We present preliminary results of a Chandra/XMM-Newton joint analysis on a sample of three Early Type Galaxies (ETGs, namely NGC4649, NGC4636 and NGC5846). X-ray observations of the hot ISM is used to measure the total enclosed mass assuming hydrostatic equilibrium, and compasion with mass distributions obtained through optical kinematics data of globular clusters and planetary nebulae yields informations about disturbances in the ISM distribution due to nuclear activity, merging history, etc. Our analysis makes use of the Chandra Galaxy Atlas (CGA) data products - exploiting the unmatched spatial resolution of the ACIS detectors to reveal fine ISM features and disturbances in the inner galactic regions - and XMM-Newton data - relying on the large field of view of EPIC detector to extend the mass profiles to larger radii. We then measured the mass profiles in various pie sectors to separate different gas features (e.g., discontinuity and extended tail) and compared them with GCs/PNe based mass profiles. The X-ray mass profiles of NGC4649 show a generally relaxed morphology and, in agreement with previous analysis, the comparison with the optical mass profiles shows a significant deviations on parsec scale likely due to non-thermal pressure linked to nuclear activity. In significantly disturbed cases (NGC4648 and NGC5846) where we found discontinuities and extended tails, we found that the mass profiles are over-estimated toward the compressed discontinuity and under-estimated toward the extended tails, similar to inflow and outflow cases. These preliminary results are promising toward an extended analysis of the whole CGA sample in order to study the distribution of gas temperature and metal abundances in the ISM, and to investigate scaling relations between ETG global quantities like ISM temperature, luminosity and total mass.
AAS/High Energy Astrophysics Division #15
- Pub Date:
- April 2016