24 replies to this topic

[rekokich]

Supernova 2019np in NGC 3254, Leo Minor

2019np is a type Ia supernova discovered by Koichi Itagaki on 9 Jan 2019 in NGC 3254 at coordinates RA 10h29m21s, Dec +29°30'38"

NGC 3254 is a Hubble type Sbc galaxy located at the distance of 105 million LY. Its apparent diameter is around 5 arcmin, and apparent magnitude 11.5

The image below is a 4 x 90 sec exposure taken on 12 Jan 2019 with a modified Canon T3i camera, ISO 1600, Meade 8'' ACF telescope, and iEQ30pro mount. The apparent magnitude is approximately 16, increased to 15 by 15 Jan 2019.

In the animation, the image is compared to the DSS2 sky survey image from sky-map.org.

 

[alvarete]

Excelent.
Thanks for sharing

[lynnelkriver]

Thanks for the information!  I'm going to have to check this out. Scott

[twidget]

Looks like a good target, once I get to shoot again, (clouds clouds clouds) if it's still there.  Thanks for the heads-up!!

[twidget]

 

From last night.  87 x 90s lums.  Conditions were such that I normally wouldn't have shot, but wanted to catch this SN at or near peak. Stacked a LOT of frames (50%) that I'd normally toss, even with my relaxed standards.

[twidget]

 

Different stretch to get idea of relative brightnesses of galactic core and SN2019np

[rekokich]

Congratulations, twidget, on the excellent photo. I presume you took the image with your 203mm f/3.9 Newt-astrograph.

In your photo 2019np outshines the entire core of the NGC 3254 galaxy. Compared to the second star on the right, USNOA2 1125-06120763, magnitude 14.2, apparent visual magnitude, m, of 2019np is now about 13.5. Assuming the distance, D, of 32.2 million parsecs (105 million LY), the absolute magnitude, M, of the supernova is given by:

m - M = (5 x logD) -5
M = m + 5 - (5 x logD) = 13.5 + 5 - (5 x log 32.2x10^6)
M = -19.04

The absolute visual magnitude of the entire NGC 3254 galaxy is estimated to be -20.94

[twidget]

Thanks, Rudy! Not a great image, but considering the imaging conditions and my less-than-optimal skills, I'm satisfied with it. I wish I'd been able to get some RGB on it to mix in, but was afraid I'd be wasting my time.

 

Yup, shot with the astrograph, forgot to check collimation prior, got lucky it wasn't off by much.

 

Thanks for doing the numbers! I was wondering about the magnitudes, and was going to check that out today. Do you know if it has reached its expected peak yet? It seems like I read that it was expected to peak around apparent mag of 13 yesterday.

 

I'm always amazed by the fact that one of these explosions can generate as much or more light than it's entire host galaxy, at least the core. That's why I made the second stretch - to prove it to myself!!

 

It didn't clear out here till after midnight last night, and was down around 16 deg F (cold for us here) with some wind, so I didn't shoot. I'll try to shoot it tonight, then try to get enough images over the next few weeks to watch it fade away.

Edited by twidget, 25 January 2019 - 11:30 AM.

[twidget]

PS, If you want the full-res master of the first image (not the crop), to compare mags and such against your image, I can Dropbox it to you.

 

This might be a dumb question, but would the presence of the supernova throw off something like Astrometry plate-solve?

Edited by twidget, 25 January 2019 - 11:29 AM.

[rekokich]

Mike,

 

I took the liberty to process your cropped image with XnView, StarTools, and Neat Image. I think it would make a beautiful print. When I sharpened it with wavelets and fractal flux, NGC 3254 seems to be a barred spiral undergoing tidal interactions with two smaller galaxies along SE and NW spiral arms.

 

I submitted the image to Astrometry.net, and it was solved with no problems.

 

Rudy

 

[rekokich]

Compared to DSS2 survey on skymap.org, the limiting magnitude on your image is better than 19.2

 

[twidget]

Mike,

 

I took the liberty to process your cropped image with XnView, StarTools, and Neat Image. I think it would make a beautiful print. When I sharpened it with wavelets and fractal flux, NGC 3254 seems to be a barred spiral undergoing tidal interactions with two smaller galaxies along SE and NW spiral arms.

 

I submitted the image to Astrometry.net, and it was solved with no problems.

 

Rudy

 

z1.jpg

 

No problem. You did a good job with the image, turned a sow's ear into a purse (of sorts)! Good images of this galaxy are hard to find, for comparison with my image. But, the few good ones do show some disruption to the spiral arm structure, IMO.

 

I figured that Astrometry would solve the image OK, but hadn't tried it. Thanks!

 

Compared to DSS2 survey on skymap.org, the limiting magnitude on your image is better than 19.2

 

z2 L.jpg

19.2?? That's a lot fainter than I'd been assuming!

Edited by twidget, 28 January 2019 - 04:28 PM.

[twidget]

     I have been able to get images of N3254 and SN2019np every night since and including the 23rd, with the exception of the 24th (it didn't clear up until I was getting ready for bed at 2am, so didn't shoot that night). The 26th, all I got was a bunch of 2s and a few 3s lums. The other nights, I nabbed 2s and 90s subs. 

     I am in the process of going through the subs, and making some stacked images. I hope to start putting some of them up later today, or tomorrow. The quality will not be very good, since every one of those nights had poor imaging conditions, such that I normally wouldn't have tried to image.

