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healpy: equal area pixelization and spherical harmonics transforms for data on the sphere in Python

Andrea Zonca, Leo Singer, Daniel Lenz, Martin Reinecke, Cyrille Rosset, Eric Hivon, Krzysztof Gorski
2019 Journal of Open Source Software  
Acknowledgements We acknowledge the Planck collaboration and in particular Peter Meinhold, Julian Borrill and Charles Lawrence for supporting Andrea Zonca's work on the project.  ...  We thank all past and current contributors. For a full overview, see the latest list of contributors on Github.  ...  Zonca et al., (2019). healpy: equal area pixelization and spherical harmonics transforms for data on the sphere in Python.  ... 
doi:10.21105/joss.01298 fatcat:phgspr65tjh6fi4hq6kupzb5fq

Multi-Resolution HEALPix Maps for Multi-Wavelength and Multi-Messenger Astronomy [article]

I. Martinez-Castellanos, Leo P. Singer, E. Burns, D. Tak, Alyson Joens, Judith L. Racusin, Jeremy S. Perkins
2021 arXiv   pre-print
HEALPix -- the Hierarchical Equal Area isoLatitude Pixelization -- has become a standard in high-energy and gravitational wave astronomy.  ...  When used for this purpose the need for a homogeneous all-sky grid represents a limitation that hinders a broader community adoption.  ...  Some of the results in this paper have been derived using the healpy and HEALPix package.  ... 
arXiv:2111.11240v1 fatcat:xyvhvlhjmvgk7m2uwhfhq77wya

Multiresolution HEALPix Maps for Multiwavelength and Multimessenger Astronomy

I. Martinez-Castellanos, Leo P. Singer, E. Burns, Donggeun Tak, Alyson Joens, Judith L. Racusin, Jeremy S. Perkins
2022 The astronomical journal 163(6)  
HEALPix—the Hierarchical Equal Area isoLatitude Pixelization—has become a standard in high-energy and gravitational wave astronomy.  ...  When used for this purpose the need for a homogeneous all-sky grid represents a limitation that hinders a broader community adoption.  ...  Single-resolution HEALPix Maps In the HEALPix standard the pixelization of the sphere begins by dividing the sphere into 12 base pixels of equal area, as shown in Figures 1(a ) and 2(a).  ... 
doi:10.3204/pubdb-2022-02571 fatcat:hdtf75aperau7exzvbvwrqjj4i

Very fast stochastic gravitational wave background map making using folded data

Anirban Ain, Jishnu Suresh, Sanjit Mitra
2018 Physical Review D  
We also incorporated well-known HEALPix pixelization tools for further standardization and optimization.  ...  Taking advantage of the compactness of the folded data we replaced the loops in the pipeline with matrix multiplications.  ...  Apart from the advantages of equal area pixels, HEALPix offers highly efficient tools for Fourier transforms on the sky, making it easy to transform a map from pixel to spherical harmonic bases and vice-versa  ... 
doi:10.1103/physrevd.98.024001 fatcat:lh46btfmxjhbbi7n3u3647j7qq

HEALPix Alchemy: Fast All-Sky Geometry and Image Arithmetic in a Relational Database for Multimessenger Astronomy Brokers [article]

Leo P. Singer, B. Parazin, Michael W. Coughlin, Joshua S. Bloom, Arien Crellin-Quick, Daniel A. Goldstein, Stéfan van der Walt
2022 arXiv   pre-print
Efficient searches for electromagnetic counterparts to gravitational wave, high-energy neutrino, and gamma-ray burst events demand rapid processing of image arithmetic and geometry set operations in a  ...  can be performed in less than a few seconds on commodity hardware using off-the-shelf cloud-managed database implementations without server-side database extensions.  ...  The open-source HEALPix Alchemy package is publicly available on GitHub (https://github.com/skyportal/ healpix-alchemy) and Zenodo (Singer et al. 2021) (Bayer 2012) , HEALPix (Górski et al. 2005 )  ... 
arXiv:2112.06947v2 fatcat:fewfbuoexfertldmdg3khsva2u

