Images by Date
Images by Category
Solar System
White Dwarfs
Neutron Stars
Black Holes
Milky Way Galaxy
Normal Galaxies
Galaxy Clusters
Cosmology/Deep Field
Images by Interest
Space Scoop for Kids
Sky Map
Photo Blog
Top Rated Images
Image Handouts
Fits Files
Image Tutorials
Photo Album Tutorial
False Color
Cosmic Distance
Look-Back Time
Scale & Distance
Angular Measurement
Images & Processing
Image Use Policy
Web Shortcuts
Chandra Blog
RSS Feed
Email Newsletter
News & Noteworthy
Image Use Policy
Questions & Answers
Glossary of Terms
Download Guide
Get Adobe Reader
NGC 3115: Chandra Images Gas Flowing Toward Black Hole
NGC 3115
NGC 3115

  • The galaxy NGC 3115 contains a supermassive black hole at its center.

  • New Chandra data has been used to clearly image hot gas as it falls toward this giant black hole.

  • This is the first time that clear evidence for such a flow has been observed in any black hole.

  • Astronomers observed a critical threshold known as the "Bondi radius" using Chandra.

The galaxy NGC 3115 is shown here in a composite image of data from NASA's Chandra X-ray Observatory and the European Southern Observatory's Very Large Telescope (VLT). Using the Chandra image, the flow of hot gas toward the supermassive black hole in the center of this galaxy has been imaged. This is the first time that clear evidence for such a flow has been observed in any black hole.

The Chandra data are shown in blue and the optical data from the VLT are colored gold. The point sources in the X-ray image are mostly binary stars containing gas that is being pulled from a star to a stellar-mass black hole or a neutron star. The inset features the central portion of the Chandra image, with the black hole located in the middle. No point source is seen at the position of the black hole, but instead a plateau of X-ray emission coming from both hot gas and the combined X-ray emission from unresolved binary stars is found.

To detect the black hole's effects, astronomers subtracted the X-ray signal from binary stars from that of the hot gas in the galaxy's center. Then, by studying the hot gas at different distances from the black hole, astronomers observed a critical threshold: where the motion of gas first becomes dominated by the supermassive black hole's gravity and falls inwards. The distance from the black hole where this occurs is known as the "Bondi radius."

As gas flows toward a black hole it becomes squeezed, making it hotter and brighter, a signature now confirmed by the X-ray observations. The researchers found the rise in gas temperature begins at about 700 light years from the black hole, giving the location of the Bondi radius. This suggests that the black hole in the center of NGC 3115 has a mass of about two billion times that of the Sun, supporting previous results from optical observations. This would make NGC 3115 the nearest billion-solar-mass black hole to Earth.

NGC 3115 is located about 32 million light years from Earth and is classified as a so-called lenticular galaxy because it contains a disk and a central bulge of stars, but without a detectable spiral pattern.

Fast Facts for NGC 3115:
Credit  X-ray: NASA/CXC/Univ. of Alabama/K.Wong et al, Optical: ESO/VLT
Release Date  July 27, 2011
Scale  Full image: 7.5 arcmin across (about 70,000 light years) | Inset image: 27 arcsec across (about 4,150 light years)
Category  Black Holes, Normal Galaxies & Starburst Galaxies
Coordinates (J2000)  RA 10h 05m 13.80s | Dec -07° 43´ 09.00"
Constellation  Sextans
Observation Date  3 pointings between June 14, 2001 and Jan 29, 2011
Observation Time  43 hours 6 min (1 day 19 hours 6 min)
Obs. ID  2040, 11268, 12095
Instrument  ACIS
References Wong, K., et al, 2011, ApJ 736L:23W, arXiv:1106.3069
Color Code  X-ray (Blue); Optical (Gold)
Distance Estimate  About 32 million light years
distance arrow
Visitor Comments (6)

There are NO Black Holes, only High plasma focus Plasmoids .

Posted by bob on Wednesday, 06.3.15 @ 16:09pm

Black holes are always interesting but this one is really special and I really liked the part of Bondi-Radius so congratulations for your work Chandra.

Posted by NASAFan on Saturday, 06.28.14 @ 06:38am

Superb picture showing the details of NGC 3115. Who should I ask if I would like to use this picture on another website?
Thank you
Virdina Ahmet

Posted by Virdina on Tuesday, 08.30.11 @ 17:51pm

Unbelievable photo.

Posted by Joseph on Saturday, 08.27.11 @ 03:49am

Extremely Interesting

Posted by Ted Pringle on Thursday, 07.28.11 @ 17:20pm

Congratulations, and well done.

Posted by Mark Ballington on Thursday, 07.28.11 @ 10:36am

Rate This Image

Rating: 3.8/5
(515 votes cast)
Download & Share

More Information
Press Room: NGC 3115
Blog: NGC 3115

More Images
X-ray Image of
NGC 3115
Jpg, Tif

More Images
Animation & Video
Tour of NGC 3115

More Animations
Related Images
NGC 4374
NGC 4374
(10 Jan 08)

M33 X-7
M33 X-7
(17 Oct 07)

NGC 4696
NGC 4696
(24 Apr 06)

SDSSp J1306
SDSSp J1306
(22 Nov 04)

Related Information
Related Podcast
Top Rated Images
Chandra Releases 3D Instagram Experiences

Timelapses: Crab Nebula and Cassiopeia A

Brightest Cluster Galaxies