Images by Date
Images by Category
Solar System
Stars
White Dwarfs
Supernovas
Neutron Stars
Black Holes
Milky Way Galaxy
Normal Galaxies
Quasars
Galaxy Clusters
Cosmology/Deep Field
Miscellaneous
Images by Interest
Space Scoop for Kids
Multiwavelength
Sky Map
Constellations
3D Wall
Photo Blog
Top Rated Images
Image Handouts
Desktops
High Res Prints
Fits Files
Image Tutorials
Photo Album Tutorial
False Color
Cosmic Distance
Look-Back Time
Scale & Distance
Angular Measurement
Images & Processing
AVM/Metadata
Getting Hard Copies
Image Use Policy
Web Shortcuts
Chandra Blog
RSS Feed
Chandra Mobile
Chronicle
Email Newsletter
News & Noteworthy
Image Use Policy
Questions & Answers
Glossary of Terms
Download Guide
Get Adobe Reader
More Information
Quasars & Active Galaxies
X-ray Astronomy Field Guide
Quasars & Active Galaxies
Questions and Answers
Quasars & Active Galaxies
Chandra Images
Quasars & Active Galaxies
Related Podcasts
Tour of RX J1131-1231
Download Image

More Information
Handout
Handout: html | pdf

More Images
Chandra X-ray Image of
3C442A
(Credit: NASA/CXC/Univ. of Bristol/Worrall et al.)

Animation & Video


Related Images
M87
M87
(05 Oct 06)
Centaurus A Arcs
Centaurus A Arcs
(07 Aug 02)
Cygnus A
Cygnus A
(06 Nov 00)
3C442A:
Galaxy Collision Causes Role Reversal



Credit: X-ray: NASA/CXC/Univ. of Bristol/Worrall et al.; Radio: NRAO/AUI/NSF

Astronomers think that there are enormous black holes at the centers of most, if not all, galaxies. These black holes, which can be millions or even billions of times more massive than the Sun, can greatly affect the galaxy and the environments around them. One way such black holes shape their surroundings is by generating powerful jets of high-energy particles. The jets, which are bright in radio waves, have been seen to push around the hot gas that envelops the galaxy. When this happens, astronomers can detect huge cavities and powerful shock fronts in the hot, X-ray emitting gas.

However, the opposite scenario is apparently unfolding in the galaxy known as 3C442A. X-ray data from NASA's Chandra X-ray Observatory and radio observations from the NSF's Very Large Array show that the hot gas (blue) in the middle of 3C442A is pushing apart the radio-bright gas (orange). The inner sections of the radio structure are sharp and concave, which is consistent with the idea that the X-ray bright gas is sweeping the radio-emitting gas aside. This is the first convincing evidence for such a role reversal.

A team of scientists, led by Diana Worrall of University of Bristol, UK, has studied this system and determined why the dynamics in 3C442A seem to be topsy-turvy. First, there are two galaxies near the middle of 3C442A which are in the process of merging. These two galaxies are on their second pass toward a collision, having already experienced a close encounter. The energy generated from this impending merger is heating the combined atmospheres from these two galaxies, causing them to shine brightly in X-rays and expand.

The researchers determined that the jets that had produced the lobes of radio-emitting gas are no longer active. The jets may have ceased at the time of, and possibly as a result of, the galaxy collision. Since the radio-emitting gas no longer has a power source, it is then at the mercy of the expanding hot gas and has been pushed aside.

Fast Facts for 3C442A:
Credit 
Scale  Image is 22 by 13 arcmin
Category  Quasars & Active Galaxies
Coordinates (J2000)  RA 22h 14m 47.00s | Dec +13 46' 16.00"
Constellation  Pegasus
Observation Dates  4 pointings between July 2005 - January, 2006
Observation Time  28 hours
Obs. IDs  5635, 6353, 6359, 6392
Color Code  X-ray (blue); Radio (orange)
Instrument  ACIS
References The Effect of a Chandra-measured Merger-related Gas Component on the Lobes of a Dead Radio Galaxy. Worral, D.M., Birkinshaw, M., Kraft, R.P., Hardcastle, M.J., 2007, ApJ, 685, 79
Distance Estimate  About 390 million light years
Release Date  March 29, 2007