SN 2022pgf in NGC 5894 and SN 2022prr in NGC 6745

[Bill S]

One from a few days ago 29 September. The host galaxy is NGC 5894, an edge on spiral galaxy about 130 million light years away. The galaxy is listed as SBm. The supernova was discovered on 22 July this year and is a Type II i.e. a core-collapse. I was pleased to see it is was still clearly visible.

 

 

The same night I also looked at NGC 6745 to see if I could see SN 2022prr. This was discovered on 27 July. With a bit of wishful thinking I believe I can see it. The galaxy is an irregular galaxy about 206 million light years away. The supernova has been classified as a Type IIn. The n refers to particularly narrow spectral lines possibly linked to interaction of the ejected material with gas around the star.

 

Bill

[Mike JW]

Well done Bill, no clear spells for me to observe and of course the moon is getting in the way (and the wind).

Mike

[Xio1996]

Hi Bill,

That is amazing. Where do you get information on the latest supernova events? 

Many thanks

Pete

[Mike JW]

Hi Pete,

Here is one source: 

Latest Supernovae (rochesterastronomy.org)

Mike

[Bill S]

Hello Pete

Yes, indeed. The Rochester one is where I normally look.

Cheers

Bill

 

 

[Bill S]

Incidentally I still find it amazing that I could see the NGC 5894 and its supernova so easily. I posted an 8 minute snapshot to show things clearly but things were perfectly obvious in a 15 second sub.

[Xio1996]

Thanks Mike and Bill for the link. The website was very interesting.

I use a software tool called AstroPlanner to create my observation lists and record my observations. What I didn't realise is that it supports the import of supernova information from the very site you kindly told me about.  Bill, you have definitely inspired me to try a view a supernova on the next clear night.

I did have one question. The supernova data from Rochester gives the RA and Dec and then gives an 'Offset' field such as 6.9W 40.3N or 0.0 or even 0.0W 0.0N.  I wondered what the offset referred to? Is the offset applied to the RA/Dec fields to give the true RA/Dec of the object? That confuses me as surely you would just give the RA/Dec of the supernova. 

Many thanks for the great images, help and inspiration.

Pete

 

[Mike JW]

Hi Pete,

Offset figures - no idea what they mean.

Mike

[Martin Meredith]

I see mentioned on the URL Mike provided that people are sometimes asked to provide an offset from the nearest star to help with identification. Maybe that is it?

Martin

[Mike JW]

I wasn't intending to take a look at NGC 5894 and its SN but having finished fine tuning the guide rate on my Dob I pointed the scope to it, despite the blazing moon.

As with Bill, the SN was easily visible in just one sub and as the stack developed, I was delighted to get a hint of structure at the southern end.

Thanks Bill for the heads up for this SN.

Mike

[Bill S]

Re. The offset figures.

Martin Meredith's suggestion that the offset refers to a nearby bright star is reasonable because, as he says, the front page of the Rochester supernovae website talks about that.

There is another possibility. Some details of supernovae refer to an offset from the centre of the host galaxy. For example

The ASAS-SN Bright Supernova Catalog – IV. 2017 ...   '...we report these coordinates in Table 1. The offsets between the SNe and the centers of their host galaxies are also reported in the Table...'

https://arxiv.org/pdf/1811.08904.pdf

In this paper the offsets are in arcseconds.

It's of interest what the offset refers to but not of importance for using the website so far as I can see.

Thank you for your interest and comments. Happy supernova spotting!

Regards

Bill

[Martin Meredith]

I must say, Bill's suggestion of the meaning of offset makes a lot more sense to me. The bright star may be ambiguous, whereas the galactic centre is not. Perhaps the size of the offsets will indicate which of the two possibilities is most likely...

[robin_astro]

The coordinates given are for the supernova. The offset given is from the "centre" of the galaxy, the coordinates given in the catalogue for the galaxy eg for SN 2022pgf in NGC5894 as in SIMBAD

https://simbad.cds.unistra.fr/simbad/sim-basic?Ident=NGC+5894

to the supernova coordinates in TNS

https://www.wis-tns.org/object/2022pgf

ie  from 15 11 40.9482635976 +59 48 32.047254360

to 15:11:41.900 +59:49:12.29

Cheers

Robin

Edited October 8, 2022 by robin_astro
clarification

[Bill S]

Thank you for sorting that out for us, Robin.