First Peek at Spitzer's Legacy: Mysterious Whirlpool Galaxy
title
First Peek at Spitzer's Legacy: Mysterious Whirlpool Galaxy
Title
false
Description:
NASA's Spitzer Space Telescope has captured these infrared images of the "Whirlpool Galaxy," revealing strange structures bridging the gaps between the dust-rich spiral arms, and tracing the dust, gas and stellar populations in both the bright spiral galaxy and its companion. The Spitzer image is a four-color composite of invisible light, showing emissions from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8.0 microns (red). These wavelengths are roughly 10 times longer than those seen by the human eye. The visible light image comes from the Kitt Peak National Observatory 2.1m telescope, and has the same orientation and size as the Spitzer infrared image, measuring 9.9 by 13.7 arcminutes (north up). Also a four-color composite, the visible light image shows emissions from 0.4 to 0.7 microns, including the H-alpha nebular feature (red in the image). The light seen in the images originates from very different sources. At shorter wavelengths (in the visible bands, and in the infrared from 3.6 to 4.5 microns), the light comes mainly from stars. This starlight fades at longer wavelengths (5.8 to 8.0 microns), where we see the glow from clouds of interstellar dust. This dust consists mainly of a variety of carbon-based organic molecules known collectively as polycyclic aromatic hydrocarbons. Wherever these compounds are found, there will also be dust granules and gas, which provide a reservoir of raw materials for future star formation. Particularly puzzling are the large number of thin filaments of red emission seen in the infrared data between the arms of the large spiral galaxy. In contrast to the beady nature of the dust emission seen in the arms themselves, these spoke-like features are thin and regular, and prevalent in the gaps all over the face of the galaxy. Also of interest is the contrast in the distributions of dust and stars between the spiral and its faint companion. While the spiral is rich in dust, bright in the longer infrared wavebands, and actively forming new stars, its blue companion shows little infrared emission and hosts an older stellar population. The spectacular whirlpool structure and star formation in M51 are thought to be triggered by an ongoing collision with its companion. Understanding the impact on star formation by the interaction of galaxies is one of the goals of these observations. The targeted galaxy is known by various names: M51 from its Messier catalog designation, and also as NGC 5194. M51 was one of the original discoveries of Charles Messier, found in October 1773 while he was observing a faint comet. The Messier catalogue of galaxies is named after him. Colloquially, M51 is also known as the "Whirlpool Galaxy", or "Rosse's Galaxy," after Lord Rosse, who first detected galaxy spiral structure in his observations of M51. The companion, NGC 5195, was discovered in 1781 by Pierre Mechain. The Whirlpool galaxy is a favorite target for amateur and professional
description
NASA's Spitzer Space Telescope has captured these infrared images of the "Whirlpool Galaxy," revealing strange structures bridging the gaps between the dust-rich spiral arms, and tracing the dust, gas and stellar populations in both the bright spiral galaxy and its companion. The Spitzer image is a four-color composite of invisible light, showing emissions from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8.0 microns (red). These wavelengths are roughly 10 times longer than those seen by the human eye. The visible light image comes from the Kitt Peak National Observatory 2.1m telescope, and has the same orientation and size as the Spitzer infrared image, measuring 9.9 by 13.7 arcminutes (north up). Also a four-color composite, the visible light image shows emissions from 0.4 to 0.7 microns, including the H-alpha nebular feature (red in the image). The light seen in the images originates from very different sources. At shorter wavelengths (in the visible bands, and in the infrared from 3.6 to 4.5 microns), the light comes mainly from stars. This starlight fades at longer wavelengths (5.8 to 8.0 microns), where we see the glow from clouds of interstellar dust. This dust consists mainly of a variety of carbon-based organic molecules known collectively as polycyclic aromatic hydrocarbons. Wherever these compounds are found, there will also be dust granules and gas, which provide a reservoir of raw materials for future star formation. Particularly puzzling are the large number of thin filaments of red emission seen in the infrared data between the arms of the large spiral galaxy. In contrast to the beady nature of the dust emission seen in the arms themselves, these spoke-like features are thin and regular, and prevalent in the gaps all over the face of the galaxy. Also of interest is the contrast in the distributions of dust and