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Kevin Hainline @kevinhainline.bsky.social · 2d

Legally required to point out the Diner in Tom’s Diner is right under NASA’s Goddard Institute for Space Studies, where someone in the crowd during a 1967 talk by John Archibald Wheeler coined the term “black hole.”

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Kevin Hainline @kevinhainline.bsky.social · 2d

talking at carnegie today with an astronomer about infrared selection of AGNs and she said "ah, so, [the technique] is reliable but not complete" and I think I want that as a t-shirt

RELIABLE
BUT NOT
COMPLETE

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Kevin Hainline @kevinhainline.bsky.social · 6d

Oh also I owe a lot to the help of my co-authors @bemiles.bsky.social, @markmarley.bsky.social and @jarron.bsky.social because I’m ostensibly an extragalactic scientist. It’s so great to meet people who know a lot more than you do about anything (it’s a great reason for universities to exist)

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Kevin Hainline @kevinhainline.bsky.social · 6d

Ok, so, I should correct myself: Tucson doesn't get to 120, but Phoenix has gotten up there. So imagine an object the size of Jupiter with an atmosphere the temperature of Arizona desert in the height of summer; *in JADES we could see this object even if it was 4000-5000 light years away.*

Kevin Hainline @kevinhainline.bsky.social · 7d

We find these cold brown dwarfs all over the place in the survey. Some of them are so cold that their surface is about the same as what Tucson can get to in the summer. This object, JADES-GS-BD-5, which we observe with NIRCam and MIRI, has a temperature of 322 K, or only 120° Fahrenheit (49° C)!

Another plot from the survey, showing JADES-GS-BD-5, with the observed data points plotted as black points, and the fit as a squiggly line that matches the observed data points well. The distance we predict from the fit is only 70 parsecs, and the temperature is 322 Kelvin. Beneath the fit plot, there are thumbnails showing the object as seen in different NIRCam and MIRI filters, out to 12.8 microns.

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Kevin Hainline @kevinhainline.bsky.social · 7d

ANYWAY, BROWN DWARFS ARE PRETTY COOL

THIS IS A PLAY ON WORDS YES BUT ALSO THEY ARE COOL IN THE AESTHETIC SENSE

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Kevin Hainline @kevinhainline.bsky.social · 7d

Finally, with our sample and some from the literature, we can look at the number of these very cold brown dwarfs in a given volume of space as a function of both temperature and height above the galaxy. This will help people with modeling the mass of the galaxy, and the distribution of stars!

Two final plots. On the left is the brown dwarf number density (number of brown dwarfs in a given parsec cubed box) as a function of brown dwarf temperature, where multiple surveys show how low temperature brown dwarfs are more common than higher temperature ones. In the right panel we plot the number density against the height above the galaxy midplane, and we see how it drops off, which makes sense since the galaxy midplane is where the stellar density is highest.

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Kevin Hainline @kevinhainline.bsky.social · 7d

We also see more proper motions for these brown dwarf candidates, where they are observed to move between images taken many years apart, which lends support to our claim that these aren't ultra distant galaxies, but much closer brown dwarfs.

Four sets of plots showing "proper motion" for four different brown dwarf candidates. In each set of plots, there are two images of the same brown dwarf, taken separated by a number of years, and the sources move between when the images were taken, which is represented by circles that show the before and after positions.

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Kevin Hainline @kevinhainline.bsky.social · 7d

One interesting result from fitting these sources is that it looks like the brown dwarf atmospheric metallicity seems to decline for sources that are farther from the Milky Way disk, as we might expect, since these brown dwarfs are likely older, forming at earlier times. This is super neat!

A plot showing the best fit NIFTY metallicity for the brown dwarf candidates as a function of height above the galactic midplane, with the points from JADES as black circles, and points from other papers plottedi n grey. They seem to decline at large heights above (or below) the midplane, with median values shown as star points helping demonstrate this decline.

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Kevin Hainline @kevinhainline.bsky.social · 7d

Our fits are from a new fitting code I wrote with (my (former graduate student!) Jake Helton, Near Infrared Fitting for T- and Y-dwarfs, or NIFTY. It's Bayesian, and designed to fit NIRCam and MIRI data for brown dwarf candidates found in photometric data. It's here:

github.com/kevinhainlin...

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Kevin Hainline @kevinhainline.bsky.social · 7d

We find these cold brown dwarfs all over the place in the survey. Some of them are so cold that their surface is about the same as what Tucson can get to in the summer. This object, JADES-GS-BD-5, which we observe with NIRCam and MIRI, has a temperature of 322 K, or only 120° Fahrenheit (49° C)!

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Kevin Hainline @kevinhainline.bsky.social · 7d

I've taken quite an interest in finding these sources, since, with the depth of JWST NIRCam observations, you can find some really faint sources, many of which are stupendously cold. And a number are very distant - thousands of light years from the Earth, outside of the disk of the Milky Way.

A plot from my paper showing the fit temperatures for my brown dwarf sample as little black dots plotted against their temperatures. The sources in my paper are between 300 and 1200 Kelvin, and extend out to 5 - 7 kiloparsecs. There are other sources from the literature, which are closer, generally, and at higher temperatures.

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Kevin Hainline @kevinhainline.bsky.social · 7d

See, it turns out that when you have incredibly deep infrared observations of hundreds of thousands of distant galaxies, sneaking around in these data are these super cold "failed stars," known as brown dwarfs, which are the link between stars and planets.

