310 likes | 481 Views
Microlensing for non-experts. 13th Microlensing Workshop Institut d'Astrophysique de Paris, January 19, 20, 21, 2009. Philip Yock. January 2009 Cover story. “Race to Find Alien Planets”. Radial velocity, transits, Kepler - but nothing on microlensing!.
E N D
Microlensing for non-experts 13th Microlensing Workshop Institut d'Astrophysique de Paris, January 19, 20, 21, 2009 Philip Yock
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?
2. Qualitative picture • Einstein arcs slide around the ring when Amax >> 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 Amax • Perturbations occur in the FWHM 24 hours
4. Teaching exercises Liebes theorem Umin Masses of the lenses
Resolution adjustable Typical star size
Parallax corrections Andy Gould ApJ 606, 319 2004
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
Proof - test subjects 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 Chi2 theta t0
Eike van Seggern – MB02033 A&A 411, L493, 2003 439, 645 , 2005
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 • Could measure the charge of the quark • 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, 741-744 (2007)
Invitation – January2010 meeting Auckland,New Zealand