Erratum: Spectral index of the Galactic foreground emission in the 50–87 MHz range
M. Spinelli,Gianni Bernardi,Gianni Bernardi,H. Garsden,Lincoln J. Greenhill,Anastasia Fialkov,Jayce Dowell,Danny C. Price,Danny C. Price +8 more
TLDR
In this paper, a subset of data from the Large-aperture Experiment to Detect the Dark Age (LEDA) in the range $50-87$~MHz and constrain the foreground spectral index in the northern sky visible from mid-latitudes.Abstract:
Total-power radiometry with individual meter-wave antennas is a potentially effective way to study the Cosmic Dawn ($z\sim20$) through measurement of sky brightness arising from the $21$~cm transition of neutral hydrogen, provided this can be disentangled from much stronger Galactic and extra-galactic foregrounds. In the process, measured spectra of integrated sky brightness temperature can be used to quantify the foreground emission properties. In this work, we analyze a subset of data from the Large-aperture Experiment to Detect the Dark Age (LEDA) in the range $50-87$~MHz and constrain the foreground spectral index $\beta$ in the northern sky visible from mid-latitudes. We focus on two zenith-directed LEDA radiometers and study how estimates of $\beta$ vary with local sidereal time (LST). We correct for the effect of gain pattern chromaticity and compare estimated absolute temperatures with simulations. We develop a reference dataset consisting of 14 days of optimal condition observations. Using this dataset we estimate, for one radiometer, that $\beta$ varies from $-2.55$ at LST~$<6$~h to a steeper $-2.58$ at LST~$\sim13$~h, consistently with sky models and previous southern sky measurements. In the LST~$=13-24$~h range, however, we find that $\beta$ fluctuates between $-2.55$ and $-2.61$ (data scatter $\sim0.01$). We observe a similar $\beta$ vs. LST trend for the second radiometer, although with slightly smaller $|\beta|$, in the $-2.46<\beta<-2.43$ range, over $24$~h of LST (data scatter $\sim0.02$). Combining all data gathered during the extended campaign between mid-2018 to mid-2019, and focusing on the LST~$=9-12.5$~h range, we infer good instrument stability and find $-2.56<\beta<-2.50$ with $0.09<\Delta\beta<0.12$.read more
Citations
More filters
Journal ArticleDOI
The REACH radiometer for detecting the 21-cm hydrogen signal from redshift z ≈ 7.5–28
Eloy de Lera Acedo,Dirk I. L. de Villiers,Nima Razavi-Ghods,Will Handley,Anastasia Fialkov,Alessio Magro,D. A. Anstey,H.T.J. Bevins,Riccardo Chiello,J. Cumner,Alec Josaitis,I. L. V. Roque,Peter Sims,Kilian H. Scheutwinkel,Paul Alexander,Gianni Bernardi,Steven Carey,Jean Cavillot,W. Croukamp,John Ely,Thomas Gessey-Jones,Quentin Gueuning,R. Hills,Gauri V. Kulkarni,Roberto Maiolino,P. Daniel Meerburg,Shikhar Mittal,Jonathan K. Pritchard,Ewald Puchwein,A. Saxena,E Shen,Oleg Smirnov,M. Spinelli,Kristian Zarb-Adami +33 more
TL;DR: The Radio Experiment for the Analysis of Cosmic Hydrogen (REACH) is a sky-averaged 21 cm experiment aiming at improving the current observations by tackling the issues faced by current instruments related to residual systematic signals in the data as mentioned in this paper .
Journal ArticleDOI
A 21-cm power spectrum at 48 MHz, using the owens valley long wavelength array
H. Garsden,H. Garsden,Lincoln J. Greenhill,Gianni Bernardi,Gianni Bernardi,Anastasia Fialkov,Danny C. Price,Danny C. Price,Daniel A. Mitchell,Jayce Dowell,M. Spinelli,Frank K. Schinzel +11 more
TL;DR: In this paper, a 2D cylindrical spatial power spectrum for data at 43.1-53.5 MHz incoherently integrated for 4 hours was presented, and an analysis of the array sensitivity was performed.
