Closing in on the NIRB & γ-ray Opacities

Transcription

1 Closing in on the NIRB & γ-ray Opacities NIRB Garching 2015 Sean T. Scully James Madison University Mathew A. Malkan UCLA Floyd W. Stecker NASA/GSFC

2 The intensity of the intergalactic background light (IBL) is substantially constrained from the observational data available from the UV through the FIR (inclusive of the NIRB)

3 The intensity of the intergalactic background light (IBL) is substantially constrained from the observational data available from the UV through the FIR (inclusive of the NIRB) The density of the low energy photons is connected to γ-rays through their mutual annihilation via e + e - pair production in intergalactic space (Stecker de Jager & Salamon 1992): TeV GAMMA RAYS FROM 3C 279: A POSSIBLE PROBE OF ORIGIN AND INTERGALACTIC INFRARED RADIATION FIELDS

4 From the cross section, the peak pair-production by a photon of wavelength λ in microns for energy E in TeV is given by λ µm = 1.33E TeV

5 We present the results of a fully empirical approach to calculating the IBL and γ-ray opacity of the universe obtained from observational data in many wavebands from local to deep galaxy surveys up through and including the NIRB Scully, Malkan & Stecker 2014, An Empirical Determination of the Intergalactic Background Light Using NIR Deep Galaxy Survey Data out to 5 μm and the Gamma-ray Opacity of the Universe ApJ 784,138 Stecker, Malkan, & Scully 2012, A Determination of the Intergalactic Redshift Dependent UV-Optical-NIR Photon Density Using Deep Galaxy Survey Data and the Gamma-ray Opacity of the Universe ApJ 761,128

6 IR, optical, and UV photons are produced from stars and dust re-radiation of starlight in galaxies escaping to intergalactic space If we know enough about galaxy evolution and dust we could calculate the intergalactic photon densities from these processes

7 Approaches range from semi-analytic models (e.g. Gilmore et al. 2009, Somerville et al. 2011) to those that make assumptions about how luminosity functions evolve (e.g. Malkan & Stecker 1998, Kneiske et al. 2002, Stecker et al. 2006, Franceschini et al. 2008, Finke et al. 2010, Kneiske & Dole 2010 )

8 Empirical models attempt to fully constrain the IBL through observational data alone (e.g. Domínguez et al. (2011), Helgason & Kashlinsky 2012, Stecker et al. 2012, Scully et al. 2014) An empirical approach allows us to quantify the uncertainties in the IBL in a model-independent way and calculate the resulting γ-ray opacities and their uncertainties.

9 Determination of the Intergalactic z-dependent UVoptical-NIR photon density The co-moving radiation density u ν (z) is derived from the co-moving specific emissivity ε ν (z) in turn derived from the galaxy luminosity function Φ(L) (i.e. galaxies of luminosity L ν in Mpc -3 dex -1 ), which comes from the survey data L max ε ν (z) = dl ν Φ(L ν ;z) L min NOTE: In our approach, we restrict ourselves to those references that calculate the luminosity densities directly

10 The co-moving radiation density u ν (z) is the time integral of the co-moving specific emissivity ε ν (z) u ν (z) = z max z dz 'ε ν ' (z ') dt dz (z ')e τ eff (ν,z,z ') where ν =ν(1+z )/(1+z) and z max is the redshift corresponding to initial galaxy formation (Salamon & Stecker 1998) and dt (z) = H (1+ z) Ω dz + Ω 0 Λ m (1+ z)3 1

11 z FUV NUV U B V R I.05 SC05, WY05 WY05.1 BU05,CU12 BU05,CU12.15 TR07 TR07 TR07 TR07 TR07 TR07 TR07.20 BU05 BU05.25 WO03 WO03 WO03.3 SC05,CU12,SC05,TR07 TR07,CU12 TR07,DA05 TR07,DA05,FA07 TR07 TR07 TR07.35 DA07, WO03 WO03 WO03.45 WO03 DA05 DA05, WO03 WO03.5 SC05, CU12, TR07 TR07 TR07 TR07, FA07 TR07 TR07 TR07.55 DA07, WO03 WO03 WO03.6 DA05 DA05 CH03.65 WO03 WO03 MA12 WO03.7 TR07,CU12 TR07 TR07, FA07 TR07 TR07 TR07.75 WO03 WO03 WO03.85 WO03 WO03 WO03.9 TR07,CU12 TR07,CU12 TR07, DA05 TR07, DA05, FA07 TR07 TR07 TR07.95 WO03 DA05 WO03, DA05 MA12 WO03, DA SC05 WO03 WO03 WO CU12, TR07, DA07, BU07 DA07,TR07,CU12, WO03 TR07 TR07, FA07, WO03 TR07 TR07, WO03 TR DA05 DA05 CH03, DA CU12, TR07 TR07 TR07 TR07 TR07 TR07 TR CU12 CU DA05 DA05 DA TR07 TR07 TR07 TR07 TR07 TR07 TR DA05 DA05 DA DA07 DA07 MA DA05 DA05 DA SC CU12 CU RE08, SA06 MA07 MA07 MA LY MA SC CU12 CU12 MA07 MA07, MA PA BO07 MA YO06,CU SA IW BO BO BO OE BO10 Bouwens et al. (2007)(BO07) Bouwens et al. (2010)(BO10) Budavári et al. (2005)(BU05) Burgarella et al. (2007)(BU07) Chen et al. (2003)(CH03) Cucciati et al. (2012)(CU12) Dahlen et al. (2007)(DA07) Faber et al. (2007)(FA07) and references therein Iwata et al. (2007)(IW07) Ly et al. (2009)(LY09) Reddy & Steidel (2009)(RE09) Marchesini et al. (2007)(MA07) Marchesini & Van Dokkum 2007 (MAV07) Marchesini et al. (2012)(MA12) Oesch et al. (2010)(OE10) Paltani et al. (2007)(PA07) Reddy et al. (2008)(RE08) Sawicki & Thompson (2006)(SA06) Schiminovich et al. (2005)(SC05) Steidel et al. (1999)(ST99) Tresse et al. (2007) (TR07) Wolf et al. (2003) (WO03) Wyder et al. (2005)(WY05) Yoshida et al. (2006)(YO06)

12 β Log (1+z) A key feature of our work is that we used colors between the wavebands to fill in the gaps and jumps where the data is lacking.

