Quasars up close

What would a quasar look like up close? Say, if there was an active quasar
right now at the center of the milky way galaxy? How would it appear from
earth? How bright would it be?

thanks

jjb

What would a quasar look like up close? Say, if there was an active quasar
right now at the center of the milky way galaxy? How would it appear from
earth? How bright would it be?

Hi:

I'd say "purty bright." And you _might_ even see some jet action too.
However...I'd guess that a lot of the fun-stuff would be hidden by those bad
ol' dust clouds, just as Sagittarius A* is in our sedate little spiral.


Peace,
Rod Mollise
Author of _Choosing and Using a Schmidt Cassegrain Telescope_
Like SCTs and MCTs?
Check-out sct-user, the mailing list for CAT fanciers!
Goto http://members.aol.com/RMOLLISE/index.html

(Rod Mollise) wrote in message ...
What would a quasar look like up close? Say, if there was an active quasar
right now at the center of the milky way galaxy? How would it appear from
earth? How bright would it be?

Hi:

I'd say "purty bright." And you _might_ even see some jet action too.
However...I'd guess that a lot of the fun-stuff would be hidden by those bad
ol' dust clouds, just as Sagittarius A* is in our sedate little spiral.

On a similar theme, I'd guess that the milky way must look spectacular
from an observer on the 'nearside' of one of the magellenic clouds.
It would be *huge* in the sky, perhaps not as bright as we might
imagine, but really something amazing to scan with a wide FOV
instrument!

Here's a nice artist's impression of a planet's view of something big!

http://www.exoplaneten.de/Q0957+561/...landschaft.jpg

(it's actually speculating on a 'quasar planet', but it conveys the
general idea nicely)

(Rod Mollise) wrote in message ...
What would a quasar look like up close? Say, if there was an active quasar
right now at the center of the milky way galaxy? How would it appear from
earth? How bright would it be?

Hi:

I'd say "purty bright." And you _might_ even see some jet action too.
However...I'd guess that a lot of the fun-stuff would be hidden by those bad
ol' dust clouds, just as Sagittarius A* is in our sedate little spiral.

On a similar theme, I'd guess that the milky way must look spectacular
from an observer on the 'nearside' of one of the magellenic clouds.
It would be *huge* in the sky, perhaps not as bright as we might
imagine, but really something amazing to scan with a wide FOV
instrument!

Here's a nice artist's impression of a planet's view of something big!

http://www.exoplaneten.de/Q0957+561/...landschaft.jpg

(it's actually speculating on a 'quasar planet', but it conveys the
general idea nicely)

"Jeremiah J. Burton" wrote in message
s.com...
What would a quasar look like up close? Say, if there was an active
quasar
right now at the center of the milky way galaxy? How would it appear from
earth? How bright would it be?


Hi, Look like a (fuzzy) blue star or a small blop looking like a distant
star
See at the end of this page for an image of M87 by David Hanon, 24" scope
http://www.astrosurf.com/lombry/imagesgallery-dso.htm

3C273 by our friend Kaz Tanaka, with a C8
http://www.astrosurf.com/lombry/spectro-3c273-c8.htm
See also 2/3d of this page for 2 location maps (in the box "Localiser
3C273") at mid and HR.

Otherwhise it is very hard to get better pictures.

Thierry


thanks

jjb

"Jeremiah J. Burton" wrote in message
s.com...
What would a quasar look like up close? Say, if there was an active
quasar
right now at the center of the milky way galaxy? How would it appear from
earth? How bright would it be?


Hi, Look like a (fuzzy) blue star or a small blop looking like a distant
star
See at the end of this page for an image of M87 by David Hanon, 24" scope
http://www.astrosurf.com/lombry/imagesgallery-dso.htm

3C273 by our friend Kaz Tanaka, with a C8
http://www.astrosurf.com/lombry/spectro-3c273-c8.htm
See also 2/3d of this page for 2 location maps (in the box "Localiser
3C273") at mid and HR.

Otherwhise it is very hard to get better pictures.

Thierry


thanks

jjb

In message m,
Jeremiah J. Burton writes
What would a quasar look like up close?

It depends on the angle you are looking at it from and at what
wavelength(s). Inside the region along the relativistic beaming it will
be extremely bright. Far off axis you will see less due to obscuration
by gas and dust but possibly something from the jets interaction forming
hot spots.

3C273 and M87 are about as good targets as any to give a rough idea. HST
has also imaged some detail of the inner workings of NGC4261 and perhaps
6251.

ISTR the absolute visual magnitude of 3C273 is around -27 whereas our
own sun is a puny 4.8

I expect HST/Chandra/VLA images of other relatively nearby objects with
active galactic nuclei will give you a reasonable flavour of appearance.
Quasars is sometimes reserved for radio loud quasi-stellar objects. You
will get a bigger selection by searching on QSO or AGN.

Say, if there was an active quasar
right now at the center of the milky way galaxy? How would it appear from
earth? How bright would it be?

In the visual there is probably far too much gas and dust in the way to
see it at all. However it would be pretty amazing in the X-ray and radio
bands. Since there is almost certainly a BH at our galactic centre
things can be expected to hot up in about 4-5GY when Andromeda churns
things up.

