An absorption profile centred at 78 megahertz in the sky-averaged spectrum

Nature
Judd D BowmanNivedita Mahesh

Abstract

After stars formed in the early Universe, their ultraviolet light is expected, eventually, to have penetrated the primordial hydrogen gas and altered the excitation state of its 21-centimetre hyperfine line. This alteration would cause the gas to absorb photons from the cosmic microwave background, producing a spectral distortion that should be observable today at radio frequencies of less than 200 megahertz. Here we report the detection of a flattened absorption profile in the sky-averaged radio spectrum, which is centred at a frequency of 78 megahertz and has a best-fitting full-width at half-maximum of 19 megahertz and an amplitude of 0.5 kelvin. The profile 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. This discrepancy suggests that either the primordial gas was much colder than expected or the background radiation temperature was hotter than expected. Astrophysical phenomena (such as radiation from stars and stellar remnants) are unlikely to account for this discrepancy; of the proposed extensions to the standard model of cosmology and particle physics, only co...Continue Reading

References

Dec 15, 2010·Nature·Judd D Bowman, Alan E E Rogers
Jul 26, 2012·Reports on Progress in Physics·Jonathan R Pritchard, Abraham Loeb

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Citations

Mar 2, 2018·Nature·Lincoln Greenhill
Aug 8, 2018·Physical Review Letters·Maxim PospelovAlfredo Urbano
Aug 25, 2018·Physical Review Letters·Michael CrislerUNKNOWN SENSEI Collaboration
Jul 10, 2019·Physical Review Letters·Vivian PoulinMarc Kamionkowski
Mar 1, 2018·Nature·Lincoln Greenhill
Oct 9, 2018·Physical Review Letters·Julian B MuñozAbraham Loeb
Mar 9, 2019·Physical Review Letters·Gabriel MagillYu-Dai Tsai
Feb 16, 2019·Physical Review Letters·Roland de PutterJoel Meyers
Aug 16, 2019·Nature·Davide Castelvecchi
Jul 22, 2018·Physical Review Letters·Anastasia FialkovAviad Cohen
Jul 22, 2018·Physical Review Letters·Asher BerlinSamuel D McDermott
Dec 21, 2018·Nature·Judd D BowmanNivedita Mahesh
Dec 21, 2018·Nature·Richard HillsEwald Puchwein
Oct 13, 2018·Physical Review Letters·Amit BhoonahSarah Schon
Jul 22, 2018·Physical Review Letters·Guido D'AmicoAlessandro Strumia
Sep 29, 2018·Physical Review Letters·Nick HoustonXin Zhang
Mar 7, 2019·Scientific Reports·Man Ho Chan
Nov 24, 2020·Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences·L K Morabito, J Silk
Nov 24, 2020·Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences·Xuelei ChenLi Zhou
Nov 24, 2020·Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences·Jack O Burns
Nov 24, 2020·Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences·Kristian Zarb Adami, I O Farhat
Nov 24, 2020·Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences·Joseph Silk
Jan 30, 2021·Physical Review Letters·Valerie Domcke, Camilo Garcia-Cely
Apr 2, 2021·The Journal of Physical Chemistry. a·Gokul KannanRichard J Saykally
Apr 20, 2021·The American Mineralogist·Robert M Hazen, Shaunna M Morrison
Apr 20, 2021·The American Mineralogist·Robert M HazenAnirudh Prabhu
Jul 17, 2021·Physical Review Letters·Andrea CaputoAlfredo Urbano
Aug 24, 2021·Physical Review Letters·Daniel CarneyJacob M Taylor
Dec 8, 2021·Reports on Progress in Physics·Bernard CarrJun'ichi Yokoyama
Oct 1, 2020··Harry Bevins, Harry Bevins

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