Astron. Astrophys. 363, 349-354 (2000)

Observing high-redshift supernovae in lensed galaxies

Tarun Deep Saini ¹, Somak Raychaudhury ¹ and Yuri A. Shchekinov <sup>2,3

1</sup> Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Puné, 411007 India (saini, somak@iucaa.ernet.in)
² Department of Physics, Rostov University, Sorge, 5, Rostov on Don, 344090 Russia (yus@rsuss1.rnd.runnet.ru)
³ Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy

Received 23 February 2000 / Accepted 31 July 2000

Abstract

Supernovae in distant galaxies that are gravitationally lensed by foreground galaxy clusters make excellent standard candles for measuring cosmological quantities like the density of the Universe in its various components and the Hubble constant. Distant supernovae would be rendered more easily detectable in the fields of rich galaxy clusters since the latter could act as foreground lenses, magnifying such supernovae by up to 3-4 magnitudes. We show that in the case of the lens cluster Abell 2218, the detectability of high-redshift supernovae is significantly enhanced due to the lensing effects of the cluster. The signal-to-noise ratio for the observation of lensed supernovae will be further enhanced, typically by an order of magnitude, since they will remain point images even when their host galaxies are stretched into arcs by the effect of lensing. We recommend monitoring with medium-sized telescopes well-modelled clusters with several known arclets for the detection of cosmologically useful SNe around and beyond.

Key words: cosmology: gravitational lensing cosmology: distance scale galaxies: clusters: general stars: supernovae: general

Present address: School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK

Send offprint requests to: Tarun Deep Saini

© European Southern Observatory (ESO) 2000

Online publication: December 5, 2000

helpdesk@link.springer.de