This color image from the Hubble Space Telescope shows a region in NGC 1365, a barred spiral galaxy located in a cluster of galaxies called Fornax. A barred spiral galaxy is characterized by a "bar" of stars, dust and gas across its center. The black and white photograph from a ground-based telescope shows the entire galaxy, which is visible from the Southern Hemisphere. Members of the Key Project team, who have been measuring the distance to the Fornax cluster, have estimated it to be 60 million light-years from Earth. The team arrived at their preliminary estimate by using Cepheids, bright, young stars that are used as milepost markers to calculate distances to nearby galaxies. The line of small blue dots in the color image shows the formation of stars in the galaxy's spiral arms, making them ideal targets for the discovery of Cepheids. The group has discovered about 50 Cepheids in the galaxy. The team also has used the Fornax cluster to calibrate and compare many secondary distance methods. Cepheids are accurate distance markers for nearby galaxies, but astronomers need secondary methods to measure distances to faraway galaxies. An accurate value for the Hubble Constant is dependent on reliable secondary distance methods.
Credits
W. Freedman (Carnegie Observatories), the Hubble Space Telescope Key Project team and NASA| About The Object | |
|---|---|
| Object Name | NGC 1365 |
| R.A. Position | 03h 33m 36.49s |
| Dec. Position | -36° 8' 17.0" |
| 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 |
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| 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. |
