ALMACAL: Surveying the Universe with ALMA Calibrator Observations

The Atacama Large Millimeter/submillimeter Array (ALMA) has accumulated thousands of hours of observing time on calibrator sources, which are typically bright quasars. These calibration scans are usually observed with the same instrumental setup as the science targets and have enormous potential for conducting science. ALMACAL is a survey that is exploiting these data which are accumulating "for free" with every scheduled ALMA observing project. Here, we present a brief survey status update and summarise the science that can be achieved. For instance, if data acquired during multiple visits to many ALMA calibrators are combined, low continuum noise levels can be reached, allowing the detection of faint dusty star-forming galaxies in a number of bands. Also, redshifted CO and other emission and absorption lines are detected in the ALMACAL data. The total on-source integration time for all ALMACAL scans to date amounts to approximately 2500 hours, more than all ALMA Large Programmes to date combined....