Speaker 1: Welcome to Bedtime Astronomy. Explore the wonders of the cosmos
Speaker 1: with our soothing Bedtime Astronomie podcast. Each episode offers a
Speaker 1: gentle journey through the stars, planets, and beyond, perfect for
Speaker 1: unwinding after a long day. Let's travel through the mysteries
Speaker 1: of the universe as you drift off into a peaceful
Speaker 1: slumber under the night sky.
Speaker 2: Imagine you walk into a preschool, right, and you see
Speaker 2: a group of toddlers, and these toddlers are just, you know,
Speaker 2: casually assembling a perfectly functional, high performance Formula one engine.
Speaker 3: Oh wow, Yeah, that would be well terrifying, honestly, right.
Speaker 2: You wouldn't just be surprised. You would immediately assume that,
Speaker 2: like everything you knew about human development, cognitive milestones, and
Speaker 2: basic physics was just completely wrong.
Speaker 3: You'd be looking at this highly complex finished product in
Speaker 3: an environment where honestly, only raw, uncoordinated materials should even exist.
Speaker 2: Exactly, and today we are looking at the cosmic equivalent
Speaker 2: of that Formula one engine.
Speaker 3: It's a massive paradigm shift.
Speaker 2: It really is. I mean, we are taking you, the listener,
Speaker 2: eleven point five billion years into the past. We're looking
Speaker 2: at the universe when it was just a mere toddler
Speaker 2: only about two billion years.
Speaker 3: Old, which in cosmic terms is practically infancy, right, And.
Speaker 2: The object we are examining today is designated EIGHTYF twenty
Speaker 2: two point a one or sometimes just eighty F twenty
Speaker 2: two point one.
Speaker 3: Yeah, both get used in the literature.
Speaker 2: And the sheer existence of this galaxy, with its majestic,
Speaker 2: highly ordered spiral structure and spinning of these staggering speeds,
Speaker 2: it just completely breaks the established timeline of cosmic evolution.
Speaker 3: It really does. I mean, the timeline of galaxy formation
Speaker 3: has been anchored for decades by this idea called the
Speaker 3: hierarchical merging paradigm.
Speaker 2: And that's basically the idea that the early universe was
Speaker 2: just a chaotic, violent place.
Speaker 3: Right right exactly. Early galaxies were expected to be well, irregular,
Speaker 3: just clumpy, messy block of gas and young stars smashing together.
Speaker 2: Like a cosmic demolition derby.
Speaker 3: Yeah, that's a good way to put it. Building a stable, massive,
Speaker 3: rotationally supported disc something like our modern Mochy way that
Speaker 3: was supposed to take billions of years.
Speaker 2: Because it requires slow accretion, violent collisions, and then this
Speaker 2: gradual settling of angular momentum.
Speaker 3: Right, So we definitely did not expect to find a massive,
Speaker 3: beautifully structured pinwheel galaxy sitting right there in the immediate
Speaker 3: aftermath of the universe's formative epic.
Speaker 2: It's wild eighty F twenty two point a one forces
Speaker 2: a total re evaluation of how quickly the universe can
Speaker 2: organize mass and energy.
Speaker 3: It really shows us that highly sophisticated structures can form
Speaker 3: incredibly early on.
Speaker 2: Okay, let's unpack this because going from the expectation of
Speaker 2: chaotic blobs to discovering a highly ordered, barred spiral in
Speaker 2: the Toddler universe, that's a massive shift in our understanding
Speaker 2: of physics.
Speaker 3: You had shift.
Speaker 2: Yeah, But before we get into the structural mechanics of
Speaker 2: how ADF twenty two top a one built itself without
Speaker 2: being destroyed by collisions, we really need to address why
Speaker 2: it took us so long to find it.
Speaker 3: That's a great question because it is massive.
Speaker 1: Right.
Speaker 2: If this thing is so huge, why didn't we see
Speaker 2: it earlier? I mean, we've had the Hubble space telescope
Speaker 2: staring to the deep field for decades now.
Speaker 3: Well, the simple answer is that Hubble was fundamentally blinded
Speaker 3: by the very nature of these specific early.
Speaker 2: Galaxies, blinded how like by the distance no by dust.
Speaker 3: ADF twenty two dot a one falls into a category
Speaker 3: we call dusty star forming galaxies or dsfgs.
Speaker 2: Ah. Okay, the dust is the key.
Speaker 3: Yeah, these are systems undergoing star formation at rates that
Speaker 3: are just almost incomprehensible by our local standards.
Speaker 2: What kind of rates are we talking about here?
Speaker 3: We're talking about hundreds, sometimes even thousands of solar masses
Speaker 3: being converted into stars every single year.
Speaker 2: Wow. And just for context, the Milky Way produces what
Speaker 2: maybe one to three solar masses a.
Speaker 3: Year, exactly just a handful. So ADF twenty two dot
Speaker 3: a one is an absolute monster in comparison.
