Macho Light Curve Analysis

                   

Principal Investigator

Tim Axelrod

Mount Stromlo and Siding Spring Observatories

The Macho Project is searching for baryonic darkmatter in the halo of the Galaxy using gravitational
microlensing. In the first two years of the project we detected a large number of microlensing events toward the Galactic bulge and the Large Magellanic Cloud (LMC). Analysis of these events indicates that roughly half of the dark matter in the halo is in the form of baryonic objects with masses a few tenths of a solar mass. We are now focussed on analyzing our full data set, which consists of over five years of data from the bulge, the LMC, and the Small Magellanic Cloud (SMC).
   

Co-Investigators

     

Jon Smillie

Mount Stromlo and Siding Spring Observatories

     
                 

Projects

w01 - PC


     
                 
                   

What are the results to date and the future of this work?

After converting our analysis codes to run on the PC, we have utilised them to analyze our full SMC data set, and four years worth of LMC data. Analysis of the remaining bulge data is underway. The four year LMC analysis is complete and is being written up for publication. In the process of analyzing the SMC data, the world's first microlensing event toward the SMC was discovered. This work has been accepted for publication in Astrophysical Journal.

What computational techniques are used?

We use a time series analysis package written within the project for this specific purpose. After making some cuts on the raw data, a bank of matched filters are applied to look for possible variable sources. Sources found to be variable are fit to microlensing models for further analysis.

The code is written in C and is extensively vectorized by the PC optimizing compilers.

Publications

C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod, A. C. Becker, D. P. Bennett, K. H. Cook, K. C. Freeman, K. Griest, M. J. Lehner, S. L. Marshall, D. Minniti, B. A. Peterson, M. R. Pratt, P. J. Quinn, A. W. Rodgers, C. W. Stubbs, W. Sutherland, A. Tomaney, T. Vandehei, and D. L. Welch (The MACHO Collaboration) Is the Large Magellanic Cloud Microlensing Due to an Intervening Dwarf Galaxy? ApJ 490, 59 (1997).

   
                   
- ANU Supercomputer Facility Annual Report 1997 - Appendix A
 

 
                   

       

C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod, A. C. Becker, D. P. Bennett, K. H. Cook, K.C. Freeman, K. Griest, J. Guern, M. J. Lehner, S. L. Marshall, D. Minniti, B. A. Peterson, M. R. Pratt, P. J. Quinn, A.W. Rodgers, W. Sutherland, and D. L. Welch(The MACHO Collaboration) The MACHO Project, Large Magellanic Cloud Variable Star Inventory. III. Multimode RR Lyrae Stars, Distance to the Large Magellanic Cloud, and Age of the Oldest Stars, ApJ, 482, 89 (1997).

C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod, A.C. Becker, D. P. Bennett, P. A. Charles, K. H. Cook, K.C. Freeman, K. Griest, J. Guern, M. J. Lehner, M. Livio, S. L. Marshall, B. A. Peterson, M. R. Pratt, P. J. Quinn, A. W. Rodgers, K. A. Southwell, C.W. Stubbs, and W. Sutherland (The MACHO Collaboration), The X-ray off-state of the supersoft source CAL 83 and its interpretation, MNRAS, 286, 483 (1997).

C. Alcock, R. A. Allsman, D. Alves, T. S. Axelrod, D. P. Bennett, K. H. Cook, K. C. Freeman, K. Griest, J. Guern, M. J. Lehner, S. L. Marshall, H. S. Park, S. Perlmutter, B. A. Peterson, M. R. Pratt, P. J. Quinn, A. W. Rodgers, C. W. Stubbs, and W. Sutherland (The MACHO Collaboration), The MACHO Project: 45 Candidate Microlensing Events from the First-Year Galactic Bulge Data, ApJ, 479, 119 (1997).

C. Alcock, R. A. Allsman, D. Alves, T. S. Axelrod, D. P. Bennett, P. A. Charles, K. H. Cook, D. O'Donoghue, K. C. Freeman, K. Griest, J. Guern, M. J. Lehner, M. Livio, S. L. Marshall, D. Minniti, B. A. Peterson, M. R. Pratt, P. J. Quinn, A. W. Rodgers, K. A. Southwell, C. W. Stubbs, W. Sutherland and D. L. Welch (The MACHO Collaboration) Optical photometry of the eclipsing Large Magellanic Cloud supersoft source CAL 87, MNRAS, 287, 699 (1997).

C. Alcock, R. A. Allsman, D. Alves, T. S. Axelrod, A.C. Becker, D. P. Bennett, K. H. Cook, K. C. Freeman, K. Griest, J. Guern, M. J. Lehner, S. L. Marshall, D. Minniti, B. A. Peterson, M.R. Pratt, P. J. Quinn, A. W. Rodgers, C. W. Stubbs, W. Sutherland and D. L. Welch, (The MACHO Collaboration), MACHO Project Photometry of RR Lyrae Stars in the Sagittarius Dwarf Galaxy, ApJ, 474, 217 (1997)

       
ANU Supercomputer Facility Annual Report 1997 Appendix A -