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For refcode 1997MNRAS.288....1P:
Retrieve 52 NED objects in this reference.
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NED Abstract

Copyright by Royal Astronomical Society. 1997MNRAS.288....1P X-ray emission and internal kinematics in early-type galaxies - I. Observations S. Pellegrini, E. V. Held and L. Ciotti Accepted 1997 January 3. Received 1996 October 15; in original form 1996 June 19 ABSTRACT Long-slit spectroscopic data for seven early-type galaxies with X-ray emission have been analysed to derive velocity dispersion and radial velocity profiles. Major axis rotation curves out to R ~ R_e_ are presented. Adding these new data to those available in the literature, we have built a sample of early-type galaxies with detected X-ray emission and known kinematics (central velocity dispersion {sigma}_c_ and maximum rotational velocity V_rot_). This sample is used to investigate from an observational point of view the role of rotation and flattening in the X- ray emission, particularly with regard to the X-ray underluminosity of flat systems. The trend between the X-ray to optical ratio L_X_/L_B_, a measure of the hot gas content of the galaxies, and V_rot_/{sigma}_c_ is L-shaped, with the X-ray-brightest objects confined at V_rot_/{sigma}_c_ <~ 0.4, for both Es and S0s. Neither for low or intermediate L_X_/L_B_ nor for high L_X_/L_B_ is there any clear correlation between X-ray emission and rotational properties. The trend between L_X_/L_B_ and the ellipticity {epsilon} is also L-shaped, and resembles that between L_X_/L_B_ and v_rot_/{sigma}_c_: there are no high-L_X_/L_B_ objects with high {epsilon}{. The relationships between L_X_/L_B_, the anisotropy parameter (v/{sigma})^*^, and the isophotal shape parameter a_4_/a have also been analysed, but no significant trends have been found. The existence of a relation between v_rot_/{sigma}_c_ and {epsilon} makes it difficult to assess on purely observational grounds whether rotation or flattening is the basis of the L-shaped trends found, although the trend with v_rot_/{sigma}_c_ is sharper than that with {epsilon}. Our observational findings are discussed in connection with the effects that rotation and flattening are predicted to have in the steady-state cooling flow and in the evolutionary wind/outflow/inflow scenarios for the hot gas behaviour. Key words: galaxies: elliptical and lenticular, cD - galaxies: ISM - galaxies: kinematics and dynamics - galaxies: structure - X-rays: galaxies.
Retrieve 52 NED objects in this reference.
Please click here for ADS abstract

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