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  1. Book ; Online: Analysing the Epoch of Reionization with three-point correlation functions and machine learning techniques

    Jennings, W. D. / Watkinson, C. A. / Abdalla, F. B.

    2020  

    Abstract: Three-point and high-order clustering statistics of the high-redshift 21cm signal contain valuable information about the Epoch of Reionization. We present 3PCF-Fast, an optimised code for estimating the three-point correlation function of 3D pixelised ... ...

    Abstract Three-point and high-order clustering statistics of the high-redshift 21cm signal contain valuable information about the Epoch of Reionization. We present 3PCF-Fast, an optimised code for estimating the three-point correlation function of 3D pixelised data such as the outputs from numerical and semi-numerical simulations. After testing 3PCF-Fast on data with known analytic three-point correlation function, we use machine learning techniques to recover the mean bubble size and global ionisation fraction from correlations in the outputs of the publicly available 21cmFAST code. We assume that foregrounds have been perfectly removed and negligible instrumental noise. Using ionisation fraction data, our best MLP model recovers the mean bubble size with a median prediction error of around 10%, or from the 21cm differential brightness temperature with median prediction error of around 14%. A further two MLP models recover the global ionisation fraction with median prediction errors of around 4% (using ionisation fraction data) or around 16% (using brightness temperature). Our results indicate that clustering in both the ionisation fraction field and the brightness temperature field encode useful information about the progress of the Epoch of Reionization in a complementary way to other summary statistics. Using clustering would be particularly useful in regimes where high signal-to-noise ratio prevents direct measurement of bubble size statistics. We compare the quality of MLP models using the power spectrum, and find that using the three-point correlation function outperforms the power spectrum at predicting both global ionisation fraction and mean bubble size.
    Keywords Astrophysics - Cosmology and Nongalactic Astrophysics
    Subject code 612
    Publishing date 2020-11-28
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Large-Scale Distribution of Total Mass versus Luminous Matter from Baryon Acoustic Oscillations: First Search in the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey Data Release 10.

    Soumagnac, M T / Barkana, R / Sabiu, C G / Loeb, A / Ross, A J / Abdalla, F B / Balan, S T / Lahav, O

    Physical review letters

    2016  Volume 116, Issue 20, Page(s) 201302

    Abstract: Baryon acoustic oscillations in the early Universe are predicted to leave an as yet undetected signature on the relative clustering of total mass versus luminous matter. A detection of this effect would provide an important confirmation of the standard ... ...

    Abstract Baryon acoustic oscillations in the early Universe are predicted to leave an as yet undetected signature on the relative clustering of total mass versus luminous matter. A detection of this effect would provide an important confirmation of the standard cosmological paradigm and constrain alternatives to dark matter as well as nonstandard fluctuations such as compensated isocurvature perturbations (CIPs). We conduct the first observational search for this effect, by comparing the number-weighted and luminosity-weighted correlation functions, using the SDSS-III BOSS Data Release 10 CMASS sample. When including CIPs in our model, we formally obtain evidence at 3.2σ of the relative clustering signature and a limit that matches the existing upper limits on the amplitude of CIPs. However, various tests suggest that these results are not yet robust, perhaps due to systematic biases in the data. The method developed in this Letter used with more accurate future data such as that from DESI, is likely to confirm or disprove our preliminary evidence.
    Language English
    Publishing date 2016-05-20
    Publishing country United States
    Document type Journal Article
    ZDB-ID 208853-8
    ISSN 1079-7114 ; 0031-9007
    ISSN (online) 1079-7114
    ISSN 0031-9007
    DOI 10.1103/PhysRevLett.116.201302
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Book ; Online: BeyondPlanck IV. On end-to-end simulations in CMB analysis -- Bayesian versus frequentist statistics

    Brilenkov, M. / Fornazier, K. S. F. / Hergt, L. T. / Hoerning, G. A. / Marins, A. / Murokoshi, T. / Rahman, F. / Stutzer, N. -O. / Zhou, Y. / Abdalla, F. B. / Andersen, K. J. / Aurlien, R. / Banerji, R. / Basyrov, A. / Battista, A. / Bersanelli, M. / Bertocco, S. / Bollanos, S. / Colombo, L. P. L. /
    Eriksen, H. K. / Eskilt, J. R. / Foss, M. K. / Franceschet, C. / Fuskeland, U. / Galeotta, S. / Galloway, M. / Gerakakis, S. / Gjerlow, E. / Hensley, B. / Herman, D. / Hoang, T. D. / Ieronymaki, M. / Ihle, H. T. / Jewell, J. B. / Karakci, A. / Keihanen, E. / Keskitalo, R. / Maggio, G. / Maino, D. / Maris, M. / Paradiso, S. / Partridge, B. / Reinecke, M. / Suur-Uski, A. -S. / Svalheim, T. L. / Tavagnacco, D. / Thommesen, H. / Tomasi, M. / Watts, D. J. / Wehus, I. K. / Zacchei, A.

