FR I, FR II

Hello,

I have to write a high-school level project summarising radio galaxies. The
two main classifications of radio galaxies that I have come across are FR I
and FR II. I have found a number of internet descriptions of these and their
differences, but some have seemed a little...well, fuzzy. I was wondering if
someone could confirm or correct the following descriptions I have come up
with after looking at a number of sources:

FR I types show regions of greater radio intensity closer to the core than
regions of lower radio intensities. These are so called edge-darkened
galaxies for this reason.. The lobes and jets of FR I galaxies are often
diffuse, and not well defined. FRI galaxies often exhibit two jets of
similar intensity

FRII AGN exhibit narrower but higher speed jets when compared with FR I's.
These sources sometimes have only one jet, or have two jets but of different
intensities. Regions of lower radio intensity are closer to the core than
the regions of greater intensity. The regions of greater radio intensity are
found on the outer edges of the sources lobes where the high speed jets from
the core intersect the outer edges, terminating in violent shocks (the
"hot-spots" discussed). FR II galaxies are generally more luminous than FR
I galaxies and their lobes are usually more distinct

I think I am posting in the right place. If not, please would you direct me
to an appropriate place.

Thank you.

Curt

Curt wrote:
I have to write a high-school level project summarising radio galaxies. The
two main classifications of radio galaxies that I have come across are FR I
and FR II. [[...]]

I think I am posting in the right place. If not, please would you direct me
to an appropriate place.

You might want to try reposting to sci.astro.research, which deals
with astronomy/astrophysics in general. A number of experts on radio
galaxies are regular posters there.

ciao,

--
-- "Jonathan Thornburg -- remove -animal to reply"
Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut),
Golm, Germany, "Old Europe" http://www.aei.mpg.de/~jthorn/home.html
"Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral."
-- quote by Freire / poster by Oxfam

Curt wrote:
I have to write a high-school level project summarising radio galaxies. The
two main classifications of radio galaxies that I have come across are FR I
and FR II.
...
FR II galaxies are generally more luminous than FR I galaxies

I think this last is the main distinction, though of course there are
many other differences that follow from this main one.

A quick search found a technical review by Urry and Padovani (1995 PASP
107, 803). You should be able to get it at the following link:
http://articles.adsabs.harvard.edu/c...;filetype=.pdf
This is intended for astronomers, but I think parts of it may be clear
enough to meet your needs.

A better place to have posted your query would have been
sci.astro.research ; you might get a better answer there. That's a
good place to ask if you have followup questions.

Curt wrote

I have to write a high-school level project summarising radio
galaxies.
[...]
I think I am posting in the right place. If not, please would you
direct me
to an appropriate place.

I would recommend sci.astro.research.


Regards,
--
Filip Larsen

Thanks,

The technical paper was quite helpful. Thanks for directing me to the
appropriate newsgroup.

Curt