ASASSN-19qv: classical nova (11 mag) in the SMC

Alerts and Monitoring of Novae

ASASSN-19qv: classical nova (11 mag) in the SMC

Postby Robin Leadbeater » Sun Jul 07, 2019 10:25 am

An interesting spectroscopic target for southerly observers

Robin

-----Original Message-----
From: Patrick Schmeer
Sent: Sunday, July 07, 2019 8:31 AM
To: vsnet-alert@ooruri.kusastro.kyoto-u.ac.jp ;
cvnet-outburst@yahoogroups.com ; baavss-alert@yahoogroups.com
Subject: [vsnet-alert 23361] ASASSN-19qv: classical nova (11 mag) in
theSmall Magellanic Cloud

ASASSN-19qv (N)
https://www.aavso.org/vsx/index.php?vie ... oid=838111

SOAR classification of ASASSN-19qv as a classical nova in the SMC:
http://www.astronomerstelegram.org/?read=12907

Complete ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S
and Kochanek et al. 2017PASP..129j4502K) data and light curve:
https://asas-sn.osu.edu/light_curves/47 ... 1771b49249

Multiband photometry and further spectroscopy are strongly recommended.

Clear skies,
Patrick
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
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Re: ASASSN-19qv: classical nova (11 mag) in the SMC

Postby Hamish Barker » Mon Jul 08, 2019 9:05 am

I will have a stab with the star analyser and report back. finding it looks a bit tricky and finding its spectrum at mag 12 on the plate full of SMC stars will be tricky also.
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Re: ASASSN-19qv: classical nova (11 mag) in the SMC

Postby Hamish Barker » Mon Jul 08, 2019 11:36 am

imaging ongoing. have just come in for cup of tea. fricken cold out (zero C maybe, so i guess not that cold but the focus knob feels cold!).

I think i have the nova in test images, right next to gaia 4685624430186064768 (mag 12.76). it's definitely brighter than that. manual dob and dslr so it feels like an achievement.

heading outside, i may be some time... :-)
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Re: ASASSN-19qv: classical nova (11 mag) in the SMC

Postby Hamish Barker » Mon Jul 08, 2019 9:29 pm

stack of 14 x 30 second subs. ( had to throw about 1/4 away as my mount is a dob on unguided equatorial platform.).

Here's a jpg with colours fiddled a bit to balance for a grey background (my camera is a dslr with IR/UV filter removed so everything turns out a bit too red, hence why HD6509 at top left shows pink in the IR part of the spectrum as all three colour filters leak in IR).

Am just processing the binned greyscale fit. Unfortunately there's quite a gradient in the sky and no decent comparison star so it will be hard to make a reliable instrument/sky response correction but I will try with old one and also with the star at top left which is HD6509 (K2/3III) and the right hand star of the bright pair at lower left which is HD6933 (A9IV), which i have in another camera orientation so the spectra don't overlap as they do here.

Even without processing I can see an emission line in blue and in red also. I think the green central peakiness is just my camera's response.

It's quite exciting. I wonder how many other spectra were taken of this star last night.
Attachments
19qv.jpg
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Re: ASASSN-19qv: classical nova (11 mag) in the SMC

Postby Robin Leadbeater » Mon Jul 08, 2019 10:29 pm

A great result Hamish ! The spectrum definitely shows the characteristic Balmer emission of a classical nova. The green band may be unresolved Fe curtain lines. It shows the power of the simple Star Analyser. I suspect this might be the first Star Analyser spectrum of an extra galactic nova

Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
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Re: ASASSN-19qv: classical nova (11 mag) in the SMC

Postby Hamish Barker » Tue Jul 09, 2019 12:22 am

thanks robin!
you are going to laugh when you see a picture of my setup. (galv steel duct tube, plywood dob with equatorial table. various shims to get polar alignment right. reject images due to seeing were various wriggly caterpillar shaped star images...) a nearby neighbour's chimney started puffing out smoke perilously close to my line of sight to the star, so there may be some additional "carbon absorbtion" action in the spectra.

I thought I would reduce it "quickly" with vspec but it keeps crashing at various points. I wish the error tracing in vspec was more thorough so I could work out the actual problem with the software and volunteer to fix it! I will go back to isis.
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Re: ASASSN-19qv: classical nova (11 mag) in the SMC

Postby Hamish Barker » Tue Jul 09, 2019 3:49 am

Due to the gradient across the image I can't get a proper reference for the instrument & airmass response, so have reused one from another day a week or so ago. Similar chilly conditions but probably then was higher altitude so the airmass would have presumably been lower. I have attached a copy of the response curve and my reduced spectrum.

The camera has response down to about 4000A. At the long end, the second order is going to be overlapping below about 8000A but I left it in the chart both as I think one can possibly see the second order of the Hgamma line.
Attachments
uvir-responsehd152235.jpg
uvir-responsehd152235.jpg (64.63 KiB) Viewed 1107 times
nova-asassn-qv19-2019-07-08-1130utc-withheader.jpg
nova-asassn-qv19-2019-07-08-1130utc-withheader.jpg (230.58 KiB) Viewed 1107 times
Hamish Barker
 
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Re: ASASSN-19qv: classical nova (11 mag) in the SMC

Postby Hamish Barker » Wed Jul 10, 2019 12:07 am

I was up late again last night, first trying to extract another response profile from backup images on the same field (overlapping spectra in the nova images were precluding it), then taking reference/ calibration spectra on beta Car (A2IV) at similar airmass (about 2 vs 1.88 for the nova), then going for the nova again. About 30 subs of 30s, haven't reviewed for quality yet, but I expect similar hit rate, maybe 1/2 to 2/3 usable. It was frosty!

I'll post spectra after processing tonight (cloudy today, so hopefully I can make an early night of it!).
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Re: ASASSN-19qv: classical nova (11 mag) in the SMC

Postby Terry Bohlsen » Wed Jul 10, 2019 5:28 am

I haven't had clear skies until last night.
Taken with my LISA R=1500

asassn-19qv_20190709_545_TBohlsen.png


Terry
Terry Bohlsen
Armidale NSW
Australia
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Re: ASASSN-19qv: classical nova (11 mag) in the SMC

Postby Hamish Barker » Wed Jul 10, 2019 11:13 am

nice one terry. What software do you process with? I'm interested to make the erg/cm2/s flux calibration but have not got that far yet.

Here's mine from about the same time. ( my camera date was set wrong but it was about midnight here so I'll say 1200UTC.

I got a much better reference spectrum using beta carina. Maybe a few degrees lower but at least nice and bright and plenty of balmer lines so a better calibration. I'm pretty new to this so forgive the poor quality. i guess even rough data is better than no data.

Should I filter since I am oversampling anyway? I guess I should just bin more to reduce the noise, since seeing and chromatic loss of focus due to the converging beam is anyway limiting my resolution. Or it is better to leave the data as-is?

qv19-2019-07-09-1200utc-nelson.jpg
qv19-2019-07-09-1200utc-nelson.jpg (102.9 KiB) Viewed 956 times
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