EDP Sciences
Free access
Volume 395, Number 1, November III 2002
Page(s) 17 - 23
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20021213

A&A 395, 17-23 (2002)
DOI: 10.1051/0004-6361:20021213

HE 0435-1223: A wide separation quadruple QSO and gravitational lens

L. Wisotzki1, P. L. Schechter2, 3, H. V. Bradt2, J. Heinmüller1 and D. Reimers4

1  Universität Potsdam, Am Neuen Palais 10, 14469 Potsdam, Germany
2  Dept. of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
3  Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540, USA
4  Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany

(Received 3 July 2002 / Accepted 19 August 2002)

We report the discovery of a new gravitationally lensed QSO, at a redshift z = 1.689, with four QSO components in a cross-shaped arrangement around a bright galaxy. The maximum separation between images is $2\farcs 6$, enabling a reliable decomposition of the system. Three of the QSO components have $g\simeq 19.6$, while component A is about 0.6 mag brighter. The four components have nearly identical colours, suggesting little if any dust extinction in the foreground galaxy. The lensing galaxy is prominent in the i band, weaker in r and not detected in g. Its spatial profile is that of an elliptical galaxy with a scale length of ~ 12 kpc. Combining the measured colours and a mass model for the lens, we estimate a most likely redshift range of 0.3 < z < 0.4. Predicted time delays between the components are $\la$10 days. The QSO shows evidence for variability, with total g band magnitudes of 17.89 and 17.71 for two epochs separated by ~ 2 months. However, the relative fluxes of the components did not change, indicating that the variations are intrinsic to the QSO rather than induced by microlensing.

Key words: quasars: individual: HE 0435-1223 -- quasars: general -- gravitational lensing

Offprint request: L. Wisotzki, lutz@astro.physik.uni-potsdam.de

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