Speaker 2: But the byprod of all that rampant star formation is
Speaker 2: an immense amount of interstellar dust right right.
Speaker 3: The massive short lived O and B type stars in
Speaker 3: these early galaxies, they basically explode as supernovae very quickly, and.
Speaker 2: Those explosions enriched the interstellar medium with heavier elements.
Speaker 3: Yeah, and those elements condense into microscopic dust grains. It
Speaker 3: creates this incredibly thick cosmic.
Speaker 2: Fog, and dust is incredibly efficient at absorbing short wavelength light.
Speaker 2: So all that ultraviolet and optical light pouring out of
Speaker 2: those young hot stars just hits the dust and scatters.
Speaker 3: Right, Because the wavelength of that light is roughly the
Speaker 3: same size as the dust grains themselves, it's essentially blocked.
Speaker 2: So when Hubble looked at these early epochs, it couldn't
Speaker 2: see the underlying stellar architecture at all. Because Hubble is
Speaker 2: primarily an optical and near infrared observatory.
Speaker 3: Exactly, it's all only the leakage. Hubble would capture a
Speaker 3: few irregular, clumpy patches of rest frame ultraviolet light that
Speaker 3: just happened to escape.
Speaker 2: Through thinner, less dense regions the dust clouds.
Speaker 3: Yeah, and this observational bias actually fed the old paradigm perfectly.
Speaker 2: Oh, I see. Because astronomers only saw messy, disjointed clumps
Speaker 2: of light, they naturally concluded that the galaxies themselves were
Speaker 2: messy disjointed clumps.
Speaker 3: Right. We were looking at the uneven surface of a
Speaker 3: thick fog bank, and just assuming that the terrain underneath
Speaker 3: was just as irregular.
Speaker 2: That's a brilliant way to picture it. So to pierce
Speaker 2: that fog, we needed to move entirely out of the
Speaker 2: optical spectrum.
Speaker 3: We needed observatories operating at wavelength that simply ignore the dust.
Speaker 2: Entirely, which brings us to the pairing of the James
Speaker 2: web Space Telescope and ALMA, the Atacoma Large Millimeter submillimeter Array.
Speaker 3: This is where the technology finally caught up to the physics.
Speaker 3: Let's start with JWST, right.
Speaker 2: Because JWST is designed specifically to capture longer wavelength infrared light.
Speaker 3: Yeah, and because those infrared waves are physically longer than
Speaker 3: the diameter of the cosmic dust grains, the light just
Speaker 3: passes right through the fog.
Speaker 2: It's like having X ray vision for dust. JWST's near
Speaker 2: infrared camera in IRCAM essentially allows us to see the
Speaker 2: actual distribution of the older, cooler stars exactly.
Speaker 3: It reveals the true structural skeleton of the galaxy. But
Speaker 3: while JWST gives us the stellar mass distribution, it doesn't
Speaker 3: give us the kinematics.
Speaker 2: Right. It shows us where the stars are, but not
Speaker 2: how the raw material is moving.
Speaker 3: Yeah, and that is where ALME comes in. LMA operates
Speaker 3: in the submillimeter regime.
Speaker 2: Specifically looking at wavelengths around eight hundred and seventy micrometers
Speaker 2: for this object right correct.
Speaker 3: At those wavelengths, Alia is passive. It's capturing the thermal
Speaker 3: emission of the warm dusk greens themselves.
Speaker 2: And it also picks up specific emission lines of cold
Speaker 2: molecular gas and ionized atoms.
Speaker 3: Right for eightf twenty two dot a one. Al MA
Speaker 3: was tuned to track a very specific signature, the fine
Speaker 3: structure emission line of ionized carbon.
Speaker 2: Also known as the CII emission line.
Speaker 3: Yeah, carbon is distributed throughout the interstellar medium of these galaxies.
Speaker 2: And when the electrons in these carbon atoms drop from
Speaker 2: higher energy state to a lower one, they meet a photon.
Speaker 3: Exactly, a photon with a very specific resting wavelength of
Speaker 3: about one hundred and fifty eight micrometers.
Speaker 2: Wait. I see a major challenge here, though, Okay, what
Speaker 2: is it? If JWST is mapping the infrared light from
Speaker 2: the stars and ALMA is mapping the submillimeter emission from
Speaker 2: the ionized carbon gas, how do we know they are
Speaker 2: looking at the exact same physical structure?
Speaker 3: Ah, the alignment problem.
Speaker 2: Right. In a crowded early universe, a line of sight
Speaker 2: could easily pass through a random cloud of gas in
Speaker 2: the foreground before hitting a galaxy in the background.
Speaker 3: It absolutely could.
Speaker 2: So if you just lay the two images on top
Speaker 2: of each other, how do you mathematically prove the alignment
Speaker 2: is real and not just an optical illusion of the perspective?
Speaker 3: That requires really rigorous astrometric calibration. Astronomers don't just blindly
Speaker 3: overlay the images.
