SN 2016bkv

Supernova Type IIn SN 2016bkv

In late 2012, the supernova impostor SN 2009ip in NGC 7259 brightened in an event that had similarities to a Type IIn supernova. During that event we observed bumps in the decline from peak brightness that have been observed in other Type IIn supernovae but have not been well studied. This target is of a similar type. It is also ideal for crowd sourcing the observations because it should be bright and easilly observed by a 6-8 inch telescope.

Supernova SN 2016bkv was discoverd by Koichi Itagaki on March 21 UT. The transient is in the almost face-on sprial galaxy NGC 3184 (z = 0.002). It's spectrum matches a Type II-n SN (ATEL 8859) discovered a few days before its maximum light. Its location appears to coincide with a knot of young star formation visible in Hubble Space Telescope images (ATEL 8861). It was initially identified at V ~ 17.2 and on March 28 UT it was V~14.7. NGC 3184 is a relatively near-by galaxy so we think that this supernova could get as bright as V ~ 14.

If you are observing SN 2016bkv we would like to coordinate with you to ensure the best possible coverage for this object with the least amount of systematic noise between observers. See below for more information.

I want to thank and acknowledge the observers including Alberto Betzler, Andy Cason, Walt Cooney, Tonis Eenmäe, Raymond Kneip, Brad Vietje, and Brad Walter who are participating in this campaign and contributing observations they have made with their own equipment or obtained through there personal iTelescope accounts.

What's New Today

April 20, 2017 UT

• Took deep follow-up images of the galaxy. SN may still be present at low level (not included on plots below).

August 14, 2016 UT

• The target is at a bad position to observe now. We are working on using DAOphot to deconvolve the target from the star adjacent to it in our photometry.

June 7, 2016 UT

• Updated photometry plots.

Photometry

Coordinate with us!

If you are observing SN 2016bkv we would like to coordinate with you to ensure the best possible coverage for this object with the least amount of systematic noise between observers. Your data will remain yours to post on whatever other forum or site you wish. I am OK with people who are coordinating with us posting photometry to the AAVSO of VSNET on your own. As a thank you though, I will when the project is completed, process your data for you and return file with your measurements in the prescribed format that you can upload for credit under your observer ID.

We would like to coordinate coverage, have copies of your images, and include you as an author on any publications that use your data. Email jmart5 _at_ uis.edu (or contact me on the AAVSO website as user UIS01) for more information.

We would like everyone on the project to contribute Johnson V band photometry. The priority on filters after that in order is: Johnson V, Johnson B, Cousins R, Cousins I. For this target we would also like to encourage people to take low resolution spectra with their filter wheel grating (i.e. SA100 or SA200) if they have one.

Comparison Stars

We are using a sequence of comparison stars provided by the American Association of Variable Star Observers (AAVSO) covering the range from V = 16.0 - 10.3. This sequence can be downloaded by referencing chart X16072BFD on the AAVSO's Variable Star Plotter. OR a copy of the chart can be downloaded here.

Worries and Concerns

We are concerned that comparison star 154 on that chart may interfer with aperture photometry of the target even under the very best seeind conditions. We plan to correct for that at a later date.

We are also concerned that a target lies in a bright knot visible in groundbased images of NGC 3184. We will have to wait until the object fades to correct for that.

Crowd Sourcing

Since the size of the field for each telescope varies, we cannot use all of the comparison stars for every image. We will assess the systematic offsets that occur as a result of this and correct for them later in the project. Right now the resulting systemics still exist in the plot below.

Preliminary Photometry

We have been using VPHOT to reduce the photometry from the images. Our calculated statistical errors on the solution range normally from 0.02 to 0.08 magnitudes.

Sources of Data

The data are from the following sources:

• Alberto Silva Betzler (Brazil) using the iTelescope network.

• Andy Cason (Georgia, USA) using his own 10-inch LX200 telescope -or- the iTelescope network.

• Walt Cooney using 50 cm telescope at Sonoita Research Observatory.

• Tonis Eenmae (Estonia) at Tartu Observatory

• Raymond Kneip (Luxembourg) using the iTelescope network.

• Brad Vietje using an Apogee Camera on his CDK-17 telescope.

• Brad Walter using the Mewlon 250 at McMahan Observatory.

Below is a plot of the Johnson V light curve compiled from telescopes iT7, iT11, and iT21 on the iTelescope network. For many of the systems we have contributing, The blending of a nearby star interferes with aperture photometry of the target. These telescopes clearly separate the target from the nearby star and give a good unblended estimate of the target brightness. (SEE NOTE BELOW)