Pretraga

Pretražite po imenu i prezimenu autora, mentora, urednika, prevoditelja

Napredna pretraga

Pregled bibliografske jedinice broj: 766632

Initial deep LOFAR observations of epoch of reionization windows. I. The north celestial pole

Yatawatta, S.; de Bruyn, A. G.; Brentjens, M. A.; Labropoulos, P.; Pandey, V. N.; Kazemi, S.; Zaroubi, S.; Koopmans, L. V. E.; Offringa, A. R.; Jelić, Vibor et al.
Initial deep LOFAR observations of epoch of reionization windows. I. The north celestial pole // Astronomy & astrophysics (Berlin), 550 (2013), A136-1 doi:10.1051/0004-6361/201220874 (međunarodna recenzija, članak, znanstveni)

CROSBI ID: 766632 Za ispravke kontaktirajte CROSBI podršku putem web obrasca

Naslov
Initial deep LOFAR observations of epoch of reionization windows. I. The north celestial pole

Autori
Yatawatta, S. ; de Bruyn, A. G. ; Brentjens, M. A. ; Labropoulos, P. ; Pandey, V. N. ; Kazemi, S. ; Zaroubi, S. ; Koopmans, L. V. E. ; Offringa, A. R. ; Jelić, Vibor ; Martinez Rubi, O. ; Veligatla, V. ; Wijnholds, S. J. ; Brouw, W. N. ; Bernardi, G. ; Ciardi, B. ; Daiboo, S. ; Harker, G. ; Mellema, G. ; Schaye, J. ; Thomas, R. ; Vedantham, H. ; Chapman, E. ; Abdalla, F. B. ; Alexov, A. ; Anderson, J. ; Avruch, I. M. ; Batejat, F. ; Bell, M. E. ; Bell, M. R. ; Bentum, M. ; Best, P. ; Bonafede, A. ; Bregman, J. ; Breitling, F. ; van de Brink, R. H. ; Broderick, J. W. ; Brüggen, M. ; Conway, J. ; de Gasperin, F. ; de Geus, E. ; Duscha, S. ; Falcke, H. ; Fallows, R. A. ; Ferrari, C. ; Frieswijk, W. ; Garrett, M. A. ; Griessmeier, J. M. ; Gunst, A. W. ; Hassall, T. E. ; Hessels, J. W. T. ; Hoeft, M. ; Iacobelli, M. ; Juette, E. ; Karastergiou, A. ; Kondratiev, V. I. ; Kramer, M. ; Kuniyoshi, M. ; Kuper, G. ; van Leeuwen, J. ; Maat, P. ; Mann, G. ; McKean, J. P. ; Mevius, M. ; Mol, J. D. ; Munk, H. ; Nijboer, R. ; Noordam, J. E. ; Norden, M. J. ; Orru, E. ; Paas, H. ; Pandey-Pommier, M. ; Pizzo, R. ; Polatidis, A. G. ; Reich, W. ; Röttgering, H. J. A. ; Sluman, J. ; Smirnov, O. ; Stappers, B. ; Steinmetz, M. ; Tagger, M. ; Tang, Y. ; Tasse, C. ; ter Veen, S. ; Vermeulen, R. ; van Weeren, R. J. ; Wise, M. ; Wucknitz, O. ; Zarka, P.

Izvornik
Astronomy & astrophysics (Berlin) (0004-6361) 550 (2013); A136-1

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

Ključne riječi
dark ages; reionization; first stars; instrumentation: interferometers; techniques: interferometric; methods: data analysis

