Images of gamma-ray flare from supermassive black hole M87 | Hacker News Reader

Images of gamma-ray flare from supermassive black hole M87

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58 pointsgmays18 comments

The M87 jet can be optically imaged by amateurs too, here is an image I took using a 400mm (focal length) f/2.8 camera lens, a cooled cmos sensor, and many hours of observation: https://nt4tn.net/astro/M87jet.png

The image is a crop and contrast boost of this image: https://nt4tn.net/astro/virgo2.jpg

Light pollution renders such observations increasingly difficult, of course... but Marin's ban on outdoor advertising at least makes it possible here, unlike much of the bay area where stars can hardly be observed at all.

Fantastic shot! What's your mount/tracker?

That was done with a skywatcher EQ6.

With a cooled camera shot noise from light pollution for me starts to dominate readout noise at only 5-10 second exposures for color, so in some sense the mount's stability and tracking matter less... since the ideal exposure time is fairly short. (consequence is that I end up with hundreds of gigs of data to juggle, but I'd rather have to throw more computer power at something then deal with mechanical considerations).

Damn, AUD$6.5k, that's WELL outside my range. I'm lucky here in Western Australia; it's relatively easy to get comparatively dark skies - I've not met any amateurs that have a cooled CCD.

I paid $1700 USD-ish. I'm aware many products have a higher price in AU but that's pretty extreme! :)

OTOH, dark skies plus a view of the southern sky is something to be jealous of. :P

Earlier this year I was in eastern AU (and visited the Anglo Australian Telescope-- an amazing instrument). I was impressed by the skies there, I can only imagine what it's like out west without Sydney right over the horizon.

Very recently CMOS sensors have caught up with cooled CCDs for many purposes and have the benefit of being radically cheaper. There are a couple of vendors with products in the same ballpark as DSLRs with similar sized sensors (though obviously without the benefit of being particularly useful as stills cameras). or hum, are in the US at least. :P

The benefit of the cooled sensor is increased with darkier skies too, due to the relative ratio of sensor noise to sky background shotnoise.

What blows my mind is the fact that the jet emanating from M87 is thousands of lightyears across. This means you could live out your life on a planet orbiting a star near the jet and probably wouldn't notice anything out of the ordinary. The scale of that structure is absolutely mind-boggling.

Wouldn't that ray destroy any life on any nearby planet?

I think the poster above meant "wouldn't notice anything out of the ordinary until it's too late."

I just wish there were a higher resolution image than the one linked in that website. The original photos of M87 are so stunning and have such a cool story where they split the research group into two teams and they both came to the same conclusion about the discovery of the black hole. The photos that go along with the original discovery were my wallpaper forever because it just looks so awesome.

There is some amount of controversy of the EHT imaging process because there are pretty strong priors backed into it (like a lot of modern physics observations, e.g. LIGO)-- and at least one group suggests that you get a similar looking donut observation if you just feed noise into their imaging process.

Too see the flare from the side bothers me the most. There's so much energy traveling away from us that it's lighting up space enough for the flare, again not pointing at us, to outshine the galaxy.

Yeah if it was pointing this way we won't see it presumably.

Do we mean we would not see it because it would appear to be a point source which we could not resolve, or do you we could not see it because it would quickly kill us?

If the latter, note that it is 53 million light years. That's far enough that it should pose no danger at all even if aimed right at us.

Apparently we should be able to see it brightly if it was far away... But if it was close enough will we have time between light & gamma arrival?

something i've wondering, does a jet like this "push" the blackhole in any way?

Usually active blackholes produce two jets, above and below the accretion disk. They cancel each other out.

It must right? (even if very slightly), otherwise it'd be in violation of Newton's 3rd law of motion.

Uhh, Newtonian physics doesn't really apply to black holes very well. You would be hard pressed to conclude ANYTHING about black holes using Newton's laws and equations and end up with the right answer except by accident.

That being said, momentum is conserved, so if there was only a single jet then the "black hole system" minus the jet would have momentum. However, I don't think we've ever seen a single jet black hole.

Also keep in mind we have a rather poor understanding of black holes, and that a lot of information that is stated as "we know X about black holes" is actually "general relativity equations evaluate to X" and has not been observed or verified by data. There's still serious open questions about their physics.

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