WISE Spies a Galactic Neighbor

Wise_wise2010-047_500

WISE_WISE2010-047 December 28th, 2010

Credit: NASA/JPL-Caltech/UCLA

This image captured by NASAs Wide-field Infrared Survey Explorer, or WISE, shows of one of our closest neighboring galaxies, Messier 33. Also named the Triangulum Galaxy (after the constellation its found in), M33 is one of largest members in our small neighborhood of galaxies -- the Local Group. The Local Group consists of about 30 galaxies that are gravitationally bound and travel together through the Universe. M33 is the third largest member of the Local Group, dwarfed only by the Andromeda Galaxy (M31) and our very own home galaxy, the Milky Way.

M33 is extremely close as far as galaxies go, residing only 3 million light years away. Its proximity, along with it being conveniently tilted towards Earth (about 54 degrees to the line of sight), make it very easy for astronomers to study in detail. The infrared images that WISE produces contribute to astronomers overall understanding of a variety of processes happening in the galaxy. Areas in the spiral arms that are hidden behind dust in visible light shine through brightly in infrared light, showing where clouds of cool gas are concentrated. Star-forming regions are easy to spot in infrared (green and red areas in this image). Notice that there isnt a lot of star formation occurring near the center of M33. It would be difficult to deduce this lack of activity in the core by only looking a visible light image, where the core appears to be the brightest feature. This infrared image also shows that the galaxy is surprisingly bigger than it appears in visible light. The cold dust seen by WISE extends much further out from the core than anticipated.

The bright yellow-orange blobs scattered throughout M33 are areas where stars are forming at an especially intense rate. The largest one in the spiral arm to the upper left has its own name, NGC 604. Its an H II region -- an area of gas that is being heated and ionized by powerful young stars recently born inside of it. The Orion Nebula is an example of a nearby H II region within our own Milky Way Galaxy. NGC 604, however, is the largest such region in the entire Local Group of galaxies. It is over 40 times larger than the Orion Nebula and much brighter. If NGC 604 were at the same distance from Earth as the Orion Nebula it would be the brightest object in the night sky (besides the Moon).

M33 is over 50,000 light years across (about half the size of the Milky Way). Because it is so close it appears quite large to us, covering a piece of sky nearly 4 times bigger than the full Moon. Its relatively low surface brightness makes it difficult for human eyes to see, however. Even so, under exceptionally dark skies it can be seen with the unaided eye, making it one of the furthest objects visible without a telescope.

These images were made from observations by all four infrared detectors aboard WISE. Blue and cyan 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 emitted from warm dust.

Image Source: /image/WISE/WISE2010-047

Curator: Spitzer Space Telescope, Pasadena, CA, USA

Image Use Policy: Public Domain

Image Details

Image Type
Observation
Object Name
Triangulum Galaxy Messier 33 M33 NGC 598
Subject - Milky Way
Galaxy » Type » Spiral

Distance

Universescale2
2,500,000 light years
Wise_wise2010-047_128
 

Position Details

Position (ICRS)
RA = 1h 33m 46.4s
DEC = 30° 40’ 10.3”
Orientation
North is 0.5° CW
Field of View
1.5 x 1.5 degrees
Constellation
Triangulum

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_wise2010-047_1280
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ID
WISE2010-047
Subject Category
B.5.1.1.  
Subject Name
Triangulum Galaxy, Messier 33, M33, NGC 598
Credits
NASA/JPL-Caltech/UCLA
Lightyears
2,500,000
Redshift
Reference Url
/image/WISE/WISE2010-047
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
J2000
Reference Value
23.4431621, 30.6695389
Reference Dimension
4000.0, 4000.0
Reference Pixel
2002.0, 2000.0
Scale
0.000381976, 0.000381976
Rotation
-0.53
Coordinate System Projection:
TAN
Quality
Full
FITS Header
Notes
WCS retrieved using CXCs PinpointWCS
Creator (Curator)
Spitzer Space Telescope
URL
http://www.spitzer.caltech.edu
Name
Email
Telephone
Address
1200 E. California Blvd.
City
Pasadena
State/Province
CA
Postal Code
91125
Country
USA
Rights
Public Domain
Publisher
Publisher ID
WISE
Resource ID
Resource URL
/image/WISE/WISE2010-047
Related Resources
Metadata Date
2012-10-12 16:56:13 -0700
Metadata Version
1.1
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Detailed color mapping information coming soon...

 

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Universescalefull
2,500,000 light years