spectro-aras.com

Not easy at low resolution.

From echelle spectrum (R = 9000) acquired last night.

"5309"

The shape is similar to Balmer, He I, single ionized lines, notably Fe II (broad component from the ejecta and narrow line from the symbiotic nebula)
Thus it is very probably a single ionized line (Fe II, Si II)
Fe II 5316.23 is an excellent candidate.
"5677"

We observe only the broad component, thus formed in the ejecta only.
I think it is NII 5676 ("allowed") BTW, [NII] has increased (*according to the continuum*)
and [OIII] 5007, 4959 are growing
In eshel spectra, we note the first traces of [Fe VII] and [Ar III] - only narrow component, formed in the symbiotic nebula.
Waiting for higher ionized species ...! in the next weeks.

Bonjour à tous

Malgré une météo brumeuse, (seuls Antares et Del Sco étaient visibles dans le secteur !) spectres Nova avec G1200 dans l'UV.
Pas mal de bruit compte tenue des conditions météo

Apparition de nouvelles raies Fer ??
résolution > 2100
A refaire dans de meilleures conditions


Pierre

My latest contribution - taken on 20 August 2021 with the UVEX 600 lines/mm grating. Based on the UV.

Some lines identified. For some reason the Fe II lines are blue shifted - is this to be expected or is my calibration to blame?

Pete

Hello Peter

Good job whith UVEX

for calibration what is your process ?
where did you find the lines identifications ?

to be continued

Pierre

Pierre,

I am using the ArNe Alpy calibration unit. Up in the UV it can be challenging so if I get stuck I can also use the Balmer lines of a reference star to set the polynomial. Its more involved but works as a back up.

I find it easiest to first process the spectrum with Demetra. This gives me a quick look to assess my data. I then reprocess in ISIS using the master dark, offset and flat frames produced in Demetra. I also find it easier to use Demetra to produce the instrument response for the reference star and apply that in ISIS too.

To start identifying lines, I have a very basic python script that relies on the Specutils module to produce a list of wavelengths with absorption and emission lines. I assembled this from a number of sample scripts available online - I’m a lawyer by training not a programmer! It’s not perfect but is a good place to start. I then look to match this list to a lines list suitable for the target and mark them with Plot Spectra. I then cross check them against other spectra if any are available. For example, David Boyd posted a very clear annotated spectrum last week for RS Oph.

For me the biggest challenge is understanding which identifications are correct and which are spurious. Francois T’s seminar on novae earlier this year has been very helpful. He also has some great resources on his website.

Lastly, I rely on corrections from others on this forum when I have gone off piste. Happily everyone is quite polite when that happens.

Pete

Nice one peter!

further growth perhaps of the OIII line at 5006 emerging?

Hi Friends,

Good job whith UVEX
for calibration what is your process ?

The subject of this topic is the nova outburst of RS OPh in 2021, its photometric and spectroscopic development, the underlying physics ...

For technical discussions, please use the dedicated forum (including for instance a link to the post in the current forum.

Thanks in advance,
François (as Admin)

where did you find the lines identifications ?

This question is in the context of this topic. More very soon!

Attempt of lines identification on echelle spectra secured respectively by Joan Guarro and François Teyssier.
For He II 4686, [Fe VII] the following monitoring will allow to remove the doubt.
At date, we are almost sure of [Ar III]
Of course, any question or critism will be very welcome.

I will provide a link to the csv file

Near UV
The identification proposed by Peter looks pretty good. More tomorrow.
I appreciate the guideline: only obvious lines at low resolution are identified.

@ Hamish: yes, Peter's spectrum show clearly the growth of [OIII] 5007 on the blue part of HeI/FeII 5016/5018 blend

All the best for this very good monitoring.

François

What causes the shape of the HeI 6678 line with apparently absobtion in the middle of the broad emission hump?

Wonderful echelle spectra by the way, congratulations on the technical achievement!

Last night was first decent clear sky since my last posting. Using Lhires III with 35um slit and 2400l/mm grating I captured five 300 second subs through C9.25 sct.
Alun