J/ApJS/245/14ivo://CDS.VizieR/J/ApJS/245/14doi:10.26093/cds/vizier.22450014CDSElmegreen B.G.Elmegreen D.M.2020-09-29T13:41:37Z2020-05-13T13:26:26ZCDS support team

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

cds-question@unistra.frgalaxiesinfrared-photometrytwo-color-diagramsinterstellar-mediumSpitzer Space Telescope observations of 15 spiral galaxies show numerous dense cores at 8{mu}m that are revealed primarily in unsharp mask images. The cores are generally invisible in optical bands because of extinction, and they are also indistinct at 8{mu}m alone because of contamination by more widespread diffuse emission. Several hundred core positions, magnitudes, and colors from the four InfraRed Array Camera bands are measured and tabulated for each galaxy. The larger galaxies, which tend to have longer and more regular spiral arms, often have their infrared cores aligned along these arms, with additional cores in spiral arm spurs. Galaxies without regular spirals have their cores in more irregular spiral-like filaments, with typically only one or two cores per filament. Nearly every elongated emission feature has 8{mu}m cores strung out along its length. The occurrence of dense cores in long and thin filaments is reminiscent of filamentary star formation in the solar neighborhood, although on a scale 100 times larger in galaxies. The cores most likely form by gravitational instabilities and cloud agglomeration in the filaments. The simultaneous occurrence of several cores with regular spacings in some spiral arms suggests that in these cases, all of the cores formed at about the same time and the corresponding filaments are young. Total star formation rates for the galaxies correlate with the total embedded stellar masses in the cores with an average ratio corresponding to a possible age between 0.2 and 2Myr. This suggests that the identified cores are the earliest phase for most star formation.2019ApJS..245...14Ehttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/245/14CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/642/158 : IRAC flux densities in IC2163 and NGC2207 (Elmegreen+, 2006)J/ApJS/173/538 : XUV-Disk galaxies in the Local Universe (Thilker+, 2007)J/ApJ/669/493 : Spitzer/Chandra YSOs in Serpens cloud core (Winston+, 2007)J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)J/ApJ/701/1965 : Radial dust properties of SINGS galaxies (Munoz-Mateos+, 2009)J/ApJS/190/233 : Spectroscopy & abundances of SINGS galaxies (Moustakas+, 2010)J/ApJ/745/95 : Herschel FIR & submm photom. of KINGFISH sample (Dale+, 2012)J/ApJ/757/52 : UV and IR observations for SINGS galaxies. I. (Mao+, 2012)J/ApJ/767/36 : APEX observations of HOPS protostars (Stutz+, 2013)J/A+A/552/A19 : Radio-farIR correlation in NGC 6946 (Tabatabaei+, 2013)J/A+A/576/A33 : KINGFISH galaxy sample radial profile SED (Hunt+, 2015)J/A+A/616/A78 : Dust extinction map of the Nessie filament (Mattern+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/245/14https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/245/14http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/245/14https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/245/14https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/245/14http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/245/14GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/245/14/table2 (8um cores in the galaxy sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/245/14/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/245/14/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/245/14/table2?GETtext/xml+votable180.050000true24.249833315.77063890.005555555555555556Cone search capability for table J/ApJS/245/14/table1 (Galaxies)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/245/14/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/245/14/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/245/14/table1?GETtext/xml+votable180.050000true24.1740515.78346110.0055555555555555566/5492 5715 7741 7743 10856 10901 11026 11027 15592 15593 16441 18398 27514 27861 27914 28123 33958 438812.0616683193919197e-20 6.185923063528282e-20https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/245/14?format=asciiInfrareddefaultJ/ApJS/245/14/table28um cores in the galaxy samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNGCGalaxy identifiermeta.id.parentintRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.main3.6mag[10.7/25.6] Spitzer/IRAC 3.6um band magnitudemagphot.mag;em.IR.3-4umfloate_3.6mag[0.04/55]? Uncertainty in 3.6magmagstat.errorfloatnullable4.5mag[10.2/26] Spitzer/IRAC 4.5um band magnitudemagphot.mag;em.IR.4-8umfloate_4.5mag[0.04/45]? Uncertainty in 4.5magmagstat.errorfloatnullable5.8mag[9.5/22.7] Spitzer/IRAC 5.8um band magnitudemagphot.flux.density;em.IR.4-8umfloate_5.8mag[0.05/45.28] Uncertainty in 5.8magmagstat.errorfloat8.0mag[7.5/16] Spitzer/IRAC 8.0um band magnitudemagphot.flux.density;em.IR.8-15umfloate_8.0mag[0.04/4.2] Uncertainty in 8.0magmagstat.errorfloat3.6-4.5[-6.3/5.8] The (3.6-4.5) micron band colormagphot.color;em.IR;em.IRfloat4.5-5.8[-2.5/8.7] The (4.5-5.8) micron band colormagphot.color;em.IR;em.IRfloat5.8-8.0[0.6/7] The (5.8-8.0) micron band color indexmagphot.color;em.IR;em.IRfloatJ/ApJS/245/14/table1GalaxiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNGC[628/7793] NGC numbermeta.id;meta.mainintprimaryDist[3.3/34.8] Galactic Standard of Reference distance in Mpc from NEDMpcpos.distance;pos.heliocentricfloatm-M[27.6/32.7] Distance modulus from NEDmagphot.mag.distModfloatNc[69/857] Number of chosen coresmeta.numberintMTypeHubble morphological type from NEDsrc.morph.typecharArmArm class from Elmegreen & Elmegreen (1987ApJ...314....3E)meta.codecharR25[1/11] Radius, R_25_, in arcmin from NEDarcminphys.angSizefloatR25kpc[3/28] Radius, R_25_, in kpc from NEDkpcphys.size.radiusfloatScale[16.3/168] Parsec scale for one arcsecondpc/arcsecinstr.scalefloatSFR[0.05/22.8] Star forming rate (1)solMass/yrmeta.idfloatSimbadSimbad column added by the CDSmeta.ref.urlcharNEDNED column added by the CDSmeta.ref.urlcharLEDAmeta.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.main