We present the X-ray luminosity functions (XLFs) of low-mass X-ray binaries (LMXBs) determined for old elliptical galaxies, NGC 3379 and NGC 4278. Because both galaxies contain little diffuse emission from the hot ISM and no recent significant star formation (hence no high-mass X-ray binary contamination), they provide two of the best homogeneous samples of LMXBs. With 324 and 458 ks Chandra ACIS exposures, we detect 93 and 168 LMXBs within the D25 ellipse of NGC 3379 and NGC 4278, respectively. The resulting XLFs exhibit quite different characteristics between LMXBs in GCs and in the field at lower luminosities.
Kim D.W., Fabbiano G., Kalogera V., King A. R., Pellegrini S., Trinchieri G., et al. (2008). The X-ray Luminosity Function of Low Mass X-ray Binaries in Normal Elliptical Galaxies: Globular Clusters versus field LMXB. WASHINGTON, DC : American Astronomical Society.
The X-ray Luminosity Function of Low Mass X-ray Binaries in Normal Elliptical Galaxies: Globular Clusters versus field LMXB
PELLEGRINI, SILVIA;
2008
Abstract
We present the X-ray luminosity functions (XLFs) of low-mass X-ray binaries (LMXBs) determined for old elliptical galaxies, NGC 3379 and NGC 4278. Because both galaxies contain little diffuse emission from the hot ISM and no recent significant star formation (hence no high-mass X-ray binary contamination), they provide two of the best homogeneous samples of LMXBs. With 324 and 458 ks Chandra ACIS exposures, we detect 93 and 168 LMXBs within the D25 ellipse of NGC 3379 and NGC 4278, respectively. The resulting XLFs exhibit quite different characteristics between LMXBs in GCs and in the field at lower luminosities.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
