I should have used more precise phrasing: All quasars are at the cores of galaxies. I didn’t mean to imply that I thought all galactic cores were quasars.
Didn’t astronomers use the Hubble to observe that some quasars have some surprisingly small host galaxies? Isn’t what’s going on in the immediate vicinity of the galactic core the important variable, not necessarily the size of that galaxy?
I assumed that this thread had been prompted by the (very) small report I read in today’s paper, but apparently not:
This is from The Daily Telegraph, January 11. The articles said “300 million years” but I assume it should have read “300 million light years”.
Doing some Google digging, it appears that this story is based on this: http://www.newswise.com/articles/view/509084/
So, all might not be as it appears. Time to update that Staff Report?
I didn’t actually pull the best quotes out of that news article. To clarify, these guys are basically saying that too many supposedly distant quasars appear to be closely associated with galaxies that are much nearer, and it can’t be coincidence. If they are physically associated with the “nearby” galaxies, then the extreme red shift exhibited by the quasars cannot be due to extreme distance. Which would raise two important issues:
- Quasars are much nearer than we thought
- Something else weird muct be going on to cause the red shift.
Pretty pics here: http://ucsdnews.ucsd.edu/newsrel/science/mcquasar.asp
I must say that to my untrained eye, that quasar doesn’t look like it’s in the middle. But hey, I’ll defer to those astro-dudes 
I’m not all that convinced by this, to be honest, but I’m going to have a read of the paper, and see if that manages to convince me.
It appears that there’s been more than one “ultra-luminous X-ray source” identified with a QSO, and the chances of it being an accidental superposition of a bright X-ray source on a background quasar are slim. All of the objects found lie fairly close to the centres of the host galaxies, and it looks like the QSOs are interacting with the hot gas of the host galaxies. Basically, it looks like something wierd is going on here.
For what? For stuff like active galactic nuclei (AGN), then there is a relationship between the size (and power) of the central active core, and the mass of the galaxy – bigger galaxies host bigger active nuclei.
Well, all other things being equal, the mass of the black hole in the center should be the most important, but something has to be falling into the black hole for the nucleus of the galaxy to be active (at least, that’s my understanding). The more stuff falling in, the brighter any particular nucleus is going to be, will it not? Sure, you’d think a bigger host galaxy would have more stuff to throw into a bigger black hole in its nucleus, but a humongous galaxy could be quiescent, while a modestly-sized galaxy right next door could be blazing, esp. if, for instance, something stirred up the galactic nucleus and sent a lot of matter spiralling into the supermassive black hole it harbors.
Indeed it could. But if both were active at the same time, then the larger galaxy would show more activity.
Which would be the whole analysis, I think. On closer inspection, the paper may be a load of rubbish! Particularly one line in their conclusion where they state that
Firstly, I can’t see what else they can be, apart from quasars at cosmological redshifts. Current understanding is that QSOs are associated with galaxies, specifically, with galactic nuclei, as opposed to binary black hole type things. Secondly, there is a wealth of radio data out there, at many frequencies, which would glarify if there was any interaction between them.
The galaxy group to which NGC7319 belongs is a very well known and well studied group, to say that they need more data is well, silly, as there’s loads of good quality data – as they’ve shown with the Chandra observation they present – its good enough to do some very detailled analysis with.
Something just isn’t ringing quite right about these papers – they don’t do any detailed X-ray analysis, which they could, as the data is there, and which would shed more light on the emission mechanism of the QSO ‘counterpart’. Also, I’m still at a total loss to see how something this bright could be associated with a group of young spirals – it just doesn’t make sense.
I was intrigued for a couple of hours – I’ll confess, I merely skimmed the paper initially, but on a closer read through, something stinks, and I’d take it with a huge pinch of salt.
Not too surprising. It seems to be just another attempt by Geoffrey Burbidge to get everyone else to jump onto his hobby horse. He (and Halton Arp) have been doing this for years: finding coincidental line ups of a quasar and a closer galaxy and claiming that they are associated.
Now I’m not a professional astronomer, just an interested layman. But this has been happening for many years and I’m sure the other astronomers are getting tired of it. Someday, they are going to stop bothering to refute him.
