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PSN at2017gjn in NGC1067 confirmed using ALPY 200

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Robin Leadbeater's picture
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PSN at2017gjn in NGC1067 confirmed using ALPY 200

A confirmation of this PSN as a type 1a using the ALPY200 last night.

Attached is my spectrum (black) overlaid on the best fit from GELATO

This is on the outskirts of ngc1067 currently at ~mag 15 and will probably brighten further over the next few days so could be a good target for a standard ALPY too.

Cheers

Robin

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Nice work ...

Another great SNe confirmation Robin. How many is this now ?

Paul

Robin Leadbeater's picture
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SNe confirmations

Thanks Paul,

That's 6 to date I think, though apart from taking a quick spectrum of the very bright sn2017eaw, I have not really been looking this year so this is the first in 2017. It looks like I have quite a bit more professional competition now though. For example ePESSTO now seems to be submitting half a dozen confirmations a night when it has telescope time.

I was planning to try for another one last night in ngc3172 (at2017gla) but it was so close to the pole (+89.1 deg Dec) that I was literally going round in circles trying to get the mount to point at it ! 

Cheers

Robin

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SNe confirmations

Congratulations, Robin.

This is excellent and valuable work that you are carrying out.

All the best,

Jeremy

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Robin,

Robin,

Congratulations I echo Jeremy's comments.

Regards,

Jack

Essex UK 

Robin Leadbeater's picture
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another 1a ( sn2017gxq in ngc 4964 )

https://wis-tns.weizmann.ac.il/object/2017gxq

This  was discovered by Gaia on 17th  at mag  17 and announced on 28th Sept but was much brighter last night (~mag 15 or perhaps brighter) last night when I took the spectrum and  is still likely to be a few days from max so would be a good early evening standard ALPY candidate.

Robin

Robin Leadbeater's picture
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swift follow up

Just heard that a follow up by Swift was scheduled based on my classification :-)

Robin

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Well done

Well done Robin you have got far to good at this! You also seem to get gaps in the cloud I don't see.

Do you leave the Alpy on all the time or do you swap with your LHIRES III? Also do you have two cameras or do you have to swap one over?

Regards Andrew 

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Excellent

The SWIFT observation is a really nice addition to this, and confirms yet again the increasing importance of small telescope / fast response amateur spectroscopy. With your permission I'd like to use this example in an up and coming presentation that I'm giving on the subject at UWA.

Paul

Robin Leadbeater's picture
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Thanks

Thanks !

@Andrew

I have got quite adept at swapping between the LHIRES and ALPY now. They have separate cameras (Currently the ATK  314 and a stellacam on the LHIRES and ATK428 and ATK16ic-s on the ALPY) and are all wired up so I just have to physically swap them over. The one not in use sits in a box next to the scope. I have even got duplicate 200/600 modules for the ALPY now as well which can be changed over without needing readjustment other than aligning the camera angle. I tend to stick with one setup on any particular night though. 

@ Paul,

Sure, no problem. Let me know if you need any specific graphics, images etc 

Cheers

Robin

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Type IA SN 2017gxq

I follow your spectroscopy with interest, Robin. I've just imaged the SN - the stacked image is on my observing page. Very bright - guesstimate mag 14, when compared with Gaia 1564852608241033472. The SN is clearly visible on individual frames; I will keep lights and darks in case anyone wants them for photometry. Best wishes - David

Robin Leadbeater's picture
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distance to ngc4964

Nice image David. Photometry could be useful. Do you plan to submit it to David Bishop's website? there are no measurements or images for this SNe there yet.

http://www.rochesterastronomy.org/snimages/

Only clouds and bands of rain on this side of the country tonight unfortunately.

I suspect it is close to maximum now and since it is a type 1a I had a go at estimating how bright it should get to at maximum.

According to NED http://ned.ipac.caltech.edu there are no redshift independent distance measurements for ngc4964 but based on the redshift the distance would be ~36Mpc. (Though for a relatively nearby target like this the errors could be high)

Using 36Mpc and an absolute V mag of -19.3 at maximum for type 1a SNe gives an apparent V mag at maximum of ~13.5 (not taking into account any extinction) so your mag 14 guestimate seems reasonable.

Robin

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Photometric measurement

I'd be happy to submit my image and magnitude estimation (CCD, clear filter). I gather you have to go through VSnet to get your obs on the Rochester site, so I've sent a request to be added to the system. I've set a median stacking job going on my laptop during my lunchbreak - I can then use the Aperture Photometry Tool on that image to get a more accurate determination of the SN magnitude, using a couple of comparison stars.

Robin Leadbeater's picture
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images and photometry

I think VSnet takes the photometry data but you can submit an image with or without a magnitude directly to David Bishop,(at least that what I used to do !) 

 dbishopx at gmail.com

Robin

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SN2017gxq

Image now visible via Rochester SNimages site. Carried out photometry and checked it - magnitude came out brighter than I judged by eye, at 13.6. Would be good to image this target again. Perhaps Thu. David

Robin Leadbeater's picture
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bright enough for ALPY 600

That's great David,  topping the brightness charts currently.  It is easily bright enough for the standard ALPY 600 now. Let's hope the promised clear skies turn up on Thursday.

Robin

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sn2017gxq with ALPY600

sn2017gxq was bright enough for the ALPY 600 last night despite the full moon. Here is the spectrum (black) overlaid on the best fit according to SNID     

https://people.lam.fr/blondin.stephane/software/snid/

which predicts it is now just past maximum.

Robin