The Instantaneous Redshift Difference of Gravitationally Lensed Images: Theory and Observational Prospects

Abstract

Due to the expansion of our Universe, the redshift of distant objects changes with time. Although the amplitude of this redshift drift is small, it will be measurable with a decade-long campaigns on the next generation of telescopes. Here we present an alternative view of the redshift drift which captures the expansion of the universe in single epoch observations of the multiple images of gravitationally lensed sources. Considering a sufficiently massive lens, with an associated time delay of order decades, simultaneous photons arriving at a detector would have been emitted decades earlier in one image compared to another, leading to an instantaneous redshift difference between the images. We also investigate the effect of peculiar velocities on the redshift difference in the observed images. Whilst still requiring the observational power of the next generation of telescopes and instruments, the advantage of such a single epoch detection over other redshift drift measurements is that it will be less susceptible to systematic effects that result from requiring instrument stability over decade-long campaigns.

6 pages, 5 figures

References in corpus (14)

• Cosmic dynamics in the era of Extremely Large Telescopes
• The acceleration of the universe and the physics behind it
• Exploring the Dark Energy Redshift Desert with the Sandage-Loeb Test
• The time evolution of cosmological redshift as a test of dark energy
• Time drift of cosmological redshifts and its variance
• Redshift propagation equations in the ${\beta }^{\prime }\ne 0$ Szekeres models
• Exploring holographic dark energy model with Sandage-Loeb test
• The ACCELERATION programme: I. Cosmology with the redshift drift
• Testing the LCDM model (and more) with the time evolution of the redshift
• Peculiar acceleration
• Exploring the Redshift-Space Peculiar Velocity Field and its Power Spectrum
• Toward a direct measurement of the cosmic acceleration: the first preparation with FAST
• A new Einstein Cross gravitational lens of a Lyman-break galaxy
• A Measurement of the Cosmic Expansion Within our Lifetime

Cited by in corpus (2)

• Testing CCC+TL Cosmology with Observed BAO Features
• Constraining minimally extended varying speed of light by cosmological chronometers