NIFTY – Numerical Information Field Theory

M. Selig, M. R. Bell, H. Junklewitz, N. Oppermann, M. Reinecke, M. Greiner, C. Pachajoa, T. A. Enßlin
2013 Astronomy and Astrophysics  
Its object-oriented framework is written in Python, although it accesses libraries written in Cython, C++, and C for efficiency.  ...  The set of spaces on which NIFTY operates comprises point sets, n-dimensional regular grids, spherical spaces, their harmonic counterparts, and product spaces constructed as combinations of those.  ...  Some of the results in this paper have been derived using the HEALPix package (Górski et al. 2005) . This research has made use of NASA's Astrophysics Data System.  ... 
doi:10.1051/0004-6361/201321236 fatcat:kggk63trkvhs5ouivztam6clte

OUP accepted manuscript

2020 Monthly notices of the Royal Astronomical Society  
The mapping technique is assessed and verified with tests on simulations; together with the Kaiser-Squires method, the technique is then applied to data from the DES Year 1 data and the differences between  ...  The technique is found to improve the map reconstruction on the edges of the field compared to the conventional Kaiser-Squires method, which applies a direct inversion on the data; our approach is in good  ...  Numerical computations were carried out on the Sciama High Performance Compute (HPC) cluster which is supported by the ICG, SEPNet and the University of Portsmouth.  ... 
doi:10.1093/mnras/staa565 fatcat:pttkilxaynhbfidf6pymxutq7m

Spherical harmonics analysis ofFermigamma-ray data and the Galactic dark matter halo

Dmitry Malyshev, Jo Bovy, Ilias Cholis
2011 Physical Review D  
Using the spherical harmonic decomposition in a window excluding the Galactic plane, we show for one year of Fermi data that adding a spherical template (such as a line-of-sight DM annihilation profile  ...  We argue that the decomposition of gamma-ray maps in spherical harmonics is a sensitive tool to study dark matter (DM) annihilation or decay in the main Galactic halo of the Milky Way.  ...  The authors are thankful to Douglas Finkbeiner, Jennifer Siegal-Gaskins, Neal Weiner, and especially to David Hogg for valuable discussions and comments. This work .  ... 
doi:10.1103/physrevd.84.023013 fatcat:z47imyvcmbhn7o3zpppxemd5ui

OUP accepted manuscript

2019 Monthly notices of the Royal Astronomical Society  
We present an augmented version of our dual messenger algorithm for spin field reconstruction on the sphere, while accounting for highly non-trivial and realistic noise models such as modulated correlated  ...  Our algorithm, therefore, has a potentially key role in the data analysis of high-resolution and high-sensitivity CMB data, especially with the range of upcoming CMB experiments tailored for the detection  ...  ACKNOWLEDGEMENTS We thank Franz Elsner for stimulating discussions on CMB data analysis pipelines.  ... 
doi:10.1093/mnras/stz2608 fatcat:7clcrljhkzb5nfvlerp2l27jsm

Characterising solar surface convection using Doppler measurements [article]

Samarth G Kashyap, Shravan M Hanasoge
2021 arXiv   pre-print
The Hierarchical Equal Area Pixelization scheme (HEALPix) is used to perform spherical harmonic transforms on the cleaned image.  ...  Poloidal flow power peaks in the range of ℓ - |m| ≈ 150-250 which may potentially hint at a latitudinal preference for convective flows.  ...  DATA ANALYSIS We perform a spectral analysis on the preprocessed data using the Python package healpy (Zonca et al. 2019 ). This is based on the HEALPix scheme.  ... 
arXiv:2105.12055v1 fatcat:ssib6s3ajffpbm3p4vloj46wpa

The Atacama Cosmology Telescope: Summary of DR4 and DR5 Data Products and Data Access [article]