Speaker 2: And hope for the best, okay, So what do they do?
Speaker 3: They use a shared reference frame. Typically it's tied to
Speaker 3: the International Celestial Reference System.
Speaker 2: So they find common points in both images.
Speaker 3: Exactly in the fields observed by both telescopes, there are
Speaker 3: point sources, usually quasars or well characterized background objects.
Speaker 2: And these objects emit strongly in both near infrared and
Speaker 2: submillimeter wavelengths.
Speaker 3: Right by aligning the absolute coordinates of those known reference
Speaker 3: points down to fractions of an arcsecond, you can lock
Speaker 3: the two maps together.
Speaker 2: The gas from LMA and the stellar light from JWST
Speaker 2: are perfectly registered.
Speaker 3: Yes, And when that precise astrometric overlay was performed for
Speaker 3: eighty F twenty two dot A one, the spatial distribution
Speaker 3: of the gas matched the stellar morphology perfectly.
Speaker 2: So it definitely wasn't a foreground cloud. The ionized carbon
Speaker 2: was dynamically bound to the stellar disc.
Speaker 3: It was a single cohesive object, no doubt about it.
Speaker 2: And once that alignment is locked, the image that emerges
Speaker 2: is just breath taking. We strip away the cosmic fog
Speaker 2: and we don't see a blob, no blog at all.
Speaker 2: We see a giant, rapidly rotating barred spiral disc. It
Speaker 2: has a clear spiral distribution of stars, a central elongated
Speaker 2: barlike feature spanning the core, and massive clumpy arms.
Speaker 3: That's beautiful. Yeah, but the visual is really only half
Speaker 3: the story here, right.
Speaker 2: The physical properties are truly defy the models. Let's look
Speaker 2: at the numbers. The Snellar disc is roughly twice the
Speaker 2: size of typical galaxies from that exact same era right.
Speaker 3: At redshift zev round three, and the median stellar mass
Speaker 3: sits at a log of m star over msun greater
Speaker 3: than ten point eight.
Speaker 2: Translating that log rhythmic scale for you listening, we are
Speaker 2: looking at a stellar mass well in excess of sixty
Speaker 2: billion times the mass of our Sun.
Speaker 3: And that is just the mass locked up in the stars.
Speaker 3: That's not even accounting for the dark matter halo or
Speaker 3: the vast reservoirs of gas.
Speaker 2: That's insane for a galaxy to have converted that much
Speaker 2: raw material into a stable stellar population just two billion
Speaker 2: years after the Big Bang. It places it in a
Speaker 2: rare heavyweight class, it really does.
Speaker 3: But the mass is just the prerequisite for the real anomaly.
Speaker 2: Here, which lies in the kinematics right exactly.
Speaker 3: This goes back to Alma and the ionized carbon emission
Speaker 3: line we were just talking about.
Speaker 2: Because Alima isn't just taking a static picture of the gas,
Speaker 2: it's actually measuring the Doppler shift.
Speaker 3: Correct, we know the rest wavelength of the CII emission line.
Speaker 2: So as Alima observes the disc of EIGHTF twenty two
Speaker 2: dot a one, it detects that the wavelength of light
Speaker 2: coming from one side of the galaxy is stretched or
Speaker 2: red shifted.
Speaker 3: Meaning that specific gas is physically moving away from us,
Speaker 3: and on.
Speaker 2: The opposite side of the disc the wavelength is compressed
Speaker 2: or blue.
Speaker 3: Shifted, which means the gas is approaching us. Right.
Speaker 2: And when you plot these velocities across the spatial plane
Speaker 2: of the galaxy, it generates an isovelocity contour.
Speaker 3: Map, frequently referred to as a spider diagram. The highly
Speaker 3: symmetrical nature of This diagram is the undeniable kinematic signature
Speaker 3: of a coherent, cohesive rotating disc.
Speaker 2: And the velocity of that rotation is what completely breaks
Speaker 2: the models. The Alma data reveals that this massive disc
Speaker 2: is spinning at an incredible five hundred and thirty kilometers.
Speaker 3: Percon It's moving incredibly fast.
Speaker 2: At that speed, the centrifugal force is immense. The outer
Speaker 2: edges of this galaxy are moving so fast that they should,
Speaker 2: by all rights just be flung out into intergalactic space.
Speaker 3: Yeah, they really should be.
Speaker 2: So if the buryonic mass, you know, the sixty billion
Speaker 2: solar masses of stars plus the gas, isn't enough to
Speaker 2: hold it together against that rotational shear, where is the
Speaker 2: gravitational anchor?
Speaker 3: Well, you have to assume the dark matter fraction here
Speaker 3: is incredibly dense to prevent the galaxy from tearing itself apart.
Speaker 2: The dark matter halo is the unseen scaffolding.
