Cosmo-torun

cosmo-torun@cosmo.torun.pl

328 discussions

cosmo workshop Fri 15:00 12.03.2010: Li and Liu arXiv:1003.1073: WMAP quadrupole = antenna direction interpolation error
by Boud Roukema 02 Aug '10

02 Aug '10

witam cosmo-torun Cosmo workshop WHEN: Fri 15:00 12.03.2010 WHO: boud TITLE: Liu and Li arXiv:1003.1073 ("The origin of the WMAP quadrupole") ABSTRACT: The WMAP quadrupole is apparently mostly a pointing error. The true quadrupole is much closer to zero. The missing fluctuations problem has just got much worse for the infinite-flat-universe hypothesis. Liu and Li arXiv:1003.1073 ("The origin of the WMAP quadrupole") have posted a very interesting article (presumably submitted to Nature, guessing from the style and length). The best estimate of the CMB quadrupole is apparently... zero! They claim that the WMAP quadrupole comes from a single error - an antenna direction representation error by half of an observational angular interval. The discussion concerns quaternions, but don't be frightened - it presumably uses the imaginary part only, to represent X, Y, Z directions. You can think of them as vectors in R^3 if you like. Order of magnitude check of their calculation: Liu and Li say that the error is by 7' and that this causes incorrect subtraction of the dipole in the time-ordered-date (TOD). The direction of the error varies as the direction of observation varies, so it's reasonable that it doesn't give a simple offset detectable by post-processing in the analysis pipeline, IMHO (though Bartek may have another opinion). The dipole is about 3.3mK (e.g. section 7 Bennett et al 2003). sin(7') * 3.3mK = 0.002 * 3.3mK = 6.7 microK Liu and Li say 10-20 microK, just slightly higher, but their Eq.(1) is a motivational equation - it is not used as an entry to their data analysis pipeline. Figures 1 and 2 should the effect very dramatically. Rephrasing what they've said: Figure 1 left: difference between Liu Li analysis, using the same wrong method that the WMAP team used. This is a check that their pipeline does the same thing that the WMAP team does. |Difference| < 2 or so microK. Figure 1 right: Liu Li using correct antenna directions on WMAP Q1 3yr data. They get a strong quadrupole! Figure 2 left: The effect of using a wrong dipole, calculated using *only the directional information* from the time-ordered-data from the spacecraft, with *no CMB data*. See paragraph 2, page 4: "only the spacecraft attitude information is used to compute d' ." Figure 2 right: official WMAP5 V+W quadrupole. Figures 1 right, and 2 left look very, very similar to Figure 2 right. There seems to be a slight difference in angular position visible by eye, but the coincidence is striking. Can we really believe that the CMB quadrupole just by chance happens to be very strongly aligned with and of nearly identical amplitude to a map made using only the time-ordered-data of the spacecraft direction ("attitude") and the spacecraft orbit around the Sun, and the Sun's motion with respect to the CMB? Since this is a Nature-type article, the authors are forced to exclude almost all interesting details from the article, but info like the spacecraft attitude quaternions and interpolation method should not be too difficult to find. * Bennett et al 2003: arXiv:astro-ph/0302207 http://arXiv.org/abs/astro-ph/0302207 * Liu, Li 2010: arXiv:1003.1073 http://arXiv.org/abs/1003.1073 The good thing about this is that it shows that a lot of very intelligent people - those in a mega-collaboration plus many outside of the official group - can spend 7 years looking closely at an important set of observational data without finding what appears to be a very elementary error in the analysis details, with a very fundamental consequence. The fundamental consequence is that a lower quadrupole makes Infeld's (1949) prediction of the equivalent of the low l cutoff due to the shape of the Universe even stronger! Liu & Li suggest an inflationary argument, but their interpretation is not what is important - they don't want the referee to make a fuss about interpretations, since their observational argument is so strong. pozdr boud

1 2

cosmo wiki workshop tomorrow Fri 15.00! let's reorganise our wiki...
by Boud Roukema 01 Jul '10

