Detection of the lensing galaxy for the double QSO HE 1104-1805
DOI: 10.1016/S1384-1076(98)00005-0 (http) or 10.1016/S1384-1076(98)00005-0 (doi)
ADS bibcode 1998NewA....3..379R
M. Remy [1], J.-F. Claeskens [1], J. Surdej [1], J. Hjorth [2], S. Refsdal [3], O. Wucknitz [3], A.N. Sørensen [4], F. Grundahl [5]
- Institut d'Astrophysique et de Géophysique, Universitéde Liège, Avenue de Cointe 5, B-4000 Liège, Belgium
- Nordic Institute for Theoretical Physics, Blegdamsvej 17, DK-2100 Copenhagen Ø, Denmark
- Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg, Germany
- Copenhagen University Observatory, Niels Bohr Institute for Astronomy, Physics and Geophysics, Juliane Maries Vej 30, DK-2100 Copenhagen Ø, Denmark
- Dominion Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council of Canada, 5071 W. Saanich Road, Victoria, BC. V8X 4M6, Canada
Abstract
High angular resolution ground-based direct imaging (V, R, Ic) of the
double QSO HE 1104-1805 has been obtained with the NOT and NTT
telescopes. Analysis of these data led to the first detection of the
lensing galaxy. Direct imaging of HE 1104-1805 has subsequently been
carried out with the Planetary Camera (WFPC2) through the F555W
(nearly Johnson V) and F814W (nearly Kron-Cousins Ic) filters onboard
HST. These images confirm the presence of the deflector between the
two lensed quasar components (A & B). Direct imaging of this system in
the near infrared (IR) at 2.2 mu (K'), with IRAC-2b at the Cassegrain
focus of the ESO/MPI 2.2 m telescope, indicates that the additional
component is indeed a very red extended object with magnitude K ca.
16.5. We present deconvolutions of the HST and IR images using the
2-channel PLUCY method. From the HST observations, we also report very
accurate relative positions and brightnesses of the QSO components. By
comparison between the ground-based and the HST observations, from
February-March 1994 to November 1995, we possibly detect the fading of
component A by ca. 0.3 magnitudes in the optical and a corresponding
fading of B by about half this value. The observed monotonic decrease
of the magnitude difference between B and A as a function of
wavelength is consistent with a partial amplification of the A
component by microlensing. Evolutionary models for galaxies show that,
in order to produce the observed colour indices V-Ic > 2 and 4 < Ic-K
< 4.5, the galaxy is likely to be of elliptical type with a redshift
0.95 < z < 1.4. This range is consistent with the redshift z = 1.32
measured from the absorption lines of metallic species in the spectra
of the quasar components. However, other values for the redshift of
the lens inside this range cannot be excluded. This galaxy would
presently be among the most distant known gravitational
lenses. Several theoretical models are found to fit the
observations. The simplest one is a singular isothermal sphere (SIS)
lens immersed in an external shear with gamma = 0.123. The derived
mass-to-light ratio (11 h50 M0/L0) for the galaxy is large but does not
imply an excess of dark matter with respect to other well known
lensing galaxies.
Key words:
gravitational lensing; quasars: individual: HE 1104-1805; techniques: image processing
New Astronomy 3 (1998) 379 (link to online journal)
DOI (Digital Object Identifier): 10.1016/S1384-1076(98)00005-0 (http) or 10.1016/S1384-1076(98)00005-0 (doi)
ADS bibcode 1998NewA....3..379R (link to ADS entry)
download full article
gzipped postscript file (277.5 kB, last change 18 Aug 1998)
unzipped postscript file (1.7 MB)
To publications
To my homepage
To the AIfA
To the University of Bonn
Script last modified on 7 Sep 2010
Last change to this data base entry on 3 Jul 2002