J/AJ/108/111ivo://CDS.VizieR/J/AJ/108/111doi:10.26093/cds/vizier.51080111CDSStatler T.S.2023-04-06T16:50:07Z1997-12-09T20:18:19ZCDS support team

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

cds-question@unistra.frgalaxiesvisible-astronomyPhotometric and kinematic data from the literature are combined with new dynamical models to derive the intrinsic shape of the "standard" elliptical galaxy NGC 3379. The parameters that are best constrained are the dynamical triaxiality T (essentially the triaxiality of the total mass distribution) and the short-to-long axis ratio of the light distribution c_L. The inferred shape is given by a Bayesian probability distribution in the (T,c_L) plane. Assuming a uniform prior, the most probable shape is oblate with a flattening of c_L=.87. The distribution is strongly non-Gaussian, however, and the expectation values, <T>=.31, <c_L>=.75, imply a flatter and more triaxial figure. The 68% highest posterior density region allows more triaxial shapes as long as they are fairly round, or flatter shapes as long as they are nearly oblate. These results are essentially unchanged if the galaxy is assumed to rotate about its short axis, or if it is modeled as an S0 with a negligible-mass disk rather than as an elliptical. The suggestion of Capaccioli et al. [ApJ, 371, 535 (1991)] that NGC 3379 is a rather flat, triaxial S0 galaxy is found to be improbable at the 98% level; this conclusion is largely independent of the bulge-to-disk ratio or the relative rotation speeds of the two components. Addresses: Statler T.S. <tss@physics.unc.edu> Department of Physics and Astronomy, CB# 3255, University of North Carolina, Chapel Hill, North Carolina 25799-3255 Objects concerned: ----------------------------------------- RA (2000) DE Names ----------------------------------------- 10 47.8 +12 35 NGC 3379 = UGC 5902 -----------------------------------------1994AJ....108..111Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/108/111CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/108/111https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/108/111http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/108/111https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/108/111https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/108/111http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/108/111GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/108/111/table5NGC 3379 point estimators, see Sect. 4.3 of the printed paper for full detailsphiE4Maximum unprojected likelihood, phiEstat.paramfloatthetaE4Maximum unprojected likelihood, thetaEstat.paramfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIndexIndex to model parameters in tables 1,2,4meta.id;stat.fitintTExpectation value of dynamical triaxialitystat.paramfloatcLExp. value of flattening of light distrib.src.morph.paramfloatTpMost probable value of Tstat.paramfloatcLpMost probable value of cLsrc.morph.paramfloatT4Maximum unprojected likelihood, Tstat.paramfloatcL4Maximum unprojected likelihood, cLstat.likelihoodfloat