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Galaxies at Radio Wavelengths
Published in Ronald L. Snell, Stanley E. Kurtz, Jonathan M. Marr, Fundamentals of Radio Astronomy, 2019
Ronald L. Snell, Stanley E. Kurtz, Jonathan M. Marr
We can learn more about these galaxies from their spectral line emission. Unfortunately, our current technology does not have the sensitivity to detect the 21-cm HI emission line in these very distant galaxies. The largest redshift for which the 21-cm line of HI has been detected is only 0.3. Future radio telescope arrays, such as the Square Kilometer Array (SKA), Square Kilometer Array (SKA) will have much larger collecting areas and the sensitivity at longer wavelengths to detect the HI line in more distant galaxies. Submillimeter galaxies!CO Fortunately, the rotational lines of CO have much larger fluxes and so are more readily detectable in these submillimeter galaxies. These CO observations have revealed that these galaxies are rich in molecular gas. Detection of the CO spectral lines also is a means of determining the redshift. In fact, for submillimeter galaxies not detected at optical wavelengths, this is the only means of determining a spectroscopic redshift. An example of detection of CO spectral lines in a submillimeter galaxy is shown in Figure 8.17 for the galaxy PJ160917.8. PJ160917.8Submillimeter galaxies!PJ160917.8 This spectrum shows two spectral lines due to two different rotational transitions of CO and provides a unique determination of the galaxy's redshift of 3.26.
Detectors
Published in C. R. Kitchin, Astrophysical Techniques, 2020
The SKA is currently under development with a number of preliminary studies and projects already completed. The main sites for the $2 billion instrument have been chosen as the Murchison Radio Astronomy Observatory in Western Australia and the Karoo desert in South Africa’s Northern Cape Province. Additionally, there will also be outlier stations in a number of other Southern Hemisphere sites. The SKA is scheduled for completion104 around 2030 and will be a phased array of many small receivers whose total collecting area will be 1 km2 (106 m2). It will cover the spectral region from 70 MHz to 30 GHz and have a maximum baseline of 3,000 km.
New frontiers in computing and data analysis – the European perspectives
Published in Radiation Effects and Defects in Solids, 2019
Among the numerous research projects and programs from the ‘Big Data Universe’ in which the European Astrophysics community is involved, the most challenging projects are as follows: CTA – Cherenkov Telescope Array (1): With more than 100 telescopes distributed between the northern and southern hemisphere of the planet, CTA will be the largest and most sensitive high-energy gamma-ray observatory ever built in the world. CTA studies will include, among others, the most energetic phenomena in the universe. This is a really Big Data project capable of generating large data volumes of more than 4 PBytes per year, widely expected to exceed 100 PBytes by 2030.SKA – Square Kilometer Array and precursors: The Square Kilometer Array (SKA) (2) project is an international effort to build the world’s largest radio telescope, with over a square kilometer of collecting area. The SKA will use thousands of dishes and up to a million low-frequency antennas that will enable astronomers to monitor the sky in unprecedented detail. SKA in full operation will produce 750 PB per year for the first 10 years of operation and over 8.5 ExaBytes for 15 years.