13 Relationship β(fuv NUV)= log(1+z), log(1+z) 0.8 β(b V)= log(1+z), log(1+z) 0.6 β(nuv U)= log(1+z), log(1+z) 0.6 β(nuv R)= log(1+z), log(1+z) 0.6 β(u V)= log(1+z), log(1+z) 0.6 β(u B)= log(1+z), log(1+z) 0.6 References Bouwens, et al. (2009); Budavári et al.(2005); Castellano et al. (2012); Cucciati, et al. (2012); Dunlop et al. (2012); Willott, et al. (2012); Wyder et al.(2005) Arnouts et al.(2007); Brammer (2011) Tresse et al. (2007) Arnouts, et al. (2007); Brammer (2011): Ly et al. (2009) Arnouts, et al. (2007); Brammer (2011): Ly et al. (2009) Marchesini et al. (2007); Gonźalez et al. (2011)

14 The continuum emission from galaxies between 0.8 μm and 5 μm arises predominantly from stellar photospheres and in near infrared (NIR) wavelengths, the light is mostly emitted by red giant stars. We used the SEDs from Dai et al. (2009) for 3.6, 4.5, 5.8, and 8.0 μm utilizing combined photometry from the Spitzer/IRAC Shallow Survey for redshifts < 0.5. At higher redshifts, we have used template SEDs derived by Kriek et al. (2010,2011), which utilized extensive multi-band photometry obtained for a sample of 3500 K-band selected galaxies, at redshifts between z = 0.5 and z = 2.0

15 Log Ν Watts Hz 1 Mpc Far UV Log Ν Watts Hz 1 Mpc Near UV Log Ν Watts Hz 1 Mpc 3 Log Ν Watts Hz 1 Mpc 3 Log Ν Watts Hz 1 Mpc Log 1z Log 1z U Band Log 1z V Band 17.5 Log 1z I Band Log Ν Watts Hz 1 Mpc 3 Log Ν Watts Hz 1 Mpc 3 log ΡL Watts Hz 1 Mpc Log 1z Log 1z B Band Log 1z R Band 17 Log 1z

16 log ΡL Watts Hz 1 Mpc 3 log ΡL Watts Hz 1 Mpc Bell et al Feulner et al HeathJones et al Hill et al Pozzetti et al 2003 Stefanon & Marchesini Arnouts et al Bell et al Feulner et al HeathJones et al Hill et al Kochanek et al Pozzetti et al 2003 Stefanon & Marchesini 2013 Log 1z J Band 17.5 Log 1z L Band log ΡL Watts Hz 1 Mpc 3 log ΡL Watts Hz 1 Mpc Arnouts et al Bell et al Feulner et al HeathJones et al Hill et al Kochanek et al Pozzetti et al Arnouts et al Bell et al Feulner et al HeathJones et al Hill et al Kochanek et al Pozzetti et al 2003 Stefanon & Marchesini 2013 Log 1z K Band 17.5 Log 1z M Band

17 The Redshift-Dependent Υ-Ray Opacity Calculation τ (E γ,z) = z source dz dl dx x dz m 2 e c 4 E γ x (1+z ) d ε n(ε,z)σ (s) E γ = E γ (z = 0) x = 1 cosθ θ γ γ s = 2xE γ ε(1+ x) e e + σ (s) = σ 0 (1 β 2 ) 2β(β 2 2) + (3 β 4 )ln 1+ β 1 β 1/2 dl = c (1+ z) 1 Ω + Ω (1+ z) 3 dz H Λ m 0 1/2

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19 1.6 TeV 1+ z

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21 Log Energy GeV Redshift A τ = 1 energy-redshift plot (Fazio & Stecker 1970) showing our uncertainty band results compared with the Fermi plot of their highest energy photons from FSRQs (red), BL Lacs (black) and GRBs (blue) vs. redshift (from Abdo et al. 2010)

22 Log Τ Log ε ev Determination of the upper limit redshift for BL Lac PKS The points represent the upper limits to the γ-ray opacity derived from the VERITAS data. The dashed curve corresponds to our lower limit opacity for z =.6035 while the solid curve is our best fit lower limit opacity to the opacity limits derived from our opacities corresponding to an upper limit redshift of z = 1.0.

23 We are working to extend our calculation through the mid-ir and far-ir. Observational constraints on low energy photons can be combined with new constraints from Fermi & ground-based TeV observatories to zero in on the NIRB and γ-ray opacities. Many BL Lacs in the Fermi catalogue lack spectroscopic redshift determinations. A comparison to those that are determined can further constrain the allowed range of opacities. The physics of γ-ray and neutrino production from pion decay, together with the pion production by interactions of relativistic nucleons with both photons and nucleons in astrophysical settings can be used to explore the production of neutrinos in galaxies, AGN, GRBs and connect an unresolved extragalactic background to the IceCube data (Aartsen 2014)