![]() Their metronomic radio wave pulses serve as precise clocks that help astronomers study gravity in extreme conditions. MeerKAT will also watch for pulsars, dense and rapidly spinning stellar remnants. It should have the sensitivity to map the faint signal to greater distances than before, and the resolution to see the gas moving in and around galaxies. ![]() Stretched to radio frequencies by the expansion of the universe, these photons land in the telescope's main frequency band. Because of a spontaneous transition in the atoms of neutral hydrogen, the gas constantly emits microwaves with a wavelength of 21 centimeters. The combination makes MeerKAT ideal for mapping hydrogen, the fuel of star and galaxy formation. The VLA can opt for sensitivity or resolution, but not both at once-and only after the slow process of moving its 27 dishes into a different configuration. Its dishes are split into a densely packed core, which boosts sensitivity, and widely dispersed arms, which increase resolution. MeerKAT's dishes are smaller than the VLA's, but having more of them puts it in "a sweet spot of sensitivity and resolution," Camilo says. "It's going to be a challenge," Camilo says. In March, the new supercomputer came online, and the team hopes to be fully operational by early next year. ![]() For early science campaigns last year, 16 dishes were correlated. In a technique called interferometry, computers correlate the signals from pairs of dishes to build a much sharper image than a single dish could produce. With MeerKAT's 64 dishes now in place, engineers are learning how to process the data they gather. "In every country, people are having that discussion on what funding is available," Falcke says. Months of delicate negotiations lie ahead. It would add another 133 dishes to MeerKAT, extending it across 150 kilometers, and place 130,000 smaller radio antennas across Australia-but only if member governments agree to fully fund the work. The first phase of the SKA could begin in 2020 at a cost of €798 million. ![]() MeerKAT, which stands for Karoo Array Telescope along with the Afrikaans word for "more," is one of several precursor instruments for the SKA. With little experience, South Africa has "a major fantastic achievement," says Heino Falcke of Radboud University in Nijmegen, the Netherlands. Sensitive across a wide swath of the radio spectrum, MeerKAT can study how hydrogen gas moves into galaxies to fuel star formation. "For certain studies, it will be the best" in the world, says Fernando Camilo, chief scientist of the South African Radio Astronomy Observatory in Cape Town, which operates MeerKAT. But with new hardware designs and a powerful supercomputer to process data, the newcomer could have an edge on its 40-year-old northern cousin. Jansky Very Large Array (VLA) near Socorro, New Mexico. Spread across 8 kilometers, the dishes have a collecting area similar to that of the great workhorse of astrophysics, the Karl G. The last of 64 13.5-meter dishes was installed late last year, and next month South African President Cyril Ramaphosa will officially open the facility. Meanwhile, on the wide-open plains of the Karoo, a semiarid desert northeast of Cape Town, South Africa, part of the telescope is already in place in the shape of the newly completed MeerKAT, the largest and most powerful radio telescope in the Southern Hemisphere. That boost will help the sometimes-troubled project as, over the next year or so, it forms an international treaty organization and negotiates funding to start construction. Today, the Square Kilometre Array (SKA), a continent-spanning radio astronomy project, announced that Spain has come on board as the collaboration's 11th member.
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