LOFAR Key Science Projects and Science Network in Germany

Transcription

1 LOFAR Key Science Projects and Science Network in Germany Rainer Beck MPIfR Bonn

2 LOFAR A revolution in radio telescope design: Software telescope: no moving parts, no mirrors, simultaneous multi-beaming, low costs Technological challenge: computing power, data transfer and data storage Sensor network for many other scientific applications On-site student training Prototype for the Square Kilometre Array (SKA)

3 LOFAR: Basic Parameters Frequency Range Number of Antennas Polarization Configuration (Phase 1) Low Band: MHz High Band: MHz Low Band: 7700 High Band: 7700 (4x4) Full Stokes Virtual Core: 2x 3072 antennas 32 stations baselines 100 m - 2 km Outside Core: 2x 4320 antennas 45 stations baselines up to 100 km

4 LOFAR Station 96 low-band antennas optimized for MHz 96 high-band tiles 4x4 antennas optimized for ~ MHz

5 Low-band antenna (30-80 MHz)

6 High-band antennas ( MHz)

7 LOFAR: Station Configuration Decision about final configuration in early 2006

8 LOFAR: Station Layout Other sensors Low band High band 60 m 50 m

9 LOFAR: Station Control Unit

10 LOFAR Stations (Phase 1) Virtual Core 32 core stations (2007) 77 stations of full array (2009)

11 LOFAR: Basic Properties

12 LOFAR Performance

13 To reach arcsec resolutions or better, European baselines of several 100 km are necessary

14 International Station Germany 1 at Effelsberg

15 View from the 100m telescope (Photo: Mark Bentum) Germany 1 1

16 International Station Germany 1 at Effelsberg Dec. 2005: Contract with ASTRON Feb. 2006: RFI measurements in LOFAR bands March-May May 2006: Preparation of site June-Aug. 2006: Installation of low-band antennas Sept. 2006: First light End of 2006: First all-sky radio maps Early 2007: Data link to Bonn 2007: High-band antennas 2007: Joint observations with first core stations at Exloo

17 International Station Germany 1 at Effelsberg Problems to be solved in 2006: Power supply Plainness accuracy of the station Limited horizon by hills and trees RFI spectrum Filtering main RFI sources Interference between control station and 100m telescope (both ways) Software and data storage development for stand-alone alone station (survey mode)

18 International Station Germany 2 : Tremsdorf?

19 Garching and Bremen : RFI tests at several sites in 2006

20 Plans for stations in Germany Wanted: 6 At least more stations!

21 LOFAR Science Network in Germany (tentative) Bochum: Galaxies, galactic halos Bonn: Polarization, magnetic fields, Galactic radio emission, radio surveys, AGNs,, jets Bremen: Large-scale radio structures, technology Garching: Cosmology, software infrastructure Hamburg: Radio source surveys Jülich: Supercomputing, GRID Karlsruhe: Supercomputing, GRID Köln: AGNs,, radio galaxies Potsdam: Solar physics, cosmology, GRID

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23 LOFAR Science Network To be discussed: Organization: in Germany GLOW = German Long Wavelength Consortium (sufficient?) Finances: DFG, BMBF, else? Relation to ASTRON Organization of observation programs Access to data

24 Key Science Projects Needed for funding applications, public outreach, and to obtain larger blocks of observation time Requirements: Solving fundamental astrophysical problems Unique science,, only possible with LOFAR Chance for new discoveries General public interest

25 SKA Key Science Testing theories of gravitation and detection of gravitational waves with pulsars The Dark Ages : Epoch of re-ionisation, first black holes The Cradle of Life : Protoplanets, biomolecules, SETI Evolution & large-scale structure : Galaxies, Hubble flow & Dark Energy Cosmic magnetism : RM grid, Faraday tomography, ISM polarimetry

