Isotropy of Hubble Diagrams by Bastian Weinhorst Bielefeld, in collaboration with Dominik J. Schwarz

Motivation The cosmological principle states that the universe is homogeneous and isotropic on large scales – it is important to test this fundamental principle in every thinkable way The Hubble law is a direct consequence of the cosmological principle The need for Dark Energy and equivalently the value of q 0 relies on high-z and low-z SN data, mostly the latter will be tested upon anisotropies Large scale pertubations give rise to anisotropies in the Hubble diagram There are anomalies on the largest angular scales in the CMB Are there similiar anomalies in SN Ia data? (Copi, Huterer, Schwarz, Starkmann: astro-ph/ ) (Bonvin, Durrer, Gasparini: astro-ph/ ) Strategy: model independent tests (no Friedmann equations)

bin redshift Hubble Diagram The Hubble law to first order: Delta redshift z Data taken from: (Tonry et al.: astro-ph/ ) z in CMB frame (Barris et al.: astro-ph/ )

Analysing-Tools Normally one can fit H 0 by finding the minimum of the following  ² Additionally we added a dipole-term Minimizing gives a set of parameters for monopole and dipole in each bin

0.025<z h < <z h < <z h < <z h < Sn Ia Dipole = WMAP Dipole?  ² min /DOF=1.39  ² min /DOF=0.46  ² min /DOF=1.52  ² min /DOF=1.07 (Hinshaw et al.: astro-ph/ ) Contours ~ C.L. for dipol-directionColor ~ dipol-amplitude <z h <0.025 (heliocentric)

Color ~ dipole-amplitude Dipole-Fits in CMB rest frame 0.1<z< <z<2.0 Pointsize ~ |  |, Color ~ ,  ² min /DOF =1.22 Pointsize ~ |  |, Color ~ ,  ² min /DOF =0.68  ² min /DOF =0.68  ² min /DOF =1.22 Contours ~ C.L. for dipole-direction Pointsize~|  |, Color ~  0.1<z<0.4 Contours ~ C.L. for dipole-direction

The Hubble law to second order in redshift (for z<0.1): This gives Direction-dependent evidence for acceleration? Minimizing  ² gives values for H 0, q 0 and confidence intervals

Evidence for acceleration? l=90,b= -45,  ² min /DOF=0.91 l=0,b=90,  ² min /DOF=0.97 Sn with redshifts 0.0<z<0.1  ² min /DOF=0.99 l=0,b= -90,  ² min /DOF=0.98 l=270,b=45,  ² min /DOF=0.95 Isotropy of Hubble diagrams   N SENW S deceleration parameter Hubble constant

Conclusions We confirm the direction of the CMB-dipole with Sn Ia data We find additional dipoles for 0.7<z<2.0 and 0.1<z<0.4, which seem to be correlated to the unexpected quadrupole-octopole plane of the CMB We find hemispherical anisotropies in Hubble diagrams below z=0.1, i.e. no evidence for acceleration in the northern hemisphere Plan to repeat hemispherical analysis within  CDM

Thank you for your interest and attention

quadrupole+octopole WMAP3yr fullsky map (Copi, Huterer, Schwarz, Starkmann: astro-ph/ )