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The HI 21cm absorption line is masked by bright foregrounds and systematic distortions that arise due to the chromaticity of the antenna used to make the observation coupling to the spectral inhomogeneity of these foregrounds. We…

天体物理仪器与方法 · 物理学 2021-11-12 Dominic Anstey , Eloy de Lera Acedo , Will Handley

Observations of the EoR with the 21-cm hyperfine emission of neutral hydrogen (HI) promise to open an entirely new window onto the formation of the first stars, galaxies and accreting black holes. In order to characterize the weak 21-cm…

宇宙学与河外天体物理 · 物理学 2015-08-06 Abhik Ghosh , L. V. E. Koopmans , Emma Chapman , Vibor Jelic

The concordance of the $\Lambda$CDM cosmological model in light of current observations has been the subject of an intense debate in recent months. The 2018 Planck Cosmic Microwave Background (CMB) temperature anisotropy power spectrum…

宇宙学与河外天体物理 · 物理学 2021-07-02 Sunny Vagnozzi , Eleonora Di Valentino , Stefano Gariazzo , Alessandro Melchiorri , Olga Mena , Joseph Silk

In the next decades, it is necessary to forge new late-universe cosmological probes to precisely constrain the Hubble constant and the equation of state of dark energy simultaneously. In this work, we show that the four typical…

宇宙学与河外天体物理 · 物理学 2023-06-26 Peng-Ju Wu , Yue Shao , Shang-Jie Jin , Xin Zhang

L-BASS is an instrument designed to produce an absolutely calibrated map of the sky at a wavelength of 21 cm (L-band) with a radiometric accuracy of less than or equal to 0.1 K and with an angular resolution of 23 degrees. The prime…

天体物理仪器与方法 · 物理学 2025-06-06 D. P. Zerafa , P. N. Wilkinson , C. J. Radcliffe , J. P. Leahy , I. W. A. Browne , P. J. Black

We use hierarchical Bayesian modelling to calibrate a network of 32 all-sky faint DA white dwarf (DA WD) spectrophotometric standards ($16.5 < V < 19.5$) alongside three CALSPEC standards, from 912 \r{A} to 32 $\mu$m. The framework is the…

Gamma-ray burst (GRB) prompt emission is highly beamed, and understanding the jet geometry and beaming configuration can provide information on the poorly understood central engine and circum-burst environment. Prior to the advent of…

高能天体物理现象 · 物理学 2020-04-21 Sylvia Biscoveanu , Eric Thrane , Salvatore Vitale

The Parkes Galactic All-Sky Survey (GASS) is a survey of Galactic atomic hydrogen (HI) emission in the southern sky observed with the Parkes 64-m Radio Telescope. The first data release was published by McClure-Griffiths et al. (2009). We…

Measurement of the angular power spectrum of the cosmic microwave background is most often based on a spherical harmonic analysis of the observed temperature anisotropies. Even if all-sky maps are obtained, however, it is likely that the…

天体物理学 · 物理学 2009-10-31 Daniel J. Mortlock , Anthony D. Challinor , Michael P. Hobson

We present the final data release of observations of lambda 21-cm emission from Galactic neutral hydrogen over the entire sky, merging the Leiden/Dwingeloo Survey (LDS: Hartmann & Burton, 1997) of the sky north of delta = -30 deg with the…

天体物理学 · 物理学 2010-11-09 P. M. W. Kalberla , W. B. Burton , Dap Hartmann , E. M. Arnal , E. Bajaja , R. Morras , W. G. L. Poppel

The natural approach to a spectral analysis of data distributed on the sky employs spherical harmonic decomposition. A common problem encountered in practical astronomy is the lack of full sky coverage in the available data. For example,…

天体物理学 · 物理学 2009-10-22 Krzysztof M. Gorski

Recently, the Large High-Altitude Air Shower Observatory (LHAASO) collaboration has obtained a measurement of the gamma-ray diffuse emission in the ultra-high energy range, $10-10^3$ TeV after masking the contribution of known sources. The…

In the 1998-99 flight, BOOMERanG has produced maps of $\sim 4 %$ of the sky at high Galactic latitudes, at frequencies of 90, 150, 240 and 410 GHz, with resolution $\simgt 10'$. The faint structure of the Cosmic Microwave Background at…

The GMRT reionization effort aims to map out the large scale structure of the Universe during the epoch of reionization (EoR). Removal of polarized Galactic emission is a difficult part of any 21 cm EoR program, and we present new upper…

Aiming to fill a crucial gap in our observational knowledge of the early Universe, experiments around the world continue to attempt to verify the claimed detection of the redshifted 21-cm signal from Cosmic Dawn by the EDGES experiment.…

宇宙学与河外天体物理 · 物理学 2020-09-15 B. McKinley , C. M. Trott , M. Sokolowski , R. B. Wayth , A. Sutinjo , N. Patra , J. Nambissan T. , D. C. X. Ung

The decomposition of the cosmic shear field into E- and B-mode is an important diagnostic in weak gravitational lensing. However, commonly used techniques to perform this separation suffer from mode-mixing on very small or very large…

宇宙学与河外天体物理 · 物理学 2015-05-13 Liping Fu , Martin Kilbinger

We present the application of the pseudo-spectrum method to galaxy-galaxy lensing. We derive explicit expressions for the pseudo-spectrum analysis of the galaxy-shear cross spectrum, which is the Fourier space counterpart of the stacked…

宇宙学与河外天体物理 · 物理学 2017-07-25 Chiaki Hikage , Masamune Oguri

We present an improved zodiacal light model, optimized for optical wavelengths, using archival Hubble Space Telescope (HST) imaging from the SKYSURF program. The Kelsall et al. 1998 model used infrared imaging from the Diffuse Infrared…

Fitting parameterized models to images of galaxies has become the standard for measuring galaxy morphology. This forward modelling technique allows one to account for the PSF to effectively study semi-resolved galaxies. However, using a…

星系天体物理 · 物理学 2021-12-22 Tim B. Miller , Pieter van Dokkum

A scheme for estimating atmospheric parameters T$_{eff}$, log$~g$, and [Fe/H] is proposed on the basis of Least Absolute Shrinkage and Selection Operator (LASSO) algorithm and Haar wavelet. The proposed scheme consists of three processes. A…

太阳与恒星天体物理 · 物理学 2015-08-04 Yu Lu , Xiangru Li