Can a black hole fire up the cold heart of the Phoenix Galaxy Cluster?


Date:
August 31, 2020
Source:
National Institutes of Natural Sciences
Summary:
Radio astronomers have detected jets of hot gas blasted out by
a black hole in the galaxy at the heart of the Phoenix Galaxy
Cluster, located 5.9 billion light-years away in the constellation
Phoenix. This is an important result for understanding the
coevolution of galaxies, gas, and black holes in galaxy clusters.



FULL STORY ========================================================================== Radio astronomers have detected jets of hot gas blasted out by a black
hole in the galaxy at the heart of the Phoenix Galaxy Cluster, located
5.9 billion light-years away in the constellation Phoenix. This is an
important result for understanding the coevolution of galaxies, gas,
and black holes in galaxy clusters.


========================================================================== Galaxies are not distributed randomly in space. Through mutual
gravitational attraction, galaxies gather together to form collections
known as clusters. The space between galaxies is not entirely empty. There
is very dilute gas throughout a cluster which can be detected by X-ray observations.

If this intra-cluster gas cooled, it would condense under its own gravity
to form stars at the center of the cluster. However, cooled gas and stars
are not usually observed in the hearts of nearby clusters, indicating
that some mechanism must be heating the intra-cluster gas and preventing
star formation.

One potential candidate for the heat source is jets of high-speed gas accelerated by a super-massive black hole in the central galaxy.

The Phoenix Cluster is unusual in that it does show signs of dense cooled
gas and massive star formation around the central galaxy. This raises
the question, "does the central galaxy have black hole jets as well?"
A team led by Takaya Akahori at the National Astronomical Observatory
of Japan used the Australia Telescope Compact Array (ATCA) to search for
black hole jets in the Phoenix Galaxy Cluster with the highest resolution
to date. They detected matching structures extending out from opposite
sides of the central galaxy. Comparing with observations of the region
taken from the Chandra X-ray Observatory archive data shows that the
structures detected by ATCA correspond to cavities of less dense gas, indicating that they are a pair of bipolar jets emitted by a black
hole in the galaxy. Therefore, the team discovered the first example,
in which intra-cluster gas cooling and black hole jets coexist, in the
distant Universe.

Further details of the galaxy and jets could be elucidated through higher- resolution observations with next generation observational facilities,
such as the Square Kilometre Array scheduled to start observations in
the late 2020s.


========================================================================== Story Source: Materials provided by
National_Institutes_of_Natural_Sciences. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Takuya Akahori, Tetsu Kitayama, Shutaro Ueda, Takuma Izumi,
Kianhong Lee,
Ryohei Kawabe, Kotaro Kohno, Masamune Oguri, Motokazu
Takizawa. Discovery of radio jets in the Phoenix galaxy cluster
center. Publications of the Astronomical Society of Japan, 2020;
72 (4) DOI: 10.1093/pasj/psaa039 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200831094732.htm

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