    2022  

    Abstract: End-to-end simulations play a key role in the analysis of any high-sensitivity CMB experiment, providing high-fidelity systematic error propagation capabilities unmatched by any other means. In this paper, we address an important issue regarding such ... ...

    Abstract End-to-end simulations play a key role in the analysis of any high-sensitivity CMB experiment, providing high-fidelity systematic error propagation capabilities unmatched by any other means. In this paper, we address an important issue regarding such simulations, namely how to define the inputs in terms of sky model and instrument parameters. These may either be taken as a constrained realization derived from the data, or as a random realization independent from the data. We refer to these as Bayesian and frequentist simulations, respectively. We show that the two options lead to significantly different correlation structures, as frequentist simulations, contrary to Bayesian simulations, effectively include cosmic variance, but exclude realization-specific correlations from non-linear degeneracies. Consequently, they quantify fundamentally different types of uncertainties, and we argue that they therefore also have different and complementary scientific uses, even if this dichotomy is not absolute. Before BeyondPlanck, most pipelines have used a mix of constrained and random inputs, and used the same hybrid simulations for all applications, even though the statistical justification for this is not always evident. BeyondPlanck represents the first end-to-end CMB simulation framework that is able to generate both types of simulations, and these new capabilities have brought this topic to the forefront. The Bayesian BeyondPlanck simulations and their uses are described extensively in a suite of companion papers. In this paper we consider one important applications of the corresponding frequentist simulations, namely code validation. That is, we generate a set of 1-year LFI 30 GHz frequentist simulations with known inputs, and use these to validate the core low-level BeyondPlanck algorithms; gain estimation, correlated noise estimation, and mapmaking.
    Keywords Astrophysics - Cosmology and Nongalactic Astrophysics
    Subject code 612
    Publishing date 2022-09-09
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Wide-Field Lensing Mass Maps from Dark Energy Survey Science Verification Data.

    Chang, C / Vikram, V / Jain, B / Bacon, D / Amara, A / Becker, M R / Bernstein, G / Bonnett, C / Bridle, S / Brout, D / Busha, M / Frieman, J / Gaztanaga, E / Hartley, W / Jarvis, M / Kacprzak, T / Kovács, A / Lahav, O / Lin, H /
    Melchior, P / Peiris, H / Rozo, E / Rykoff, E / Sánchez, C / Sheldon, E / Troxel, M A / Wechsler, R / Zuntz, J / Abbott, T / Abdalla, F B / Allam, S / Annis, J / Bauer, A H / Benoit-Lévy, A / Brooks, D / Buckley-Geer, E / Burke, D L / Capozzi, D / Carnero Rosell, A / Carrasco Kind, M / Castander, F J / Crocce, M / D'Andrea, C B / Desai, S / Diehl, H T / Dietrich, J P / Doel, P / Eifler, T F / Evrard, A E / Fausti Neto, A / Flaugher, B / Fosalba, P / Gruen, D / Gruendl, R A / Gutierrez, G / Honscheid, K / James, D / Kent, S / Kuehn, K / Kuropatkin, N / Maia, M A G / March, M / Martini, P / Merritt, K W / Miller, C J / Miquel, R / Neilsen, E / Nichol, R C / Ogando, R / Plazas, A A / Romer, A K / Roodman, A / Sako, M / Sanchez, E / Sevilla, I / Smith, R C / Soares-Santos, M / Sobreira, F / Suchyta, E / Tarle, G / Thaler, J / Thomas, D / Tucker, D / Walker, A R

    Physical review letters

    2015  Volume 115, Issue 5, Page(s) 51301

    Abstract: We present a mass map reconstructed from weak gravitational lensing shear measurements over 139  deg2 from the Dark Energy Survey science verification data. The mass map probes both luminous and dark matter, thus providing a tool for studying cosmology. ... ...

