Supernova Host Herding

Announcement(1/25/26)

Whats up citizen scientists! Itʻs been a while since that last check in so we have some interesting things to talk about from these last few months. Also, we plan to have more data up sometime in the next month. We are still amazed by the engagement during these past couple months. So we will try our best to get more pretty galaxies ready for classification.

SN Host Herding went to AAS

The American Astronomical Society hosts two meetings every year, and Supernova Host Herding was a subject of presentation this past winter in Phoenix, Arizona! We have no doubt that all the amazing engagement played a significant role in this appearance! Check out some of the presentation slides here!

130+ Merger Supernovae

80+ Disturbed Supernovae

Thanks to all the amazing work, we have identified more than 130 merger systems hosting supernovae! And even more interesting galaxies are on the way as the most recent round of data is processed. We threw together a collage of some very pretty galaxies below.

Distubed Galaxies

Merger Galaxies

Sibling supernovae?

Some of you may have noticed that some of the galaxies look almost exactly the same.. Doesn’t that seem a bit strange? We can actually confirm that there are sibling supernovae in this dataset! Sibling supernovae are supernovae which share the same host galaxy. Having an active merging system which produces more than 1 supernova in the modern timespan of these images (1980-2026) is amazing! These special systems are not a specific focus of our research, but we think this is really cool! So, we created a small collection of some sibling supernovae which can be found here.

Announcement(10/5)

Sorry for the periodic downtime over the weekend -- you’ve all classified the existing data faster than we thought possible! But don’t worry, there are many more supernovae in mergers to find, and we are going to continue adding more data to this project for the foreseeable future. A new set of recent supernovae is available now!

Here are some merger systems classified this Week!

Here are some disturbed systems classified this week!

Below are the preliminary results

This first plot shows supernovae types by host system, and displays supernova type ratios in one place. The data is showing us there there seems to be a significantly higher ratio of type II supernova in Merging and Disturbed Galaxies. However, the most interesting part of this plot is the green bar all the way on the right, which may be skewing towards a higher ratio of type Ib/c supernovae in these disturbed systems! One possible reason this is occurring is that many of these "disturbed" galaxies might be late-stage mergers.

This second plot is a ratio of the numbers of Type Ib/c versus type II supernovae, where we would expect to see a high ratio in blue or green, but as of now the data suggests no statistical significance.

In the coming weeks, we hope to also look at the luminosities of these supernova explosions and the metallicities of their host environment compared to non-mergers. This will tell us about how turbulence and star formation are changing the numbers of massive stars that form, the properties of those stars, and whether those massive stars are retaining their outer hydrogen envelopes late into their lives.

Announcement(8/25)

A very big thank you to all the beta testers who tried the project and gave feedback!
So far, you have finished classifying 213 objects (which were all the objects in this initial set). We have now added about 900 more objects.

From the preliminary results, 32 objects have been classified as mergers (see below for examples), and 7 of the classified galaxies had disturbed morphologies.

Some Merger Galaxies from the Dataset

Some Disturbed Galaxies from the Dataset

Plot of Supernova Type Ratios Across Different Galaxy Systems

Approximately 70% of the Supernovae in this initial set are Type Ia. Interestingly, there is a slightly higher ratio of Type Ib/c supernovae in the disturbed galaxies, but we will need more classifications to make any concrete conclusions.