A spiral within a spiral

Esahubble_potw1221a_1024

esahubble_potw1221a May 21st, 2012

Credit: ESA/Hubble & NASA

The NASA/ESA Hubble Space Telescope captured this image of the spiral galaxy known as ESO 498-G5. One interesting feature of this galaxy is that its spiral arms wind all the way into the centre, so that ESO 498-G5's core looks like a bit like a miniature spiral galaxy. This sort of structure is in contrast to the elliptical star-filled centres (or bulges) of many other spiral galaxies, which instead appear as glowing masses, as in the case of NGC 6384. Astronomers refer to the distinctive spiral-like bulge of galaxies such as ESO 498-G5 as disc-type bulges, or pseudobulges, while bright elliptical centres are called classical bulges. Observations from the Hubble Space Telescope, which does not have to contend with the distorting effects of Earth's atmosphere, have helped to reveal that these two different types of galactic centres exist. These observations have also shown that star formation is still going on in disc-type bulges and has ceased in classical bulges. This means that galaxies can be a bit like Russian matryoshka dolls: classical bulges look much like a miniature version of an elliptical galaxy, embedded in the centre of a spiral, while disc-type bulges look like a second, smaller spiral galaxy located at the heart of the first a spiral within a spiral. The similarities between types of galaxy bulge and types of galaxy go beyond their appearance. Just like giant elliptical galaxies, the classical bulges consist of great swarms of stars moving about in random orbits. Conversely, the structure and movement of stars within disc-type bulges mirror the spiral arms arrayed in a galaxy's disc. These differences suggest different origins for the two types of bulges: while classical bulges are thought to develop through major events, such as mergers with other galaxies, disc-type bulges evolve gradually, developing their spiral pattern as stars and gas migrate to the galaxys centre. ESO 498-G5 is located around 100 million light-years away in the constellation of Pyxis (The Compass). This image is made up of exposures in visible and infrared light taken by Hubbles Advanced Camera for Surveys. The field of view is approximately 3.3 by 1.6 arcminutes.

Provider: Hubble Space Telescope | ESA

Image Source: https://www.spacetelescope.org/images/potw1221a/

Curator: ESA/Hubble, Garching bei München, Germany

Image Use Policy: Creative Commons Attribution 4.0 International License

Image Details

Image Type
Observation
Object Name
ESO 498-G5
Subject - Local Universe
Galaxy > Type > Spiral
Esahubble_potw1221a_128
 

Position Details

Position (ICRS)
RA = 9h 24m 40.9s
DEC = -25° 5’ 35.5”
Orientation
North is 89.0° CCW
Field of View
3.0 x 1.6 arcminutes
Constellation
Pyxis

Color Mapping

  Telescope Spectral Band Wavelength
Red Hubble (ACS) Infrared (I) -
Pseudocolor Hubble (ACS) Optical (B+I) -
Blue Hubble (ACS) Optical (B) -
Esahubble_potw1221a_1280
×
ID
potw1221a
Subject Category
C.5.1.1  
Subject Name
ESO 498-G5
Credits
ESA/Hubble & NASA
Release Date
2012-05-21T10:00:00
Lightyears
Redshift
Reference Url
https://www.spacetelescope.org/images/potw1221a/
Type
Observation
Image Quality
Distance Notes
from NED
Facility
Hubble Space Telescope, Hubble Space Telescope, Hubble Space Telescope
Instrument
ACS, ACS, ACS
Color Assignment
Red, Pseudocolor, Blue
Band
Infrared, Optical, Optical
Bandpass
I, B+I, B
Central Wavelength
Start Time
Integration Time
Dataset ID
Notes
Coordinate Frame
ICRS
Equinox
J2000
Reference Value
141.17033061, -25.0931809646
Reference Dimension
3666.0, 1917.0
Reference Pixel
1833.0, 958.0
Scale
-1.38492868596e-05, 1.38492868596e-05
Rotation
88.960000000000065
Coordinate System Projection:
TAN
Quality
Full
FITS Header
Notes
Creator (Curator)
ESA/Hubble
URL
http://www.spacetelescope.org/
Name
Email
Telephone
Address
Karl-Schwarzschild-Strasse 2
City
Garching bei München
State/Province
Postal Code
D-85748
Country
Germany
Rights
Creative Commons Attribution 4.0 International License
Publisher
ESA/Hubble
Publisher ID
esahubble
Resource ID
potw1221a
Metadata Date
2012-04-24T15:50:27+02:00
Metadata Version
1.1
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Detailed color mapping information coming soon...

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There is no distance meta data in this image.

 

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