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Beyond COrE Workshop, Paris Picture: GALFACTS Collaboration Slide 2 Synchrotron Physics (Galactic) Component separation for foregrounds What can COrE tell us that we dont know already from WMAP and Planck? Current ground-based work What about extragalactic low-frequency sources (AGN)? Beyond COrE Workshop, Paris Slide 3 Cosmic ray leptons (electrons, mostly) Origin Propagation Distribution Magnetic Fields (at source) Structure Coherent/Ordered/Random Intensity Propagation effects Faraday Rotation Free-free absorption Beyond COrE Workshop, Paris Slide 4 Supernova remnants prominent in Galactic synchrotron emission Strong shocks Pulsar winds Beyond COrE Workshop, Paris Slide 5 First-order Fermi (e.g. Bell 1978): N(E) E s, I , s = 2 +1 s = (r+2)/(r 1) r = 4 for strong adiabatic shock: s = 2, = 0.5 r 2, > 0.5 r = 7 relativistic shock s = 4/3, = 0.167 (Test particle) Complicated (CR-dominated) r >> 4 cooling shock but fast particles dont see this compression ratio Beyond COrE Workshop, Paris Slide 6 VLA (Dyer et al 2009) Chandra (NASA/CXC) Slide 7 Shock front Radio-X-ray: = 0.50 0.02 Decourchelle et al (2011) X-ray synchrotron = 1.5 Cutoff in spectrum just below X-ray band Highest-energy electrons ~ 100 TeV Thin shock suggests r > 4 Barrel shape: Efficient acceleration at parallel shocks? Contrary to Bell model! SN1006 has radial B-field Beyond COrE Workshop, Paris Slide 8 Significant variation in SNR spectral indices Pulsar Wind nebulae flatter, e.g. Crab = 0.3 Balance between steepening spectrum of old material and injection of new material: Young SNR (+radio SN) have steeper spectra. Beyond COrE Workshop, Paris Slide 9 Low sensitivity in WMAP data at < 1.3 cm gives limited sky coverage Note flat spectrum for Crab nebula Mean P 3.0 Slightly flatter than at lower frequencies. (3.1 in same regions) Kogut et al (2007) claim detection of flattening from P 3.2 to 3.0 from WMAP data alone Use smoothing from 7 to 18 No allowance for pol. bias at 23 GHz: artifact? Beyond COrE Workshop, Paris (3-year WMAP data) Slide 10 External galaxies show SR most intense in spiral arms (M51 extreme case) Highest fractional polarization in interarms Field more ordered Beyond COrE Workshop, Paris Slide 11 Milky Way also has distinct radio spiral arms Consistent with arms in NE2001 model. Cosmic ray analysis suggests CRs very smoothly distributed e.g. Fermi: outer galaxy constant density Major variation in B-field Hammurabi code Waelkens, Jaffe et al. Sun et al (2008) Jaffe et al (2010) Fit: 408 MHz I 23 GHz p Beyond COrE Workshop, Paris NE2001 electron density contours Slide 12 Hammurabi model: B: 2 3 7 G Jaffe et al (2010,2011) Yet another wrinkle: Laing (1980) Not included in published Hammurabi analyses too poorly constrained Beyond COrE Workshop, Paris Slide 13 Ambient spectrum of CRs in ISM is steady state between injection & loss radiative, diffusive, convective Direct measurement in good agreement with inferred spectrum from synchrotron emission (B ~ 6 G) Detailed modelling suggests injection spectrum with several breaks, very hard at low frequency (s ~ 1.6) C.f. Orlando, Strong & Jaffe (2011) Jaffe et al 2011: E 3 scaling GALPROP prediction fitted to synchrotron data vs local e spectrum. Beyond COrE Workshop, Paris Slide 14 408 MHz I + 23 GHz P Minimum intensity at mid latitudes Synchrotron monopole: Cosec|b|fit to Haslam map: zero level = 9.8 K (N), 10.1 K (S) But already zeroed to 3 K Would give negative intensity at faintest points cf ARCADE2 Isotropic component! Local bubble or halo? Beyond COrE Workshop, Paris Slide 15 On large scale mostly dominated by coherent structures Loops (local) Fan (c. 1 kpc) SNRs Not a lot of scope for meaningful statistical analysis higher resolution needed! Slide 16 Beyond COrE Workshop, Paris Only Loop I and top half of Loop III clear ???? ? Slide 17 Polarization well organized across NGP Fractional polarization low outside Spur: ~ 10% Complex structure along LOS Field in Spur follows outside field Bright rim effect? Beyond COrE Workshop, Paris Slide 18 Needed to do foreground science as well as for CMB! Since Planck designed, Anomalous Microwave Emission discovered Significant contributor 10-60 GHz Quite variable spectrum, peak 20- 40 GHz Beyond COrE Workshop, Paris Slide 19 Synchro Free-free Spinning dust Thermal dust CMB RMS @ 1 resolution Beyond COrE Workshop, Paris Slide 20 rms Q,U @ 1 E B, r = 0.1 3.4% anomalous dust 10% thermal dust artefacts at 100 & 217 GHz from CO lines QUIJOTE Slide 21 Planck, after subtraction of templates for all major components NB: template fit pretty good! ESA press release Feb 2012 Beyond COrE Workshop, Paris Fermi, E > 10 GeV NASA press release Jan 2012 Slide 22 Existence of haze conclusively demonstrated Interpretation: Two components, = 0.5 and = 1 Implicit in template method Region with single unusual = 0.7 Very hard to distinguish without ultra-precise measurements