Cosmic Cataclysms

Searching for the fastest optical explosions with TESS

The TESSELLATE Sky Survey

Building a high time resolution, all-sky time domain catalogue

Hugh Roxburgh

with R. Ridden, C. Montilla, B. Leicester,

A. Moore, Z. Lane et al.

OzFink Workshop - 11^th November 2025

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Things We Already Know

• LSST will revolutionise our understanding of the transient sky

… above certain timescales

Brightness

100 days

10 days

1 day

1 hour

1 minute

Core collapse supernovae

Type Ia

Novae

Kilonovae

FELTs

FBOTs

Gamma Ray Burst Afterglows

LSST Discovery Limit

?

The Optical �Time Domain

Lifetime

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Let’s get on the same page

• A large gap at timescales of minutes / hours will remain 🡪 and will pollute broker streams

• TESS has the observation strategy to uniquely complement LSST, providing fast cadence data to illuminate sparse events

• LSST will revolutionise our understanding of the transient sky

… above certain timescales

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Observing with a cadence of 30 minutes 10 minutes 200 seconds!

Observing with a cadence of 30 minutes

Transiting Exoplanet Survey Satellite

Credit: NASA

Observing with a cadence of 30 minutes 10 minutes

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• Entire sky covered �at least twice�🡪 most have at least three months of continuous data

Transiting Exoplanet Survey Satellite

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How we usually use TESS

Transient Occurs

LSST detects + brokers classify

Search for TESS coverage / capture

Science!

1 – 2 months

Targeted Follow-up

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Are there other ways we can use TESS?

TESS Discovery

Fast Transient Occurs

TESS detects

Search for LSST coverage

1 – 2 months

Can we extract any more info from one / a few data points? e.g. colour

Are there things TESS can supply LSST with to help with real time classification?

TESS Supplementation

We need a

blind survey!

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A Reminder

• 7+ years of data�🡪 200+ TB stored in archive �🡪 majority not analysed

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TESS Blind Survey

1. Build a pipeline to reduce

all archival TESS data

2. Detect every variable

event

Dr Ryan Ridden

3. Classify every variable

event

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https://github.com/CheerfulUser/TESSreduce

Credit: Ridden-Harper et al. (2021)

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TESSELLATE

(TESS Extensive Lightcurve Logging and Analysis of Transient Events)

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TESSELLATE

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TESSELLATE

x

y

time

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TESSELLATE

x

y

time

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TESSELLATE

TESSreduce

x

y

time

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TESSELLATE

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TESSELLATE

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TESS

Source

Templates

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TESSELLATE

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Grouping Detections

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• Instrument artifact
• Asteroids
• Stellar flares
• Variable stars
• Supernova/nova
• Cataclysmic variables
• Other?

Endless Detections...

I guess not as bad as LSST…

Cosmic Cataclysms

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Hugh Roxburgh

(PhD, Curtin)

Andrew Moore�(Masters 2024)

Clarinda Montilla

(Masters)

Brayden Leicester

(Masters)

Zac Lane

(PhD)

Armin Rest (STScI)

Ori Fox (STScI)

Rebekah Hounsell (NASA Goddard)

Qinan Wang (MIT, USA)

Dan Muthukrishna (MIT, USA)

Jaime Luisi

(Masters)

Ryan Foley (UC Santa Cruz)

Ashley Villar (Harvard)

Koji Shukawa (JHU)

Rob Sharp (ANU)

Jim Freeburn (Swinburne)

Broader

collaboration:

Jeff Cooke (Swinburne)

Anais Möller (Swinburne)

Michele Bannister (UC NZ)

David Wiltshire (UC NZ)

Michael Albrow (UC NZ)

​

Jolijn Ras

(Honours)

Ajani Grimstrup

(Honours)

Andrii Dzigunenko

(A.A. Prague)

Tait Keller

(Undergrad)

Sansithu Deepagoda

(Lincoln High)

Knisha Hodge

(Honours)

Dr. Ryan

Ridden

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The TESSELLATE Sky Survey

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Classification of Events / Interesting Science

• Variable Stars

• Extragalactic �Transients

glossing over heaps of other stuff, e.g. cool asteroid science (find Brayden) ,

exoplanet discovery , dwarf novae…

Pilot survey data is all 2020 Sectors 27-39 � 🡪 Covers complete southern sky at 10 min cadence

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Variable Stars

• Currently no *good* unified variable star catalogue, especially for fast variables

• …big problem for LSST brokers

�

We can help!

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Run every object light

curve, detect variables

through periodogram

Phase fold about

peak period

Variable Stars - Classification

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Broad classes

Variable Stars - Classification

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Variable Stars - Science

Per sector so far

​

- 10000+ top quality fast variables�(period < 1 day) �

- 20000+ other variables (sample less pure right now)

Catalogue incoming...

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Extragalactic Transients

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Extragalactic Transients – Classification

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Extragalactic Transients – Classification

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Extragalactic Transients – Science

We’re not seeing anything clearly extragalactic…

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Extragalactic Transients – Science

We’re not seeing anything clearly extragalactic…

Unless…

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Extragalactic Transients

Flare Star Catalogue?

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What are some other things you think might be useful? Come find us!

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TESSELLATE Sky Survey (TSS)

Also working in

FRB Cosmology!

A pipeline to detect and categorise all TESS transients

🡪 Processed all Y3 data

Found so far:

• Tens of thousands of variable stars 🡪 catalogue � coming soon
• Thousands of asteroid rotation rates 🡪 catalogue
• Thousands of stellar flares 🡪 some day, a catalogue
• Tens of new exoplanet candidates 🡪 ditto
• No convincing fast extragalactic transients