Journal ArticleDOI
BURSTT: Bustling Universe Radio Survey Telescope in Taiwan
Hsiu-Hsien Lin,Kai-Yang Lin,Chaofang Li,Yao-Huan Tseng,Homin Jiang,Jen-Hung Wang,Jen-Chieh Cheng,Ue Li Pen,Ming-Tang Chen,Pisin Chen,Yaocheng Chen,Tomotsugu Goto,Tetsuya Hashimoto,Yuh-Jing Hwang,S. K. King,Derek Kubo,Chung-Yun Kuo,Adam Mills,J. W. Nam,Peter Oshiro,Chang-Shao Shen,Hsien Chun Tseng,Shi‐hao Wang,Vigo Feng-Shun Wu,Geoffrey C. Bower,Shu Hao Chang,Pai-An Chen,Ying Chen,Yi-Kuan Chiang,Anatoli Fedynitch,N. V. Gusinskaia,Simon C. C. Ho,Tiger Yu-Yang Hsiao,Chin-Ping Hu,Yau De Huang,J. M. Jáuregui-García,Seong-Jin Kim,C. Y. Kuo,Decmend Fang-Jie Ling,Alvina Y. L. On,Jeffrey B. Peterson,Bjorn Jasper R. Raquel,Shih-Chieh Su,Yuri Uno,Cossas K. W. Wu,Shotaro Yamasaki,Hongguo Zhu +46 more
TL;DR: The Bustling Universe Radio Survey Telescope in Taiwan (BURSTT) is optimized to discover and localize a large sample of rare, high-fluence, and nearby fast radio bursts as mentioned in this paper .
Journal ArticleDOI
Heating and Ionization of the Intergalactic Medium by an Early X-Ray Background
TL;DR: In this article, the impact of an X-ray background, such as high-energy photons from early quasars, on the temperature and ionization of the intergalactic medium prior to reionization, before the fully ionized bubbles associated with individual sources have overlapped.
Peer Review
Snowmass2021 Cosmic Frontier White Paper: 21cm Radiation as a Probe of Physics Across Cosmic Ages
TL;DR: The 21 cm line refers to a forbidden transition in neutral hydrogen associated with alignment of spins of the proton and electron and is a very low energy transition that is emitted whenever there is neutral hydrogen in the Universe as discussed by the authors .
References
More filters
Journal ArticleDOI
HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
Krzysztof M. Gorski,E. Hivon,A. J. Banday,Benjamin D. Wandelt,F. K. Hansen,Martin Reinecke,M. Bartelman +6 more
TL;DR: The Hierarchical Equal Area iso-Latitude Pixelization (HEALPix) as discussed by the authors is a data structure with an associated library of computational algorithms and visualization software that supports fast scientific applications executable directly on very large volumes of astronomical data and large area surveys in the form of discretized spherical maps.
Journal ArticleDOI
SparsePak: A Formatted Fiber Field Unit for the WIYN Telescope Bench Spectrograph. I. Design, Construction, and Calibration
TL;DR: In this paper, the authors describe the design and construction of a formatted fiber field unit, SparsePak, and characterize its optical and astrometric performance for spectroscopy of low surface brightness extended sources in the visible and near-infrared.
Journal ArticleDOI
Cosmology at low frequencies: The 21 cm transition and the high-redshift Universe
TL;DR: In this article, the physics of the 21 cm transition were reviewed, focusing on processes relevant at high redshifts, and the insights to be gained from such observations were described.
Journal ArticleDOI
An absorption profile centred at 78 megahertz in the sky-averaged spectrum
Judd D. Bowman,Alan E. E. Rogers,Raul A. Monsalve,Raul A. Monsalve,Raul A. Monsalve,Thomas J. Mozdzen,Nivedita Mahesh +6 more
TL;DR: The detection of a flattened absorption profile in the sky-averaged radio spectrum that is largely consistent with expectations for the 21-centimetre signal induced by early stars; however, the best-fitting amplitude of the profile is more than a factor of two greater than the largest predictions.
Journal ArticleDOI
Excitation of the Hydrogen 21-CM Line
TL;DR: In this paper, the importance of spin temperature for 21 cm line studies is reviewed, and four mechanisms which affect it are studied, two of which are collisions with free electrons and interactions with light.
Related Papers (5)
The C-Band All-Sky Survey (C-BASS): design and capabilities
M. Jones,Angela C. Taylor,Moumita Aich,Charles Copley,Charles Copley,H. Cynthia Chiang,R. J. Davis,Clive Dickinson,R. D. P. Grumitt,Yaser Hafez,H M Heilgendorff,C. M. Holler,C. M. Holler,M. O. Irfan,M. O. Irfan,Luke R. P. Jew,J. J. John,Justin L. Jonas,O. G. King,O. G. King,J. P. Leahy,Jamie Leech,E. M. Leitch,Stephen Muchovej,T. J. Pearson,Michael W. Peel,Michael W. Peel,A. C. S. Readhead,Jonathan Sievers,Mark Stevenson,Joe Zuntz,Joe Zuntz,Joe Zuntz +32 more
A Perturbative Analysis of Synchrotron Spectral Index Variation over the Microwave Sky
Rajib Saha,Pavan K. Aluri +1 more