Omega Centauri (cropped)

 Omega Centauri (cropped)

An international team of astronomers has used more than 500 images from NASA's Hubble Space Telescope – spanning two decades of observations – to detect seven fast-moving stars in the innermost region of Omega Centauri, the largest and brightest globular cluster in the sky. These stars provide compelling new evidence for the presence of an intermediate-mass black hole (IMBH).

Omega Centauri is visible from Earth with the naked eye and is one of the favorite celestial objects for stargazers in the southern hemisphere. Although the cluster is 17,700 light-years away, lying just above the plane of the Milky Way, it appears almost as large as the full Moon when seen from a dark rural area. The exact classification of Omega Centauri has evolved through time, as our ability to study it has improved. It was first listed in Ptolemy's catalog nearly 2,000 years ago as a single star. Edmond Halley reported it as a nebula in 1677. In the 1830s the English astronomer John Herschel was the first to recognize it as a globular cluster. Omega Centauri consists of roughly 10 million stars that are gravitationally bound. The cluster is about 10 times as massive as other big globular clusters – almost as massive as a small galaxy.

This image shows the central region of the Omega Centauri globular cluster, where the IMBH candidate was found.

About The Object
Object Name Omega Centauri, NGC 5139
Object Description Globular cluster
R.A. Position 13:26:49.56
Dec. Position -47:29:32.66
Constellation Centaurus
Distance 17,700  light-years
Dimensions Image is about 9.2 arcminutes across (47 light-years) 
About The Data
Data Description The HST observations include those from programs (A. Cool), (J. Anderson), , (A. Sarajedini), (J. Lee), (L. Smith), (J. Anderson), (V. Kozhurina-Platais), (N. Hathi), (A. Bellini), (M. Chiaberge), (Y. Cohen), (N. Hathi), (N. Hathi), (J. Quijano), (C. Kochnek), (L. Petro), (E. Sabbi), (V. Kozhurina-Platais), (A. Renzini), (K. Long), (A. Riess), (V. Kozhurina-Platais), (J. MacKenty), (V. Kozhurina-Platais), (V. Kozhurina-Platais), (V. Kozhurina-Platais), (V. Kozhurina-Platais), (V. Kozhurina-Platais), (T. Brown), (V. Kozhurina-Platais), (V. Kozhurina-Platais), (V. Kozhurina-Platais), (V. Kozhurina-Platais), (A. Bellini), (M. Reinhart), (R. Bohlin), (J. Anderson), (V. Kozhurina-Platais), (A. Seth), and (C. Martlin). This dataset contains HST observations of the globular cluster Omega Centauri out to its half-light radius. The data were selected to contain all available observations with filters suitable for high-precision astrometry (ACS/WFC: F435W, F475W, F555W, F606W, F625W, F775W, F814W; WFC3/UVIS: F336W, F390W, F438W, F555W, F606W, F775W, F814W). In addition, the filters ACS/WFC F658N and WFC3/UVIS F275W were added for photometric purposes as they also cover almost the entire half-light radius. The data were taken in the time spanning from June 2002 to March 2023. They have been collectively compiled .
Instrument WFC3/UVIS, ACS/WFC
Exposure Dates 27 June 2002- 23 Feb 2024 
 
Filters F275W, F336W, F438W, F606W, F625W, F658N, F814W 
About The Image
Color Info These images are a composite of separate exposures acquired by the WFC3/UVIS instrument on the Hubble Space Telescope. Several filters were used to sample various 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= F275W + F336W + F438W, Green= F606W + F625W, Red= F658N + F814W
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
  • Proposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
  • Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.
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.