Yes, funny how all his cites on finding other quasars lining up with closer galaxies are all his past papers. Talking to a few others brings up complete and utter scorn for his work too.
What is his (their) hobby horse? Is it just that there are a lot of nearby Quasars, or does he have grander “alternative” cosmologies in mind?
Just curious.
My WAG is that Quasars aren’t natural objects at all, but are gigantic directional beacons constructed by a super-intelligent, hyper-technological alien race (which is now long gone.) The reason they are all at the edge of the universe is (a) that’s the most logical place for directional beacons to be placed, and (b) they have a secondary purpose of telling intergalactic travelers: “WARNING! EDGE OF UNIVERSE AHEAD. REDUCE SPEED.”
…well I didn’t say it was a good theory…
Well, the Burbridges are fairly vehement Bing Bang dissenters.
We believe, well, we can show, that quasars are at what we call “cosmological” redshifts – i.e. redshifts so far away that they start probing the earlier history of the universe. Provided that we believe that the expansion of the universe is causing these high redshifts.
Their theory (as far as I remember it) is that quasars really aren’t at cosmological redshifts, so, there must be something else causing these quasars to look so redshifted, rather than the expansion of the universe (i.e. the Big Bang). Therefore, they state, that if they can prove that the quasars are actually associated with nearby objects, then how can we trust any other object at a cosmological redshift? Hence, the big bang model is incorrect
Personally, I don’t actually know about how they feel about the sex lives of various Friends characters. I do know that they think that the Big Bang (the astronomical theory, not something that Zaphod Beeblebrox’d enjoy) is a load of cobblers.
re Nearby Quasars:
What would it take to restore the Milky Way (if it was ever) to quasar status? From what I remember, HST images of the average quasar host suggest they’ve been perturbed by something in the not-too-distant past, most likely a collision with another object of comparable mass. It follows reasonably that such a perturbation sent large amounts of matter spiralling into the quasar. So what are we talking here, tens, hundreds, thousands of suns’ worth? Apparently, the light from quasars (and Seyferts, actually) varies over the course of days to months. This would suggest the emitting object is quite small compared to galactic scales, less than a few light days or, at most, light-months across, and maybe even a lot smaller. It also suggests that variable amounts of matter are falling into the putative black hole that occupies the active galactic nucleus. Are we seeing the consumption of, say individual stars? Is the flow of matter into the accretion disk relatively constant, but somehow it gets lumpy, and hence you see these variations in luminosity? And if the Milky Way differs from a quasar or a Seyfert only by the density of the galactic nucleus, and the amout of matter accelerating into the supermassive black hole at its center, is it at all conceivable that, say, a collision with another sufficiently massive object like the Sagittarius Dwarf Galaxy, could reactivate the Milky Way’s core?
To be honest, I don’t know; it is a rather active field of research, but not quite my own, although it is tangentially related. I’ll try and do some more digging to answer your queries tomorrow, when I actually can get hold of my recent textbooks, and access journals.
Thanks, and I look forward to the answers. I’m hoping the questions are germain to the OP, because the answers might indicate that there just ain’t enough stuff around these days for quasars and Seyferts to exist, and that has everything to do with why they’re all so far away, and why we may never see one form again.
What would a Quasar look like up close? Would it be something like a galaxy-sized star?
How “up close” do you mean? Too up close is lethal, so it’d be the last thing you saw, regardless of how it looked.
I saw a little mpeg somewhere of a quasar hotting up in a typical spiral galaxy (obviously, this was a simulation, not a recording of actual events as they transpired). Imagine your cameral was placed above the plane of the galactic disk, probably a couple galactic radii away, such that the disk of the galaxy stretches across your entire field of vision, with the bulge of the galactic nucleus in the lower midsection of your view. There’s a brilliantly white glowing object in the center of the bulge, and huge jets of glowing hot gas, one flowing up, one down, roughly perpendicular to the plane of the disk. The object is so bright, it’s impossible to see that the source is a pinpoint from this distance, as it floods its vicinity with an overpowering glow. Slowly, the light intensifies even more, to the point that you can barely even make out the shape of the bulge; it’s like staring right into the sun, only the sun has spiral arms that you can make out dimly in the blaze.
I’m not sure how accurate this representation is, but that’s what it looked like in the movie . 