Artigo Acesso aberto Revisado por pares

ESO & NOT photometric monitoring of the Cloverleaf quasar

1997; EDP Sciences; Volume: 126; Issue: 3 Linguagem: Inglês

10.1051/aas

ISSN

1286-4846

Autores

R. H. Østensen, M. Rémy, P. O. Lindblad, S. Refsdal, R. Stabell, Jean Surdej, P. D. Barthel, P.-I. Emanuelsen, L. Festin, E. Gosset, O. Hainaut, Pasi Hakala, M. Hjelm, J. Hjorth, Damien Hutsemékers, M. Jablonski, A. A. Kaas, H. Kristen, S. Larsson, Pierre Magain, B. Pettersson, Anna Pospieszalska-Surdej, A. Smette, J. Teuber, B. Thomsen, E. van Drom,

Tópico(s)

Adaptive optics and wavefront sensing

Resumo

The Cloverleaf quasar, H1413+117, has been photometrically monitored at ESO (La Silla, Chile) and with the NOT (La Palma, Spain) during the period 1987–1994. All good quality CCD frames have been successfully analysed using two independent methods (i.e. an automatic image decomposition technique and an interactive CLEAN algorithm). The photometric results from the two methods are found to be very similar, and they show that the four lensed QSO images vary significantly in brightness (by up to 0.45 mag), nearly in parallel. The lightcurve of the D component presents some slight departures from the general trend which are very likely caused by micro-lensing effects. Upper limits, at the 99% confidence level, of 150 days on the absolute value for the time delays between the photometric lightcurves of this quadruply imaged variable QSO, are derived. This is unfortunately too large to constrain the lens model but there is little doubt that a better sampling of the lightcurves should allow to accurately derive these time delays. Pending a direct detection of the lensing galaxy (position and redshift), this system thus constitutes another good candidate for a direct and independent determination of the Hubble parameter.

Referência(s)