NGC 300

NGC300 - Spitzer Space Telescope - Ssc2004-07b1.tif
Sometimes, the best way to understand how something works is to take it apart. The same is true for galaxies like NGC 300, which NASA's Spitzer Space Telescope has divided into its various parts. NGC 300 is a face-on spiral galaxy located 7.5 million light-years away in the southern constellation Sculptor.

This false-color image taken by the infrared array camera on Spitzer readily distinguishes the main star component of the galaxy (blue) from its dusty spiral arms (red). The star distribution peaks strongly in the central bulge where older stars congregate, and tapers off along the arms where younger stars reside.

Thanks to Spitzer's unique ability to sense the heat or infrared emission from dust, astronomers can now clearly trace the embedded dust structures within NGC 300's arms. When viewed at visible wavelengths, the galaxy's dust appears as dark lanes, largely overwhelmed by bright starlight. With Spitzer, the dust -- in particular organic compounds called polycyclic aromatic hydrocarbons -- can be seen in vivid detail (red). These organic molecules are produced, along with heavy elements, by the stellar nurseries that pepper the arms.

The findings provide a better understanding of spiral galaxy mechanics and, in the future, will help decipher more distant galaxies, whose individual components cannot be resolved.

This image was taken on Nov. 21, 2003 and is composed of photographs obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).

View of the southern spiral NGC 300.jpg
Autor/Urheber: ESO, Lizenz: CC BY 4.0
This picture of the spectacular southern spiral galaxy NGC 300 was taken using the Wide Field Imager (WFI) at ESO’s La Silla Observatory in Chile. It was assembled from many individual images through a large set of different filters over many observing nights, spanning several years. The main purpose of this extensive observational campaign was to get an unusually thorough census of the stars in the galaxy, counting both the number and varieties of stars and marking regions, or even individual stars, that warrant deeper and more focussed investigation. But such a rich data collection will also have many other uses for years to come. The images were mostly taken through filters that transmit red, green or blue light. These were supplemented by images through special filters that allow through only the light from ionised hydrogen or oxygen gas and highlight the glowing clouds in the galaxy’s spiral arms. The total exposure time amounted to around 50 hours.

NGC300 - HST - Opo0413c.tif
(c) ESA/Hubble, CC BY 4.0

Hubble sees stars as numerous as grains of sand in nearby galaxy

Myriads of stars embedded in the heart of the nearby galaxy NGC 300 can be singled out like grains of sand on a beach in this Hubble Space Telescope image. The Hubble telescope's exquisite resolution enables it to see the stars as individual points of light, despite the fact that the galaxy is millions of light-years away.

NGC 300 is a spiral galaxy similar to our own Milky Way galaxy. It is a member of a nearby group of galaxies known as the Sculptor group, named for the southern constellation where the group can be found. The distance to NGC 300 is 6.5 million light-years, making it one of the Milky Way's closer neighbors. At this distance, only the brightest stars can be picked out from ground-based images. With a resolution some 10 times better than ground-based telescopes, Hubble's Advanced Camera for Surveys (ACS) resolves many more stars in this galaxy than can be detected from the ground.

The colour composite was made from filtered images taken in blue, green, and infrared light. Hot, young blue stars appear in clusters that form in the galaxy's spiral arms. Ribbons of deep red stars mark the location of gauzy curtains of dust that partially hide the light of the stars behind them. Near the center of the image is the bright and compact nucleus of the galaxy where even the ACS loses the ability to separate the densely packed stars.

The individual exposures that were combined to make this new image were taken in July and September 2002. These Hubble data are being used to test a new method for measuring distances to galaxies and to compare it with the more traditional methods, such as the period-luminosity relationship of pulsating stars known as Cepheid variables. Measuring distances is a perpetual but important concern for astronomers.

Some of the luminous blue specks in this image, young and massive stars called blue supergiants, are among the brightest stars seen in spiral galaxies like NGC 300. By combining the stellar brightness with other information, such as the stellar temperature, surface gravity and mass outflow, astronomers are defining a new technique to measure distances to galaxies located millions of light-years away.

Credit:

NASA, ESA, and The Hubble Heritage Team (AURA/STScI)

Coordinates
Position (RA): 	0 54 54.09
Position (Dec):	-37° 40' 58.49"
Field of view:  	2.95 x 4.66 arcminutes
Orientation:    	North is 171.8° right of vertical

Colours & filters Band	Wavelength	Telescope
Optical          B	435 nm	Hubble Space Telescope ACS
Optical          V	555 nm	Hubble Space Telescope ACS
Infrared         I	814 nm	Hubble Space Telescope ACS

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Caldwell Catalogue.jpg
Autor/Urheber: Roberto Mura, Lizenz: CC BY-SA 3.0
Caldwell Catalogue objects.

Galaxy NGC 300 (29976342992).jpg
Autor/Urheber: NASA on The Commons, Lizenz: No restrictions

This image of the nearby spiral galaxy NGC 300 was taken by Galaxy Evolution Explorer in a single orbit exposure of 27 minutes.NGC 300 lies 7 million light years from our Milky Way galaxy and is one of a group of galaxies in the constellation Sculptor. NGC 300 is often used as a prototype of a spiral galaxy because in optical images it displays flowing spiral arms and a bright central region of older (and thus redder) stars.

Image #: PIA04924

Date: October 10, 2003