back to article Black hole swallows star in GALACTIC SUPER-GUZZLE!

With billions of galaxies to choose from, it shouldn’t be hard to catch, but it is. Astronomers are celebrating after capturing the whole sequence of a star falling into a supermassive black hole. The event happens roughly once every 10,000 years per galaxy*, but you still have to be looking in the right place at the right time …

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WTF?

This doesn't make sense:

"Finding mostly hydrogen left behind by the event, Gezari’s paper in Nature (abstract) suggests that the doomed star was a red giant with a helium core. Hydrogen – the other key stellar fuel – is nearly absent from the sample, suggesting that the lighter element was long-ago stripped by the black hole, leaving helium to make up most of the ejected gas."

"mostly hydrogen left behind" != "Hydrogen ... nearly absent from the sample"

WTF?

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Holmes

Re: This doesn't make sense:

I saw that too, must be a typo by our infallible Reg reporter.

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Anonymous Coward

This bit made me have to think twice too.

>"With billions of galaxies to choose from, it shouldn’t be hard to catch, but it is."

That sentence just tripped me up as I was reading it. Intellectually I know what it's saying, but intuitively it just does not compute. Compare:

"With billions of places to look in, it should be easy to find my lost keys".

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Re: This bit made me have to think twice too.

Billions of places to look and only one set of keys; hard to find

Billions of places to look and potentially billions of keys; not quite so hard to find.

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Anonymous Coward

So how rare is this?

How many galaxies are there within observable distance? When multiplied by the 1/10,000 years, just how infrequent is this really?

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Alien

Re: So how rare is this?

Well a quick search reports that there are 100 to 200 billion galaxies in the observable Universe. So the occurrence is quite often BUT you have to be looking at the right Galaxy at the right time, a 1 in 100 billion chance?

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Happy

Re: So how rare is this?

If only it were a one in a million chance, we would see them every time

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Re: So how rare is this?

Well, 9 times out of 10 at least...

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Anonymous Coward

I had a feeling this had happened

.. as though a million voices cried out and then were silenced

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These aren't the gasses you are looking for.

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Erm

Asteroid is the term you are seeking, Astroid is a mathematical thing

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Joke

So are they still watching?

Are they now waiting for the massive UURRRP after it swallowed that lot?

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Coat

Re: So are they still watching?

Also the possibility of another massive gas ejection some time later.

They may keep that quiet though, after all: He who detected it, ejected it.

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Anthropomorphism

Surprised it hasn't been labled The Gullet of God.

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Alien

Re: Anthropomorphism

I have been 'reliably' informed that stars are the homes of Angels (apparently it needs capitalisation), how cruel it is for humans to be gleeful at the death of countless spirit beings.

Hopefully, The Flying Spaghetti Monster (all hail His Noodleness) was not in the vicinity at the time.

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Angel

FSM

is in all vicinities at all times.

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(Written by Reg staff)

Re: Image questions

Readers,

Since the images have cause some consternation, I have posted this addendum to the story:

Update: About the image: some commenters have had trouble working out what's going on. The top two images are UV, with more magnification on the right, showing the flare emerging. The bottom two are visual, showing the same sequence.

El Reg doesn't agree that they show different regions of space (although they're in slightly different field of view). What they do show, for example in object in the bottom-left corner, is that something quite faint in the visual spectrum can be quite loud in the UV.

Cheers,

Richard Chirgwin

aka The Guilty Party

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Re: Image questions

Hello Richard. Whilst I don't think anything nefarious is going on here there certainly appear to be some anomalies between the two sets of pictures that go beyond your explanation.

The difference between the UV left and right images isn't due to magnification differences but is down to post-processing; the left image has been post-processed to consolidate the features and remove the noise whereas the right image hasn't. It's easy to identify ten clear features in the left image (counting the elongated feature below the bright top-left feature as a single feature, even though it's almost certainly two closely aligned sub-features) and these ten features can, with a little effort and careful scrutinisation, be identified and mapped onto the right image. These two images are at the same scale and show the same region of space. As to why the right image hasn't been post-processed in the same way as the left image; due to the magnitude of the flare feature, I suspect that the same level of post-processing would result in the new flare feature merging with the two pre-existing features closest to it (above and to its upper right). This is ok though because, as I say, it's possible to map these two images on to each other anyway.

The major issue between the upper and lower sets of images is because it's not possible to map the upper set of images on to the lower set of images.

For example: in both of the visual images, the flaring galaxy is located a little to the right of a line between the two bright white galaxies but in the UV images it is clearly a little to the left of the same line between the same two corresponding features (and the relative angular distances between the flaring galaxy and these two features is different). Another clear anomaly is that the elongated feature (referred to earlier) in the UV images 'points' nearly exactly towards the flare feature (slightly below it, in fact) but there's no comparable feature in the visual images.

In fact, it's the number of features that only appear in the UV images, that are missing from the visual+IR images, that most bothers me. Whilst many astronomical objects may be invisible in UV but visible in other frequencies (which is supposed to be the main point of the two sets of images), the opposite isn't true; there are relatively few types of object that are _only_ visible in UV (mostly some types of AGN and their associated relativistic jets), yet these UV images appear to show many of them in a relatively small region of space.

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Images puzzle

The two sets of images (upper and lower) don't appear to match each other, even allowing for the fact that the upper GALEX images are in UV and the lower Pan-STARRS images are in visible+IR i.e. they don't seem to be showing the same region of space

The prominent 'triangle' formed by the three brightest objects in each set of images suggests that the two sets of images are at the same scale but it's just not possible to map one set of images over the other; the alignments are actually only vaguely similar, implying that the scales are completely different or that they're not showing the same region of space.

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Re: Images puzzle

Different scales and lower images are rotated 180?

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