Speaker 3: Absolutely, to maintain stability at a rotational velocity of five
Speaker 3: hundred and thirty kilometers per second eightyf twenty two point a,
Speaker 3: one must possess a dynamical mass that far exceeds its
Speaker 3: buryonic mass.
Speaker 2: It's the dark matter providing the deep gravitational well required
Speaker 2: to tether all that high velocity gas and stars.
Speaker 3: Right, But what is truly anomalous is the dynamical state
Speaker 3: of the baryens themselves. How So we quantify it by
Speaker 3: something called the V over signa ratio. That's the rotational
Speaker 3: velocity V divided by the velocity dispersion sigma.
Speaker 2: And velocity dispersion measures the chaotic, random, thermal like motions
Speaker 2: of the stars and gas within the system.
Speaker 3: Right. Yes, so high velocity dispersion means the orbits of
Speaker 3: the stars are highly elliptical, plunging in and out of
Speaker 3: the galactic center in totally random orientations.
Speaker 2: Okay, So for decades, numerical simulations suggested that massive galaxies
Speaker 2: in the early universe would be dispersion.
Speaker 3: Supported, exactly because they were supposed to form through those
Speaker 3: violent mergers we talked.
Speaker 2: About the demolition Derby, Right.
Speaker 3: The kinetic energy of those collisions would be pumped into
Speaker 3: the random motions of.
Speaker 2: The stars, which results in a high sigma and a
Speaker 2: low V. They would be puffy, chaotic ellipticals.
Speaker 3: But eighty f twenty two dot a one has a
Speaker 3: very high V over sigma ratio. It is a rotationally
Speaker 3: supported disk.
Speaker 2: The ordered coherent spinning far out weighs the chaotic buzzing.
Speaker 2: The kinetic energy is highly organized.
Speaker 3: It is which forces a massive logical paradox.
Speaker 2: Honestly, I was just thinking that if this galaxy has
Speaker 2: tens of billions of solar mass of stars, the traditional
Speaker 2: rule book says it must have achieved that mass by
Speaker 2: consuming other galaxies.
Speaker 3: Yeah, hierarchical merging. Small halos of dark matter and gas
Speaker 3: crash together to make larger halos.
Speaker 2: But major mergers are incredibly violent. If a galaxy half
Speaker 2: the size of EIGHTF twenty two but a one slammed
Speaker 2: into it, the gravitational tidal forces would completely scramble the
Speaker 2: orbits of the stars.
Speaker 3: It would completely destroy that delicate, high velocity rotationally supported
Speaker 3: spiral disc.
Speaker 2: It would just leave behind a dispersion supported scrap peep. So,
Speaker 2: how does an object get this massive without getting messy?
Speaker 3: We can actually quantify the absence of that messiness using
Speaker 3: morphological mathematics.
Speaker 2: Okay, so astronomers don't just rely on visual classification.
Speaker 3: No, they analyze the light distribution using non parametric metrics,
Speaker 3: primarily the cirsic index and the GENM twenty coefficients.
Speaker 2: Let's break those down. What is the cirsic profile.
Speaker 3: It basically measures how the intensity of a galaxy's light
Speaker 3: varies with distance from its center.
Speaker 2: So how the brightness fades out.
Speaker 3: Yeah, a c index of n equals one describes an
Speaker 3: exponential profile, and that is the mathematical signature of a
Speaker 3: flat extended disc.
Speaker 2: Okay, what about a higher number.
Speaker 3: An index of n equals four, known as the devocolur profile,
Speaker 3: describes a highly concentrated, steep light distribution.
Speaker 2: Which is typical of a massive dispersion supported elliptical galaxy
Speaker 2: or a dense central bulge built by mergers.
Speaker 3: Right, and when you map the infrared light from JWST
Speaker 3: for ADFU two dot a one, it fits the n
Speaker 3: equals one exponential profile.
Speaker 2: It firmly aligns with a disk profile. It's mathematical proof
Speaker 2: of its shape exactly.
Speaker 3: Furthermore, you have the gene coefficient.
Speaker 2: Wait, isn't that an economics term, like it used to
Speaker 2: track wealth inequality?
Speaker 3: It is, but in astrophysics it's used to measure the
Speaker 3: inequality of pixel slux values in a galaxy image.
Speaker 2: Oh that's clever. So a high gene coefficient means the
Speaker 2: light is highly concentrated in a few bright pixels.
Speaker 3: Yes, which often indicates a dense core or violent localized
Speaker 3: starbursts from a recent merger.
Speaker 2: Okay, and what is the M twenty part of GENM twenty?
Speaker 3: M twenty measures the second order moment of the brightest
Speaker 3: twenty percent of the galaxy's pixels. It acts as an
Speaker 3: indicator of spatial structure.
Speaker 2: So mergers typically produce high Genie and high M twenty
Speaker 2: values because the light is unevenly distributed into multiple clumps
Speaker 2: or tidle tales.
Speaker 3: Right, So by running the pixels through these formulas you
Speaker 3: remove human bias entirely.
