Cosmo-torun

cosmo-torun@cosmo.torun.pl

328 discussions

GNC meeting 2024
by Mariana Jaber 25 Mar '24

25 Mar '24

Apologies if you receive this multiple times. ---- I'd like to bring your attention to the conference organized by the University of Szczecin, in Poland. This meeting will focus on astrophysics research supporting various domains, including astroparticle (gamma-ray and cosmic-ray), X-ray, gravitational- waves, observational cosmology, exoplanet, and stellar astrophysics. There is no registration fee, and the meeting will be both in person and online. For further details, please visit the following link: https://gnc2024.physics.muni.cz/ The link for registration: https://gnc2024.physics.muni.cz/register.html ----

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Re: [Cosmo-torun] IAU B1 Newsletter No.6 Aug. 11, 2020
by Boud Roukema 15 Aug '20

15 Aug '20

Dear Dmitry, On Tue, 11 Aug 2020, Dmitry Bisikalo wrote: > With this letter, we kindly ask for your view on the format this > meeting should take and how it should be organized. Specifically, we > ask you to answer the following questions. You have omitted the most important question: 0. What practical and ethical guidelines do you recommend for (i) the software and (ii) the hosting services to use for the online meeting? Could you please send this question to Commission B1 members? Thank you in advance. My answers are below. > 1. Would you be interested in participating in such a meeting and in > giving a talk? If yes, please, provide a (very preliminary) title of > your presentation. Tentatively, yes: "A galaxy formation software pipeline aiming at full reproducibility on any POSIX-compatible operating system" > 2. Which way of giving a talk would be more suitable for you, live > presentations or pre-recorded ones? I see little point in pre-recorded presentations - conferences are most useful for their interactive aspects. > Should we include only short contributed talks in the program or > will some more extended review talks also be helpful? I think that reviews should be proposed as drafts on any git repository satisfying IAU ethical guidelines. (Repositories that forbid access to scientists based on their nationality or geographical location are disqualified under IAU anti-discrimination guidelines; this disqualifies github and bitbucket.) > 3. Should we plan a special session limited to topical discussions? > Can you suggest some issues to be discussed at the session? A topical discussion on reproducibility, free licensing and long-term sustainable astronomy software development would be very useful. Too many astronomers choose "direct action" - we publish software on a git repository with a fuzzy licence (or an absent licence, i.e. the Berne convention, which forbids copying, modification and redistribution) and ignore the question of long-term integration of astronomy software into the wider free-software and open-source-definition-software (FOSS) environment. Question 0 for Commission B1 members: What practical and ethical guidelines do you recommend for (i) the software and (ii) the hosting services to use for the online meeting? 0.(i) The conferencing software must be free-licensed, with a licence satisfying either the free software definition or the open source definition. The software must use open protocols that are compatible with free-software licences and that do not restrict astronomers to any particular vendors (corporations or citizens' associations or individual hosters). Practical videoconferencing possibilities include bigbluebutton (bbb), jitsi, jami [1], the matrix protocol (with a front end such as element.io) [2], and irc (well-tested over many decades and highly efficient). 0.(ii) The hosting services should (1) allow the astronomers using the service to install the conferencing software on their own servers, e.g. at their research institute; (2) allow wide interoperability with equivalent services; (3) allow easy and practical export of the astronomers' stored data from that particular service; (4) must not require the astronomer to install any unverifiable (e.g. binary) software on his/her computer. These reasons are all practical rather than ethical. Criteria (i) + (ii) imply that Zoom and Slack are excluded, because they violate most of the practical constraints (1)-(4). Moreover, the ethical violation with using Zoom or Slack (or MS Teams or an equivalent Google service) is that "the astronomer is the product to be sold to advertisers". Astronomy, especially in the context of the IAU, is meant to be an inspiration and example to the world. We should not give the wider public the bad example of humans becoming products to be sold to advertisers. For more details on bbb/jitsi/jami/matrix, see [1] https://switching.software/replace/zoom [2] https://switching.software/replace/slack For more details on the overall answers and the IAU's practical and ethical considerations to take into account for question 0, see [3] https://cosmo.torun.pl/blog/slack_zoom_prison . > Since we believe that a preference should be given to young > scientists (PHD students, young PHDs within three years after the > defense), we would be grateful if you spread this information among > young researchers in your home institution. The easiest way to do this is with a conventional mailing list, so I'm cc-ing this answer to our local publicly archived mailing list. I see nothing private in your questions, and after all, the IAU is a network of citizens' associations, so we really should be shifting to fully public, transparent, rational discussion. Commission B1 - Computational Astrophysics [4] - has even less justification for secrecy than any other part of the IAU! :) > We will be grateful to receive your responses by 1st September, > 2020. And do not forget that the IAU Symposium 362 is not cancelled > but just postponed till June 2021! > Yours sincerely, > Members of the IAU Commission B1 Organizing Committee Regards Boud [4] https://www.iau.org/science/scientific_bodies/commissions/B1/

