Dusty filaments in NGC 4696
Wide-field image of NGC 4696 (ground-based image)
Videos
Zoom in on NGC 4696
Pan across NGC 4696
New observations from the NASA/ESA Hubble
Space Telescope have revealed the intricate structure of the galaxy NGC
4696 in greater detail than ever before. The elliptical galaxy is a
beautiful cosmic oddity with a bright core wrapped in system of dark,
swirling, thread-like filaments.
NGC 4696 is a member of the Centaurus galaxy cluster,
a swarm of hundreds of galaxies all sitting together, bound together by
gravity, about 150 million light-years from Earth and located in the constellation of Centaurus.
Despite the cluster’s size, NGC 4696 still manages to stand out from
its companions — it is the cluster’s brightest member, known for obvious
reasons as the Brightest Cluster Galaxy . This puts it in the same category as some of the biggest and brightest galaxies known in the Universe.
Even if NGC 4696 keeps impressive company, it has a further
distinction: the galaxy’s unique structure. Previous observations have
revealed curling filaments that stretch out from its main body and carve
out a cosmic question mark in the sky (heic1013), the dark tendrils encircling a brightly glowing centre.
An international team of scientists, led by astronomers from the
University of Cambridge, UK, have now used new observations from the
NASA/ESA Hubble Space Telescope to explore this thread-like structure in
more detail. They found that each of the dusty filaments has a width of
about 200 light-years, and a density some 10 times greater than the
surrounding gas. These filaments knit together and spiral inwards
towards the centre of NGC 4696, connecting the galaxy’s constituent gas
to its core.
In fact, it seems that the galaxy’s core is actually responsible for
the shape and positioning of the filaments themselves. At the centre of
NGC 4696 lurks an active supermassive black hole. This floods the
galaxy’s inner regions with energy, heating the gas there and sending
streams of heated material outwards.
It appears that these hot streams of gas bubble outwards, dragging
the filamentary material with them as they go. The galaxy’s magnetic
field is also swept out with this bubbling motion, constraining and
sculpting the material within the filaments.
At the very centre of the galaxy, the filaments loop and curl inwards in an intriguing spiral shape, swirling around the supermassive black hole at such a distance that they are dragged into and eventually consumed by the black hole itself.
Understanding more about filamentary galaxies such as NGC 4696 may
help us to better understand why so many massive galaxies near to us in
the Universe appear to be dead; rather than forming newborn stars from
their vast reserves of gas and dust, they instead sit quietly, and are
mostly populated with old and aging stars. This is the case with NGC
4696. It may be that the magnetic structure flowing throughout the
galaxy stops the gas from creating new stars.
More Information
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
Image credit: NASA, ESA, Andy Fabian
Links
Contacts
Andy Fabian
University of Cambridge
Cambridge, United Kingdom
Tel: +44 1223 337509
Email: acf@ast.cam.ac.uk
Mathias Jäger
ESA/Hubble, Public Information Officer
Garching bei München, Germany
Tel: +49 176 62397500
Email: mjaeger@partner.eso.org
Source: ESO/Hubble/News
