J/MNRAS/474/4937ivo://CDS.VizieR/J/MNRAS/474/4937doi:10.26093/cds/vizier.74744937CDSChhetri R.Morgan J.Ekers R.D.Macquart J.-P.Sadler E.M.,Giroletti M.Callingham J.R.Tingay S.J.2024-08-18T20:17:37Z2021-04-19T12:45:53ZCDS support team

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

cds-question@unistra.frradio-sourcesradio-galaxiesinterferometryWe report the first astrophysical application of the technique of wide-field interplanetary scintillation (IPS) with the Murchison Widefield Array (MWA). This powerful technique allows us to identify and measure sub-arcsecond compact components in low-frequency radio sources across large areas of sky without the need for long-baseline interferometry or ionospheric calibration. We present the results of a 5-min observation of a 30x30deg^2^ MWA field at 162MHz with 0.5s time resolution. Of the 2550 continuum sources detected in this field, 302 (12 per cent) show rapid fluctuations caused by IPS. We find that at least 32 per cent of bright low-frequency radio sources contain a sub-arcsecond compact component that contributes over 40 per cent of the total flux density. Perhaps surprisingly, peaked-spectrum radio sources are the dominant population among the strongly scintillating, low-frequency sources in our sample. While gamma-ray active galactic nuclei are generally compact, flat-spectrum radio sources at higher frequencies (162MHz), the properties of many of the Fermi blazars in our field are consistent with a compact component embedded within more extended low-frequency emission. The detection of a known pulsar in our field shows that the wide-field IPS technique is at the threshold of sensitivity needed to detect new pulsars using image plane analysis, and scaling the current MWA sensitivity to that expected for SKA-low implies that large IPS-based pulsar searches will be feasible with SKA. Calibration strategies for the SKA require a better knowledge of the space density of compact sources at low radio frequencies, which IPS observations can now provide.2018MNRAS.474.4937Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/474/4937CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/473/2965 : Interplanetary scintillation at 79 and 158MHz (Morgan+ 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/474/4937https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/474/4937http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/474/4937https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/474/4937https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/474/4937http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/474/4937GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/474/4937/table1 (MWA IPS II catalogue)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/474/4937/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/474/4937/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/474/4937/table1?GETtext/xml+votable180.050000true0.0159583-28.4046750.0055555555555555564/1031 1037 1042-1043 1045-1046 1048-1050 1052-1053 1076 1098 2238 5/4113-4115 4117 4119-4121 4123 4144-4145 4153 4157-4160 4162 4164 4166-4167 4176-4177 4179 4188-4189 4191 4204-4206 4216-4218 4220-4222 4245 4289-4291 4293-4295 4308-4310 4312 4316-4317 4352 4358 4360-4361 4363-4364 4366 4378 4384-4386 4390-4391 4401 4408 4481 4483 4488-4489 8884 8886-8887 8893 8895 8911 8920 8922-8923 8927-8928 8932 8934-8936 8939-8940 8942-8945 8947-8949 8958 9123 9128 9130-9131 9133 6/16404-16405 16407 16410-16412 16415 16427 16433-16435 16438 16441 16445-16449 16451 16464-16466 16472 16474-16475 16488 16490 16512 16514 16518 16523-16524 16526 16528 16530-16534 16536-16537 16539-16540 16542-16543 16561 16565 16567 16572 16584 16586 16589-16591 16608-16609 16611 16617 16619 16621-16622 16624-16626 16644-16645 16647 16653-16655 16661-16663 16712-16714 16760 16762-16763 16828-16829 16831 16876 16878-16879 16892-16894 16900-16901 16916-16918 16961 16963 16965-16967 16972 16975-16976 16978-16979 16985-16986 16988-16989 16991 16993 16998-16999 17005 17009 17011-17012 17014-17015 17023 17110 17141 17153-17155 17168-17170 17184-17185 17188-17189 17192 17197 17199 17201-17204 17206-17207 17209-17213 17215 17244-17245 17247 17252 17254-17257 17259 17261 17263 17273-17276 17279 17283 17286 17293 17297 17305-17306 17309 17311 17316 17333 17346-17349 17351-17352 17362 17364-17365 17370-17371 17375 17380 17389 17401-17402 17407 17412-17414 17416-17418 17420 17422-17424 17426-17427 17430 17436 17439 17449-17451 17460 17462-17463 17468-17470 17472 17475 17480 17485-17488 17496 17504-17505 17507 17509-17511 17516 17518-17520 17530 17532 17548-17549 17551-17553 17555-17558 17584 17586 17588 17590-17593 17600-17602 17609 17612 17614 17617-17620 17624 17627 17629 17631 17638-17639 17641-17642 17644 17657-17658 17662 17793 17802-17803 17825 17920 17922-17923 17928-17930 17936-17937 17939-17940 17943-17945 17950 17960 17963 17965-17966 17969-17972 17976 17979 17985-17986 17992-17993 17996 18000 18004 18016-18017 18048 18057 18063 18065-18066 18089 18752 18769 35259 35304 35306 35314 35322 35439 35447 35449 35453 35455 35515 35517 35528 35533 35540 35542 35553-35555 35557-35559 35561-35562 35565-35568 35570-35571 35576-35577 35579 35598 35608-35609 35612-35614 35617 35619 35621-35622 35625-35627 35629-35631 35634-35637 35639 35641 35651 35656 35659-35662 35666 35668 35673 35684 35686 35696 35698-35700 35702 35706-35707 35716-35717 35719 35721-35724 35726 35732 35734-35735 35749-35752 35754-35755 35764-35766 35784 35786-35787 35800-35801 35803-35804 35806-35807 35824 35826 35828 35830-35831 35836-35837 35839 36362 36367 36378 36384 36391-36392 36394 36396-36397 36402 36408 36410 36480-36482 36484-36485 36487-36490 36497-36498 36503-36504 36507-36509 36516-36517 36519 36528-36529 36537-36540 36543 36578 36587-36588 36591 36603 46541https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/474/4937?format=asciiRadiodefaultJ/MNRAS/474/4937/table1MWA IPS II cataloguerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameGLEAM Source name from GLEAM catalogue, JHHMMSS-DDMMSSmeta.id;meta.maincharRAJ2000Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainS162Estimated peak flux density at 162MHz from GLEAMJy/beamphot.flux.density;em.radio.100-200MHzfloate_S162Uncertainty in 162MHz peak flux densityJy/beamstat.errorfloatalphaSpectral index from GLEAM cataloguespect.indexfloatn_alphaFlag on alpha (1)meta.notechare_alpha? Uncertainty in spectral indexstat.error;pos.eq.rafloatnullablenNVSSNumber NVSS of counterparts within 60arcsecond of GLEAM positionmeta.numberintS1400? Integrated flux density from NVSS, only when single counterpart listed in nNVSSJyphot.flux.density;em.radio.750-1500MHzfloatnullableElongSolar Elongation on date of observationdegpos.ecliptic.lonNormSNRNormalised signal to noise ratiostat.snrfloatl_SIUpper limit flag on SImeta.code.errorcharSIScintillation indexsrc.var.indexfloate_SI? Uncertainty in SIstat.errorfloatnullablel_NSIUpper limit flag on NSImeta.code.errorcharNSINormalised Scintillation Indexsrc.var.indexfloate_NSI? Uncertainty in NSIstat.errorfloatnullableFlag[AFP ] Flag (2)meta.code.errorcharSEDName of the file with SED in subdirectory sedmeta.id;meta.filechar