Maya Mallaby-Kay, Zachary Atkins, Simone Aiola, Stefania Amodeo, Jason E. Austermann, James A. Beall, Daniel T. Becker, J. Richard Bond, Erminia Calabrese, Grace E. Chesmore, Steve K. Choi, Kevin T. Crowley (+48 others)
2021 arXiv   pre-print
The data products (excluding simulations) and the set of notebooks are publicly available on the NASA Legacy Archive for Microwave Background Data Analysis (LAMBDA); simulation products are available on  ...  Two recent large data releases for the Atacama Cosmology Telescope (ACT), called DR4 and DR5, are available for public access.  ...  These packages include HEALPix (Gorski et al. 2005 ) and the python wrapper for HEALPix which is healpy (Zonca et al. 2019) .  ... 
arXiv:2103.03154v2 fatcat:6f6bmosxergohjlpssf42nclju

Imaging the Southern Sky at 159MHz using Spherical Harmonics with the Engineering Development Array 2 [article]

Michael A. Kriele, Randall B. Wayth, Mark J. Bentum, Budi Juswardy, Cathryn M. Trott
2022 arXiv   pre-print
We also introduce a new method for visualising and quantifying how the baseline distribution of an interferometer maps to the spherical harmonics, and discuss how prior information can be used to constrain  ...  In order to achieve this, sky maps spanning a wide range of frequencies and angular scales are required for calibration and foreground subtraction.  ...  ACKNOWLEDGEMENTS We thank Daniel Ung for aiding in generating and providing the FEKO-generated EDA2 beam models.  ... 
arXiv:2201.04281v1 fatcat:g2pswontgfgvtatqw4lej27c7m

Optimal method for reconstructing polychromatic maps from broadband observations with an aysmmetric antenna pattern [article]

Brianna Cantrall, Solomon Quinn, Emory F. Bunn
2022 arXiv   pre-print
When the telescope is able to scan the sky isotropically, it is useful to transform to a spherical harmonic basis, in which this matrix has a particularly simple form.  ...  This technique is especially useful when collecting data on cosmic phenomena such as the Cosmic Microwave Background (CMB) radiation, as it provides the ability to separate the CMB signal from foreground  ...  ACKNOWLEDGMENTS Early stages of this work were supported by NSF Award 141013 and by a visitor grant from the Institut Lagrange (Paris).  ... 
arXiv:2205.07988v1 fatcat:rhmdy5euhvbfbe2ubjmwykbzv4

OUP accepted manuscript

2019 Monthly notices of the Royal Astronomical Society  
The code can be used to assess the impact of optical systematics on all stages of data reduction for a realistic experiment, including analyses beyond power spectrum estimation, by generating signal timelines  ...  The design and mathematical framework of the Python code is discussed along with a few simple benchmarking results.  ...  AJD and JEG acknowledge support by Vetenskapsrådet (Swedish Research Council) through contract No. 638-2013-8993 and the Oskar Klein Centre for Cosmoparticle Physics.  ... 
doi:10.1093/mnras/stz1143 fatcat:idtbknvvmzfjvnn3grckkk6gre

Imaging the southern sky at 159 MHz using spherical harmonics with the engineering development array 2

Michael A. Kriele, Randall B. Wayth, Mark J. Bentum, Budi Juswardy, Cathryn M. Trott
2022 Publications Astronomical Society of Australia  
We also introduce a new method for visualising and quantifying how the baseline distribution of an interferometer maps to the spherical harmonics and discuss how prior information can be used to constrain  ...  In order to achieve this, sky maps spanning a wide range of frequencies and angular scales are required for calibration and foreground subtraction.  ...  We thank Daniel Ung for aiding in generating and providing the FEKO-generated EDA2 beam models.  ... 
doi:10.1017/pasa.2022.2 fatcat:asy4zdb5drbsjpqvbs3ann5ase
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