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A possible crisis for cosmology - Cosmology Journal Club 18/11
by Matteo Cinus 14 Nov '19

14 Nov '19

Dear all, I am writing to invite you to our next meeting of the Cosmology Journal Club in which we will discuss the paper "Planck evidence for a closed Universe and a possible crisis for cosmology" from Eleonora Di Valentino, Alessandro Melchiorri and Joseph Silk, published recently on Nature Astronomy, https://www.nature.com/articles/s41550-019-0906-9, and also available on ArXiv at the link below, https://arxiv.org/abs/1911.02087. The paper has attracted the media attention since it calls for a serious rethinking of the concordance model of cosmology. The meeting will take place at the Institute of Astronomy, in the Conference room at 12.15. Come join the discussion if you want to know more. Best Regards, Matteo Cinus

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Cosmo journal club 4.11.2019 @ 12:15 KRA, Piwnice
by Justyna Borkowska 03 Nov '19

03 Nov '19

Hi all, at tomorrow's journal club (KRA Piwnice, after the seminar) I'd like to discuss the https://arxiv.org/abs/1909.13489 article ("Another look at redshift drift and the backreaction conjecture"). See you tomorrow, Cheers Justyna

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Cosmo Jnl Club 12:15 Mon 28.X.2019 Mariana: ArXiv:1910.04750
by Mariana Jaber 25 Oct '19

25 Oct '19

Hello everybody, this is to tell you we’re discussing this paper (ArXiv:1910.04750) next journal club. The meeting will take place after Monday’s seminar, this is around 12.15hrs in Piwnice. The paper is titled “Deficit of Luminous and Normal Red Galaxies in Cosmic Voids” and I will be presenting it but please feel free to read it as well so we can discuss it together. Best, -Mariana

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LSST-PL 14 March 2019@NCBJ
by Boud Roukema 08 Mar '19

08 Mar '19

hi cosmo-torun, In case anyone is interested, a 1-day LSST-PL kick-off meeting for science and organising issues will take place on Thursday: LSST-PL 11:00-18:00 Thursday 14 March 2019@NCBJ https://events.ncbj.gov.pl/event/10/ If you are likely to attend, then please register, even if you don't intend to present a talk - this is for practical reasons in terms of handling things like the number of chairs and choice of room. pozdr Boud

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Inhomogeneous Cosmologies IV, Torun, 14-19 July 2019
by Boud Roukema 31 Jan '19

