These Hubble Space Telescope images show elliptical galaxies with dark, wispy dust lanes, the signature of a recent galaxy merger. The dust is the only relic of a smaller galaxy that was consumed by the larger elliptical galaxy.
The "X" in the images marks the location of supernova explosions that are associated with the galaxies. Each supernova may have been gravitationally kicked out of its host galaxy by a pair of central supermassive black holes. When two galaxies merge, so do their supermassive black holes. Astronomers suggest the supernovae were stars that were once part of double-star systems. These systems wandered too close to the binary black holes, which ejected them from their galaxies. Eventually, the stars in each system moved close enough together to trigger a supernova blast.
These outcast supernovae are located at various distances from their home galaxies. SN 2000ds (left) is at least 12,000 light-years from its galaxy, NGC 2768; SN 2005cz (right) is at least 7,000 light-years from its galaxy, NGC 4589. NGC 2768 resides 75 million light-years from Earth, and NGC 4589 is 108 million light-years away.
The supernovae are part of a census of 13 supernovae to determine why they detonated outside the cozy confines of galaxies. The study is based on archived images made by several telescopes, including Hubble.
Both galaxies were observed by Hubble's Advanced Camera for Surveys. The image of NGC 4589 was taken on Nov. 11, 2006, and the image of NGC 2768 on May 31, 2002.
Credits
NASA, ESA, and R. Foley (University of Illinois)| About The Object | |
|---|---|
| Object Name | NGC 2768, and NGC 4589 |
| Object Description | Elliptical galaxies |
| About The Data | |
| Data Description | Data were obtained from the HST proposals PI: H. Ford (JHU) et al., and and PI: S. Smartt (Queen's University of Belfast) et al. |
| Instrument | HST>ACS/WFC |
| Exposure Dates | NGC 2768: May 31, 2002, and January 14, 2003; NGC 4589: November 11, 2006 |
| Filters | F435W (B), F555W (V), and F814W (I) |
| About The Image | |
| Color Info | This image is a composite of separate exposures acquired by the ACS/WFC instrument. Several filters were used to sample various wavelengths. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are: Blue: F435W (B) Green: F555W (V) Red: 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. |