Speaker 2: You aren't just looking at an image and saying, well,
Speaker 2: it looks like a disc. You are mathematically proving that
Speaker 2: the distribution of mass lacks the localized spikes and tidal
Speaker 2: distortions that a major merger would inevitably leave behind.
Speaker 3: It classifies cleanly as a late type disc. But as
Speaker 3: you said, if it didn't smash its way to sixty
Speaker 3: billion solar masses, how did it get so heavy?
Speaker 2: Right? Where does the mass come from? If not from collisions?
Speaker 3: Smooth accretion?
Speaker 2: Smooth accretion? Okay, explain how.
Speaker 3: We see that the data from jwst in Lama reveals
Speaker 3: a distinct wavelength dependent size trend, and this provides the
Speaker 3: finger of its growth mechanism.
Speaker 2: Okay, what does a wavelength dependent sized trend actually mean
Speaker 2: for the galaxy?
Speaker 3: Well, when observed its shorter rest frame wavelengths, which trace
Speaker 3: the hot, highly energetic young blue stars, the physical extent
Speaker 3: of the galaxy appears much larger.
Speaker 2: The effective radius is extended.
Speaker 3: Yes. However, when observed at longer wavelengths, which trace the older, cooler,
Speaker 3: lower mass stars, the galaxy is significantly more compact, with.
Speaker 2: The light concentrated heavily in the central regions, so that
Speaker 2: wavelength gradient maps directly to an age gradient.
Speaker 3: Exactly, it is inside outgrowth.
Speaker 2: The core of the galaxy is the oldest region. It
Speaker 2: formed first, and over the past billion years or so,
Speaker 2: generations of stars have lived and died there, choking the
Speaker 2: center with dust.
Speaker 3: But the galaxy isn't just sitting there. It is continuously
Speaker 3: adding mass to its outer edges.
Speaker 2: The younger bluer light is extended because pristine raw material
Speaker 2: is continuously arriving at the periphery of the disc.
Speaker 3: Right it rives, cools, condenses, and ignites into fresh rings.
Speaker 3: Of new star.
Speaker 2: It's expanding its borders outwards smoothly without disrupting the ancient
Speaker 2: established core.
Speaker 3: This continuous, smooth delivery of gas is basically the only
Speaker 3: way to build a massive, rotationally supported disc this early
Speaker 3: in the universe.
Speaker 2: But a galaxy cannot accrete tens of billions of solar
Speaker 2: masses of gas smoothly unless it resides in an environment
Speaker 2: capable of providing that supply chain.
Speaker 3: That's the key. We have to look beyond the galaxy
Speaker 3: itself and examine the broader cosmological scaffolding.
Speaker 2: Because EIGHTYF twenty two but A one does not exist
Speaker 2: in an isolated void. It is located at the center
Speaker 2: of the SSA twenty two protocluster at redshift Z equals
Speaker 2: three point zero nine, and.
Speaker 3: A protocluster is essentially a massive over density of dark
Speaker 3: matter that is in the process of gravitationally collapsing to
Speaker 3: form a galaxy.
Speaker 2: Cluster, which are the largest bound structures in the universe.
Speaker 2: And this SSA twenty two region is.
Speaker 3: Extreme, very extreme. The number density of galaxies in this
Speaker 3: specific volume of space is over ten times the cosmic average, so.
Speaker 2: It's an incredibly crowded neighborhood, but way a crowded neighborhood
Speaker 2: usually means more collisions, more hierarchical merging, you'd think so, yes,
Speaker 2: So if it's surrounded by other galaxies, how is EIGHTF
Speaker 2: twenty two dot a one avoiding the demolition derby and
Speaker 2: pulling in pristine gas.
Speaker 3: By tapping directly into the cosmic web.
Speaker 2: The cosmic web, I love that term, It's very descriptive.
Speaker 3: Cosmological simulations demonstrate that dark matter forms a vast three
Speaker 3: dimensional filamentary network.
Speaker 2: And galaxies and clusters form at the nodes where these
Speaker 2: filaments intersect exactly.
Speaker 3: Now. For a long time, the dominant theory was that
Speaker 3: gas falling into a massive dark matter halo would undergo
Speaker 3: shock heating.
Speaker 2: Creating a spherical halo of hot gas that would slowly
Speaker 2: cool and rain down onto the galaxy.
Speaker 3: Right, But in the highly dense environments of protoclusters in
Speaker 3: the early universe, we see a totally different fluid dynamic.
Speaker 3: We see cold streams cold streams.
Speaker 2: So the gas in the filaments is so dense that
Speaker 2: it doesn't shock heat when it hits the outer boundary
Speaker 2: of the dark matter halo exactly.
Speaker 3: It maintains its low temperature and essentially punches right through
Speaker 3: the hot.
Speaker 2: Halo, delivering a concentrated stream of coal gas directly to
Speaker 2: the central galaxy.
