Supernova at mag 11.8 in NGC5297 (Update: False alarm, alas)

[michael.h.f.wilkinson]

Just spotted an alert here, that a bright SN labelled AT2023mlt has been spotted in NGC5297. Would love to have a chance to spot that, as the SN is well within reach of my C8, and I haven't bagged that galaxy yet (mag 11.7 according to Wikipedia). Has anybody else spotted this?

 

Update: as posted below, the observation turns out to be a false alarm.

 

[John]

I'd spotted the entry on the Rochester database but I have not had a chance to seek it out yet. The host galaxy is in the same part of the sky as M 51 so quite well placed. Forecast here is rather pessimistic for the coming days though 😒

If we get a clear spell then this should be within reach of my 100mm and above scopes. 

It would be good to see a reference image to get an idea where the SN lies relative to the host galaxy.

Thanks for the heads up on here 🙂

 

[michael.h.f.wilkinson]

11 minutes ago, John said:

I'd spotted the entry on the Rochester database but I have not had a chance to seek it out yet. The host galaxy is in the same part of the sky as M 51 so quite well placed. Forecast here is rather pessimistic for the coming days though 😒

If we get a clear spell then this should be within reach of my 100mm and above scopes. 

It would be good to see a reference image to get an idea where the SN lies relative to the host galaxy.

Thanks for the heads up on here 🙂

 

Forecast not good here either. I do hope to take my 8" scope for a spin next week, from a more southerly point on earth, with a better forecast. Fingers crossed it doesn't fade too fast

[michael.h.f.wilkinson]

I have just used the AAVSO Variable Star Plotter to create these maps, with and without DSS data:

There is this very bright star in the image close to the reported SN. This would suggest finding the SN should be easy

[Stu]

31 minutes ago, michael.h.f.wilkinson said:

I have just used the AAVSO Variable Star Plotter to create these maps, with and without DSS data:

There is this very bright star in the image close to the reported SN. This would suggest finding the SN should be easy

Thanks Michael. What’s the mag of that star, for reference/comparison?

[Malpi12]

19 minutes ago, Stu said:

Thanks Michael. What’s the mag of that star, for reference/comparison?

I'm not Michael but I am just setting up my Stellarium for this. it says m9.4 in my version, no moniker though, I'll look in CdC later for it

Edited July 11, 2023 by Malpi12

[Malpi12]

41 minutes ago, michael.h.f.wilkinson said:

AAVSO Variable Star Plotter       with DSS data:

Thanks for the alert @michael.h.f.wilkinson  -  and Ohh I didnt know DSS could be added, must have another look in the aavso destructions !. I always have trouble aligning aavso charts with stars in stellarium, this should make life a lot easier.

I shall have to go portable to catch this one as it is below my treeline all night from my home. 

[Malpi12]

 

eeek aavso is telling me AT2023mlt "Star AT2023mlt does not exist in VSX"  what am I doing wrong I wonder ?

[robin_astro]

it is a false alarm and does not exist

https://www.wis-tns.org/object/2023mlt

Robin

[robin_astro]

1 hour ago, Malpi12 said:

 

eeek aavso is telling me AT2023mlt "Star AT2023mlt does not exist in VSX"  what am I doing wrong I wonder ?

Even if it had been a transient (it is only a supernova once confirmed by spectroscopy, it would only exist in VSX after somemone added it.  TNS (Transient Name server) is the definitive place to look for possible and confirmed supernovae

 https://www.wis-tns.org/

 

Robin 

Edited July 11, 2023 by robin_astro
added link

[Malpi12]

10 minutes ago, robin_astro said:

it is a false alarm and does not exist

https://www.wis-tns.org/object/2023mlt

 

Thanks  @robin_astro,
I wondered if that might be the case ! as the "Type" on the Rochester page was "unconfirmed"
but the date was 6th, which was a long time to be still on the page with nothing in their updates page
  and tks for the def. link 
 

[robin_astro]

Even if it had existed it would have been too bright for any normal supernova at maximum at the distance of the suggested galaxy so would likely have been a transient object in our own galaxy (nova, dwarf nova, luminous blue variable etc etc) but since it does not exist that is hypothetical  The correct procedure for reporting transients is to make a follow up observation first and check for any other possible sources eg asteroids etc. Only then should a discovery claim be made either through TNS or via the IAU transient object page

http://www.cbat.eps.harvard.edu/unconf/tocp.html

 

[robin_astro]

It was withdrawn on TNS on Saturday within a few hours of its "discovery".   It is labelled as "unconfirmed" in David Bishop's "rochester" page meaning that someone has looked there and not found anything

[Malpi12]

10 minutes ago, robin_astro said:

Even if it had existed it would have been too bright for any normal supernova at maximum at the distance of the suggested galaxy so would likely have been a transient object in our own galaxy (nova, dwarf nova, luminous blue variable etc etc) but since it does not exist that is hypothetical  The correct procedure for reporting transients is to make a follow up observation first and check for any other possible sources eg asteroids etc. Only then should a discovery claim be made either through TNS or via the IAU transient object page

http://www.cbat.eps.harvard.edu/unconf/tocp.html

The other thing that had me puzzled is that if it had been mistaken ID with the nearby star the magnitude difference was so large how could it have been such a mistake ! So I eeeked !!
 

[michael.h.f.wilkinson]

22 minutes ago, robin_astro said:

It was withdrawn on TNS on Saturday within a few hours of its "discovery".   It is labelled as "unconfirmed" in David Bishop's "rochester" page meaning that someone has looked there and not found anything

Thanks for the information. Will have to wait for the next REAL bright one to pop up

[robin_astro]

It exists in the image posted with the discovery (see the fits file from TNS). I don't know why it was withdrawn but there are several possibilities eg not seen in a follow up image, identified as asteroid, hot pixel etc etc

[robin_astro]

Not long ago, a large professional team posted the discovery of a bright transient on TNS which when I checked matched the coordinates of Neptune 😉 

https://britastro.org/forums/topic/an-independent-discovery-of-neptune

Cheers

Robin

Edited July 11, 2023 by robin_astro
added link

[Malpi12]

Looking on the bright side - now that we have nothing to see the rain-gods will take time off and we will have an exceptional clear sky tonight
 

[John]

It is still going to be difficult to resist the temptation to have a look at NGC 5297 at the next decent opportunity "just in case" 😁

[michael.h.f.wilkinson]

5 minutes ago, John said:

It is still going to be difficult to resist the temptation to have a look at NGC 5297 at the next decent opportunity "just in case" 😁

I want to pick the galaxy up anyway

[Paul M]

Well that's a disappointment. I was, for a few minutes at least, looking forward at a bright new supernova to drag me out of  the summer doldrums!