J/ApJ/896/L43ivo://CDS.VizieR/J/ApJ/896/L43doi:10.26093/cds/vizier.18969043CDSRiess A.G.Yuan W.Casertano S.Macri L.M.Scolnic D.2022-03-21T07:02:57Z2021-12-03T08:28:49ZCDS support team

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

cds-question@unistra.frhst-photometryvariable-starsgalaxiesinfrared-photometryvisible-astronomyThe accuracy of the Hubble constant measured with extragalactic Cepheids depends on robust photometry and background estimation in the presence of stellar crowding. The conventional approach accounts for crowding by sampling backgrounds near Cepheids and assuming that they match those at their positions. We show a direct consequence of crowding by unresolved sources at Cepheid sites is a reduction in the fractional amplitudes of their light curves. We use a simple analytical expression to infer crowding directly from the light curve amplitudes of >200 Cepheids in three Type Ia supernovae hosts and NGC4258 as observed by Hubble Space Telescope-the first near-infrared amplitudes measured beyond the Magellanic Clouds. Where local crowding is minimal, we find near-infrared amplitudes match Milky Way Cepheids at the same periods. At greater stellar densities we find that the empirically measured amplitudes match the values predicted (with no free parameters) from crowding assessed in the conventional way from local regions, confirming their accuracy for estimating the background at the Cepheid locations. Extragalactic Cepheid amplitudes would need to be ~20% smaller than measured to indicate additional, unrecognized crowding as a primary source of the present discrepancy in H0. Rather, we find the amplitude data constrains a systematic mis-estimate of Cepheid backgrounds to be 0.029R+/-0.037mag, more than 5x smaller than the size of the present ~0.2mag tension in H0. We conclude that systematic errors in Cepheid backgrounds do not provide a plausible resolution to the Hubble tension.2020ApJ...896L..43Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/896/L43CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/hst : HST Archived Exposures Catalog (STScI, 2007)J/ApJ/699/539 : Cepheids in SN-Ia host galaxies (Riess+, 2009)J/ApJS/193/12 : JHK photometry of Northern Galactic Cepheids (Monson+, 2011)J/ApJ/730/119 : HST/WFC3 observations of Cepheids in SN Ia hosts (Riess+, 2011)J/ApJ/830/10 : HST obs. of Cepheids in SNIa host gal. (Hoffmann+, 2016)J/ApJ/826/56 : HST/WFC3 obs. of Cepheids in SN Ia host gal. (Riess+, 2016)J/ApJ/876/85 : HST observations for LMC Cepheids (Riess+, 2019)J/ApJ/889/5 : HST obs. of Mira variables in NGC1559 (Huang+, 2020)http://archive.stsci.edu/hst/ : MAST HST archivehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/896/L43https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/896/L43http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/896/L43https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/896/L43https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/896/L43http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/896/L43GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/896/L43/table1 (Amplitude data for Milky Way Cepheids)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/896/L43/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/896/L43/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/896/L43/table1?GETtext/xml+votable180.050000true78.163446442.83178220.005555555555555556Cone search capability for table J/ApJ/896/L43/table3 (Amplitude and crowding data for extragalactic Cepheid)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/896/L43/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/896/L43/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/896/L43/table3?GETtext/xml+votable180.050000true6/1426 1431 1445 1467 1829 1836 3361 3600 3616 10977 10979 12968 13310 14205 14262 14409 14431 14625 14690 14698 14718 15461 15618 23622 24372 28717 29095 30222 30258 37223 37235 37303 37340 37757 37867 37888 37917 37929-37931 38022-38023 38049 39244 39410 39766 39771 39790 39892 39908 39933 41667 41673 41813 42185 42378https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/896/L43?format=asciiOpticalInfrareddefaultJ/ApJ/896/L43/table1Amplitude data for Milky Way CepheidsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCepheid name (1)meta.id;meta.maincharPer[10.15/69.16] Perioddtime.periodfloatVamp[0.6/1.34] Amplitude, V band magnitudemagphot.mag;src.var.amplitude;em.opt.VfloatHamp[0.17/0.55] Amplitude, H band magnitudemagphot.mag;src.var.amplitudefloatM11Display data from Monson+, 2011, J/ApJS/193/12meta.ref.urlintnullableSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/ApJ/896/L43/table3Amplitude and crowding data for extragalactic CepheidSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDCepheid Identifiermeta.id;meta.maincharhostGalaxy host (n1559, n2525, n5643 or "n4258i" or "n4258o") (1)meta.id.parentcharlogP[1/2.1] Log Periodlog(d)time.periodfloatdmV[-0.11/0.19] Crowding correction, V band magnitudemagphot.mag;arith.difffloatdmH[0.016/2.03] Crowding correction, H band magnitudemagphot.mag;arith.difffloatVamp[0.26/1.22] Amplitude, V band magnitudemagphot.mag;src.var.amplitude;em.opt.VfloatHamp[-0.21/0.51] Amplitude, H band magnitudemagphot.mag;src.var.amplitudefloatsigma[0.06/0.18] Combined error (2)magstat.error;phot.magfloat_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.mainnullable_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainnullable