Synchrotron Radiation, magnetic fields and cosmic rays

Transcription

1 Synchrotron Radiation, magnetic fields and cosmic rays Giuseppe Di Bernardo 1 in collaboration with Evoli, C., Gaggero, D., Grasso, D. 1 Max Planck Institute for Astrophysics bernardo@mpa-garching.mpg.de Planck Conference Ferrara, December 05, 2014

2 The Synchrotron Emission of the Galaxy quick overview of recent models in view of PLANCK results e.g., the pre-launch PSM, in Delabrouille, J., et al., A&A (2013) They use the template 408 MHz Haslam, and extrapolate in frequency to the Planck ν-channels, assuming (i) a spectral index β s 3.0 (i.e., n epeq9e p, p 3), or (ii) using a β s map derived by combining the 408 MHz and WMAP 23 GHz data (see e.g., Miville-Dechenes et al. 2008) e.g., Fauvet, L., et al., A&A (2012) analytical spatial distribution n epr, zq9 expp r{r scale q{rcoshp2z{z scale qs (Drimmel & Spergel (2001)), with an uniform CRE spectrum and β s 3.45pÑ p 4!!q, and the HAMMURABI code (Waelkens et al., 2009) to compute RMs and synchrotron sky maps. e.g., GALPROP results (Strong, A.W., Orlando, E., Jaffe, T.J., A&A (2011) they based on a physical CRE model, accounting for a double broken power-law source spectrum (w/o extra-component), and uniform diffusion coefficient, and a continuous source distribution (see also Orlando E. contribution in the Poster session) Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 2 / 23

3 The Synchrotron Emission of the Galaxy A Multi-Wavelength Analysis using DRAGON Evoli, C., et al., JCAP (2008); Gaggero, D., et al., PRL (2013) ( Fixing diffusion models against CR nuclei data DRAGON is a new numerical code aiming to solve the diffusion equation of CRs in the Galaxy environment. DRAGON features: position dependent, anisotropic diffusion; independent injection spectra for each nuclear species; interfaced with GAMMASKY to calculate diffuse gamma and synchrotron emissions; interfaced with DarkSUSY to calculate DM contribution... (other major codes, GALPROP, PICARD). The positron-excess... the role of astrophysical galactic extra-component seems more likely than exotic ones (DM annihilation/decay). Plot from Di Bernardo G., et al., See also e.g., Grasso et al., APP 32 (2009), Serpico, P., PRD, 79 (2009), Hooper, D., et al., JCAP 1 (2009): incomplete list of papers! Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 3 / 23

4 The Synchrotron Emission of the Galaxy To Probe the Low Energy Lis of e` ` e using DRAGON + GAMMASKY results from Di Bernardo G., Evoli, C., Gaggero D., Grasso, D., and Maccione, L., JCAP 3 (2013) Sky region: 40 l 340, 10 b T[K] ν[mhz] Radio data GMF - KRA Model KRA Model - w/o break KOL Model - w/o break Below 20 GeV... the e` ` e may not be representative of the physical conditions of the rest of the Galaxy; the solar modulation reshapes the e` ` e Lis ν [MHz] Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 4 / 23

5 The Synchrotron Emission of the Galaxy To Probe the Low Energy Lis of e` ` e using DRAGON + GAMMASKY results from Di Bernardo G., et al., JCAP 3 (2013) Sky region: 40 l 340, 10 b T[K] ν[mhz] Radio data GMF - KRA Model KRA Model - w/o break KOL Model - w/o break KRA Model - only 2 nd Below 100 MHz... the radio spectrum is dominated by secondary e` ` e ; KOL Model - only 2 nd ν [MHz] Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 5 / 23

