Notices by Kelly Lepo (kellylepo@astrodon.social), page 4

From Andrey Kravtsov, we called our galaxy modeling code GRUMPY. It ends in "PY" because it was written in Python, but mostly it was a forced acronym to honor Grumpy Cat (RIP), but also "we wrote it in 2020 and that was how we were feeling".
#JWSTYearOne

Ok, actual science results from Andrey Kravtsov and GRUMPY. You can use a model designed for nearby dwarf galaxies and use it to fit the earliest galaxies. It works really well, as long as you have random, "bursty" star formation (which is reasonable).

No new physics required; very ancient galaxies follow the same rules as nearby galaxies. JWST has not disproven the Big Bang. #JWSTYearOne

And now we move into the exoplanet part of the afternoon.

Results from Nikku Madhusudhan about exoplanet
K2-18 b. They have the first detection of methane and carbon dioxide in a habitable-zone exoplanet.

Press release: https://webbtelescope.org/contents/news-releases/2023/news-2023-139

#JWSTYearOne

One thing to come out of several talks this morning, is the importance of stellar flares in the Trappist 1 system.

The red dwarf in the Trappist 1 system has several flares per day that are similar to flares that happen once per month on the Sun. This tends to complicate planet transit methods and can cause false detections of molecules if you are not careful.
#JWSTYearOne

A new #JWST view of the remnant of Supernova 1987A. 

SN 1987A has been a target of intense observations at wavelengths ranging from gamma rays to radio for nearly 40 years, since its discovery in February of 1987. Located 168,000 light-years away in the Large Magellanic Cloud, it was the nearest supernova to explode in the era of modern telescopes.

More: https://webbtelescope.org/contents/news-releases/2023/news-2023-136

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#Astronomy #Supernova

The central keyhole structure in SN 1987A is made of clumpy gas and dust ejected by the supernova.

A new feature seen by JWST are small crescent-like structures near the keyhole. They may be a part of the outer layers of gas shot out from the supernova explosion.

A bright, equatorial ring connects two faint arms of the hourglass-shaped outer rings. These structures formed from material ejected before the supernova. The bright hot spots appeared as the supernova’s shock wave hit the ring.

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Here is a #Hubble image of the SN 1987A remnant. We see the same faint, hourglass-shaped rings, pearl necklace-like inner ring of clumps of gas and keyhole shape in the center. What we don't see in this visible-light view are a lot of the other structures in the inner ring that we see with JWST's infrared eyes.

Image from: https://hubblesite.org/contents/media/images/2007/16/2097-Image.html

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@morganism The hourglass-shaped rings (and the inner ring) are from material previously ejected from the star, that glow because they were ionized by ultraviolet and X-ray light from the supernova explosion.

A proposed formation mechanism comes from binary interactions: https://hubblesite.org/contents/media/images/2007/10/2063-Image.html

@morganism During a supernova, the core will collapse until it reaches nuclear densities. At this point, material will continue to fall in, producing a shock that propagates outward — the bounce. This shock releases a burst of subatomic particles known as neutrinos. The energy of the neutrinos tells us about the physics of the bounce.

Before the light from SN 1987A arrived, several neutrino detectors on Earth observed such a burst, in agreement with models.

Fig from: https://doi.org/10.1007/978-3-319-96854-4_12

ESA just released some beautiful #JWST images of M51, the Whirlpool Galaxy.

In the near-infrared image, dark red features trace the filamentary warm dust, while colors of red, orange, and yellow show gas ionized by recently formed star clusters. 

In the mid-infrared image, dust grains and molecules glow, heated by starlight. Empty cavities and bright filaments alternate, giving the impression of ripples propagating from the spiral arms. 

More https://esawebb.org/images/potm2308c/
#Astronomy #Space #Galaxy

Today's #Hubble Favorite is Ruben's galaxy, UGC 2885.

This majestic spiral was named after astronomer Vera Rubin, who studied the galaxy's rotation to find evidence for dark matter.

