APOD: Porphyrion: The Longest Known Black... (2024 Oct 01)

[APOD Robot]

Porphyrion: The Longest Known Black Hole Jets

Explanation: How far can black hole jets extend? A new record was found just recently with the discovery of a 23-million light-year long jet pair from a black hole active billions of years ago. Dubbed Porphyrion for a mythological Greek giant, the impressive jets were created by a type of black hole that does not usually create long jets -- one that is busy creating radiation from infalling gas. The featured animated video depicts what it might look like to circle around this powerful black hole system. Porphyrion is shown as a fast stream of energetic particles, and the bright areas are where these particles are impacting surrounding gas. The discovery was made using data from the Keck and Mayall (DESI) optical observatories as well as LOFAR and the Giant Metrewave Radio Telescope. The existence of these jets demonstrates that black holes can affect not only their home galaxies but far out into the surrounding universe.

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[shaileshs]

Just wondering -

1) What makes this BH so active in spitting out the jet-stream so long (distance), for so long (billions of years) ? Was there so much gas surrounding the BH that was "falling in" (quantity or type way different than other massive BH that are not spitting out such long and strong jet streams) ?

2) Why the "hotspots" at the end are not equi-distant from the "core" ?

3) What made one little "inner hospot" ?

4) If the BH has spit them out billions of years ago, wouldn't the light be super red shifted (and if so, how it was detected by "optical" observatories and not IR observatories) ?

5) Is this BH so isolated that there doesn't seem to be no other galaxy nearby within 23 million light years ?

6) How massive is this BH and how was it formed ?

Thanks in advance to all who provide answers and thoughts.

[Ann]

Just wondering -

1) What makes this BH so active in spitting out the jet-stream so long (distance), for so long (billions of years) ? Was there so much gas surrounding the BH that was "falling in" (quantity or type way different than other massive BH that are not spitting out such long and strong jet streams) ?

2) Why the "hotspots" at the end are not equi-distant from the "core" ?

3) What made one little "inner hospot" ?

4) If the BH has spit them out billions of years ago, wouldn't the light be super red shifted (and if so, how it was detected by "optical" observatories and not IR observatories) ?

5) Is this BH so isolated that there doesn't seem to be no other galaxy nearby within 23 million light years ?

6) How massive is this BH and how was it formed ?

Thanks in advance to all who provide answers and thoughts.

I don't have many answers to offer you, but I can give you some thoughts. I have no idea what made this black hole so active! \_(ツ)_/¯

However, I don't think that this black hole has been so active for billions of years. It is just that these black hole jets existed billions of years ago, not that they have been active for billions of years.

Wikipedia wrote:

The W. M. Keck Observatory on Hawaii was used to show that Porphyrion is 7.5 billion light-years from Earth, and dates to a time when the universe was 6.3 billion years old.

Why are the "hotspots" at the jet ends not equi-distant from the "core" ? You mean, why are the two jets different? I don't think that is strange at all, because is all probability, the intergalactic medium that the two jets met was not the same. After all, consider how different the two jets of nearby giant elliptical galaxy M87 are!

M87 in X-rays and optical light. Credit X-rays: NASA/CXC/CfA/W.Forman et al. Optical: DSS

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M87 in X-rays and radio. Credit: X-ray: NASA/CXC/KIPAC/N. Werner et al Radio: NSF/NRAO/AUI/W. Cotton

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In other words, we can't expect the jets from a black hole to be symmetrical.

So, what made the "inner hotspot"? I have no idea, but after all, the well-known jet from M87 - the one that we can easily observe - has little "hotspots" in it:

M87 optical jet. Credit: NASA and the Hubble Heritage Team (STScI/AURA)

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You asked how we could detect these black hole jets in optical light, even though their light should be super-redshifted. Well, as a matter of fact, the jets were detected in radio waves, which are much, much longer than optical light!

Radio image of Porphyrion, a black hole jet system spanning an estimated 23 million light-years. The Milky Way (assumed diameter: 50 kpc) is shown for scale. Credit: Radio image of Porphyrion, a black hole jet system spanning an estimated 23 million light-years. The Milky Way (assumed diameter: 50 kpc, bottom right) is shown for scale.

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Is this black hole so isolated that there doesn't seem to be any other galaxies nearby within 23 million light years? No, not at all! Consider this illustration of Porphyrion and its surroundings:

Porphyrion and its surroundings. Illustration credit: E. Wernquist / D. Nelson (IllustrisTNG Collaboration) / M. Oei

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All the little orange dots in the illustration above are galaxies!

And finally, how massive is this black hole and how was it formed? I have no idea! But the galaxy where the black hole resides is - or was - ten times more massive than the Milky Way:

Wikipedia wrote:

To find the galaxy from which Porphyrion originated, the Giant Metrewave Radio Telescope in India was used along with ancillary data from the Dark Energy Spectroscopic Instrument in Arizona. The observations pinpointed to the galaxy J152932.16+601534.4, which is about 10 times more massive than the Milky Way.

