UC Berkeley student disproves discovery of gigantic black hole

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UC Berkeley astrophysics graduate student Kareem El-Badry disproved a discovery by Chinese researchers of a gigantic black hole Dec. 9.

El-Badry said he was skeptical when he first read the original study three weeks ago, which claimed the discovery of a black hole 70 times the size of the sun. The claim would have been extraordinary if it were true, according to El-Badry, as the type of black hole discovered is usually expected to be less than half that size which would have potentially shed doubt on the established theoretical model of how a star evolves. El-Badry added that this is why people in the field, including him, were very intrigued by the paper.

El-Badry said his suspicion arose from his familiarity with data from stars, which he works with in his research. Analyzing the same data used in the study, El-Badry found something researchers did not correct.

“They claimed to get the spectrum of the star and saw it accelerating towards us, then moving away,” El-Badry said. “But I found that the emission line was not moving at all … meaning that it’s not coming from the black hole but from something in a larger scale … not from a smaller disk just around the black hole.”

After correcting the systematic defect, he found the mass of the black hole was more likely five to 10 solar masses, which El-Badry said is to be expected.

“In today’s dose of cold water, we argue that the data was misinterpreted,” El-Badry tweeted Dec. 9 after he published his paper. “There is no evidence of an unusually massive (black hole).”

Although two other research groups posted papers the same day rebutting the findings, only El-Badry’s paper used the original researchers’ data to dispute the claims.

El-Badry said he still believes this area of research is worthy of discussion to find and comprehend the 10 million to 100 million large black holes suspected to exist in the Milky Way.

“In recent years, there have been a lot of investments in this research,” El-Badry said. “But what is up there is still uncharted.”

Contact Angelina Wang at [email protected] and follow her on Twitter at @dc_angelina.