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
Elliptical Galaxies: Chandra Helps Explain "Red and Dead Galaxies"

  • A new study looks at why some giant elliptical galaxies have such low levels of star formation despite reservoirs of fuel to make them.

  • Astronomers used Chandra to determine the role that supermassive black holes play in this dearth of stellar birth.

  • Outbursts from the supermassive black hole may be preventing the gas from cooling enough to allow stars to form.

  • These four galaxies are part of a sample of eight in the study.

NASA's Chandra X-ray Observatory has shed new light on the mystery of why giant elliptical galaxies have few, if any, young stars. This new evidence highlights the important role that supermassive black holes play in the evolution of their host galaxies.

Because star-forming activity in many giant elliptical galaxies has shut down to very low levels, these galaxies mostly house long-lived stars with low masses and red optical colors. Astronomers have therefore called these galaxies "red and dead".

Previously it was thought that these red and dead galaxies do not contain large amounts of cold gas - the fuel for star formation - helping to explain the lack of young stars. However, astronomers have used ESA's Herschel Space Observatory to find surprisingly large amounts of cold gas in some giant elliptical galaxies. In a sample of eight galaxies, six contain large reservoirs of cold gas. This is the first time that astronomers have seen large quantities of cold gas in giant elliptical galaxies that are not located at the center of a massive galaxy cluster.

With lots of cold gas, astronomers would expect many stars to be forming in these galaxies, contrary to what is observed. To try to understand this inconsistency, astronomers studied the galaxies at other wavelengths, including X-rays and radio waves. The Chandra observations map the temperature and density of hot gas in these galaxies. For the six galaxies containing abundant cold gas, including NGC 4636 and NGC 5044 shown here, the X-ray data provide evidence that the hot gas is cooling, providing a source for the cold gas observed with Herschel. However, the cooling process stops before the cold gas condenses to form stars. What prevents the stars from forming?

A strong clue comes from the Chandra images. The hot gas in the center of the six galaxies containing cold gas appears to be much more disturbed than in the cold gas-free systems. This is a sign that material has been ejected from regions close to the central black hole. These outbursts are possibly driven, in part, by clumpy, cold gas that has been pulled onto the black hole. The outbursts dump most of their energy into the center of the galaxy, where the cold gas is located, preventing the cold gas from cooling sufficiently to form stars.

The other galaxies in the sample, NGC 1399 and NGC 4472, are also forming few if any stars, but they have a very different appearance. No cold gas was detected in these galaxies, and the hot gas in their central regions is much smoother. Additionally, they have powerful jets of highly energetic particles, as shown in radio images from the National Science Foundation's Karl G. Jansky Very Large Array. These jets are likely driven by hot gas falling towards the central supermassive black holes. By pushing against the hot gas, the jets create enormous cavities that are observed in the Chandra images, and they may heat the hot, X-ray emitting gas, preventing it from cooling and forming cold gas and stars. The centers of NGC 1399 and NGC 4472 look smoother in X-rays than the other galaxies, likely because their more powerful jets produce cavities further away from the center, where the X-ray emission is fainter, leaving their bright cores undisturbed.

A paper describing these results was published in the February 25, 2014 issue of the Monthly Notices of the Royal Astronomical Society and is available online. The first author is Norbert Werner from Stanford University in California.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Mass., controls Chandra's science and flight operations.

Fast Facts for NGC 1399:
Credit  X-ray: NASA/CXC/Stanford Univ/N.Werner et al.
Release Date  May 30, 2014
Scale  Image is 6.5 arcmin across. (about 130,000 light years)
Category  Normal Galaxies & Starburst Galaxies
Coordinates (J2000)  RA 03h 38m 29.08s | Dec -35 27' 02.67"
Constellation  Fornax
Observation Dates  3 pointings between 18 Jan 2000 and 08 Jun 2008
Observation Time  40 hours 32 min (1 day 16 hours 32 min)
Obs. IDs  319, 4172, 9530
Instrument  ACIS
References Werner, N. et al, 2014, MNRAS 439, 2291-2306; arXiv:1310.5450
Color Code  X-ray (Blue)
X-ray
Distance Estimate  About 65 million light years
Fast Facts for NGC 4472:
Credit  X-ray: NASA/CXC/Stanford Univ/N.Werner et al.
Release Date  May 30, 2014
Scale  Image is 6.5 arcmin across. (about 100,000 light years)
Category  Normal Galaxies & Starburst Galaxies
Coordinates (J2000)  RA 12h 29m 46.90s | Dec +08 00' 13.00
Constellation  Virgo
Observation Dates  12 Jun 2000
Observation Time  11 hours 6 min
Obs. IDs  321
Instrument  ACIS
References Werner, N. et al, 2014, MNRAS 439, 2291-2306; arXiv:1310.5450
Color Code  X-ray (Blue)
X-ray
Distance Estimate  About 55 million light years
Fast Facts for NGC 4636:
Credit  X-ray: NASA/CXC/Stanford Univ/N.Werner et al.
Release Date  May 30, 2014
Scale  Image is 6.5 arcmin across. (about 95,000 light years)
Category  Normal Galaxies & Starburst Galaxies
Coordinates (J2000)  RA 12h 42m 49.87s | Dec +02 41' 16.01"
Constellation  Virgo
Observation Dates  3 pointings between 26 Jan 2000 and 15 Mar 2003
Observation Time  55 hours 57 min (2 days 7 hours 57 min)
Obs. IDs  323, 3926, 4415
Instrument  ACIS
References Werner, N. et al, 2014, MNRAS 439, 2291-2306; arXiv:1310.5450
Color Code  X-ray (Blue)
X-ray
Distance Estimate  About 50 million light years
Fast Facts for NGC 5044:
Credit  X-ray: NASA/CXC/Stanford Univ/N.Werner et al.
Release Date  May 30, 2014
Scale  Image is 6.5 arcmin across. (about 190,000 light years)
Category  Normal Galaxies & Starburst Galaxies
Coordinates (J2000)  RA 13h 15m 23.97s | Dec -16 23' 08.00"
Constellation  Virgo
Observation Dates  2 pointings on 19 Mar 2000 and 07 Mar 2008
Observation Time  28 hours 39 min (1 day 4 hours 39 min)
Obs. IDs  798, 9399
Instrument  ACIS
References Werner, N. et al, 2014, MNRAS 439, 2291-2306; arXiv:1310.5450
Color Code  X-ray (Blue)
X-ray
Distance Estimate  About 102 million light years
Visitor Comments (1)

Could the outer limits of the universe
be red dead, instead of inflating?
-according to the red shift theory
manuel Olisipolis

Posted by manuel gomes on Saturday, 06.7.14 @ 20:38pm


Leave Your Comment

Name:

Email:

Comments:


 
 

Rules

Rate This Image

Rating: 2.8/5
(135 votes cast)
Download & Share

More Information
More Images
X-ray Image of NGC 1399
Jpg, Tif
click for larger image

More Images
More Releases
NGC 5044
NGC 5044
(10 Jan 06)

Related Images
NGC 1399
NGC 1399
(04 Jan 10)
NGC 4472
NGC 4472
(03 Jan 07)
NGC 4636
NGC 4636
(19 Dec 01)

Related Information
Related Podcast
Top Rated Images
WASP-18

M82X-2

Chandra Archive Collection




FaceBookTwitterYouTubeFlickr