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Re: potentially bright supernova in NGC4636

PostPosted: Thu Jan 30, 2020 1:48 am
by James Foster
Here's the latest low-resolution spectra of Sn 2020ue, taken on 28Jan2020 (in NGC 4636):
Image
Balmer lines may form soon.......

James

Re: potentially bright supernova in NGC4636

PostPosted: Thu Jan 30, 2020 6:13 pm
by Robin Leadbeater
James Foster wrote:Balmer lines may form soon.......


? Type I spectra including type Ia supernovae spectra are characterised by their lack of Hydrogen
Here is a simple guide to supernova spectral classification
https://astrobites.org/2016/12/02/class ... upernovae/

Note your annotations are still incorrect see my previous post
viewtopic.php?f=38&t=2457&start=10#p13710

Cheers
Robin

Re: potentially bright supernova in NGC4636

PostPosted: Sat Feb 01, 2020 1:32 am
by James Foster
Most recent spectra:
Image
RE:"Note the lines marked as forbidden lines [OII] are the Telluric molecular bands O2 6869 and H2O 7186 eg..."

I'm aware of this but unable to edit the labels in Plotspectra, so I'll just omit them.....Hg is definitely a strong telluric in my
light polluted skies......Isis gets rid of most but not all!

Btw thanks for the SN guide......I was probably thinking of a certain class of Novae.....Here is a comparison of 22Jan20 vs 31Jan2020 spectra:
Image
What's great about supernovae is how quickly the spectra changes in a very short time!

James

Re: potentially bright supernova in NGC4636

PostPosted: Sat Feb 01, 2020 2:22 am
by Robin Leadbeater
Hi James,

The weather has been terrible here so I have not had the chance to take another spectrum but it looks like we are just past maximum now. SNID shows your spectrum from 28th gives an excellent match to typical Ia at maximum eg

_sn2020ue1x1_20200128_546_jamesrfoster2_snidflux.png
_sn2020ue1x1_20200128_546_jamesrfoster2_snidflux.png (38.81 KiB) Viewed 2553 times


Cheers
Robin

Re: potentially bright supernova in NGC4636

PostPosted: Thu Feb 06, 2020 10:26 pm
by James Foster
Here is my latest (06Feb20) spectrum of Sn 2020ue in NGC 4636:
Image
I made a small animation of the spectra from 22Jan20-06Feb20:
Image
The IR seems to be increasing so I'll shoot with the LISA before the moon spoils
this area by next week.

James

Re: potentially bright supernova in NGC4636

PostPosted: Sat Feb 08, 2020 1:36 am
by James Foster
Here is my LISA IR spectrum of SN 2020ue (2 hours of exposing at 2x2 bin with LISA in IR mode):
Image

Here is a stitched visual(06Feb2020) and IR(07Feb2020) spectra:
Image
Still very little activity in the IR, but those bumps btw 7605/8300A and 8500/9000A are bigger than the last IR
spectrum taken 1 week ago, emerging warm dust?

James

Re: potentially bright supernova in NGC4636

PostPosted: Sun Feb 09, 2020 1:05 am
by Robin Leadbeater
Hi James

The dip at ~7600 (with the telluric band in the middle) is likely O I and the dip at ~8300 is likely Ca II (both in absorption)

If you want to try identifying the lines (not straightforward because of the blending of the broad lines and the large doppler shifts) the paper "optical_spectra_of_supernovae" by_Filippenko 1997, is a good guide, although perhaps getting a little old now. You can find it here

https://ned.ipac.caltech.edu/level5/Mar ... rames.html

fig 6 is particularly relevant here

1a_7days_past_max.png
1a_7days_past_max.png (45.52 KiB) Viewed 2436 times


Important ! dont forget to remove the galaxy redshift from the spectrum before trying to identify the lines and remember that absorption lines can be significantly blueshifted by the expansion velocity

Cheers
Robin

Re: potentially bright supernova in NGC4636

PostPosted: Sun Feb 23, 2020 4:13 pm
by James Foster
RE: "The dip at ~7600 (with the telluric band in the middle) is likely O I and the dip at ~8300 is likely Ca II (both in absorption)"
Good information Robin! Here is the latest spectra of SN 2020ue, taken before my local weather got bad:
Image

Just to let you know I didn't forget, here is my non-transformed BVRI magnitude curves for the SN taken with my C-11 at F/6.3 with Astrodon BVRI photometric filters:
Image
Peak B magnitude looks like it was on 25 Jan 2020, while the VR mag peak was around 26.5 Jan 2020. the Ic peak magnitude seems to precede these dates; 21 Jan 2020 for Ic peak?
The transformed BVRI magnitudes were uploaded to the AASVO last week; see:

https://www.aavso.org/apps/webobs/results/?star=SN%202020UE&num_results=200

James

Re: potentially bright supernova in NGC4636

PostPosted: Sun Feb 23, 2020 11:32 pm
by etienne bertrand
Bravo pour les spectres !

Re: potentially bright supernova in NGC4636

PostPosted: Wed Mar 04, 2020 2:17 am
by James Foster
This is probably the last spectra of SN 2020ue I'll take since its dropping below 15th magnitude and the figure isn't changing much; and the Hg lines are stronger relative
to the weak SN signal. I overlayed my last spectra I did 16Feb20 with this 03Mar20:
Image
I'll supply photometric data up to next week when I finish my magnitude run with the C-11 with Astrodon photometric filters.

James