01 Jul '10

hi everyone, Fri 2 July 15.00 @KRA - cosmo wiki workshop let's reorganise the wiki: http://cosmo.torun.pl/cosmo/ and the home page http://adjani.astro.uni.torun.pl Bartek has done a nice job of setting up a draft of the new KRA web pages, with a nice link to the cosmology pages. So now it's time for the rest of us (starting with me!) to help do some reorganisation. i'll start today, and i propose that we (finally) get back to our workshops by starting with a wiki workshop tomorrow. My idea is that probably i will do the "main" editing, with the pages shown in the projector, so that we can have a general discussion what should go where, while i edit. But if other people bring laptops, then they can also edit (e.g. other pages) and/or take over the use of the projector and we'll see if we can converge by using both wiki + face-to-face communication. i'll see if we can get hold of a switch (should be doable) so that if more people bring along laptops, then we can together do some reorganisation. By the nature of wiki, this means that some of the editing can be done in parallel. pozdr boud

1 0

cosmo meetings northern summer 2010
by Boud Roukema 15 Jun '10

15 Jun '10

Witam cosmo-torun, As usual, there are many cosmo meetings in Europe this northern summer. :) This is slightly edited from two French cosmo/extragalactic mailing lists messages. pozdr boud > ---------- Forwarded message ---------- > Date: Mon, 29 Mar 2010 09:36:20 +0200 > Subject: Diffusion PNCG - mess n° 23 (fwd) > Date: Wed, 19 May 2010 18:59:46 +0200 > Subject: Diffusion PNCG - mess n° 25 1. X?me école de cosmologie 5 - 10 July 2010 in Cargese, Corsica http://www.cpt.univ-mrs.fr/~cosmo/EC2010/EcoleLuminy10.html 2. symposium ?Fundamental Frontiers of Physics" 6 to 9 July, 2010, Paris http://ffp11.gie.im 3. The 14th Paris Cosmology Colloquium 2010 - Chalonge Thursday 22, Friday 23 and Saturday 24 JULY 2010 http://chalonge.obspm.fr/colloque2010.html 4. 35th International Conference on High Energy Physics 22 - 28 July, Paris. http://www.ichep2010.fr/ 5. 8th International Conference on Identification of Dark Matter Montpellier, July 26-30th 2010. http://www.lpta.univ-montp2.fr/idm2010 6. New Directions in Modern Cosmology from 27 Sep 2010 through 1 Oct 2010 http://www.lc.leidenuniv.nl/lc/web/2010/412/info.php3?wsid=412 ----------------------------------------------------------------------- 1. X?me école de cosmologie Nous avons le plaisir de vous annoncer la tenue de la dixi?me école de cosmologie intitulée "Le fond diffus cosmologique ? haute résolution angulaire". Elle se déroulera la semaine du 5 au 10 juillet 2010 ? l'IESC (Carg?se). Avec le lancement réussi du satellite Planck, une nouvelle fen?tre d'?observation s?ouvre en cosmologie. L'objectif scientifique de cette école est de montrer comment cette nouvelle génération de données va permettre la recherche de signatures nouvelles caractérisant les mod?les d'univers primordial. Il ne s?agira pas de traiter les données de Planck, qui ne seront pas publiques ? cette époque, mais d?'explorer les avancés théoriques et phénoménologiques. On présentera la physique du fond diffus cosmologique, en insistant en particulier sur les aspects nouveaux, les plus pertinents pour la confrontation des théories aux observations. Les cours principaux seront assurés par N. Aghanim (IAS) - J.F. Cardoso (LTCI) - A.Challinor (DAMTP) - P. Creminelli (ICTP) - E. Komatsu (TCC) - J. Lesgourgues (LAPTH) - S. Prunet (IAP) - J.-P. Uzan (IAP). Ils seront enrichis par des séminaires/cours annexes, des discussions et des débats contradictoires. siteweb : http://www.cpt.univ-mrs.fr/~cosmo/EC2010/EcoleLuminy10.html NB : Le nombre de places étant limité, les intéressés sont priés de s'y inscrire au plus vite pour que l'on puisse prévoir une logistique adéquate. Les organisateurs F. Bernardeau (CEA/DSM/IPhT) - R. Triay (CPT) - F. Vernizzi (CEA/DSM/IPhT) ----------------------------------------------------------------------- 2. symposium ?Fundamental Frontiers of Physics" The 11th annual international meeting ?Fundamental Frontiers of Physics? will take place in Paris, France from 6 to 9 July, 2010. The deadline for submission of an abstract is the 15th of June and for early registration to ?Fundamental Frontiers of Physics? is the 25th of June, 2010. The Symposium develops around five themes: 1. Big Bang Cosmology / Dark Energy 2. Dark Matter/Astroparticles 3. Particle physics and Fundamental Interactions 4. From Intrication to Quantum Information and Quantum Gas 5. Epistemology, History of Physics Parallel sessions will be organized as mini-workshops consisting mostly of twenty minutes oral presentations. Scientific Committee A. Aspect, Institut d?Optique (Palaiseau) P. Binétruy, APC, Paris Diderot University E. Brezin, ENS (Paris) F. Combes, LERMA (Obs. Paris) J. Iliopoulos, ENS ( Paris) J. Kouneiher, University of Nice/IUFM and LUTH (Obs. Paris) M. Lachi?ze-Rey, APC, Paris Diderot University J. A. Madore, University of Orsay J.-J. Szczeciniarz, HPS, Paris Diderot University Please visit the website of the conference for all relevant information http://ffp11.gie.im ----------------------------------------------------------------------- 3. The 14th Paris Cosmology Colloquium 2010 Ecole Internationale d'Astrophysique Daniel Chalonge THE STANDARD MODEL OF THE UNIVERSE: THEORY AND OBSERVATIONS George Smoot Nobel Prize of Physics and Daniel Chalonge Medal Thursday 22, Friday 23 and Saturday 24 JULY 2010 at the parisian campus of Paris Observatory (HQ), in the historic Perrault building. The Conference is within the astrofundamental physics spirit of the Chalonge School, on recent observational and theoretical progress on the CMB, Inflation, astrophysical dark matter, dark ages, dark energy, and the theory of the early universe with predictive power. In summary, the aim of the meeting is to put together real cosmological data and hard theory predictive approach connected to them in the framework of the Standard Model of the Universe. Topics: Observational