SKA Science Measuring Variations in the Measuring Variations in the Fundamental Constants with Fundamental Constants with the SKA the SKA Steve Curran Steve Curran School of Physics School of Physics University of New South University of New South Wales Wales
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SKA Science Measuring Variations in the Fundamental Constants with the SKA Steve Curran School of Physics School of Physics University of New South Wales.
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SKA Science
Measuring Variations in the Measuring Variations in the Fundamental Constants with Fundamental Constants with
the SKAthe SKA
Steve CurranSteve Curran School of PhysicsSchool of Physics
University of New South University of New South WalesWales
SKA Science
To Earth
Heavy element absorption
Emission lines from the Quasar
Lyman limit
Hydrogen absorption due to galaxy
Quasar
Observed wavelength (Å)Lyman alpha forest
DLA
SKA Science
MotivationMotivation
Optical studies (Optical studies (Webb et al. 2002, Webb et al. 2002,
astro-ph/0210531astro-ph/0210531) suggest that) suggest that
= -0.57(0.10) x 10-5 for 0.2< zabs < 3.7
Although Although Chand et al. 2004 Chand et al. 2004 (astro-ph/0401094(astro-ph/0401094) find no change over 0.4< ) find no change over 0.4<
zzabsabs < 2.3 < 2.3
SKA Science
Advantage of Radio LinesAdvantage of Radio Lines
21-cm Spin-Flip (HI) Line Transition Interaction of electron and proton magnetic fields
21 is proportional to 2 gp
That is, comparing radio and optical gives anThat is, comparing radio and optical gives anorder of magnitude the sensitivity of the purely order of magnitude the sensitivity of the purely
optical comparisons.optical comparisons.See See Drinkwater et al., 1998, MNRAS 295, 457.Drinkwater et al., 1998, MNRAS 295, 457.
Optical Transitions Interaction is Coulombic, so
opt is proportional to (1 + 0.032 )(Flambaum & Dzuba)
SKA Science
Furthermore, using molecular lines…Furthermore, using molecular lines…