The million-dollar question for today's cosmologists is when this second transition from neutral to ionized gas occurred. Spectrum of the newly discovered distant quasar, obtained with the Keck Telescope atop Mauna Kea in Hawaii. The spectrum represents 4.5 hours of integration. The vertical axis shows position on the sky. The vertical stripes evident on the spectrum are residuals from night sky lines, ie.
Horizontal stripes are sources.
The bottom source is a nearby galaxy emitting light from the blue to the red. As a quasar's light makes its journey toward us, the light is absorbed by any matter that lies in its path. The new quasar will also shed light on how matter was distributed at earlier stages of cosmic history. Because quasars are more luminous than distant galaxies at the same redshift, they act as the brightest flashlights, allowing us to study everything that has ever developed between us and the quasar. The recent findings were presented in an issue of the Astrophysical Journal Letters.