The history and physics of gravitational microlensing: its use to search for dark matter and planets. Talk for a general audience

1. Friday, February 13, 2009

2. Gravitational
Microlensing
David S. Graff Ph.D.
University of Michigan
Ohio State University
CEN Saclay, France
American Museum of Natural History
Friday, February 13, 2009

3. Friday, February 13, 2009

4. 2 survey of the Magellanic Clouds halo white dwarfs Sources and Detection of Dark Matter in the Universe, Not enough stellar mass Macho
aboration: P. Tisserand, L. Le Guillou The EROS collaboration: B. Goldman et al. Marina del Rey, CA, February 2000 The EROS collaboration: T. Las
Astronomy & Astrophysics 389 69 (2002) http://arxiv.org/abs/astro-ph/0007444 Astronomy & Astrophysics Letters 3
rophysics 469 387 (2007)
Observation of periodic variable stars towards the Type Ia supernova rate at z ~ 0.1 Death of Stellar Baryonic Dark
icrolensing Blending-Parallax Galactic spiral arms by EROS II The EROS collaboration: D. Hardin et al. Katherine Freese, Brian D. Field
g source variability The EROS collaboration: F. Derue et al. Astronomy & Astrophysics 362 419 (2000) Proceedings of “The First Stars”, M
aboration: R.J. Assef, A. Gould et al. Astronomy & Astrophysics 389 149 (2002) Aug. 4-6, 1999
l Journal: 649 954 (2006) Eros variable stars: A catalog of Cepheids in the http://arxiv.org/abs/astro-ph/000
Blue irregular variable stars in the Small Magellanic Magellanic Clouds
microlensing optical depth from Cloud from EROS2: The EROS collaboration: C. Afonso et al. Observation of Microlensing to
Herbig Ae/Be or classical Be stars? Astronomy & Astrophysics submitted astro-ph/9907355 Spiral Arms. EROS II 2 year sur
aboration: C. Hamadache et al. The EROS collaboration: J. P. Beaulieu et al. The EROS collaboration: F. De
rophysics: 454 185 (2006) Astronomy & Astrophysics 380 168 (2001) The velocity dispersion of LMC Carbon stars: Astronomy & Astrophysics 351 87 (
possible detection of a kinematically distinct
event 2c 2859: a classic nova outburst? Disk Contamination in a Sample of Proper Motion population Limits on Stellar Objects as the
aboration: C. Afonso et al. Selected Halo Stars: David Graff, Andrew Gould, Nicholas Suntzeff, Halo:
rophysics: 450 233 (2006) A Comment on “Direct Detection of Galactic Halo Robert Schommer, and Eduardo Hardy Nonbaryonic Dark Matter Seem
Dark Matter” Astrophysical Journal 540 211 (2000) Katherine Freese, Brian Fields,
etry of probable R Coronae Borealis David S. Graff Proceedings of the 19th Texas Sympo
ll Magellanic Cloud Science 292 2211 (2001) Detection of light from Giant Planets in the Galactic Astrophysics and Cosmology
aboration: P. Tisserand et al. Bulge http://arxiv.org/abs/astro-ph/990
rophysics 424 245 (2004) Photometric constraints on microlens spectroscopy Amplified by caustic-crossing microlensing events
of EROS-BLG-2000-5 David S. Graff and B. Scott Gaudi EROS 2 proper motion survey:
va rate at a redshift of z~0.1 The EROS collaboration: C. Afonso et al. Astrophysical Journal Letters 538 133 (2000) and an L dwarf companion to L
aboration: G. Blanc et al. Astronomy & Astrophysics 378 1014 (2001) The EROS collaboration: B. Go
rophysics 423 881 (2004) What are MACHOs? Interpreting LMC Astronomy & Astrophysics 351 5 (1
Observation of Microlensing towards the Galactic microlensing
upermassive Black Holes in Galactic Spiral Arms. EROS II 3 year survey David S. Graff Constraining the Cosmic Abund
