The HST Survey of BL~Lacertae Objects. IV. Infrared Imaging of Host Galaxies

摘要: The HST NICMOS Camera 2 was used for H-band imaging of 12 BL Lacertae objects taken from the larger sample observed with WFPC2 in R band (Urry et al. 2000; Scarpa 2000). Ten Lacs are clearly resolved, and detected host galaxies large, bright ellipticals average absolute magnitude M=-26.2+-0.45 mag effective radius 10+-5 kpc. rest-frame integrated color is on R-H=2.3+-0.3, consistent value both radio normal, non-active elliptical galaxies, indicating dominant stellar population old. tend to be bluer their outer regions than cores, gradient Delta(R-H)/Delta(log r)=-0.2 mag, again results normal galaxies. infrared Kormendy relation, derived first time Lac m(e) = 3.8*log(R)+14.8 (where surface brightness at R), fully agreement relation ellipticals. close similarity between suggests active nucleus has surprisingly little effect galaxy. This supports a picture which all harbor black holes can actively accreting some fraction lifetime.