OJ287 - A Blazar

[Bill S]

Hello

The BAA has highlighted OJ287 as an object to have a look for and they are hoping variable star observers will send in some magnitude measurements.

I decided to see if I could see it with my setup (see below). It's the most distant object I've looked at - 3.5 billion light years.

Blazars are not fully understood but OJ287 is generally accepted to consist of binary supermassive black holes. The larger one is 18 billion solar masses and the 'small' one is 150 million.

More information here:

https://en.wikipedia.org/wiki/OJ_287

and

https://en.wikipedia.org/wiki/BL_Lacertae_object

(Blazar is a combination of BL Lac and Quasar.)

I convinced myself that I could see the actual object by checking against a finder chart:

https://www.lsw.uni-heidelberg.de/users/jheidt/spm/target/oj287/oj287.html

I also used All Sky Plate Solver to scan over the field and check the coordinates of the object.

The Moon was quite bright so I was glad I managed to catch this. (Mag 15.4)

Bill

 

 

[RobertI]

Interesting object, some useful background info, good catch. You also did well to track it for 30 minutes, your PA must have been pretty decent!

[Bill S]

Yes, Robert. The long stack reflects wandering back into the house and certainly pleased things kept stacking. OJ287 didn't really need this long. Once it's clear which 'star' it is then a handful of subs was enough to see it. Certainly 10 was enough.

Cheers

 

[coatesg]

Nice observation (And yes - this is an object with requested observations as it goes towards a predicted increase in brightness when the smaller black hole passes through the theorized accretion disc of the second - I had a go at magnitude measurement a few weeks back but got clouded out...). 

On 24/04/2019 at 00:31, Bill S said:

(Blazar is a combination of BL Lac and Quasar.)

is correct for the naming source, but it was named as such because Blazars encompass both BL Lac objects and OVV (Optically Violent Variable) quasars as sub types. (The distinction being the BL Lacs are related to radio weak galaxies, whereas OVVs relate to radio loud galaxies).

In reality, Blazars are a sub-type of the larger quasar group ("Quasi-Stellar Object" - appears point like like a star, but the spectra/variability is non-stellar), where the relativistic emission jets of the feeding black hole point along the line of sight for blazars - BL Lac and Blazar are often used interchangeably, but that's not quite the whole story ?

 

[Martin Meredith]

Hi Bill

Very interesting write-up, thanks. I see you have an IC galaxy in there and a few other fainter galaxies.

I will try to measure this one next time I'm out (unfortunately not until 2nd week of May).

Martin