From: william edmondson (w.h.edmondson_at_cs.bham.ac.uk)
Date: Wed Sep 29 2004 - 04:15:30 PDT
Hi Paul, Elisabeth, Folks...
Paul - and maybe others - the horizontal axis is labelled in the centre
of the figure - visibility may depend on your pdf viewer (they are
indeed rather faint). And yes - 0 on left, 24 on right.
Concentration of pulsars - note that that is particularly obviously in
the galactic plane for the slow ones. Simply means they are further
away (I gather). The fast ones, being isotropically distributed (sort
of) are closer.
Having said that, I gather that pulsar searches tend to concentrate in
the galactic plane, and indeed toward the centre. Just ups the chances
of finding one, I suppose.
Note that the pulsar/beacon idea only works sensibly for Habstars which
not too far away, and the fast pulsar distribution means that we end up
sampling the nearer Habstars reasonably uniformly. One plot I suppose
I might have put up would be that showing Habstar distribution. I just
spent an half an hour or so trying to sort out a reasonable plot for
folks to look at. Go to http://www.cs.bham.ac.uk/~whe/image001.gif and
you will see 17129 Habstars from Turnbull and Tarter plotted by ra and
dec.
Curiously not quite on the galactic plane as shown in Figure 1 of the
paper (no doubt someone can explain that) but pretty densely/evenly
distributed..... I suspect the sampling distortions don't matter.
I will post a couple more emails about this work - just to keep them
short.
Thanks for your attention.
William
On 29 Sep 2004, at 00:08, Dr. H. Paul Shuch wrote:
> William Edmondson wrote:
>
>> (http://www.cs.bham.ac.uk/~whe/SETIPaper.pdf)
>
> Great paper, William. I hadn't yet seen it; thanks for passing along
> the URL. The tables are especially valuable.
> I'm curious about the RA axis of Figure 1, as no units are specified.
> May I assume it is 0:00 at the left and 24:00 at the right?
> To what extent does the apparent concentration of pulsars in the
> galactic plane reflect selectivity effects (that is, are we looking
> for them primarily in the plane of the Milky Way?)
>
>> Some good news too - working with a few colleagues I will be using
>> the Arecibo dish to do some SETI as set out in that paper.
>
> Good news indeed. Happy hunting!
> Cheers -- Paul
>
>
> --
> H. Paul Shuch, Ph.D. Executive Director, The SETI League, Inc.
> 433 Liberty Street, PO Box 555, Little Ferry NJ 07643 USA
> voice (201) 641-1770; fax (201) 641-1771; URL
> http://www.setileague.org
> email work: n6tx_at_setileague.org; home: drseti_at_cal.berkeley.edu
>
> "We Know We're Not Alone!"
>
>
>
Dr William Edmondson
School of Computer Science
University of Birmingham
Edgbaston B15 2TT
UK
Voice: +44-121-414-4763
email: w.h.edmondson_at_bham.ac.uk
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