Reference : ESO & NOT photometric monitoring of the Cloverleaf quasar
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/22956
ESO & NOT photometric monitoring of the Cloverleaf quasar
English
Ostensen, R. [Institute of Mathematical and Physical Sciences, University of Tromso, N-9037 Tromso, Norway]
Remy, M. [ > > ]
Lindblad, P. O. [Stockholm Observatory, S-13336 Saltsjobaden, Sweden]
Refsdal, S. [Hamburger Sternwarte, Gojenbergsweg 112, D-21029, Germany]
Stabell, R. [ > > ]
Surdej, Jean mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS) >]
Barthel, P. D. [Kapteyn Astronomical Institute, Rijksuniversiteit, Landleven 12, Postbus 800, 9700 AV Groningen, The Netherlands]
Emanuelsen, P. I. [Institute of Mathematical and Physical Sciences, University of Tromso, N-9037 Tromso, Norway]
Festin, L. [Astron. Obs. Box 515, S-751 20 Uppsala, Sweden]
Gosset, Eric mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Groupe d'astrophysique des hautes énergies (GAPHE) >]
Hainaut, O. [Institute for Astronomy, 2680 Woodlawn Drive, Honolulu HI 96822, U.S.A.]
Hakala, P. [Helsinki University Observatory, Tahtitorninmaki, SF-00014 Helsinki, Finland]
Hjelm, M. [Stockholm Observatory, S-13336 Saltsjobaden, Sweden]
Hjorth, J. [NORDITA, Blegdamsvej 17, DK-2100 Copenhagen, Denmark]
Hutsemekers, Damien mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS) >]
Jablonski, M. [Institute of Theoretical Astrophysics, University of Oslo, Box 1029 Blindern, N-0315 Oslo, Norway]
Kaas, A. A. [Stockholm Observatory, S-13336 Saltsjobaden, Sweden]
Kristen, H. [Stockholm Observatory, S-13336 Saltsjobaden, Sweden]
Larsson, S. [Stockholm Observatory, S-13336 Saltsjobaden, Sweden]
Magain, Pierre mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image >]
Pettersson, B. [Astron. Obs. Box 515, S-751 20 Uppsala, Sweden]
Pospieszalska-Surdej, A. [Institut d'Astrophysique, Universite de Liege, Belgium]
Smette, A. [Kapteyn Astronomical Institute, Rijksuniversiteit, Landleven 12, Postbus 800, 9700 AV Groningen, The Netherlands]
Teuber, J. [Copenhagen University Observatory, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark]
Thomsen, B. [Institute of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C, Denmark]
van Drom, E. [Institut d'Astrophysique, Universite de Liege, Belgium]
1-Dec-1997
Astronomy and Astrophysics. Supplement Series
EDP Sciences
126
393-400
Yes (verified by ORBi)
International
0365-0138
Les Ulis
France
[en] GRAVITATIONAL LENSING ; TECHNIQUES: IMAGE PROCESSING ; QUASARS: H1413+117
[en] 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. Based on observations collected at the European Southern Observatory (La Silla, Chile) and with the Nordic Optical Telescope (La Palma, Spain). Table 1. Logbook for the ESO and NOT observations together with photometric results for the Cloverleaf quasar. This long table can be accessed on the WWW at the URL address: http://vela.astro.ulg.ac.be/grav_lens/glp_homepage.html}
Researchers ; Professionals
http://hdl.handle.net/2268/22956
10.1051/aas:1997273
http://adsabs.harvard.edu/abs/1997A%26AS..126..393O
The authors thank EDP Sciences for their deposit authorization

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