    Abstract We present a mass map reconstructed from weak gravitational lensing shear measurements over 139  deg2 from the Dark Energy Survey science verification data. The mass map probes both luminous and dark matter, thus providing a tool for studying cosmology. We find good agreement between the mass map and the distribution of massive galaxy clusters identified using a red-sequence cluster finder. Potential candidates for superclusters and voids are identified using these maps. We measure the cross-correlation between the mass map and a magnitude-limited foreground galaxy sample and find a detection at the 6.8σ level with 20 arc min smoothing. These measurements are consistent with simulated galaxy catalogs based on N-body simulations from a cold dark matter model with a cosmological constant. This suggests low systematics uncertainties in the map. We summarize our key findings in this Letter; the detailed methodology and tests for systematics are presented in a companion paper.
    Language English
    Publishing date 2015-07-31
    Publishing country United States
    Document type Journal Article
    ZDB-ID 208853-8
    ISSN 1079-7114 ; 0031-9007
    ISSN (online) 1079-7114
    ISSN 0031-9007
    DOI 10.1103/PhysRevLett.115.051301
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Bonn / Germany

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    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  5. Book ; Online: Initial deep LOFAR observations of Epoch of Reionization windows

    Yatawatta, S. / de Bruyn, A. G. / Brentjens, M. A. / Labropoulos, P. / Pandey, V. N. / Kazemi, S. / Zaroubi, S. / Koopmans, L. V. E. / Offringa, A. R. / Jelic, V. / Rubi, O. Martinez / Veligatla, V. / Wijnholds, S. J. / Brouw, W. N. / Bernardi, G. / Ciardi, B. / Daiboo, S. / Harker, G. / Mellema, G. /
    Schaye, J. / Thomas, R. / Vedantham, H. / Chapman, E. / Abdalla, F. B. / Alexov, A. / Anderson, J. / Avruch, I. M. / Batejat, F. / Bell, M. E. / Bell, M. R. / Bentum, M. / Best, P. / Bonafede, A. / Bregman, J. / Breitling, F. / van de Brink, R. H. / Broderick, J. W. / Bruggen, M. / Conway, J. / de Gasperin, F. / de Geus, E. / Duscha, S. / Falcke, H. / Fallows, R. A. / Ferrari, C. / Frieswijk, W. / Garrett, M. A. / Griessmeier, J. M. / Gunst, A. W. / Hassall, T. E. / Hessels, J. W. T. / Hoeft, M. / Iacobelli, M. / Juette, E. / Karastergiou, A. / Kondratiev, V. I. / Kramer, M. / Kuniyoshi, M. / Kuper, G. / van Leeuwen, J. / Maat, P. / Mann, G. / McKean, J. P. / Mevius, M. / Mol, J. D. / Munk, H. / Nijboer, R. / Noordam, J. E. / Norden, M. J. / Orru, E. / Paas, H. / Pandey-Pommier, M. / Pizzo, R. / Polatidis, A. G. / Reich, W. / Rottgering, H. J. A. / Sluman, J. / Smirnov, O. / Stappers, B. / Steinmetz, M. / Tagger, M. / Tang, Y. / Tasse, C. / ter Veen, S. / Vermeulen, R. / van Weeren, R. J. / Wise, M. / Wucknitz, O. / Zarka, P.

    I. The North Celestial Pole

    2013  

    Abstract: The aim of the LOFAR Epoch of Reionization (EoR) project is to detect the spectral fluctuations of the redshifted HI 21cm signal. This signal is weaker by several orders of magnitude than the astrophysical foreground signals and hence, in order to ... ...

    Abstract The aim of the LOFAR Epoch of Reionization (EoR) project is to detect the spectral fluctuations of the redshifted HI 21cm signal. This signal is weaker by several orders of magnitude than the astrophysical foreground signals and hence, in order to achieve this, very long integrations, accurate calibration for stations and ionosphere and reliable foreground removal are essential. One of the prospective observing windows for the LOFAR EoR project will be centered at the North Celestial Pole (NCP). We present results from observations of the NCP window using the LOFAR highband antenna (HBA) array in the frequency range 115 MHz to 163 MHz. The data were obtained in April 2011 during the commissioning phase of LOFAR. We used baselines up to about 30 km. With about 3 nights, of 6 hours each, effective integration we have achieved a noise level of about 100 microJy/PSF in the NCP window. Close to the NCP, the noise level increases to about 180 microJy/PSF, mainly due to additional contamination from unsubtracted nearby sources. We estimate that in our best night, we have reached a noise level only a factor of 1.4 above the thermal limit set by the noise from our Galaxy and the receivers. Our continuum images are several times deeper than have been achieved previously using the WSRT and GMRT arrays. We derive an analytical explanation for the excess noise that we believe to be mainly due to sources at large angular separation from the NCP.

    Comment: 19 pages, 24 figures. Draft version with low resolution images. Accepted on 08/01/2013 Astronomy & Astrophysics. Abstract abridged. Version with high resolution images: http://www.astro.rug.nl/~yatawatta/ncp_eor.pdf
    Keywords Astrophysics - Instrumentation and Methods for Astrophysics ; Astrophysics - Cosmology and Nongalactic Astrophysics
    Subject code 551
    Publishing date 2013-01-08
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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