Fakultäten » Mathematisch-naturwissenschaftliche Fakultät » Physik-Institut » Prof. Dr. Philippe Jetzer » Jetzer

Completed research project

Title / Titel Gravitational microlensing towards M31 (2010)
PDF Abstract (PDF, 14 KB)
Summary / Zusammenfassung We continued our research activity on gravitational microlensing towards M31. Following our pilot observational campaigns in 2006 and 2007 using the 1.5 m Loiano telescope at the Osservatorio Astronomico di Bologna, we (the PLAN collaboration: Pixel Lensing ANdromeda) got several months observing time at the same telescope in fall 2008 and 2009. The analysis of the 2007 data has been completed and published, whereas for 2008 and 2009 it is still underway. In the 2007 season we found two candidate microlensing events. One event (OAB-N2) was at the end of the observing period, but fortunately the WeCAPP collaboration made observations afterwards. We thus shared the data and the combined analysis shows that with the better coverage the event is nicely con rmed. Using archival 4m-KPNO and HST/WFPC2 data we performed a detailed analysis on the event source whose result, although not fully conclusive on the source magnitude determination, is con rmed by the following light curve photometry analysis. The improved photometry enabled a detailed analysis in the event parameter space including the e ects due to nite source size. The combined results of these analyses allowed us to put a strong lower limit on the lens proper motion. This outcome favours the MACHO lensing hypothesis over self-lensing for this individual event and points the way towards distinguishing between the MACHO and self-lensing hypotheses from larger data sets [1]. We got again observing time at the Loiano telescope for fall 2010. B.1.2 Pixel-lensing as a way to detect extrasolar planets in M31 (Ph. Jetzer) 1 Our paper on the possibility to detect extrasolar planets in M31 through pixel-lensing observation, which attracted a huge interest from the media, appeared in MNRAS [2]. In the following we reanalysed the POINT-AGAPE microlensing event PA-99-N2, which shows an anomaly that according to our analysis reported in [2, 12] could be explained by a companion object of planetary mass orbiting the lens star. As rst, we tested the robustness of the binary lens conclusion for this light curve. Second, we showed that for such long duration and bright microlensing events, the eciency for nding planetary-like deviations is strongly enhanced with respect to that evaluated for all planetary detectable events [13], thus supporting further our conclusion reported in [2]. B.2 Dark matter in the central regions of early-type galaxies
Project leadership and contacts /
Projektleitung und Kontakte
Prof Philippe Jetzer (Project Leader)  
Dr Mauro Sereno  
Funding source(s) /
Unterstützt durch
Universität Zürich (position pursuing an academic career), Others
Duration of Project / Projektdauer Jan 2010 to Dec 2010