Clustering of the Diiuse Infrared Light from the Cobe Dirbe Maps. I. C(0) and Limits on the Near-ir Background

The cosmic infrared background (CIB) and its anisotropy have not yet been measured, but are important signatures of the early evolution and clustering of galaxies. The near IR is particularly interesting because redshift eeects bring the peak luminosity of distant galaxies into the near IR, allowing high redshift objects to dominate the theoretical predictions of the CIB and its uctuations. This paper is devoted to studying the CIB through its correlation properties. We studied the limits on CIB anisotropy in the near IR (1.25, 2.2, and 3.5 m, or J; K; L) bands at a scale of 0.7 using the COBE 1 Diiuse Infrared Background Experiment (DIRBE) data. In single bands we obtain the upper limits on the zero-lag correlation signal respectively. The DIRBE data exhibit a clear color between the various bands with a small dispersion. On the other hand most of the CIB is expected to come from redshifted galaxies and thus should have diierent color properties. We use this observation to develop a `color subtraction' method of linear combinations of maps at two diierent bands. This method is expected to suppress the dominant uctuations from foreground stars and nearby galaxies, while not reducing (or perhaps even amplifying) the extragalactic contribution to C(0). Applying this technique gives signiicantly lower and more isotropic limits. For the J ? K; J ? L, and K ? L combinations these limits are respectively W 2 m ?4 sr ?2 respectively. We also use simple no-evolution models to interpret these numbers in terms of the total CIB levels, postponing a more detailed interpretation to a forthcoming paper. From the single band uctuations we estimate upper limits on the CIB from clustered matter of (I) z;rms q R (ddI dz) 2 dz < 200, 78 , and 26 nWm ?2 sr ?1 in the J; K, and L bands independently of the evolution history or spectral energy distribution. The color-subtracted signals strongly constrain the color evolution of galaxy populations and, if their degree of isotropy 1 The National Aeronautics and Space Administration/Goddard Space Flight Center (NASA/GSFC) is responsible for the design, development, and operation of the COBE. Scientiic guidance is provided by the COBE Science Working Group. GSFC is also responsible for the development of the analysis software and for the production of the mission data sets. 1 is indicative of a cosmological origin, could allow determination of the total diiuse uxes due …