Messier 101: The Pinwheel Galaxy

Wise_wise2011-025_500

WISE_WISE2011-025 July 21st, 2011

Credit: NASA/JPL-Caltech/UCLA

A large spiral galaxy dominates this view from NASAs Wide-field Infrared Survey Explorer, or WISE. The galaxy, often called the Pinwheel galaxy, was designated object 101 in astronomer Charles Messiers catalog of fuzzy things in the sky that are not comets. Stargazers can find the galaxy with a pair of binoculars in the constellation Ursa Major (the Great Bear). It is located about 3.5 degrees east of the double stars Alcor & Mizar, the bend in the handle of the famous asterism the Big Dipper (an asterism is a pattern of stars in the sky, smaller than a constellation, that appear near each other but in fact are not associated together in space).

Messier 101 is a grand design spiral galaxy, which is a disk of hundreds of billions of stars with a small central bulge and prominent arms spiraling out from the center. In this case, we are seeing the disk face-on. In this image, stars appear blue because they are hotter and glow brightly in the shorter wavelengths observed by WISE. Cooler dust glows in the longer wavelengths seen by WISE, which are colored green and red here. The spiral arms contain slightly more stars than the rest of the disk, and most of the dust is concentrated in the arms as well. Along the spiral arms there are several bright spots colored red, including one that appears a short distance above and to the left of the galaxy. These are massive zones of star formation within the galaxy.

Messier 101 is a very large spiral galaxy. At nearly 200,000 light-years across it is about twice the size of our Milky Way Galaxy. Its high levels of star formation and very well-defined spiral arms are likely caused by gravitational interactions with neighboring galaxies.

One neighboring galaxy can be seen as a faint fuzzy purplish patch farther up and to the left of Messier 101, near the very top edge of the image. This is NGC 5477, an irregular dwarf galaxy that is probably associated with Messier 101. Another galaxy can also be seen in this view to the right of Messier 101 at the same height as the bright red spot at the bottom of M101, up and to the right of the bright star in that area. It appears as a fuzzy blue patch much smaller and fainter in appearance than Messier 101. This galaxy is cataloged as CGCG 272-018. While Messier 101 is about 24 million light-years away, CGCG 272-018 is much farther: about 92 million light-years away. When the light collected by WISE from CGCG 272-018 left this galaxy, dinosaurs still roamed the planet.

This image was made from observations by all four infrared detectors aboard WISE. Blue and cyan (blue-green) represent infrared light at wavelengths of 3.4 and 4.6 microns, which is primarily light from stars. Green and red represent light at 12 and 22 microns, which is primarily light from warm dust.

Image Source: /image/WISE/WISE2011-025

Curator: Wide-field Infrared Survey Explorer, Berkeley, CA, USA

Image Use Policy: Pulic Domain

Image Details

Image Type
Observation
Object Name
Pinwheel Galaxy Messier 101 M101 NGC 5457

Distance

Universescale2
23,000,000 light years
Wise_wise2011-025_128
 

Position Details

Position (ICRS)
RA = 14h 3m 12.7s
DEC = 54° 20’ 54.7”
Orientation
North is 42.5° CW
Field of View
43.6 x 43.6 arcminutes
Constellation
Ursa Major

Color Mapping

  Telescope Spectral Band Wavelength
Arrow_left_blue WISE Infrared (Near-IR) 3.4 µm
Arrow_left_cyan WISE Infrared (Near-IR) 4.6 µm
Arrow_left_green WISE Infrared (Mid-IR) 12.0 µm
Arrow_left_red WISE Infrared (Mid-IR) 22.0 µm
Spectrum_ir1
Arrow_top_blue
Arrow_top_cyan
Arrow_top_green
Arrow_top_red
Wise_wise2011-025_1280
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ID
WISE2011-025
Subject Category
Subject Name
Pinwheel Galaxy, Messier 101, M101, NGC 5457
Credits
NASA/JPL-Caltech/UCLA
Lightyears
23,000,000
Redshift
0.000804
Reference Url
/image/WISE/WISE2011-025
Type
Observation
Image Quality
Good
Distance Notes
Facility
WISE, WISE, WISE, WISE
Instrument
Color Assignment
Blue, Cyan, Green, Red
Band
Infrared, Infrared, Infrared, Infrared
Bandpass
Near-IR, Near-IR, Mid-IR, Mid-IR
Central Wavelength
3400, 4600, 12000, 22000
Start Time
Integration Time
Dataset ID
Notes
Coordinate Frame
ICRS
Equinox
Reference Value
210.8028101, 54.3485233
Reference Dimension
1900.0, 1900.0
Reference Pixel
951.0, 951.0
Scale
0.000382159, 0.0003821585
Rotation
-42.5
Coordinate System Projection:
SIN
Quality
Full
FITS Header
Notes
Creator (Curator)
Wide-field Infrared Survey Explorer
URL
http://wise.astro.ucla.edu
Name
Email
outreach@ssl.berkeley.edu
Telephone
Address
7 Gauss Way
City
Berkeley
State/Province
CA
Postal Code
94720
Country
USA
Rights
Pulic Domain
Publisher
Publisher ID
WISE
Resource ID
Resource URL
/image/WISE/WISE2011-025
Related Resources
Metadata Date
2012-10-12 16:49:04 -0700
Metadata Version
1.2
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Detailed color mapping information coming soon...

 

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Universescalefull
23,000,000 light years