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

We present observations at 10 and 15 GHz taken with the Tenerife experiments in a band of the sky at Dec.=+35. These experiments are sensitive to multipoles in the range l = 10− 30. The sensitivity per beam is 56 and 20 μK for the 10 and the 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 ∆TRMS ∼ 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 +7.1 −5.4 μK, in agreement with our previous results at Dec.+=40 and with the results of the COBE DMR. There is clear evidence for the presence of individual features in the RA range 190 to 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. Subject headings: cosmology large scale structure of the universe cosmic microwave background