Abstract
The evolution in X-ray properties of early-type galaxies is largely unconstrained. In particular, little is known about how, and if, remnants of mergers generate hot gas haloes. Here we examine the relationship between X-ray luminosity and galaxy age for a sample of early-type galaxies. Comparing normalized X-ray luminosity to three different age indicators, we find that L-X/L-B increases with age, suggesting an increase in X-ray halo mass with time after the last major star formation episode of a galaxy. The long-term nature of this trend, which appears to continue across the full age range of our sample, poses a challenge for many models of hot halo formation. We conclude that models involving a declining rate of type Ia supernovae, and a transition from outflow to inflow of the gas originally lost by galactic stars, offer the most promising explanation for the observed evolution in X-ray luminosity.
Original language | English |
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Pages (from-to) | 420-426 |
Number of pages | 7 |
Journal | Royal Astronomical Society. Monthly Notices |
Volume | 324 |
Issue number | 2 |
DOIs | |
Publication status | Published - 1 Jun 2001 |
Keywords
- X-rays : galaxies
- galaxies : elliptical and lenticular, cD
- galaxies : interactions
- galaxies : evolution