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Reposted by Niamh O’Sullivan

Planets @ Oxford @oxoplanets.bsky.social · 6d

Great talk by @niamhk12.bsky.social on her talk at the Oxford Astrophysics Early Career Showcase! Teaching us all about supergranulation and the need to understand it in order to detect Earth twins!

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Reposted by Niamh O’Sullivan

Caltech IPAC @caltechipac.bsky.social · 25d

The official number of exoplanets has surpassed 6,000! And you can access data on all 6,007 of them right here at IPAC 📈 🪐

Watch the video & read all about the center of the exoplanet universe (also known as NExScI!) here:
www.ipac.caltech.edu/news/the-nas...

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Niamh O’Sullivan @niamhk12.bsky.social · Sep 8

So excited for this!!!

Terra Hunting Experiment @terrahunting.bsky.social · Sep 8

Today HARPS3 is leaving the nest and migrating south!

Reposted by Niamh O’Sullivan

Baptiste Klein @astroklein.bsky.social · Aug 28

Very excited to share that my new paper has been accepted for publication in MNRAS!
We are applying Doppler Imaging to model the activity signals from the HARPS-N Sun-as-a-star spectra! We show that injected planets can be retrieved with great accuracy!
ui.adsabs.harvard.edu/abs/2025MNRA... 🔭🪐🧪

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Niamh O’Sullivan @niamhk12.bsky.social · Aug 9

Sometimes the world is just beautiful

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Planets @ Oxford @oxoplanets.bsky.social · Jul 4

Congrats to DPhil student Niamh on her incredible talk! Her work on supergranulation is helping to improve our ability to detect Earth like planets around sunlike stars! You can read more of her work here: arxiv.org/abs/2506.23693

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Niamh O’Sullivan @niamhk12.bsky.social · Jul 4

Had a great time at #eprv6 this week! We had a splinter session on supergranulation that led to some great discussions! Thank you to everyone who came!

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Reposted by Niamh O’Sullivan

AstroArxiv @astroarxiv.bsky.social · Jul 1

Measuring the Suns radial velocity variability due to supergranulation over a magnetic cycle. Niamh K. O'Sullivan et. al. https://arxiv.org/abs/2506.23693

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Niamh O’Sullivan @niamhk12.bsky.social · Jul 1

So how long does it take to detect and characterise the supergranulation signal? Using the Fisher information content we show that in 23 nights we can characterise the supergranulation timescale in 10 stars, if we switch randomly between stars every 5 minutes!

Niamh O’Sullivan @niamhk12.bsky.social · Jul 1

We find that the supergranulation timescale is anti-correlated with the Sun’s activity cycle. When the Sun is at solar minimum, the supergranules have a larger timescale! This means that we can’t treat supergranulation as static over the timescales of long baseline RV surveys!

Standard deviation and timescale of supergranulation as a function of year. Compared to the Sun Spot number in the lower panel.

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Niamh O’Sullivan @niamhk12.bsky.social · Jul 1

We look at the HARPS-N quiet Sun RVs, derived using both SDO data and YARARA. We model the range quiet Sun RVs with a GP kernel with 2 aperiodic SHO terms and a white noise term.

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Niamh O’Sullivan @niamhk12.bsky.social · Jul 1

It’s paper day 🎉!! If you are interested in seeing how supergranulation changes over a solar cycle in RVs give it a read! arxiv.org/abs/2506.23693

Measuring the Suns radial velocity variability due to supergranulation over a magnetic cycle

In recent years supergranulation has emerged as one of the biggest challenges for the detection of Earth-twins in radial velocity planet searches. We used eight years of Sun-as-a-star radial velocity ...

arxiv.org

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Niamh O’Sullivan @niamhk12.bsky.social · Jun 30

Excited to be at #eprv6 this week! If you are here and want to talk about supergranulation come find me!

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Niamh O’Sullivan @niamhk12.bsky.social · Jun 27

Had a great time learning all about PLATO and the PLATO-ESP conference in Marseille this week!

Niamh O’Sullivan presenting a slide on how much we need to observe stars to detect supergranulation.

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Reposted by Niamh O’Sullivan

NSF–DOE Rubin Observatory @vrubinobs.bsky.social · Jun 23

Introducing...your sneak peek at the cosmos captured by NSF–DOE Vera C. Rubin Observatory!

Can you guess these regions of sky?

