Figure 1

Schematic geometry of the symbiotic binary system V407 Cyg. The nova shock wave propagates from the WD star (shock 1) and, as it propagates, starts to partially overtake the RG (shock 2). Particles (electrons, hadrons) are accelerated at the shock. An electron produces a $\gamma$ ray in IC scattering of a soft photon $\epsilon$ (angle of interaction $\beta$). Hadrons produce $\gamma$ rays and neutrinos in collisions with the matter from RG wind.Reuse & Permissions

Figure 2

Optical depths for $\gamma$ rays escaping from vicinity of the RG star. $\gamma$ rays are produced at the distance of $0.1R_{\mathrm{RG}}$ (the dashed curves) or $0.5R_{\mathrm{RG}}$ (the solid curves) from the surface and propagate along the radial direction away from the RG (the thin curves) or perpendicularly to it (the thick lines).Reuse & Permissions

Figure 3

The comparison of the Fermi-LAT $\gamma$-ray average spectral energy distribution (SED) over the period March 10–29, 2010 (black points and upper limits, [2]) with the calculations of the IC $\gamma$-ray spectrum produced by electrons and the TeV $\gamma$-ray spectrum produced in hadronic collisions. Monoenergetic electrons with energy 25 GeV and protons with energy 10 TeV (top panel) or electrons following a spectrum $dN/d{E}_e\propto E_e^{-1.5}\exp (E_e/20\mathrm{GeV})$ and protons with spectrum $dN/d{E}_p\propto E_p^{-1.5}\exp (E_p/8\mathrm{TeV})$ (bottom panel) are accelerated in turbulent medium. Those particles are injected at the distance $0.5R_{\mathrm{RG}}$ from the surface of RG. The thick black line is the total predicted $\gamma$-ray emission composed of three components: IC scattering of the injected electrons (the thin solid line), ${\pi }^0$ decay (the thin dashed line) and IC scattering of the electrons created in ${\pi }^{\pm }$ decay (the dotted line). Thick gray lines show the differential sensitivity (scaled down to 20 hrs) of the MAGIC telescopes (the solid line, [11]) and future CTA observatory (dashed line, [12]). The empty square marker with an arrow is the flux upper limit from VERITAS observations during the period March 19–26, 2010 [6].Reuse & Permissions

Figure 4

$\nu +\overline{\nu }$ emission from hadronic interaction of 10 TeV protons (thin lines) or with spectrum $dN/d{E}_p\propto E_p^{-1.5}\exp (E_p/8\mathrm{TeV})$ (thick lines). Black dashed lines are the muon neutrinos, and black dotted lines are the electron neutrinos. For comparison we show the atmospheric muon neutrino flux in a viewcone of 1° radius with a thick solid gray line [13], and the sensitivity of the IceCube detector (scaled to 14-day observation time) with a dashed gray line (IceCube design report).Reuse & Permissions

Figure 5

SEDs of $\gamma$ rays (the upper panel, like in bottom panel of Fig. 3) and $\nu +\overline{\nu }$ (the lower panel, like in Fig. 4) but for the case of efficient hadronic acceleration in the first order Fermi acceleration process. Injection of electrons $dN/dE\propto E_e^{-1.5}\exp (E_e/20\mathrm{GeV})$ and protons with spectrum $dN/dE\propto E_p^{-1.5}\exp (E_p/80\mathrm{TeV})$ occurs at the distance $0.5R_{\mathrm{RG}}$ from the surface of RG. The total power in relativistic protons is ten-times larger than that one in electrons.Reuse & Permissions