The most distant galaxy in the 'cosmic dawn' (the early universe), SXDF-NB1006-2, has recently been discovered by the Subaru telescope.
SXDF-NB1006-2 is at a slightly greater distance than GN-108036, a galaxy, which until recently held the position of the most distant galaxy, was also discovered by the Subaru telescope.
Astronomers have verified that the proportion of neutral hydrogen gas in the 750-million-year-old early universe used to be higher than it is at present. This helps us understand the nature of the early universe during the cosmic dawn, when the light of ancient celestial objects appeared from the darkness.
The Subaru and Keck telescopes were used to discover SXDF-NB1006-2, which is 12.91 billion light years away from earth. The acronym SXDF stands for the Subaru/XMM-Newton Deep Field. The team of astronomers were from various institutes in Japan like Masanori Iye from National Astronomical Observatory of Japan, Takatoshi Shibuya from Graduate University for Advanced Studies, Japan, Nobunari Kashikawa from National Astronomical Observatory of Japan and Kazuaki Ota from Kyoto University. It took them 37 hours of observation in seven nights in two wide fields to find this elusive galaxy.
Spectroscopic observations were necessary to confirm the nature of the two candidates they had found for the position of 'farthest galaxy'. Two galaxies were observed with two spectrographs - the Faint Object Camera and Spectrograph (FOCAS) on the Subaru telescope and the Deep Imaging Multi-Object Spectrograph (DEIMOS) on the Keck II telescope. They identified one, which gave off the characteristic emission of distant galaxies and concluded that about 80 per cent of the hydrogen in the ancient universe 12.91 billion years ago was neutral i.e. astronomers think that the universe began 13.7 billion years ago due to the Big Bang.
About 200 to 500 million years after the Big Bang, the dense parts of neutral hydrogen clouds contracted under their own gravity forming the first stars and galaxies. The team's research was focused on identifying the exact epoch of the cosmic dawn in an effort to answer various astronomical questions about the history of our universe. While finding a galaxy at a critical epoch is exciting, it is not sufficient to characterise the entire epoch.
Precise measurement of the number of galaxies present during the cosmic dawn requires surveys of even wider fields with faster and more sensitive instruments.
The cosmic dark age began when hot cosmic plasma composed of protons and electrons recombined to form neutral hydrogen atoms within 380,000 years after the Big Bang. The team also hoped to conduct a survey of distant galaxies and measure their number and brightness. A vast area was searched; initially using the prime focus camera mounted on the Subaru telescope (suprime-cam).
The suprime-cam, complete with its new highly sensitive detectors, was attached to the NB1006 filter to observe two specifically designated regions of the sky: the Subaru deep field and the Subaru XMM-Newton deep survey field.
The scheduled 2012 installation of Subaru's new instrument, the hyper suprime-cam (HSC), will allow researchers to view a field seven times greater than that of suprime-cam opening the door to a huge galaxy sample. Observations with the HSC are steps on the path of uncovering the dark periods of the universe.
SXDF-NB1006-2 is at a slightly greater distance than GN-108036, a galaxy, which until recently held the position of the most distant galaxy, was also discovered by the Subaru telescope.
Astronomers have verified that the proportion of neutral hydrogen gas in the 750-million-year-old early universe used to be higher than it is at present. This helps us understand the nature of the early universe during the cosmic dawn, when the light of ancient celestial objects appeared from the darkness.
The Subaru and Keck telescopes were used to discover SXDF-NB1006-2, which is 12.91 billion light years away from earth. The acronym SXDF stands for the Subaru/XMM-Newton Deep Field. The team of astronomers were from various institutes in Japan like Masanori Iye from National Astronomical Observatory of Japan, Takatoshi Shibuya from Graduate University for Advanced Studies, Japan, Nobunari Kashikawa from National Astronomical Observatory of Japan and Kazuaki Ota from Kyoto University. It took them 37 hours of observation in seven nights in two wide fields to find this elusive galaxy.
Spectroscopic observations were necessary to confirm the nature of the two candidates they had found for the position of 'farthest galaxy'. Two galaxies were observed with two spectrographs - the Faint Object Camera and Spectrograph (FOCAS) on the Subaru telescope and the Deep Imaging Multi-Object Spectrograph (DEIMOS) on the Keck II telescope. They identified one, which gave off the characteristic emission of distant galaxies and concluded that about 80 per cent of the hydrogen in the ancient universe 12.91 billion years ago was neutral i.e. astronomers think that the universe began 13.7 billion years ago due to the Big Bang.
About 200 to 500 million years after the Big Bang, the dense parts of neutral hydrogen clouds contracted under their own gravity forming the first stars and galaxies. The team's research was focused on identifying the exact epoch of the cosmic dawn in an effort to answer various astronomical questions about the history of our universe. While finding a galaxy at a critical epoch is exciting, it is not sufficient to characterise the entire epoch.
Precise measurement of the number of galaxies present during the cosmic dawn requires surveys of even wider fields with faster and more sensitive instruments.
The cosmic dark age began when hot cosmic plasma composed of protons and electrons recombined to form neutral hydrogen atoms within 380,000 years after the Big Bang. The team also hoped to conduct a survey of distant galaxies and measure their number and brightness. A vast area was searched; initially using the prime focus camera mounted on the Subaru telescope (suprime-cam).
The suprime-cam, complete with its new highly sensitive detectors, was attached to the NB1006 filter to observe two specifically designated regions of the sky: the Subaru deep field and the Subaru XMM-Newton deep survey field.
The scheduled 2012 installation of Subaru's new instrument, the hyper suprime-cam (HSC), will allow researchers to view a field seven times greater than that of suprime-cam opening the door to a huge galaxy sample. Observations with the HSC are steps on the path of uncovering the dark periods of the universe.