Radio-flaring Ultracool Dwarf Population Synthesis

TL;DR

This paper develops a Monte Carlo simulation to estimate the population of radio-flaring ultracool dwarfs within 25 parsecs, revealing that only about 5% have been discovered, and explores factors affecting this detection rate.

Contribution

It introduces the first Monte Carlo simulator for radio-flaring ultracool dwarfs using advanced random number generation technology, providing new insights into their population and detection fraction.

Findings

Approximately 5% of local radio-flaring UCDs are detected.

The simulator suggests many UCDs remain undiscovered.

ISK random generator performs well for astrophysical simulations.

Abstract

Over a dozen ultracool dwarfs (UCDs), low-mass objects of spectral types $\geq$M7, are known to be sources of radio flares. These typically several-minutes-long radio bursts can be up to 100\% circularly polarized and have high brightness temperatures, consistent with coherent emission via the electron cyclotron maser operating in $\sim$kG magnetic fields. Recently, the statistical properties of the bulk physical parameters that describe these UCDs have become adequately described to permit synthesis of the population of radio-flaring objects. For the first time, I construct a Monte Carlo simulator to model the population of these radio-flaring UCDs. This simulator is powered by Intel Secure Key (ISK)- a new processor technology that uses a local entropy source to improve random number generation that has heretofore been used to improve cryptography. The results from this simulator indicate that only $\sim$5% of radio-flaring UCDs within the local interstellar neighborhood ($<$25 pc away) have been discovered. I discuss a number of scenarios which may explain this radio-flaring fraction, and suggest that the observed behavior is likely a result of several factors. The performance of ISK as compared to other pseudorandom number generators is also evaluated, and its potential utility for other astrophysical codes briefly described.