Radio halo detected in the galaxy cluster PSZ2 G099.86+58.45

Radio halo detected in the galaxy cluster PSZ2 G099.86+58.45
CFHTLenS g, r and i band composite images of PSZ2G099 with overlaid the LOFAR 144 MHz high resolution (8.300 × 4.300 ) contours (white), the XMM-Newton contours (yellow) and light density contours of the cluster member galaxies (red-dashed). Credit: Cassano et al., 2019.

Using the LOw Frequency ARray (LOFAR), astronomers have probed PSZ2 G099.86+58.45, one of the densest cluster of galaxies known to date. The study revealed the presence of a radio halo in this cluster, making it one of the most distant such features ever discovered. The finding is detailed in a paper published July 24 on arXiv.org.

Radio halos are enormous regions of diffuse radio , usually found at the centers of galaxy clusters. However, diffuse emissions generally have very low surface brightness, particularly at GHz frequencies, what makes them hard to detect. Their brightness increases at , unveiling the presence of these regions.

With the capability of obtaining deep, , high-fidelity and low-frequency radio images, LOFAR is an excellent tool to study radio halos at low frequencies with unprecedented detail and sensitivity. So a group of astronomers led by Rossella Cassano of Institute for Radio Astronomy of Bologna, Italy, employed LOFAR for the observations of the galaxy PSZ2 G099.86+58.45.

At a redshift of approximately 0.62, PSZ2 G099.86+58.45 (PSZ2G099 for short) is a massive and hot galaxy cluster of about 684 trillion solar masses. Observations have shown that the cluster resides in a high-density environment, about six times denser than the average Lambda cold dark matter (ΛCDM) model prediction at this redshift.

Cassano's team investigated PSZ2G099 with LOFAR as part of the LoTSS (LOFAR Two-meter Sky Survey) program. They also conducted follow-up observations of the cluster using the Karl G. Jansky Very Large Array (JVLA). All in all, the observational campaign resulted in the detection of a radio halo in this object.

"In this letter, we report the discovery of a radio halo in the high-redshift galaxy cluster PSZ2 G099.86+58.45 (z = 0.616) with the LOw Frequency ARray (LOFAR) at 120-168 MHz," the astronomers wrote in the paper.

In particular, LOFAR observations at medium resolution revealed extended diffuse emission at the center of PSZ2G099, with dimensions measured at around 3.9 by 1.95 light years. As expected, this emission is very faint at higher frequencies and therefore was barely detected by JVLA.

The astronomers added that the morphology of the observed radio emission resembles that of the X-ray emission as seen on images provided by ESA's XMM-Newton spacecraft.

Taking into account the emission's extension, morphology, and location in the cluster, the researchers classified it as a radio halo. Moreover, the cluster's redshift places it among the most distant radio halos discovered so far, and the furthest away detected by LOFAR.

In concluding remarks, the authors of the paper report that the study shows LOFAR's potential as a unique system to discover radio halos at high redshift. Given that the fraction of clusters with at high redshift and their luminosity depend on the , the scientists hope that LOFAR statistical studies of such halos could deliver essential information on the origin of magnetic fields in galaxy clusters.


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More information: LOFAR discovery of a radio halo in the high-redshift galaxy cluster PSZ2 G099.86+58.45, arXiv:1907.10304 [astro-ph.GA] arxiv.org/abs/1907.10304

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Citation: Radio halo detected in the galaxy cluster PSZ2 G099.86+58.45 (2019, July 31) retrieved 21 September 2019 from https://phys.org/news/2019-07-radio-halo-galaxy-cluster-psz2.html
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Jul 31, 2019
That is an enormous electric current in which that galaxy cluster resides.

Jul 31, 2019
That is an enormous electric current in which that galaxy cluster resides.

I thought radio wave generation due to electricity was from accelerating charge carriers.......

Jul 31, 2019
@cantthink69 doesn't know how big a light year is compared to a galaxy cluster. Cranks can't count. Next there'll be a magic light bulb at the center of the 3 million light year wide cluster causing the 2 light year spot in the middle, according to this loon.

Jul 31, 2019
That is an enormous electric current in which that galaxy cluster resides.


He doesn't even know simple EE circuits and claims plasma is magic.

Jul 31, 2019
That is an enormous electric current in which that galaxy cluster resides.

I thought radio wave generation due to electricity was from accelerating charge carriers.......

Yep, as it states in the abstract;
"Radio halos are currently explained as synchrotron radiation from relativistic electrons that are re-accelerated in the intra-cluster medium..."

Jul 31, 2019
That is an enormous electric current in which that galaxy cluster resides.

