Using variability and VLBI to measure cosmological distances

Abstract

In this paper, we propose a new approach to determining cosmological distances to active galactic nuclei (AGN) via light travel-time arguments, which can be extended from nearby sources to very high redshift sources. The key assumption is that the variability seen in AGN is constrained by the speed of light and therefore provides an estimate of the linear size of an emitting region. This can then be compared with the angular size measured with very long baseline interferometry (VLBI) in order to derive a distance. We demonstrate this approach on a specific well studied low redshift (z = 0.0178) source 3C84 (NGC 1275), which is the bright radio core of the Perseus Cluster. We derive an angular diameter distance including statistical errors of $D_A=72_{-6}^{+5}$ Mpc for this source, which is consistent with other distance measurements at this redshift. Possible sources of systematic errors and ways to correct for them are discussed.

Accepted for publication in MNRAS Letters, 5 pages, 2 figures, 1 table

References in corpus (11)

• A luminous quasar at a redshift of z = 7.085
• Improved Dark Energy Constraints from ~100 New CfA Supernova Type Ia Light Curves
• Doppler factors, Lorentz factors and viewing angles for quasars, BL Lacertae objects and radio galaxies
• Kinematics of Parsec-Scale Jets of Gamma-Ray Blazars at 43~GHz within the VLBA-BU-BLAZAR Program
• A Parallax Distance to the Microquasar GRS 1915+105 and a Revised Estimate of its Black Hole Mass
• A general test of the Copernican Principle
• Kinematics of the Local Universe XIII. 21-cm line measurements of 452 galaxies with the Nançay radiotelescope, JHK Tully-Fisher relation and preliminary maps of the peculiar velocity field
• Strong Lens Time Delay Challenge: II. Results of TDC1
• Ultra-compact structure in intermediate-luminosity radio quasars: building a sample of standard cosmological rulers and improving the dark energy constraints up to $z\sim 3$
• New observational constraints on $f(T)$ cosmology from radio quasars
• Multiple measurements of quasars acing as standard probes: exploring the cosmic distance duality relation at higher redshift

Cited by in corpus (6)

• Cosmology Intertwined: A Review of the Particle Physics, Astrophysics, and Cosmology Associated with the Cosmological Tensions and Anomalies
• A detailed kinematic study of 3C 84 and its connection to Gamma-rays
• Interferometric Monitoring of Gamma-ray Bright AGNs: Measuring the Magnetic Field Strength of 4C +29.45
• Estimating the feasibility of `standard speed-gun' distances
• Detection of an orthogonal alignment between parsec scale AGN jets and their host galaxies
• Distance Duality Test: The Evolution of Radio Sources Mimics a Nonexpanding Universe