Thread by @CosmicRami

And while we're on the topic of #Pulsars, an exciting thing happened in the last few days ... the relatively nearby #VelaPulsar happened to glitch again!

Vela is known to glitch every 2.5-3 years, so let's dig in with a short thread on why this is exciting.

📸 Chandra Obs.

First of all, here's the @astronomerstel notification: astronomerstelegram.org/?read=14806

But I heard about it through Pro-Am radio astronomer (and friend!) @hawk_RAO who picked it up early!

https://twitter.com/hawk_RAO/status/1418528390659727362

Steve runs the Hawkesbury Radio Observatory just near Sydney.

Steve (@Hawk_RAO) is no stranger to using his home radio observatory set up of Yagis to detect pulsars and has previously detected a Vela pulsar glitch in the past!

Have a listen to this excellent conversation with Steve on the @Astrophiz podcast: spaceaustralia.com/opinions/astro…

But let's first talk about the Vela pulsar.

The Vela pulsar was born in a huge supernova explosion that occurred about 12,000 years ago in the constellation Vela.

The remnant expanding cloud from this huge detonation can still be seen today.

📸 R. Gendler/R. Colombari/DSS

The explosion produced a bright pulsar, that is observed in radio, optical, x-rays and gamma rays.

This massive compact object, weighing in at about ~1.5 times the mass of our Sun, rotates on its axis about 11 times per second.

📸 NASA/CXC/PSU/G.Pavlov et al.

Want to hear what the Vela pulsar 'sounds' like? (along with a range of other pulsars that have been sonified?)

Well, @UoM_Pulsars has you covered on this page.

To me, Vela sounds like a fast Diesel engine or standing under the blades of a helicopter!

astrosurf.com/luxorion/audio…

The Vela Pulsar is also another astronomical object that has a historical connection with the city of Sydney when researchers from @Sydney_Uni reported the association between pulsar and the supernova remnant.

Read the paper from 1968! nature.com/articles/22034…

So what is a 'glitch' when it comes to pulsars, and why is this important?

Pulsars are like *incredibly* accurate clocks, and they pulse (tick) with periodic regularity that can be measured down to many, many decimal places.

This allows scientists to run timing experiments.

Precision timing experiments in fact!

The regularity of these ticks allows astrophysicists to do a lot of fun things. Esp. given pulsars are such high mass compact objects, spinning very fast, sometimes have companions, etc.

IT IS FUN SCIENCE MY FRIENDS.

Through a number of mechanisms (like the emission of EM energy through the pulses themselves, the pulsar wind nebula, etc.) we have also measured *EXTREMELY ACCURATELY* that pulsars spin periods slow down.

It's tiny, but it is measurable.

📸 Kramer, Lyne & Smith

And by knowing the spin down rate to a high degree of accuracy, we can then start to model what the future spin rate of each pulsar will be, so we have a 'prediction' to test scenarios against. There are loads of applications for all the fun science to be had!

But every now and then, some pulsars decide to do something a little weird. Instead of continuing on their expected spin down period, they _glitch_ and jolt back up to a higher spin rate.

For the most time, this eventually recovers back.

📸 C. van Eysden (2011)/Astrobites

The jury is still sorta out as to what exactly can cause glitches, but for the most part, folks think that it has to do with the internal structure of pulsars.

The matter on the inside of these objects is *extreme*, crushed under immense gravity/pressure.

📸 Harvard CfA

And for this reason, glitches on pulsars are excellent probes as to what could be happening when matter is crushed into such extreme conditions - they give us a laboratory to test models and theories against, as we would never be able to recreate these conditions here.

You can check out the catalogue of Pulsar glitches on this site here, which also have lots of links to the reference papers and analysis of each glitch: jb.man.ac.uk/pulsar/glitche…

Some pulsars appear to have a periodic glitch (e.g. Vela roughly glitches every 2.5 - 3 years), and others might be more longer term.

Using the UTMOST instrument, Australian researchers detected a glitch in PSR J0908-4913 after 30 years!

spaceaustralia.com/feature/pulsar…

So glitches in pulsars are important for lots of astrophysics, and better understanding of how matter behaves.

In 2016, scientists at the @UTAS_ observed the Vela Pulsar glitching 'live' for the first time! Very cool!

Read this paper: nature.com/articles/s4158…

Maybe The Matrix films had it right after all, the glitch in the system means something inherently changed with the pulsar.

Guess we’ll have to wait for around the start of 2024 to see if Vela glitches again!

Also - shout out to amateur radio astro folks with this stuff! 👏🏼

And apologies* friends, that thread went a little bit longer than expected!

With all the doom and gloom around these days, I hope you found it interesting!

Pulsars are the best, and science rocks - esp. with so many Aussie local story tie ins.

(* sooo very not sorry)