Optical imaging of the host galaxies of X-ray selected BL Lacertae objects
| dc.creator | Falomo, R. | |
| dc.creator | Kotilainen, J. K. | |
| dc.date | 1999-10-06 | |
| dc.date.accessioned | 2026-07-07T02:33:42Z | |
| dc.date.available | 2026-07-07T02:33:42Z | |
| dc.description | We investigate the properties of the host galaxies of X-ray selected (high frequency peaked) BL Lac objects using a large and homogeneous data set of high spatial resolution R-band observations of 52 BL Lacs in the EMSS and Slew samples. The redshift distribution of the BL Lacs ranges from z = 0.04 to z>0.7, with average and median redshifts z = 0.26 and z = 0.24, respectively. Eight objects are at unknown redshift. We are able to resolve 45 objects out of the 52 BL Lacs. For all the well-resolved sources, we find the host to be a luminous elliptical galaxy. In a few cases a disk is not ruled out but an elliptical model is still preferred. The average absolute magnitude of the host galaxies is <M_R(host)> = -23.9+-0.6, while the average scale length of the host is <R(e)> = 9+-5 kpc. There is no difference in the host properties between the EMSS and Slew samples. We find a good agreement between the results derived by the surveys of Wurtz et al. (ground-based data) and Urry et al. (HST data), and by our new deeper imaging. The average luminosity of the BL Lac hosts is between those of F-R I and F-R II radio galaxies in Govoni et al., supporting the idea that both radio galaxy types could contribute to the parent population. The BL Lac hosts follow the F-P relation for giant ellipticals and exhibit a modest luminosity evolution with redshift. Finally, we find a slight correlation between the nuclear and host luminosity and a bimodal distribution in the nuclear/host luminosity ratio. | |
| dc.description | 19 pages, Astronomy & Astrophysics, in press | |
| dc.identifier | https://arxiv.org/abs/astro-ph/9910106 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/9910106 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/14952 | |
| dc.subject | Astrophysics | |
| dc.title | Optical imaging of the host galaxies of X-ray selected BL Lacertae objects | |
| dc.type | text |