I thought radio wave generation due to electricity was from accelerating charge carriers.......

Yep, as it states in the abstract;
"Radio halos are currently explained as synchrotron radiation from relativistic electrons that are re-accelerated in the intra-cluster medium..."

You have figured out how to make an electric outer-space venturi?

Jul 31, 2019
In plasma it is called the Bennett pinch, discovered way back in the 1930's. It's how Birkeland currents are constrained in astrophysical plasmas.

Jul 31, 2019
You aren't aware of the pinch effect?

Jul 31, 2019
In plasma it is called the Bennett pinch, discovered way back in the 1930's. It's how Birkeland currents are constrained in astrophysical plasmas.

A 4ly by 2ly pinch, eh? impressive.

Jul 31, 2019
Here is some math assuming we are working in 2D, since that is what the article used:
Solar System radius ~39.5AU
1 ly ~63270AU
Solar System area ~4900AU^2
1 ly^2 ~4,000,000,000 AU^2
==> ~817,000 Solar Systems / ly^2
==> ~817,000*8 = ~6,500,000 Solar Systems
==> ~6.5 million solar systems fit inside this one single Bennett pinch. I'm even more impressed now.

Jul 31, 2019
There are a lot of cosmic structures - cavities with tenuous, high temperature gas. The nomenclature of these cavities is not finally established yet, but in general there are cavities with a characteristic size of 10 pc – bubbles, about 100 pc – superbubbles, and extended up to 1 kpc or more – supershells. There are a lot of global outflows in our and other star-forming galaxies that percolate galactic disk and are streaming away in galactic halo. These are so called chimneys, fountains, winds and high velocity clouds. All of these structures have an enigmatic nature. In this paper we offer the mechanism which explains their nature in the uniform manner that is based on our original elaston model of the space. https://www.acade...nd_Winds

Jul 31, 2019
Here is some math assuming we are working in 2D, since that is what the article used:
Solar System radius ~39.5AU
1 ly ~63270AU
Solar System area ~4900AU^2
1 ly^2 ~4,000,000,000 AU^2
==> ~817,000 Solar Systems / ly^2
==> ~817,000*8 = ~6,500,000 Solar Systems
==> ~6.5 million solar systems fit inside this one single Bennett pinch. I'm even more impressed now.

From the abstract;
"The diffuse emission extends over ∼ 1 Mpc and has a morphology similar to that of the X-ray emission as revealed by XMM-Newton data."
1 Mpc is closer to 3 million lys, your jaw should be on the floor.

Jul 31, 2019
cant, the word "currently"
ys not currently synonymous
with electric-currents

Aug 01, 2019
cant, the word "currently"
ys not currently synonymous
with electric-currents
LOL

Aug 01, 2019

From the abstract;
"The diffuse emission extends over ∼ 1 Mpc and has a morphology similar to that of the X-ray emission as revealed by XMM-Newton data."
1 Mpc is closer to 3 million lys, your jaw should be on the floor.


Oh good. I'm glad to see you still don't realize how outlandish your thought train is. Pretty neat how there is a pinch out there that is millions of light years across. How can you even for a single second believe the garbage you post? come on!

Aug 01, 2019
This was postulated by plasma physicists, not me. These plasma physicists are largely responsible for modern plasma physics, one of them deemed the Father of Plasma Physics. You can be sure I value their opinion over your willfully ignorant POV.

Aug 01, 2019
However, none of those plasma physicists thought the Sun was powered by the galaxy.

Aug 01, 2019
This was postulated by plasma physicists, not me. These plasma physicists are largely responsible for modern plasma physics, one of them deemed the Father of Plasma Physics. You can be sure I value their opinion over your willfully ignorant POV.


Really? Where has Alfven got pinches forming stars? Or galaxies? Lol. He knew what stars were, and he knew they were powered by nuclear fusion. Peratt is just off his rocker, and has long since given up on his ludicrous galaxy model. And moved on to seeing plasma woo in rock art! We should care about this, why?

Aug 01, 2019
However, none of those plasma physicists thought the Sun was powered by the galaxy.

That is false, one concept leads to the other and they knew it.

Aug 01, 2019
However, none of those plasma physicists thought the Sun was powered by the galaxy.

That is false, one concept leads to the other and they knew it.


Well, that doesn't apply to Alfven, does it? He explicitly said that stars were powered by fusion. And, if I recall, Peratt's galaxy woo said nothing about stars. Not even how he was explaining their rotation curves! Which he can't.

Aug 01, 2019
Stop lying jonesdumb, it's pathetic.

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