Also you might be able to see the two hot spots where the jets impinge
upon the tenuous extragalactic medium since they will be well out of the
galactic plane. You can get some idea of how it might look in the radio
from the Cygnus-A radio galaxy where the jets are roughly in the plane
of the sky and one has been observed directly by the VLA at 5GHz.

Regards,
--
Martin Brown

In message m,
Jeremiah J. Burton writes
What would a quasar look like up close?

It depends on the angle you are looking at it from and at what
wavelength(s). Inside the region along the relativistic beaming it will
be extremely bright. Far off axis you will see less due to obscuration
by gas and dust but possibly something from the jets interaction forming
hot spots.

3C273 and M87 are about as good targets as any to give a rough idea. HST
has also imaged some detail of the inner workings of NGC4261 and perhaps
6251.

ISTR the absolute visual magnitude of 3C273 is around -27 whereas our
own sun is a puny 4.8

I expect HST/Chandra/VLA images of other relatively nearby objects with
active galactic nuclei will give you a reasonable flavour of appearance.
Quasars is sometimes reserved for radio loud quasi-stellar objects. You
will get a bigger selection by searching on QSO or AGN.

Say, if there was an active quasar
right now at the center of the milky way galaxy? How would it appear from
earth? How bright would it be?

In the visual there is probably far too much gas and dust in the way to
see it at all. However it would be pretty amazing in the X-ray and radio
bands. Since there is almost certainly a BH at our galactic centre
things can be expected to hot up in about 4-5GY when Andromeda churns
things up.

Also you might be able to see the two hot spots where the jets impinge
upon the tenuous extragalactic medium since they will be well out of the
galactic plane. You can get some idea of how it might look in the radio
from the Cygnus-A radio galaxy where the jets are roughly in the plane
of the sky and one has been observed directly by the VLA at 5GHz.

Regards,
--
Martin Brown

Sorry to chime in late, but I haven't been monitoring SAA regularly.

Martin Brown wrote:
In message m,
Jeremiah J. Burton writes
What would a quasar look like up close?

3C273 and M87 are about as good targets as any to give a rough idea.

M87 isn't a quasar at all, it's a nonthermal radio galaxy. In any case,
Sag A* (the black hole at the center of our Galaxy) isn't huge as such
things go, and if it were more active it would probably appear as a type
2 Seyfert rather than an obscured quasar.

Quasars is sometimes reserved for radio loud quasi-stellar objects.

Right, and AFAIK there is only 1 known radio-loud active galaxy with a
spiral host. There is also an optical luminosity cutoff for quasars.

Say, if there was an active quasar
right now at the center of the milky way galaxy? How would it appear from
earth? How bright would it be?

In the visual there is probably far too much gas and dust in the way to
see it at all. However it would be pretty amazing in the X-ray and radio
bands.

Yep. And though you might not see it directly in visual, the optical/UV
continuum would create a nice extended narrow emission line region, and
there might be some indirectly visible scattered light. It happens.

Since there is almost certainly a BH at our galactic centre

At this point, I think you can drop the "almost."

Also you might be able to see the two hot spots where the jets impinge
upon the tenuous extragalactic medium since they will be well out of the
galactic plane. You can get some idea of how it might look in the radio
from the Cygnus-A radio galaxy where the jets are roughly in the plane
of the sky and one has been observed directly by the VLA at 5GHz.

It is unlikely that there would be any substantial jets. Spiral hosts almost
always produce Seyferts, which don't have strong radio jets. In any case,
Cyg A is a special case -- much of it's radio-loudness and lobe structure
is due to being in a cooling flow (intra-cluster medium). It does harbor
a hidden quasar nucleus though.

Do an ADS search on my name for details...

- Dave

David Whysong
DWhysong (at) physics (dot) ucsb (dot) edu

David Whysong wrote:

Sorry to chime in late, but I haven't been monitoring SAA regularly.

Martin Brown wrote:
In message m,
Jeremiah J. Burton writes
What would a quasar look like up close?

3C273 and M87 are about as good targets as any to give a rough idea.

M87 isn't a quasar at all, it's a nonthermal radio galaxy. In any case,
Sag A* (the black hole at the center of our Galaxy) isn't huge as such
things go, and if it were more active it would probably appear as a type
2 Seyfert rather than an obscured quasar.

Mind you, M87 might make a tolerable blazar is seen from about 40 degrees
away in the right direction. Trying to fit the jet structure gives
a cool example of relativistic effects; planar objects (shocks, for example)
moving outward with a relativistic flow wil look more edge-on than they
really (i.e. geometrically) are, since the back side is seen at an earlier
stage in the flow. This may have once been called a Lorentz rotation.

Quasars is sometimes reserved for radio loud quasi-stellar objects.

Right, and AFAIK there is only 1 known radio-loud active galaxy with a
spiral host. There is also an optical luminosity cutoff for quasars.

You rang? Gotta add the new Chandra results one of these days.
Sad to say, I just learned that Mike Ledlow, who played a big
part in work on the radio-loud spiral 0313-192, died suddenly
this week in Colorado. Kinda makes me forget that pesky appendectomy
last week.


Bill Keel