First Truly Isolated Black Hole Discovered In The Cosmos

For the first time, a solitary black hole drifting through the cosmos has been confirmed. After much excitement, a closer examination has unveiled the true nature of this mysterious object.

The latest analysis reveals that the black hole has a mass approximately 7.15 times that of the Sun, is located about 4,958 light-years away, and is traveling through space at a speed of roughly 51 kilometers (32 miles) per second.

What makes this black holes truly unique is that it’s the only confirmed solitary black hole drifting through the Universe. Researchers typically find black holes of this type with companions, often stars in our galaxy. It’s the subtle wobbles in these more visible stars that reveal the presence of the black hole.

At greater distances, scientists have detected pairs of black holes by the gravitational waves they produce as they orbit each other and eventually merge

Without a companion, this black hole revealed itself through a different process known as gravitational microlensing. Its strong gravity distorted the light from a distant star, magnifying it and briefly altering its apparent position in the sky.

The estimated mass of the lens, along with the absence of any emitted light, points to it being a black hole. However, the process of identifying it wasn’t as straightforward as it may seem.

Initial Detection in 2011: Data from OGLE and MOA Surveys Reveal Rare Event

The object was first detected in 2011 through data from two independent surveys specifically searching for this type of event: the Optical Gravitational Lensing Experiment (OGLE) and Microlensing Observations in Astrophysics (MOA).

The Hubble Space Telescope conducted eight follow-up observations over six years to measure the extent of the distortion in the starlight. Sixteen different telescopes gathered photometric data, and researchers made spectroscopy observations at the point of maximum amplification.

Altogether, this data suggested the presence of a solitary black hole with a mass of approximately 7.1 times that of the Sun, located around 5,153 light-years away.

However, a second analysis in 2022, which utilized additional Hubble data, reached a different conclusion. This team revised the mass estimate to a range between 1.6 and 4.4 solar masses. Since this is typically too low for a black hole, they suggested that a neutron star might be a more probable candidate.

Nevertheless, a series of follow-up studies, including one from the neutron star team, have provided stronger support for the black hole theory.

New Analysis Confirms Identity: Extended Hubble and OGLE Data

A new analysis, which involves several scientists from the original study, clearly verifies that identity. It incorporates three additional Hubble observations, extending the period to 11 years, along with updated OGLE data.

In a new paper, the team writes, “By incorporating the additional Hubble observations and updated photometry into our revised analysis, we achieve more accurate results that are still in line with our previous measurements and reaffirm our conclusion that the lens is a stellar-mass black hole.”

A major challenge in observing the lens is that the nearby star outshines the light from the background star To overcome this, the scientists had to meticulously subtract the extra light in each observation and also adjust for the changes caused by varying thermal conditions during each Hubble orbit.

The team also looked for any signs of a companion and discovered that there is no object larger than 0.2 solar masses within a distance of at least 2,000 times the Earth-Sun distance.

While this might be the first confirmed solo black hole, it’s certainly not the only one. The universe likely teems with these unseen outlaws, though it’s incredibly rare for one to make itself known to us.

Read the original article one: Science Alert

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