Shape-univ February 2003

shape-univ@cosmo.torun.pl

6 participants
3 discussions

Re: new cmb code... (fwd)
by szajtan 17 Mar '03

17 Mar '03

ok. ciakawa koncepcja ale nie do konca rozumiem jak to dziala. masz obliczona i zparametryzowana (parametrami) w jakis sposob siatke modeli (o roznych parametrach kosmologicznych). tak ze na podstawie zadanych wartosci parametrow (nie kosmolog.) mozna szybko odtworzyc widmo. poszukiwane widmo w n wymiarowej przestrzeni parametrow jest otoczone przez 2^n modeli bazowych (o znanych zestawach wartosci parametrow kosmologicznych, i tych z parametryzacji). Mozna tez obliczyc jak daleko w przestrzeni parametrow kosmologicznych lezy poszukiwany model od modelow budujacych wezly siatki (tylko jak z tego skorzystac). Wiemy rowniez o ile roznia sie miedzy soba zestawy wartosci parametrow przypisanych do wezlow sieci. Ale nie chwytam kewstii obliczenia poszukiwanych wartosci parametrow na podstawie ktorych mozna odtworzyc widmo. Czyli innymi slowy jak to interpolowac skoro wiemy tylko ze poszukiwany zestaw parametrow lezy gdzies w oczku siatki parametrow.? > I have the code - not publicly available yet, but soon > it works as follows: > > 1. grid is produced and in nodes exact (well... cmbfast) cl spectrum is > calculated > 2. for every node some parametrisation of the spectrum is done (scaling, > chebyshev coeficients etc.) > 3. for given cosmo parms those parameters are interpolated and the > spectrum is reconstructed. > > quite simple. but faster than other interpolation methods (for gridded > models). > that is the main idea... > > polarisation also possible, but not yet implemented. > I can send you the code with the spectrum database if you wish. > > Bartosz Lew wrote: > > >ok, what's the catch ? > >and where is the code ? > > > >and btw. how this works ? > > > >On Mon, 17 Feb 2003, Michal Frackowiak wrote: > > > > > > > >>well, not completed, not even documented, but if anyone of you would > >>like to use it to reconstruct cmb spectrum REALLY FAST (within > >>miliseconds) - please try. > >>http://coyote.ncac.torun.pl/~michalf/cmbrecon/cmbrecon.php > >> > >>well - you can treat it as a preview of what is really about to happen. > >>a fast cmb-spectrum reconstruction code. with quintessence (or whatever) > >>included (soon also other scalar-tensor things). for generating grid: > >>server-client architecture, quite smart reconstruction algorithms.... > >>in case of interest/doubts/will to use - feel free to contact me. code > >>is quite complete and usable. > >> > >>michal frackowiak > >> > >> > >> > >> > >> > > > > > > > >------------------------------------------------------------------------ > > > >LISTNAME: shape-univ > >HELP: send an email to sympa(a)astro.uni.torun.pl with "help" > >WEB ARCHIVE: http://www.astro.uni.torun.pl/sympa/shape-univ/ > >UNSUBSCRIBE: email to sympa(a)astro.uni.torun.pl with "unsubscribe shape-univ" > > > > > > > > > > > > ---------------------------------------------------------------------------- ---- LISTNAME: shape-univ HELP: send an email to sympa(a)astro.uni.torun.pl with "help" WEB ARCHIVE: http://www.astro.uni.torun.pl/sympa/shape-univ/ UNSUBSCRIBE: email to sympa(a)astro.uni.torun.pl with "unsubscribe shape-univ" --------------r-e-k-l-a-m-a----------------- Tanie bilety lotnicze! http://samoloty.onet.pl

5 11

about the variability
by Bartosz Lew 20 Feb '03

20 Feb '03

I was inspired by Magda's seminar this monday about the variability of css, gps or whatever. She said that variability is something like a hundret years. And then I thought: shouldn't it (the period) be corrected for the expansion of the universe since these objects happend to be so strongly redshifted ? Or maeybe this effect is negligible. bartek

3 4

Fwd: The Oldest Light in the Universe
by Tomasz Laczkowski 12 Feb '03

12 Feb '03

NASA Science News for February 11, 2003 A NASA satellite has taken a picture of the Big Bang's ancient afterglow. Scientists have analyzed the data and learned that the universe is 13.7 billon years old (plus or minus 1 percent)and that the first stars appeared only 200 million years after the Big Bang. These results are a milestone in cosmology, says the NASA director of astronomy and physics. FULL STORY at http://science.nasa.gov/headlines/y2003/11feb_map.htm?list129344 <czosnek> \|/ (|||) " -

1 0

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

Shape-univ February 2003