From boud w astro.uni.torun.pl  Fri Mar  2 07:48:23 2012
From: boud w astro.uni.torun.pl (Boud Roukema)
Date: Fri, 2 Mar 2012 07:48:23 +0100 (CET)
Subject: [Cosmo-torun] @14:00 @KRA OK? [Re: cosmo workshop Fri 2 March
 @15.00 @KRA: Jan Ostrowski on Cactus: numerical relativity]
In-Reply-To: <CANMnsZJZZ0tqMpP7S7wAnajYLF5HRDTfzrtvA8nzvDXS-BpsxA@mail.gmail.com>
References: <alpine.DEB.1.10.1202292005270.29578@adjani.astro.uni.torun.pl>
	<CANMnsZJZZ0tqMpP7S7wAnajYLF5HRDTfzrtvA8nzvDXS-BpsxA@mail.gmail.com>
Message-ID: <alpine.DEB.1.10.1203020746260.22921@adjani.astro.uni.torun.pl>

hi everyone,

On Wed, 29 Feb 2012, Tomasz Kazimierczak wrote:

> Could we start a little bit ealier,
> for example @14:00?

Does anyone (especially Jan!) have a problem with starting at 14:00 ?

See everyone this afternoon :)

pozdr
boud


> 
> I have "dyżur" at control room starting at 16:00.
> 
> 2012/2/29 Boud Roukema <boud w astro.uni.torun.pl>
>       hi cosmo-torun
>
>        Cactus: numerical relativity
>        cosmo workshop Fri 2 March @15.00 @KRA
>        Jan Ostrowski
> 
>
>       Jan is doing very interesting work in finding out how to do numerical
>       relativity. One way of saying it is the following:
>
>       "Normal" cosmological N-body simulations consist of *Newtonian*
>       gravity simulated on a highly simplified (perfectly homogeneous)
>       relativistic "background". In formal scientific language, this is
>       called a "heuristic" approach; in informal language, it's called "a
>       fudge" - it's a mathematical shortcut that seems like it should work
>       and lets us quickly compare some sort of "model" to observations
>       instead of waiting 50 years for the mathematics to be solved. In
>       principle, every scientist using the heuristic/fudge is aware of
>       this. Pure theory is very difficult to apply to the real world.
>
>       Relativistic cosmological simulations should be "directly"
>       relativistic, consistent with the Einstein equations, without using
>       the heuristic/fudge of adding "perturbations" that obey Newtonian
>       gravity to a relativistic "background". So these simulations can be called
>       "background-free".
>
>       How can we do background-free cosmology simulations?
>
>       Jan will present a discussion on this.
>
>       pozdr
>       boud
>
>       _______________________________________________
>       Cosmo-torun mailing list
>       Cosmo-torun w cosmo.torun.pl
>       http://cosmo.torun.pl/mailman/listinfo/cosmo-torun
> 
> 
> 
>

From ostjan w stud.umk.pl  Fri Mar  2 08:24:30 2012
From: ostjan w stud.umk.pl (ostjan w stud.umk.pl)
Date: Fri, 02 Mar 2012 08:24:30 +0100
Subject: [Cosmo-torun] ok
Message-ID: <20120302082430.sc2ofy7jhccsws80@poczta.stud.umk.pl>

fine with me



From boud w astro.uni.torun.pl  Mon Mar  5 21:23:28 2012
From: boud w astro.uni.torun.pl (Boud Roukema)
Date: Mon, 5 Mar 2012 21:23:28 +0100 (CET)
Subject: [Cosmo-torun] next workshop plans [Re:  ok]
In-Reply-To: <20120302082430.sc2ofy7jhccsws80@poczta.stud.umk.pl>
References: <20120302082430.sc2ofy7jhccsws80@poczta.stud.umk.pl>
Message-ID: <alpine.DEB.1.10.1203052118400.16914@adjani.astro.uni.torun.pl>

hi cosmo-torun

A tentative timetable for the next workshops:

Fri 16 March: Boud 
On the topological implications of inhomogeneity  arXiv:1201.5845

Fri 23 March: Jan
Cactus/Einstein toolkit II

pozdr
boud


On Fri, 2 Mar 2012, ostjan w stud.umk.pl wrote:

> fine with me
>
> _______________________________________________
> Cosmo-torun mailing list
> Cosmo-torun w cosmo.torun.pl
> http://cosmo.torun.pl/mailman/listinfo/cosmo-torun



