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SN2020uxz in NGC 514

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#1 NJScope

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Posted 10 October 2020 - 10:59 AM

A bright new supernova (SN2020uxz) was discovered (K. Itagaki) when it was at Vmag 16.5 (Oct 05.575) in NGC 514.   Below is an image captured this morning (Oct 10.264) showing that it has brightened considerably.  Thus far data from the IAU Transient  Name Server suggests it is type SNe 1a.

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  • SN2020uxz_FOV_10Oct2020_v2.png

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#2 Rich (RLTYS)

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Posted 10 October 2020 - 03:10 PM

Will have to take a look at this new SN. Thanks for the info.waytogo.gif



#3 NJScope

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Posted 13 October 2020 - 12:35 PM

SN2020uxz is still brightening (V-mag ≈14.2) at 10:04:10 UTC this morning (Oct 13, 2020):

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  • SN2020uxz_90sec_Clear_FOV.jpg


#4 Rich (RLTYS)

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Posted 13 October 2020 - 03:01 PM

Using the Slooh T1hm scope I did my first observation of SN 2020uxz on the 13th. Estimated mag 14.110.

 

#TYPE=EXTENDED
#OBSCODE=TYS
#SOFTWARE=VPhot 4.0.7b
#DELIM=,
#DATE=JD
#OBSTYPE=CCD
#NAME,DATE,MAG,MERR,FILT,TRANS,MTYPE,CNAME,CMAG,KNAME,KMAG,AMASS,GROUP,CHART,NOTES
SN 2020uxz,2459135.60397,14.110,0.025,V,NO,STD,129,-7.267,124,-7.811,1.68,na,X25677CZC,na



#5 NJScope

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Posted 15 October 2020 - 12:12 PM

Nearly 10 days since discovery, SN2020uxz continues to brighten (Vmag~13.85 ±01) with clear filter:

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  • SN2020uxz_ClearFilter_FOV.jpg


#6 robin_astro

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Posted 16 October 2020 - 06:13 PM

A spectrum from last night (ALPY 600 8x10min ~12A resolution) overlaid on the best fit from SNID, the supernova identification program (red)

 

_sn2020uxz_20201015_892_leadbeater_SNID.png

 

 

Cheers

Robin 


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#7 mwr

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Posted 17 October 2020 - 04:10 AM

A spectrum from last night (ALPY 600 8x10min ~12A resolution) overlaid on the best fit from SNID, the supernova identification program (red)

 

attachicon.gif_sn2020uxz_20201015_892_leadbeater_SNID.png

 

 

Cheers

Robin 

A real type Ia supernova beauty. Thanks for posting! With respect to the "Proposed forum name and description change" here are my remarks as a beginner in this field:  Robin's post is exactly what I like to see in this forum: Observational astrophysical measurements that may be a trigger for a  subsequent critical scientific discussion or will spur other observers to reproduce the results with their own equipment. The heart of the scientific method is replicability. If adequate information in the posts is provided on the recording and data reduction steps applied, then the validity of the presented measurements can be verified. Sometimes this open discussion can reveal that you have presented invalid data (see here my great failure to detect polarization:https://www.cloudyni...-comet-neowise/ ) but only in this way you can learn something and improve your skills. Having this said, I would prefer to keep the name "Observational Astrophysics" for this forum while the new description is ok for me.  It would be a pity if the new name would lead to an increase of discussions that are not based on solid measurements (English is not my mother language but I hope the reader can follow my arguments).


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#8 NJScope

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Posted 17 October 2020 - 11:34 AM

Robin:

 

Thanks for posting the spectrum for SN2020uxz which appears to confirm that it is a Type 1a.  Last night's photometry (3 x 90sec) from DBO revealed that SN2020uxz is still brightening (mag 13.72 ±0.01):

Attached Thumbnails

  • SN2020uxz_ClearFilter_FOV.jpg


#9 robin_astro

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Posted 17 October 2020 - 01:28 PM

Robin:

 

Thanks for posting the spectrum for SN2020uxz which appears to confirm that it is a Type 1a.  

Yep an excellent match. The broad Si II 6355A absorption line, the key defining spectroscopic  feature in type Ia is very clear, first shifted to the red by the redshift of NGC514 and then blue shifted by the velocity of the material thrown out (~11000 km/s) so that it ends up here at ~6180A

 

SNID estimates that it is still a few days from maximum

 

Cheers

Robin


Edited by robin_astro, 17 October 2020 - 01:29 PM.