Sažetak
The aim of the LOFAR epoch of reionization (EoR) project is to detect the spectral fluctuations of the redshifted HI 21 cm signal. This signal is weaker by several orders of magnitude than the astrophysical foreground signals and hence, in order to achieve this, very long integrations, accurate calibration for stations and ionosphere and reliable foreground removal are essential. One of the prospective observing windows for the LOFAR EoR project will be centered at the north celestial pole (NCP). We present results from observations of the NCP window using the LOFAR highband antenna (HBA) array in the frequency range 115 MHz to 163 MHz. The data were obtained in April 2011 during the commissioning phase of LOFAR. We used baselines up to about 30 km. The data was processed using a dedicated processing pipeline which is an enhanced version of the standard LOFAR processing pipeline. With about 3 nights, of 6 h each, effective integration we have achieved a noise level of about 100 μJy/PSF in the NCP window. Close to the NCP, the noise level increases to about 180 μJy/PSF, mainly due to additional contamination from unsubtracted nearby sources. We estimate that in our best night, we have reached a noise level only a factor of 1.4 above the thermal limit set by the noise from our Galaxy and the receivers. Our continuum images are several times deeper than have been achieved previously using the WSRT and GMRT arrays. We derive an analytical explanation for the excess noise that we believe to be mainly due to sources at large angular separation from the NCP. We present some details of the data processing challenges and how we solved them. Although many LOFAR stations were, at the time of the observations, in a still poorly calibrated state we have seen no artefacts in our images which would prevent us from producing deeper images in much longer integrations on the NCP window which are about to commence. The limitations present in our current results are mainly due to sidelobe noise from the large number of distant sources, as well as errors related to station beam variations and rapid ionospheric phase fluctuations acting on bright sources. We are confident that we can improve our results with refined processing.

Izvorni jezik
Engleski

Znanstvena područja
Fizika



POVEZANOST RADA

Profili:

Avatar Url Vibor Jelić (autor)

Poveznice na cjeloviti tekst rada:

doi arxiv.org www.aanda.org dx.doi.org

Citiraj ovu publikaciju:

Yatawatta, S.; de Bruyn, A. G.; Brentjens, M. A.; Labropoulos, P.; Pandey, V. N.; Kazemi, S.; Zaroubi, S.; Koopmans, L. V. E.; Offringa, A. R.; Jelić, Vibor et al.
Initial deep LOFAR observations of epoch of reionization windows. I. The north celestial pole // Astronomy & astrophysics (Berlin), 550 (2013), A136-1 doi:10.1051/0004-6361/201220874 (međunarodna recenzija, članak, znanstveni)
Yatawatta, S., de Bruyn, A., Brentjens, M., Labropoulos, P., Pandey, V., Kazemi, S., Zaroubi, S., Koopmans, L., Offringa, A. & Jelić, V. (2013) Initial deep LOFAR observations of epoch of reionization windows. I. The north celestial pole. Astronomy & astrophysics (Berlin), 550, A136-1 doi:10.1051/0004-6361/201220874.
@article{article, author = {Yatawatta, S. and de Bruyn, A. G. and Brentjens, M. A. and Labropoulos, P. and Pandey, V. N. and Kazemi, S. and Zaroubi, S. and Koopmans, L. V. E. and Offringa, A. R. and Jeli\'{c}, Vibor and Martinez Rubi, O. and Veligatla, V. and Wijnholds, S. J. and Brouw, W. N. and Bernardi, G. and Ciardi, B. and Daiboo, S. and Harker, G. and Mellema, G. and Schaye, J. and Thomas, R. and Vedantham, H. and Chapman, E. and Abdalla, F. B. and Alexov, A. and Anderson, J. and Avruch, I. M. and Batejat, F. and Bell, M. E. and Bell, M. R. and Bentum, M. and Best, P. and Bonafede, A. and Bregman, J. and Breitling, F. and van de Brink, R. H. and Broderick, J. W. and Br\"{u}ggen, M. and Conway, J. and de Gasperin, F. and de Geus, E. and Duscha, S. and Falcke, H. and Fallows, R. A. and Ferrari, C. and Frieswijk, W. and Garrett, M. A. and Griessmeier, J. M. and Gunst, A. W. and Hassall, T. E. and Hessels, J. W. T. and Hoeft, M. and Iacobelli, M. and Juette, E. and Karastergiou, A. and Kondratiev, V. I. and Kramer, M. and Kuniyoshi, M. and Kuper, G. and van Leeuwen, J. and Maat, P. and Mann, G. and McKean, J. P. and Mevius, M. and Mol, J. D. and Munk, H. and Nijboer, R. and Noordam, J. E. and Norden, M. J. and Orru, E. and Paas, H. and Pandey-Pommier, M. and Pizzo, R. and Polatidis, A. G. and Reich, W. and R\"{o}ttgering, H. J. A. and Sluman, J. and Smirnov, O. and Stappers, B. and Steinmetz, M. and Tagger, M. and Tang, Y. and Tasse, C. and ter Veen, S. and Vermeulen, R. and van Weeren, R. J. and Wise, M. and Wucknitz, O. and Zarka, P.}, year = {2013}, pages = {A136-1-A136-17}, DOI = {10.1051/0004-6361/201220874}, keywords = {dark ages, reionization, first stars, instrumentation: interferometers, techniques: interferometric, methods: data analysis}, journal = {Astronomy and astrophysics (Berlin)}, doi = {10.1051/0004-6361/201220874}, volume = {550}, issn = {0004-6361}, title = {Initial deep LOFAR observations of epoch of reionization windows. I. The north celestial pole}, keyword = {dark ages, reionization, first stars, instrumentation: interferometers, techniques: interferometric, methods: data analysis} }
@article{article, author = {Yatawatta, S. and de Bruyn, A. G. and Brentjens, M. A. and Labropoulos, P. and Pandey, V. N. and Kazemi, S. and Zaroubi, S. and Koopmans, L. V. E. and Offringa, A. R. and Jeli\'{c}, Vibor and Martinez Rubi, O. and Veligatla, V. and Wijnholds, S. J. and Brouw, W. N. and Bernardi, G. and Ciardi, B. and Daiboo, S. and Harker, G. and Mellema, G. and Schaye, J. and Thomas, R. and Vedantham, H. and Chapman, E. and Abdalla, F. B. and Alexov, A. and Anderson, J. and Avruch, I. M. and Batejat, F. and Bell, M. E. and Bell, M. R. and Bentum, M. and Best, P. and Bonafede, A. and Bregman, J. and Breitling, F. and van de Brink, R. H. and Broderick, J. W. and Br\"{u}ggen, M. and Conway, J. and de Gasperin, F. and de Geus, E. and Duscha, S. and Falcke, H. and Fallows, R. A. and Ferrari, C. and Frieswijk, W. and Garrett, M. A. and Griessmeier, J. M. and Gunst, A. W. and Hassall, T. E. and Hessels, J. W. T. and Hoeft, M. and Iacobelli, M. and Juette, E. and Karastergiou, A. and Kondratiev, V. I. and Kramer, M. and Kuniyoshi, M. and Kuper, G. and van Leeuwen, J. and Maat, P. and Mann, G. and McKean, J. P. and Mevius, M. and Mol, J. D. and Munk, H. and Nijboer, R. and Noordam, J. E. and Norden, M. J. and Orru, E. and Paas, H. and Pandey-Pommier, M. and Pizzo, R. and Polatidis, A. G. and Reich, W. and R\"{o}ttgering, H. J. A. and Sluman, J. and Smirnov, O. and Stappers, B. and Steinmetz, M. and Tagger, M. and Tang, Y. and Tasse, C. and ter Veen, S. and Vermeulen, R. and van Weeren, R. J. and Wise, M. and Wucknitz, O. and Zarka, P.}, year = {2013}, pages = {A136-1-A136-17}, DOI = {10.1051/0004-6361/201220874}, keywords = {dark ages, reionization, first stars, instrumentation: interferometers, techniques: interferometric, methods: data analysis}, journal = {Astronomy and astrophysics (Berlin)}, doi = {10.1051/0004-6361/201220874}, volume = {550}, issn = {0004-6361}, title = {Initial deep LOFAR observations of epoch of reionization windows. I. The north celestial pole}, keyword = {dark ages, reionization, first stars, instrumentation: interferometers, techniques: interferometric, methods: data analysis} }

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

Citati:

    Altmetrijski pokazatelji:


    Podijeli:





    Contrast
    Increase Font
    Decrease Font
    Dyslexic Font
    CROSBI koristi kolačiće (cookies) kako bi poboljšao funkcionalnost stranice.