Shape-univ October 2003

shape-univ@cosmo.torun.pl

5 participants
7 discussions

pamietamy: wyklad monog dzis *w sal komputerze KA&A* !!!
by Boud Roukema 30 Oct '03

30 Oct '03

witam, pamietamy: wykład monog dziś 30.10.2003 *w sal komputerze KA&A* na 15.15 pozd boud http://adjani.astro.uni.torun.pl/cgi-bin/twiki/view/Cosmo/MonographCosmo

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nastepny wyklad monograficzny czwartek 30.10.2003 (nie jutro!)
by Boud Roukema 22 Oct '03

22 Oct '03

http://adjani.astro.uni.torun.pl/cgi-bin/twiki/view/Cosmo/MonographCosmo jest seminar (cafeplus) jutro, ale nie ma wyklad monograficzny. pozd boud

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regards
by Alhaja Mariam Abacha 22 Oct '03

22 Oct '03

Dear friend, A very Good day to you.I am by name,Alhaja mariam sani Abacha,the former firstlady and also the wife of the former late head of state of the federal republic of Nigeria,Late Gen.Sani Abacha whose sudden death came on the 8th of June,1998.Since his death,I have been thrown into a state of utter confusion, frustration and hopelessness by the present civilian administration, I have been subjected tophysical and psychological torture by the security agents in the country. My son Mohammed was under detention arraigned before the federal high court of Nigeria for an offence he did not commit.Though he has been released since on the 23rd of september,2002 based on certain conditions,but he is not allowed to move around to any where.He has been restricted to his own town only and also been placed under the government watch.As a widow that is so traumatized, I have lost confidence with anybody within the country. You must have heard over the media reports and the internet on the recovery of various huge sums of money deposited by my husband in different security firms abroad, some companies willingly gave up their secrets and disclosed our money confidently lodged there while many out right blackmail. In fact the total sum discovered by the government so far is in the tune of$700.Million dollars. And they are not relenting to make me poor for life. I got your contacts through my personal research,and out of desperation decided to reach you through this medium.I will give you more information as to this regard as soon as you reply. I repose great confidence in you hence my approach to you dueto security network placed on my day to day affairs I cannot afford to visit the embassy so that is why I decided to contact you and I hope you will not betray my confidence in you. I have deposited the sum of $30 million dollars with a security firm abroad whose name is witheld for now until we open communication. I shall be grateful if you could receive this fund into your account for safe keeping. This arrangement is known to you and my son Abba alone, so my son will deal directly with you as security is up my wholebeing.I am seriously considering to settle down abroad in a friendly atmosphere like yours as soon as this fund get into your account so that I can start all over again if only you wish,but if it is impossible,just help me keep this funds in your account which will accrue you 30% of this fund . Please honesty is the watch word in this transaction.I will require your telephone and fax numbers so that we can commence communication immediately and I will give you a more detail picture of things.In case you don`t accept please do not let me out to the security as I am giving ou this information in total trust and confidence, I ill greatly appreciate if you accept my proposal in good faith.Please expedite action. Sincerely yours, Alhaja Mariam Abacha.

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nowy dzien/godzin wyklad monogr: pon. 16.10-17.40
by Boud Roukema 18 Oct '03

18 Oct '03

Witam, Czwartek była propozycja nowa dzień/godz wykład monograficzne: każdy poniedziałek 16.10-17.40 Proszę zobacz: http://adjani.astro.uni.torun.pl/cgi-bin/twiki/view/Cosmo/MonographCosmo pozd boud

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Re: Dodecahedral space topology
by Boud Roukema 10 Oct '03

10 Oct '03

here's the full article: http://arxiv.org/abs/astro-ph/0310253 On Thu, 9 Oct 2003, Boud Roukema wrote: > On Thu, 9 Oct 2003, Andrzej Marecki wrote: > > > ----- Forwarded message from NatureAlert ----- > > > > [...] > > > > Dodecahedral space topology as an explanation for weak wide-angle > > temperature correlations in the cosmic microwave background > > JEAN-PIERRE LUMINET, JEFFREY R. WEEKS, ALAIN RIAZUELO, ROLAND LEHOUCQ > > & JEAN-PHILIPPE UZAN > > http://info.nature.com/cgi-bin24/DM/y/eMJG0BfWLH0Ch0EeW0Ay >