#10 descott12

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Posted 18 October 2020 - 10:42 AM

A spectrum from last night (ALPY 600 8x10min ~12A resolution) overlaid on the best fit from SNID, the supernova identification program (red)

 

attachicon.gif_sn2020uxz_20201015_892_leadbeater_SNID.png

 

 

Cheers

Robin 

Robin,
Awesome spectrum. I see you used 80 minutes of total exposure. What do you think the minimum exposure would be to capture something useful? I have really improved my setup and am now guiding with phd2 so I think I could do an extended exposure but I am also not that patient! 

 

My recent attempts with a few quasars have shown me that patience is definitely required as my 10-12 minute captures all failed to show any spectrum at all.



#11 robin_astro

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Posted 18 October 2020 - 12:39 PM

wWhat do you think the minimum exposure would be to capture something useful? I have really improved my setup and am now guiding with phd2 so I think I could do an extended exposure but I am also not that patient! 

 

Hi Dave,

 

With most faint objects I tend to budget for an hour or so total exposure to get the best SNR (in 10 or 20 min sub exposures).  I don't find much benefit going for more that 2 hours though. (With  the ALPY 600 or LHIRES slit spectrographs the sky background is not normally a limiting factor for me, though it can be with the lower resolution ALPY200 and of course with the slitless Star Analyser). Mag 14 is ok for the ALPY 600 and my C11. The individual 10 min exposures here at mag 14 still show the main features well.

 

sn2020uxz_20201015_892_Leadbeater.png

 

I can go to ~mag 15.5 with the ALPY 600 but with worse SNR. The lower resolution ALPY200 goes lower to around 16.5-17 where the noise contribution from sky background starts to become significant, even with the slit. The limit with the LHIRES at maximum resolution (R~14000) is around mag 10 but limiting magnitudes depend on the SNR you can accept of course.

 

The trick with the Star Analyser on faint targets with broad features like these is to keep the dispersion low to concentrate the spectrum. See this unguided mag 12.5 type Ia here here for example

http://www.threehill.../spectra_31.htm

 

Cheers

Robin


Edited by robin_astro, 18 October 2020 - 12:47 PM.

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#12 NJScope

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Posted 18 October 2020 - 12:58 PM

Today's update suggests that SN2020uxz is approaching or is at maximum brightness ( mag 13.72 ± 0.02 using clear filter) which is essentially the same value as yesterday:

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  • SN2020uxz_Clear Filter_FOV.jpg


#13 havasman

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Posted 18 October 2020 - 01:16 PM

Observed on 10/16, this may have been the easiest SN observation ever. I saw it before catching the galaxy itself and verified the location quickly via the galaxy, the nearby ~mV9.5 star and two ~mV14/15 stars that make the useful pattern. My old skydiving pal and new club member who had never looked through a telescope before also found it certainly and it was his 1st-ever SN.



#14 vakulenko_sergiy

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Posted 21 October 2020 - 01:07 PM

I observed 2020uxz yesterday. Measured 13.4 cV mag.

SN 2020uxz

Edited by vakulenko_sergiy, 21 October 2020 - 01:08 PM.

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#15 NJScope

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Posted 23 October 2020 - 12:52 PM

Maximum brightness (mag 13.69 ±0.01) with a clear filter appears to be steady (mag 13.68 ±0.04) over the past six days.  Since both my imaging sites will be clouded over for the next 2-3 days, I would welcome anyone with clear skies to acquire some clear filter data (n≥3) on this supernova.  A decrease in brightness is expected fairly soon so it would be helpful to capture this moment.  The comparison stars (V-mag) are based on the MPOSC3 catalog (MPO Canopus):

 

C1=15.733

C2=14.975

C3=14.666

C4=14.360

Attached Thumbnails

  • SN2020uxz_23Oct_FOV_v2.jpg


#16 descott12

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Posted 23 October 2020 - 01:14 PM

Maximum brightness (mag 13.69 ±0.01) with a clear filter appears to be steady (mag 13.68 ±0.04) over the past six days.  Since both my imaging sites will be clouded over for the next 2-3 days, I would welcome anyone with clear skies to acquire some clear filter data (n≥3) on this supernova.  A decrease in brightness is expected fairly soon so it would be helpful to capture this moment.  The comparison stars (V-mag) are based on the MPOSC3 catalog (MPO Canopus):

 

C1=15.733

C2=14.975

C3=14.666

C4=14.360

Thanks for the reports. I have been anxiously waiting for a clear night to try to see this and hopefully capture a spectrum.



#17 descott12

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Posted 24 October 2020 - 10:56 AM

Hey All,

I had a look at the SN last night. Amazing how bright it is! I can't imagine experiencing the violence up close!  Anyway, as bright as it was to see, the spectrum was quite dim. I am just learning guiding with phd2 and that is actually going well so I was able to capture 23 minutes of 68 second exposures.

