The images and illustration reveal that the Andromeda Galaxy's (M31's) core is composed of a ring of old, red stars and a newly discovered disk of young, blue stars. The disk is trapped within a supermassive black hole's gravitational field. The mass of Andromeda's monster black hole is 140 million times greater than that of our Sun.
The illustration at bottom, right shows the structure of Andromeda's unusual core and is based on Hubble images of the region. The disk of blue stars is nested inside the larger ring of red stars. The tiny black dot within the blue disk is the monster black hole.
Astronomers deduced the structure of Andromeda's core from Hubble images taken over the past decade. The image at upper, right, taken with the Wide Field and Planetary Camera 2, shows that the galaxy appears to have two cores. Normal galaxies only have one core. Astronomers now believe
that Andromeda has one core. The two bright blobs are actually the ring of red stars and the disk of blue stars. In fact, the bright blob on the right has a bluish cast.
The image at left is a view of the entire Andromeda Galaxy. The active core is in the center of the galaxy. Andromeda is 2.5 million light-years from Earth.
Credits
Photo at left: ©2002, R. Gendler, Photo by Robert Gendler;Upper right: NASA, ESA and T. Lauer (NOAO/AURA/NSF);
Lower right illustration: NASA, ESA and A. Feild (STScI)
| About The Object | |
|---|---|
| Object Name | M31, Andromeda Galaxy, NGC 224 |
| Object Description | Spiral Galaxy, Galaxy Core |
| R.A. Position | 00h 42m 44.3s |
| Dec. Position | 41° 16' 9.4" |
| Constellation | Andromeda |
| Distance | About 2.5 million light-years (0.8 Megaparsecs) |
| Dimensions | The WFPC2 image of M31's nucleus is 11.6 arcminutes (150 light-years or 46.5 parsecs) across. |
| About The Data | |
| Data Description | The WFPC2 science data are from the HST proposal : J. Westphal (Caltech), T.R. Lauer (NOAO/AURA/NSF), S. M. FABER UCO/Lick Observatory, W. Baum (Univ. of Washington) The STIS science data are from the HST proposal 8018: R. Green (NOAO/KPNO) and G. Bower (NOAO). The science team includes: R. Bender (Univ. of Sternwarte, Munich; Max Planck Inst., Garching; Univ. of Texas at Austin), J. Kormendy (Univ. of Texas at Austin), G. Bower (CSC/STScI), R. Green (NOAO), J. Thomas (Univ. of Sternwarte, Munich; Max Planck Inst., Garching), A.C. Danks (Bowie, MD), T. Gull (NASA/GSFC), J.B. Hutchings (NRC of Canada), C.L. Joseph (Rutgers Univ.), M.E. Kaiser (JHU), T.R. Lauer (NOAO/AURA/NSF), C.H. Nelson (UNLV), D. Richstone (Univ. of Michigan), D. Weistrop (UNLV), and B. Woodgate (NASA/GSFC). |
| Instrument | 12.5-inch Richey-Chrétien telescope (left), and HST>WFPC2 and HST>STIS (HST data, top right) |
| Exposure Dates | 2002 (left), and June 18-20, 1995, Exposure Time: 3.7 hours (WFPC2) and July 23-24, 1999, Exposure Time: 6.3 hours (STIS) |
| Filters | HST Data WFPC2: F160BW, F300W (U), F555W (V), F814W (I) STIS: G430L, G750M |
| About The Image | |
| 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. |
