Lunar occultation of the diffuse radio sky: LOFAR measurements between 35 and 80 MHz

H K Vedantham; L V E Koopmans; A G de Bruyn; S J Wijnholds; M Brentjens; F B Abdalla; K M B Asad; G Bernardi; S Bus; E Chapman; B Ciardi; S Daiboo; E R Fernandez; A Ghosh; G Harker; V Jelic; H Jensen; S Kazemi; P Lambropoulos; O Martinez-Rubi; G Mellema; M Mevius; A R Offringa; V N Pandey; A H Patil; R M Thomas; V Veligatla; S Yatawatta; S Zaroubi; J Anderson; A Asgekar; M E Bell; M J Bentum; P Best; A Bonafede; F Breitling; J Broderick; M Brüggen; H R Butcher; A Corstanje; F de Gasperin; E de Geus; A Deller; S Duscha; J Eislöffel; D Engels; H Falcke; R A Fallows; R Fender; C Ferrari; W Frieswijk; Michael Garrett; J Grießmeier; A W Gunst; T E Hassall; G Heald; M Hoeft; J Hörandel; M Iacobelli; E Juette; V I Kondratiev; M Kuniyoshi; G Kuper; G Mann; S Markoff; R McFadden; D McKay-Bukowski; J P McKean; D D Mulcahy; H Munk; A Nelles; M J Norden; E Orru; M Pandey-Pommier; R Pizzo; A G Polatidis; W Reich; A Renting; H Röttgering; D Schwarz; A Shulevski; O Smirnov; B W Stappers; M Steinmetz; J Swinbank; M Tagger; Y Tang; C Tasse; S ter Veen; S Thoudam; C Toribio; C Vocks; M W Wise; O Wucknitz; P Zarka

doi:10.1093/mnras/stv746

Lunar occultation of the diffuse radio sky: LOFAR measurements between 35 and 80 MHz

H K Vedantham, L V E Koopmans, A G de Bruyn, S J Wijnholds, M Brentjens, F B Abdalla, K M B Asad, G Bernardi, S Bus, E Chapman, B Ciardi, S Daiboo, E R Fernandez, A Ghosh, G Harker, V Jelic, H Jensen, S Kazemi, P Lambropoulos, O Martinez-RubiG Mellema, M Mevius, A R Offringa, V N Pandey, A H Patil, R M Thomas, V Veligatla, S Yatawatta, S Zaroubi, J Anderson, A Asgekar, M E Bell, M J Bentum, P Best, A Bonafede, F Breitling, J Broderick, M Brüggen, H R Butcher, A Corstanje, F de Gasperin, E de Geus, A Deller, S Duscha, J Eislöffel, D Engels, H Falcke, R A Fallows, R Fender, C Ferrari, W Frieswijk, Michael Garrett, J Grießmeier, A W Gunst, T E Hassall, G Heald, M Hoeft, J Hörandel, M Iacobelli, E Juette, V I Kondratiev, M Kuniyoshi, G Kuper, G Mann, S Markoff, R McFadden, D McKay-Bukowski, J P McKean, D D Mulcahy, H Munk, A Nelles, M J Norden, E Orru, M Pandey-Pommier, R Pizzo, A G Polatidis, W Reich, A Renting, H Röttgering, D Schwarz, A Shulevski, O Smirnov, B W Stappers, M Steinmetz, J Swinbank, M Tagger, Y Tang, C Tasse, S ter Veen, S Thoudam, C Toribio, C Vocks, M W Wise, O Wucknitz, P Zarka

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Abstract

We present radio observations of the Moon between 35 and 80 MHz to demonstrate a novel technique of interferometrically measuring large-scale diffuse emission extending far beyond the primary beam (global signal) for the first time. In particular, we show that (i) the Moon appears as a negative-flux source at frequencies 35 <ν <80 MHz since it is `colder' than the diffuse Galactic background it occults, (ii) using the (negative) flux of the lunar disc, we can reconstruct the spectrum of the diffuse Galactic emission with the lunar thermal emission as a reference, and (iii) that reflected RFI (radio-frequency interference) is concentrated at the centre of the lunar disc due to specular nature of reflection, and can be independently measured. Our RFI measurements show that (i) Moon-based Cosmic Dawn experiments must design for an Earth-isolation of better than 80 dB to achieve an RFI temperature 2 at 800 km height, or 15 m² at 400 km height. Currently, our diffuse background spectrum is limited by sidelobe confusion on short baselines (10-15 per cent level). Further refinement of our technique may yield constraints on the redshifted global 21 cm signal from Cosmic Dawn (40 > z > 12) and the Epoch of Reionization (12 > z > 5).