6 The Synchrotron Emission of the Galaxy To Probe the Low Energy Lis of e` ` e using DRAGON + GAMMASKY results from Di Bernardo G., et al., JCAP 3 (2013) T[K] ν[mhz] Sky region: 40 l 340, 10 b 45 χ 2 KRA = 2.6 χ 2 KOL = 1.9 γ(e ) kra = 1.6 γ(e ) kol = 2.0 Below 100 MHz Radio data GMF Total - KRA Model model Below the 100 radio MHz spectrum... is dominated KRA Total Model - KOL -model w/o break by secondary e` ` e ; the radio spectrum is dominated KOL Model - w/o break 10 5 GMF - KRA Model the ν-radio data are reproduced by secondary e` ` e ; only 2 nd only imposing a sharp break to KRA Model - w/o break the e spectrum below 4GeV KOL KRA Model - only 2 nd (see also e.g., Orlando E., & Strong, A. (2013); 10 5 Bringmann, T. et al (2012); Jaffe et al ν [MHz] (2011)). Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 5 / 23

7 The Synchrotron Emission of the Galaxy To Probe the Low Energy Lis of e` ` e using DRAGON + GAMMASKY results from Di Bernardo G., et al., JCAP 3 (2013) T[K] ν[mhz] Sky region: 40 l 340, 10 b 45 χ 2 KRA = 2.6 χ 2 KOL = 1.9 γ(e ) kra = 1.6 γ(e ) kol = 2.0 a few more details Radio data Total - KRA model regular GMF: B Total - KOL model disc 2µG, B halo 4µG (Pshirkov et al. 2012); 10 5 GMF - KRA Model random MF: KRA Model - w/o break B ranpzq 7.6 ˆ exp p z{z tqµg, KRA Model - only 2 nd (see Han, Ferriere and 10 4 Manchester, 2004); Dpzq9B 1 ran 9 exp pz{ztq. ν [MHz] Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 6 / 23

8 Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 7 / 23 The Synchrotron Emission of the Galaxy The Halo Height: a Cornerstone in Modern Astro-Particle Physics results from Di Bernardo G., et al., JCAP 3 (2013) The magnetic halo height... for a given propagation set up, the synchrotron flux depends only on the random field normalization B ran(z = 0) and on z t, the scale-height of the diffusion region. Bran 2 pz 0q9z MHz dark grey 3σ ÞÑ zt ą 4 kpc; light grey 5σ ÞÑ zt ą 3 kpc; For an exponential profile of the random MF we constraint the halo height using the RM data

9 The Synchrotron Emission of the Galaxy The Latitude Profile: the Global Environment results from Di Bernardo G., et al., JCAP 3 (2013) 10 9 Sky region: 40 l ν = 408 MHz χ 2 zt=2 = 2.8 χ 2 zt=4 = 2.2 χ 2 zt=8 = 0.9 χ 2 zt=16 = 0.5 T[K] ν[mhz] Radio data 40 l 100 Thin halos are excluded at 3 σ... KRA Model, zt = 2 kpc KRA Model, zt = 4 kpc complementary probe of the vertical CRE distribution; KRA Model, zt = 8 kpc KRA set up at different halo KRA Model, zt = 16 kpc heights reproducing well the synchrotron spectrum; latitude [deg] thick halos are favoured! Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 8 / 23

10 How do the Large Scale Structures Influence the Observables? 8 Faucher-Giguère and Kaspi TABLE 2 Spiral Arm Parameters The effects of the spiral arm pattern We live in an inter-arm region: most of the CR sources lie in the arms; high energy CRE cross through larger distances than what expected in a smooth model, where no spiral arm structure is taken into account; more severe energy losses (via IC & Synchrotron): steepening; no steep injection: compatible with 1 st Fermi acceleration mechanism The spiral arm structure...[see e.g., Faucher-Giguere & Kaspi, 2007] Arm Number Name k r0 θ0 (rad) (kpc) (rad) Isolated neutron stars are thought to be formed in core- These mark the deaths of massive, short-lived Population I stars associated with the arms of spiral galaxies. It is thus expected that the birth sites of isolated pulsars will be highly correlated with spiral arms. In fact, Kramer et al. (2003a, see especially their Figure 5) note that following the PM survey, the spiral structure is now clearly vis- birth sites of isolated pulsars ðñ spiral arms; collapse supernova events. pulsars progenitors traced by four major arm centroids: θprq9lnpr{r 0q ` θ 0 1 Norma Carina-Sagittarius Perseus Crux-Scutum Note. The numerical values differ from those given by Wainscoat et al. (1992) due to differences between the coordinate systems used in that paper and in this one. θ =arctan(y/x), and x =(x, y, z) Spiral Arm Structure Fig. 3. Example of a simulated initial distribution of pulsars in the xy plane. Each point represents the birth position of a ible in the distribution Planck Conference in longitudes Ferrara, of December young 05, pulsar 2014 projected onto the plane. The location of the9 Sun / 23 Giuseppe Di Bernardo, in collaboration with Evoli, C.,, Gaggero, D.,, Grasso, D. (MPA)

