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Collection:
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NASA Spitzer Space Telescope Collection
Collection
NASA Spitzer Space Telescope Collection
Collection
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Title:
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Messier 81
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Description:
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The magnificent spiral arms of the nearby galaxy Messier 81 are highlighted in this image from NASA's Spitzer Space Telescope. Located in the northern constellation of Ursa Major (which also includes the Big Dipper), this galaxy is easily visible through binoculars or a small telescope. M81 is located at a distance of 12 million light-years.
The main image is a composite mosaic obtained with the multiband imaging photometer and the infrared array camera. Thermal infrared emission at 24 microns detected by the photometer (red, bottom left inset) is combined with camera data at 8.0 microns (green, bottom center inset) and 3.6 microns (blue, bottom right inset).
A visible-light image of Messier 81, obtained with a ground-based telescope at Kitt Peak National Observatory, is shown in the upper right inset. Both the visible-light picture and the 3.6-micron near-infrared image trace the distribution of stars, although the Spitzer image is virtually unaffected by obscuring dust. Both images reveal a very smooth stellar mass distribution, with the spiral arms relatively subdued.
As one moves to longer wavelengths, the spiral arms become the dominant feature of the galaxy. The 8-micron emission is dominated by infrared light radiated by hot dust that has been heated by nearby luminous stars. Dust in the galaxy is bathed by ultraviolet and visible light from nearby stars. Upon absorbing an ultraviolet or visible-light photon, a dust grain is heated and re-emits the energy at longer infrared wavelengths. The dust particles are composed of silicates (chemically similar to beach sand), carbonaceous grains and polycyclic aromatic hydrocarbons and trace the gas distribution in the galaxy. The well-mixed gas (which is best detected at radio wavelengths) and dust provide a reservoir of raw materials for future star formation.
The 24-micron multiband imaging photometer image shows emission from warm dust heated by the most luminous young stars. The infrared-bright clumpy knots within the spiral arms show where massive stars are being born in giant H II (ionized hydrogen) regions. Studying the locations of these star forming regions with respect to the overall mass distribution and other constituents of the galaxy (e.g., gas) will help identify the conditions and processes needed for star formation.
Description
The magnificent spiral arms of the nearby galaxy Messier 81 are highlighted in this image from NASA's Spitzer Space Telescope. Located in the northern constellation of Ursa Major (which also includes the Big Dipper), this galaxy is easily visible through binoculars or a small telescope. M81 is located at a distance of 12 million light-years.
The main image is a composite mosaic obtained with the multiband imaging photometer and the infrared array camera. Thermal infrared emission at 24 microns detected by the photometer (red, bottom left inset) is combined with camera data at 8.0 microns (green, bottom center inset) and 3.6 microns (blue, bottom right inset).
A visible-light image of Messier 81, obtained with a ground-based telescope at Kitt Peak National Observatory, is shown in the upper right inset. Both the visible-light picture and the 3.6-micron near-infrared image trace the distribution of stars, although the Spitzer image is virtually unaffected by obscuring dust. Both images reveal a very smooth stellar mass distribution, with the spiral arms relatively subdued.
As one moves to longer wavelengths, the spiral arms become the dominant feature of the galaxy. The 8-micron emission is dominated by infrared light radiated by hot dust that has been heated by nearby luminous stars. Dust in the galaxy is bathed by ultraviolet and visible light from nearby stars. Upon absorbing an ultraviolet or visible-light photon, a dust grain is heated and re-emits the energy at longer infrared wavelengths. The dust particles are composed of silicates (chemically similar to beach sand), carbonaceous grains and polycyclic aromatic hydrocarbons and trace the gas distribution in the galaxy. The well-mixed gas (which is best detected at radio wavelengths) and dust provide a reservoir of raw materials for future star formation.
The 24-micron multiband imaging photometer image shows emission from warm dust heated by the most luminous young stars. The infrared-bright clumpy knots within the spiral arms show where massive stars are being born in giant H II (ionized hydrogen) regions. Studying the locations of these star forming regions with respect to the overall mass distribution and other constituents of the galaxy (e.g., gas) will help identify the conditions and processes needed for star formation.
