VLA Gives New Insight Into Galaxy Cluster's Spectacular "Mini-Halo"
Astronomers using the National Science Foundation's Karl G. Jansky Very Large Array (VLA) have discovered new details that are helping them decipher the mystery of how giant radio-emitting structures are formed at the center of a cluster of galaxies. The scientists studied a cluster of thousands of galaxies more than 250 million light-years from Earth, named the Perseus Cluster after the constellation in which it appears. Embedded within the center, the Perseus Cluster hosts a pool of superfast particles that emit radio waves, creating a radio structure known as a "mini-halo." Mini-haloes have been found in about 30 galaxy clusters, but the halo in the Perseus Cluster is the largest known, about 1.3 million light-years in diameter, or 10 times the size of our Milky Way Galaxy. Read more
Perseus Cluster: Scientists Find Giant Wave Rolling through the Perseus Galaxy Cluster
Combining data from NASA's Chandra X-ray Observatory with radio observations and computer simulations, scientists have found a vast wave of hot gas in the Perseus galaxy cluster. Spanning some 200,000 light years, the wave is about twice the size of the Milky Way galaxy. Researchers think the wave formed billions of years ago after a small galaxy cluster grazed Perseus and caused its vast supply of gas to slosh around in an enormous volume of space. Read more
Perseus Cluster and Virgo Cluster: NASA's Chandra Observatory Identifies Impact of Cosmic Chaos on Star Birth
These two Chandra images of galaxy clusters - known as Perseus and Virgo - have provided direct evidence that turbulence is helping to prevent stars from forming. These new results could answer a long-standing question about how these galaxy clusters keep their enormous reservoirs of hot gas from cooling down to form stars, as discussed in our latest press release Read more
Title: Herschel observations of extended atomic gas in the core of the Perseus cluster Authors: Rupal Mittal, J. B. Raymond Oonk, Gary J. Ferland, Alastair C. Edge, Christopher P. O'Dea, Stefi A. Baum, John T. Whelan, Roderick M. Johnstone, Francoise Combes, Philippe Salome, Andy C. Fabian, Grant R. Tremblay, Megan Donahue, Helen Russell
We present Herschel observations of the core of the Perseus cluster of galaxies. The brightest cluster galaxy, NGC 1275, is surrounded by a network of filaments previously imaged extensively in H{\alpha} and CO. In this work, we report detections of FIR lines with Herschel. All but one of the lines are spatially extended, with the [CII] line emission extending up to 25 kpc from the core. There is spatial and kinematical correlation among [CII], H{\alpha} and CO, which gives us confidence to model the different components of the gas with a common heating model. With the help of FIR continuum Herschel measurements, together with a suite of coeval radio, submm and infrared data, we performed a SED fitting of NGC 1275 using a model that contains contributions from dust emission as well as synchrotron AGN emission. The data indicate a low dust emissivity index, beta ~ 1, a total dust mass close to 10^7 solar mass, a cold dust component with temperature 38 ± 2 K and a warm dust component with temperature of 116 ± 9 K. The FIR-derived star formation rate (SFR) is 24 ± 1 solar mass per yr, in close agreement with the FUV-derived SFR. We investigated in detail the source of the Herschel FIR and H{\alpha} emissions emerging from a core region 4 kpc in radius. Based on simulations conducted using the radiative transfer code, CLOUDY, a heating model comprising old and young stellar populations is sufficient to explain these observations. We have also detected [CII] in three well-studied regions of the filaments. We find a [OI]/[CII] ratio about 1 dex smaller than predicted by the otherwise functional Ferland (2009) model. The line ratio suggests that the lines are optically thick, as is typical of galactic PDRs, and implies that there is a large reservoir of cold atomic gas.
Suzaku Shows Clearest Picture Yet Of Perseus Galaxy Cluster
X-ray observations made by the Suzaku observatory provide the clearest picture to date of the size, mass and chemical content of a nearby cluster of galaxies. The study also provides the first direct evidence that million-degree gas clouds are tightly gathered in the cluster's outskirts. Suzaku is sponsored by the Japan Aerospace Exploration Agency (JAXA) with contributions from NASA and participation by the international scientific community. The findings will appear in the March 25 issue of the journal Science. Galaxy clusters are millions of light-years across, and most of their normal matter comes in the form of hot X-ray-emitting gas that fills the space between the galaxies. Read more