4 papers
On the c-theorem in more than two dimensions
A. Cappelli, G. D'Appollonio, R. Guida +1
Several pieces of evidence have been recently brought up in favour of the c-theorem in four and higher dimensions, but a solid proof is still lacking. We present two basic results…
Is the [CO] index an age indicator for star forming galaxies?
L. Origlia, E. Oliva
The classical [CO] index, i.e. the strength of the CO first overtone absorption bands starting at 2.29 micron, is sometimes used to constrain the maximum age of star formation even…
Coronal activity among open cluster stars
S. Randich
Focusing on ROSAT results for clusters in the Myr range, I first summarize our current understanding of the X-ray activity - rotation - age relationship. Then, the pr…
X-ray detections of weak Seyfert2's with BeppoSAX
M. Salvati, L. Bassani, R. Della Ceca +3
We report the detection in the X rays of two weak Seyfert2's (NGC3393 and NGC4941) with the Italian-Dutch satellite BeppoSAX. These are among the first sources observed in a sample…