31 Jan '19

Inhomogeneous Cosmologies IV, Torun, 14-19 July 2019 During 14-19 July 2019 we are gathering experts in inhomogeneous cosmology for a small workshop of about 30 participants at Nicolaus Copernicus University in Torun, the town where Copernicus was born. We wish to map out the most promising directions for analytical, numerical and observational investigations aimed to take into account both structure formation and cosmological expansion within the constraints of general relativity. Can we clarify the physics present in the relativistic cosmology software now being developed? Are the calculations artificially constrained or are they fully relativistic? Can we achieve accurate postdiction of cosmological observations and follow up by making predictions for the upcoming decade of new major survey projects? We expect vigorous, constructive debate between "one-percenters" and "order-unity" proponents, and practical hands-on sessions of free-licensed inhomogeneous cosmology software packages. Feel free to redistribute this announcement. Check the CosmoTorun19 website or subscribe to the inhom newsletter to know when registration is open. More info: https://cosmo.torun.pl/CosmoTorun19 Newsletter 'inhom': https://cosmo.torun.pl/mailman/listinfo/inhom Contact: cosmotorun19 at cosmo.torun.pl Organising committee: Boud Roukema, Eloisa Bentivegna, Krzysztof Bolejko, Thomas Buchert, Mikolaj Korzyński, Hayley Macpherson, Jan Ostrowski, Sebastian Szybka, Eleonora Villa, David Wiltshire Topics will include: * exact cosmological solutions of the Einstein equations * averaging and backreaction in cosmology * numerical cosmological relativity * observational tests

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Hubble-Lemaitre Law
by Andrzej Marecki 31 Aug '18

31 Aug '18

30th IAU GA resolution: www.iau.org/static/archives/announcements/pdf/ann18029e.pdf -- am

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some good links on scientific writing
by Boud Roukema 04 May '15

04 May '15

hi cosmo-torun, With a search engine, anyone can easily find some good "how to write good scientific English" guides, but here are a few that seem especially useful. For our writing of journal articles, PhD theses, and lic/mag theses, I think that these could be very useful. Even if you write in Polish, many of the principles are likely to be the same. * Grammatical and scientific correctness are necessary, but not sufficient, to provide a high probability of the reader understanding some scientific text. Gopen and Swan argue that writing short sentences is not necessarily enough either; and avoiding technical language does not necessarily improve readability either. They provide concrete examples and show how and why the examples could be rewritten more clearly: http://www.americanscientist.org/issues/pub/the-science-of-scientific-writi… * The "see also" section of this Wikipedia article seems to be its most useful part: https://en.wikipedia.org/wiki/Scientific_writing#See_also https://en.wikipedia.org/w/index.php?title=Scientific_writing&oldid=6275008… * European scientific writing guidelines, including a partly Polish guideline of how to write in English: http://www.ease.org.uk/publications/author-guidelines http://www.ease.org.uk/sites/default/files/ease_guidelines-june2014-polish.… Cheers Boud

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arXiv:1410.1687 - measuring inhomogeneity in the metric
by Boud Roukema 14 Oct '14

14 Oct '14

hi cosmo-torun, Our new observational method of measuring inhomogeneity in the metric, and the initial results, are now public: http://arxiv.org/abs/1410.1687 This will make it even harder to explain the FLRW interpretation of observations to people just learning standard FLRW cosmology - what do "comoving coordinates" mean physically when one of the best known "comoving" tracers - the baryonic acoustic oscillation peak at about 105 Mpc/h - is an environmentally dependent length scale? I have been telling almost every monograph or cosmology class at TCfA since I arrived in Torun that a scale as large as 100 Mpc/h should definitely be considered as comoving. Now we know that that's an oversimplification. pozdr Boud

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Cosmography of the local Univese - nice animation.
by Tomasz Kazimierczak 15 Jun '14

15 Jun '14

Hi cosmo-torun, A nice animation of the local Universe made by Hélène Courtois, Daniel Pomarède, R. Brent Tully, Yehuda Hoffman, and Denis Courtois link: http://vimeo.com/66641648 and theirs publication: http://arxiv.org/abs/1306.0091 What is astonishing for me, it is velocity field and flow of matter reconstruction. Cheers, Tomek ================================================ Tomasz Kazimierczak Nicolaus Copernicus University, Torun Centre for Astronomy, Department of Radio Astronomy email: tomasz.kazimierczak(a)astro.uni.torun.pl

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B-modes: premature discovery announcement?
by Boud Roukema 23 May '14

