Electromagnetic Polarization Effects due to Axion Photon Mixing

We investigate the effect of axions on the polarization of electromagnetic waves as they propagate through astronomical distances. We analyze the change in the dispersion of the electromagnetic wave due to its mixing with axions. We find that this leads to a shift in polarization and turns out to be the dominant effect for a wide range of frequencies. We analyze whether this effect or the decay of photons into axions can explain the large scale anisotropies which have been observed in the polarizations of quasars and radio galaxies. We also comment on the possibility that the axion-photon mixing can explain the dimming of distant supernovae.Comment: 18 pages, 1 figur

A complete 3D numerical study of the effects of pseudoscalar-photon mixing on quasar polarizations

We present the results of three-dimensional simulations of quasar polarizations in the presence of pseudoscalar-photon mixing in the intergalactic medium. The intergalactic magnetic field is assumed to be uncorrelated in wave vector space but correlated in real space. Such a field may be obtained if its origin is primordial. Furthermore we assume that the quasars, located at cosmological distances, have negligible initial polarization. In the presence of pseudoscalar-photon mixing we show, through a direct comparison with observations, that this may explain the observed large scale alignments in quasar polarizations within the framework of big bang cosmology. We find that the simulation results give a reasonably good fit to the observed data.Comment: 15 pages, 8 figures, significant changes, to appear in EPJ

Temporal patterns of pollen shedding for longleaf pine (Pinus palustris) at the Escambia Experimental Forest in Alabama, USA

Longleaf pine is an important tree species in the southeastern United States and studying the temporal patterns of pollen shedding is crucial to a better understanding of its phenology and seed production. In this study, field observation data on the timing of pollen shedding from 1958 to 2013 were analyzed with reference to local weather conditions. Our results indicated that the time of peak pollen shedding after January 1 (TPPS) ranged from 53 days (about February 22) to 95 days (around April 5). There was no significant trend of decreasing TPPS. The number of days with the maximum air temperature above 0 °C was close to the TPPS. The accumulated maximum daily air temperature for the TPPS approximated an average of 1,342 °C. The TPPS declined with an increase in the average air temperature during winters. The time of 80% accumulated pollen density (TAPD) varied from 5 to 32 days, with an average of 13 days. Taylor’s power-law was evident in the TAPD data, with the time group of 10–15 days having an interval time of 2 years. Winter weather was not correlated with the TAPD. These results provide new information concerning the pollen phenology for longleaf pine tree