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SN 2020jfo in M61

PostPosted: Tue May 12, 2020 1:59 pm
by Pascal Le Du
Hello

J'ai observé dans la nuit du 11/05/2020 la supernova SN 2020jfo qui se trouve dans la galaxie M61.
L'objet est aisément repérable sur l'image de la caméra d'autoguidage. Il en a été autrement au niveau des acquisitions des spectres.
De brusques rafales de vent ont perturbé le guidage et j'ai dû invalider de nombreux spectres bruts.
Le spectre réduit, fortement bruité, est les résultat de 30 minutes de pose.
Toutefois, Gelato confirme à 100% une correspondance avec le spectre d'une supernova de type II.
Configuration : Newton 0.2m F/D 5, Alpy600 avec une fente de 23µm et CCD 414EX en binning 1x1

I observed on the night of 05/11/2020 the supernova SN 2020jfo which is in the galaxy M61.
The object is easily spotted on the image of the autoguiding camera. It was different in terms of spectral acquisitions.
Sudden gusts of wind disrupted the guidance and I had to invalidate many raw spectra.
The reduced spectrum shows a lot of noise. It is the result of 30 minutes of exposure.
However, Gelato 100% confirms a correspondence with the spectrum of a type II supernova.
Equipment: Newton 0.2m F/D 5, Alpy600 with 23μm slit, CCD ATIK414EX binning 1x1

Sn2020jfo_fenteExcentreeNote2WEB.jpg
SN 2020jfo
Sn2020jfo_fenteExcentreeNote2WEB.jpg (150.83 KiB) Viewed 1153 times

FenteSurCibleWEB.jpg
Fente sur cible
FenteSurCibleWEB.jpg (176.65 KiB) Viewed 1153 times

Sn2020jfoWEB.jpg
Spectre 1D SN 2020jfo
Sn2020jfoWEB.jpg (38.72 KiB) Viewed 1153 times

gelatoplotWEB.jpg
Gelato
gelatoplotWEB.jpg (38.38 KiB) Viewed 1153 times

Re: SN 2020jfo in M61

PostPosted: Wed May 13, 2020 12:46 pm
by Pascal Le Du
Bonjour

Nouvelle observation de la SN 2020jfo dans de bien meilleures conditions et avec le même matériel.
Cette fois ci, 5 poses de 20 minutes exploitées.

New observation of SN 2020jfo in much better conditions and with the same equipment.
This time, 5 exposures of 20 minutes exploited.
Sn2020jfoWEB.jpg
Spectre du 12/05/2020
Sn2020jfoWEB.jpg (39.28 KiB) Viewed 1108 times

Comaparaison_SN2020jfoWEB.jpg
Comparaison 11-12/05/2020
Comaparaison_SN2020jfoWEB.jpg (63.41 KiB) Viewed 1108 times

gelatoplot2WEB.jpg
Analyse Gelato
gelatoplot2WEB.jpg (60.75 KiB) Viewed 1108 times

Re: SN 2020jfo in M61

PostPosted: Wed May 13, 2020 10:11 pm
by Robin Leadbeater
Hi Pascal,

With the slit in that position you should be able to get a nice spectrum of the galaxy as well for free :-
Cheers
Robin

Re: SN 2020jfo in M61

PostPosted: Fri May 15, 2020 3:58 pm
by Pascal Le Du
Hello Robin

Yes, I was able to make spectrum on a part of the galaxy M61, in addition I have beautiful lines in emission in the red.
I was able to identify the lines of the doublet [NII], the Halpha line and a line [SII]. In the blue, I think I also have the Hbeta line.
I was thus able to determine the redshift observed by my spectrum: z=0.005221. It is close to what is in the literature (z=0.005224).
The observed leakage speed is therefore 1564.91 km/s or 1543.11 km/s if we remove the heliocentric radial speed of 12/05 (-21.8 km/s).
On the other hand, it is difficult to deduce something about the speed of ejection of this type II supernova because it is not easy to determine with precision the shift of the hydrogen lines on my spectrum.
Maybe you can say more, Robin?