Speaker 3: Yes, and the team that map this, led by Hideki Umihata,
Speaker 3: specifically found these massive inflows of coal gas traveling along
Speaker 3: the intergalactic filaments directly into the core of the SSA
Speaker 3: twenty two protocluster.
Speaker 2: These cold streams are the crucial mechanism for understanding ADF
Speaker 2: two dot A one's extreme rotation, aren't.
Speaker 3: They They are The filaments of the cosmic web do
Speaker 3: not just deliver mass, They deliver angular momentum.
Speaker 2: Because as the cold gas flows along the vast cosmological filaments,
Speaker 2: it carries the inherent rotational energy of the macro structure.
Speaker 3: Yes, because the filament's fee into the galaxy from specific
Speaker 3: offset angles rather than falling straight toward the center, so.
Speaker 2: They exert a torque. It's like perfectly throwing a spiraling
Speaker 2: football or wrapping a string around a top and pulling it.
Speaker 3: That's a perfect analogy. The cold streams of at the
Speaker 3: outskirts of the galaxy, and because they are coming in
Speaker 3: at an angle, they wrap around the existing structure.
Speaker 2: The gas settles into a stable co rotating orbit at
Speaker 2: the periphery of the disk before it even condenses into stars.
Speaker 3: And then that explains the five hundred and thirty kilometer
Speaker 3: per second rotation.
Speaker 2: The galaxy isn't just spinning because of its own localized collapse.
Speaker 2: It is being actively spun up by the torque of
Speaker 2: the intergalactic filaments feeding it.
Speaker 3: It gets its mass and its stability from the exact
Speaker 3: same supply line. It is an incredibly efficient transfer of
Speaker 3: energy and mass from the macrocosmological scale down to the
Speaker 3: galactic scale.
Speaker 2: As long as the cold streams remain intact, the galaxy
Speaker 2: can undergo sustained rapid star formation in its outer disc
Speaker 2: without suffering the structural scrambling of a major merger.
Speaker 3: The environment dictates the morphology entirely.
Speaker 2: It's brilliant physics. But it also dictates a finite life span,
Speaker 2: doesn't it.
Speaker 3: Oh, definitely.
Speaker 2: If the SSA twenty two protocluster is continuously pulling in
Speaker 2: mass and collapsing, the local environment is going to change
Speaker 2: dramatically over time.
Speaker 3: It will that vast spherical dark matter halo we mentioned
Speaker 3: earlier is going to accumulate more and more hot gas.
Speaker 2: Eventually the space between the galaxies, and this protocluster isn't
Speaker 2: going to be empty, It's going to be filled with
Speaker 2: an incredibly dense, superheated plasma called the intracluster medium or ICM.
Speaker 3: Right, and as EIGHTF twenty two dot A one continues
Speaker 3: to move through the deepening gravitational well of the cluster,
Speaker 3: what do you think happens to its delicate cold gas supply?
Speaker 2: It faces a severe hydrodynamical stripping process. The physics of
Speaker 2: ram pressure exactly.
Speaker 3: Ram pressure dictates that as a galaxy moves through the hot,
Speaker 3: dense fluid of the intracluster medium, it experiences a huge
Speaker 3: drag force.
Speaker 2: And the pressure obserted on the cold gas in the
Speaker 2: galaxy's disc is proportional to the density of the ICM
Speaker 2: and the square of the galaxies velocity.
Speaker 3: So, given the massive gravitational acceleration within a forming cluster
Speaker 3: adf twenty two to eat a one will eventually reach
Speaker 3: a velocity where the RAM pressure exceeds the gravitational re
Speaker 3: storing force holding the gas to.
Speaker 2: The disc, meaning the hot intergalactic wind literally scours the
Speaker 2: cold gas right out of the spiral arms completely.
Speaker 3: The gas is stripped away, trailing behind the galaxy in
Speaker 3: a massive tail.
Speaker 2: Leaving the stellar disc entirely depleted of the raw hydrogen
Speaker 2: and molecular gas required to form new stars.
Speaker 3: Furthermore, the sheer mass of the growing cluster halo will
Speaker 3: eventually shock heat the incoming cold streams from the cosmic web,
Speaker 3: cutting off the intercollected supply line entirely.
Speaker 2: So it's a combination of starvation from the severed filaments
Speaker 2: and ram pressure.
Speaker 3: Stripping, yes, and this leads to a rapid permanent cessation
Speaker 3: of star formation. We call this quenching, which means.
Speaker 2: This magnificent five hundred and thirty kilometer per second spiral
Speaker 2: is essentially living on borrowed time.
Speaker 3: It is a spectacular but incredibly brief phase of galactic evolution.
Speaker 2: Because without new hot blue stars being formed in the
Speaker 2: outer disc, the existing massive stars will quickly burn out
Speaker 2: and die as supernovae.
Speaker 3: And all that will be left are the low mass
Speaker 3: cool red stars.