23 May '14

hi cosmo-torun, A joint analysis of Planck and BICEP2 B modes including dust polarization uncertainty Michael J. Mortonson, Uroš Seljak http://arxiv.org/abs/1405.5857 "... The resulting joint BICEP2+Planck analysis favors solutions without gravity waves, and the upper limit on the tensor-to-scalar ratio is $r<0.11$, a slight improvement relative to the Planck analysis alone which gives $r<0.13$ ($95\%$ c.l.). The estimated amplitude of the dust polarization power spectrum is in rough agreement with expectations for this field based on HI column density. ..." Popular science description: https://www.sciencemag.org/content/344/6186/790.full pozdr Boud

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proof for gravitational waves?
by Tomasz Kazimierczak 18 Mar '14

18 Mar '14

Hi all, Hot news in media, according to which there is detection of gravitational waves by the BICEP2 experiment. It is something about messuring b-mode polarisation of CMB, that's all what I undersdand. Links: media: http://news.stanford.edu/news/2014/march/physics-cosmic-inflation-031714.ht… project: http://bicepkeck.org/ paper:http://bicepkeck.org/b2_respap_arxiv_v1.pdf Can we say it is a direct evidence for gravitational waves or rather it should be said indirect? Pozdr, Tomek

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Proposed PRISM space mission (fwd)
by Boud Roukema 11 Jul '13

11 Jul '13

> ---------- Forwarded message ---------- > Date: Wed, 10 Jul 2013 20:38:22 +0200 > From: Jacques Delabrouille ... > To: boud ... > Subject: Proposed PRISM space mission > > Dear Boud, > As you may have heard, we have answered the recent call for science themes for future ESA missions with a concept called PRISM (Polarised Radiation > Imaging and Spectroscopy Mission) -- The name was given before we heard of the NSA's version of PRISM... > As this mission might be of interest to you and your colleagues in Torun, I am sending you this information, which I encourage you to send to the > Polish community susceptible to be interested in this science, either on the theoretical or the experimental side, and/or involved in the project. > > The main idea of the mission is an ultra-sensitive spectro-polarimetric survey of the entire sky from about 30 GHz to about 6 THz. > > The science case is as broad as possible to serve a very large scientific community. The main themes for cosmology and fundamental physics are: > - A complete census of the Dark Matter, hot gas, dusty galaxies in our Hubble volume, and corresponding constraints on cosmology, dark energy, > cluster physics, structure formation, star formation, etc. > - The ultimate measurement of CMB polarization, to constrain primordial GW and inflationary scenarios > - The measurement of the CMB frequency spectrum, to explore energy injection at z<10^6 by processes such as reionization, decay of DM particles, > evaporation of mini black holes, etc. > > Details are in http://adsabs.harvard.edu/abs/2013arXiv1306.2259P and on our website (http://www.prism-mission.org). > > Do not hesitate to ask questions if you have any. Support (by signing-up and encouraging people to sign-up on our web site) would be very useful > (there are already a small number of Polish scientists who expressed interest, but I am sure many more still have not received this information). > > Best, > > Jacques > > > ----------------------------------------------------------------- > Jacques Delabrouille > CNRS, Laboratoire APC, > Université Paris Diderot, Bâtiment Condorcet > 10, rue Alice Domon et Léonie Duquet > 75205 Paris cedex 13, FRANCE > Telephone: +33 1 57 27 60 40 > Fax: +33 1 57 27 60 71 > ----------------------------------------------------------------- > http://www.apc.univ-paris7.fr/~delabrou/ > -----------------------------------------------------------------

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Mon 24 June 2013 cosmo workshop proposal
by Boud Roukema 23 Jun '13

23 Jun '13

hi everyone Here's my proposal for our workshop Monday 24 June. Each speaker is free to divide up the 30 minutes how he wishes, but the aim is for this to be interactive, so I suggest a maximum of 15-20 minutes of "presentation". TCfA Cosmology workshop 24.06.2013 @KRA 14:00 Roukema - TCfA cosmology group 14:20 Lew - Search for SZ galaxy clusters in simulations 14:50 - 10 minutes break 15:00 Kazimierczak - cosmic topology 15:30 Fujii - Nontoroidal topological lensing among SDSS quasars 16:00 Buliński - cosmic topology 16:10 - 10 minutes break 16:40 Ostrowski - inhomogeneous cosmo - Lagrangian approach 17:10 Matczyński - cosmology tools: IPython Może być? pozdr boud

