SN 2022hrs bright in NGC4647

Robin Leadbeater
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Re: SN 2022hrs bright in NGC4647

Post by Robin Leadbeater »

Benjamin Mauclaire wrote:Hello,

Bertrand tu sembles confondre décalage Doppler et vitesse d'expension, respectivement ici de 248 A (-11699 kms) et 0.5fwhm=~100 A (4830 kms)

Benji
Hi Benji,

No Etienne is correct. The absorption line shows velocity in our direction. There is a spread of velocities at different depths but the mean velocity is that which Etienne has calculated. This is different from emission lines, for example in type II supernovae, where the width of the line shows the velocity between the maximum in our direction and zero to the side (and if optically thin, the velocity away from us)

Cheers
Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Robin Leadbeater
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Joined: Mon Sep 26, 2011 4:41 pm
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Re: SN 2022hrs bright in NGC4647

Post by Robin Leadbeater »

Etienne has made an error in his calculation though I think (wrong sign of the galaxy redshift)

The calculation is

Si II rest = 6355A
Si II at galaxy redshift = 1.0047x 6355 = 6385
doppler shift = 6385-6107 = 278A
doppler velocity of ejecta = C*(278/6385) = 13060km/s

This is typical for a type Ia supernova at maximum. See here for example
http://www.spectro-aras.com/forum/viewt ... =40#p12716

Cheers
Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Robin Leadbeater
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Re: SN 2022hrs bright in NGC4647

Post by Robin Leadbeater »

Juan Jose Pueyo wrote:Supernovae within the reach of amateurs have magnitudes usually between +12 and +18.
I could get to about mag 15.5 with my standard ALPY 600 and a Celestron C11. To go fainter I modified my ALPY to reduce the resolution and increase sensitivity. (R~100 is good enough for supernova confirmation. It is the same resolution used by the Zwicky Transient facility for example) Here are the details of the modification. Shelyak might offer this as an option in the future.
http://www.threehillsobservatory.co.uk/ ... opy_20.htm

I have also used it to measure quasars to z=4.5 at mag ~19
https://britastro.org/observations/obse ... ebf4faaefe


Cheers
Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Jacques Michelet
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Re: SN 2022hrs bright in NGC4647

Post by Jacques Michelet »

Captured with an RC12-Uvex600-Atik460ex configuration, a somewhat noisy spectrum of the supernova. Recognising any line pattern is really challenging.

Jacques
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SN 2022hrs spectrum
SN 2022hrs spectrum
Robin Leadbeater
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Re: SN 2022hrs bright in NGC4647

Post by Robin Leadbeater »

Jacques Michelet wrote:Captured with an RC12-Uvex600-Atik460ex configuration, a somewhat noisy spectrum of the supernova. Recognising any line pattern is really challenging.

Jacques
Yes the lines are so doppler shifted and blended by broadening making identification of the lines difficult (classification is generally done by matching to spectra of known supernovae at the same age.) This paper by Fillipenko is a good starting point
https://ned.ipac.caltech.edu/level5/Mar ... rames.html
and specifically for type Ia this review paper
https://arxiv.org/abs/1402.6337

Cheers
Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Joan Guarro Flo
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Re: SN 2022hrs bright in NGC4647

Post by Joan Guarro Flo »

Hello at all,

Taking advantage of last night's good seeing, I attempted to observe SN2022hrs, it's a bit out of my instrumental possibilities, but also it is possible that it would be useful for you, so I left its fits and information files here.

https://drive.google.com/file/d/1pwPFcb ... sp=sharing

Cheers, Joan Guarro.
Attachments
_SN2022hrs_20220505 GRA.png
_SN2022hrs_20220505 GRA.png (30.91 KiB) Viewed 2718 times
Juan Jose Pueyo
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Re: SN 2022hrs bright in NGC4647

Post by Juan Jose Pueyo »

Hi Robin,
Thanks for the information on spectroscopy of dim objects. I will contact you by email about it.
Greetings
Juan José Pueyo
Juan José Pueyo
Azara Obs.
Azara (Huesca)
Juan Jose Pueyo
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Re: SN 2022hrs bright in NGC4647

Post by Juan Jose Pueyo »

215 / 5.000
Resultados de traducción
Hello Joan
Fantastic spectrum of SN2022hrs with your échelle NOU. I thought that at resolution 9000 it was not possible to obtain spectra of such faint objects. An exposure of 3.5 hours is perfectly acceptable.
Greetings
Juan José
Juan José Pueyo
Azara Obs.
Azara (Huesca)
Peter Velez
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Re: SN 2022hrs bright in NGC4647

Post by Peter Velez »

[quote="Robin Leadbeater"}

Hi Juan José,

To guide on faint targets I offset guide using another star in the field. (I use PHD2 for guiding but it should be possible to do this with other guider programs.)

First I take a deep image of the field from the guider camera (typically 20x20 sec, aligned and stacked) and measure the difference in pixels X and Y between the star I want to guide on and the target. I also note the X Y coordinates of the centre of the slit.

I then add the XY offset to this, place the guide star at this position and start guiding. I usually then take a long guider exposure, say 15 sec to check everything is ok before starting a long exposure on the spectrum camera (typically 1-2 hours in 600 or 1200 seconds exposures)

...

Cheers
Robin[/quote]

Slightly off-topic (apologies Francois!) - I've written some Python code that achieves something similar and have posted about that in the Python section Juan (and Robin) if you are interested as it may assist.

Pete
Robin Leadbeater
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Re: SN 2022hrs bright in NGC4647

Post by Robin Leadbeater »

Peter Velez wrote: I've written some Python code that achieves something similar and have posted about that in the Python section Juan (and Robin) if you are interested as it may assist.
Plate solving looks a good solution. With this it should be possible to put the target on the slit and guide on a field star without ever seeing the target in the guide camera. I think Christian must have done something similar (by eye) here
http://www.spectro-aras.com/forum/viewt ... =10#p15624

Cheers
Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
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