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Title: Galactic Bulge Microlensing Events from the MACHO Collaboration

Abstract

The authors present a catalog of 450 relatively high signal-to-noise microlensing events observed by the MACHO collaboration between 1993 and 1999. The events are distributed throughout the fields and, as expected, they show clear concentration toward the Galactic center. No optical depth is given for this sample since no blending efficiency calculation has been performed, and they find evidence for substantial blending. In a companion paper they give optical depths for the sub-sample of events on clump giant source stars, where blending is a less significant effect. Several events with sources that may belong to the Sagittarius dwarf galaxy are identified. For these events even relatively low dispersion spectra could suffice to classify these events as either consistent with Sagittarius membership or as non-Sagittarius sources. Several unusual events, such as microlensing of periodic variable source stars, binary lens events, and an event showing extended source effects are identified. They also identify a number of contaminating background events as cataclysmic variable stars.

Authors:
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Publication Date:
Research Org.:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
881074
Report Number(s):
UCRL-JRNL-213064
Journal ID: ISSN 0004-637X; ASJOAB; TRN: US200612%%777
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 631; Journal Issue: 2; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; EFFICIENCY; ERUPTIVE VARIABLE STARS; SPECTRA; STARS

Citation Formats

Thomas, C L, Griest, K, Popowski, P, Cook, K H, Drake, A J, Minniti, D, Myer, D G, Alcock, C, Allsman, R A, Alves, D R, Axelrod, T S, Becker, A C, Bennett, D P, Freeman, K C, Geha, M, Lehner, M J, Marshall, S L, Nelson, C A, Peterson, B A, Quinn, P J, Stubbs, C W, Sutherland, W, Vandehei, T, and Welch, D L. Galactic Bulge Microlensing Events from the MACHO Collaboration. United States: N. p., 2005. Web. doi:10.1086/432247.
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Thomas, C L, Griest, K, Popowski, P, Cook, K H, Drake, A J, Minniti, D, Myer, D G, Alcock, C, Allsman, R A, Alves, D R, Axelrod, T S, Becker, A C, Bennett, D P, Freeman, K C, Geha, M, Lehner, M J, Marshall, S L, Nelson, C A, Peterson, B A, Quinn, P J, Stubbs, C W, Sutherland, W, Vandehei, T, & Welch, D L. Galactic Bulge Microlensing Events from the MACHO Collaboration. United States. https://doi.org/10.1086/432247
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Thomas, C L, Griest, K, Popowski, P, Cook, K H, Drake, A J, Minniti, D, Myer, D G, Alcock, C, Allsman, R A, Alves, D R, Axelrod, T S, Becker, A C, Bennett, D P, Freeman, K C, Geha, M, Lehner, M J, Marshall, S L, Nelson, C A, Peterson, B A, Quinn, P J, Stubbs, C W, Sutherland, W, Vandehei, T, and Welch, D L. 2005. "Galactic Bulge Microlensing Events from the MACHO Collaboration". United States. https://doi.org/10.1086/432247. https://www.osti.gov/servlets/purl/881074.
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@article{osti_881074,
title = {Galactic Bulge Microlensing Events from the MACHO Collaboration},
author = {Thomas, C L and Griest, K and Popowski, P and Cook, K H and Drake, A J and Minniti, D and Myer, D G and Alcock, C and Allsman, R A and Alves, D R and Axelrod, T S and Becker, A C and Bennett, D P and Freeman, K C and Geha, M and Lehner, M J and Marshall, S L and Nelson, C A and Peterson, B A and Quinn, P J and Stubbs, C W and Sutherland, W and Vandehei, T and Welch, D L},
abstractNote = {The authors present a catalog of 450 relatively high signal-to-noise microlensing events observed by the MACHO collaboration between 1993 and 1999. The events are distributed throughout the fields and, as expected, they show clear concentration toward the Galactic center. No optical depth is given for this sample since no blending efficiency calculation has been performed, and they find evidence for substantial blending. In a companion paper they give optical depths for the sub-sample of events on clump giant source stars, where blending is a less significant effect. Several events with sources that may belong to the Sagittarius dwarf galaxy are identified. For these events even relatively low dispersion spectra could suffice to classify these events as either consistent with Sagittarius membership or as non-Sagittarius sources. Several unusual events, such as microlensing of periodic variable source stars, binary lens events, and an event showing extended source effects are identified. They also identify a number of contaminating background events as cataclysmic variable stars.},
doi = {10.1086/432247},
url = {https://www.osti.gov/biblio/881074}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 631,
place = {United States},
year = {Thu Jun 16 00:00:00 EDT 2005},
month = {Thu Jun 16 00:00:00 EDT 2005}
}
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https://doi.org/10.1086/432247
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