This is a Hubble Space Telescope image of the most massive cluster of galaxies ever seen to exist when the universe was just half of its current age of 13.8 billion years. The cluster, catalogued as ACT-CL J0102-4915, contains several hundred galaxies swarming around under a collective gravitational pull. The total mass of the cluster, as refined in new Hubble measurements, is estimated to weigh as much as 3 million billion stars like our Sun (about 3,000 times the mass of our own Milky Way galaxy) – though most of the mass is hidden away as dark matter. The location of the dark matter is mapped out in the blue overlay. Because dark matter doesn't emit any radiation, Hubble astronomers instead precisely measure how its gravity warps the images of far background galaxies like a funhouse mirror. This allowed them to come up with a mass estimate for the cluster. The cluster was nicknamed El Gordo (Spanish for "the fat one") in 2012 when X-ray observations (shown in pink) and kinematic studies first suggested it was unusually massive for the time in the early universe when it existed. The Hubble data have confirmed that the cluster is undergoing a violent merger between two smaller clusters.
Credits
NASA, ESA, J. Jee (University of California, Davis), J. Hughes (Rutgers University), F. Menanteau (Rutgers University and University of Illinois, Urbana-Champaign), C. Sifon (Leiden Observatory), R. Mandelbum (Carnegie Mellon University), L. Barrientos (Universidad Catolica de Chile), and K. Ng (University of California, Davis)| About The Object | |
|---|---|
| Object Name | El Gordo, ACT-CL J0102-4915 |
| Object Description | Galaxy Cluster |
| R.A. Position | 01h 2m 52.99s |
| Dec. Position | -49° 15' 19.01" |
| Constellation | Phoenix |
| Distance | 9.7 billion light-years (3 billion parsecs) |
| About The Data | |
| Data Description | The Hubble data are from proposal : J. Hughes (Rutgers University), F. Menanteau (Rutgers University/University of Illinois, Urbana-Champaign), L. Infante and L.F. Barrientos (Ponticia Universidad Catolica de Chile), and R. Mandelbaum (Carnegie Mellon University), and archival data from proposal : F. High (University of Chicago) et al. |
| Instrument | HST>ACS/WFC, and Chandra X-ray |
| Exposure Dates | September - October, 2012 |
| Filters | ACS/WFC: F606W ((V), F625W (r), F775W (i), F814W (I), and F850LP (z); Chandra X-ray |
| About The Image | |
| Color Info | This composite image includes exposures acquired by the ACS instruments on the Hubble Space Telescope. Several filters were used to sample broad wavelength ranges. 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: F625W (r) Green: F775W (i) Red: F850LP (z) Cyan: Derived Mass Pink: Chandra X-ray |
| 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. |
