Most Distant Galaxy Discovery By University of California Astronomers
Astronomers from the University of California at Riverside published a paper in the October 2013 issue of the journal Nature saying that they have discovered the most distant galaxy so far. And the oldest galaxy too!
In the study entitled “A galaxy rapidly forming stars 700 million years after the Big Bang at redshift 7.51”, Galaxy z8_GND_5296 was formed 700 million years after the Big Bang, when the universe was just 5 percent of its current age.
From thousands of galaxies, the researchers reported a deep near-infrared spectroscopic survey of 43 photometrically-selected galaxies. They use color to select the galaxies.
Paper abstract:
Of several dozen galaxies observed spectroscopically that are candidates for having a redshift (z) in excess of seven, only five have had their redshifts confirmed via Lyman ? emission, at z = 7.008, 7.045, 7.109, 7.213 and 7.215. The small fraction of confirmed galaxies may indicate that the neutral fraction in the intergalactic medium rises quickly at z?>?6.5, given that Lyman ? is resonantly scattered by neutral gas. The small samples and limited depth of previous observations, however, makes these conclusions tentative. Here we report a deep near-infrared spectroscopic survey of 43 photometrically-selected galaxies with z?>?6.5. We detect a near-infrared emission line from only a single galaxy, confirming that some process is making Lyman ? difficult to detect. The detected emission line at a wavelength of 1.0343 micrometres is likely to be Lyman ? emission, placing this galaxy at a redshift z = 7.51, an epoch 700 million years after the Big Bang. This galaxy’s colours are consistent with significant metal content, implying that galaxies become enriched rapidly. We calculate a surprisingly high star-formation rate of about 330 solar masses per year, which is more than a factor of 100 greater than that seen in the Milky Way. Such a galaxy is unexpected in a survey of our size, suggesting that the early Universe may harbour a larger number of intense sites of star formation than expected.