Nova in Cassiopea (nova Cas 2020)

Alerts and Monitoring of Novae

Nova in Cassiopea (nova Cas 2020)

Postby Francois Teyssier » Thu Jul 30, 2020 10:09 am

A faint nova was discovered in Cassiopeia

Discovery: 2020 Jul 27.930 UT on images obtained with an F=135mm f/2.0 telephoto lens as part of the NMW survey (Sokolovsky et al. 2014, ASPC, 490, 395),
http://www.astronomerstelegram.org/?read=13903

AD: 00 11 42.97
DE: +66 11 19.0

Classified as a nova on spectra taken with SAI 2.5m telescope on July 29.025 UT

http://www.astronomerstelegram.org/?read=13905

The object is rather faint (V mag ~13-14)

Spectra are welcome for the database
Send spectra to francoismathieu.teyssier@bbox.fr
and a copy to arasdatabase@gmail.com
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Re: Nova in Cassiopea (nova Cas 2020)

Postby Robin Leadbeater » Thu Jul 30, 2020 11:42 am

Francois,

Before I consider sending further spectra to ARAS can you please clarify the terms for the use of spectra submitted to ARAS ?

The conditions state

Use of these data in research publications is encouraged subject to the following conditions:
* The observers concerned should be contacted to confirm the particular acquisition and data reduction procedures used.
* Observers contributing should be aknowledged
* Observers contributing a significant amount of data or whose data are pivotal to the findings of the paper should be included as co-authors.
*ARAS group should be aknowledege with a reference to the database
Please contact François Teyssier
francoismathieu.teyssier [at] bbox.fr
before submitting the publication



Were you contacted by the authors of this paper ?
viewtopic.php?f=33&t=2588

It specifically includes several of my spectra but I was not contacted or invited to be a co-author. (My e mail address is in the header of all my spectra)

fig 2 which was used to determine the temperature and spectral characteristics at maximum.
fig 6 which was used to identify the separate components in the the emission shell.
fig 5 where the H alpha FWZI plot depends entirely on measurements from spectra of observers who sent data to ARAS

I have tried to contact the first author but have not had a reply.

Thanks
Robin
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Re: Nova in Cassiopea (nova Cas 2020)

Postby David Boyd » Thu Jul 30, 2020 1:27 pm

Robin,

I have found spectra I submitted to the ARAS database included or referred to in papers in the past but I cannot recall ever having been contacted by the authors directly. However I have been acknowledged either by name or collectively as part of the ARAS team in the paper and I consider that an acceptable situation. When I submit a spectrum to the ARAS database, I consider I am putting it in the public domain and I am pleased if I subsequently find that it has been considered sufficiently useful to contribute to a publication in which I receive an acknowledgement. However the use of spectra from the database without acknowledgement I would consider a breech of protocol.

David
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Re: Nova in Cassiopea (nova Cas 2020)

Postby Benjamin Mauclaire » Thu Jul 30, 2020 3:10 pm

Hi,

@Robin:
Unfortunatly the terms for the use of spectra submitted to ARAS like the terms for Bess [1] are simply advising (in both verb used is "should") aknowledgement etc.
Therefore you can't hope any systematic aknowledgement or co-author invitation.
This situation is a rather sad because this encourarge professionnal considering amateurs as "monkey pushing button" rather than sharing knowledge and developping more full pro-am collaborations.
Anyway with the coming professionnal large automated surveys included in spectroscopy, amateurs contributions will become probably less and less usefull.

@David:
You may have in mind that not all observers have not the same feeling as you about how dataset can be used in papers. Amateurs have many flavours about that.
As the terms for the use of spectra submitted to ARAS specify to contact Francois, I don't understand why you answered to Robin's question which deals with this sibject.

[1]: http://basebe.obspm.fr/basebe/MenuThank.php

Benji
Spcaudace spectroscopy software: saving you hundred hours of frustration.
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Re: Nova in Cassiopea (nova Cas 2020)

Postby Robin Leadbeater » Thu Jul 30, 2020 8:17 pm

David Boyd wrote:I have found spectra I submitted to the ARAS database included or referred to in papers in the past but I cannot recall ever having been contacted by the authors directly.


Exactly and that is a problem which we still face despite this coming up in the past. The contributor of the data should at least be contacted, not only as a matter of courtesy but to check the validity of the data. (publishing a paper using data from an unverified source is not good practise.)
In the past I have been accused of not including amateurs who submitted spectra on a particular object as co-authors even when their spectra were not even used in the paper !

