Microlensing for non-experts Philip Yock 13th Microlensing Workshop Institut d'Astrophysique de Paris, January 19, 20, 21, 2009

January 2009 Cover story “Race to Find Alien Planets” Radial velocity, transits, Kepler - but nothing on microlensing!

Radial velocity and transit both conceptually simple How to present microlensing simply?

1. Create strong gravitational field

2. Qualitative picture  Einstein arcs slide around the ring when A max >> 1  If a low-mass planet is close to the ring, it perturbs the arc as it passes by  Width of perturbation equals ‘slide-by’ time  Height of perturbation  planet mass  Height of perturbation (roughly) independent of A max  Perturbations occur in the FWHM  24 hours

3. Demonstrate magnification maps

4. Teaching exercises Liebes theorem U min Masses of the lenses

5. Use magnification maps

Typical low resolution map

Typical medium resolution map

Typical high resolution map

Resolution adjustable Typical star size

Typical track of source star

Parallax corrections Andy Gould ApJ 606,

Parallaxed track

Beware the Moire effect! Shoot more rays

Summary Microlensing beautiful, but quite complicated Demonstrations possible Teaching exercises possible Magnification maps conceptually clear, versatile, if not fastest

Proof - test subjects Ian Bond, Christine Botzler, Sarah Holderness, Yvette Perrott, Lydia Phillpott, Nick Rattenbury, Sarah Schoen, Eike van Seggern, Petra Tang Ian Bond, Christine Botzler, Sarah Holderness, Yvette Perrott, Lydia Phillpott, Nick Rattenbury, Sarah Schoen, Eike van Seggern, Petra Tang

Proof - test subjects Ian Bond, Christine Botzler, Sarah Holderness, Yvette Perrott, Lydia Phillpott, Nick Rattenbury, Sarah Schoen, Eike van Seggern, Petra Tang Ian Bond, Christine Botzler, Sarah Holderness, Yvette Perrott, Lydia Phillpott, Nick Rattenbury, Sarah Schoen, Eike van Seggern, Petra Tang I couldn’t be happier

Petra Tang - MB07397 Chi 2 theta t 0

Eike van Seggern – MB02033 A&A 411, L493, , 645, 2005

Planet orbiting the binary lens?

Sarah Schoen Plasma wakefield acceleration New Scientist, Jan 2009 – “Desktop atom smashers could replace LHC” Analaogous to microlensing – uses naturally occurring fields – electromagnetic, not gravitational Analaogous to microlensing – uses naturally occurring fields – electromagnetic, not gravitational Could measure the charge of the quark Could measure the charge of the quark Could test multi-muons from Fermilab Could test multi-muons from Fermilab

40 GeV to 80 GeV, for $10, in one meter, riding a plasma wakefield Chan Joshi et al, Nature 445, (2007)

Invitation – January 2010 meeting Auckland, New Zealand

Conference centre

Auckland harbour

Race

Piha

Test plasma wakefield concept