Description
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Release Date:
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2003/12/18
Release_Date
2003/12/18
Release Date
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Press Release:
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Press_Release
Press Release
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Release Credit:
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NASA/JPL-Caltech/K. Gordon (University of Arizona) & S. Willner (Harvard-Smithsonian Center for Astrophysics), N.A. Sharp (NOAO/AURA/NSF)
Release_Credit
NASA/JPL-Caltech/K. Gordon (University of Arizona) & S. Willner (Harvard-Smithsonian Center for Astrophysics), N.A. Sharp (NOAO/AURA/NSF)
Release Credit
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Image Credit:
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NASA/JPL-Caltech/K. Gordon (University of Arizona) & S. Willner (Harvard-Smithsonian Center for Astrophysics), N.A. Sharp (NOAO/AURA/NSF)
Image_Credit
NASA/JPL-Caltech/K. Gordon (University of Arizona) & S. Willner (Harvard-Smithsonian Center for Astrophysics), N.A. Sharp (NOAO/AURA/NSF)
Image Credit
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Object name:
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M81
Object_name
M81
Object name
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Object name:
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NGC 3031
Object_name
NGC 3031
Object name
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Object name:
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Messier 81
Object_name
Messier 81
Object name
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Object name:
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UGC 5318
Object_name
UGC 5318
Object name
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Object type:
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Spiral galaxy
Object_type
Spiral galaxy
Object type
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Position (J2000):
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*RA: *09h55m33.20s *Dec: *69d03m55.00s
Position_(J2000)
*RA: *09h55m33.20s *Dec: *69d03m55.00s
Position (J2000)
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Distance:
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12,000,000 light-years (3.6 Mpc)
Distance
12,000,000 light-years (3.6 Mpc)
Distance
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Constellation:
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Ursa Major (the Big Bear)
Constellation
Ursa Major (the Big Bear)
Constellation
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Wavelength:
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3.6-4.5 (blue), 5.8-8.0 (green), 24 (red) microns
Wavelength
3.6-4.5 (blue), 5.8-8.0 (green), 24 (red) microns
Wavelength
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Image scale:
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23.3 x 17.8 arcmin [1.2 arcsec per pixel (IRAC)]
Image_scale
23.3 x 17.8 arcmin [1.2 arcsec per pixel (IRAC)]
Image scale
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Observers:
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Karl D. Gordon, Principal Investigator (University of Arizona)
Steven P. Willner, Principal Investigator (Harvard-Smithsonian Center for Astrophysics)
Almudena Alonso-Herroro (University of Arizona)
Philip Appleton (SSC/Caltech)
Matthew L. N. Ashby (Harvard-Smithsonian Center for Astrophysics)
Pauline Barmby (Harvard-Smithsonian Center for Astrophysics)
Chad Engelbracht (University of Arizona)
Giovanni G. Fazio (Harvard-Smithsonian Center for Astrophysics)
David Frayer (SSC/Caltech)
George Helou (SSC/Caltech)
Joannah Hinz (University of Arizona)
Robert Kennicutt (University of Arizona)
Karl Misselt (University of Arizona)
Michael A. Pahre (Harvard-Smithsonian Center for Astrophysics)
Pablo Perez-Gonzalez (University of Arizona)
George Rieke (University of Arizona)
Marcia Rieke (University of Arizona)
Susan Stolovy (SSC/Caltech)
Lisa Storrie-Lombardi (SSC/Caltech)
Observers
Karl D. Gordon, Principal Investigator (University of Arizona)
Steven P. Willner, Principal Investigator (Harvard-Smithsonian Center for Astrophysics)
Almudena Alonso-Herroro (University of Arizona)
Philip Appleton (SSC/Caltech)
Matthew L. N. Ashby (Harvard-Smithsonian Center for Astrophysics)
Pauline Barmby (Harvard-Smithsonian Center for Astrophysics)
Chad Engelbracht (University of Arizona)
Giovanni G. Fazio (Harvard-Smithsonian Center for Astrophysics)
David Frayer (SSC/Caltech)
George Helou (SSC/Caltech)
Joannah Hinz (University of Arizona)
Robert Kennicutt (University of Arizona)
Karl Misselt (University of Arizona)
Michael A. Pahre (Harvard-Smithsonian Center for Astrophysics)
Pablo Perez-Gonzalez (University of Arizona)
George Rieke (University of Arizona)
Marcia Rieke (University of Arizona)
Susan Stolovy (SSC/Caltech)
Lisa Storrie-Lombardi (SSC/Caltech)
Observers
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Instrument:
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IRAC MIPS
Instrument
IRAC MIPS
Instrument
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Exposure Date:
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November 6, 2003 (IRAC); November 24, 2003 (MIPS)
Exposure_Date
November 6, 2003 (IRAC); November 24, 2003 (MIPS)
Exposure Date
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Exposure Time:
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80 seconds per position (MIPS); 50 seconds per position (IRAC)
Exposure_Time
80 seconds per position (MIPS); 50 seconds per position (IRAC)
Exposure Time
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Orientation:
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North is rotated 91 degrees clockwise from the vertical
Orientation
North is rotated 91 degrees clockwise from the vertical
Orientation
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Magnitude:
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7.9
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Related links:
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Related_links
Related links
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note:
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*Multiwavelength composite image of M81* Screen-Resolution (450x341): JPEG [ http://ipac.jpl.nas…ssc2003-06d1_small.j pg ] High-Resolution (1158x878): JPEG | Mac TIFF | PC TIFF Credit: NASA/JPL-Caltech/K. Gordon (University of Arizona) & S. Willner (Harvard-Smithsonian Center for Astrophysics)