and theoretical progress in the CMB, astrophysical dark matter, dark energy, dark ages . Large and small scale structure formation. Inflation in connection with the CMB and LSS data, slow roll and fast roll inflation, quadrupole suppression and initial conditions, low CMB multipoles. CMB polarization. Neutrinos in cosmology. The Meeting is open to all scientists interested in the subject. All Informations about the meeting and registration to it are displayed at : http://chalonge.obspm.fr/colloque2010.html Early Registration is strongly encouraged The format of the Meeting is intended to allow easy and fruitful mutual contact and communication. Sessions last for three full days in the beautiful parisian campus of Observatoire de Paris (built on orders from Colbert and to plans by Claude Perrault from 1667 to 1672). All sessions take place in the historic Perrault building ("Bâtiment Perrault") of Observatoire de Paris HQ, under the portraits of Laplace, Le Verrier, Lalande, Arago, Delambre and Louis XIV. An exhibition will retrace the 19 years of activity of the Chalonge School and George Smoot participation to the School along these 19 years. Informations on the previous Paris Cosmology Colloquia and of the school events are available athttp://chalonge.obspm.fr (lecturers, lists of participants, lecture pdf files and photos during the Colloquia). Chalonge.Ecole(a)obspm.fr http://chalonge.obspm.fr/ ----------------------------------------------------------------------- 4. 35th International Conference on High Energy Physics La 35?me Conférence Internationale de Physique des Hautes Energies, la plus importante au monde dans cette spécialité, aura lieu cet été en France, du 22 au 28 juillet ? Paris. A noter que les astroparticules et la cosmologie y seront largement représentées dans une session dédiée et dans les exposés pléniers. Site web : http://www.ichep2010.fr/ ----------------------------------------------------------------------- ----------------------------------------------------------------------- 5. 8th International Conference on Identification of Dark Matter This is the second circular announcing the *** 8th International Conference on Identification of Dark Matter *** that will be held in Montpellier, July 26-30th 2010. We are glad to announce that we will extend abstract submission until MAY 30th 2010 Please refer to http://www.lpta.univ-montp2.fr/idm2010 for further information on travel and accommodation, registration, payments, and abstract submission. See also at the end of this email. We encourage abstract submission from graduate students and posdoctoral fellows. We would appreciate if you could bring this announcement to their attention, and diffuse it to your scientific communities and research departments. Looking forward to seeing you in Montpellier, The local organizing committee Please feel free to contact us if you have questions regarding IDM 2010 (idm2010com(a)lpta.univ-montp2.fr). ----------------------------------------------------------------------- 6. New Directions in Modern Cosmology New Directions in Modern Cosmology from 27 Sep 2010 through 1 Oct 2010 Scientific organizers: T.M. Nieuwenhuizen, ITFA, UvA, R.E. Schild, Harvard CfA F. Sylos Labini, Enrico Fermi Center, Rome R. Durrer, Univ Geneva Aim and description This workshop concentrates on the discussion of recent cosmological observations which present challenges to the standard LCDM model. These observations include: the large scale flows, the sizes and amplitude of galaxy large scale structures, the systematic effects biasing the analysis of CMB data and the lack of large-angle correlations, the anisotropy of the Hubble flow, the evolution of galaxy size, and the failure to find the sub-halo building blocks left over from the primordial fluctuation spectrum. Last and not least, it is disturbing that in the LCDM model 95% of the Universe have not been observed 'directly'. While each of these observations can be seen as an anomaly that the model would possibly explain, the bulk of them calls for a more careful analysis of the model foundations, particularly the amount and role of dark substances. From the theoretical side it is known that the role of hydrodynamics can be more important that often assumed. Moreover recently there has been a considerable theoretical effort to develop a coherent picture in General Relativity which appropriately takes into account matter inhomogeneities. By connecting and discussing different approaches and results, this workshop, aims to advance our comprehension of the large scale universe. Progress can be hoped for by combining insights from various groups of researchers studying different observational and theoretical problems. The workshop offers a unique opportunity to discuss conceptual and methodological problems of the present cosmological paradigm. Central questions are posed from observational and theoretical perspectives: - Galaxy Structures on large scales: How large are galaxy fluctuations on 100 Mpc/h scale? Do we see the predicted anti-correlations in the two-point correlation function? - Is there a systematic problem in the CMB large angle correlations? Is there true evidence for a galaxy-CMB cross correlation? - Are large scale flows at odds with LCDM predictions? - What is the role of joint effects of gravity and hydrodynamics in the theory of structure formation? - What is the role of large density inhomogeneities in General Relativity? Which effects can be observed? We of course cannot expect to obtain answers to any of those questions during this workshop but we can discover how expertise from different fields can be combined to fruitfully address them. The diversity in the background of the participants guarantees that new questions will arise and new approaches will be formulated. The central role of the workshop will be to stimulate and coordinate this interaction. http://www.lc.leidenuniv.nl/lc/web/2010/412/info.php3?wsid=412 -----------------------------------------------------------------------

