estimated mass 800 million times greater than that of our Sun . At this distance , the Universe was only about 5 % of its current age , or about 690 million years old . “ That ’ s not a lot of time for stuff to happen ,” commented Gemini ’ s Peter Michaud . “ That ’ s why it ’ s such a mystery .”
According to Bañados , spectroscopic data from the Gemini Near-InfraRed Spectrometer ( GNIRS ) on Gemini North were key in determining the mass for the supermassive black hole . “ We dove deep into the infrared light spectrum at Gemini and probed the magnesium lines ,” said Bañados . These magnesium lines are emitted at ultraviolet wavelengths , but at such large distances , they are “ redshifted ” into the infrared ( Figure 3 ). Among the instruments used in this study , only GNIRS was able to probe these lines , and they proved critical for accurately constraining the mass . These results , including the discovery , are presented in Nature .
The study also concludes that J1342 + 0928 existed at a time when the Universe was still emerging from the cosmic “ dark ages ” and entering the epoch of reionization , when neutral gas in intergalactic space became ionized by luminous young stars and the onset of quasar activity . It is unknown precisely how many quasars as distant as this one exist over the whole sky . Bañados and his team plan to continue searching for similar quasars using Gemini and other large telescopes around the world .
Sifting Supernovae from the Dust in LIRGs
A star larger than about eight times the mass of our Sun is expected to end its life as a “ core collapse supernova ” ( CCSN ). However , fewer of these explosions are observed than are expected based on our understanding of the rates of stellar birth and evolution . A possible explanation for the perceived deficit of CCSNs is that , because the lifetimes of such high-mass stars are so short , these events occur within regions of intense star formation , where dust obscures the optical light . The disparity between observations and expectations is particularly apparent in luminous infrared galaxies ( LIRGs ), which form stars at very high rates in regions with large amounts of obscuring dust , which could lead to a significant fraction of CCSNs remaining undiscovered .
To find the “ missing ” supernovae , an international team of astronomers embarked on Project SUNBIRD , which stands for “ Supernovae UNmasked By InfraRed Detection .” The project , led by E . C . Kool of Macquarie University in Australia , monitors LIRGS with the Gemini South Adaptive Optics Imager ( GSAOI ) used with the Gemini Multi-conjugate adaptive optics System ( GeMS ) on Gemini South . By observing with GeMS / GSAOI in the near-infrared at a wavelength of 2.15 microns , where the emitted light is much less affected by dust
Figure 3 . Combined Magellan / FIRE and Gemini / GNIRS near-infrared spectrum of the quasar J1342 + 0928 . The inset shows the Mg II line , which played a crucial role in determining the mass of the black hole and was obtained using GNIRS .
January 2018 GeminiFocus
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