According to a recent research, the strange stream of stars flowing across
space may not be caused by a renegade black hole.
Astronomers are perplexed by a mystery starburst that appears to be flowing
through space like a giant cosmic river. Is it a "renegade" black hole
tearing across space, or is it actually a strangely flat galaxy? The latter
is supported by recent studies, although the riddle is far from being
solved.
It is believed that the cosmic streak, which was first spotted by NASA's
Hubble Space Telescope, measures 200,000 light-years in length, or roughly
twice the Milky Way's diameter. The streak may have been caused by a runaway
supermassive black hole slicing through a cloud of star gas and dust around
7.5 billion light-years from Earth, according to a study published in
The Astrophysical Journal
Letters last month.
The scientists hypothesized that the object's gravity and velocity would
have ignited the gas and left a path of blazing stars in its wake. A rogue
supermassive black hole is an entity that is supposed to roam the universe
after being evicted from its host galaxy, maybe as a result of collisions
with other black holes. This thrilling finding would represent the first
sighting of one.
The strangely thin streak may simply be a flat galaxy seen from its edge,
much like the rim of a plate, according to the new study, which was
published in the journal
Astronomy & Astrophysics. The Milky Way has a bulge of stars in its core, but this hypothetical
galaxy, which is known as a thin or flat galaxy, would be completely
flat.
The authors of the study compared the in issue stars to a well-known flat
galaxy dubbed IC5249, situated around 100 million light-years from Earth, to
corroborate their interpretation. They discovered that the stars' masses and
velocities in the two objects agreed.
They are "extraordinarily similar," said
Mireia Montes, a co-author of the new study and an astronomer at the Canary Islands
Institute of Astrophysics (IAC),
in a release.
Even the researchers of the study are slightly dismayed by this
result.
Jorge Sánchez Almeida, an astronomer at the IAC and the study's primary author, said in a
statement, "In some ways, it is also unfortunate." He said that it would
have been thrilling for the scientific world to see the first black hole to
vanish.
The 'runaway' black hole may be saved
The primary author of the original runaway black hole article and Yale
University professor of physics and astronomy
Pieter van Dokkum is not persuaded by the new explanation. Van Dokkum pointed out
various aspects of the streak findings that contradict the galaxy concept in
a response article that was published on April 29 to the preprint service
arXiv.org.
One thing that supports the idea that the streak was produced by a
fast-moving object, such as a supermassive black hole, being ejected from
the compact galaxy's center, he wrote, is that observations of the streak in
far-ultraviolet wavelengths show that the stellar stream is directly
connected to a nearby compact galaxy. There should be a distinct heat
signature where the two galaxies converge if the streak was really a flat
galaxy.
The leading edge of the runaway black hole would be just where observations
also reveal a stunningly bright "knot" of ionized gas, according to van
Dokkum. This lends even more credence to the black hole idea, which is not
taken into consideration by the edge-on galaxy theory.
The IAC team acknowledged in the statement that the streak is also
exceptionally big for a galaxy that is so far away from Earth.
Van Dokkum wrote in an email to Live Science, "We can very nearly rule out
an edge-on galaxy, while there may be alternative reasons for the
streak.
Whatever the answer, it is important to keep researching this unique
celestial river. This summer's next Hubble observations of the streak
"should be definitive" in terms of supporting or refuting the galaxy
concept, according to van Dokkum. He continued by saying that the enigmatic
stripe has also been chosen for upcoming studies by the powerful James Webb
Space Telescope, which would search for clear signs of black holes
nearby.
