# gst: apropos of vanishing, strange behaviors, 'sometimes they are there, and then for very long periods of time, they are not.'

AA << report the discovery of two long-term intermittent radio pulsars in the ongoing Pulsar Arecibo L-Band Feed Array survey. >>

<<  PSRs J1910+0517 and J1929+1357 show long-term extreme bimodal intermittency, switching between active (ON) and inactive (OFF) emission states and indicating the presence of a large, hitherto unrecognized underlying population of such objects. >>

<< This is the first time that a significant evolution in the activity of an intermittent pulsar has been seen, and we show that the spin-down rate of the pulsar is proportional to the activity. >>

Lyne AG,  Stappers BW, et al. Two Long-Term Intermittent Pulsars Discovered in the PALFA Survey. The Astrophysical Journal, Volume 834, Issue 1, article id. 72, 9 pp. (2017).

http://adsabs.harvard.edu/abs/2017ApJ...834...72L

<< A new discovery has upended the widely held view that all pulsars are orderly ticking clocks of the universe. A survey done at the Arecibo Observatory in Puerto Rico has fortuitously discovered two extremely strange pulsars that undergo a "cosmic vanishing act." Sometimes they are there, and then for very long periods of time, they are not. >>

The Mystery of Part Time Pulsars. Arecibo Observatory. Jul 18, 2017.

https://www.naic.edu/ao/blog/mystery-part-time-pulsars