Year: 2010
Type: article
Abstract: We present an updated analysis of the M31 pixel lensing candidate event OAB-N2 previously reported by Calchi Novati et al. Here we take advantage of new data both astrometrical and photometrical. For astrometry: using archival 4 m KPNO and Hubble Space Telescope /WFPC2 data we perform a detailed analysis of the event source whose result, although not fully conclusive on the source magnitude determination, is confirmed by the following light curve photometry analysis. For photometry: first, unpublished WeCAPP data allow us to confirm OAB-N2, previously reported only as a viable candidate, as a well-constrained pixel lensing event. Second, this photometry enables a detailed analysis in the event parameter space including the effects due to a finite source size. The combined results of these analyses allow us to put a strong lower limit on the lens proper motion. This outcome favors the MACHO lensing hypothesis over self-lensing for this individual event and points the way toward distinguishing between the MACHO and self-lensing hypotheses from larger data sets.
Source: The Astrophysical Journal
Institutions: University of Salerno, Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, International Institute for Advanced Scientific Studies "Eduardo R. Caianiello", National Institute for Astrophysics, The Ohio State University, University of Salento, Istituto Nazionale di Fisica Nucleare, Sezione di Lecce, University of St Andrews, University of Zurich, Institute for Theoretical Physics, University of Sannio, European Space Astronomy Centre, Politecnico di Torino, Istituto Nazionale di Fisica Nucleare, Sezione di Torino
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W1967606268