Strange X-rays point to possible ‘dark’ matter

An orbiting telescope has just spotted a strange X-ray signal. It’s raising hopes that the source may be dark matter. That’s the unknown — and unseen — substance that scientists believe constitutes most of the matter in the cosmos.

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The Chandra bump, as I call it, has been puzzling astronomers for a decade or more. It was originally seen in X-rays coming from the centre of the milky Way.

As the article says, the bump has sometimes been seen and sometimes not been seen. In terms of frequency, it’s consistent with WIMP dark matter. But in terms of strength, it’s far too weak to be generated by dark matter self-interaction. Hence the puzzle. It could be, for instance, a fault in the Chandra optics.

This new results claims that the distribution of the bump with angle corresponds to the distribution of dark matter in space, a claim that’s well worth checking out.

To be continued …

https://m.phys.org/news/2017-02-plot-chandra-x-ray-observatory-reveals.html

https://arxiv.org/pdf/1411.1758
Hitomi constraints on the 3.5 keV line in the Perseus galaxy cluster

https://arxiv.org/abs/1607.07420
A critical look at the 3.5 keV line – UCLA.edu

http://www.mso.anu.edu.au/iau322/tjeltema.pdf

https://en.wikipedia.org/wiki/Warm_dark_matter
Warm dark matter (WDM) is a hypothesized form of dark matter that has properties intermediate between those of hot dark matter … We can cite, for example, a 3.5 keV candidate annihilating into 2 photons.

https://telescoper.wordpress.com/2016/07/26/the-3-5-kev-line-that-wasnt/
The 3.5 keV “Line” that (probably) wasn’t… | In the Dark

http://www.symmetrymagazine.org/article/dark-matter-hopes-dwindle-with-x-ray-signal

https://indico.cern.ch/event/325123/contributions/755829/attachments/630486/867688/PPTalks_JC.pdf
The 3.5 keV line – CERN Indico

I find the lack of forum feedback depressing. There is no more controversial or important topic in observational astronomy.

quote=Tau.Neutrino]
The brightest, most distant pulsar has a complex and powerful magnetic field

The supermassive black holes found at the centers of galaxies are known for their extreme X-ray emission. This emission is associated with the massive hot disks of gas and debris that circle these monstrous black holes before it is consumed.

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Tau.Neutrino said:

The brightest, most distant pulsar has a complex and powerful magnetic field

The supermassive black holes found at the centers of galaxies are known for their extreme X-ray emission. This emission is associated with the massive hot disks of gas and debris that circle these monstrous black holes before it is consumed.

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These are ULXs, or ultraluminous X-ray sources. ULXs have been traditionally explained as large stellar-sized (80-100 solar masses) or possibly intermediate mass (1,000-100,000 solar masses) black holes accreting material at high rates. Now, one famous ULX has been identified not as a black hole, but as a neutron star with a mass less than 1.5 that of our Sun,

Darn, I was hoping they were all intermediate mass black holes.

“Just how brightly can a neutron star shine?”

Yes, that is indeed the question.

“ULX-1 in NGC 5907”

Let’s see what I said about that recently. I didn’t, it wasn’t on my list of ultraluminous x ray sources that were tentatively identified as intermediate mass black holes.

“periodic variations in the X-rays coming from this object, which they’ve now identified as a pulsar (a spinning neutron star). Furthermore, this pulsar is accreting material at such high rates that it’s spinning up, dramatically increasing the speed at which it rotates around its axis. They measured the pulsar’s period as 1.43 seconds in 2003, while observations made in 2014 clocked the pulsar at a faster rotation rate of 1.13 seconds. In a video accompanying the announcement, Israel compared this speed-up to the Earth’s day growing shorter by 5 hours in just 11 years. The pulsar is both the farthest and brightest X-ray pulsar detected to date. Its intense radiation can only be explained by the presence of an extremely strong multipolar magnetic field, such as the type of magnetic field found in magnetars. “

“Eddington limit”.

This object puts even magnetars to shame, and that’s saying something!