NASA's Hubble Space Telescope snapped a view of what may be the youngest galaxy ever seen. This "late bloomer" may not have begun active star formation until about 13 billion years after the Big Bang. Called I Zwicky 18 [below, left], the galaxy may be as young as 500 million years old. This youngster has gone though several sudden bursts of star formation - the first only some 500 million years ago and the latest only 4 million years ago. This galaxy is typical of the kinds of galaxies that inhabited the early universe. The galaxy is classified as a dwarf irregular galaxy and is much smaller than our Milky Way.
The two major starburst regions are the concentrated bluish-white knots embedded in the heart of the galaxy. The wispy blue filaments surrounding the central starburst region are bubbles of gas that have been heated by stellar winds and intense ultraviolet radiation unleashed by hot, young stars. The redder stars are slightly older stars and star clusters, but they are still less than 1 billion years old. A companion galaxy lies just above and to the right of the dwarf galaxy. The companion may be interacting with the dwarf galaxy and may have triggered that galaxy's recent star formation. The red blobs surrounding the dwarf galaxy are the dim glow from ancient fully formed galaxies.
This image was taken with Hubble's Advanced Camera for Surveys in 2003.
Credits
NASA, ESA, Y. Izotov (Main Astronomical Observatory, Kyiv, UA) and T. Thuan (University of Virginia)| About The Object | |
|---|---|
| Object Name | I Zwicky 18, I Zw 18 |
| Object Description | Irregular Dwarf Galaxy |
| R.A. Position | 09h 34m 0.9s |
| Dec. Position | 55° 14' 34.19" |
| Constellation | Ursa Major |
| Distance | 45 million light-years (14 Megaparsecs) |
| Dimensions | This image is 50 arcseconds (11,000 light-years or 3.3 kiloparsecs) wide. |
| About The Data | |
| Data Description | The Hubble image was created from HST data from proposal : T. Thuan (Univ. of Virginia) and Y. Izotov (Main Astronomical Observatory, Kyiv, UA). The Hubble NICMOS data are from the following HST proposals: and : G. Ostlin (Stockholm Univ.), N. Bergvall, A. Hidalgo Gamez, and K. Olofsson (Uppsala Astronomical Observatory), and J. Rönnback (Uppsala Univ.). The science team is comprised of G. Ostlin of (Stockholm Observatory) and M. Mouhcine (Univ. of Nottingham). |
| Instrument | HST>ACS/WFC and HST>NICMOS |
| Exposure Dates | May 26 – June 6, 2003, Exposure Time: 19 hours (ACS); December 28, 1997; Feb 15/22, 1998, Exposure Time: 12 hours (NICMOS) |
| Filters | ACS: F555W (V) and F814W (I) NICMOS: F110W (J) F160W (H), F205W (K), F171M (1.68-1.76 µm) and F180M (1.76-1.83 µm) |
| About The Image | |
| Color Info | Blue: WFPC2 F450W (B) Green: ACS F555W (V) Red: ACS 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. |
