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MeerKLASS team presents deepest ever single-dish neutral hydrogen intensity maps
from Contact 17
BY DR HILARY KAY (THE UNIVERSITY OF MANCHESTER)
The international MeerKAT Large Area Synoptic Survey (MeerKLASS, PI Mario Santos) collaboration has released the deepest-ever single-dish neutral hydrogen intensity maps, created from 64 hours of data and covering over 200 square degrees of sky. The work has been published in the Monthly Notices of the Royal Astronomical Society.
Neutral hydrogen gas is an important tracer of largescale cosmic structure and is rich in information that can help us understand our Universe. However, the emission is faint and hard to detect. By pioneering a single-dish observing mode using the MeerKAT dishes as individual scanning telescopes rather than an interferometer, the team has been able to employ the technique of intensity mapping (where combined, unresolved emission is measured rather than detecting the individual galaxies and charting their positions) to vast areas of sky.
Exploiting the improved signal-to-noise detection provided by the observations enabled the team to develop a more sophisticated calibration and analysis pipeline. Validating this pipeline using both a suite of mock simulations as well as data from the Galaxy and Mass Assembly (GAMA) survey, the team was able to obtain a statistically significant detection of radio emission associated with the positions of the GAMA galaxies.
“The new signal detection is a great validation of the results from our first pilot survey and demonstrates the fantastic progress on our techniques and pipelines advanced by the team of brilliant scientists behind this result,” said Dr Laura Wolz, Deputy-PI of the study.
The MeerKLASS collaboration has recently had its extra-large proposal at MeerKAT accepted, which will see the collaboration conduct a further 500 hours of single-dish observations at lower frequencies, increasing the cosmic volume in the maps by two orders of magnitude.
