Radiation damping strongly perturbs remote resonances in presence of homo-nuclear mixing sequences

In this work, it is experimentally shown that the weak oscillating magnetic field (known as the “radiation damping” field) caused by the inductive coupling between the transverse magnetization of nuclei and the radio frequency circuit perturbs remote resonances when homo-nuclear total correlation mixing sequences are applied. Numerical simulations are used to rationalize this effect.

Mixing

The concepts of strong and uniform mixing are developed in the context of sequences of random variables. A set of important inequalities limiting the dependence of mixing sequences is proved. The case of linear processes is examined in depth including some well‐known counterexamples. Sufficient conditions are derived for strong and uniform mixing of linear processes.

Laws of large numbers for infinite means with mixing sequences

In this paper, we consider the laws of large numbers with infinite means based on ?-mixing sequences. An exact weak law and a strong law are obtained for ?-mixing asymmetrical Cauchy random variables. It is also presented that the weak law cannot extend to a strong law. In addition, some simulations are presented to illustrate our results of the laws of large numbers.

SkyMapper colours of Seyfert galaxies and Changing-Look AGN

ABSTRACT We study the utility of broad-band colours in the SkyMapper Southern Survey for selecting Seyfert galaxies at low luminosity. We find that the u − v index, built from the ultraviolet u and violet v filters, separates normal galaxies, starburst galaxies, and type-1 active galactic nuclei (AGNs). This u − v index is not sensitive to age or metallicity in a stellar population but is instead a quenching-and-bursting indicator in galaxies and detects power-law continua in type-1 AGNs. Using over 25 000 galaxies at z < 0.1 from 6dFGS, we find a selection cut based on u − v and central u band brightness that identifies type-1 AGNs. By eyeballing 6dFGS spectra we classify new Seyfert galaxies of type 1 to 1.8. Our sample includes eight known Changing-Look AGNs (CLAGNs), two of which show such strong variability that they move across the selection cut during the 5 yr of SkyMapper observations in DR3, along mixing sequences of nuclear and host galaxy light. We identify 46 CLAGN candidates in our sample, one of which has been reported as a Type IIn supernova. We show that this transient persists for at least 5 yr and marks a flare in a Seyfert-1 period of a new CLAGN.