The OGLE View of Microlensing towards the Magellanic Clouds. I. A Trickle of Events in the OGLE-II LMC data - Astrophysics > Astrophysics of GalaxiesReportar como inadecuado




The OGLE View of Microlensing towards the Magellanic Clouds. I. A Trickle of Events in the OGLE-II LMC data - Astrophysics > Astrophysics of Galaxies - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: We present the results from the OGLE-II survey 1996-2000 towards the LargeMagellanic Cloud LMC, which has the aim of detecting the microlensingphenomena caused by dark matter compact objects in the Galactic Halo Machos.We use high resolution HST images of the OGLE fields and derive thecorrection for the number of monitored stars in each field. This also yieldblending distributions which we use in -catalogue level- Monte Carlosimulations of the microlensing events in order to calculate the detectionefficiency of the events.We detect two candidates for microlensing events in the All Stars Sample,which translates into an optical depth of 0.43+-0.33x 10e-7. If both eventswere due to Macho the fraction of mass of compact dark matter objects in theGalactic halo would be 8+-6 per cent. This optical depth, however, along withthe characteristics of the events, seems to be consistent with the self-lensingscenario, i.e., self-lensing alone is sufficient to explain the observedmicrolensing signal. Our results indicate a non-detection of Machos lensingtowards the LMC with an upper limit on their abundance in the Galactic halo of19 per cent for M=0.4 Msun and 10 per cent for masses between 0.01 and 0.2Msun.



Autor: L. Wyrzykowski, S. Kozlowski, J. Skowron, V. Belokurov, M. C. Smith, A. Udalski, M. K. Szymanski, M. Kubiak, G. Pietrzynski, I. S

Fuente: https://arxiv.org/



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