28 October 2020 at 8:45 am #574775Daryl DobbsParticipant28 October 2020 at 12:28 pm #583304
Here it is on my patrol image from early evening on Oct 26. M31 novae are very frequent and discovering them is very competitive. This image also shows AT 2020vak much closer to the core.28 October 2020 at 5:41 pm #583306
Has 2020vak been positively identified as an M31 nova? I am not saying it isn’t but it wasn’t clear from the amateur spectrum posted on TNS
Robin28 October 2020 at 6:04 pm #583307
You’re right. I tend to be very lax and use the term nova for anything that varies in M31. Transient would be a much better term to use. That spectrum doesn’t look very nova like. It is very close to the core though so how do you stop the spectrum being polluted by the background?28 October 2020 at 6:42 pm #583309
These are some I have managed to tease out in the past (full scale in the attachment)28 October 2020 at 6:43 pm #583308
Yes this one is against a bright background. This can be subtracted out using regions above and below the target in the slit but it does depend on this being uniform (both in brightness and spectroscopically) so you have to watch for galactic features.
The last time I checked the ATels this group were suggesting the spectrum resembles that of an F star. This rather rang alarm bells with me though as that is that is what might be expected from the integrated light from the galaxy. I see now here though it has been classified as an Fe II nova. What brightness would you estimate? (Not that I am going to be observing any time soon from the forecast. As I am writing this the hailstones are hammering on the window)28 October 2020 at 7:21 pm #583310Paul LeylandParticipant
Just a reminder: M31N 2008-12a is due to go off any day now. This recurrent nova goes into outburst at roughly 11-monthly intervals and reaches mag 18 or so at maximum. It is visible for only a few days each time and nightly monitoring of the field is recommended.
https://arxiv.org/pdf/1607.08082.pdf contains a finder chart and magnitudes in a number of photometric bands for a number of comparisons.28 October 2020 at 9:01 pm #583311
It is difficult to get a reliable magnitude but 2020 vak was around 16.6 (unfiltered vs Gaia DR2 G) on my image of Oct 26.8.28 October 2020 at 9:10 pm #583312
This is in one of my lesser patrolled fields around M31 (my field 15). I try to get a deep image of the core of M31 every available night but I’ll keep an eye on this field too. Nothing there at the moment.31 October 2020 at 10:27 am #583325
- You must be logged in to reply to this topic.