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Pregled bibliografske jedinice broj: 1052936

Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR

Mertens, F. G.; Mevius, M.; Koopmans, L. V. E.; Offringa, A. R.; Mellema, G.; Zaroubi, S.; Brentjens, M. A.; Gan, H.; Gehlot, B. K.; Pandey, V. N. et al.
Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR // Monthly notices of the Royal Astronomical Society, 493 (2020), 2; 1662-1685 doi:10.1093/mnras/staa327 (međunarodna recenzija, članak, znanstveni)

CROSBI ID: 1052936 Za ispravke kontaktirajte CROSBI podršku putem web obrasca

Naslov
Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR

Autori
Mertens, F. G. ; Mevius, M. ; Koopmans, L. V. E. ; Offringa, A. R. ; Mellema, G. ; Zaroubi, S. ; Brentjens, M. A. ; Gan, H. ; Gehlot, B. K. ; Pandey, V. N. ; Sardarabadi, A. M. ; Vedantham, H. K. ; Yatawatta, S. ; Asad, K. M. B. ; Ciardi, B. ; Chapman, E. ; Gazagnes, S. ; Ghara, R. ; Ghosh, A. ; Giri, S. K. ; Iliev, I. T. ; Jelić, Vibor ; Kooistra, R. ; Mondal, R. ; Schaye, J. ; Silva, M. B.

Izvornik
Monthly notices of the Royal Astronomical Society (0035-8711) 493 (2020), 2; 1662-1685

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
methods: data analysis ; techniques: interferometric ; dark ages ; reionization ; first stars ; cosmology: observations ; Astrophysics : Cosmology and Nongalactic Astrophysics

Sažetak
A new upper limit on the 21 cm signal power spectrum at a redshift of z ≈ 9.1 is presented, based on 141 h of data obtained with the Low-Frequency Array (LOFAR). The analysis includes significant improvements in spectrally smooth gain-calibration, Gaussian Process Regression (GPR) foreground mitigation and optimally weighted power spectrum inference. Previously seen ‘excess power’ due to spectral structure in the gain solutions has markedly reduced but some excess power still remains with a spectral correlation distinct from thermal noise. This excess has a spectral coherence scale of 0.25–0.45 MHz and is partially correlated between nights, especially in the foreground wedge region. The correlation is stronger between nights covering similar local sidereal times. A best 2-σ upper limit of Δ221<(73)2mK2 at k=0.075hcMpc−1 is found, an improvement by a factor ≈8 in power compared to the previously reported upper limit. The remaining excess power could be due to residual foreground emission from sources or diffuse emission far away from the phase centre, polarization leakage, chromatic calibration errors, ionosphere, or low-level radiofrequency interference. We discuss future improvements to the signal processing chain that can further reduce or even eliminate these causes of excess power.

Izvorni jezik
Engleski

Znanstvena područja
Fizika



POVEZANOST RADA

Projekti:
HRZZ-IP-2018-01-2889 - Razumijevanje zračenja na niskim radio frekvencijama: ususret novoj generaciji radio teleskopa (LowFreqCRO) (Jelić, Vibor, HRZZ - 2018-01) ( CroRIS)

Ustanove:
Institut "Ruđer Bošković", Zagreb

Profili:

Avatar Url Vibor Jelić (autor)

Poveznice na cjeloviti tekst rada:

doi arxiv.org fulir.irb.hr doi.org academic.oup.com

Citiraj ovu publikaciju:

Mertens, F. G.; Mevius, M.; Koopmans, L. V. E.; Offringa, A. R.; Mellema, G.; Zaroubi, S.; Brentjens, M. A.; Gan, H.; Gehlot, B. K.; Pandey, V. N. et al.
Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR // Monthly notices of the Royal Astronomical Society, 493 (2020), 2; 1662-1685 doi:10.1093/mnras/staa327 (međunarodna recenzija, članak, znanstveni)
Mertens, F., Mevius, M., Koopmans, L., Offringa, A., Mellema, G., Zaroubi, S., Brentjens, M., Gan, H., Gehlot, B. & Pandey, V. (2020) Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR. Monthly notices of the Royal Astronomical Society, 493 (2), 1662-1685 doi:10.1093/mnras/staa327.
@article{article, author = {Mertens, F. G. and Mevius, M. and Koopmans, L. V. E. and Offringa, A. R. and Mellema, G. and Zaroubi, S. and Brentjens, M. A. and Gan, H. and Gehlot, B. K. and Pandey, V. N. and Sardarabadi, A. M. and Vedantham, H. K. and Yatawatta, S. and Asad, K. M. B. and Ciardi, B. and Chapman, E. and Gazagnes, S. and Ghara, R. and Ghosh, A. and Giri, S. K. and Iliev, I. T. and Jeli\'{c}, Vibor and Kooistra, R. and Mondal, R. and Schaye, J. and Silva, M. B.}, year = {2020}, pages = {1662-1685}, DOI = {10.1093/mnras/staa327}, keywords = {methods: data analysis, techniques: interferometric, dark ages, reionization, first stars, cosmology: observations, Astrophysics : Cosmology and Nongalactic Astrophysics}, journal = {Monthly notices of the Royal Astronomical Society}, doi = {10.1093/mnras/staa327}, volume = {493}, number = {2}, issn = {0035-8711}, title = {Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR}, keyword = {methods: data analysis, techniques: interferometric, dark ages, reionization, first stars, cosmology: observations, Astrophysics : Cosmology and Nongalactic Astrophysics} }
@article{article, author = {Mertens, F. G. and Mevius, M. and Koopmans, L. V. E. and Offringa, A. R. and Mellema, G. and Zaroubi, S. and Brentjens, M. A. and Gan, H. and Gehlot, B. K. and Pandey, V. N. and Sardarabadi, A. M. and Vedantham, H. K. and Yatawatta, S. and Asad, K. M. B. and Ciardi, B. and Chapman, E. and Gazagnes, S. and Ghara, R. and Ghosh, A. and Giri, S. K. and Iliev, I. T. and Jeli\'{c}, Vibor and Kooistra, R. and Mondal, R. and Schaye, J. and Silva, M. B.}, year = {2020}, pages = {1662-1685}, DOI = {10.1093/mnras/staa327}, keywords = {methods: data analysis, techniques: interferometric, dark ages, reionization, first stars, cosmology: observations, Astrophysics : Cosmology and Nongalactic Astrophysics}, journal = {Monthly notices of the Royal Astronomical Society}, doi = {10.1093/mnras/staa327}, volume = {493}, number = {2}, issn = {0035-8711}, title = {Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR}, keyword = {methods: data analysis, techniques: interferometric, dark ages, reionization, first stars, cosmology: observations, Astrophysics : Cosmology and Nongalactic Astrophysics} }

Časopis indeksira:


  • Current Contents Connect (CCC)
  • Web of Science Core Collection (WoSCC)
    • Science Citation Index Expanded (SCI-EXP)
    • SCI-EXP, SSCI i/ili A&HCI
  • Scopus

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