From boud w astro.uni.torun.pl  Fri Mar 16 13:18:42 2012
From: boud w astro.uni.torun.pl (Boud Roukema)
Date: Fri, 16 Mar 2012 13:18:42 +0100 (CET)
Subject: [Cosmo-torun] kashlinsky large-scale flow
Message-ID: <alpine.DEB.2.00.1203161307520.14821@adjani.astro.uni.torun.pl>

hi cosmo-torun,

During today's Sprawozdanie, Bronek asked about the Kashlinsky
large-scale high-velocity flow. You'll find Kashlinky's work referred
to in the paper below, which is an interesting observational analysis
according to which the flow is due to using an incorrect choice of the
comoving coordinate reference frame. Wiltshire et al's argument is based on
Wiltshire's approach to modelling the Universe in a more
relativistically correct way than the FLRW ("standard") metric, i.e. one of
the "inhomogeneous" approaches to cosmology (according to which the Earth is
assumed to exist).

http://arxiv.org/abs/1201.5371
Hubble flow variance and the cosmic rest frame
Authors: David L. Wiltshire, Peter R. Smale, Teppo Mattsson, Richard Watkins

pozdr
boud



From boud w astro.uni.torun.pl  Thu Mar 22 10:54:19 2012
From: boud w astro.uni.torun.pl (Boud Roukema)
Date: Thu, 22 Mar 2012 10:54:19 +0100 (CET)
Subject: [Cosmo-torun] cosmo books [was: Re: Fw: Kosmos]
In-Reply-To: <001d01cd0806$5c65e4e0$32064b9e@BIBLIOTEKA>
References: <001d01cd0806$5c65e4e0$32064b9e@BIBLIOTEKA>
Message-ID: <alpine.DEB.2.00.1203221023180.30270@adjani.astro.uni.torun.pl>

witam cosmo-torun

On Thu, 22 Mar 2012, Biblioteka CA UMK wrote:

> Mam prosbe o popatrzenie na zalacznik - czy taka ksiazka-album o Kosmosie
> znajdzie wsrod Panstwa czytelnikow.
...

>> W nawiazaniu do rozmowy telefonicznej przesyłam w załączniku dodatkowe
>> informacje na temat wspaniałego albumu Gilesa Sparrowa  -  KOSMOS.
>> Zapraszam na www.kmktychy.pl


Talking about the "edge of space" in an abstract to a popular
astronomy+cosmology book

  http://www.amazon.com/Cosmos-Giles-Sparrow/dp/1905204299

seems like a bad pedagogical strategy to me. We need to understand the
observer's point of view, but our standard model is based on an
underlying spacetime (pseudo-4-manifold + metric that solve the
Einstein equations), not just a past time cone.

It might be nice as a "coffee table book" - it's motivational to see
big beautiful pictures. On the other hand with a small (zero) budget,
i would tend to go for research/teaching-level books.

At the moment we have three books listed on our wiki - please anyone
update the wiki page:
    http://cosmo.torun.pl/foswiki/bin/view/Cosmo/BibliotekaCosmo
    what we want
       * Padmanabhan, 1993  Structure Formation in the Universe
       * Schilpp 1949  Albert Einstein: philosopher-scientist
       * Bolejko et al 2009 Structures in the Universe by Exact Methods

Schilpp 1949 has the Infeld cosmic topology comment about electromagnetism -
apparently the first person to talk about physical "effects" of cosmic
topology.

pozdr
boud

From boud w astro.uni.torun.pl  Thu Mar 22 11:02:00 2012
From: boud w astro.uni.torun.pl (Boud Roukema)
Date: Thu, 22 Mar 2012 11:02:00 +0100 (CET)
Subject: [Cosmo-torun] workshop 14:00 Fri 16 March: On the topological
 implications of inhomogeneity arXiv:1201.5845
In-Reply-To: <alpine.DEB.1.10.1203052118400.16914@adjani.astro.uni.torun.pl>
References: <20120302082430.sc2ofy7jhccsws80@poczta.stud.umk.pl>
	<alpine.DEB.1.10.1203052118400.16914@adjani.astro.uni.torun.pl>
Message-ID: <alpine.DEB.2.00.1203221055080.30270@adjani.astro.uni.torun.pl>

hi everyone,

Our workshop starts at 14:00 tomorrow:

  Fri 16 March: Boud On the topological implications of inhomogeneity
  http://arXiv.org/abs/1201.5845

Discussion on the paper itself will be followed by discussion of
the software project that several of us discussed last week. It's not
yet public, so i'll leave it unnamed :).

A warm-up exercise for the workshop would be to check your intuition
of S^3 - use the analogies between S^2 \subset R^3 and S^3 \subset R^4.

[BTW, sorry if some people missed the word "tentative" in my 5 March
email - "tentative" means "possible, but waiting confirmation".]

pozdr
boud