Beginning in 2004, the Hubble Space Telescope has observed a spot in the sky known as the Hubble Ultra Deep Field (HUDF) many times. The extremely deep and detailed cumulative exposure reveals some of the faintest objects ever detected, some of which turn out also to be among the most distant galaxies known. Studying this set of images has allowed astronomers to understand the scale, structure, and development of the universe much more completely and precisely.
The first set of deep HUDF images were made with Hubble's Advanced Camera for Surveys (ACS) in 2004. The addition of the Wide Field Camera 3 to Hubble's complement of instruments in 2009 extended the reach of the HUDF beyond visible light, farther into the infrared, to reveal even more distant galaxies. Due to the expansion of the universe, distant objects appear redder because they are moving away from us faster than closer objects. The most distant objects are red-shifted so much that they cannot be detected at all in visible light, but appear only at infrared wavelengths.
Observing the same field repeatedly adds exposure to reveal fainter objects but the longer time span of data also increases the chance of detecting a supernova. Supernovae are extremely violent explosions of single stars resulting in a flash of light bright enough to outshine an entire galaxy of hundreds of billion stars. Although a supernova is relatively rare in any one galaxy, so many galaxies appear in the HUDF that several supernovae have been seen in this small part of the sky in the time that Hubble has been observing. A particular type of Supernova, known as Type Ia is especially important because their intrinsic brightnesses are all nearly equal. Since a more distant source of light will appear dimmer than a nearer object of the same brightness, the observed brightness of a Type Ia supernova tells us its distance.
Observations of many supernovae have allowed astronomers to refine the understanding of the universe's structure. Recently, these studies have revealed the existence of a mysterious force causing the universe to expand ever faster, a phenomenon now known as "dark energy."
This image combines numerous exposures made in visible and infrared light with Hubble's Advanced Camera for Surveys (ACS) and near infrared with the Wide Field Camera 3 infrared channel (WFC3/IR). ACS images from blue and yellow-green filters are shown in blue, ACS red and near infrared filters in green, and WFC3 infrared light in red.
Credits
NASA, ESA, A. Riess (JHU and STScI), S. Rodney (JHU), and the Hubble Heritage Team (STScI/AURA)| About The Object | |
|---|---|
| Object Name | Hubble Ultra Deep Field, HUDF |
| Object Description | Deep survey |
| R.A. Position | 03h 32m 38.01s |
| Dec. Position | -27° 46' 39.08" |
| Constellation | Fornax |
| 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. |
