4 ms·
Our deepest view of the X-ray sky
- xioxox 6y agoThe eROSITA telescope onboard the SRG observatory has completed its first survey of the sky in X-rays, producing the deepest ever map in X-rays and finding over a million sources. Most of these sources are active black holes, clusters of galaxies, supernova remnants and stars. Annotated and high res images can be found here: http://www.mpe.mpg.de/7461950/erass1-presskit http://www.mpe.mpg.de/7461950/erass1-presskit
- ncmncm 6y agoImagine a whole article about high-energy astronomy never even mentioning plasma or synchrotron radiation. Trotted out "hot gas", though.
- ncmncm 6y agoI am mistaken: "plasma" appears once in a hidden caption I missed first time through.
- xioxox 6y agoI'm not sure why you're bringing up synchrotron radiation in particular. Although it's important for some sources, it's not driving the majority of what is being seen here. Comptonization is important for active black holes. The radiation from the milky way has strong emission lines - it's not a synchrotron spectrum. Mostly thermal emission is emitted from clusters of galaxies. There are a lot of different emission processes to consider in astrophysics.
- ncmncm 6y agoIf, as you say, there are a lot of different emission processes, why only ever mention the, by far, least interesting? Elsewhere in science exceptions are interesting. The unexplained is interesting. Lev Landau is reputed to have said, "Cosmologists are often in error, never in doubt." Doubt is productive.
- gattr 6y ago"But wait, how can you perform telescopic observations in X-rays? They tend to penetrate matter (including telescopes), right?" Correct, normal optics would not work. X-ray telescopes use grazing incidence mirror arrangement (Wolter telescope [1] [2]). [1] https://en.wikipedia.org/wiki/Wolter_telescope https://en.wikipedia.org/wiki/Wolter_telescope [2] https://en.wikipedia.org/wiki/EROSITA https://en.wikipedia.org/wiki/EROSITA
- xioxox 6y agoI'm a scientist on the team who did this (I actually helped put this picture together), so I can try to answer questions...
- someguydave 6y agoHas the eROSITA mission discovered any previously unknown black holes?
- xioxox 6y agoLots! It has discovered about a million X-ray sources, about twice as many as previously known about. Most of these sources will be active galactic nuclei (supermassive black holes that are accreting material) in distant galaxies. There's still lots of work to do in characterising these objects though and understanding the population.
- SiempreViernes 6y agoThe Fermi bubbles are super-prominent, is eROSITA the first x-ray telescope sensitive to detect them?
- xioxox 6y agoSome of the structure can be seen in the old ROSAT maps from the 90s: http://www.xray.mpe.mpg.de/rosat/survey/sxrb/12/ass.html http://www.xray.mpe.mpg.de/rosat/survey/sxrb/12/ass.html Recently XMM looked at the centre of the galaxy, finding chimney-like structures which may link to the bubbles. This is on a much smaller region, however: http://www.esa.int/Science_Exploration/Space_Science/Giant_chimneys_vent_X-rays_from_Milky_Way_s_core http://www.esa.int/Science_Exploration/Space_Science/Giant_c... Nothing since ROSAT has had the ability to map large areas like eROSITA/SRG. ABRIXAS was supposed to be the successor to ROSAT, but it failed shortly after launch.
- SiempreViernes 6y agoAnd what is the angular resolution of the real thing?
- staycoolboy 6y agoThis just blew my mind, from the fifth image: "Vela Junior was discovered just 20 years ago, although this object is so close to Earth that remains of this explosion were found in polar ice cores." Aside from being some serious Hurcule Poirot meets Kip Thorne crossover stuff, I want to ask "How do we know?" but I'm pretty sure I wouldn't understand the answer.