11 Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 10 / 23 The effects of the spiral arm pattern 2D vs. 3D face-on 1 GeV on the plane Y[kpc] X[kpc] Electron density, Ee =1GeV,z=0 Y[kpc] X[kpc] Electron density, Ee =1GeV,z=0 DRAGON 3D mode (from Gaggero, D., et al. PRL, 111 (2013)) sources distributed in the spiral arms [as in e.g., Faucher-Giguere & Kaspi, 2007; see also Blasi & Amato, JCAP I&II (2012)]; distances between arms» 1 kpc: IC & Synchrotron radiative losses

12 Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 11 / 23 The effects of the spiral arm pattern 2D vs. 3D face-on 100 GeV on the plane Y[kpc] X[kpc] Electron density, Ee =100GeV,z=0 DRAGON 3D mode (from Gaggero, D., et al. PRL, 111 (2013)) sources distributed in the spiral arms [as in e.g., Faucher-Giguere & Kaspi, 2007; see also Blasi & Amato, JCAP I&II (2012)]; distances between arms» 1 kpc: IC & Synchrotron radiative losses; energy losses in the inter-arm region change dramatically the e ` e` spectra above 20 GeV

13 The effects of the spiral arm pattern 2D vs. 3D radial distribution in the z-plane at different energies (1 GeV, 100 GeV and 1 TeV) Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara,C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA)12 / 23

14 The effects of the spiral arm pattern 2D vs. 3D radial distribution at energy of 50 GeV (normalized) electron density no spiral arm pattern; spiral arm pattern profile x [kpc] Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 13 / 23

15 Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 14 / 23 3D Modelling of Pamela and Ams-02 data results from Gaggero, D., et al., PRD 89 (2014) Astrophysical galactic extra-component Γpe q 2.5, and Γpe q 1.7; Wtotppq «10 57, W totpe q «10 55, W totpe q «10 54, W SNR «10 58 rgev{myrs; purple (red): Ecut 10 TeV; blue (orange): Ecut 1 TeV

16 3D Modelling of Synchrotron Ia. 408 MHz Brightness Temperature Maps: Preliminary Results DRAGON + GAMMASKY Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 15 / 23 Brightness ν = 408 MHz Brightness ν = 408 MHz 10 T[K] 1000 Brightness ν = 408 MHz 10 T[K] 1000 Intensity T Ipνqc 2 {2ν 2 k B 10 T[K] 1000 in clockwise order... Drimmel and Spergel (2001); GAMMASKY + CRE w/o arms; GAMMASKY + CRE w/ arms.

17 3D Modelling of Synchrotron Ib. 408 MHz Brightness Temperature Residuals: Preliminary Results DRAGON + GAMMASKY Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 16 / 23 Brightness ν = 408 MHz Brightness ν = 408 MHz 10 T[K] 1000 ν = 408 MHz - full sky 10 T[K] 1000 Residuals -50 T/T [%] 50 S no arms p408q Sarms p408q Sarms p408q

18 3D Modelling of Synchrotron II. Spectral Index Maps from 408 MHz to 23 GHz: Preliminary Results DRAGON + GAMMASKY Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 17 / 23 Synchrotron Spectral index Synchrotron Spectral index βs Synchrotron Spectral index βs Spνq9pν{ν 0 q βs β s logps 23{S 408q βs in clockwise order... CRE by Drimmel and Spergel (2001); GAMMASKY + GAMMASKY CRE w/o arms; GAMMASKY + GAMMASKY CRE w/ arms.

