Name of the Speaker(s): Aldo Treves
Institution: SISSA
Title of the communication:
Host galaxies of three radio selected BL Lac objects :
Comparison of HST and ground based imaging
Preliminary abstract:
We present images of three BL Lac objects investigated using the
Hubble Space Telescope with the WFPC2 camera.
For 1823+56,and 2254+07 a surrounding nebulosity is detected
while for 0814+49 no extended emission is revealed.
The derived properties of the host galaxies lead to
question the redshift reported for 0814+49 and
possibly for 1823+56.
The results are compared with high quality ground based images
collected at NOT, ESO-NTT and retrieved from CFHT archive.
The agreement between HST and ground based data
is remarkably good on the largest scales, while
the superiority of HST is evident close to the nucleus.