Tracing Diffuse Starlight in Galaxy Clusters
Two massive galaxy clusters — Abell S1063 (left) and MACS J0416.1-2403 (right) — display a soft blue haze, called intracluster light, embedded among innumerable galaxies. The intracluster light is produced by orphan stars that no longer belong to any single galaxy, having been thrown loose during a violent galaxy interaction, and now drift freely throughout the cluster of galaxies. Astronomers have found that intracluster light closely matches with a map of mass distribution in the cluster's overall gravitational field. This makes the blue "ghost light" a good indicator of how invisible dark matter is distributed in the cluster. Dark matter is a key missing link in our understanding of the structure and evolution of the universe. Abell S1063 and MACS J0416.1-2403 were the strongest examples of intracluster light providing a much better match to the cluster's mass map than X-ray light, which has been used in the past to trace dark matter.
Credits
NASA, ESA, and M. Montes (University of New South Wales)| About The Object | |
|---|---|
| Object Name | Abell S1063 and MACS J0416.1-2403 |
| Object Description | Galaxy Clusters |
| About The Data | |
| Data Description | Abell S1063 and MACS J0416 are part of the Frontier Fields Program. These data are from the HST proposals (PI: M. Postman, STScI), 13459 (PI: T. Treu, UCLA), (PI: J. Lotz, STScI), and (PI: B. Siana, UC Riverside). |
| Instrument | ACS/WFC, WFC3/IR |
| Exposure Dates | December 2005 - May 2016 |
| Filters | ACS/WFC: F435W, F606W, F814W; WFC3/IR: F105W, F125W, F140W, and F160W |
| About The Image | |
| Color Info | These images are composites of separate exposures acquired by the WFC3/IR and ACS/WFC instruments. 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: ACS/WFC F435W (B) + F606W (R) Green: ACS/WFC F814W (I) + WFC3/IR F105W (Y) Red: WFC3/IR F125W (J) + F140W (JH) + F160W (H) |
| 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. |
