When real science is more interesting than science fiction. "I have seen things you would not believe, cosmic tsunamis of a black hole moving at 74 million kilometres per hour," paraphrasing Rutger Hauer in the mythical and unforgettable final scene of Blade Runner before the attentive gaze of Harrison Ford (back in 1982).
But that’s exactly what the NASA/ESA Hubble Space Telescope has picked up. For nearly 30 years, this telescope has helped scientists explore the universe, from observations of Jupiter’s "Great Red Spot" to data collection on galactic collisions. Now, it presents us with one of the most striking events we’ve ever seen: cosmic tsunamis capable of wiping out galaxies.
Using Hubble’s ultraviolet observations, astronomers have been able to examine exceptionally colossal energy emissions of up to 13 quasars.
What is a quasar?
Quasars are the ultra-bright nuclei of active galaxies. These objects are among the most distant and luminous objects known and their central engines are supermassive black holes filled with dust, gas and stars. As the active black hole attracts surrounding matter, it heats the gas around it to temperatures so extreme that it can make it shine one thousand times brighter than its host galaxy. That is, the quasar is created when a black hole devours matter, emitting tremendously intense radiation.
Now, thanks to Hubble, NASA has been able to observe these quasar winds that devastate interstellar space in a similar way to tsunamis here on Earth, wreaking havoc on the galaxies in which quasars reside. They are the most energetic emissions ever seen in the universe, even greater than gamma-ray explosions.
Tsunamis in Space
"No other phenomenon carries more mechanical energy," explains Nahum Arav, of Virginia Tech in Blacksburg, Virginia and lead researcher. "The amount of mechanical energy carried by these emissions is up to several hundred times greater than the entire galaxy’s luminosity of the Milky Way". In fact, driven by the fabulous pressure of the black hole, the explosions push matter away from the centre of the galaxy in the form of large jets that spring from its poles and accelerate to significant fractions of the speed of light".
According to experts, radiation pushes gas and dust far beyond what scientists previously thought, creating an event across the galaxy. As it developed, its temperature would rise to billions of degrees and matter would glow heavily in X-rays, but also throughout the spectrum of light. It is clear that anyone who witnessed this event would contemplate a fantastic show of cosmic fireworks.
A sample of such power through lanes of gas and dust in their host galaxies would cause the complete paralysis of new star formation, which could help explain cosmological riddles, as to why we find so few large galaxies in the universe and why there is a relationship between the mass of the galaxy and the mass of its central black hole.
The discovery was made possible by Hubble’s data of spectral "fingerprint" light that the gas left in its path. The instrument on board the spectrograph measures the chemical signatures of the gas molecules, and since the quasar wind accelerates the molecules, there is a Doppler effect on the observations. That shift allows them to estimate the speed of these cosmic tsunamis. As if this were not enough, they also discovered another emission flow accelerating faster than any other: it increased from nearly 69 million km/h to approximately 74 million km/h over a three-year period. Researchers believe that its acceleration will continue to increase as time passes.
What new surprises will Hubble bring us?
Reference: Los hallazgos se publicaron en una serie de seis artículos en Astrophysical Journal Supplements:
Nahum Arav et al. 2020. HST/COS Observations of Quasar Outflows in the 500–1050 Å Rest Frame. I. The Most Energetic Outflows in the Universe and Other Discoveries. ApJS 247, 37; doi: 10.3847/1538-4365/ab66af
Xinfeng Xu et al. 2020. HST/COS Observations of Quasar Outflows in the 500–1050 Å Rest Frame. II. The Most Energetic Quasar Outflow Measured to Date. ApJS 247, 38; doi: 10.3847/1538-4365/ab596a
Timothy R. Miller et al. 2020. HST/COS Observations of Quasar Outflows in the 500–1050 Å Rest Frame. III. Four Similar Outflows in 2MASS J1051+1247 with Enough Energy to Be Major Contributors to AGN Feedback. ApJS 247, 39; doi: 10.3847/1538-4365/ab5967
Xinfeng Xu et al. 2020. 2020 HST/COS Observations of Quasar Outflows in the 500–1050 Å Rest Frame. IV. The Largest Broad Absorption Line Acceleration. ApJS 247, 40; doi: 10.3847/1538-4365/ab4bcb
Timothy R. Miller et al. 2020. HST/COS Observations of Quasar Outflows in the 500–1050 Å Rest Frame. V. Richness of Physical Diagnostics and Ionization Potential-dependent Velocity Shift in PKS J0352-0711. ApJS 247, 41; doi: 10.3847/1538-4365/ab5969
Xinfeng Xu et al. 2020. HST/COS Observations of Quasar Outflows in the 500–1050 Å Rest Frame. VI. Wide, Energetic Outflows in SDSS J0755+2306. ApJS 247, 42; doi: 10.3847/1538-4365/ab5f68