Oui, j'ai pu faire le spectre sur une partie de la galaxie M61, en plus j'ai de belles raies en émission dans le rouge.
J'ai pu identifier les raies du doublet [NII], la raie Halpha et une raie [SII]. Dans le bleu, je pense avoir également la raie Hbeta.
J'ai pu ainsi déterminer le redshift observé par mon spectre : z=0.005221.
Il s'approche de ce qu'il y a dans la littérature z=0.005224.
La vitesse de fuite observée est donc de 1564.91 km/s soit 1543.11 km/s si on enlève la vitesse radiale héliocentrique du 12/05 (-21.8km/s).
Par contre, il est difficile d'en déduire quelque chose sur la vitesse d'éjecta de cette supernova de type II car il n'est pas aisé de déterminer avec précision le décalage des raies de recombinaison de l'hydrogène sur mon spectre.
Peut être que tu peux en dire plus Robin ?

Sp2DredM61NotesWEB.jpg
Spectre 2D M61
Sp2DredM61NotesWEB.jpg (109.31 KiB) Viewed 1011 times


SpM61WEB.jpg
Spectre 1D M61
SpM61WEB.jpg (39.52 KiB) Viewed 1011 times

Re: SN 2020jfo in M61

PostPosted: Fri May 15, 2020 11:54 pm
by Robin Leadbeater
Pascal Le Du wrote:Par contre, il est difficile d'en déduire quelque chose sur la vitesse d'éjecta de cette supernova de type II car il n'est pas aisé de déterminer avec précision le décalage des raies de recombinaison de l'hydrogène sur mon spectre.
Peut être que tu peux en dire plus Robin ?


Hi Pascal,

The Balmer lines are P Cyni profiles so the emission component is at the galaxy RV and the explosion velocity can be estimated from the absorption minimum.TNS has a nice plotting tool for this so you can measure from your spectrum that the velocity is ~10000km/s currently. (It depends on which element is measured because we see to different depths for different lines)

Cheers
Robin

SN2020jfo_le_Du.png
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Re: SN 2020jfo in M61

PostPosted: Sun May 17, 2020 11:49 am
by Pascal Le Du
Thank you Robin :)

Re: SN 2020jfo in M61

PostPosted: Mon May 18, 2020 12:23 pm
by Vincent Lecocq
hello,

my 2 cents !

vincent

Re: SN 2020jfo in M61

PostPosted: Thu May 21, 2020 4:19 pm
by Vincent Lecocq
hello,

evolution of this SN ?

vincent

Re: SN 2020jfo in M61

PostPosted: Thu May 21, 2020 10:09 pm
by Olivier GARDE
Some results with a LISA spectrograph

The Sn spectrum taken with a RC400 @ f/5.5
Image

And calculating the ejecta velocity with PCyg profils of Balmer lines.
Image

And to confirm that this Sn is in M61, the spectrum of M61
Image

with the calculation of the redshift of M61
Image

SIMBAD value is 0,00523

Re: SN 2020jfo in M61

PostPosted: Sat May 30, 2020 4:14 am
by Peter Velez
Here is my contribution on this SN from last night.

21 x 300s LISA images binned x2 with a 23 micron slit through a Planewave CDK12.5. Imaging camera is an Atik 460EX. Imaged remotely at the iTelescope Facility at Siding Springs Observatory near Coonabarabran, NSW Australia. Processed with Demetra.

The 23 micron slit means that I am undersampling. When I manage to learn how to set the correct parameters in SimSpec I can optimise the rig.

At this early stage I'm pleased with the result. There are a couple of spurious spikes though the emission at around 6600 is genuine. I'm keen to learn how to identify particular absorption features to determine the velocity of the ejecta from the spectrum. If anyone can point me towards a useful publication or site for this I'd be grateful.

Pete