Hubble’s ultraviolet observations allowed astronomers to witness the most energetic outflows ever in the universe. The outflows were emitted by quasars and tear across interstellar space like tsunamis, wreaking havoc on the galaxies in which the quasars live.
As this cosmic tsunami slams into interstellar material, the temperature at the shock front spikes to billions of degrees, where material glows largely in X-rays but also widely across the light spectrum. Anyone witnessing this event would see a brilliant celestial display.
Mathematical simulations of galaxy evolution propose that such outflows can clarify some significant cosmological riddles, for example, why astronomers notice scarcely any large galaxies and why there is a connection between the mass of the galaxy and the mass of its central black hole. This investigation shows that such powerful quasar outflows should be predominant in the early universe.
Astronomers studied 13 quasar outflows. They were able to clock the breakneck speed of gas being accelerated by the quasar wind by looking at spectral “fingerprints” of light from the glowing gas.
The data show that these light absorption features created from material along the path of the light were shifted in the spectrum because of the gas’s fast motion across space. This is due to the Doppler effect, where an object’s motion compresses or stretches wavelengths of light depending on whether it is approaching or receding from us. Only Hubble has a specific range of ultraviolet sensitivity that allows astronomers to obtain the necessary observations leading to this discovery.
Besides measuring the most energetic quasars ever observed, the team also discovered another outflow accelerating faster than any other. It increased from nearly 43 million miles per hour to roughly 46 million miles per hour in three years.
Gerard Kriss of the Space Telescope Science Institute in Baltimore, Maryland, said, “Hubble’s ultraviolet observations allow us to follow the whole range of energy output from quasars, from cooler gas to the extremely hot, highly ionized gas in the more massive winds. These were previously only visible with much more difficult X-ray observations. Such powerful outflows may yield new insights into the link between the growth of a central supermassive black hole and the development of its entire host galaxy.”
The findings were published in a series of six papers in March 2020, a focus issue of The Astrophysical Journal Supplements.