Speaker 2: Current evolutionary tracks suggest that by redshift z equals one
Speaker 2: to two, which is just a few billion years after
Speaker 2: the snapshot we are currently examining EIGHTF twenty two, but
Speaker 2: A one will have lost its spiral arms entirely.
Speaker 3: The disc will fade, the kinematics will likely be altered
Speaker 3: by the increasingly crowded environment, and it will.
Speaker 2: Morph into one of the massive, dead red elliptical galaxies
Speaker 2: that dominate the cores of modern galaxy clusters like Coma
Speaker 2: or Virgo.
Speaker 3: Yeah, and that evolutionary art requires us to fundamentally broaden
Speaker 3: our cosmological context. How so, because EIGHTF twenty two toad
Speaker 3: A one is not a singular anomaly, it is an
Speaker 3: archetype for a newly recognized pathway of early galaxy formation.
Speaker 2: Right Because for a long time, observational astronomy operated on
Speaker 2: the assumption that the Hubble sequence the morphological classification of
Speaker 2: galaxies into Grand design spirals, ellipticals and irregulars only locked
Speaker 2: into place at much lower redshifts.
Speaker 3: After billions of years of chaotic assembly. The early universe
Speaker 3: was thought to be populated exclusively by those irregulars we
Speaker 3: talked about.
Speaker 2: But the combination of JWST and LMA has completely dismantled
Speaker 2: that assumption.
Speaker 3: Once astronomers knew the signature of these cold rotating discs,
Speaker 3: they started finding them wherever the environmental conditions were right.
Speaker 2: So we are seeing a profound paradigm shift backed by
Speaker 2: multiple independent surveys.
Speaker 3: Indeed, for example, at a red shift of z equals
Speaker 3: three point twenty five, roughly contemporaneous with eight f twenty
Speaker 3: two dot a one, astronomers discovered an object known as
Speaker 3: the Big Wheel.
Speaker 2: Another exceptionally massive, kinematically stable rotating discs Yes.
Speaker 3: And in the Spiderweb protocluster redshift z equals two point
Speaker 3: one six. Extensive surveys have revealed a significant population of
Speaker 3: dusty star forming galaxies exhibiting extended stellar.
Speaker 2: Discs undergoing rapid, smooth structural growth driven by accretion rather
Speaker 2: than mergers.
Speaker 3: And we are pushing the timeline back even further.
Speaker 2: Than that, right the Rebel Survey.
Speaker 3: Yes, The Rebel Survey a massive, amim large program. It's
Speaker 3: specifically targeted extremely distant galaxies and found the kinematic signatures
Speaker 3: of cold rotating discs as far back as rich of
Speaker 3: z round seven.
Speaker 2: That is, just seven hundred million years after the Big Bang.
Speaker 2: The universe was barely out of the epoch of realization,
Speaker 2: and it had already figured out how to balance immense
Speaker 2: gravitational collapse with angular momentum to build stable discs.
Speaker 3: The underlying physics of fluid dynamics. Dark matter collapse and
Speaker 3: angular momentum transfer do not require billions of years to operate.
Speaker 2: The universe is incredibly efficient. If a massive dark matter
Speaker 2: halo intersects with cold, dense filaments of the cosmic web,
Speaker 2: it will rapidly funnel that gas into a central rotating disc.
Speaker 3: So the Hubble sequence was established incredibly early in the
Speaker 3: universe's history, provided the local supply chain was impact.
Speaker 2: And our ability to map this early Hubble sequence is
Speaker 2: only going to improve exponentially. We are looking at a
Speaker 2: golden age of kinematic astronomy.
Speaker 3: Unquestionably, the data we have from ALMA right now tracing
Speaker 3: the ionized carbon is revolutionary, but it is just the beginning.
Speaker 2: Because LMA is undergoing continuous band upgrades that will vastly
Speaker 2: increase its correlator bandwidth insensitivity.
Speaker 3: Yes, we will have future observation cycles with JWST providing
Speaker 3: even deeper near infrared integration times to trace the lowest
Speaker 3: mass stars in the outer extremities of these disks.
Speaker 2: But perhaps most exciting are the next generation facilities coming
Speaker 2: online in the late twenty twenties and twenty thirties. You're
Speaker 2: talking about the thirty meter class observatories like the extremely
Speaker 2: large telescope the ELT.
Speaker 3: Exactly, the ELT will provide unprecedented spatial resolution from the
Speaker 3: ground in the near infrared, utilizing advanced adaptive optics to
Speaker 3: correct for atmospheric distortion, so.
Speaker 2: We will be able to resolve the individual stellar clumps
Speaker 2: and bar structures in these early discs with the clarity
Speaker 2: we currently reserve for local galaxies.
Speaker 3: And in the radio regime, The square kilometer Array the
Speaker 3: SKA will transform our kinematic mapping.
Speaker 2: Entirely, because currently tracing ionized carbon is effective, but it
Speaker 2: traces gas that is partially affected by the harsh ultraviolet
Speaker 2: radiation of young stone.