Illustration assumes 2% errors for WMAP/Planck, except at > 50 GHz Actual errors dominated by residuals from other foregrounds Beyond COrE Workshop, Paris Slide 23 Synchrotron spectra are very smooth Monoenergetic kernel Nearly power-law electron distribution Similarly free-free Spinning dust Thermal dust Synchrotron spectrum of mono- energetic electrons Black body Beyond COrE Workshop, Paris Slide 24 Power law is just an approximation but a good one The best- measured synchrotron sources are well fit by a 2 nd -order log-log polynomial over 2 decades of frequency Beyond COrE Workshop, Paris Slide 25 Fermi shows electron spectrum really is smooth NB: Emission frequency E Stay tuned for AMS2 results Departures from power law expected at high E where propagtion time from nearest source ~ radiative lifetime ~50 TeV? Optical band! Assumes 6 G Jaffe et al (2011) Slide 26 More frequencies: Maybe we will have more frequency points than parameters to fit! Better-defined frequencies because bands are narrower Including significantly smaller colour correction Hopefully more resources devoted to getting accurate bands in pre-launch calibration High sensitivity: component discrimination depends on differences between adjacent bands Easy to run out of SNR Especially if bands are close together BUT fundamentally, with all components smooth, subdividing bands rapidly stops giving new information Very likely CMB+AME+Synch + Free-Free + dust is fundamentally ambiguous NB: monopole uncertainty doesnt help. Beyond COrE Workshop, Paris Slide 27 Many surveys exist but quality uneven Strong et al (2011) for an up-to-date list Complications: Below 300 MHz: free- free absorption, especially in the plane Above 1 GHz: free- free emission Below 5 GHz Faraday rotation Above 10 GHz: AME Beyond COrE Workshop, Paris Guzmn et al 2011 Slide 28 Dipole arrays Japan (Maeda et al 1999) Chile (Alvarez et al 1997) Merged map Guzmn et al (2011) Spectral index vs 408 MHz Beyond COrE Workshop, Paris Slide 29 Replacement for DRAO/Villa Elisa 21 cm survey Fully sampled, 30 beam 1.3 -1.8 GHz 2048 channels for RM Synthesis I as well as Q U South from Parkes STAPS (PI Haverkorn) Also low band: 300 - 900 MHz. Beyond COrE Workshop, Paris Wolleben et al (2010, ApJL) Slide 30 Continuum Transit Survey with Arecibo L-Band Feed Array 32% of sky 3 arcmin beam 300 MHz 2048 channels Final maps will use GMIMS to recover large-scale structure Beyond COrE Workshop, Paris GALFACTS fields overlaid on Stockert Survey Slide 31 2.3 GHz Southern-sky polarization survey with Parkes 9 beam Data collected, processing under way Much less depolarized than 21 cm. Figs from Carretti (2011) ATNF Newsletter Beyond COrE Workshop, Paris Slide 32 5 GHz all-sky survey IQU, 48 beam Planck-like pseudo- correlation total power receiver combined with correlation polarimeter. Telescope optimised to minimise sidelobes Owens Valley (north) Karoo (south) Beyond COrE Workshop, Paris Slide 33 QUI JOint TEnerife experiment 11-30 GHz Telescope recently installed on Teide Aim to map ~ of sky at 15 GHz in full polarization Beyond COrE Workshop, Paris Slide 34 Prior to WMAP, there were no large-area surveys from 6 cm to 100 m Previously, pioneering this much new territory has yield unexpected phenomena quasars, pulsars, X-ray binaries, Gamma-ray bursts, ULIRGs But WMAP and Planck LFI ERCSC show only expected blazar-type AGN HFI point sources are also the expected SMGs Deeper surveys @ < 70 GHz with COrE-sized telescope will rapidly hit the confusion limit LFI close to confusion at 30 GHz Ground-based surveys already far deeper and SKA is coming Beyond COrE Workshop, Paris Slide 35 Old questions: What is the central engine? How does it make relativistic jets? How do jets propagate to Mpc scales? How does the AGN population evolve cosmologically? New questions What do AGN do to their environment? Regulate cluster cooling? Provide entropy floor? Use as Faraday probes to study growth of cosmic magnetic fields Beyond COrE Workshop, Paris Slide 36 Slide 37 Guidetta et al (2011) Beyond COrE Workshop, Paris Slide 38 Slide 39 Radio/X-ray interactions to probe dynamics VLBI movies to probe dynamics Variability Large samples for statistics/rare cases Polarization structure and wavelength- dependence to probe local and line-of- sight Faraday rotation Must be spatially resolved! Beyond COrE Workshop, Paris Slide 40 ALMA JVLA GBT Meerkat / SKA LMT ASKAP Slide 41 Beyond COrE Workshop, Paris Slide 42 COrE features: many bands, high sensitivity, narrow(er) bands will all help untangle low frequency foregrounds If frequency coverage extends 100 GHz and we avoid spectral lines! BUT problem is fundamentally insoluable: not clear whether approximate solutions can be good enough to give interasting astrophysics. COrE band is not of critical interest for synchrotron radiation COrE measurements of AGN are not competitive with ground-based instruments. Beyond COrE Workshop, Paris