Bear in mind that we are seeing these jets as they were 7.5 billion years ago. We don't know what the jets are like 7.5 billion years later, if they even still exist, and we don't know what the host galaxy is "today" - although the word "today" is hardly applicable to a galaxy that existed 7.5 billion years ago in a spacetime universe. Bear in mind that space and time are connected in our universe. The galaxy with the enormous black hole jets whose radio light reached us from 7.5 billion years ago has been carried away from us due to the expansion of the Universe, and we have no way of knowing how it has evolved in the last 7.5 billion years. So how can it be meaningful to talk about what this galaxy and this black hole are like "today"? When the "today'" of this galaxy may be beyond the edge of our own light cone of the observable universe?

The observable universe is like a light cone. We can't see what is outside of this light cone. Credit: Astronomicca

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Widely separated points in the larger Universe exist inside their own observable universes. Credit: Study.com

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Ann

[Eclectic Man]

Just wondering -

1) What makes this BH so active in spitting out the jet-stream so long (distance), for so long (billions of years) ? Was there so much gas surrounding the BH that was "falling in" (quantity or type way different than other massive BH that are not spitting out such long and strong jet streams) ?

2) Why the "hotspots" at the end are not equi-distant from the "core" ?

3) What made one little "inner hospot" ?

4) If the BH has spit them out billions of years ago, wouldn't the light be super red shifted (and if so, how it was detected by "optical" observatories and not IR observatories) ?

5) Is this BH so isolated that there doesn't seem to be no other galaxy nearby within 23 million light years ?

6) How massive is this BH and how was it formed ?

Thanks in advance to all who provide answers and thoughts.

I don't know the answers, but I suspect that the reason the jets appear to be different lengths (your question [2]) could have something to do with the interstellar and intergalactic medium through with they are travelling being slightly different and providing slightly differing levels of resistance. The apparently shorter jet also has in intermediate hotspot, the cause of which may have slowed it down somewhat.

My own question is how such long jets are so straight. This suggests (to me, at least) that the mechanism producing them is very stable and has had minimal 'wobble' for billions of years

[Christian G.]

There are jets, and then there are jets, and then there are the Porphyrion jets! 23 million ly, incredible… Does such a jet system tell us that the host galaxy must also be gigantic, or not necessarily? I wonder how it compares to supergiant IC 1101 which according to this image dwarfs M87, jets included!

Fernando de Gorocica

edit: I see that Ann's post above has already answered my question regarding the host galaxy (152932.16+601534.4, just rolls off the tongue)

[equiprx]

Couldn't the difference in length be attributed to the direction the BH is traveling?

[Chris Peterson]

Couldn't the difference in length be attributed to the direction the BH is traveling?

Only if there is a significant density in the interstellar medium... which would also mean that variations in that density could create differences (as noted above).

[gv@milvius.com]

The description says that the black hole was active "billions of years ago". And the jets, now, are a mere 23 million light years long. That seems to imply a velocity much less than 1% of the speed of light. But jets from supermassive black holes are usually relativistic. Why are these jests so slow?

Mmmhhh. Perhaps the comment simply implies that the whole system (black hole and jets) is at a large distance from Earth and, therefore, the light has taken billions of years to get to us.

Any thoughts?

[Chris Peterson]

The description says that the black hole was active "billions of years ago". And the jets, now, are a mere 23 million light years long. That seems to imply a velocity much less than 1% of the speed of light. But jets from supermassive black holes are usually relativistic. Why are these jests so slow?

Mmmhhh. Perhaps the comment simply implies that the whole system (black hole and jets) is at a large distance from Earth and, therefore, the light has taken billions of years to get to us.

Any thoughts?

The latter. The system as we're seeing it is likely only a few tens or hundreds of millions of years old, consistent with relativistic jets of that length.

[MikeA]

If the 2 jets are together 23 million light years long, the ejection must have lasted at least 11.5 million years. Surely in that time, and in the billions of years it has taken for the light to reach us, some sort of gravitational effect or even the expansion of the universe would have distorted their shapes. Even assuming their source to be absolutely stable, why are they so straight?

[Chris Peterson]

If the 2 jets are together 23 million light years long, the ejection must have lasted at least 11.5 million years. Surely in that time, and in the billions of years it has taken for the light to reach us, some sort of gravitational effect or even the expansion of the universe would have distorted their shapes. Even assuming their source to be absolutely stable, why are they so straight?

The billions of years for the light to reach us are irrelevant. We're seeing jets that are at least 12 million years old, and may be two or three times longer than that (I'm not sure if the actual speed of the jets is known). The mechanism that allows them to remain coherent remains uncertain.