Laurent Denis, Julien Girard, Cyril Tasse the LSS team from Nançay Observatory The consortium FLOW and the LSS teams from Obs. Paris LESIA/ GEPI/LERMA, LPC2E, PRISME, OCA, CEA, IAS, IRAP, CRAL In coll. with IRA/Kharkov
the transverse rod LWA Fork without the transverse rod Antenna Input Impedance Radiation Resistance -600 -400 -200 0 200 400 600 800 1000 X (!1!) LWA Fork with the transverse rod LWA Fork without the transverse rod Antenna Input Impedance Reactance ! ! ! ! type 1!! ! ! ! ! ! type 2 Color legend:! ! Red! ! ! ! ! ! ! Blue Beam Patterns ! ! ! H-plane! ! ! ! ! ! ! E-plane 20 MHz 80 MHz Antenna Input Impedance Option #2: Original development from optimization studies • Numerical simulations carried with NEC (« Numerical Electroma • Simulated variations of radiator geometry and of EM environm antennas. Criteria to define the « best » antenna for the LSS For the mini-array: (with analog phasing) ‛ Smooth beam pattern without gain drops or sidelobes in/at specif ‛ Nearly constant gain from zenith to low elevations (in E & H pla ‛ Quick directivity collapse for elevations ! 30° to reduce RFI con ‛ Broadband characteristics over the [20-80] MHz Considered geometrical parameters oject (96 dual pol) Drift scan compared to sky predictions from LFmap (Polisensky, 2007) LFmap Prototype ! Optimized radiator: LWA-like « thick » V-shape antenna EM Simulation 2 96 High Band Ant. 96 Low Band Ant. 96 Free inputs 96 LBA 30-80 MHz e back-end ow array) layout rences therein
Subatech design Amplificateur «Na Tests labo en cou Tests ciel à veni Une Super Station Lofar à Nançay - Comment? Une antenne active et ..... des câbles (5.5 kms) Un partenaire expérimenté Un amplificateur performant Choix définitif à finaliser
et CT en Hollande, le 17/18 Mai 2011) Mode international Parset file Fichier de configuration lss Parset file lss LCU LOFAR Nançay Hollande LCU - LSS + message ‘start’ Process en attente du message ‘start’ Process en attente du message ‘start’ + message ‘start’ Pointage numérique Pointage analogique L’intégration reste valable même si le soft LOFAR évolue, l’interaction étant faite uniquement par l’échange d’un fichier et d’un ‘top’ départ. Mode standalone Parset file lss LCU LOFAR Nançay LCU - LSS + message ‘start’ Process en attente du message ‘start’ Process en attente du message ‘start’ Pointage numérique Pointage analogique + message ‘start’ Parset file lss Configuration de l’observation
low frequencies, physics of the environment of compact objects, nature of RRATs, giant pulses, possibly planets around pulsars, structure of the ISM via propagation effects → LSS standalone : sensitivity+FoV = discovery machine!, LF LSS science
history of Universe formation (AGN at z<1, star formation in nearby galaxies, clumps up to z=2...) → LSS standalone : sensitivity, calibration → LSS + LOFAR : high-sensitivity VLBI, polarization CMB âges sombres premières sources réionisation premières galaxies LSS science
(ideal in Low-Frequency (LF) radio due to absence of photon noise); time & frequency scales of (dispersed) pulses, nature of emitters (GRB, CR, neutrinos/Moon, discovery...) → LSS standalone + dedicated backend : sensitivity, TAB+ mode, extended TBB, duty cycle LSS science
atmosphere Radio exploration of counterparts of sprites and other TLEs ; origin, distribution / dynamics over center France, time & frequency scales, physical mechanisms → LSS standalone : sensitivity, TAB+ mode, extended TBB, duty cycle LSS science
Solar bursts, Space physics (IP scintillation, RADAR...) structures from decametric observations n. ” - n - of Fig. 1. Example of dynamic spectra from UTR-2 from the time series of July, 13 2002. Examples of the drifting structures studied here are indicated by arrows. 7. Summary and perspectives All the previous examples, based on real observations by using existing radio telescopes, suggest that this still quasi-unexplored part of the spectrum, which lies below 50 MHz; can now be successfully studied with adequate, new and powerful instrumentation. A large part of the nonthermal phenomena in the Universe can research are obvious. Special interest investigations as with existing low-fre missions (WIND, Cassini, etc.), and also ones (STEREO, SIRA, etc.). Finally, one must mention that even instrument on the ground will not help fo lower part of the electromagnetic spec radio frequency range below 10 MHz; w ARTICLE IN PRESS Fig. 11. Drifting ionosphere scintillation and wide-band IPS scintillation on Crab Nebula. A. Lecacheux et al. / Planetary and Space Science 52 (2004) 1357–1374 LSS science
: Feasibility validated 2011/09/12 : Equipex funding application 2012 : Operating prototype with 3 sub-arrays Station Lofar à Nançay - Comment? nique rojet en cours r un financement compatible avec l’ampleur du projet Demande portée par 3 laboratoires Responsables scientifiques: M.Tagger & P.Zarka Responsable technique: L.Denis e Une Super Station Lofar à Nançay - Comment? Une opportunité unique Qui s’articule avec le projet en cours Qui permet d’envisager un financement compatible avec l’ampleur du projet Demande portée par 3 laboratoires Responsables scientifiques: M.Tagger & P.Zarka Responsable technique: L.Denis Dosier EQUIPEX déposé le 12 septembre