J/A+A/505/405ivo://CDS.VizieR/J/A+A/505/405doi:10.26093/cds/vizier.35050405CDSPeretto N.Fuller G.A.2017-06-26T11:49:53Z2009-12-25T22:31:55ZCDS support team

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

cds-question@unistra.frinfrared-sourcesmolecular-cloudsgalaxy-classification-systemsThe majority of stars form in clusters. Therefore a comprehensive view of star formation requires understanding the initial conditions for cluster formation. The goal of our study is to shed light on the physical properties of infrared dark clouds (IRDCs) and the role they play in the formation of stellar clusters. This article, the first of a series dedicated to the study of IRDCs, describes techniques developed to establish a complete catalogue of Spitzer IRDCs in the Galaxy. We have analysed Spitzer GLIMPSE and MIPSGAL data to identify a complete sample of IRDCs in the region of Galactic longitude and latitude 10{deg}<|l|<65{deg} and |b|<1{deg}. From the 8um observations we have constructed opacity maps and used a newly developed extraction algorithm to identify structures above a column density of N_H2_=1x10^22^cm^-2^. The 24um data are then used to characterize the star formation activity of each extracted cloud. A total of 11303 clouds have been extracted. A comparison with the existing MSX based catalogue of IRDCs shows that 80% of these Spitzer dark clouds were previously unknown. The algorithm also extracts ~20000 to 50000 fragments within these clouds, depending on detection threshold used.A first look at the MIPSGAL data indicates that between 20% and 68% of these IRDCs show 24um point-like association. This new database provides an important resource for future studies aiming to understand the initial conditions of star formation in the Galaxy.2009A&A...505..405Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/505/405CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/639/227 : MSX IRDC candidate catalog (Simon+, 2006)J/ApJ/641/389 : Millimetric observations of IRDC cores (Rathborne+, 2006)J/A+A/590/A72 : Herschel counterparts of SDC (Peretto+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/505/405https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/505/405http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/505/405https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/505/405https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/505/405http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/505/405GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/505/405/table1 (IRDC properties)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/505/405/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/505/405/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/505/405/table1?GETtext/xml+votable180.050000true271.3767083-20.88777780.0055555555555555565/3588-3589 7275 7278 7376-7377 7383 7554 7564 7578-7579 7604-7605 7651 7654 7672 7678-7679 10413-10414 10419-10420 10444-10445 10450-10451 10453 10542-10543 10553 10556 10594-10595 10599 10609 10611 10624 10760 6/12969-12971 12974-12975 14337 14340-14341 14343 14402-14403 14406 14408-14409 14412-14413 28919 29090-29091 29094-29097 29099 29116 29118-29119 29162-29163 29456 29460-29461 29463 29513 29516 29522-29523 29526 29528-29529 29531 30222-30223 30240-30241 30243-30245 30247 30260 30262-30263 30265 30268-30269 30306-30307 30328 30330-30331 30334 30404-30405 30429 30592 30594-30595 30599 30601 30603 30620 30622-30623 30644-30645 30666 30692 30694-30695 30700-30701 30706-30707 30710 32085 37893 37895 37904-37906 41595 41597-41599 41651 41660-41662 41670-41671 41673-41675 41684-41686 41688-41689 41696-41698 41700 41755 41758-41759 41763 41765-41770 41772-41773 41784 41798-41799 41809-41811 41816-41817 41820-41821 41824-41825 41856 42155 42158-42159 42166 42206-42207 42209-42211 42216-42218 42220-42221 42228-42230 42375 42386-42387 42389-42393 42401 42434-42435 42440-42441 42449-42451 42456 42458 42500-42502 42512-42513 43013-43015 43017-43022 43024-43026https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/505/405?format=asciiInfraredOpticaldefaultJ/A+A/505/405/table1IRDC propertiestau.p8micron peak opacity of IRDCphys.absorption.coeff;stat.maxfloatSeqRunning numbermeta.id;meta.mainintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameIRDC (Infra-Red Dark Cloud) name, based on Galactic position (LLL.ll+B.bbb)meta.idcharRAJ2000Right Ascension J2000pos.eq.ra;meta.mainDEJ2000Declination J2000pos.eq.dec;meta.mainIminMinimum intensity within the IRDCMJy/srspect.line.intensityfloatIMIRMid-IR radiation field intensityMJy/srspect.line.intensityfloatdIMIRNormalized variation of IMIRspect.line.intensity;arith.ratiofloatmajMajor axis size of IRDCarcsecphys.angSizefloatminMinor axis size of IRDCarcsecphys.angSizefloatPA[-90,90] Position angle of IRDCdegpos.posAngintReqEquivalent radius of IRDCarcsecphys.angSize;srcfloattau.av8micron averaged opacity of IRDCphys.absorption.coefffloattau.sat8micron saturation opacityinstr.saturationfloatNfrNumber of fragments (with tau_step=0.35: cf paper)meta.numberintField[y/n] 24micron star in the field: y for yes, n for nometa.codecharIRDC[y/n] 24micron star in the IRDC: y for yes, n for nometa.codecharSigma24micron star surface density around the IRDCarcmin**-2src.densityfloat