Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · astro-ph/0102080

A Short Timescale Candidate Microlensing Event in the POINT-AGAPE Pixel Lensing Survey of M31

M. Auriere·P. Baillon·A. Bouquet·B. J. Carr·M. Creze·N. W. Evans·Y. Giraud-Heraud·A. Gould·P. Hewett·J. Kaplan·E. Kerins·E. Lastennet·Y. Le Du·A. -L. Melchior·S. Paulin-Henriksson·S. J. Smartt·D. Valls-Gabaud
View original source ↗Read source document ↗Export metadata ↓

Abstract

We report the discovery of a short-duration microlensing candidate in the northern field of the POINT-AGAPE pixel lensing survey towards M31. The full-width half-maximum timescale is very short, just 1.8 days. Almost certainly, the source star has been identified on Hubble Space Telescope archival images, allowing us to infer an Einstein crossing time of 10.4 days, a maximum magnification of about 18, and a lens-source proper motion greater than 0.3 microarcsec/day. The event lies projected at 8' from the center of M31, which is beyond the bulk of the stellar lens population. The lens is likely to reside in one of three locations. It may be a star in the M31 disk, or a massive compact halo object (Macho) in either M31 or the Milky Way. The most probable mass is 0.06 solar masses for an M31 Macho, 0.02 solar masses for a Milky Way Macho and 0.2 solar masses for an M31 stellar lens. Whilst the stellar interpretation is plausible, the Macho interpretation is the most probable for halo fractions above 20%.

Explore related subjects

astro-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

M. Auriere, P. Baillon, A. Bouquet, B. J. Carr, M. Creze, N. W. Evans, Y. Giraud-Heraud, A. Gould, P. Hewett, J. Kaplan, E. Kerins, E. Lastennet, Y. Le Du, A. -L. Melchior, S. Paulin-Henriksson, S. J. Smartt, D. Valls-Gabaud. 2001-02-05. A Short Timescale Candidate Microlensing Event in the POINT-AGAPE Pixel Lensing Survey of M31. https://doi.org/10.1086/320681

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Cosmic Conundrums with Quantum Corrections

Darh energy was discovered over 25 years ago and we do not have an explanation of it. Dark matter comprises 95% of matter in the universe and we still don't know what it is. The Webb telescope has been finding fully formed galaxies with massive black holes millions of times the mass of the sun in the early universe and we don't have any explanation. A quantum density limitation will be used to solve these and other outstanding problems.

astro-ph↗
arXiv2026

On binary pulsars and the force of gravity

The energy-momentum budget of the astrophysical systems can be studied by the exact local conservation equation derived by Landau and Lifshitz. We show that a similar equation is valid for the Einstein-Cartan gravity. We reanalyze a binary pulsar system using the Landau-Lifshitz conservation equation and show that the orbital period change rate can be completely understood as a curvature backreaction process. Taking into account the detailed theoretical and observational research of relativistic binary pulsar systems, especially the system of Hulse and Taylor, we conclude that general relativity and astrophysical observations rule out the existence of gravitational radiation. We comment upon the LIGO GW events and their alternative explanation, as well as the recent pulsar timing arrays data.

astro-ph↗
arXiv2026

Oscillation frequencies and mode lifetimes in alpha Centauri A

We analyse our recently-published velocity measurements of alpha Cen A (Butler et al. 2004). After adjusting the weights on a night-by-night basis in order to optimize the window function to minimize sidelobes, we extract 42 oscillation frequencies with l=0 to 3 and measure the large and small frequency separations. We give fitted relations to these frequencies that can be compared with theoretical models and conclude that the observed scatter about these fits is due to the finite lifetimes of the oscillation modes. We estimate the mode lifetimes to be 1-2 d, substantially shorter than in the Sun.

astro-ph↗