stars between the spiral and its faint companion. While the spiral is rich in dust, bright in the longer infrared wavebands, and actively forming new stars, its blue companion shows little infrared emission and hosts an older stellar population. The spectacular whirlpool structure and star formation in M51 are thought to be triggered by an ongoing collision with its companion. Understanding the impact on star formation by the interaction of galaxies is one of the goals of these observations. The targeted galaxy is known by various names: M51 from its Messier catalog designation, and also as NGC 5194. M51 was one of the original discoveries of Charles Messier, found in October 1773 while he was observing a faint comet. The Messier catalogue of galaxies is named after him. Colloquially, M51 is also known as the "Whirlpool Galaxy", or "Rosse's Galaxy," after Lord Rosse, who first detected galaxy spiral structure in his observations of M51. The companion, NGC 5195, was discovered in 1781 by Pierre Mechain. The Whirlpool galaxy is a favorite target for amateur and professional
Description
false
Release Date:
11/05/04
release_date
11/05/04
Release Date
false
Press Release:
First Peek at Spitzer's Legacy: Mysterious Whirlpool Galaxy [ http://www.spitzer.… ]
press_release
First Peek at Spitzer's Legacy: Mysterious Whirlpool Galaxy [ http://www.spitzer.caltech.edu/Media/releases/ssc2004-19/ssc2004-19a.shtml ]
Press Release
false
Release Credit:
NASA/JPL-Caltech/R. Kennicutt (Univ. of Arizona)/DSS
release_credit
NASA/JPL-Caltech/R. Kennicutt (Univ. of Arizona)/DSS
Release Credit
false
Image Credit:
R. Kennicutt (Steward Observatory, Univ. of Arizona)
image_credit
R. Kennicutt (Steward Observatory, Univ. of Arizona)
Robert Kennicutt, Principal Investigator (Steward Observatory, University of Arizona) Lee Armus (Spitzer Science Center, Caltech) George Bendo (Steward Observatory, University of Arizona) Daniela Calzetti (Space Telescope Science Institute) Daniel Dale (University of Wyoming) Bruce Draine (Princeton University) Charles Engelbracht (Steward Observatory, University of Arizona) Karl Gordon (Steward Observatory, University of Arizona) George Helou (Caltech) David Hollenbach (NASA Ames Research Center) Thomas Jarrett (Caltech) Lisa Kewley (Harvard Center for Astrophysics) Claus Leitherer (Space Telescope Science Institute) Aigen Li (Steward Observatory, University of Arizona) Sangeeta Malhotra (Space Telescope Science Institute) Martin Meyer (Space Telescope Science Institute) Eric Murphy (Yale University) Michael Regan (Space Telescope Science Institute) George Rieke (Steward Observatory, University of Arizona) Marcia Rieke (Steward Observatory, University of Arizona) Helene Roussel (Caltech) John-David Smith (Steward Observatory, University of Arizona) Michele D. Thornley (Bucknell University, Space Telescope Science Institute) Fabian Walter (National Radio Astronomy Observatory)
observers
Robert Kennicutt, Principal Investigator (Steward Observatory, University of Arizona) Lee Armus (Spitzer Science Center, Caltech) George Bendo (Steward Observatory, University of Arizona) Daniela Calzetti (Space Telescope Science Institute) Daniel Dale (University of Wyoming) Bruce Draine (Princeton University) Charles Engelbracht (Steward Observatory, University of Arizona) Karl Gordon (Steward Observatory, University of Arizona) George Helou (Caltech) David Hollenbach (NASA Ames Research Center) Thomas Jarrett (Caltech) Lisa Kewley (Harvard Center for Astrophysics) Claus Leitherer (Space Telescope Science Institute) Aigen Li (Steward Observatory, University of Arizona) Sangeeta Malhotra (Space Telescope Science Institute) Martin Meyer (Space Telescope Science Institute) Eric Murphy (Yale University) Michael Regan (Space Telescope Science Institute) George Rieke (Steward Observatory, University of Arizona) Marcia Rieke (Steward Observatory, University of Arizona) Helene Roussel (Caltech) John-David Smith (Steward Observatory, University of Arizona) Michele D. Thornley (Bucknell University, Space Telescope Science Institute) Fabian Walter (National Radio Astronomy Observatory)
Observers
false
Instrument:
IRAC
instrument
IRAC
Instrument
false
Exposure Date:
March 28-29, 2003
exposure_date
March 28-29, 2003
Exposure Date
false
Exposure Time:
12 min (B,V), 6 min (R), 30 min (H-alpha)
exposure_time
12 min (B,V), 6 min (R), 30 min (H-alpha)
Exposure Time
false
Orientation:
North is up
orientation
North is up
Orientation
false
Magnitude:
8.4
magnitude
8.4
Magnitude
false
note:
*Spitzer image* Screen-Resolution (326x450): JPEG [ http://ipac.jpl.nas… ssc2004-19a2_small.jpg ] High-Resolution (1551x2142): JPEG | Mac TIFF | PC TIFF Credit: NASA/JPL-Caltech/R. Kennicutt (Univ. of Arizona)
note
*Spitzer image* Screen-Resolution (326x450): JPEG [ http://ipac.jpl.nasa.gov/media_images/ ssc2004-19a2_small.jpg ] High-Resolution (1551x2142): JPEG | Mac TIFF | PC TIFF Credit: NASA/JPL-Caltech/R. Kennicutt (Univ. of Arizona)