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High-Energy Emission from Young and Massive Stellar Objects

High-Energy Emission from Young and Massive Stellar Objects. Gustavo E. Romero IAR-CONICET romero@iar-conicet.gov.ar. Felix Aharonian’s Workshop November 7 th , 2012. What are the contents of star-forming regions ?.

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High-Energy Emission from Young and Massive Stellar Objects

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  1. High-Energy Emission from Young and Massive Stellar Objects Gustavo E. Romero IAR-CONICET romero@iar-conicet.gov.ar Felix Aharonian’s Workshop November 7th, 2012

  2. What are thecontents of star-formingregions? • Gas (Hayakawa 1952, Morrison 1958, Aharonian & Atoyan 1996). • Young, massivestarswithwindscollectiveeffects(Bykov & Fleishman 1992, Romero & Torres 2003, Torres et al. 2004, Parizot et al. 2004, Bykov: yesterday, etc). • Young pulsars. • SNRs (yesterday’stalks). • Collidingwindbinaries(Eichler & Usov 1993, Benaglia & Romero 2003, Pittard & Daugherty 2006). • Accretingsources(Paredes, Mirabel, Bosch-Ramon – thisworkshop). • FORMING MASSIVE STARS. • RUNAWAY MASSIVE STARS.

  3. Massivestars are formed in massive and dense cores of giant molecular clouds. Thecores are theresult of thegravitationalfragmentation of thecloud Themechanism of massivestarformationisstillmatter of debate. There are twomaindifferentscenarios: accretion and coalescence .

  4. Herbig-Haro objects HH49-50

  5. HH 80-81: a partiallyembeddedmassiveprotostellarsystem Martí, Rodriguez & Reipurth (1993)

  6. Polarization in the jets Carrasco-González, Rodríguez et al. 2010 B = 0.2 mG,

  7. Interactionwiththe ISM Thewholesource (protostar + jets) isembedded in the molecular cloud Araudo, Romero, Bosch-Ramon & Paredes 2007, A&A 476, 1289

  8. SED for HH 80-81 a=100 Bosch Ramon et al. (2010), ncloud = 103/cm3.

  9. Themassiveprotostar IRAS 16547-4247 Southernlobe: S=ctena, a~ -0.6 d=2.9 kpc B~10-3 G Vs~1000 km/s Clear non-thermal emission Rodríguez et al. (2005) VLA

  10. SEDs of non-thermal region at the end of the jet Araudo, Romero, Bosch-Ramon & Paredes 2007, A&A 476, 1289

  11. Case dominatedbyprotons Araudo et al. (2007)

  12. Westerlund 2/ RCW 49 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red)

  13. Westerlund 2/ RCW 49 Aharonian, F.A., et al., 2006

  14. HESS Collaboration

  15. Westerlund 2/ RCW 49 PSR J1022-5746

  16. Westerlund 2/ RCW 49 HESS Coll. Expectedsize of the PWN Size of HESS J1023-575 K&C 1984 Additionalcontributions?

  17. RCW 49 / Westerlund 2 Benaglia et al. 2012

  18. Stellarbow shocks • Arc-shapedfeatures of piled-up material • Samedirection as stellarvelocity • WindsconfinedbyISM rampressure • Distancetostarbymomentum balance • Radiationfromshocked gas heats • sweptdust • Dust re-radiates as MIR and FIR excess

  19. E-BOSS v.1 28 cands(out of 283 OB runawaystarsknown) Peri, Benaglia, et al. 2012, A&A

  20. Modelingbow-schocks and theiremission Relativisticparticles are accelerated at the reverse adiabatic shock in thestellarwind

  21. Modelingbow-schocks and theiremission

  22. Most of theprotons escape These p can powerthe extended source del Valle & Romero In prep.

  23. Spectralenergydistributionsfor O4I and O9I stars del Valle & Romero 2012, A&A

  24. Another case: Westerlund 1 HESS Coll.

  25. Another case: Westerlund 1 Seealso poster by Martí et al. onMonoceros

  26. AE AuriageLópez-Santiago, Miceli, del Valle, Romero, et al. ApJ Lett2012 Absorbed X-raypowerlaw ~ -2.5

  27. AE AuriageLópez-Santiago, Miceli, del Valle, Romero, et al. ApJLett 2012 WISE + 1-8 keV EPIC mapEnergymap

  28. VLA + MSX images of BD+43o3654 Benaglia, Romero, et al 2010, A&A C band L band

  29. SED Benaglia, Romero, et al 2010, A&A

  30. zOphbow-shock del Valle & Romero 2012, A&A SED and sensitivities ComputedBS & WISE image

  31. Is HD 195592 a Fermi source?del Valle, Romero, & De Becker 2012

  32. Conclusions • * Protostars in SFRs can be gamma-raysourceswhenembedded in the original molecular core. • * Thetypicalluminosities are ~ 1031-33 erg/s at E>100 MeV. • * Runawaymassivestars can produce relativisticparticles in theirbowshocks, and local (IC) and difusse (pp) gamma-rayemission. • * Somenearbyrunaway O stars can bedetected in gamma-raysby Fermi and in thefutureby CTA. • Gamma-rayastronomy can open a new windowtothestudy of massivestarformingprocesses.

  33. What a world! “Relaxed gamma-rayastronomyteam” Thanks!

  34. Gamma rays from massive stars: not a new idea

  35. Some basic parameters for HH 80-81 • vj ~ 700 km/s • n ~1000 cm-3 • RHH ~ 5 1016 cm • D ~ 1.7 kpc • LX ~ 4 1031 erg/s • Beq ~ 5 mG • E max, p ~ 3 1014 eV - E max, e ~ E max, p/12 See Martí et al. (1993) and Pravdo et al. (2004) for details on the source

  36. HH 80-81: the central source Martí, Rodriguez & Reipurth (1993)

  37. Distributions # Number of stars vs. Spatialvelocity Tetzlaff + 2010 10 20 30 50 70 90 130 Km/s Peri, Benaglia, et al. 2012, A&A

  38. Distributions detected BS Peri, Benaglia, et al. 2012, A&A GC

  39. Benaglia et al. 2012

  40. Absorption

  41. Energy losses and gains tpp ~2 1012 s >> tesc ~ 3 109 s tBremsstr ~3 1013 s tacc ~ η E/qBc, where η =(8/3)(vs/c)2 tesc = tacc  3 1014 eV (for protons)

  42. Thestar BD+43o3654 IRAS bow shock candidates (Noriega-C. et al. 1997) Comerón & Pasquali 2007: Bow shock at MSX-D, E bands RunawayfromCyg OB2, 1.4 kpc O4 If ; 70 Mo ; 1.6 Myr; [vw = 3200 km/s] Kobulnickyet al. 2010: v~ 80km/s, dM/dt ~ 2 x 10-4 Mo/yr Ambientdensity: 6 to 100 cm-3 A non-thermalemitter?

  43. MSX emission toward BD+430 3654 D-band image (14.65 mm)

  44. VLA obs L-band Benaglia, Romero, et al 2010, A&A C-band

  45. Images Is all emnission coming from the BOW SHOCK? Benaglia, Romero, et al 2010, A&A 5’ ~ 2pc

  46. Spectralindexmap a • S(n) ~ kna • s/n (cont) ≥ 4 • s/n (a) ≥ 10 • -0.8 ≤ a ≤ 0.3. • <a> -0.4 Benaglia, Romero, et al 2010, A&A noise

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