January 27, 2023

Astronomers dig out buried black holes with NASA’s Chandra

This result assists give astronomers a more precise census of black openings in the universe

Hundreds of black holes previously hidden, or buried, are already found using NASA’s Chandra X-ray Observatory.

This result helps give astronomers a far more accurate census of dark holes in the universe.

The  black holes   in this new study are the supermassive variety that contain millions or perhaps billions of times the bulk of the sun. While astronomers think that almost all large galaxies harbor giant black holes in their centers, only some of the black holes will be actively pulling in material that produces radiation, and some will be buried underneath dust and gasoline.

By merging data from the Chandra Source Catalog— a public repository including hundreds of thousands of Xray sources detected by the observatory over its first fifteen years— and  optical data   through the Sloan Digital Sky Study (SDSS), a team associated with astronomers was able to identify numerous black holes that experienced previously been hidden. They are in galaxies not formerly identified to contain quasars, extremely bright objects along with rapidly growing supermassive black holes.

“ Astronomers have already identified huge numbers of black holes, but many stay elusive, ” said Dong-Woo Kim of the Center just for Astrophysics | Harvard & Smithsonian (CfA), who brought the study. “ Our research has uncovered a missing population and helped us know how they are behaving. ”

For about 40 years scientists have known about galaxies that look normal within optical light— with light from stars and fuel but not the distinctive optical signatures of a quasar— but shine brightly in X-rays. They refer to these items as “ X-ray-bright, optically normal galaxies, ” or “ XBONGs. ”

By systematically combing through the deep Chandra Resource Catalog and comparing in order to SDSS optical data, the particular researchers identified 817 XBONG candidates, more than ten moments the number known before Chandra was in operation. Chandra’s sharp images, matching the quality of those people from SDSS, and the large amount of data in the Chandra Resource Catalog made it possible to detect this many XBONG candidates. Further study exposed that about half of these XBONGs represent a population associated with previously hidden black holes.

“ These types of results show how effective it is to compare X-ray and optical data mines, ” said co-author Amanda Malnati, an  undergraduate pupil   at Smith College in Northampton, Ma. “ The Chandra Resource Catalog is a growing value that will help astronomers make discoveries for years to come. ”

X-rays are particularly useful to search for rapidly growing dark holes because material whirling around them is superheated to millions of degrees and glows strongly in Xray wavelengths. A thick cocoon of gas and dust surrounding a black gap will block most or all the light at optic wavelengths. X-rays, however , go through the cocoon much more effortlessly to be detected by Chandra.

After learning the amount of X-rays detected from different energies for each supply, the team concluded that about half the XBONG candidates include X-ray sources that are buried under thick gas mainly because relatively small amounts of low-energy X-rays were detected. Such X-rays are blocked easier by layers of encircling gas than higher-energy types.

These Xray sources are so bright that almost all of them must be from material surrounding rapidly growing supermassive black holes. Data through NASA’s Wide-Field Infrared Survey Explorer provided additional proof that about half of the XBONGs are buried, growing supermassive black holes. These black holes range in distances between 550 million and 7. 8 billion light-years from Earth.

“ It’s not every day that you can say you discovered a black hole, ” said co-author Alyssa Cassity, a graduate student at the University or college of British Columbia. “ So , it’s very exciting to understand that we have discovered hundreds of all of them. ”

The true reason for the XBONGs that are not buried underneath thick fuel is less clear. Regarding 100 of the X-ray resources may not be single points associated with X-rays, but instead appear spread out. Some of these may be galaxies within previously unidentified groups or even clusters of galaxies, that are known to contain large amounts of hot, X-ray giving out gas. No more than about twenty percent of the XBONGs can be grouped this way. The remaining 30% may contain some supermassive black holes located in galaxies in which the optical signals from the  supermassive black openings   are diluted by relatively bright light from stars. Scientists will need extra research to sort out the true character of these XBONGs.

Dong-Woo Kim presented these results at the  241st meeting of the American Astronomical Society   in Seattle.

Leave a Reply

Your email address will not be published. Required fields are marked *