This is just a small peek...join us at 11am US EDT for your full First Look at how Rubin will #CaptureTheCosmos! 🔭🧪

#RubinFirstLook
ls.st/rubin-first-look-livestream

A sprawling, textured field of galaxies scattered across the deep black of space. It is filled with the delicate smudges and glowing cores of galaxies of many shapes, sizes and colors, as well as the bright multi-colored points of stars. The image focuses on a collection of interacting galaxies connected by delicate streams of stars. At top center lies a large elliptical galaxy that is dense and smooth, like a polished stone glowing with golden light. Like delicate spider silk or stretched taffy, these stellar bridges link the large elliptical to the few larger galaxies beneath, evidence of past collisions.

All throughout the image, thousands of galaxies gather in clusters or are spread throughout, like glittering gems strewn on a table. Some are sharp-edged and spiral, like coiled ribbons; others round and diffuse, like polished pebbles. Still others are just smudges of various colors against the black of space. The background is peppered with pinpoint stars in reds, yellows, and blues, crisp against the velvet black.

A cosmic tapestry of glowing tan and pink gas clouds with dark dust lanes. In the upper right, the Trifid Nebula resembles a small flower in space. Its soft, pinkish gas petals are surrounded by blue gas, and streaked with dark, finger-like veins of dust that divide it into three parts. It radiates a gentle, misty glow, diffuse and soft like the warmth of breath on a cold hand. To the lower left, the much larger Lagoon Nebula stretches wide like a churning sea of magenta gas, with bright blue, knotted clumps sprinkled throughout where new stars are born. Both nebulae are embedded in a soft tan backdrop of gas that is brighter on the left than on the right, etched with dark tendrils of dust and sprinkled with the pinpricks of millions of stars.

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Reposted by Niamh O’Sullivan

M A Osborne @maosbot.bsky.social · Jun 21

Don't sleep on Gaussian processes. Most under-rated model class on this or any other planet (we've used Gaussian processes to study exo-planets!)

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Reposted by Niamh O’Sullivan

Dr Jake Taylor @astrojake.bsky.social · May 28

Spent the evening at @wolfsonoxford.bsky.social learning about astronomy in ancient Mesopotamia! It was fascinating!

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Niamh O’Sullivan @niamhk12.bsky.social · May 28

We had a great talk by @moudhy.bsky.social at @wolfsonoxford.bsky.social AstroClub this evening! Thank you so much to everyone who came along and especially to Moudhy for such a great talk!

Halley’s Comet and recordings of the comet from 164 BCE

Calculations of distance travelled by Jupiter from ancient clay tablets

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Terra Hunting Experiment @terrahunting.bsky.social · May 28

... and the picture of the grism in its holder just before installation - how beautiful is this?!

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Niamh O’Sullivan @niamhk12.bsky.social · May 28

Come join us if you are interested in astronomy, history, or both! Should be a great event!

Wolfson College Oxford @wolfsonoxford.bsky.social · May 28

Tonight in the LWA, @moudhy.bsky.social will discuss the nightly astrological observations of scholars from ancient Assyria and Babylonia, sometimes interpreted as divine messages about forthcoming events. Hosted by Wolfson AstroClub, not to be missed! 🔭 🌠

www.wolfson.ox.ac.uk/event/readin...

Reading the "Heavenly Writing": Observational astronomy in ancient Assyria and Babylonia - Wolfson College

A Wolfson AstroClub talk offering a survey of the works left behind by early astronomers, followed by telescope observing.

www.wolfson.ox.ac.uk

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Niamh O’Sullivan @niamhk12.bsky.social · May 1

Happy May Morning from Oxford 🌸 🌺🌻

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Niamh O’Sullivan @niamhk12.bsky.social · Apr 23

93 years old and an incredible speaker

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Niamh O’Sullivan @niamhk12.bsky.social · Apr 23

Quite the venue for #Discuss2025!

Oxford town hall, with slide on the criteria for a good solvent life

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Emily Hunt @emily.space · Apr 17

Reading more about this, I'm disappointed in the authors of this study & how they've turned a very marginal result into worldwide press releases.

In this climate, we as scientists have a responsibility to lead by example and represent our work accurately to the press. This is not that. ☄️🔭🧪

Chris Lintott @chrislintott.bsky.social · Apr 17

An astonishing headline reporting on new observations from a team led to Nikku Madhusudhan claims they’ve found ‘hints of life’ on a planet orbiting a dwarf star some 124 light years away. What’s going on? (1/n) www.bbc.co.uk/news/article... 🔭 🧪

Promising hints of life found on distant planet K2-18b

Scientists find new but tentative evidence that a faraway world orbiting another star may be home to life.

www.bbc.co.uk

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Niamh O’Sullivan @niamhk12.bsky.social · Apr 9

Hello!

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