Speaker 3: With the SKA and upgraded ALMA receivers, we will be
Speaker 3: able to conduct deep, high resolution mapping of carbon monoxide CO.
Speaker 2: And COO is basically the holy grail for tracking the
Speaker 2: actual fuel for star formation.
Speaker 3: It is because it exists exclusively in the deepest, coldest,
Speaker 3: most shielded molecular clouds where stars are actually born.
Speaker 2: Right now, CO is incredibly faint and hard to detect
Speaker 2: at redshift z equals three, but next generation arrays will
Speaker 2: allow us to map the precise velocities of the actual
Speaker 2: stellar nurseries. Not just the generalized gas.
Speaker 3: We won't just be looking at the macro rotation of
Speaker 3: the disc. We will be mapping the localized turbulence and
Speaker 3: the exact mechanics of how the gas fragments into stars.
Speaker 2: That's amazing. The integration of high resolution cookinematics, JWST, stellar
Speaker 2: mass mapping, and advanced hydrodynamical simulations will allow us to
Speaker 2: essentially watch the inside out assembly of these massive galaxies
Speaker 2: in high definition.
Speaker 3: We are transitioning from the era of simply fire ending
Speaker 3: these early monsters to the era of precisely reverse engineering
Speaker 3: their construction.
Speaker 2: The hierarchical merging paradigm remains a critical component of cosmic evolution,
Speaker 2: particularly for lower mass galaxies and the late time assembly
Speaker 2: of clusters, but we now know it is not the
Speaker 2: universal rule.
Speaker 3: The early universe was perfectly capable of building highly ordered
Speaker 3: massive structures through smooth filamentary accretion.
Speaker 2: It is a stunning reversal of how we view the
Speaker 2: early cosmos. I mean, we started today looking at a
Speaker 2: universe shrouded in a thick, obscuring dust, a place we
Speaker 2: historically wrote off as a chaotic, messy arena of colliding
Speaker 2: irregular blobs.
Speaker 3: But by looking past the optical spectrum. By aligning the
Speaker 3: infrared stellar map from JWST with the submillimeter kinematic map
Speaker 3: from al May, we revealed eight F twenty two point
Speaker 3: a one.
Speaker 2: A massive barred spiral galaxy boasting over sixty billion solar
Speaker 2: masses of stars locked in a hyper stable rotation of
Speaker 2: five hundred and thirty kilometers per second.
Speaker 3: We saw that bypassed the violent demolition derby of galactic
Speaker 3: mergers entirely.
Speaker 2: Instead, it positioned itself at the nexus of the cosmic web,
Speaker 2: utilizing the cold streams of intergalactic filments to continuously pipe
Speaker 2: pristine gas and angular momentum directly into its expanding outer suburbs.
Speaker 3: It is a masterpiece of fluid dynamics and gravitational.
Speaker 2: Engineering, executing inside out growth while sitting in the densest,
Speaker 2: most dangerous environment in the early universe, destined to eventually
Speaker 2: be stripped of its fuel and retired as a massive elliptical.
Speaker 3: The models of galaxy evolution are being actively rewritten to
Speaker 3: accommodate this kind of efficiency.
Speaker 2: But as we close out our discussion today, I want
Speaker 2: to leave you the listener with a thought that pushes
Speaker 2: beyond the macro scale astrophysics.
Speaker 3: It's an important question to consider.
Speaker 2: We have spent this time marveling at the fact that
Speaker 2: the universe could organize chaotic gas into majestic, perfectly stable,
Speaker 2: rotating spirals billions of years earlier than we ever expected.
Speaker 2: The universe was building complex, ordered environments almost immediately after
Speaker 2: the Big Bang.
Speaker 3: Yes, it was.
Speaker 2: But if the universe doing that on a macro galactic scale,
Speaker 2: what else was it accelerating?
Speaker 3: Stable metal, rich spinning galactic discs are the necessary cradles
Speaker 3: for stellar systems like our own.
Speaker 2: Exactly. They provide the stable orbits and the localized densities
Speaker 2: required for heavier elements carbon, oxygen, iron to forge in
Speaker 2: stellar cores, be ejected by supernovae, and mix into the
Speaker 2: interstellar medium without being blasted away by continuous violent galaxy mergers.
Speaker 3: If these highly ordered, chemically enriching environments existed as early
Speaker 3: as seven hundred million to two billion years after the
Speaker 3: Big Bang, the timeline for everything shifts.
Speaker 2: Could the very first ingredients for complex chemistry, the heavy
Speaker 2: molecules required for life, or perhaps even the early precursors
Speaker 2: to rocky habitable worlds, have been quietly forming and churning
Speaker 2: in the spiral arms of these ancient behemoths. If the
Speaker 2: structural architecture of the universe matured this early, it really
Speaker 2: makes you look up at the night sky and wonder
Speaker 2: exactly how long the dark has been hiding the light.