Artistic conception of the James Webb space telescope. Credit: NASA GSFC / CIL / Adriana Manrique Gutiérrez
The Webb Space Telescope team continues to work to put the scientific instruments into service, the final step before starting scientific operations in the summer. We recently saw the spectacular image of the black hole in the center of our Milky Way galaxy, captured by the Event Horizon telescope. One of the enigmas of modern astronomy is how each large galaxy came to have a huge central black hole, and how some of these black holes are surprisingly large even in very early times in the universe. We asked Roberto Maiolino, a member of Webb’s Near-Infrared Spectrometer (NIRSpec) instruments scientific team, to explain how Webb will help us answer some of these questions.
“One of the most exciting areas of discovery that Webb is about to open is the search for primitive black holes in the early universe. These are the seeds of the much more massive black holes that astronomers have found in galactic nuclei. Most galaxies (probably all) have black holes at their center, with masses ranging from millions to billions of times the mass of our Sun. These supermassive black holes have become so large that they thicken matter in around as well as through the fusion of smaller black holes.
“An intriguing recent finding has been the discovery of hypermassive black holes, with masses of several billion solar masses, already existing when the universe was only about 700 million years old, a small fraction of its current age of 13,800. This is a disconcerting result, as in such early times there is not enough time for such hypermassive black holes to grow, according to standard theories.Some scenarios have been proposed to solve this riddle.
“One possibility is that the black holes, resulting from the death of the first generation of stars in the early universe, have accumulated material at an exceptionally high rate. Another scenario is that primitive, virgin gas clouds have not yet enriched with chemical elements heavier than helium, they could collapse directly to form a black hole with a mass of a few hundred thousand solar masses and then accumulate matter to evolve into the hyper- black holes observed in later epochs Finally, dense nuclear star clusters in the center of baby galaxies may have produced intermediate-mass black hole seeds, by stellar collisions or melting of black star-shaped holes. And then become much more massive by accretion.
This illustration shows the known black hole populations (large black dots) and the candidate progenitors of the black hole in the early universe (shaded regions). Credit: Roberto Maiolino, University of Cambridge
Webb is about to open up a whole new space of discovery in this area. It is possible that the first black hole seeds originally formed in the “baby universe” just a few million years after the big Webb is the perfect “time machine” for knowing these primordial objects, and its exceptional sensitivity makes Webb able to detect extremely distant galaxies, and because of the time it takes for light from galaxies to travel to us, we will see them as they were in the distant past.
Webb’s NIRSpec instrument is especially suitable for identifying primitive black hole seeds. My colleagues in the NIRSpec instrument science team and I will look for their signatures during the “active” phases when they are devouring with voracious and rapidly growing In these phases, the surrounding material becomes extremely hot and bright and ionizes the atoms around them and the host galaxies.
“NIRSpec will scatter light from these systems into spectra or ‘rainbows.’ will measure the velocity of the gas orbiting around these primitive black holes.Smaller black holes will be characterized by lower orbital velocities.Black hole seeds formed in virgin clouds will be identified by the absence of features associated with any heavier element than helium.
“I look forward to using Webb’s unprecedented ability to find these progenitors of the black hole, with the ultimate goal of understanding their nature and origin. The early universe and the seed kingdom of the black hole is a completely unexplored territory. that my colleagues and I are very excited to explore with Webb. “
– Roberto Maiolino, Professor of Experimental Astrophysics and Director of the Kavli Institute of Cosmology, University of Cambridge
Written by:
- Jonathan Gardner, Senior Assistant Scientist for the Webb Project, NASA’s Goddard Space Flight Center
- Stefanie Milam, Assistant Scientist for the Webb Project for Planetary Sciences, NASA’s Goddard Space Flight Center