     I will try again tonight, and any night it looks like I can grab at least 2s lums. I'd like to get enough data on this SN as it fades to plot a graph of the process. It's a shame I didn't try to get some subs on the 24th, when this SN peaked, but, oh well.

[twidget]

     A bit later than I planned, but I can start putting up more images on this SN. I've managed to image it on the 23rd, 25th, 26th, 27th, and 30th. I thought I might get an hour or two on it tonight, but the clouds haven't moved out as forecast. That's a shame, because it's 50deg F outside!!

     This SN actually peaked on the 25th, according to the website RochesterAstronomy.org, at apparent magnitude 13.0. It's still one bright sucker!  The images I will be posting have been fully preprocessed and DBE'd, but no further processing. They were cropped 50% of fullsize.

     I will put each night's images in separate posts.

 

Jan. 23, stack of 5x2s lums  (actually framing/focusing subs, but what the heck, they're still subs) 

 

 

Full-size image here:  https://astrob.in/full/388834/0/

 

 

Jan. 23, stack of 49x90s lums

 

 

Full-size image here:  https://astrob.in/full/388837/0/

Edited by twidget, 02 February 2019 - 12:07 AM.

[twidget]

I need to add that the imaging conditions (seeing, transparency, wind, dewpoint, high thin stuff, LP) in which I shot all my SN subs ranged from subpar to mediocre. So, my images are poor even by my LP-infected standards.

Edited by twidget, 02 February 2019 - 01:18 AM.

[rekokich]

Very nice images with great optics and excellent guiding.

 

The limiting magnitude on your images is indeed around 19.5

 

Edited by rekokich, 02 February 2019 - 02:15 AM.

[twidget]

     Thanks for the thumbs-up Rudy! You have a much higher opinion of my images than I do, but I'm not complaining about your praise. 

 

     I am still amazed every time I look at the first subs of this object as they come rolling out of the camera onto the PC screen, and the SN stands out as clear as can be in even 1 sec subs (if you know where to look) !!! Boggles my mind to realize I'm capturing photons from the "death throes" of an already-dead star ( "You've sucked enough hydrogen blood from your buddy here, Mr. Vampire Star" says Mr. Chandrasekhar, so......BOOM! ), located 10s of millions of lightyears away, practically outshining its whole host galaxy !!

 

     I'll put up the rest of my SN images this afternoon. Or evening  

Edited by twidget, 02 February 2019 - 06:19 PM.

[twidget]

Forgot this image from the 23rd. 

 

Jan. 23rd, stack of 5x120s Ha subs

 

 

 

 

 

Full-size image here:    https://astrob.in/full/388991/0/

 

 

[twidget]

Jan. 25, stack of 46x2s lums

 

Full-size file here: https://astrob.in/full/389020/0/

 

Jan. 25, stack of 40x3s lums

 

Full-size image here: https://astrob.in/full/389021/0/

 

Jan. 25, stack of 49x90s lums

 

Full-size image here: https://astrob.in/full/389022/0/

[twidget]

Jan 26, stack of 58x2s lums

 

Full-size image here:  https://astrob.in/full/389032/0/

 

 

Jan 26, stack of 10x3s lums

 

Full-size image here:  https://astrob.in/full/389033/0/

 

This was the worst night I've imaged the SN. There was a visible layer of thin murkiness drifting above my location, and an actual, thick cloud cover moved in before I could finish my 3s lums run, so I never did get any 90s lums.

[twidget]

Jan 27, stack of 50x2s lums

 

Full-size image here:  https://astrob.in/full/389034/0/

 

Jan 27, stack of 43x90s lums

 

Full-size image here:  https://astrob.in/full/389035/0/

[twidget]

Jan 30, stack of 72x2s lums

 

Full-size image here:  https://astrob.in/full/389038/0/

 

Jan 30, stack of 43x3sec lums

 

Full-size image here:  https://astrob.in/full/389039/0/

 

Jan 30, stack of 31x90s lums

 

Full-size image here:  https://astrob.in/full/389040/0/

 

     The last 3 nights have been unshootable. As of the 30th, it appeared that the SN was still near its peak, on that slightly-downward-sloping plateau on its light curve that Type IA supernovae pass through in the first few weeks after the peak. It appears, by my eyes, compared to that other labelled star that Rudy so welcomely identified for me, as bright as it did on the 25th, which was its peak.

     I really want to be able to image this thing every few days as it starts into the steeper part of the downward side of its light curve, but the weather has to make a drastic turn to the clear side.

[rekokich]

twidget,

Here is photometry data for the region from DSS2, which might help you to plot the light curve. If you are able to take standard exposures, say 20x90'', with constant camera settings, over fairly regular intervals, you might consider making a GIF showing how the SN fades. A transient increase in brightness during the fading phase might suggest the presence of a black hole in the vicinity.
Rudy

 

[twidget]

Rekokich,

 

Thank you for the photometry data! It will come in very handy as I learn how to produce such a light curve, and actually generate one. The GIF suggestion mirrors my thinking (once it does start noticeably fading AND the clouds part).

Edited by twidget, 05 February 2019 - 10:04 AM.

[vakulenko_sergiy]

I also hunted for AT2019np and 2018hna at 19 Jan 2019. Here is my catch. 15x180sec both.

 

AT2019np

 

2018hna