J/A+A/637/A64ivo://CDS.VizieR/J/A+A/637/A64doi:10.26093/cds/vizier.36370064CDSMorford J.C.Fenech D.M.Prinja R.K.Blomme R.Yates J.A.Drake J.J.,Eyres S.P.S.Richards A.M.S.Stevens I.R.Wright N.J.Clark J.S.,Dougherty S.Pittard J.M.Smith H.A.Vink J.S.2021-04-27T10:58:11Z2020-09-17T07:09:31ZCDS support team

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

cds-question@unistra.frstellar-associationsradio-astronomyinterferometryThe role of massive stars is central to an understanding of galactic ecology. It is important to establish the details of how massive stars provide radiative, chemical, and mechanical feedback in galaxies. Central to these issues is an understanding of the evolution of massive stars, and the critical role of mass loss via strongly structured winds and stellar binarity. Ultimately, and acting collectively, massive stellar clusters shape the structure and energetics of galaxies. We aim to conduct high-resolution, deep field mapping at 21cm of the core of the massive Cygnus OB2 association and to characterise the properties of the massive stars and colliding winds at this waveband. We used seven stations of the e-MERLIN radio facility, with its upgraded bandwidth and enhanced sensitivity to conduct a 21cm census of Cygnus OB2. Based on 42 hours of observations, seven overlapping pointings were employed over multiple epochs during 2014 resulting in 1{sigma} sensitivities down to ~21{mu}Jy and a resolution of ~180mas. A total of 61 sources are detected at 21cm over a ~0.48{deg}x0.48{deg} region centred on the heart of the Cyg OB2 association. Of these 61 sources, 33 are detected for the first time. We detect a number of previously identified sources including four massive stellar binary systems, two YSOs, and several known X-ray and radio sources. We also detect the LBV candidate (possible binary system) and blue hypergiant star of Cyg OB2 #12. The 21cm observations secured in the COBRaS Legacy project provide data to constrain conditions in the outer wind regions of massive stars; determine the non-thermal properties of massive interacting binaries; examine evidence for transient sources, including those associated with young stellar objects; and provide unidentified sources that merit follow-up observations. The 21cm data are of lasting value and will serve in combination with other key surveys of Cyg OB2, including Chandra and Spitzer.2020A&A...637A..64Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/637/A64CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)J/ApJS/149/123 : WSRT survey of Cygnus OB2 (Setia Gunawan+, 2003)J/A+A/472/557 : Cygnus OB2 region 610MHz sources (Marti+, 2007)J/ApJS/184/84 : X-ray sources in Cyg OB2 region (Wright+, 2009)J/A+A/536/A31 : Cyg OB2 XMM observations (Rauw, 2011)J/ApJS/202/19 : riz photometry in Cyg OB2 (Guarcello+, 2012)J/ApJ/773/135 : Disk-bearing stars in Cygnus OB2 (Guarcello+, 2013)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/637/A64https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/637/A64http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/637/A64https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/637/A64https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/637/A64http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/637/A64GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/637/A64/tablea1 (COBRaS L-band All Source Catalogue)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/637/A64/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/637/A64/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/637/A64/tablea1?GETtext/xml+votable180.050000true308.012708341.17502780.0055555555555555566/14692-146939.459244390355668e-25 9.459244390355668e-25https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/637/A64?format=asciiRadiodefaultJ/A+A/637/A64/tablea1COBRaS L-band All Source CataloguerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCLASCIdentification number given to the sources from this work, sequentially increasing in order of right ascensionmeta.id;meta.mainintm_CLASC[abc] Multiplicity index on CLASCmeta.code.multipcharONameAny other identifier the source may have from a previous identification (G1)meta.idcharRAJ2000Right ascension (J2000) (2)pos.eq.ra;meta.mainDEJ2000Declination (J2000) (2)pos.eq.dec;meta.mainF11th? 21cm integrated flux density from