26 LOFAR: Key Science Programs in the Netherlands Cosmology (Univ. Groningen) Epoch of Reionization All-sky surveys (Univ. Leiden) Star forming galaxies, AGN, clusters, etc. Transient detection (Univ. Amsterdam) Everything that bursts and varies Astroparticle physics (Univ. Nijmegen) Direct detection of cosmic rays Cosmic rays & neutrinos impacting the moon

27 Key Science Programs in Germany (to be discussed) Cosmology: Epoch of Reionization and large- scale structures (MPA Garching, Int. Univ. Bremen) (overlaps with Dutch KSP lead by Univ. Groningen) Polarization/magnetic fields (MPIfR Bonn, Univ. Bochum, MPA Garching) Jets (MPIfR Bonn, Univ. Köln, K MPA Garching) Galactic radio emission (MPIfR Bonn) Solar physics (AIP Potsdam)

28 Fluctuations of brightness temperature (Benedetta Ciardi, MPA Garching) The fluctuations are due to variations in HI distribution (density distrib. + ionized regions) S5 L20 Late/early reionization show similar behaviour The peak of the emission is ~10 mk Early reionization,, peaks at ~ 90 MHz, Late reionization,, peaks at ~ 115 MHz

29 LOFAR expected EoR response z~14.5 (~90 MHz) (Valdes et al., in prep) Instrument sampling Gaussian noise Convolution with a Gaussian beam (s=3 arcmin) It will be possible to map the reionization history, especially its latest stages z~10 (~130 MHz)

30 Selected radio continuum surveys (Wolfgang Reich, MPIfR Bonn)

31 Spectral index distributions τ large background absorption τ small blue = flat spectrum red = steep spectrum

32 HII Region W1 = NGC7822 at 850 pc distance Low frequencies: total intensity foreground High frequencies: polarization foreground or background Tomography of Galactic synchrotron emission In future: combining LOFAR + Effelsberg observations 4 x 3.5 mapping : W1 absorption at 22 MHz DRAO W1 at 4.8 GHz Urumqi 4.8 GHz polarization Urumqi 50%

33 All-sky polarization survey (Wolleben, Testori,, Reich & Reich) Preliminary!

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35 Galactic Halos and Magnetic Fields (Rainer Beck, MPIfR; ; Ralf-Jürgen Dettmar,, RUB) NGC5775 (Tüllmann et al. 2000)

36 Geosynchrotron radio emission from extensive air showers (Heino Falcke & Tim Huege,, LOPES collaboration)

37 Spectra of a vertical shower 55 MHz spectra steeper at higher distances 55 MHz: coherence only up to ~ 300 m (vertical showers) 10 MHz: very coherent incoherent regime: need better air shower models (inhomogeneities, pitch angles)

38 Solar radio radiation (Gottfried Mann, AIP) The nonthermal solar radio radiation is a sensitive indicator of solar activity Observatory of Solar Radioastronomy in Tremsdorf ra new spectralpolarimeter ( MHz)

39 Interpretation of solar radio spectra Heliospheric density model (Mann et al., 1999) height from center of the Sun in Mio. km frequency in MHz height velocity frequency drift rate dynamic radio spectrogram height-time time diagram

40 An example of low frequency observations of solar radio radiation type III bursts (electron beams, here km/s) type II bursts (shock waves, here 2100 km/s) LOFAR

41 Next steps ( ) 2007) Formal agreement between institutes to form GLOW (German Long Wavelength Consortium) - Telecon 2006 Jan 18 - Discussions BMBF, Länder, L DFG, etc. about funding possibilities - Meeting with BMBF Jan 2006 Definition of German Key Science Projects - Workshop in March 2006 in Bonn Possible dates: March 8/9, 13/14, or 16/17 Construction of first stations - Effelsberg station in July

42 European Expansion Current discussions: Germany: ~12 stations UK: ~2-3 3 stations Italy: ~2 stations France: ~1 station? Poland: 1 station?

43 Merry Christmas!