Constraints on the Cosmic Near-Infrared Background Excess from NICMOS Deep Field Observations


Thompson RI, Eisenstein D, Fan X, Rieke M, Kennicutt RC. Constraints on the Cosmic Near-Infrared Background Excess from NICMOS Deep Field Observations. The Astrophysical Journal. 2007;657 :669-680.

Date Published:

March 1, 2007


NICMOS observations of the resolved object fluxes in the Hubble DeepField-North and the Hubble Ultra Deep Field are significantly below thefluxes attributed to a 1.4-1.8 μm near-infrared background excess(NIRBE) from previous low spatial resolution NIRS measurements. Testsplacing sources in the NICMOS image with fluxes sufficient to accountfor the NIRBE indicate that the NIRBE flux must be either flat on scalesgreater than 100" or clumped on scales of several arcminutes to avoiddetection in the NICMOS image. A fluctuation analysis of the new NICMOSdata shows a fluctuation spectrum consistent with that found at the samewavelength in deep 2MASS calibration images. The fluctuation analysisshows that the majority of the fluctuation power comes from resolvedgalaxies at redshifts of 1.5 and less and that the fluctuations observedin the earlier deep 2MASS observations can be completely accounted forwith normal low-redshift galaxies. Neither the NICMOS direct fluxmeasurements nor the fluctuation analysis require an additionalcomponent of near-infrared flux other than the flux from normal resolvedgalaxies in the redshift range between 0 and 7. The residualfluctuations in the angular range between 1" and 10" is 1-2 nWm-2 sr-1, which is at or above several predictionsof fluctuations from high redshift Population III objects, butinconsistent with attributing the entire NIRBE to high-redshiftgalaxies.