From Gemini Observatory: “Gemini Confirms the Most Distant Radio Galaxy” Radio galaxy TGSS J1530+1049


Gemini Observatory
From Gemini Observatory

Top: Two-dimensional GMOS spectrum of the strong emission line observed in the radio galaxy TGSS J1530+1049. The size of the emission region is a bit less than one arcsec. Bottom: One-dimensional profile of the observed emission line. The asymmetry indicates that the line is Lyman-α at redshift of z = 5.72, making TGSS J1530+1049 the most distant radio galaxy known to date.

Using the Gemini North telescope in Hawai`i, an international team of astronomers from Brazil, Italy, the Netherlands, and the UK has discovered the most distant radio galaxy to date, at 12.5 billion light years, when the Universe was just 7% of its current age.

The team used spectroscopic data from the Gemini Multi-Object Spectrograph (GMOS-N) to measure a redshift of z = 5.72 for the radio galaxy identified as TGSS J1530+1049.


This is the largest redshift of any known radio galaxy. The redshift of a galaxy tells astronomers its distance because galaxies at greater distances move away from us at higher speeds, and this motion causes the galaxy’s light to shift farther into the red. Because light has a finite speed and takes time to reach us, more distant galaxies are also seen at earlier times in the history of the Universe.

The study was led by graduate students Aayush Saxena (Leiden Observatory, Netherlands) and Murilo Marinello (Observatório Nacional, Brazil), and the observations were obtained through Brazil’s participation in Gemini. “In the Gemini spectrum of TGSS J1530+1049, we found a single emission line of hydrogen, known as the Lyman alpha. The observed shift of this line allowed us to estimate the galaxy’s distance,” explains Marinello.

The relatively small size of the radio emission region in TGSS J1530+1049 indicates that it is quite young, as expected at such early times. Thus, the galaxy is still in the process of assembling. The radio emission in this kind of galaxy is powered by a supermassive black hole that is sucking in material from the surrounding environment. This discovery of the most distant radio galaxy confirms that black holes can grow to enormous masses very quickly in the early Universe.

The measured redshift of TGSS J1530+1049 places it near the end of the Epoch of Reionization, when the majority of the neutral hydrogen in the Universe was ionized by high-energy photons from young stars and other sources of radiation. “The Epoch of Reionization is very important in cosmology, but it is still not well understood,” said Roderik Overzier, also of Brazil’s Observatorio Nacional, and the Principal Investigator of the Gemini program. “Distant radio galaxies can be used as tools to find out more about this period.”

The research has been published by Monthly Notices of the Royal Astronomical Society.

See the full article here .

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Gemini/North telescope at Maunakea, Hawaii, USA,4,207 m (13,802 ft) above sea level

Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet


Gemini’s mission is to advance our knowledge of the Universe by providing the international Gemini Community with forefront access to the entire sky.

The Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai’i (Gemini North) and the other telescope on Cerro Pachón in central Chile (Gemini South); together the twin telescopes provide full coverage over both hemispheres of the sky. The telescopes incorporate technologies that allow large, relatively thin mirrors, under active control, to collect and focus both visible and infrared radiation from space.

The Gemini Observatory provides the astronomical communities in six partner countries with state-of-the-art astronomical facilities that allocate observing time in proportion to each country’s contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the Canadian National Research Council (NRC), the Chilean Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT), the Australian Research Council (ARC), the Argentinean Ministerio de Ciencia, Tecnología e Innovación Productiva, and the Brazilian Ministério da Ciência, Tecnologia e Inovação. The observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.