note
*Multiwavelength composite image of M81* Screen-Resolution (450x341): JPEG [ http://ipac.jpl.nas…ssc2003-06d1_small.j pg ] High-Resolution (1158x878): JPEG | Mac TIFF | PC TIFF Credit: NASA/JPL-Caltech/K. Gordon (University of Arizona) & S. Willner (Harvard-Smithsonian Center for Astrophysics) note
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note:
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*Visible-light comparison of M81* Screen-Resolution (450x341): JPEG [ http://ipac.jpl.nas…ssc2003-06d2_small.j pg ] High-Resolution (1158x878): JPEG | Mac TIFF | PC TIFF Credit: N.A. Sharp (NOAO/AURA/NSF)
note
*Visible-light comparison of M81* Screen-Resolution (450x341): JPEG [ http://ipac.jpl.nas…ssc2003-06d2_small.j pg ] High-Resolution (1158x878): JPEG | Mac TIFF | PC TIFF Credit: N.A. Sharp (NOAO/AURA/NSF) note
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note:
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*24-micron image of M81* Screen-Resolution (450x341): JPEG [ http://ipac.jpl.nas…ssc2003-06d3_small.j pg ] High-Resolution (1158x878): JPEG | Mac TIFF | PC TIFF Credit: NASA/JPL-Caltech/K. Gordon (University of Arizona) & S. Willner (Harvard-Smithsonian Center for Astrophysics)
note
*24-micron image of M81* Screen-Resolution (450x341): JPEG [ http://ipac.jpl.nas…ssc2003-06d3_small.j pg ] High-Resolution (1158x878): JPEG | Mac TIFF | PC TIFF Credit: NASA/JPL-Caltech/K. Gordon (University of Arizona) & S. Willner (Harvard-Smithsonian Center for Astrophysics) note
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note:
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*8-micron image of M81* Screen-Resolution (450x341): JPEG [ http://ipac.jpl.nas…ssc2003-06d4_small.j pg ] High-Resolution (1158x878): JPEG | Mac TIFF | PC TIFF Credit: NASA/JPL-Caltech/K. Gordon (University of Arizona) & S. Willner (Harvard-Smithsonian Center for Astrophysics)
note
*8-micron image of M81* Screen-Resolution (450x341): JPEG [ http://ipac.jpl.nas…ssc2003-06d4_small.j pg ] High-Resolution (1158x878): JPEG | Mac TIFF | PC TIFF Credit: NASA/JPL-Caltech/K. Gordon (University of Arizona) & S. Willner (Harvard-Smithsonian Center for Astrophysics) note
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note:
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*3.6-micron image of M81* Screen-Resolution (450x341): JPEG [ http://ipac.jpl.nas…ssc2003-06d5_small.j pg ] High-Resolution (1158x878): JPEG | Mac TIFF | PC TIFF Credit: NASA/JPL-Caltech/K. Gordon (University of Arizona) & S. Willner (Harvard-Smithsonian Center for Astrophysics)
note
*3.6-micron image of M81* Screen-Resolution (450x341): JPEG [ http://ipac.jpl.nas…ssc2003-06d5_small.j pg ] High-Resolution (1158x878): JPEG | Mac TIFF | PC TIFF Credit: NASA/JPL-Caltech/K. Gordon (University of Arizona) & S. Willner (Harvard-Smithsonian Center for Astrophysics) note
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facet_what:
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Spitzer Space Telescope
facet_what
Spitzer Space Telescope
facet_what
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facet_what:
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Visible Light
facet_what
Visible Light
facet_what
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facet_what:
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TRACE
facet_what
TRACE
facet_what
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facet_what:
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MIPS
facet_what
MIPS
facet_what
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facet_what:
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Ursa Major
facet_what
Ursa Major
facet_what
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facet_what:
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Aura
facet_what
Aura
facet_what
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facet_what:
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Messier
facet_what
Messier
facet_what
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facet_what:
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Messier 81
facet_what
Messier 81
facet_what
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facet_what:
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Infrared Array Camera (IRAC)
facet_what
Infrared Array Camera (IRAC)
facet_what
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facet_where:
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Arizona
facet_where
Arizona
facet_where
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facet_where:
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M81
facet_where
M81
facet_where
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facet_where:
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NGC 3031
facet_where
NGC 3031
facet_where
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facet_where:
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Chad
facet_where
Chad
facet_where
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facet_where:
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Jet Propulsion Laboratory (JPL)
facet_where
Jet Propulsion Laboratory (JPL)
facet_where
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facet_where:
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Washington, D.C.
facet_where
Washington, D.C.
facet_where
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facet_where:
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Stennis Space Center (SSC)
facet_where
Stennis Space Center (SSC)
facet_where
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facet_when:
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November 6, 2003
facet_when
November 6, 2003
facet_when
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facet_when:
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November 24, 2003
facet_when
November 24, 2003
facet_when
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facet_when_year:
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2003
facet_when_year
2003
facet_when_year
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Image #:
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ssc2003-06d
Image_#
ssc2003-06d
Image #
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original url:
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original_url
original url
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UID:
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SPD-SPITZ-ssc2003-06 d
UID
SPD-SPITZ-ssc2003-06 d
UID
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