19 3D Modelling of Synchrotron III. The Longitude Profile near the Plane: Preliminary Results DRAGON + GAMMASKY Brightness temperature, T [mk] Sky region: b < ν = 23 GHz WMAP K-band, 9yr 3D KRA model - w/ arms 3D KRA model - w/o arms Drimmel & Spergel longitude [deg] Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 18 / 23

20 3D Modelling of Synchrotron IVa. Polarization Maps at 30 GHz: Preliminary Results DRAGON + GAMMASKY (following the scheme as in HAMMURABI, Waelkens et al., 2009) Synchrotron polarization, Stokes I Synchrotron polarization, Stokes P [mk] 5 Synchrotron polarization, Stokes I D&S vs. 3D CRE ɛ I ɛ K ` ɛ ; ɛ P ɛ K ɛ ; GMF: Pshirkov [mk] 5 Synchrotron polarization, Stokes P [mk] [mk] 5 Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 19 / 23

21 3D Modelling of Synchrotron IVb. Polarization Maps at 30 GHz: Preliminary Results DRAGON + GAMMASKY (following the scheme as in HAMMURABI, Waelkens et al., 2009) Synchrotron polarization, Stokes I Synchrotron polarization, Stokes P [mk] 0.1 Synchrotron polarization, Stokes I D&S vs. 3D CRE ɛ I ɛ K ` ɛ ; ɛ P ɛ K ɛ ; GMF: Spiral [mk] 0.1 Synchrotron polarization, Stokes P [mk] [mk] 0.1 Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 20 / 23

22 Conclusions More effort is needed Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 21 / 23 Multichannel analysis! We exploited the galactic diffuse synchrotron emission as a way to measure the low energy LIS spectrum of CRE; The synchrotron emission, conversely to the common 10 Be{ 9 Be constraint, offers instead a much more direct probe of the magnetic halo height, z t. The spatial and energy distribution of CRE is largely affected by the spiral arm pattern for energy around (and above) 50GeV : that reflects drastically on the angular distribution and the spectral index map of the synchrotron emission; DRAGON: a suitable tool for most CR analysis; GAMMASKY will be soon complete of all relevant components (free-free emission, all Stokes parameters... etc) γ-fermi-lat, CRs and Planck data, simultaneously (see Ensslin s talk).

23 Backup slides Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 22 / 23

24 The Interstellar Medium Turbulence and Transport of CRs Giuseppe Di Bernardo, in collaboration Planck Conference with Evoli, Ferrara, C.,, December Gaggero, 05, 2014 D.,, Grasso, D. (MPA) 23 / 23 The legacy of Kolmogorov pu qu: distorsions of the velocity field (eddies); Onset of turbulence: Re " 1; Energy cascade process: 9ɛ pδu 3 L {Lq; (HD) Kolmogorov s law: WK pkq9 k 5{3 (Alfvnic eddies elongated along the MF); (MHD) Kraichnan s law: WIK pkq9 k 3{2 (fast modes). In the Quasi Linear Theory... kres Ω{vµ; τsca Ω 1 pk res W pk res q{b 2 0 {4πq 1 ; D 1{3vrL {F; F pk res W pk res q{b 2 0 {4πq; ş dkw pkq δb 2 {4π; W pkqdk k 2`δ dk; DpRq 9 R δ ; (HD) Kolmogorov s law: δ 1{3; (MHD) Kraichnan s law: δ 1{2; The ISM is turbulent... on scales ranging from AUs to kpc, with an embedded magnetic field taht influences almost all of its properties. MHD turbulence is accepted to be of key importance for the propagation and acceleration of Cosmic Rays.