The wave–particle duality of electrons was demonstrated in a kind of two-slit interference experiment using an electron microscope equipped with an electron biprism and a position-sensitive electron-counting system. Such an experiment has been regarded as a pure thought experiment that can never be realized. This article reports an experiment that successfully recorded the actual buildup process of the interference pattern with a series of incoming single electrons in the form of a movie.

We analyzed the ASCA X-ray data of 40 nearby clusters of galaxies, whose intraclustermedium temperature distributes in the range of 0.9-10 keV. We measured the Si and Fe abundances of the intracluster medium, spatially averaging over each cluster, but excluding the central ∼ 0.15h −1 50 Mpc region in order to avoid any possible abundance gradients and complex temperature structures. The Fe abundances of these clusters are 0.2-0.3 solar, with only weak dependence on the temperature of the intracluster medium, hence on the cluster richness. In contrast, the Si abundance is observed to increase from 0.3 to 0.6-0.7 solar from the poorer to richer clusters. These results suggest that the supernovae of both type-Ia and type-II significantly contribute to the metal enrichment of the intracluster medium, with the relative contribution of type-II supernovae increasing towards richer clusters. We suggest a possibility that a considerable fraction of type-II supernova products escaped from poorer systems.

We present a 0.72 deg2 contiguous 1.1‐mm survey in the central area of the Cosmological Evolution Survey field carried out to a 1σ≈ 1.26 mJy beam−1 depth with the AzTEC camera mounted on the 10‐m Atacama Submillimeter Telescope Experiment. We have uncovered 189 candidate sources at a signal‐to‐noise ratio (S/N) ≥ 3.5, out of which 129, with S/N ≥ 4, can be considered to have little chance of being spurious (≲2 per cent). We present the number counts derived with this survey, which show a significant excess of sources when compared to the number counts derived from the ∼0.5 deg2 area sampled at similar depths in the Submillimetre Common‐User Bolometer Array (SCUBA) HAlf Degree Extragalactic Survey (SHADES). They are, however, consistent with those derived from fields that were considered too small to characterize the overall blank‐field population. We identify differences to be more significant in the S1.1mm≳ 5 mJy regime, and demonstrate that these excesses in number counts are related to the areas where galaxies at redshifts z≲ 1.1 are more densely clustered. The positions of optical–infrared galaxies in the redshift interval 0.6 ≲z≲ 0.75 are the ones that show the strongest correlation with the positions of the 1.1‐mm bright population (S1.1mm≳ 5 mJy), a result which does not depend exclusively on the presence of rich clusters within the survey sampled area. The most likely explanation for the observed excess in number counts at 1.1‐mm is galaxy–galaxy and galaxy–group lensing at moderate amplification levels, which increases in amplitude as one samples larger and larger flux densities. This effect should also be detectable in other high‐redshift populations.

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We report the results of the counterpart identification and a detailed analysis of the physical properties of the 48 sources discovered in our deep 1.1‐mm wavelength imaging survey of the Great Observatories Origins Deep Survey‐South (GOODS‐S) field using the AzTEC instrument on the Atacama Submillimeter Telescope Experiment. One or more robust or tentative counterpart candidate is found for 27 and 14 AzTEC sources, respectively, by employing deep radio continuum, Spitzer/Multiband Imaging Photometer for Spitzer and Infrared Array Camera, and Large APEX Bolometer Camera 870 μm data. Five of the sources (10 per cent) have two robust counterparts each, supporting the idea that these galaxies are strongly clustered and/or heavily confused. Photometric redshifts and star formation rates (SFRs) are derived by analysing ultraviolet(UV)‐to‐optical and infrared(IR)‐to‐radio spectral energy distributions (SEDs). The median redshift of zmed∼ 2.6 is similar to other earlier estimates, but we show that 80 per cent of the AzTEC–GOODS sources are at z≥ 2, with a significant high‐redshift tail (20 per cent at z≥ 3.3). Rest‐frame UV and optical properties of AzTEC sources are extremely diverse, spanning 10 mag in the i‐ and K‐band photometry (a factor of 104 in flux density) with median values of i= 25.3 and K= 22.6 and a broad range of red colour (i−K= 0–6) with an average value of i−K≈ 3. These AzTEC sources are some of the most luminous galaxies in the rest‐frame optical bands at z≥ 2, with inferred stellar masses M*= (1–30) × 1010 M⊙ and UV‐derived SFRs of SFRUV≳ 101‐3 M⊙ yr−1. The IR‐derived SFR, 200–2000 M⊙ yr−1, is independent of z or M*. The resulting specific star formation rates, SSFR ≈ 1–100 Gyr−1, are 10–100 times higher than similar mass galaxies at z= 0, and they extend the previously observed rapid rise in the SSFR with redshift to z= 2–5. These galaxies have a SFR high enough to have built up their entire stellar mass within their Hubble time. We find only marginal evidence for an active galactic nucleus (AGN) contribution to the near‐IR and mid‐IR SEDs, even among the X‐ray detected sources, and the derived M* and SFR show little dependence on the presence of an X‐ray bright AGN.