Blaze of stars in an old galaxy's core

Esahubble_heic0302a_1024

esahubble_heic0302a March 6th, 2003

Credit: NASA, ESA and the Hubble Heritage Team STScI/AURA )

The central region of the small galaxy NGC 1705 blazes with the light of thousands of young and old stars. Astronomers call NGC 1705 a dwarf irregular, that is, a small galaxy lacking regular structure. Knowing how dwarf irregular galaxies evolve tells us a lot about galaxy formation and evolution. At 17 million light-years away, the individual stars of the galaxy NGC 1705 are out of range of all but the sharp eyes of the NASA/ESA Hubble Space Telescope. NGC 1705 is an ideal laboratory to conduct investigations on the history of star formation. Young, blue, hot stars are strongly concentrated toward the galaxy's centre. Older, red, cooler stars are more spread out. This galaxy has been forming new stars throughout its lifetime, but a burst of star-formation activity occurred as recently as 26 to 31 million years ago. This 'starburst' is responsible for many of the young stars on the outskirts of this galaxy's core as well as the central giant star cluster. Many astronomers now believe that dwarf galaxies were the first galaxies to collapse and start forming stars in the early Universe. They represent the building blocks from which more massive objects (spiral and elliptical galaxies) later formed. Nearby small galaxies are thought to be the leftovers of the galaxy-formation process. Dwarf irregular galaxies are probably fairly old stellar systems whose chemical and physical properties may be the result of the process of slow evolution. The Hubble observations of the stars in NGC 1705 and other close irregulars show that these galaxies are several thousand million years old. NGC 1705 could be as old as 13.5 thousand million years. Dwarf irregulars are similar in many ways to very young galaxies, but they are much nearer and easier to study. These galaxies seem to have consumed only a tiny part of their reservoir of gas. Their stars have a much lower fraction of heavy elements than does the Sun. Astronomers therefore think that only a few generations of stars have formed there over time. NGC 1705's age, its irregular shape, and proximity all make it an excellent source of knowledge about galaxy formation and evolution. This image was taken in March 1999 and November 2000 by an international science team led by Monica Tosi at Italy's National Institute of Astrophysics (INAF) at the Osservatorio Astronomico di Bologna. Other team members include Alessandra Aloisi (JHU), Mark Clampin (STScI), Laura Greggio (INAF, Osservatorio Astronomico di Padova), Claus Leitherer and Antonella Nota (STScI). Hubble's Wide Field Planetary Camera 2 observed the galaxy in ultraviolet, blue, visible, and infrared light. Although not included in this image, NICMOS (Near Infrared Camera and Multi Object Spectrometer) observations were also made of the galaxy's central core.

Provider: Hubble Space Telescope | ESA

Image Source: http://www.spacetelescope.org/images/heic0302a/

Curator: ESA/Hubble, Garching bei München, Germany

Image Use Policy: Creative Commons Attribution 4.0 International License

Image Details

Image Type
Observation
Object Name
IRAS 04531-5326 NGC 1705
Subject - Local Universe
Galaxy > Type > Irregular
Galaxy > Size > Dwarf
Esahubble_heic0302a_128
 

Position Details

Position (ICRS)
RA = 4h 54m 13.5s
DEC = -53° 21’ 40.9”
Orientation
North is 44.8° CW
Field of View
0.5 x 0.6 arcminutes
Constellation
Pictor

Color Mapping

  Telescope Spectral Band Wavelength
Hubble (WFPC2) Ultraviolet (U) 380.0 nm
Hubble (WFPC2) Optical (B) 439.0 nm
Hubble (WFPC2) Optical (V) 555.0 nm
Hubble (WFPC2) Infrared (I) 814.0 nm
Spectrum_base
Esahubble_heic0302a_1280
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ID
heic0302a
Subject Category
C.5.1.6   C.5.2.2  
Subject Name
IRAS 04531-5326, NGC 1705
Credits
NASA, ESA and the Hubble Heritage Team STScI/AURA )
Release Date
2003-03-06T15:00:00
Lightyears
Redshift
Reference Url
http://www.spacetelescope.org/images/heic0302a/
Type
Observation
Image Quality
Distance Notes
Distance in light years from NED
Facility
Hubble Space Telescope, Hubble Space Telescope, Hubble Space Telescope, Hubble Space Telescope
Instrument
WFPC2, WFPC2, WFPC2, WFPC2
Color Assignment
Band
Ultraviolet, Optical, Optical, Infrared
Bandpass
U, B, V, I
Central Wavelength
380, 439, 555, 814
Start Time
Integration Time
Dataset ID
Notes
Coordinate Frame
ICRS
Equinox
J2000
Reference Value
73.5561950317, -53.3613671442
Reference Dimension
627.0, 760.0
Reference Pixel
313.5, 380.0
Scale
-1.26297564913e-05, 1.26297564913e-05
Rotation
-44.820000000000007
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
heic0302a
Metadata Date
2003-12-09T17:09:57+01:00
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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