The EROS collaboration: F. Derue et al. Microlensing 2000: A New Era of Microlensing Astrophysics Remnants with Multi-TeV Gam
lapse Model Consistent with the MBH- Astronomy & Astrophysics 373 126 (2001) ASP conference proceedings, eds. J.W. Menzies and David S. Graff, Katherine Frees
P.D. Sackett Marc H. Pinsonneault
No Nearby Counterparts to the moving objects in http://arxiv.org/abs/astro-ph/0005521 Astrophysical Journal 523 77 (1999
David S. Graff, Mannase Mbonye &
the Hubble Deep Field
hstone
Chris Flynn, J. Sommer-Larsen, Burkhard Fuchs, Chemical Abundance Constraints on White Dwarfs Microlensing in the SMC: Lesso
l Journal 591 125 (2003)
David S. Graff and Samir Salim as Halo Dark Matter simulations
Monthly Notices of the Royal Astronomical Society 322 533 Brian D. Fields, Katherine Freese, and David S. Graff David S. Graff and Lance Gardi
sing optical depth from EROS 2
(2001) Astrophysical Journal 534 265 (2000) Monthly Notices of the Royal Astro
(1999)
aboration: C. Afonso et al.
Using the Supernova Acceleration Probe (SNAP) High Velocity Star Formation in the LMC
rophysics 404 145 (2003)
to Search for Microlensing Events Towards the LMC David S. Graff and Andrew Gould A Slope Variation in the Period-
David S. Graff and Alex Kim Astrophysical Journal Letters 534 51 (2000) for Short Period SMC Cepheids
f Stars via Microlensing
http://arxiv.org/abs/astro-ph/0101395 The EROS collaboration: F. Bau
Cheongho Han & David S. Graff
Combined Analysis of the Binary-Lens Caustic- Astronomy & Astrophysics 348 175
l Journal 586 451 (2003)
A Theoretical Model for the MBH- Relation for Crossing Event MACHO 98-SMC-1
Supermassive Black Holes in Galaxies The EROS, MACHO/GMAN, MPS, OGLE, and Microlensing towards the Small
tic dark matter with 5 years of EROS
Fred C. Adams, David S. Graff, and Douglas O. PLANET Collaborations EROS II two year analysis
Richstone C. Afonso et al., C. Alcock et al., S.H. Rhie et al., A. The EROS collaboration: C. Af
aboration: C. Afonso et al
Astrophysical Journal 551 31 (2001) Udalski et al., M. Albrow et al. Astronomy & Astrophysics 344 63
rophysics 400 951 (2002)
Astrophysical Journal 532 340 (2000)
The Kinematics Of The LMC From Its Carbon Stars What are Machos? Limits on St
llaxes of Binary Lenses Measured from
E. Hardy, D. Alves, D. Graff, N. Suntzeff, and R. Magnitude bias of microlensed sources towards the Dark Matter of our Halo
Schommer Large Magellanic Cloud Katherine Freese, Brian Fields,
Andrew P. Gould
Astrophysics and Space Science Supplement 277 271 (2001) HongSheng Zhao, David Graff, and Puragra Proceedings of the International Wo
l Journal 580 253 (2002)
Guhathakurta Dark Matter in Astro andParticle P
Death of Stellar Baryonic Dark Matter Candidates Astrophysical Journal 532 37 (2000) Germany, July 1998
Friday, February 13, 2009

5. Lensing Physics Dark Matter Microlensing & Microlensing
Dark Matter & Planets
Friday, February 13, 2009

6. Lensing Physics Dark Matter Microlensing & Microlensing
Dark Matter & Planets
Friday, February 13, 2009

7. Lensing Physics Dark Matter Microlensing & Microlensing
Dark Matter & Planets
Friday, February 13, 2009

8. Lensing Physics Dark Matter Microlensing & Microlensing
Dark Matter & Planets
Friday, February 13, 2009

9. AB will perceive, instead of a point-like star A, a to the expression
x2
luminius circle of the angular radius @ around the 1 -!-
I
center of B, where q=-.- 21
where
6
I t should be noted that this angular diameter does