GeminiFocus January 2018 - Page 13

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 .
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Figure 3. 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,” com- mented Gemini’s Peter Michaud. “That’s why it’s such a mystery.” According to Bañados, spectroscopic data from the Gemini Near-InfraRed Spectrom- eter (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 mag- nesium lines are emitted at ultraviolet wave- lengths, 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 con- straining 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 on- set of quasar activity. It is unknown precisely how many quasars as distant as this one ex- ist over the whole sky. Bañados and his team plan to continue searching for similar qua- sars using Gemini and other large telescopes around the world. January 2018 Sifting Supernovae from the Dust in LIRGs Combined Magellan/ FIRE and Gemini/ GNIRS near-infrared spectrum of the quasar J1342+0928. The ins )́͡ѡ5%$)ݡ啐Ս)ɽѕɵ)ѡ́ѡ)݅́х)ͥ9%IL)хȁɝȁѡЁЁѥ́ѡ)́ȁMո́ѕѼ)́qɔ͔ɹهt M8)!ݕٕȰݕȁѡ͔ͥ́ɔ)͕ٕѡɔѕ͕)չхѡɅѕ́ѕȁѠ)ٽѥͥѥ)ѡɍٕЁ M9́́ѡа)͔ѡѥ́Ս́х)ɔͼ͡аѡ͔ٕ́ȁݥѡɔ)́ѕ͔хȁɵѥݡɔ)͍ɕ́ѡѥиQɥ)ݕ͕مѥ́хѥ́)ѥձɱ䁅ɕЁյ́Ʌɕ)ᥕ̀1%I̤ݡɴх́Ёٕ)Ʌѕ́ɕ́ݥѠɝչ)͍ɥаݡձѼ)ͥЁɅѥ M9́ɕ)չ͍ٕɕ)Qѡqͥtɹمѕȴ)ѥѕɽ́ɭ)AɽЁMU9 %Iݡх́+qMɹمU9ͭ %ɅI)ѕѥtQɽа -)5ՅɥUٕͥ䁥Ʌ)ѽ́1%ILݥѠѡMѠѥٔ)=ѥ́%ȀM=$͕ݥѠѡ)5ձѤ՝єѥٔѥ́Mѕ(5LMѠ 䁽͕٥)ݥѠ5LM=$ѡȵɅɕ)ٕ݅Ѡȸԁɽ̰ݡɔѡ)ѕЁ́Ս́ѕ䁑)(