Subject: z2p5 notes #4
Date: Fri, 27 Mar 1998 15:54:44 +0100
From: Bob Fosbury <rfosbury@eso.org>
Organization: ST-ECF
To: Andrea Cimatti <cimatti@arcetri.astro.it>, Bob Fosbury <rfosbury@eso.org>,
     Bob Goodrich <goodrich@keck.hawaii.edu>, Joel Vernet <jvernet@eso.org>,
     Marshall Cohen <mhc@Deimos.Caltech.Edu>,
     Montse Villar <M.Villar-Martin@sheffield.ac.uk>,
     Sperello di Serego Alighieri <sperello@arcetri.astro.it>

Just to keep you occupied over the weekend, here is another correlation to ponder.
As you remember, we see an anticorrelation between P and Ly-a/CIV which we
think is telling us something about dust and/or geometry.
The latest version of this plot is in:
http://ecf.hq.eso.org/~rfosbury/research/z2p5/P_Lya.gif
where I have included F10214-4724 from the Keck data.

On perusing the data further and reading the papers by the Miley group, I
plotted P vs. NV/CIV to get:
http://ecf.hq.eso.org/~rfosbury/research/z2p5/P_NV.gif
(which also includes F10214).
... Remember the polarization is measured in the continuum just logward of NV...

Now this looks pretty striking to me. But what is the NV telling us?

How about the following as a scenario...
The NV/CIV (=> nitrogen abundance) is increased by starbursts which can make
N/C 5-10 times solar in quite a short time. These starbursts are responsible
for a similarly rapid increase in the dust/gas ratio. The increasing amounts
of dust increase the fractional polarization and kill Ly-a.

Tell me where I'm wrong?

Have fun...
Bob...
--
R A E Fosbury (Bob)
Space Telescope - European Coordinating Facility
rfosbury@eso.org, http://ecf.hq.eso.org/~rfosbury/
Tel:+49 89 320 06 235 (o)  +49 89 609 9650 (h)   Fax:+49 89 320 06 480