The conditions clearly state that Francois should be contacted before publication in which case I would hope that he would then let the contributors know

There is perhaps a different attitude to spectra in "amateur" and professional databases. I have been contacted several times concerning supernova spectra in TNS for example. In this particular paper there appears to be more data from amateurs than professionals. It would be interesting to know what contribution the other co-authors made.

Robin

Cheers
Robin
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http://www.threehillsobservatory.co.uk
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Re: Nova in Cassiopea (nova Cas 2020)

Postby Christian Buil » Fri Jul 31, 2020 2:24 am

(updated with 7x1200 s, but presence of cloud...)

A spectrum of V=13.5 nova Cas 2020, Newton 250 mm f/4.5 + eShel spectrograph at R=12000 + ASI6200MM camera. The object is faint and the spectrum is dominated by the Cote d'Azur sky pollution (well visible, related to high detectivity of the setup) :

Image

Detail of the Halpha line :

Image

The measured FWHM for Halpha is 470 km/s.

Christian Buil

Note : principal sky pollution lines : Na at 5683-5688, Na et 6154-6161, Na at 4978-4983, Na at 5149-5153 + thin Hg lines at 4358, 5461, 5770, 5971.
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Re: Nova in Cassiopea (nova Cas 2020)

Postby Francois Teyssier » Fri Jul 31, 2020 10:08 am

Impressionnant Christian!
Tout ça avec un 250 mm.


Amicalement,
François
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Re: Nova in Cassiopea (nova Cas 2020)

Postby etienne bertrand » Fri Jul 31, 2020 10:27 am

C'est quand même problématique d'avoir la pollution lumineuse sur le spectre eshel. C'est pas possible de l'enlever ? Au niveau science comment ça se passe si des pros veulent utiliser le spectre ?
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Re: Nova in Cassiopea (nova Cas 2020)

Postby David Boyd » Fri Jul 31, 2020 10:36 am

A spectrum of Nova Cas 2020 recorded with a LISA spectrograph on a C11 SCT and calibrated in absolute flux using a concurrently measured magnitude of V = 13.395. Using PlotSpectra, the integrated absolute flux of the H-alpha and H-beta lines are 3.53E-12 and 2.52E-13 erg/cm2/sec respectively. These results are consistent with the values 3.54E-12 and 2.54E-13 reported in ATel 13905. The apparent FWHM of the H-alpha line is 508 km/s and there is evidence of weak P Cyg absorption on the blue side of H-alpha extending to -800 km/s relative to the peak of emission. There are also emission lines of Fe II 5018, Fe II 5169, [O I] 5577 and an unidentified emission line at ~6160 A.

novacas2020_20200730_905_D_Boyd.png
novacas2020_20200730_905_D_Boyd.png (25.24 KiB) Viewed 1647 times


novacas2020_20200730_905_D_Boyd_2.png
novacas2020_20200730_905_D_Boyd_2.png (55.59 KiB) Viewed 1647 times

David
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Re: Nova in Cassiopea (nova Cas 2020)

Postby Christian Buil » Fri Jul 31, 2020 12:25 pm

Hi David, excellent and fine lines identification.

I have updated my echelle spectal profil by adding more exposures (now 7x1200 s + some cloud - see my first message). The "P-Cyg" is well visible (but clearly blue shifted).

Also the, 5577A line is intense (more in my high resolution spectrum because the very small Equivalent Width of the line and the convolution effect of low resolution). I detect (faintly) also Fe II lines at 5018 and 5169 :

Image

Etienne, oui c'est problématique. En fait oui et non. Soit je me dis que je ne peux pas observer car j'ai un ciel pollué et une fibre, soit j'observe car je sais que localement j'aurais de la bonne information (le profil Halpha par exemple) et ce avec une résolution peu commune (détails dans la raies). Le choix est vite fait !

Il faut voir qu'en haute résolution, le qualité du fond est moins critique (dans une certaine mesure). C''est pour cela qu'il est plus facile de faire de la haute résolution. que de la basse résolution spectrale ... toujours !!!

Sinon, il faut (1) que tu me trouve un observatoire moins pollué (mais la Cote d'Azur à ces charmes aussi, attention !), (2) que l'on fabrique une bonnette à double fibre dont l'une prend le ciel (peut-être un jour), (3) que je fasse une seconde pose de 2 heures à coté, mais là le jour venait, et je n'ai pas envie de passer du temps à cela vu ce que j'ai dit sur l'exploitation astrophysique des spectres haute-résolution (on pourrait aussi dire que c'est problématique de ne pas travailler en haute résolution, car on mesure mal une raie comme [OI] car trop fine pour un Alpy ou un LISA - en fait rien n''est simple).

Christian B
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