The coldest place in the Universe?

This remarkable image of the Boomerang Nebula shows an hour-shaped outflow of gas and dust coming from a dying red giant star. ALMA observations that were processed using CASA have revealed the presence of an ultra-cold gas outflow, induced when a companion star plunged into the red giant. This outflow is expanding and cooling so rapidly that its temperature has fallen below the temperature of the micro-wave background. The red hour-shaped feature is CO(3-2) emission that has been swept up by a jet from the inner regions of the ultra-cold outflow. The blue haze represents scattered light imagesd with HST.

Credit: ALMA (ESO/NAOJ/NRAO); NASA/ESA Hubble; NRAO/AUI/NSF

ALMA Media release

Publication: R. Sahai, W. H. T. Vlemmings, and L-A. Nyman: "The Coldest PLace in the Universe: Probing the Ultra-cold Outflow and Dusty Disk in the Boomerang Nebula", 2017, ApJ, 841, 110




ALMA images the Sun

A new image taken with ALMA and reduced with CASA reveals stunning details of our Sun, including an evolving sunspot that is nearly twice the diameter of the Earth. This image was taken as part of ALMA's solar commissioning campaign. It captures the millimeter-wavelength light emitted by the Sun's chromosphere - the region that lies just above the photosphere, the visible surface of the Sun. The Sun is much brighter and larger than the distant objects that ALMA typically observes. Therefore, the solar commissioning team not only had to develop special procedures to enable ALMA to safely image the Sun, but also faced challenges in terms of data reduction in CASA. More details of this can be read in our recent CASA Newsletter.

Credit: ALMA (ESO/NAOJ/NRAO)

NRAO Media Release

Publication: M. Shimojo, T. Bastian, A. Hales, et al., "Observing the Sun with the Atacama Large Millimeter/submillimeter Array (ALMA): High-Resolution Interferometric Imaging", Solar Physics, 292, 87.




From NVSS to VLASS

The Karl G. Jansky Very Large Array has embarked on new survey of the sky, the VLA Sky Survey (VLASS). VLASS wil make three complete scans of 80 percent of the entire sky at 2-4 GHz over the course of the next 7 years. VLASS is the third major survey of the VLA, following the NRAO VLA Sky Survey (NVSS) and Faint Images of the Radio Sky (FIRST). The image on the left visualizes the increase in resolution of VLASS compared to NVSS and FIRST. Shown is an overlay of the same pair of radio sources observed with NVSS (orange background "blob"), FIRST (yellow/orange emission in the center) and VLASS (red/white image in the center). The resolution increases from 45 arcsec in NVSS to 5 arcsec in FIRST to 2.5 arcsec in VLASS. The vast amounts of data that will be collected for VLASS will be reduced and imaged with CASA trhough a dedicated software pipeline. Astronomers expect the VLASS to discover powerful cosmic explosions, dust-enshrouded stars and galaxies, cosmic magnetic fields, and powerful jets of relativistic particles eminating from supermassive black holes..

Credit: Bill Saxton, NRAO/AUI/NSF (adapted from its original version)

NRAO Media Release




Sphere of debris around the giant star U Antliae

The ageing giant star 'U Antliae' lies roughly 900 light-year from Earth. Using the Atacama Large Millimeter/submillimeter Array (ALMA), a team of astronomers has imaged a huge sphere of debris around this giant star. This is not an extraterrestrial civilization that blow up its star system... What happened is that around 2,700 years ago, U Antliae went through a short period of rapid mass loss, ejecting cold gas out into space at high speeds. The image shows a shell of carbon-monoxide, or CO. Outbursts like these can enrich star systems with chemical compounds like carbon and oher elements. The team used relied on the CASA pipeline for calibrating the data, and used CASA's flexibility for customizing the final imaging as well as adding single-dish data to recover the overall structure of the debris shell.

Credit: ALMA (ESO/NAOJ/NRAO)/F. Kerschbaum

ALMA Media Release

Publication: F. Kerschbaum, M. Maerker, M. Brunner, et al., "Rings and filaments: The remarkable detached CO shell of U Antliae", A&A, 605, 116.




Einstein-ring of distant lensed galaxy

This image shows a galaxy that is 12 billion light-years away, seen at a time when the Universe was only 15 percent of its current age. Its ring-shape appearance is the result of its light being bent by a massive foreground galaxy (not visible in this image), which acts like a cosmic lens. The result is a so-called Einstein ring, revealed by glowing dust and molecular gas within the galaxy. This image is the highest resolution image made to date with the Atacama Large Millimeter/submillimeter Array (ALMA). The CASA software was required for reducing and imaging these challanging ALMA data.

Credit: ALMA (NRAO/ESO/NAOJ); B. Saxton, NRAO/AUI/NSF

NRAO Media Release

Publication: ALMA Partnership, C. Vlahakis, T. Hunter, et al., "ALMA Long Baseline Observations of the Strongly Lensed Submillimeter Galaxy HATLAS J090311.6+003906 at z=3.042", ApJL, 808, 4.




ALMA and VLA zoom in on planet Formation

ALMA, VLA and CASA have teamed up to provide this stunning image of HL Tau, a system that astronomers think may reflect the very earliest stages in the formation of planets. The Atacama Large Millimeter/submillimeter Array (ALMA) observed this intriguing system in 2014, while testing ALMA for operating at its highest resolution. Subsequent observations with the Karl G. Jansky Very Large Array (VLA), as shown by the central yellow feature, were needed to image clumps of dust in the very central region out of which planets similar to our Earth may form.

Credit: Carrasco-Gonzalez, et al.; Bill Saxton, NRAO/AUI/NSF

NRAO Media Release

Publications: Carrasco-Gonzalez, C. Henning, C. Chandler, et al. "For the survey, the VLA will receive cosmic radio emissions at frequencies between 2 and 4 GigaHertz,", ApJL, 821, 16

ALMA Partnership, C. Brogan, L. Perez, et al. "The 2014 ALMA Long Baseline Campaign: First Results from High Angular Resolution Observations toward the HL Tau Region", ApJL, 808, 3.




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