Fast Radio Bursts from Extragalactic Light Sails

Manasvi Lingam, Abraham Loeb
We examine the possibility that Fast Radio Bursts (FRBs) originate from the activity of extragalactic civilizations.
Our analysis shows that beams used for powering large light sails could yield parameters that are consistent with FRBs.
The characteristic diameter of the beam emitter is estimated through a combination of energetic and engineering constraints, and both approaches intriguingly yield a similar result which is on the scale of a large rocky planet.
Moreover, the optimal frequency for powering the light sail is shown to be similar to the detected FRB frequencies. These `coincidences’ lend some credence to the possibility that FRBs might be artificial in origin.
Other relevant quantities, such as the characteristic mass of the light sail, and the angular velocity of the beam, are also derived.
By using the FRB occurrence rate, we infer upper bounds on the rate of FRBs from extragalactic civilizations in a typical galaxy.
The possibility of detecting fainter signals is briefly discussed, and the wait time for an exceptionally bright FRB event in the Milky Way is estimated.
Read more at https://arxiv.org/pdf/1701.01109.pdf

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Cosmic Neutrinos Detected, Confirming The Big Bang’s Last Great Prediction

The fit of the number of neutrino species required to match the CMB fluctuation data. Image credit: Brent Follin, Lloyd Knox, Marius Millea, and Zhen PanPhys. Rev. Lett. 115, 091301 — Published 26 August 2015.

The fit of the number of neutrino species required to match the CMB fluctuation data. Image credit: Brent Follin, Lloyd Knox, Marius Millea, and Zhen PanPhys. Rev. Lett. 115, 091301 — Published 26 August 2015.

(…) Last year, a paper by Brent Follin, Lloyd Knox, Marius Millea and Zhen Pan came out, detecting this phase shift for the first time. From the publicly-available Planck (2013) data, they were able to not only definitively detect it, they were able to use that data to confirm that there are three types of neutrinos — the electron, muon and tau species — in the Universe: no more, no less.

The number of neutrino species as inferred by the CMB fluctuation data. Image credit: Brent Follin, Lloyd Knox, Marius Millea, and Zhen PanPhys. Rev. Lett. 115, 091301 — Published 26 August 2015.

The number of neutrino species as inferred by the CMB fluctuation data. Image credit: Brent Follin, Lloyd Knox, Marius Millea, and Zhen PanPhys. Rev. Lett. 115, 091301 — Published 26 August 2015.

What’s incredible about this is that there is a phase shift seen, and that when the Planck polarization spectra came out and become publicly available, they not only constrained the phase shift even further, but — as announced by Planck scientists in the aftermath of this year’s AAS meeting — they finally allowed us to determine what the temperature is of this Cosmic Neutrino Background today! (Or what it would be, if neutrinos were massless.) The result? 1.96 K, with an uncertainty of less than ±0.02 K. This neutrino background is definitely there; the fluctuation data tells us this must be so. It definitely has the effects we know it must have; this phase shift is a brand new find, detected for the very first time in 2015. Combined with everything else we know, we have enough to state that yes, there are three relic neutrino species left over from the Big Bang, with the kinetic energy that’s exactly in line with what the Big Bang predicts.(…)

Read more at http://www.forbes.com/sites/startswithabang/2016/09/09/cosmic-neutrinos-detected-confirming-the-big-bangs-last-great-prediction/#66a2193b4be4

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How supernovae became the basis of observational cosmology

Supernova classification

Supernova classification

Maria Victorovna Pruzhinskaya, Sergey Mikhailovich Lisakov
This paper is dedicated to the discovery of one of the most important relationships in supernova cosmology – the relation between the peak luminosity of Type Ia supernovae and their luminosity decline rate after maximum light.
The history of this relationship is quite long and interesting. The relationship was independently discovered by the American statistician and astronomer Bert Woodard Rust and the Soviet astronomer Yury Pavlovich Pskovskii in the 1970s.
Using a limited sample of Type I supernovae they were able to show that the brighter the supernova is, the slower its luminosity declines after maximum.
Only with the appearance of CCD cameras could Mark Phillips re-inspect this relationship on a new level of accuracy using a better sample of supernovae. His investigations confirmed the idea proposed earlier by Rust and Pskovskii.
Read more at https://arxiv.org/ftp/arxiv/papers/1608/1608.04192.pdf

KIC 8462852 Faded Throughout the Kepler Mission

Over the four years that the Kepler telescope monitored this mysterious star, its light levels dropped by a total of about 3 percent--but not all at a constant rate. (For reference, the huge dip at the 800 mark is one of the huge dips that originally tipped off scientists that this was a freakin' weird star. "It was off the charts," says Montet.)

Over the four years that the Kepler telescope monitored this mysterious star, its light levels dropped by a total of about 3 percent–but not all at a constant rate. (For reference, the huge dip at the 800 mark is one of the huge dips that originally tipped off scientists that this was a freakin’ weird star. “It was off the charts,” says Montet.)

Benjamin T. Montet, Joshua D. Simon
KIC 8462852 is a superficially ordinary main sequence F star for which Kepler detected an unusual series of brief dimming events. We obtain accurate relative photometry of KIC 8462852 from the Kepler full frame images, finding that the brightness of KIC 8462852 monotonically decreased over the four years it was observed by Kepler. Over the first ~1000 days, KIC 8462852 faded approximately linearly at a rate of 0.341 +/- 0.041 percent per year, for a total decline of 0.9%. KIC 8462852 then dimmed much more rapidly in the next ~200 days, with its flux dropping by more than 2%. For the final ~200 days of Kepler photometry the magnitude remained approximately constant, although the data are also consistent with the decline rate measured for the first 2.7 yr. Of a sample of 193 nearby comparison stars and 355 stars with similar stellar parameters, 0.6% change brightness at a rate as fast as 0.341 +/- 0.041 percent per year, and none exhibit either the rapid decline by >2% or the cumulative fading by 3% of KIC 8462852. We examine whether the rapid decline could be caused by a cloud of transiting circumstellar material, finding while such a cloud could evade detection in sub-mm observations, the transit ingress and duration cannot be explained by a simple cloud model. Moreover, this model cannot account for the observed longer-term dimming. No known or proposed stellar phenomena can fully explain all aspects of the observed light curve.

Read more at https://arxiv.org/pdf/1608.01316v1.pdf
Read also: SCIENTISTS IN THE DARK OVER YEARS-LONG DIMMING OF ‘ALIEN MEGASTRUCTURE STAR’