An artist's rendition of The Sun, which is large and in the upper left, and then a low mass star, which is much smaller, and increasingly red, then a brown dwarf, which is also reddish, and smaller, then the large planet Jupiter, and finally the tiny lil' Earth in the bottom right.

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Kevin Hainline @kevinhainline.bsky.social · 7d

I wrote another paper! And yes it's about brown dwarfs wait don't go anywhere they're really neat

arxiv.org/abs/2510.00111

JADES: An Abundance of Ultra-Distant T- and Y-Dwarfs in Deep Extragalactic Data

Ultra-cool T- (T$_{\mathrm{eff}} \approx$ 500 - 1200 K) and Y-dwarfs (T$_{\mathrm{eff}}$ $\lessapprox 500$ K) have historically been found only a few hundred parsecs from the Sun. The sensitivity and ...

arxiv.org

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Kevin Hainline @kevinhainline.bsky.social · 7d

it's a slow process but we can get it done
maps.app.goo.gl/w8N21QRLemP8...

a photograph of a road south of Tucson, Arizona, from google maps "street view," of a sign indicating the distances to the upcoming "Sahuarita Exits." There are three, Pima Mine Road, in 1 kilometer, Sahuarita Road, in 6 kilometers, and Duval Mine Road, in 12 kilometers. The thing is, the sign is provided in the metric system, this is one of the few roads in America where that is the case.

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Kevin Hainline @kevinhainline.bsky.social · 13d

I went to a tiki bar once and as I came through the door a bartender was bringing a table of Adults a whole tray of Michelob Ultras, that was what they all ordered

why doesn’t the New York Times profile these people every month

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Kevin Hainline @kevinhainline.bsky.social · 21d

www.rottentomatoes.com/m/core

I unashamedly love this terrible movie

The Core | Rotten Tomatoes

Discover reviews, ratings, and trailers for The Core on Rotten Tomatoes. Stay updated with critic and audience scores today!

www.rottentomatoes.com

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Kevin Hainline @kevinhainline.bsky.social · 22d

Today is my birthday, *and* it's a Pythagorean triple, 9 / 16 / 25. This sort of thing really got a lot of Greek mathematicians excited, until they had to reckon with what would happen to the length (c) if (a) and (b) were 1, that awful irrational square root of two.

a blue triangle with sides labelled a, b, and then the hypotenuse is c. There are squares along each side that show how a^2 is 9, b^2 is 16, and c^2 is the sum of 9 and 16, 25. In the top it says a^2 + b^2 = c^2.

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Kevin Hainline @kevinhainline.bsky.social · 26d

his analysis and research is amazing but I actually published six first author papers in the last five years thank you very much

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Kevin Hainline @kevinhainline.bsky.social · 26d

I think he's probably just talking about Yoshi for the NES, the puzzle game. I don't know why he calls this a "sequel," but the game fits the timeline better than Yoshi's Cookie or Yoshi's Island. en.wikipedia.org/wiki/Yoshi_(...

Yoshi (video game) - Wikipedia

en.wikipedia.org

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Kevin Hainline @kevinhainline.bsky.social · 27d

A text from my father after they sat down to watch the video:

A text from my father: “We just watched it. It’s great. Mom kept interrupting and recounting everything as if I knew none of this! And towards the end she said, and I quote, “At the end he should say ‘mom was right’!”

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Kevin Hainline @kevinhainline.bsky.social · 27d

I own a pair of these deep field socks, and they're what I've worn to so many public JWST talks and they always get a great reaction from folks who notice. I might have to pick up a second pair, not because mine have worn out, but just because I love them so much.

Daniel | ScienceSocks et al. @sciencesocks.bsky.social · Sep 8

Let's restock your favorite ScienceSocks! 😎

We need 100 pairs pre-ordered to bring back 5 sold-out designs!

The #JWST #MarsRover #Eclipse and #Lucy socks have been sold out since last year 😢

Pre-order a pair here and please spread the word 🙏
🔗 sciencesocks.co/prod...

🔭🐡🧪🎨

the great sock restock as text over a closeup photo of a sock

closeup of lucy sock design showing the spacecraf on a blue sock.

rover family socks showing mars rovers on an orange sock in a repeating pattern

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Kevin Hainline @kevinhainline.bsky.social · 28d

I'm realizing maybe they're referring to the NES game "Yoshi", which could ... naively? be thought of as a "sequel" to Super Mario World, and lines up in the timeline. en.wikipedia.org/wiki/Yoshi_(...

Yoshi (video game) - Wikipedia

en.wikipedia.org

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Kevin Hainline @kevinhainline.bsky.social · 28d

Why would he go through so much effort to...dupe me? Why wouldn't he send the letter to more people? I've had the letter for *years.* The alternate is that I made it all up, but that would be a dumb/ruinous thing to do for a few hundred YouTube views.

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Kevin Hainline @kevinhainline.bsky.social · 28d

@jparish.bsky.social A number of years ago I stumbled on the story behind A Link to the Past's Chris Houlihan Room, including the letter sent to Chris from Nintendo Power. I finally decided to make a video about it all, in case you're interested.
youtu.be/SY00ri_a9y4?...

Chris Houlihan Is Real

YouTube video by Kevin Hainline

youtu.be

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Kevin Hainline @kevinhainline.bsky.social · 28d

I don't subscribe to many conspiracy theories but I'm one of those people that thinks that this song should be the one called Flamenco Sketches on the album, and vice versa

it's just way too bouncy for a song called All Blues