1 0

advanced summer school on computational astrophysics at Nicolaus Copernicus University, Torun, Poland, 11-25 July 2010
by Boud Roukema 08 Mar '10

08 Mar '10

witam cosmo-torun Our colleagues in the optical group have got together with some galaxy formation people and are organising a simulation workshop this northern summer (July 2010): http://supercomputing.astri.umk.pl/ Ben Moore is one of the key people doing galaxy simulational work since a long time ago. Romain Teyssier does adaptive tree code work AFAIK - his program RAMSES is here: http://irfu.cea.fr/Projets/Site_ramses/RAMSES.html It is wolne oprogramowanie, under the CECILL licence, which is GPL-compatible under section 5.3.4 of the CECILL licence: http://www.cecill.info/licences/Licence_CeCILL_V2-fr.txt i think that many of us could be interested in participating or at least listening to a few talks. i'm sure that Michal Hanasz and the doktoranci will tell us if they prefer us to formally register or not, though of course, i'm sure there wouldn't be things like registration fees for local participants. We should think of organisers' practical side of making sure that there are enough seats or computers available, etc. but i don't expect that that would be a huge problem - e.g. eduroam access for laptops should presumably be available at the Maths building. pozdr boud

1 0

two books for library: Schilpp/Infeld (1949); Bolejko et al (2009)
by Boud Roukema 04 Mar '10

04 Mar '10

hi Karolina, Here are two books that would be useful to buy. The first one has what seems to be the first statement of the "nothing-can-be-bigger-than-the-Universe" argument in terms of density perturbations. Apparently, the first scientist(s) to state the argument were not Starobinsky (1993) and Stevens et al (1993), but rather... a Polish physicist: Leopold Infeld in 1949! The second book synthesises recent papers on the Einstein-equation exact-solution approach to what i have repeatedly said in our cosmology group several times (and Helena is working on this :). In simple words: "the simplest explanation for dark energy may be the failure to do the maths carefully enough". (1) Albert Einstein: philosopher-scientist, edited by Paul Arthur Schilpp , 1949 (republished 1970) e.g. http://searchworks.stanford.edu/view/1066168 http://www.questia.com/library/book/albert-einstein-philosopher-scientist-b… (2) Bolejko et al 2009: Title: Structures in the Universe by Exact Methods Author: Krzysztof Bolejko, Andrzej Krasinski, Charles Hellaby, Marie-Noelle Celerier ISBN: 9780521769143 http://assets.cambridge.org/assets/bookpageresult.jsf?conversationId=1165892 The first book is apparently cheap, the second one expensive. Both would be useful IMHO. pozdr boud