My intensity levels were quite low and swamped by a relatively bright moon and light pollution, but I can almost imagine that I actually captured it.

Is it my imagination or do I have a couple of iron absorptions and the all important Si II at 6150?

 

Regarding the 6150 absorption: That number appears in Walker's reference and in others but that is blue-shifted from the rest wavelength and it should be very much dependent on the objects normal red shift and the blue shift from the explosion itself. So shouldn't resulting number vary in each case?? Or is this just some sort of average overall shifted wavelength?

Thanks

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  • SN2020uxz.png

Edited by descott12, 24 October 2020 - 11:00 AM.


#18 robin_astro

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Posted 24 October 2020 - 02:00 PM

 

Regarding the 6150 absorption: That number appears in Walker's reference and in others but that is blue-shifted from the rest wavelength and it should be very much dependent on the objects normal red shift and the blue shift from the explosion itself. So shouldn't resulting number vary in each case?? Or is this just some sort of average overall shifted wavelength?

 

I think it is just a typical value for nearby galaxies with low redshift (6150A = ~10000km/s at zero redshift)

It actually varies with time as we see deeper into the explosion as the material becomes more transparent. SNID uses this effect to estimate the age from the spectrum.

 

The radial velocity of Si II 6355 and the relative strength of the Si II 6355 and 5972 lines can be used to further classify type Ia supernovae as here for SN 2019ein

http://www.spectro-a...start=30#p12679

http://www.spectro-a...start=30#p12713

http://www.spectro-a...start=40#p12716

 

Cheers

Robin


Edited by robin_astro, 24 October 2020 - 02:08 PM.


#19 descott12

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Posted 24 October 2020 - 02:17 PM

I think it is just a typical value for nearby galaxies with low redshift (6150A = ~10000km/s at zero redshift)

It actually varies with time as we see deeper into the explosion as the material becomes more transparent. SNID uses this effect to estimate the age from the spectrum.

 

The radial velocity of Si II 6355 and the relative strength of the Si II 6355 and 5972 lines can be used to further classify type Ia supernovae as here for SN 2019ein

http://www.spectro-a...start=30#p12679

http://www.spectro-a...start=30#p12713

http://www.spectro-a...start=40#p12716

 

Cheers

Robin

Thanks Robin. That makes alot of sense.
Regarding my spectrum: do you think I have anything real there or is it just noise? I going to try to guide for 60 minutes next time.



#20 robin_astro

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Posted 24 October 2020 - 02:27 PM

Regarding my spectrum: do you think I have anything real there or is it just noise? I going to try to guide for 60 minutes next time.

Yes it is probably real. Can you post a dat file (or send it to me via the email address on my website) ?  I will overlay it on mine and perhaps even put it through SNID

 

or you can pick my spectrum up from the BAA database

 

Cheers

Robin


Edited by robin_astro, 24 October 2020 - 02:28 PM.


#21 robin_astro

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Posted 24 October 2020 - 02:33 PM

You can play with the published spectra on the TNS website to match common lines, entering the galaxy redshift and  the explosion velocity. For example the velocity was ~16000km/s  from the FTS/Floyds spectrum on 2020-10-05 compared with ~11000km/s when I took my spectrum on 2020-10-15  

https://wis-tns.weiz.../object/2020uxz

 

SN 2020uxz_SPRAT_d-15.png


Edited by robin_astro, 24 October 2020 - 02:37 PM.


#22 sunnyday

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Posted 24 October 2020 - 02:35 PM

great work , thanks . 



#23 descott12

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Posted 24 October 2020 - 02:36 PM

Yes it is probably real. Can you post a dat file (or send it to me via the email address on my website) ?  I will overlay it on mine and perhaps even put it through SNID

 

or you can pick my spectrum up from the BAA database

 

Cheers

Robin

That would be great. Here it is. I cropped it down to get below the upload limit but the real data (what little there is!) is intact. Thanks alot

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  • 23_27_58 - STACKED_1 copy.png


#24 robin_astro

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Posted 24 October 2020 - 03:04 PM

Sorry, I meant the digitised data you used to generate your graph, as a .dat or .txt file (2 column, wavelength, intensity)

 

Cheers

Robin


Edited by robin_astro, 24 October 2020 - 03:05 PM.


#25 descott12

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Posted 24 October 2020 - 03:21 PM

Sorry, I meant the digitised data you used to generate your graph, as a .dat or .txt file (2 column, wavelength, intensity)

 

Cheers

Robin

Ah, my EasySpec program that I created imports the image file and does all the processing internally but I haven't added a function to export the formatted data. But that was actually on my to do list. I will add the right away!

Thanks




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