J/A+A/660/A83ivo://CDS.VizieR/J/A+A/660/A83doi:10.26093/cds/vizier.36600083CDSSanchez-Garcia M.Garcia-Burillo S.Pereira-Santaella M.Colina L.,Usero A.Querejeta M.Alonso-Herrero A.Fuente A.2022-09-07T14:11:55Z2022-04-13T12:53:02ZCDS support team

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

cds-question@unistra.frseyfert-galaxiesradio-astronomyThe current understanding of star formation (SF) contemplates that the regulation of this phenomenon in galaxy disks reflects a complex balance between processes that operate in molecular gas on local cloud-scales but also on global disk-scales. We analyse the influence of the dynamical environment on the SF relations of the dense molecular gas in the starburst (SB) ring of the Seyfert 2 galaxy NGC 1068. We used ALMA to image the emission of the 1-0 transitions of HCN and HCO^+^, which trace dense molecular gas in the r~1.3kpc SB ring of NGC 1068, with a resolution of 56pc. We also used ancillary data of CO(1-0), as well as CO(3-2) and its underlying continuum emission at the resolutions of 100pc and 40pc, respectively. These observations allow us to probe a wide range of molecular gas densities (n_H2_~10^3-5^cm^-3^). The SF rate (SFR) in the SB ring of NGC 1068 is derived from Pa{alpha} line emission imaged by HST/NICMOS. We analysed how different formulations of SF relations change depending on the adopted aperture sizes and on the choice of molecular gas tracer. The scatter in the Kennicutt-Schmidt relation, linking the SFR density (SFR) with the (dense) molecular gas surface density ({SIGMA}_dense_), is about a factor of two to three lower for the HCN and HCO^+^ lines compared to that derived from CO(1-0) for a common aperture. Correlations lose statistical significance below a critical spatial scale 300-400pc for all gas tracers. The efficiency of SF of the dense molecular gas, defined as SFE_dense_={SIGMA}SFR_/{SIGMA}_dense_, shows a scattered distribution as a function of the HCN luminosity (L0(HCN)) around a mean value of ~=0.01Myr^-1^. An alternative prescription for SF relations, which includes the dependence of SFE_dense_ on the combination of {SIGMA}_dense_ and the velocity dispersion ({sigma}), resolves the degeneracy associated with the SFE_dense_-L'(HCN) plot. The SFE_dense_ values show a positive trend with the boundedness of the gas, measured by the parameter b={SIGMA}_dense_/{sigma}^2^.We identify two branches in the SFE_dense_-b plot that correspond to two dynamical environments within the SB ring, which are defined by their proximity to the region where the spiral structure is connected to the stellar bar. This region corresponds to the crossing of two overlapping density wave resonances, where an increased rate of cloud-cloud collisions would favour an enhanced compression of molecular gas. These results suggest that galactic dynamics plays a major role in the efficiency of the gas conversion into stars. Our work adds supporting evidence that density-threshold star formation models, which argue that the SFE_dense_ should be roughly constant, fail to account for spatially resolved SF relations of dense gas in the SB ring of NGC 1068.2022A&A...660A..83Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/660/A83CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/549/A39 : A 3mm molecular line survey of NGC1068 (Aladro+, 2013)J/A+A/565/A71 : NGC1068 MIDI/VLTI observations (Lopez-Gonzaga+, 2014)J/A+A/602/A78 : NGC1068 interferometric mid-IR measurementsJ/A+A/632/A61 : NGC1068 CO and HCO images (Garcia-Burillo+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/660/A83https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/660/A83http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/660/A83https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/660/A83https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/660/A83http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/660/A83GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/660/A83/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/660/A83/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/660/A83/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/660/A83/list?GETtext/xml+votable180.050000true40.66986-0.013310.0055555555555555566/17754https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/660/A83?format=asciiRadiodefaultJ/A+A/660/A83/listList of fits imagesNxNumber of pixels along X-axismeta.numberintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainNyNumber of pixels along Y-axismeta.numberintsizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitschar