Forum der Vereinigung der Sternfreunde

Hallo,

und wieder einmal möchte ich Euch auf ein Galaxienspektrum aufmerksam machen, das ich am 21.12.2021 habe aufnehmen können.

Das Zielobjekt war NGC 1275 - die Riesengalaxie im Perseushaufen, die auch als Radioquelle Perseus-A bekannt ist.

Hier der Link zum Blog-Beitrag ... https://www.astro-images.de/die-radioga ... ka-ngc1275.

Schöne Grüsse,
Michael

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http://www.astro-images.de
14"-Hypergraph, Spektrographen: Dados & LISA

Hallo Michael,

Few days ago I saw your excellent job about NGC 1275 and chose this galaxy as a test to
find the observational limit of the spectroscopic equipment of Santa Maria de Montmagastrell observatory, that is a SC16 + NOU_T echelle + ASI2600MM camera.

Yesterday night, with a normal, - not more excellent -, seeing level, I took 10 integrations of 1800 seconds to NGC 1275, 5 hours in total. The signal has been weak but sufficient to show the main bands with light pollution ones that I have tried to leave in this last graphic. Could you apply your reduction numbers in it, please? I would really appreciate it.

You can see the H alpha has a little Pleione effect,is it useful for calculating a possible rotation speed? I have left here for you, - and for all -, the NGC1275 files *.*fits, https://drive.google.com/file/d/12UkXj9 ... sp=sharing

You can see some png above all of that and I wrote in them "theoretical resolution" because it is possible the good signal is mixed with the noise.

BTW, it is possible here, https://www.astro-images.de/die-radioga ... ka-ngc1275. it has jumped one number in the fourth picture in the third row, is it 658.4nm or 654.8nm?

Thank you for everything, Joan.

Hello Joan,

thanks for your nice comment.

I have downloaded the FITS and I will review them in the next days - and will then provide feedback.

A first remark - be carefiul with the assumption of a rotating disk in the centre on NGC 1275. Most likely the regime we are investigating is dominated by in/outflow of matter.
Please see me latest post on the details of the Ha-line.

Nevertheless, I am curious what's in you data

Best wishes,
Michael

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http://www.astro-images.de
14"-Hypergraph, Spektrographen: Dados & LISA

Hallo Michael,

I don't know anything about analysis and theoretical galaxies evolution, that is the reason I would greatly appreciate your opinion about this observation, of course also I would be very glad that it could be useful for you.

If you need some observation of other NGC ones, tell me, but NGC1275 is my equipment border.

I'm looking forward to your explanations.

Cheers, Joan.

Hello Joan,

I have a quick glimpse yesterday evening - and I saw the FITS files, which you have produced.

With a fantastic solution - Great!

But what I haven't found - maybe due less time - is the raw spectrum. As you have seen in my posts, whenever I look for gas movement, or rotating disks, I use a raw spectrum produced with my slit spectrograph.

With the slit that lies "over" the galaxy core, I also create spectra nearby the core - and I get profiles by shifting the active binning zones.

So, looking at you spectra, I am not sure - am I right that you used a fibre and therefor a spot on the core?

Is this case, you only measure the core.

Or have you used a slit spectrograph?

Best wishes,
Michael

_________________
___________________________________________
http://www.astro-images.de
14"-Hypergraph, Spektrographen: Dados & LISA

Hallo Michael,

I made this observation with a NOU_T echelle, you can find some information about it  here in this Forum on, viewtopic.php?f=2&t=6334, and in Aras Forum on, http://www.spectro-aras.com/forum/viewt ... &t=1767and a bit more here, http://www.spectro-aras.com/forum/viewt ... f=6&t=2367.

As you say, I observed only the core of this galaxy.

This echelle uses a pinhole,  not an optical fiber.  I know that it isn't the best tool for the class of observations about the NGC galaxies that you need. I've observed the NGC1275 to know the detectivity border of my equipment, but would be delighted if it can be useful for you.

But if you believe sometimes that  I could make any observation, don't hesitate to tell me.

On the other hand, I'm building a new spectrograph with R around 1500 / 2000, - with a slit -,  that I hope I'll have finished this summer, but that is another issue..

Cheers, Joan.

Hello Joan,

I measured the redshift in your NGC 1275 spectrum - with 5223 km/s (filename ... _774_full.fits).
The deviation of the value to the NASA NED value is about 40 km/s, so its < 1%.

I am not familiar with echelle spectra, and what I would derive from your FITS file is a very good resolution, 10-times better than mine, a similiar SNR, and, noisier emission line slops - which makes the Gauss fit more difficult.

Nevertheless - you setup shows that "going to low magnitudes" is possible for echelle spektrograph.

Best wishes,
Michael

_________________
___________________________________________
http://www.astro-images.de
14"-Hypergraph, Spektrographen: Dados & LISA

Hallo Michel,

Many thanks for your study, job and appreciation, so if sometimes you need any observation that could be complemented by yours, don't hesitate to let me know.

Best regards, Joan.

Hello Joan,

thanks für this kind offer - I had the same thought

I will drop you my email, so we can stay in conact easily.

Best wishes,
Michael

_________________
___________________________________________
http://www.astro-images.de
14"-Hypergraph, Spektrographen: Dados & LISA