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Modelling Microlensing Events Workshop

Submitted by rachelstreet on 21 August 2008 - 10:21pm.

"Fitting anomalous microlensing events - approaches and time constraints"

 

Date: November 10 - 13 2008

  • The day-by-day program of the workshop will be announced at a later date.
  • Registration Deadline: Oct 5 2008

We urge you to register as soon as possible to facilitate organization of the
meeting. To register, please email Yiannis Tsapras (ytsapras) or Rachel Street (rstreet) by adding these usernames to the email address @lcogt.net.

 

Dear microlensers,

 

This is the first announcement of the LCOGT microlensing workshop on programming practices for fitting anomalous microlensing events.

The microlensing method has come of age in the last few years with several confirmed detections of planets but modelling the most intriguing events is still a very time consuming process that requires significant human and computing resources. As a result, the majority of binary events each season go unmodelled. With existing facilities being upgraded and new ones being commissioned, as well as more powerful campaigns in the planning, the gap between data acquisition and analysis is only going to increase.

At this meeting, we would like to review the state of the art of all modules that are required for turning a microlensing data set into a probabilistic assessment of the nature of the underlying physical system, figure out what parts are missing and discuss ways of closing the gap between where we stand now and what we would like to achieve.

The workshop will last for 4 days and comprise a series of informal presentations focused on key topics in microlensing modelling, from the different methods used to approach the lensing equations, multi-site data rescaling, parameter space search efficiency and how to deal with multiple solutions. These presentations will be given by leading experts in the field and attendees will have the chance to see demonstrations of the various codes in operation. There will be ample time left for questions and open discussions.

Specific subtopics:
  1. Calibrating the data from multiple sites
    • reported error bars, flux<->magnitudes conversions per site, common data format
    • error bar rescaling
    • observing responses to outliers (site specific)
    • observing conditions data
    • Image subtraction & data reduction
    • synchronising data sharing
  2. Model parameterization
    • modelling ordinary lightcurves and anomalies
    • model ambiguities and parameter degeneracies
    • dealing with data gaps
    • selecting initial conditions
  3. Magnification-vs-time
    • binary lenses
      • point source
      • resolved source
    • blending
    • binary source
    • parallax
    • rotating binary
    • triple lenses or more
  4. Parameter space search to best models
    • event libraries & pattern recognition
    • division of parameter space to subspaces
    • artificial neural networks
    • genetic algorithms
    • Markov Chain Monte Carlo
    • local minima: identification of multiple solutions and arriving at the "best" solution
    • Model optimization
      • chi^2 minimization: downhill simplex, gradients
      • other algorithms
  5. Probabilistic interpretation
    • from successful fits to real physical parameters
    • assessing the confidence of parameter estimation
  6. Cooperation and efficient communication
    • common data exchange file format
    • transfer of active data between observing campaigns
    • development of web-based tools
    • data visualization
    • communicating with the media & public (?)
  7. LCOGT
    • status of 2m
    • deployment of 1m telescopes
    • expectations of the microlensing community from LCOGT
    • LCOGT involvement in microlensing searches

 


The workshop will be held in Santa Barbara, California, close to the LCOGT headquarters at Las Cumbres Observatory, 6740 Cortona Dr. Suite 102, Santa Barbara, CA 93117, USA.

If you would like to contribute a presentation at this workshop please contact ytsapras(at)lcogt.net and send the title and a brief description. Given the time constraints, we cannot guarantee that it will be included in the final programme but all submissions will be considered.

Unfortunately we have no funds to pay for travel or accommodation. Due to the informal nature of this workshop, no registration fee is necessary. Unless you wish to make your own bookings, LCOGT will handle accommodation arrangements once the list of participants is finalized.

Information on travel and accomodation in our area is available here.

If you cannot make it to St barbara on those dates, there is also the option to participate via videocon. Please contact rstreet(at)lcogt.net for more information.

 

On behalf of LCOGT,
Yiannis Tsapras & Rachel Street