Dark matter in early-type galaxies: dynamical modelling of IC 1459, IC 3370, NGC 3379 and NGC 4105 |
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| Authors: | S Samurovi&#; I J Danziger |
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| Institution: | Dipartimento di Astronomia, Universitàdi Trieste, Via Tiepolo 11, I-34131 Trieste, Italy;INAF, Osservatorio Astronomico di Trieste, Via Tiepolo 11, I-34131 Trieste, Italy;Astronomical Observatory, Volgina 7, 11160 Belgrade, Serbia and Montenegro;Institute Isaac Newton of Chile, Yugoslavia Branch, Serbia and Montenegro |
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| Abstract: | We analyse long-slit spectra of four early-type galaxies which extend from ～1 to 3 effective radii: IC 1459; IC 3370; NGC 3379 and NGC 4105. We have extracted the full line-of-sight velocity distribution (in the case of NGC 3379 we also used data from the literature), which we model using the two-integral approach. Using two-integral modelling, we find no strong evidence for dark haloes, but the fits suggest that three-integral modelling is necessary. We also find that the inferred constant mass-to-light ratio in all the four cases is typical for early-type galaxies. Finally, we also discuss the constraints on the mass-to-light ratio, which can be obtained using X-ray haloes in the case of IC 1459, NGC 3379 and NGC 4105, and compare the estimated values with the predictions from the dynamical modelling. |
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| Keywords: | galaxies: elliptical and lenticular galaxies: kinematics and dynamics galaxies: ISM X-rays galaxies: structure dark matter |
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