J/ApJ/914/54ivo://CDS.VizieR/J/ApJ/914/54doi:10.26093/cds/vizier.19140054CDSYadav J.Das M.Patra N.N.Dwarakanath K.S.Rahna P.T.McGaugh S.S.,Schombert J.Murthy J.2023-01-18T06:18:14Z2022-12-29T05:38:49ZCDS support team

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

cds-question@unistra.frgalaxiesultraviolet-astronomystar-forming-regionsWe present a far-UV (FUV) study of the star-forming complexes (SFCs) in three nearby galaxies using the Ultraviolet Imaging Telescope. The galaxies are close to face-on and show significant outer disk star formation. Two of them are isolated (NGC 628 and NGC 6946), and one is interacting with distant companions (NGC 5457). We compared the properties of the SFCs inside and outside the optical radius (R25). We estimated the sizes, star formation rates (SFRs), metallicities, and Toomre Q parameter of the SFCs. We find that the outer disk SFCs are at least 10 times smaller in area than those in the inner disk. The SFRs per unit area ({Sigma}_SFR_) in both regions have similar mean values, but the outer SFCs have a much smaller range of {Sigma}_SFR_. They are also metal-poor compared to the inner disk SFCs. The FUV emission is well correlated with the neutral hydrogen gas (HI) distribution and detected within and near several HI holes. Our estimation of the Q parameter in the outer disks of the two isolated galaxies suggests that their outer disks are stable (Q>1). However, their FUV images indicate that there is ongoing star formation in these regions. This suggests that there may be some nonluminous mass or dark matter in their outer disks, which increases the disk surface density and supports the formation of local gravitational instabilities. In the interacting galaxy, NGC 5457, the baryonic surface density is sufficient (Q<1) to trigger local disk instabilities in the outer disk.2021ApJ...914...54Yhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/914/54CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJS/65/485 : 1.49GHz Atlas of Spiral Galaxies (Condon, 1987)J/MNRAS/382/1552 : Multiwavelength study of nearby galaxy nuclei (Lira+, 2007)J/ApJS/173/538 : XUV-Disk galaxies in the Local Universe (Thilker+, 2007)J/AJ/136/2782 : Star formation efficiency in nearby galaxies (Leroy+, 2008)J/AJ/136/2563 : HI Nearby Galaxy Survey, THINGS (Walter+, 2008)J/AJ/140/1194 : FUV/HI relations in nearby galaxies (Bigiel+, 2010)J/MNRAS/403/683 : GALEX Arecibo SDSS survey (GASS) (Catinella+, 2010)J/AJ/141/23 : HI holes in THINGS galaxies (Bagetakos+, 2011)J/ApJ/733/74 : GALEX - SDSS properties of local galaxies (Lemonias+, 2011)J/A+A/545/A43 : HII regions in NGC 628 and NGC 6946 (Cedres+, 2012)J/AJ/151/136 : LITTLE THINGS dwarf galaxies FUV regions (Hunter+, 2016)J/A+A/600/A6 : NGC628 3.1GHz intensity & polarised images (Mulcahy+, 2017)J/AJ/158/229 : Properties of FUV bright SFRs in IC 2574 (Mondal+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/914/54https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/914/54http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/914/54https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/914/54https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/914/54http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/914/54GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/914/54/table1 (Properties of galaxies)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/914/54/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/914/54/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/914/54/table1?GETtext/xml+votable180.050000true24.17416715.7833330.005555555555555556Cone search capability for table J/ApJ/914/54/table5 (Properties of FUV bright complexes in NGC 0628, NGC 5457, NGC 6946)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/914/54/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/914/54/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/914/54/table5?GETtext/xml+votable180.050000true24.09762515.80056110.005555555555555556Cone search capability for table J/ApJ/914/54/table6 (Q value of star-forming complexes (SFCs) in the outer disk)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/914/54/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/914/54/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/914/54/table6?GETtext/xml+votable180.050000true23.997416715.71470.0055555555555555566/11434 15592-15593 18398https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/914/54?format=asciiUVdefaultJ/ApJ/914/54/table1Properties of galaxiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNGCGalaxy namemeta.id;meta.mainintprimaryRAJ2000Hour of right ascension (J2000) (1)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000) (1)pos.eq.dec;meta.mainDist[5.9/7.4] Distance (1)Mpcpos.distancefloatInc[7/33] Inclination (1)degsrc.orbital.inclinationintPA[20/243] Position angledegpos.posAngintTypeGalaxy type as listed in NEDsrc.morph.typecharScale[28.6/36] Spatial scale of galaxypc/arcsecarith.factorfloatR25[4.89/12] Optical radius R_25_ (1)arcminphys.angSize;em.optfloatSimbadSimbad column added by the CDSmeta.ref.urlcharNEDNED column added by the CDSmeta.ref.urlcharLEDAmeta.ref.urlcharE(B-V)[0.008/0.3] Foreground Galactic extinction taken from Schlafly and Finkbeiner (2011ApJ...737..103S)magphot.color.excessfloatlogSFR[-2.92/-2.25] Log of stellar formation rate surface density (2)log(solMass.yr**-1.kpc**-2)phys.SFR;src.densityfloatNsfcNumber of star-forming complexes in this galaxy (link to Table 5)meta.numberintnullableJ/ApJ/914/54/table5Properties of FUV bright complexes in NGC 0628, NGC 5457, NGC 6946NGCGalaxy namemeta.id.parentintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000[1/20] Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000[15/60] Degree of Declination (J2000)pos.eq.dec;meta.mainamaj[0.7/38.1] Semi-major axisarcsecphys.angSize;srcfloatbmin[0.27/22] Semi-minor axisarcsecphys.angSize.sminAxisfloatPA[0/359] Position angle, South of Eastdegpos.posAngintSFRuv[0.002/3.1] Specific star formation rate from UVsolMass.yr**-1.kpc**-2phys.SFR;src.density;em.UVfloate_SFRuv[0.0009/0.13] Uncertainty in SFR-UVsolMass.yr**-1.kpc**-2stat.errorfloatArea[0.0001/0.0012] Areakpc**2phys.areafloatLocLocation in Galaxy ("Inner": 2534 occurrences or "Outer": 141 occurrences)meta.notecharOutDisplay the Q value measurement for this outer star-forming complex (link to Table 6)meta.ref.urlintnullableJ/ApJ/914/54/table6Q value of star-forming complexes (SFCs) in the outer diskNGCGalaxy namemeta.id.parentintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000[1/20] Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000[15/60] Degree of declination (J2000)pos.eq.dec;meta.mainamaj[0.7/12.9] Semi-major axisphys.angSize;srcfloatbmin[0.5/10] Semi-minor axisphys.angSize.sminAxisfloatPA[1/360] Position angledegpos.posAngintQ[0.07/248.36] the Toomre Q value (1)stat.fit.paramfloate_Q[0.01/37.52] Q uncertaintystat.errorfloatFUVDisplay the FUV measurements for this outer star-forming complex (link to Table 5)meta.ref.urlintnullable