Credit: Dr Ananda Hota, GMRT, CFHT, MeerKAT. Licence type: Attribution (CC BY 4.0)
With the help of citizen scientists, a
team of astronomers has discovered a unique black hole spewing a fiery
jet at another galaxy. The black hole is hosted by a galaxy around one
billion light years away from Earth named RAD12. The work was published
today in Monthly Notices of the Royal Astronomical Society (Letters).
Galaxies
are typically divided into two major classes based on their morphology:
spirals and ellipticals. Spirals have optically-blue looking spiral
arms with an abundance of cold gas and dust. In spiral galaxies, new
stars form at an average rate of one Sun-like star per year. In contrast
elliptical galaxies appear yellowish and lack distinct features such as
spiral arms.
Star
formation in elliptical galaxies is very scarce; it is still a mystery
to astronomers as to why the elliptical galaxies we see today have not
been forming new stars for billions of years. Evidence suggests that
supermassive or ‘monster’ black holes are responsible. These ‘monster’
black holes spew gigantic jets made of electrons moving at very high
speeds at other galaxies, depleting the fuel required for future star
formation: cold gas and dust.
The
unique nature of RAD12 had been observed in 2013 using optical data
from the Sloan Digitised Sky Survey (SDSS) and radio data from the Very
Large Array (FIRST survey). However, follow-up observation with the
Giant Meterwave Radio Telescope (GMRT) in India was required to confirm
its truly exotic nature: The black hole in RAD12 appears to be ejecting
the jet only towards a neighbouring galaxy, named RAD12-B. In all cases,
jets are ejected in pairs, moving in opposite directions at
relativistic speeds. Why only one jet is seen coming from RAD12 remains a
puzzle to astronomers.
A
conical stem of young plasma is seen being ejected from the centre and
reaches far beyond the visible stars of RAD12. The GMRT observations
revealed that the fainter and older plasma extends far beyond the
central conical stem and flares out like the cap of a mushroom (seen in
red in the tricolour image). The whole structure is 440 thousand light
years long, which is much larger than the host galaxy itself.
RAD12
is unlike anything known so far; this is the first time a jet has been
observed to collide with a large galaxy like RAD12-B. Astronomers are
now one step closer to understanding the impact of such interactions on
elliptical galaxies, which may leave them with little cold gas for
future star formation.
Research lead Dr Ananda Hota says, "We are excited to have spotted a rare system that helps us understand radio jet feedback of supermassive black holes on star formation of galaxies during mergers. Observations with the GMRT and data from various other telescopes such as the MeerKAT radio telescope strongly suggest that the radio jet in RAD12 is colliding with the companion galaxy. An equally important aspect of this research is the demonstration of public participation in making discoveries through the RAD@home Citizen Science research collaboratory."
Source: Royal Astronomical Society (RAS)
Contacts:
Gurjeet Kahlon
Royal Astronomical Society
Mob: +44 (0)7802 877 700
press@ras.ac.uk
Dr Robert Massey
Royal Astronomical Society
Mob: +44 (0)7802 877699
press@ras.ac.uk
Science Contacts
Dr Ananda Hota
UM-DAE Centre for Excellence in Basic Sciences
RAD@home Astronomy Collaboratory
University of Mumbai hotaananda@gmail.com
Dr Pratik Dabhade
Observatoire de Paris (College de France)
pratikdabhade13@gmail.com
Dr Sravani Vaddi
Arecibo Observatory
sravani.vaddi@gmail.com
Ms Megha Rajoria
RAD@home Astronomy Collaboratory
megharajoria3@gmail.com
Futher Information
The RAD@home Collaboratory
welcomes collaboration with other astronomers for future investigation
in multiple wavelength campaigns with multiple telescopes. The
Collaboratory invites not only professional astronomers but also
interested citizens with university-level science degrees to participate
in this citizen Science research program. RAD12 Discovery is a
beautiful example of how the public (particularly University science
students) can directly participate in real astronomy discovery sitting
at home.
Other than Dr Hota, Dr Dabhade and Dr Vaddi, the team includes astronomers Dr
Chiranjib Konar (Amity University), Dr Sabyasachi Pal (Midnapore City
College), Dr Mamta Gulati (Thapar Institute of Engineering and
Technology), Dr C S. Stalin (Indian Institute of Astrophysics) and Mr Ck
Avinash, Mr Avinash Kumar, Ms Megha Rajoria, Ms Arundhati Purohit from RAD@home Collaboratory.
The research appears in ‘RAD@home citizen science discovery of an AGN spewing a large unipolar radio bubble onto its merging companion galaxy’, Ananda Hota et al.,published in Monthly Notices of the Royal Astronomical Society, in press.
Animation: https://www.youtube.com/watch?v=BwnfUq5mCEE
Caption: Animation of an AGN (Active Galactic Nucleus) spewing a large unipolar radio bubble on to its merging companion galaxy.
Credit: Dr Ananda Hota, Dr Pratik Dabhade, Dr Sravani Vaddi
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