Original language	English
Pages (from-to)	2291-2305
Number of pages	15
Journal	Monthly Notices of the Royal Astronomical Society
Volume	450
DOIs	https://doi.org/10.1093/mnras/stv746
Publication status	Published - 2015

Keywords

methods: observational
techniques: interferometric
Moon
dark ages
reionization
first stars

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10.1093/mnras/stv746

stv746Final published version, 1.45 MB

http://adsabs.harvard.edu/abs/2015MNRAS.450.2291V

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Vedantham, H. K., Koopmans, L. V. E., de Bruyn, A. G., Wijnholds, S. J., Brentjens, M., Abdalla, F. B., Asad, K. M. B., Bernardi, G., Bus, S., Chapman, E., Ciardi, B., Daiboo, S., Fernandez, E. R., Ghosh, A., Harker, G., Jelic, V., Jensen, H., Kazemi, S., Lambropoulos, P., ... Zarka, P. (2015). Lunar occultation of the diffuse radio sky: LOFAR measurements between 35 and 80 MHz. Monthly Notices of the Royal Astronomical Society, 450, 2291-2305. https://doi.org/10.1093/mnras/stv746

@article{950ffde591af44c9a768632d8f38ae82,

title = "Lunar occultation of the diffuse radio sky: LOFAR measurements between 35 and 80 MHz",

abstract = "We present radio observations of the Moon between 35 and 80 MHz to demonstrate a novel technique of interferometrically measuring large-scale diffuse emission extending far beyond the primary beam (global signal) for the first time. In particular, we show that (i) the Moon appears as a negative-flux source at frequencies 35 <ν <80 MHz since it is `colder' than the diffuse Galactic background it occults, (ii) using the (negative) flux of the lunar disc, we can reconstruct the spectrum of the diffuse Galactic emission with the lunar thermal emission as a reference, and (iii) that reflected RFI (radio-frequency interference) is concentrated at the centre of the lunar disc due to specular nature of reflection, and can be independently measured. Our RFI measurements show that (i) Moon-based Cosmic Dawn experiments must design for an Earth-isolation of better than 80 dB to achieve an RFI temperature 2 at 800 km height, or 15 m2 at 400 km height. Currently, our diffuse background spectrum is limited by sidelobe confusion on short baselines (10-15 per cent level). Further refinement of our technique may yield constraints on the redshifted global 21 cm signal from Cosmic Dawn (40 > z > 12) and the Epoch of Reionization (12 > z > 5).",

keywords = "methods: observational, techniques: interferometric, Moon, dark ages, reionization, first stars",

author = "Vedantham, {H K} and Koopmans, {L V E} and {de Bruyn}, {A G} and Wijnholds, {S J} and M Brentjens and Abdalla, {F B} and Asad, {K M B} and G Bernardi and S Bus and E Chapman and B Ciardi and S Daiboo and Fernandez, {E R} and A Ghosh and G Harker and V Jelic and H Jensen and S Kazemi and P Lambropoulos and O Martinez-Rubi and G Mellema and M Mevius and Offringa, {A R} and Pandey, {V N} and Patil, {A H} and Thomas, {R M} and V Veligatla and S Yatawatta and S Zaroubi and J Anderson and A Asgekar and Bell, {M E} and Bentum, {M J} and P Best and A Bonafede and F Breitling and J Broderick and M Br{\"u}ggen and Butcher, {H R} and A Corstanje and {de Gasperin}, F and {de Geus}, E and A Deller and S Duscha and J Eisl{\"o}ffel and D Engels and H Falcke and Fallows, {R A} and R Fender and C Ferrari and W Frieswijk and Michael Garrett and J Grie{\ss}meier and Gunst, {A W} and Hassall, {T E} and G Heald and M Hoeft and J H{\"o}randel and M Iacobelli and E Juette and Kondratiev, {V I} and M Kuniyoshi and G Kuper and G Mann and S Markoff and R McFadden and D McKay-Bukowski and McKean, {J P} and Mulcahy, {D D} and H Munk and A Nelles and Norden, {M J} and E Orru and M Pandey-Pommier and R Pizzo and Polatidis, {A G} and W Reich and A Renting and H R{\"o}ttgering and D Schwarz and A Shulevski and O Smirnov and Stappers, {B W} and M Steinmetz and J Swinbank and M Tagger and Y Tang and C Tasse and {ter Veen}, S and S Thoudam and C Toribio and C Vocks and Wise, {M W} and O Wucknitz and P Zarka",

year = "2015",

doi = "10.1093/mnras/stv746",

language = "English",

volume = "450",

pages = "2291--2305",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "1365-2966",

publisher = "Oxford University Press",

}

Vedantham, HK, Koopmans, LVE, de Bruyn, AG, Wijnholds, SJ, Brentjens, M, Abdalla, FB, Asad, KMB, Bernardi, G, Bus, S, Chapman, E, Ciardi, B, Daiboo, S, Fernandez, ER, Ghosh, A, Harker, G, Jelic, V, Jensen, H, Kazemi, S, Lambropoulos, P, Martinez-Rubi, O, Mellema, G, Mevius, M, Offringa, AR, Pandey, VN, Patil, AH, Thomas, RM, Veligatla, V, Yatawatta, S, Zaroubi, S, Anderson, J, Asgekar, A, Bell, ME, Bentum, MJ, Best, P, Bonafede, A, Breitling, F, Broderick, J, Brüggen, M, Butcher, HR, Corstanje, A, de Gasperin, F, de Geus, E, Deller, A, Duscha, S, Eislöffel, J, Engels, D, Falcke, H, Fallows, RA, Fender, R, Ferrari, C, Frieswijk, W, Garrett, M, Grießmeier, J, Gunst, AW, Hassall, TE, Heald, G, Hoeft, M, Hörandel, J, Iacobelli, M, Juette, E, Kondratiev, VI, Kuniyoshi, M, Kuper, G, Mann, G, Markoff, S, McFadden, R, McKay-Bukowski, D, McKean, JP, Mulcahy, DD, Munk, H, Nelles, A, Norden, MJ, Orru, E, Pandey-Pommier, M, Pizzo, R, Polatidis, AG, Reich, W, Renting, A, Röttgering, H, Schwarz, D, Shulevski, A, Smirnov, O, Stappers, BW, Steinmetz, M, Swinbank, J, Tagger, M, Tang, Y, Tasse, C, ter Veen, S, Thoudam, S, Toribio, C, Vocks, C, Wise, MW, Wucknitz, O & Zarka, P 2015, 'Lunar occultation of the diffuse radio sky: LOFAR measurements between 35 and 80 MHz', Monthly Notices of the Royal Astronomical Society, vol. 450, pp. 2291-2305. https://doi.org/10.1093/mnras/stv746

TY - JOUR

T1 - Lunar occultation of the diffuse radio sky: LOFAR measurements between 35 and 80 MHz

AU - Vedantham, H K

AU - Koopmans, L V E

AU - de Bruyn, A G

AU - Wijnholds, S J

AU - Brentjens, M

AU - Abdalla, F B

AU - Asad, K M B

AU - Bernardi, G

AU - Bus, S

AU - Chapman, E

AU - Ciardi, B

AU - Daiboo, S

AU - Fernandez, E R

AU - Ghosh, A

AU - Harker, G

AU - Jelic, V

AU - Jensen, H

AU - Kazemi, S

AU - Lambropoulos, P

AU - Martinez-Rubi, O

AU - Mellema, G

AU - Mevius, M

AU - Offringa, A R

AU - Pandey, V N

AU - Patil, A H

AU - Thomas, R M

AU - Veligatla, V

AU - Yatawatta, S

AU - Zaroubi, S

AU - Anderson, J

AU - Asgekar, A

AU - Bell, M E

AU - Bentum, M J

AU - Best, P

AU - Bonafede, A

AU - Breitling, F

AU - Broderick, J

AU - Brüggen, M

AU - Butcher, H R

AU - Corstanje, A

AU - de Gasperin, F

AU - de Geus, E

AU - Deller, A

AU - Duscha, S

AU - Eislöffel, J

AU - Engels, D

AU - Falcke, H

AU - Fallows, R A

AU - Fender, R

AU - Ferrari, C

AU - Frieswijk, W

AU - Garrett, Michael

AU - Grießmeier, J

AU - Gunst, A W

AU - Hassall, T E

AU - Heald, G

AU - Hoeft, M

AU - Hörandel, J

AU - Iacobelli, M

AU - Juette, E

AU - Kondratiev, V I

AU - Kuniyoshi, M

AU - Kuper, G

AU - Mann, G

AU - Markoff, S

AU - McFadden, R

AU - McKay-Bukowski, D

AU - McKean, J P

AU - Mulcahy, D D

AU - Munk, H

AU - Nelles, A

AU - Norden, M J

AU - Orru, E

AU - Pandey-Pommier, M

AU - Pizzo, R

AU - Polatidis, A G

AU - Reich, W

AU - Renting, A

AU - Röttgering, H

AU - Schwarz, D

AU - Shulevski, A

AU - Smirnov, O

AU - Stappers, B W

AU - Steinmetz, M

AU - Swinbank, J

AU - Tagger, M

AU - Tang, Y

AU - Tasse, C

AU - ter Veen, S

AU - Thoudam, S

AU - Toribio, C

AU - Vocks, C

AU - Wise, M W

AU - Wucknitz, O

AU - Zarka, P

PY - 2015

Y1 - 2015

N2 - We present radio observations of the Moon between 35 and 80 MHz to demonstrate a novel technique of interferometrically measuring large-scale diffuse emission extending far beyond the primary beam (global signal) for the first time. In particular, we show that (i) the Moon appears as a negative-flux source at frequencies 35 <ν <80 MHz since it is `colder' than the diffuse Galactic background it occults, (ii) using the (negative) flux of the lunar disc, we can reconstruct the spectrum of the diffuse Galactic emission with the lunar thermal emission as a reference, and (iii) that reflected RFI (radio-frequency interference) is concentrated at the centre of the lunar disc due to specular nature of reflection, and can be independently measured. Our RFI measurements show that (i) Moon-based Cosmic Dawn experiments must design for an Earth-isolation of better than 80 dB to achieve an RFI temperature 2 at 800 km height, or 15 m2 at 400 km height. Currently, our diffuse background spectrum is limited by sidelobe confusion on short baselines (10-15 per cent level). Further refinement of our technique may yield constraints on the redshifted global 21 cm signal from Cosmic Dawn (40 > z > 12) and the Epoch of Reionization (12 > z > 5).

AB - We present radio observations of the Moon between 35 and 80 MHz to demonstrate a novel technique of interferometrically measuring large-scale diffuse emission extending far beyond the primary beam (global signal) for the first time. In particular, we show that (i) the Moon appears as a negative-flux source at frequencies 35 <ν <80 MHz since it is `colder' than the diffuse Galactic background it occults, (ii) using the (negative) flux of the lunar disc, we can reconstruct the spectrum of the diffuse Galactic emission with the lunar thermal emission as a reference, and (iii) that reflected RFI (radio-frequency interference) is concentrated at the centre of the lunar disc due to specular nature of reflection, and can be independently measured. Our RFI measurements show that (i) Moon-based Cosmic Dawn experiments must design for an Earth-isolation of better than 80 dB to achieve an RFI temperature 2 at 800 km height, or 15 m2 at 400 km height. Currently, our diffuse background spectrum is limited by sidelobe confusion on short baselines (10-15 per cent level). Further refinement of our technique may yield constraints on the redshifted global 21 cm signal from Cosmic Dawn (40 > z > 12) and the Epoch of Reionization (12 > z > 5).

KW - methods: observational

KW - techniques: interferometric

KW - Moon

KW - dark ages

KW - reionization

KW - first stars

U2 - 10.1093/mnras/stv746

DO - 10.1093/mnras/stv746

M3 - Article

SN - 1365-2966

VL - 450

SP - 2291

EP - 2305

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

ER -

Lunar occultation of the diffuse radio sky: LOFAR measurements between 35 and 80 MHz

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Keywords

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