Half of the gaseous hydrogen in the universe, for a long time, has been found

Astronomers total all normal materials – stars, galaxies and gas – in the universe today have been embarrassing the total material produced in Big Bang 13.6 billion years ago. In fact, more than half of the normal material – half of the 15% of the material of the universe which is not dark matter – cannot be taken into account in the bright stars and gaseous that we see.

New measures, however, seem to have found this missing material in the form of very diffuse and invisible ionized gas hydrogen, which forms a halo around the galaxies and is more swollen and extended than what astronomers thought it.

The results not only relieve a conflict between astronomical observations and the best proven model of the evolution of the universe from the big bang, they also suggest that the massive black holes in the centers of the galaxies are more active than we thought before, the gas of the fountain much more distant from the galactic center than expected – out of five times more distant, the team found.

“We think that once we get away from the galaxy, we recover all the missing gases,” said Boryana Hadzhiyska, a postdoctoral scholarship Miller at the University of California in Berkeley, and the first author of a newspaper reporting the conclusions. “To be more precise, we have to do a careful analysis with simulations, which we have not done. We want to do a careful job.”

“The measures are certainly in line with the search for all gas,” said her colleague, Simone Ferraro, the main scientist at Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley who saw clues of this vast ionized hydrogen halo in the analyzes published three years ago.

The results of the study, co-written by 75 scientists of world institutions arxiv and undergo the peer review in the newspaper Physical examination letters. Hadzhiyska and Ferraro are researchers from the Berkeley Center for Cosmological Physics in the ICH Berkeley Physics department, as well as at Berkeley Lab.

Stacked galaxies

Although the still mysterious dark matter constitutes the majority – around 84% – in the universe, the rest is a normal material. Only about 7% of normal material is in the form of stars, while the rest is in the form of invisible hydrogen – most ionized – in galaxies and filaments that connect galaxies in a sort of cosmic network.

The ionized gas and the associated electrons expressed in this network of filaments are called the hot hot intergalactic environment, which is too cold and too diffuse to be seen with the usual techniques to eliminate astronomers, and has therefore remained elusive so far.

In the new article, the researchers estimated the distribution of ionized hydrogen around galaxies by stacking images of around 7 million galaxies, which is in about 8 billion light years of the earth-and measuring the slight gradation or clarification of the cosmic microwave background caused by a diffusion of the radiation by the electrons in the ionized effect.

“The cosmic microwave bottom is at the back of everything we see in the universe. It is the edge of the observable universe,” said Ferraro. “So you can use it as a backlight to see where the gas is.”

The images of the galaxy used – all the light red galaxies – were collected by the Spectroscopic black energy (Desi) instrument on the 4 -meter Mayall telescope at the National Observatory of Kitt Peak in Tucson, Arizona. The instrument, built by a collaboration whose headquarters are in Berkeley Lab, is investigating tens of millions of galaxies and quasars to build a 3D card covering the universe at 11 billion light years from the earth in order to measure the effect of dark energy on the extension of the universe.

Cosmic microwave (CMB) background measurements around these galaxies were carried out by the Atacama cosmology telescope (ACT) in Chile, which made the most precise measurements to date of the CMB before its discovery in 2022.

The analysis was carried out in collaboration with Bernardita Ried Guachalla, a graduate student at the University of Stanford; Emmanuel Schaan, Slac national scientist Accelerator Laboratory at Menlo Park; and the desi and acts teams.

Galactic feedback

Astronomers have generally thought that massive black holes in galaxies centers expel gas into material jets only during their years of formation, when the central black hole engulfs gas and stars and produces a lot of radiation. This distinguishes them as what astronomers call active galactic nuclei (AGN) or Quasars.

If, as the new study suggests, the ionized hydrogen halo around the galaxies is more diffuse, but also more extensive than what thinks, that implies that central black holes can active to become active at other times of their lives.

“A problem that we do not understand concerns the AGNs, and one of the hypotheses is that they light up and go out from time to time in what is called a service cycle,” said Hadzhiyska.

Astronomers refer to the expulsion of gas and its subsequent discount in the galactic disc as a feedback which regulates the formation of new stars throughout the galaxy. Ferraro, Schaan and their colleagues reported more extensive comment councils in previous work in 2020, when Schaan was a postdoctoral scholarship holder at Berkeley Lab.

But the new work incorporates more galaxies and produces a more precise measurement. The subsequent work of Ried Guachalla confirmed the results with the spectroscopic sample desi and were able to study the gas in closer galaxies, stressing that the gas is not distributed uniformly around them, but follows “cosmic filaments” which permeate the universe.

Hadzhiyska noted that the current simulations of the evolution of the galaxy will have to incorporate this more vigorous feedback into their models. Some new models are already doing so to produce stronger simulations in better agreement with new data.

The identification of the missing material, or of the bars, in the universe, also has implications for other aspects of cosmic evolution.

“Knowing where gas has become one of the most serious limiting factors to try to withdraw cosmology from current and future surveys. We have somehow hit this wall, and that’s the right time to answer these questions,” said Ferraro. “Once you know where the gas is, you can ask:” What is the consequence for cosmological problems? “”

On the one hand, the expulsion of the gas from the nuclei of these massive galaxies calls into question the hypothesis that gas follows dark matter, said Hadzhiyska. Substitute of this gas expulsion can introduce inconsistencies in cosmological models, while new results can really solve certain problems on the cluster of the universe.

“There are a large number of people interested in using our measures to carry out a very in-depth analysis that includes this gas,” she said. “The people of astronomy care about it to understand the training and the evolution of galaxies.”

The technique used by the team, the Sunyaev-Zel’Dovich kinematic effect could also be used to probe the start of the universe, said Hadzhiyska. This could give an overview of the large -scale structure of the universe and the laws of physics in the early universe and allow scientists to test gravity and general relativity.