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Planck pdf presentations
by Boud Roukema 19 Apr '13

19 Apr '13

hi cosmo-torun Some Planck pdf presentations: http://www.rssd.esa.int/index.php?project=PLANCK&page=47_ESLAB pozdr boud

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CMB data from PLANCK revealed
by Tomasz Kazimierczak 22 Mar '13

22 Mar '13

Hi cosmo-torun, First CMB data from PLANCK mission revealed! http://www.esa.int/Our_Activities/Space_Science/Planck/Planck_reveals_an_al… Pozdr, Tomek

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13:00 Fri 22 Mar: Virialization-induced curvature as a physical explanation for dark energy
by Boud Roukema 20 Mar '13

20 Mar '13

hi cosmo-torun For this Friday I propose a combined workshop and "Kosmologia" lecture. The one-line sound-bite is: "dark energy is the ordinary, relativistic, negative curvature of voids, which FLRW doesn't allow". 13:00 Fri 22 Mar: Virialization-induced curvature as a physical explanation for dark energy Abstract: "Dark energy" occurs during the redshift range over which the Universe becomes virialised, i.e. inhomogeneous, meaning that the homogeneous model should fail. Adding virialisation-induced negative curvature (of voids) to an Einstein-de Sitter (Omega_m = 1, Omega_Lambda = 0) model brings its d_L(z) relation close to that of the standard, Newtonian-void LambdaCDM model. Dark energy is most simply interpreted as an artefact of forcing voids to be flat, Newtonian voids. URL: http://arXiv.org/abs/1303.4444 For official "Kosmologia" hours, the doktoranci should stay a little longer for discussion. pozdr boud

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linear perturbation theory - special Kosmologia session 16-17.40 Thur 21 Feb
by Boud Roukema 22 Feb '13

22 Feb '13

witam cosmo-torun Tomorrow Thursday 21 Feb from 16.00 @KRA, Jan will give a talk on linear perturbation theory in cosmology. This is officially Jan's exam for the Kosmologia course, but scientifically it should be interesting for everyone in the cosmology group, especially Zbyszek and Maciej S. Galaxies exist: we need to understand how to quantitatively, statistically model their existence in a relativistic universe model - but this talk will mostly focus on the standard (Newtonian cosmology) approach. pozdr boud _______________________________________________ Cosmo-torun mailing list Cosmo-torun(a)cosmo.torun.pl http://cosmo.torun.pl/mailman/listinfo/cosmo-torun

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inhomogeneous workshop: BKS Tues 18 Dec 12:30-15:30 @KRA
by Boud Roukema 17 Dec '12

17 Dec '12

hi everyone Inhomogeneous workshop Tues 18 Dec 12:30-15:30 @KRA. This is mainly for people directly working on inhomogeneous cosmo topics, but others are welcome to come along and participate in part of the discussions - you don't have to stay for the full session! Main topic: work/talk through BKS: http://cdsads.u-strasbg.fr/abs/2000PhRvD..62d3525B see you tomorrow boud _______________________________________________ Cosmo-torun mailing list Cosmo-torun(a)cosmo.torun.pl http://cosmo.torun.pl/mailman/listinfo/cosmo-torun

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The Bohdan Paczynski Memorial Colloquium (fwd) - pierwszy wykład 16.11.2012 (fwd)
by Boud Roukema 07 Nov '12

07 Nov '12

> Szanowni Panstwo, > > Centrum Astronomiczne im. M. Kopernika PAN w Warszawie otwiera serię wykładów "The Bohdan Paczyński Memorial Colloquium". > Szczegoly na stronie: www.camk.edu.pl/PaczynskiColloquium > > Zapraszamy na pierwszy wykład, który odbędzie się 16 listopada o 15:00, > w Warszawie, ul. Bartycka 18: > > Rashid Sunyaev > > Max-Planck Institute for Astrophysics, Space Research Institute, Moscow, > Institute for Advanced Study, Princeton > > Hot Intergalactic Gas in Clusters of Galaxies,Cosmic Microwave Background Radiation and Cosmology > > Marek Abramowicz > Joanna Mikolajewska > > -------------------------------------------------------------------- > Prof. Joanna Mikolajewska Phone: +48 22 3296134 > N. Copernicus Astronomical Center Fax: +48 22 8410046 > Bartycka 18 E-mail: mikolaj camk.edu.pl > 00-716 Warszawa, Poland Web: www.camk.edu.pl > -------------------------------------------------------------------- _______________________________________________ Cosmo-torun mailing list Cosmo-torun(a)cosmo.torun.pl http://cosmo.torun.pl/mailman/listinfo/cosmo-torun

