These images, taken by NASA's Hubble Space Telescope, show myriad stars residing in the central regions of the three dwarf galaxies NGC 4163, NGC 4068, and IC 4662.
The bluish dots are younger stars; the reddish dots, older stars. The irregularly shaped red blobs in the images of NGC 4163 and IC 4662 are regions of current starburst activity. Starbursts are areas of intense star formation.
The three galaxies are part of a Hubble study of starbursts in nearby, small, or dwarf, galaxies. Based on this study, astronomers have found that starbursts continue 100 times longer than first thought, lasting 200 million to 400 million years. These galaxies show that starbursts are not isolated events, but sweep across a galaxy.
Each of the three starburst galaxies has a different shape. The collection of stars in NGC 4163 is more spherical, with a higher concentration of stars forming in the center. By contrast, the grouping of stars in NGC 4068 is more elongated and has fewer new stars than the other two galaxies. Astronomers think the starburst in this galaxy is ending. In the image of IC 4662 the clumpy red blobs peppered throughout the galaxy indicate active regions of star birth. One such region extends off the image's top, right edge. This galaxy exhibits the strongest star formation of the three galaxies in the study.
The distances of the galaxies range from 8 million to 14 million light-years away.
The images were taken in 2004 by the Advanced Camera for Surveys.
Credits
NASA, ESA, K. McQuinn (University of Minnesota, Minneapolis), and I. Karachentsev (Special Astrophysical Observatory of the Russian Academy of Sciences, Russia)| About The Object | |
|---|---|
| Object Name | NGC 4163, NGC 4068, IC 4662 |
| Object Description | Starburst Galaxies |
| About The Data | |
| Data Description | The images were created from Hubble data from proposal : I. Karachentsev (Russian Academy of Sciences, Special Astrophysical Observatory), B. Tully (University of Hawaii), V. Karachentseva (Kyiv University), A. Dolphin (Raytheon Company), S. Sakai (University of California, Los Angeles), E. Shaya (University of Maryland), and M. Sharina, L. Makarova, and D. Makarov (Russian Academy of Sciences, Special Astrophysical Observatory). The science team comprises: K. McQuinn and E. Skillman (University of Minnesota, Minneapolis), J. Cannon (Macalester College, MN), J. Dalcanton (University of Washington, Seattle), A. Dolphin (Raytheon Company), and D. Stark and D. Weisz (University of Minnesota, Minneapolis). |
| Instrument | HST>ACS |
| Exposure Dates | January 18, 2004 (left), March 28, 2004 (center), and July 10, 2004 (right), Exposure Time: 35 minutes per image |
| Filters | F606W (R) and F814W (I) |
| About The Image | |
| Color Info | These images are composites of several separate exposures made by the ACS instrument on the Hubble Space Telescope. Two filters were used to sample broad wavelength ranges for each image. The color results from assigning different hues (colors) to each monochromatic image. In this case, the assigned colors are orange/yellow for the I-band (F814W) and cyan/blue for the wide V-band (F606W) filter. The images have been further adjusted so the colors more closely resemble their true visual appearance, particularly the red hydrogen emission of the star-forming regions. Cyan: F606W (R) Yellow: F814W (I) |
| Compass Image |  |
| About The Object | |
|---|---|
| Object Name | A name or catalog number that astronomers use to identify an astronomical object. |
| Object Description | The type of astronomical object. |
| R.A. Position | Right ascension – analogous to longitude – is one component of an object's position. |
| Dec. Position | Declination – analogous to latitude – is one component of an object's position. |
| Constellation | One of 88 recognized regions of the celestial sphere in which the object appears. |
| Distance | The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs. |
| Dimensions | The physical size of the object or the apparent angle it subtends on the sky. |
| About The Data | |
| Data Description |
|
| Instrument | The science instrument used to produce the data. |
| Exposure Dates | The date(s) that the telescope made its observations and the total exposure time. |
| Filters | The camera filters that were used in the science observations. |
| About The Image | |
| Image Credit | The primary individuals and institutions responsible for the content. |
| Publication Date | The date and time the release content became public. |
| Color Info | A brief description of the methods used to convert telescope data into the color image being presented. |
| Orientation | The rotation of the image on the sky with respect to the north pole of the celestial sphere. |