1 0

(1) workshop 15.00 Fri 20.11.2009 - another way to select comoving 3-space; (2) Festiwal 2010
by Boud Roukema 21 Jan '10

21 Jan '10

witam cosmo-torun (1) Research workshop! title: Another way to select comoving 3-space speaker: boud when/where: Friday 15.00 godz. 20.11.2009 @KRA. This topic will be different to my Monday KRA seminar. My Monday talk is about stuff on ArXiv.org and already peer-reviewed. Friday is for research-under-progress presentation/discussion - that's the idea, after all. (2) We have to announce FNiS2010 (science festival) proposals by Monday 23 Nov!!! Anyone interested in us doing something together, please speak up quickly, and we can briefly discuss it on Friday face-to-face (or tomorrow Thurs @KRA). Here's my proposal for what i'd like to talk about: http://cosmo.torun.pl/Cosmo/FestiwalNauki2010 pozdr boud

1 2

Fwd: cosmo workshop Mike Peel - SZ sky simulations 15.00 Fri 15 Jan
by Bartosz Lew 13 Jan '10

13 Jan '10

Hi all, This is just a forward of the announcement also to Mike. I thinks it's very useful for students to see what is currently going on in CMB, Sunyaev-Zeldovich, radio point sources science - how to simulate realistic maps including these effects etc. This is gonna be a workshop type talk so every questions are welcome ! -- ================================================ Bartosz Lew Nicolaus Copernicus University, Torun Centre for Astronomy, Department of Radio Astronomy tel: +48 (56) 611 3042 email:blew@astro.uni.torun.pl, www: http://cosmos.astro.uni.torun.pl/~blew

1 0

cosmo workshop Mike Peel - SZ sky simulations 15.00 Fri 15 Jan
by Boud Roukema 13 Jan '10

13 Jan '10

Witam This week we have a guest from Jodrell Bank for our cosmo workshop :). WHAT: SZ sky simulations WHEN: 15.00 Fri 15 Jan 2010 WHERE: KRA WHO: Mike Peel pozdr boud

1 0

14.45 godz piatek 8 stycznia 2010, Lew@KRA: CMB cold spot; Planck first light
by Boud Roukema 07 Jan '10

07 Jan '10

hi cosmo-torun Cosmo workshop tomorrow Fri 8 Jan 2010 - a cold spot talk is just what we need in this weather... :P WHEN/WHO/WHERE: 14:45-15:45 Bartek Lew KRA WHAT: A study of the galaxy redshift distribution toward the cosmic microwave background cold spot in the Corona Borealis supercluster Genova-Santos et al. 2010 http://arxiv.org/abs/0912.5167 If there's time, i'll mention (maybe just briefly, at least) the lack of low l power in the Planck First Light publicity image: http://cosmocoffee.info/viewtopic.php?t=1479 http://arxiv.org/abs/0910.5102 Cover http://arxiv.org/abs/0911.4063 Liu & Li pozdr boud

1 0

Moriond 2010 Cosmology (fwd)
by Boud Roukema 28 Dec '09

28 Dec '09

Moriond 2010 Cosmology Dear colleague, The next Rencontres de Moriond meeting devoted to Cosmology will be organized in La Thuile (Valle d'Aosta, Italy), March 13-20, 2008. Registration is open on http://moriond.in2p3.fr/J10/ where more details can be found (including abstract submission) The main topics covered in the conference are summarized at the end of this message looking forward to welcom you in La Thuile, with our best regards, the organizing committee ------- 1. Clusters / SZ effect Cosmology with clusters Optical detection and self calibration methods X-ray clusters Hydrodynamical simulations SZ Clusters Radio galaxies clusters 2. CMB / Polarization WMAP Planck Polarization measurements 3. Reionization / Radio Numerical simulations LOFAR: foregrounds GMRT Other projects (MWA ...) 4. Dark Energy / Dark Matter SNLS BAO / SDSS Weak lensing Cluster Mass Profile 5. Dark Matter: accelerator searches Direct search at the LHC Direct search with underground detectors Indirect seraches (Fermi / Gamma-ray astronomy) 6. Theory Modified gravity Dark energy models Primordial universe / Inflation 7. Herschel Herschel Science Demonstration Phase Initial Results --

1 0

← Newer
1
2
3
4
5
6
7
8
9
...
33
Older →

Jump to page:

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

Cosmo-torun