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The Bohdan Paczynski Memorial Colloquium (fwd) - pierwszy wykład 16.11.2012
by Paweł Grochowalski 06 Nov '12

06 Nov '12

Szanowni Panstwo, Centrum Astronomiczne im. M. Kopernika PAN w Warszawie otwiera serię wykładów "The Bohdan Paczyński Memorial Colloquium". Szczegoly na stronie: www.camk.edu.pl/PaczynskiColloquium Zapraszamy na pierwszy wykład, który odbędzie się 16 listopada o 15:00, w Warszawie, ul. Bartycka 18: *Rashid Sunyaev* Max-Planck Institute for Astrophysics, Space Research Institute, Moscow, Institute for Advanced Study, Princeton *Hot Intergalactic Gas in Clusters of Galaxies,Cosmic Microwave Background Radiation and Cosmology* Marek Abramowicz Joanna Mikolajewska -------------------------------------------------------------------- Prof. Joanna Mikolajewska Phone: +48 22 3296134 N. Copernicus Astronomical Center Fax: +48 22 8410046 Bartycka 18 E-mail: mikolaj(a)camk.edu.pl 00-716 Warszawa, Poland Web: www.camk.edu.pl -------------------------------------------------------------------- _______________________________________________ Cosmo-torun mailing list Cosmo-torun(a)cosmo.torun.pl http://cosmo.torun.pl/mailman/listinfo/cosmo-torun

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Newtonian N-body wrong in EdS relativistic 2nd order perturbation theory above 10 Mpc
by Boud Roukema 04 Nov '12

04 Nov '12

hi everyone http://arxiv.org/abs/1207.2035 Newtonian versus relativistic cosmology Authors: Samuel F. Flender, Dominik J. Schwarz Abstract: We show how the relativistic matter and velocity power spectra behave in different gauges. We construct a new gauge where both spectra coincide with Newtonian theory on all scales. However, in this gauge there are geometric quantities present which do not exist in Newtonian theory, for example the local variation of the Hubble parameter. Comparing this quantity to second order Newtonian quantities, we find that Newtonian theory is wrong on scales larger than 10 Mpc. This undermines the reliability of Newtonian cosmological N-body simulations on these scales. What's surprising is that this is still only *perturbation* theory, it's not fully relativistic, if I understand the paper correctly. Fully relativistic calculations still remain to be done. pozdr boud _______________________________________________ Cosmo-torun mailing list Cosmo-torun(a)cosmo.torun.pl http://cosmo.torun.pl/mailman/listinfo/cosmo-torun

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A spiral galaxy at z=2.18
by Andrzej Marecki 20 Jul '12

20 Jul '12

Can a grand-design *spiral* galaxy be located at a redshift z=2.18? Yes it can! http://www.nature.com/nature/journal/v487/n7407/full/nature11256.html -- am _______________________________________________ Cosmo-torun mailing list Cosmo-torun(a)cosmo.torun.pl http://cosmo.torun.pl/mailman/listinfo/cosmo-torun

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cosmo-discussion 14:30 Fri 13 May @KRA - Narlikar visit
by Boud Roukema 19 Apr '12

19 Apr '12

hi cosmo-torun, For people who are at KRA tomorrow afternoon, i propose a brief discussion - 14:30 Fri 13 May @KRA - about suggestions/preferences for a seminar and/or workshop during Jayant Narlikar's visit to Toruń during late May. pozdr boud PS: Coming up for Fri 20 May: Karolina on reionisation.

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