New Possible Supernova in NGC1365

[pvelez (Pete)]

Does anyone have any more data on this?

Pete

[Terry B]

I've had cloud and thunderstorms every night for a week. Hopefully it clears soon.

[pvelez (Pete)]

Same here - I collected some data on Sunday but I have yet to check it was ok. Otherwise its been decidedly ordinary

Pete

[pvelez (Pete)]

Here's my data from 25 November 2012 - taken with my new ST-10XME:

B - 12.86
V - 12.60
R - 12.67
I - 13.26

This is calibrated.

It looks to me like the V, R and I are dropping but the B is diminishing at a slower rate.

I need to get my 13 year old son to teach me how to use Excel to plot this now.

Overcast in Sydney again - I expect no more clear skies till Friday now

Pete

[Terry B]

Interesting.
All I got last night was 1 x 5 min exposure of its spectra then the clouds rolled in. Too much noise in the image to be of any use though.

[lepton3 (Ivan)]

Got another R-band measurement last night.

R = 12.59 +/- 0.03

It is dimming smoothly. Here's the latest plot.



-Ivan

P.S. The light curve is being updated here.

[rogerg (Roger)]

I'm after tips on graphing the brightness from my 11 observations over this SN.

Perhaps someone who's posting brightness measurements could advise?

Relevant software I have at my disposal:

• Astrometrica
• MPO Canopus
• CCDSoft

I have tried with mixed success with these.

Astrometrica: I can process each image individually but the magnitude given seems to always be 12.0. Plate-solve is fiddly and manual for each image.

MPO: I'm getting index out of bounds errors and floating point errors. I will RTFM if this is the software I should be using...

CCDSoft: I have used the variable star function to attain a list of measured brightness values but don't fully understand the output.

Which should I have a more serious crack at getting accurate results from? Any tips?

Thanks,
Roger.

[pvelez (Pete)]

Roger

I use MPO Canopus - but only to work out the mags without plotting. Will try that later in the weekend when I have time. Might be able to give some more value then

Pete

[pvelez (Pete)]

My results from last night

B - 12.28
V - 12.81
R - 12.90
I - 13.31

I'll practice plotting and then see what I can produce

Pete

[MLParkinson (Murray)]

I've looked at the price of MPO Canopus and it is well within my budget. Can you give me tips on buying a set of 1.25-inch BVIR filters? My hunch is this will be over $1000 so I will think long and hard before making the investment. Obviously the filters need to be of a very high quality. Thanks for the tips. Murray.

[Terry B]

Originally Posted by MLParkinson

I've looked at the price of MPO Canopus and it is well within my budget. Can you give me tips on buying a set of 1.25-inch BVIR filters? My hunch is this will be over $1000 so I will think long and hard before making the investment. Obviously the filters need to be of a very high quality. Thanks for the tips. Murray.

Murray
I have used lots of different software for photometry. I have MPO canopus but don't use it for photometry as I find it somewhat difficult to use.
For most of my photometry I use AIP4WIN which comes with Richard Berry's book. You can buy it from here http://www.willbell.com/aip/index.htm for $99.
The comp star data just comes from the AAVSO database.
Another option is the free software Munuwin http://www.softpedia.com/progDownloa...ad-156287.html
I have played with it and it is OK.
Photometry filters are quite expensive and are not available in Australia (AFAIK)
I have Astrodon filters and they cost US$175 each from Opt. They currently have "Custom Scientific" filters on special at US$150. I assume they would be fine. See here
http://www.optcorp.com/ProductList.a...9-327-1157-863
Cheers
Terry

[Terry B]

Data from 28/11/12
13.066,0.046,B
12.684,0.048,V
12.766,0.026,R
13.224,0.057,I
It is slowly decreasing in brightness.
Spectra is attached for 28th and 30th.
http://www.aavso.org/tmp3/667637308.png

[Glenpiper (Bernard)]

Hi Terry,

I'm happy to see you are still getting spectra of this SN as I've switched my spectrograph back to a high-res mode for another project ... not that the weather is cooperating on that!

Custon Scientific cheaper than Astrodon ... that is a surprise, as CS used to be the more expensive and desirable of the two. I understand that the Schuler BVRIs (once the 'poor man's CS) have improved since Don, of Astrodon, took them over ... so have the tables been turned?

[Merlin66 (Ken)]

Murray, you have a PM

[Greg Bock (Greg Bock)]

Wow guys, it's refreshing to see so much activity around this SN event, and also to follow the emergence of the spectral and photometry data..keep it up!

[lepton3 (Ivan)]

Fascinating to follow the evolution of this supernova. It is moving into a new phase, where the brightness is levelling off. Apparently this feature (I've seen it called the "shoulder" in articles) is commonly seen for type Ia supernovae in the R and longer wavelength bands.

-Ivan

P.S. For the person who was inquiring about filters, FWIW I use Custom Scientific photometric filters and have not had any reason to fault them optically. A minor niggle is that the thread is a bit small for my Orion 5-posn filter wheel. I pack the threads out with teflon tape to get them to sit snugly in the filter wheel.

[lepton3 (Ivan)]

Maybe I have made an error, but tonight my measurement of this SN shows it has brightened by about 0.19 mag.

I've checked the images carefully, and the plate magnitude differs from that of December 5th by only 0.003 mag, so it really does look like it has flared.

On the 5th, it was 12.758 +/- 0.021, tonight (8th) it is 12.571 +/- 0.019.

I am measuring with an R filter. Can anyone confirm/refute?

-Ivan

[lepton3 (Ivan)]

OK, tonight (9th Dec) the measurement is R=12.790 +/- 0.22, which is very nicely in line with the previous measurements, so for now I'm treating the data from last night as erroneous.

But I'm going to go over it again, because I can't see what was wrong with the setup.

-Ivan

[Glenpiper (Bernard)]

Alain Klotz, the pro who discovered this SN, has just posted the following to the Spectro-L forum:


Hello all,

The TAROT photometry continues and I seen that your
spectroscopic follow-up continues also:

http://www.astrosurf.com/aras/survey...2012fr/obs.htm

The maximum of B light is reached on the 2012 Nov.
11.0 (+/-0.5 day). The Delta_m15(B) = +0.77 which
is very slow decay. This last point is important
because it would mean a very large amount of Nickel
produced by the supernova.

Usually, a low value of Delta_m15(B) is correlated
to a high value of the brightness at the maximum
of light which is not the case for 2012fr.
The representative point of 2012fr in
this diagram is well outside the correlation.

So, the supernova begins to become atypic.
It should be a good idea to continue to observe it.
The present magnitudes today are:

B=13.7 V=12.8 R=12.7

The R and V magnitudes are now in the bump phase
which implies you can continue to record spectra
easily for one month more.

Clear skies,
Alain.


__._,_.___

[lepton3 (Ivan)]

The supernova continues along its evolution. This light curve is becoming a long term project -- 53 days in and 23 observing sessions so far.

We seem to be past the shoulder phase and back on to the usual decline. Still plenty bright for accurate photometry, and probably still possible to get spectra for a while yet.

-Ivan