New Cosmological Structures on Medium Angular Scales Detected with the Tenerife Experiments

Abstract

We present observations at 10 and 15 GHz taken with the Tenerife experiments in a band of the sky at declination +35°. These experiments are sensitive to multipoles in the range l = 10-30. The sensitivities per beam are 56 and 20 μK for the 10 and 15 GHz data, respectively. After subtraction of the prediction of known radio sources, the analysis of the data at 15 GHz at high Galactic latitude shows the presence of a signal with amplitude ΔTrms ∼ 32 μK. In the case of a Harrison-Zeldovich spectrum for the primordial fluctuations, a likelihood analysis shows that this signal corresponds to a quadrupole amplitude Qrms-Ps - 20.1-5.4 +7.1in agreement with our previous results at declination +40° and with the results of the COBE DMR. There is clear evidence for the presence of individual features in the right ascension range 190°-250° with a peak-to-peak amplitude of ∼110 μK. A preliminary comparison between our results and COBE DMR predictions for the Tenerife experiments clearly indicates the presence of individual features common to both. The constancy in amplitude over such a large range in frequency (10-90 GHz) is strongly indicative of an intrinsic cosmological origin for these structures. © 1997. The American Astronomical Society. All rights reserved.