555 47709 47710 47711 47725 47726 47727 47729 47730 47731 47773 47774 47775 47789 47790 47791 47793 47794 47795 47873 47874 47875 48129 48130 481319.276497240453405e-25 4.653515163505597e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/737/45?format=asciiRadiodefaultJ/ApJ/737/45/table2Observing Times of FIRST SourcesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainindexedDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainindexedSp1.4GHz peak fluxmJyphot.flux.density;em.radio.750-1500MHzdoublee_SpThe rms in PFluxmJystat.error;src.spTypefloatNobsNumber of observationsmeta.numberintt? Mean Julian day of the observation (1)dtime.epoch;obs;stat.meandoublenullabledt? Time span of the observations {delta}t (1)dtime.intervaldoublenullableFIRSTCross-match with FIRST (Cat. VIII/90) within 1"meta.ref.urlcharJ/ApJ/737/45/table3Variable sourcesS2NVSS peak specific fluxmJyphot.flux.density;em.radio.750-1500MHzfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainRem[a-h ] Comment on individual source (1)meta.notecharS1FIRST peak specific fluxmJyphot.flux.density;em.radio.750-1500MHzfloate_S1The rms in S1mJystat.errorfloate_S2The rms in S2mJystat.errorfloatf_S2[C] C: complex source in NVSS (2)meta.codecharDtTime between the FIRST and NVSS observationdtime.intervalfloatB2mag? USNO-B1 B_2_-band magnitude (3)magphot.mag;em.opt.BfloatnullableR2mag? USNO-B1 R_2_-band magnitude (3)magphot.mag;em.opt.RfloatnullableJmag? 2MASS J-band magnitude (3)magphot.mag;em.IR.JfloatnullableHmag? 2MASS H-band magnitude (3)magphot.mag;em.IR.HfloatnullableKmag? 2MASS K-band magnitude (3)magphot.mag;em.IR.KfloatnullablerX? Distance from ROSAT source (3)arcsecpos;arith.difffloatnullablegmag? SDSS g-band magnitude (3)magphot.mag;em.opt.Bfloatnullablermag? SDSS r-band magnitude (3)magphot.mag;em.opt.Rfloatnullablezsp? SDSS spectroscopic redshiftsrc.redshiftfloatnullablezph? SDSS photometric redshift (4)src.redshiftfloatnullableOCatCross-match within 3" with USNO-B1 and SDSS-DR7meta.ref.urlintnullableICatCross-match within 3" with 2MASS catalogsmeta.ref.urlintnullableobsLink to NVSS and FIRST observing times (tables 1 and 2)meta.ref.urlcharJ/ApJ/737/45/table1Observing times of NVSS sourcesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainindexedDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainindexedSp1.4GHz peak fluxmJyphot.flux.density;em.radio.750-1500MHzdoublee_SpThe rms in PFluxmJystat.error;src.spTypefloatNobsNumber of observationsmeta.numberintt? Mean Julian day of the observation (1)dtime.epoch;obs;stat.meandoublenullabledtTime span of the observationsdtime.intervaldoublenullableNVSSCross-match with NVSS (Cat. VIII/65) within 1"meta.ref.urlchar