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l_p ~ \Omega_tot^-1/2
by szajtan odwieczny 08 Oct '03

08 Oct '03

for those who are not in the topic it is about the question why is l_p (which is the number of the multipole on which there is the first peak - so called acustic peak - in the angular power spectrum of CMB fluctuations) proportional to \Omega_tot^-1/2 (which is the unitless total density of the Universe) ? Lately I was thinking about such explanation but don't know if this mae be correct. l_p \approx EH_LSS / SH_LSS where EH_LSS is (say *) the event horizon at the time of last scattering and SH_LSS is the sonic horizon at the last scattering (t=t_LSS). EH_LSS = c * \int_{t_LSS}^{t_0} dt/S(t) SH_LSS = c_s * \int_{0}^{t_LSS} dt/S(t) where c - speed of light, c_s - speed of sound, S(t) - is scale factor. So it's just the angle under which today we see the sonic horizon as it was at the time of last scattering. so from the above it would be that: l_p ~ c_s^-1 (~ means "proportional" here) the speed of sound is defined by: c_s = \sqrt{ (P/\rho)_S } (while entropy - S is constant) (P- pressure, \rho - density) for adiabatic transformation the entropy is or mae be conserved and the equation of state is: P\rho^-\gamma = const where \gamma is the adiabatic index So in short we have c_s ~ \rho^{ (\gamma - 1)/2 } and thus l_p ~ \rho^{ (1-\gamma)/2 } ~ \Omega_{tot}^{ (1-\gamma)/2 } so if the adiabatic index gamma for primordinal plasma is 2 then this consideration mae answer the quiestion, however gamma for nonrelatistic, in moderate temperatures, single-atom gases is something like 1.67 - not 2. Don't know how it is with hydrogen plasma in temperature of few thousand K. Any comments much appreciated. like it might be ok. or this is complete nonsense. ------------ Boud: * - this is the comment about the event horizon. sure that the event horizon is the maximal distance from which, say some light, will ever reach us - and because of that I agree there should be infinity in the top limit of integration in the above formula for event horizon, but I guess if it comes about the event horizon at the time t=t_LSS then wheather there is \infty or just t=t_0 doesn't change the integral much, because from the t=t_LSS point of view the time like 14,2*10^9 y is like infinity. (Because the cones of light of some simultanous events at the time t_LSS drown in "normal" (proper ?) coordinates (not comoving) which are separated (the events) by the distance of event hirizon at the time t=t_LSS, become almost paralel.**) So in other words the size of the event horizon given by the above formula will probably be just a little smaller than the real event horizon at the time in case when integrated to infinity. bart. ----- btw. It is interesting that: If calculate l_p for dust universe where S(t) ~ t^2/3 it is easy to show that l_p \approx 35,2 * c/c_s and thus for l_p=220 where it is observed, we see that at the time of last scattering the sound of speed was about 6,25 times smaller than the speed of light which sounds resonable ;) (oh, this is for flat univ.) ** - this requires some more work to think, and mae be not precise explanation.

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Shape of the Universe IV+V rok monograph course 15:15 today !
by Boud Roukema 02 Oct '03

02 Oct '03

Cześć wszystkim, The teaching responsibilities that Andrzej Strobel offered to me are presented here: http://adjani.astro.uni.torun.pl/cgi-bin/twiki/view/Cosmo/CosmoTeaching2003… ** Monograph course: It seems that the IV+V monograph course officially starts today (czwartek 02.10.2003) at 15:15 in the Radio building. Anyone interested please come along today and/or subscribe to the shape-univ mailing list: SUBSCRIBE: email to sympa(a)astro.uni.torun.pl with "subscribe shape-univ" ** "IV+V Seminar": This is compatible with CafePlus, but 17:00 czwartek is clearly not the best time. Day/time: You can join the cosmo-spotka mailing list for trying to find the best day/time for this. Place: It would be best to alternate between Piwnice (radio building) and CAMK (rabiańska). SUBSCRIBE: email to sympa(a)astro.uni.torun.pl with "subscribe cosmo-spotka" Proszę odpowiedź do: cosmo-spotka at astro.uni.torun.pl pozdrawiam boud

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Shape-univ October 2003