Hi My Friends: A VUELO DE UN QUINDE EL BLOG., New results based on the two objects shown here are challenging the
prevailing ideas as to how supermassive black holes grow in the centers
of galaxies. NGC 4342 and NGC 4291, the two galaxies in the study, are
nearby in cosmic terms at distances of 75 million and 85 million light
years respectively. In these composite images, X-rays from NASA's
Chandra X-ray Observatory are colored blue, while infrared data from the
2MASS project are seen in red.
NGC 4342 and NGC 4291:
Black Hole Growth Found to be Out of Synch
Black Hole Growth Found to be Out of Synch
http://chandra.harvard.edu/photo/2012/ngc4342/
- Two black holes are challenging the prevailing idea of how giant black holes grow in the cores of galaxies.
- These black holes are found in the centers of two relatively nearby galaxies: NGC 4342 and NGC 4291.
- New Chandra data suggest that the growth of these black holes is tied to the envelopes of dark matter around the galaxies, not their bulges.
New results based on the two objects shown here are challenging the prevailing ideas as to how supermassive black holes
grow in the centers of galaxies. NGC 4342 and NGC 4291, the two galaxies in the study, are nearby in cosmic terms at distances
of 75 million and 85 million light years respectively. In these
composite images, X-rays from NASA's Chandra X-ray Observatory are
colored blue, while infrared data from the 2MASS project are seen in red.
Astronomers had known from previous observations that these galaxies
host black holes with unusually large masses compared to the mass
contained in the central bulge of stars. To study the dark matter
envelopes contained in each galaxy, Chandra was used to examine their
hot gas content, which was found to be widespread in both objects.
By analyzing the distribution of the hot gas, researchers were able
to test whether the galaxies had "lost weight" through stars being
pulled away during a tidal
encounter with another galaxy. Estimates of the pressure of the hot
gas, which must balance the gravitational pull of all the matter in the
galaxy, showed that massive envelopes of dark matter must exist around
each galaxy. Since this tidal stripping would have severely depleted the
dark matter, which is more loosely tied to the galaxies than the stars,
this process is unlikely to have occurred in either galaxy.
The new results using NGC 4342 and NGC 4291 challenge the long-held
idea that black holes at the centers of galaxies always grow in tandem
with the bulges of stars
that surround them. Rather this study suggests that the two
supermassive black holes and their evolution are tied more closely to
the amount and distribution of dark matter in each galaxy. In this
picture the weights of the black hole and the dark matter envelope in
these two galaxies are "normal" and the galaxies are underweight because
they formed unusually slowly.
| Fast Facts for NGC 4342: | |
| Credit | X-ray: NASA/CXC/SAO/A.Bogdan et al; Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF |
| Scale | 6 arcmin across. |
| Category | Black Holes |
| Coordinates (J2000) | RA 12h 23m 39.02s | Dec +07° 03' 14.17" |
| Constellation | Virgo |
| Observation Dates | 11 Feb 2005 and 17 Feb 2011 |
| Observation Time | 31 hours 15 min (1 day 7 hours 15 min) |
| Obs. IDs | 4687, 12955 |
| Color Code | X-ray (Blue); Infrared (Red) |
| Instrument | ACIS |
| References | Bogdan, A et al. 2012, ApJ (accepted); arXiv:1203.1641 |
| Distance Estimate | About 75 million light years |
| Release Date | June 11, 2012 |
|
||||||||||||||||||||||||||||
Astronomers had known from previous observations that these galaxies
host black holes with unusually large masses compared to the mass
contained in the central bulge of stars. To study the dark matter
envelopes contained in each galaxy, Chandra was used to examine their
hot gas content, which was found to be widespread in both objects.
By analyzing the distribution of the hot gas, researchers were able to test whether the galaxies had "lost weight" through stars being pulled away during a tidal encounter with another galaxy. Estimates of the pressure of the hot gas, which must balance the gravitational pull of all the matter in the galaxy, showed that massive envelopes of dark matter must exist around each galaxy. Since this tidal stripping would have severely depleted the dark matter, which is more loosely tied to the galaxies than the stars, this process is unlikely to have occurred in either galaxy.
The new results using NGC 4342 and NGC 4291 challenge the long-held idea that black holes at the centers of galaxies always grow in tandem with the bulges of stars that surround them. Rather this study suggests that the two supermassive black holes and their evolution are tied more closely to the amount and distribution of dark matter in each galaxy. In this picture the weights of the black hole and the dark matter envelope in these two galaxies are "normal" and the galaxies are underweight because they formed unusually slowly.
Credits: X-ray: NASA/CXC/SAO/A.Bogdan et al; Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF
› Read more/access all images
› Chandra's Flickr photoset
NASABy analyzing the distribution of the hot gas, researchers were able to test whether the galaxies had "lost weight" through stars being pulled away during a tidal encounter with another galaxy. Estimates of the pressure of the hot gas, which must balance the gravitational pull of all the matter in the galaxy, showed that massive envelopes of dark matter must exist around each galaxy. Since this tidal stripping would have severely depleted the dark matter, which is more loosely tied to the galaxies than the stars, this process is unlikely to have occurred in either galaxy.
The new results using NGC 4342 and NGC 4291 challenge the long-held idea that black holes at the centers of galaxies always grow in tandem with the bulges of stars that surround them. Rather this study suggests that the two supermassive black holes and their evolution are tied more closely to the amount and distribution of dark matter in each galaxy. In this picture the weights of the black hole and the dark matter envelope in these two galaxies are "normal" and the galaxies are underweight because they formed unusually slowly.
Credits: X-ray: NASA/CXC/SAO/A.Bogdan et al; Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF
› Read more/access all images
› Chandra's Flickr photoset
Guillermo GOnzalo Sánchez Achutegui
ayabaca@hotmail.com
ayabaca@gmail.com
ayabaca@yahoo.com
Inscríbete en el Foro del blog y participa : A Vuelo De Un Quinde - El Foro!
No hay comentarios:
Publicar un comentario