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By obtaining photometric redshift information, tomography allows us to cross-correlate galaxy ellipticities in different source redshift bins. The cross-correlation is non-vanishing because the different bins share much of the foreground…

Astrophysics · Physics 2009-11-10 Masahiro Takada , Martin White

When analyzing galaxy clustering in multi-band imaging surveys, there is a trade-off between selecting the largest galaxy samples (to minimize the shot noise) and selecting samples with the best photometric redshift (photo-z) precision,…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-07 Dimitrios Tanoglidis , Chihway Chang , Joshua Frieman

We highlight the flexibility of the IPSO experiment-design framework by contrasting its application to CMB, weak lensing and redshift surveys. We illustrate the latter with a 10 parameter MCMC D-optimisation of a dark energy redshift…

Astrophysics · Physics 2009-11-10 Bruce A. Bassett , David Parkinson , Robert C. Nichol

Cosmic shear constrains cosmology by exploiting the apparent alignments of pairs of galaxies due to gravitational lensing by intervening mass clumps. However galaxies may become (intrinsically) aligned with each other, and with nearby mass…

Astrophysics · Physics 2009-06-23 Sarah Bridle , Lindsay King

We use the mock catalog of galaxies, constructed based on the COSMOS galaxy catalog including information on photometric redshifts (photo-z) and SED types of galaxies, in order to study how to define a galaxy subsample suitable for weak…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Atsushi J. Nishizawa , Masahiro Takada , Takashi Hamana , Hisanori Furusawa

Photometric redshift estimation is an indispensable tool of precision cosmology. One problem that plagues the use of this tool in the era of large-scale sky surveys is that the bright galaxies that are selected for spectroscopic observation…

Instrumentation and Methods for Astrophysics · Physics 2017-07-18 Peter E. Freeman , Rafael Izbicki , Ann B. Lee

Cosmic shear has been identified as the method with the most potential to constrain dark energy. To capitalise on this potential it is necessary to measure galaxy shapes with great accuracy, which in turn requires a detailed model for the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 L. M. Voigt , S. L. Bridle , A. Amara , M. Cropper , T. D. Kitching , R. Massey , J. Rhodes , T. Schrabback

The abundance of peaks in weak gravitational lensing maps is a potentially powerful cosmological tool, complementary to measurements of the shear power spectrum. We study peaks detected directly in shear maps, rather than convergence maps,…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-16 Nicolas Martinet , James G. Bartlett , Alina Kiessling , Barbara Sartoris

Broadband time-ordered data obtained from telescopes with a wavelength-dependent, asymmetric beam pattern can be used to extract maps at multiple wavelengths from a single scan. This technique is especially useful when collecting data on…

Instrumentation and Methods for Astrophysics · Physics 2023-06-06 Brianna Cantrall , Solomon Quinn , Emory F. Bunn

Cosmic shear is a powerful method to constrain cosmology, provided that any systematic effects are under control. The intrinsic alignment of galaxies is expected to severely bias parameter estimates if not taken into account. We explore the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 B. Joachimi , S. L. Bridle

Since the volume accessible to galaxy surveys is fundamentally limited, it is extremely important to analyse available data in the most optimal fashion. One way of enhancing the cosmological information extracted from the clustering of…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-20 David W. Pearson , Lado Samushia , Praful Gagrani

An explicit full nulling scheme for cosmic shear observations is presented. It makes possible the construction of shear maps from extended source distributions for which the lens distance distribution is restricted to a definite interval.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Francis Bernardeau , Takahiro Nishimichi , Atsushi Taruya

Cosmic shear is one of the primary probes to test gravity with current and future surveys. There are two main techniques to analyse a cosmic shear survey; a tomographic method, where correlations between the lensing signal in different…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-14 A. Spurio Mancini , R. Reischke , V. Pettorino , B. M. Schäfer , M. Zumalacárregui

We present measurements of the weak gravitational lensing shear power spectrum based on $450$ sq. deg. of imaging data from the Kilo Degree Survey. We employ a quadratic estimator in two and three redshift bins and extract band powers of…

3D data compression techniques can be used to determine the natural basis of radial eigenmodes that encode the maximum amount of information in a tomographic large-scale structure survey. We explore the potential of the Karhunen-Lo\`eve…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-16 Emilio Bellini , David Alonso , Shahab Joudaki , Ludovic van Waerbeke

Upcoming surveys of the large-scale structure of our Universe will employ a large coverage area of about half of the sky and will significantly increase the observational depth. With these surveys, we will be able to cross-correlate CMB…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-10 Chandra Shekhar Saraf , Pawel Bielewicz

Several papers have recently highlighted the possibility of measuring redshift space distortions from angular auto-correlations of galaxies in photometric redshift bins. In this work we extend this idea to include as observables the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-10 Jacobo Asorey , Martin Crocce , Enrique Gaztanaga

Standard cosmological weak lensing analyses using cosmic shear are inevitably sensitive to small-scale, non-linear clustering from low-redshift structures. The need to adequately model the clustering of matter on this non-linear regime,…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-25 Giulia Piccirilli , Matteo Zennaro , Carlos García-García , David Alonso

A theoretical framework is developed to estimate the optimal binning of X-ray spectra. We derived expressions for the optimal bin size for model spectra as well as for observed data using different levels of sophistication. It is shown that…

Instrumentation and Methods for Astrophysics · Physics 2016-03-09 J. S. Kaastra , J. A. M. Bleeker

In this paper, we motivate the use of galaxy clustering measurements using photometric redshift information, including a contribution from flux magnification, as a probe of cosmology. We present cosmological forecasts when clustering data…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Christopher Duncan , Benjamin Joachimi , Alan Heavens , Catherine Heymans , Hendrik Hildebrandt