It's the largest and most massive spiral galaxy in the local Universe. It is 2.5 times the diameter of the Milky Way and has 10 times as many stars.

In this image, stars with diffraction spikes are from our own Milky Way. The brightest photobombs the galaxy's disk.

More: https://hubblesite.org/contents/news-releases/2020/news-2020-01
#Astronomy #Space

Today's #Hubble Favorite.

What appears to be a rather ordinary-looking yellowish elliptical galaxy in Hubble’s visible-light view is Hercules A, one of the brightest objects in the radio light sky. 

#VLA radio observations revealed enormous, one-and-a-half million light-years-long jets, seen here in pink. They are powered by a 2.5-billion-solar-mass black hole in the center of the galaxy.

More: https://hubblesite.org/contents/media/images/2012/47/3110-Image.html
#astronomy #space #galaxy

In this compass view, we can see the visible-light only view and radio only view of the radio galaxy Hercules A. 

From just the visible light image, we would have no clue that the galaxy’s central black hole is spewing out million light-years-long jets. The jets are made from subatomic particles and magnetic fields shot at nearly the speed of light from the vicinity of the black hole.

Something neat happens when you sort stars by color and brightness.

In this visualization of the stars in the globular cluster Omega Centauri, we can clearly see several groups of stars emerge from this sort: normal, main sequence stars; red giants; blue, horizontal branch stars; and white dwarfs. These are all stages in the lifecycle of Sun-like stars.

Download: https://hubblesite.org/contents/media/videos/35-Video
#astronomy #space #stars #hubble

Researchers using #JWST were able to catch an enormous water plume from Saturn’s icy moon Enceladus. The plume is more than 20 times the size of the moon. Enceladus orbits Saturn every 33 hours, spraying water and leaving behind a torus—or “donut”—of material in its wake. 

So movie aliens, if you’re considering invading Earth to steal our precious water, I would suggest taking a detour to Saturn 😉

More: https://webbtelescope.org/contents/news-releases/2023/news-2023-112
#Astronomy #SolarSystem #Space

Researchers used #JWST’s IFU to study the water around Saturn’s moon Enceledus. The IFU (Integral Field Unit) is a combination camera and spectrograph, which captures a spectrum of each pixel in an image.

They detected many lines of water from the torus around Enceladus and the plume itself. In this diagram, white lines are the data from Webb, and the best-fit models for water emission are overlaid in different colors–purple for the plume, green for the moon, and red for the surrounding torus.

Happy #Solstice!

Now is a great time to remind everyone about the #ReasonForTheSeasons.

In other words, why is it cold in the winter and hot in the summer? (1/)

Image Credit: Eirik Solheim https://eirikso.com/2011/01/04/one-year-in-one-image/
#WinterSolstice #WinterSolstice2022

Here is a graph of the average temperatures in Montreal, Canada, in the Northern Hemisphere, Quito, Ecuador, which as the name suggests, is almost on the equator, and Melbourne, Australia, in the Southern Hemisphere.

You should notice a few things:
1) When it is hot in Montreal, it is cold in Melbourne, and vice versa.
2) The temperature at each location shows a predictable, yearly cycle
3) Quito is more or less the same temperature all year round

(2/)

From https://www.worldweatheronline.com/

Let's look at the length of the day in each location:
Dark is night, light is day

Looking at these graphs we notice:
1) When the days are longer in Montreal, they are shorter in Melbourne, and vice versa.
3) Quito has more or less the same amount of sunlight all year long

(3/)

From https://www.timeanddate.com/

Here is a time-lapse of the Earth, as seen from a geostationary satellite. Looking at the Northern Hemisphere, night is on the left and day is on the right.

This matches what we see from the ground. The northern Hemisphere gets more daylight hours for half the year and simultaneously the Southern Hemisphere gets fewer hours of daylight. This reverses after six months. On the equator, the days are always about the same length.

(4/)

Credit: NASA Goddard https://svs.gsfc.nasa.gov/11664