Zobrazeno 1 - 10
of 26
pro vyhledávání: '"U. Borgeest"'
Autor:
Mark R. Kidger, R. Rekola, H. Pietilä, R. K. Honeycutt, Merja Tornikoski, K. Nilsson, G. Poyner, G. M. Richter, N. M. Shakhovskoy, N. Gonzalez-Perez, H. Teräsranta, Philip A. Hughes, S. Katajainen, M. G. Nikolashvili, J. V. Linde, W. Weneit, G. de Francesco, Mauri Valtonen, E. Massaro, Jochen Heidt, S. Wiren, Jeff W. Robertson, Roberto Nesci, Leo O. Takalo, F. Montagni, A. Riehokainen, A. C. Sadun, Omar M. Kurtanidze, Stefan Wagner, Pekka Heinämäki, C. M. Raiteri, J. A. de Diego, Deborah Dultzin-Hacyan, P. A. Charles, John K. Webb, E. Valtaoja, Alan P. Marscher, Margo F. Aller, P. Boltwood, M. Hanski, Pasi Nurmi, M. Maesano, M. Kümmel, G. Sobrito, Massimo Fiorucci, Markku Lainela, Volker Beckmann, Pekka Teerikorpi, J. M. Rodriguez-Espinoza, T. Mahoney, U. Borgeest, Hugh D. Aller, K. J. Schramm, L. Lanteri, M. Villata, Lewis B. G. Knee, Matthias Dietrich, D. Kühl, Erika Benítez, Anne Lähteenmäki, Harry J. Lehto, G. Tosti, Yu. S. Efimov, H. Bock, A. Sillanpää, S. G. Marchenko, G. W. Turner, T. Pursimo, G. Ghisellini, T. Schramm, K. Karlamaa
Publikováno v:
Scopus-Elsevier
We present intensive optical, infrared, and radio monitoring observations of the BL Lac object OJ 287, taken between the years 1993-1998. Two large optical outbursts were detected at the predicted times in November 1994 and December 1995. The detecti
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4a80ea3ab9785496d68bf9734ffb35d8
https://doi.org/10.1051/aas:2000264
https://doi.org/10.1051/aas:2000264
Autor:
Jochen Schramm, U. Borgeest
Publikováno v:
Gravitational Lenses ISBN: 9783540557975
We carry out an optically broad-band photometric monitoring program of quasars using the MPIA 1.23 m telescope equipped with a CCD camera. The frames are reduced automatically within a few minutes after each exposure. More than 70 quasars, selected a
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::d31322c144cf08342204fb7738186826
https://doi.org/10.1007/3-540-55797-0_98
https://doi.org/10.1007/3-540-55797-0_98
Autor:
Jochen Schramm, U. Borgeest
Publikováno v:
Gravitational Lenses ISBN: 9783540557975
In this contribution, we treat the following aspects of gravitational microlensing: 1. the idea of Ostriker & Vietri that some BL Lac objects might be microlensed blazars, 2. the proposal that the variations of some optically violent variables (OVVs)
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::324c1e1f1bfd3fa617f86ed6231bf478
https://doi.org/10.1007/3-540-55797-0_97
https://doi.org/10.1007/3-540-55797-0_97
Publikováno v:
Gravitational Lensing ISBN: 354052648X
In May 1989 we started an extensive monitoring program in order to find and analyse micro-lensing events in the light curves of a selected sample of quasars. We use the MaxPlanck-Institute 1.23 m telescope at the German-Spanish Astronomical Centre on
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::bfefea3a9cffaed2f930240f0855969a
https://doi.org/10.1007/bfb0009256
https://doi.org/10.1007/bfb0009256
Publikováno v:
Variability of Active Galaxies ISBN: 3540538607
In May 1989 we started an extensive optical photometric monitoring program of quasars which are promising candidates for gravitational microlensing. We use the Calar Alto 1.2m telescope equipped with a CCD camera to obtain the quasar fluxes relative
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::dc9d74022ef104693b276f353745bfa1
https://doi.org/10.1007/bfb0030074
https://doi.org/10.1007/bfb0030074
Publikováno v:
Examining the Big Bang and Diffuse Background Radiations ISBN: 9780792338154
Under the auspices of Sjur Refsdal, 25 astrophysicists and engineers from Germany and Scandinavia have founded a non-profit association, aiming at the use of an intelligent telescope for quasar monitoring in the optical (Borgeest et. al. 1993). Beyon
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::6fc9de3e95fff33ce3962d28df67bf8f
https://doi.org/10.1007/978-94-009-0145-2_70
https://doi.org/10.1007/978-94-009-0145-2_70
Publikováno v:
Astrophysical Applications of Gravitational Lensing ISBN: 9780792339557
In order to look for an amplification bias (AB) by gravitational lensing caused by medium redshift (0.2 ≲ z ≲ 0.8) clusters or groups of galaxies, we compare galaxy counts in deep CCD images of highly luminous, high redshift QSOs with those in ne
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::690f24b3e41bdd67147e3d26fd9e8e6d
https://doi.org/10.1007/978-94-009-0221-3_84
https://doi.org/10.1007/978-94-009-0221-3_84
Publikováno v:
Examining the Big Bang and Diffuse Background Radiations ISBN: 9780792338154
We compare galaxy counts in deep R-band exposures of the fields of 36 highly luminous, high redshift QSOs to those in control fields at a distance of 1 deg. We find indication for a weak overdensity of galaxies in the foreground of QSOs on scales of
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::b0b094a8a13a06b0cb9753f34b1d7d4a
https://doi.org/10.1007/978-94-009-0145-2_61
https://doi.org/10.1007/978-94-009-0145-2_61
Publikováno v:
Multi-Wavelength Continuum Emission of AGN ISBN: 9780792327455
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::818fdf3533dd306f9b42d3d87d7867f5
https://doi.org/10.1007/978-94-010-9537-2_105
https://doi.org/10.1007/978-94-010-9537-2_105
Publikováno v:
Gravitational Lenses ISBN: 9783540557975
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::01f53ed1d5f6c6ecf9e374c5ba0fbacb
https://doi.org/10.1007/3-540-55797-0_107
https://doi.org/10.1007/3-540-55797-0_107