April 11 observationsuJyphot.flux.density;em.radio.750-1500MHzintnullablee_F11th? 21cm Integrated flux density 1{sigma} RMS noise leveluJystat.errorintnullablen_F11th[+d] Note on F11th (4)meta.notecharsigma11th{sigma} within an 3" radius surrounding the edge of the source for April 11 observationsuJy/beamphot.flux.density;em.radio.750-1500MHzintS/N11th? Signal-to-noise ratio for April 11 observations (3)stat.snrfloatnullableF26th? 21cm integrated flux density from April 26 observationsuJyphot.flux.density;em.radio.750-1500MHzintnullablee_F26th? 21cm Integrated flux density 1{sigma} RMS noise leveluJystat.errorintnullablen_F26th[+d] Note on F26th (4)meta.notecharsigma26th{sigma} within an 3" radius surrounding the edge of the source for April 26 observationsuJy/beamphot.flux.density;em.radio.750-1500MHzintS/N26th? Signal-to-noise ratio for April 26 observations (3)stat.snrfloatnullableJ/A+A/637/A64/tablea2Source identification informationrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCLASCID number of each source from CLASC as given in TableA1meta.id;meta.mainintONameAny existing common identifier (G1)meta.idcharOffsetOffset between the position of the CLASC source and that of the identificationarcsecpos.angDistancefloatlambda? Calculated values lambda (see Eq. (3)) (1)stat.fit.paramdoublenullabler? Calculated values r (see Eq. (3)) (1)stat.fit.paramfloatnullablel_LRLimit flag on LRmeta.code.errorcharLRCalculated values LR (see Eq. (3)) (1)stat.fit.paramfloatRefReference to the observations or survey from which each identification is taken (2)meta.ref;pos.frame;obscharNotesAny additional information regarding the flux density, magnitude, or X-ray flux of each identificationmeta.noteJ/A+A/637/A64/tablea3Information regarding the spatial extent of each of the 61 CLASC sources on the sky as measured with the e-MERLIN interferometerrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCLASCIdentification number of each source from CLASC as given in TableA1meta.id;meta.mainintm_CLASC[abc] Multiplicity index on CLASCmeta.code.multipcharA/sigma11th? Source area (S: in pixels) divided by the beam area ({sigma}_beam_: in pixels), as measured by SEAC for the sources detected in the April 11 epochphys.areafloatnullablen_A/sigma11thIndication of whether each source is resolved (Y) or not (N)meta.notecharSint/Sp11th? Ratio of the integrated flux density (Sint) to the peak pixel flux density (Speak) of each of the CLASC sources (as measured by SEAC), for the April 11 epochphot.flux;arith.ratiofloatnullablen_Sint/Sp11thIndication of whether each source is resolved (Y) or not (N)meta.notecharRatio11th? Convolved angular area for the April 11 epoch (1)phys.angAreafloatnullablen_Ratio11thIndication of whether each source is resolved (Y) or not (N)meta.notecharMaj11th? Major axis of the deconvolved angular sizes across April 11 epochs (2)phys.angSizefloatnullablee_Maj11th? rms uncertainty on Maj11thstat.errorfloatnullableMin11th? Minor axis of the deconvolved angular sizes across April 11 epochs (2)phys.angSize;srcfloatnullablee_Min11th? rms uncertainty on Min11thstat.errorfloatnullablen_Maj11th[LAS ] LAS when Maj11th is the convolved largest angular sizemeta.notecharA/sigma24th? Source area (S: in pixels) divided by the beam area ({sigma}_beam_: in pixels), as measured by SEAC for the sources detected in the April 24 epochphys.areafloatnullablen_A/sigma24thIndication of whether each source is resolved (Y) or not (N)meta.notecharSint/Sp24th? Ratio of the integrated flux density (Sint) to the peak pixel flux density (Speak) of each of the CLASC sources (as measured by SEAC), for the April 24 epochphot.flux;arith.ratiofloatnullablen_Sint/Sp24thIndication of whether each source is resolved (Y) or not (N)meta.notecharRatio24th? Convolved angular area for the April 24 epoch (1)phys.angAreafloatnullablen_Ratio24thIndication of whether each source is resolved (Y) or not (N)meta.notecharMaj24th? Major axis of the deconvolved angular sizes across April 24 epochs (2)phys.angSizefloatnullablee_Maj24th? rms uncertainty on Maj24thstat.errorfloatnullableMin24th? Minor axis of the deconvolved angular sizes across April 24 epochs (2)phys.angSize;srcfloatnullablee_Min24th? rms uncertainty on Min24thstat.errorfloatnullablen_Maj24th[LAS ] LAS when Maj24th is the convolved largest angular sizemeta.notechar