ALMA-IMF

ALMA Chapter 3.1: Calibration issues for ALMA

The precision imaging to be attained by the ALMA will be achieved through accurate calibration. The types of calibration are summarized in Table 3.1. Table 3.1 ALMA Calibration Requirements. Pointing 0.6" absolute Primary Beam 2-3% Baseline Determination 0.1 mm Flux Calibration 1% absolute flux accuracy goal Phase Calibration 0.15 radian at 230 GHz Bandpass Calibration 10000:1 to 100000:1 Polar...

ALMA Memo XXX Bandpass Calibration for ALMA

This memo contains a detailed evaluation of the expected performance of the bandpass calibration for ALMA. We evaluate the limitations on the bandpass accuracy due to the imperfect knowledge of the atmospheric transmission. We show that the best bandpass accuracy is obtained when the amplitude calibration is applied in a single-load scheme. The proposed scheme is a variant of the so-called band...

ALMA Memo 493 Finding Fast Switching Calibrators for ALMA

In order to perform fast switching phase calibration effectively, we need to have a database of bright point-like sources at millimeter wavelengths. Optimally, this would include flux measurements at 86 GHz and spectral information at higher frequencies. We present a sample of 31145 compact flat spectrum radio sources with −40 < δ < +60, presumed extragalactic, which will be likely candidates f...

ALMA Memo No. 324 Proposal for ALMA Front End Optics

ALMA Memo #303 Water Vapour Radiometers for ALMA

The JCMT-CSO single-baseline interferometer was the first to demonstrate phase correction using the 183 GHz line, using equipment built by Martina Wiedner, Richard Hills and colleagues. Only a limited quantity of data were gathered but the results (ALMA memo 252) were encouraging and suggested that even an uncooled system could provide effective phase calibration at submillimetre wavelengths. S...