Figure 1 . Upper left : Hubble
Space Telescope ( HST ) image and intensity map of the lensed spiral galaxy A1689B11 . The
Gemini NIFS field-ofview is outlined . Upper right : Intensity map of redshifted Hα emission ( from an atomic transition in hydrogen ) as measured by NIFS .
Lower left : The
NIFS velocity map for hydrogen gas in A1689B11 , showing the rotation speed of
200 km / s . Lower right : NIFS velocity dispersion map , showing the dispersion ( velocity deviations ) from the smooth rotation . The velocity deviations are generally less than 10 % of the rotation velocity , indicative of a very orderly rotation pattern .
Big Bang . Most galaxies at such distances are irregular in appearance , and even the more regular ones generally lack evidence of ordered rotation when their kinematics are studied through integral-field spectroscopy . Thus , kinematic confirmation of the spiral nature of A1689B11 was essential .
Taking advantage of the gravitational magnification by a factor of 7 , the team of astronomers from Australia , France , and the United States ( led by Tiantian Yuan of Swinburne University ) used NIFS on Gemini North to map the internal gas distribution and velocity structure of A1689B11 ( Figure 1 ). Although the galaxy is furiously forming stars at a rate nearly 20 times that of the Milky Way ( similar to other galaxies of these early cosmic times ), the gas kinematics trace out a “ tranquil velocity field ” with an ordered rotation of 200 km / s , very close to the rotation speed of the Milky Way . They also show a very small dispersion about this mean value . This makes A1689B11 the most distant kinematically confirmed spiral , and only the second one at a distance beyond 10 billion light years . These primitive spirals mark the formation epoch of galaxies like our own Milky Way .
The team ’ s findings appear in a paper published in The Astrophysical Journal .
A Binary Supermassive Black Hole System Far Beyond Andromeda
Researchers from the University of Washington were searching Local Group galaxies for a “ still-theoretical class of exotic stellar binary ” composed of two red supergiant stars when they stumbled on what may be an even more exotic type of binary — one composed of a pair of supermassive black holes . The search , led by Trevor Dorn-Wallenstein , a doctoral student at the University of Washington , involved matching possible red supergiants with Chandra X-ray sources and turned up one object of interest , apparently residing in the outer disk of the spiral galaxy M31 , also known as the Andromeda Galaxy .
This chimera-like object , referred to as J0045 + 41 , had previously been classified in one study as an eclipsing stellar binary because of its optical variability . Other studies had classified it as a globular star cluster in M31 because of its brightness and noticeably extended appearance . Its X-ray properties were consistent with being either an X-ray emitting binary star in M31 or an active galactic nucleus ( AGN ) in the far background . In order to determine the true nature of J0045 + 41 , the team submitted a Fast Turnaround proposal to use the Gemini Multi-Object Spectrograph ( GMOS ) on Gemini North .
As reported in The Astrophysical Journal , the GMOS spectrum conclusively showed that J0045 + 41 is an AGN in a galaxy at a distance of 2.6 billion light years , more than a thousand times farther away than the Milky Way ’ s majestic neighbor ( Figure 2 ). And careful modeling of the broad hydrogen emission lines seen in the object ’ s spectrum turned up something even more surprising : evidence for two distinct massive objects orbiting each other with an extraordinary velocity of at least 4,800 km / s . In addition ,
38 GeminiFocus January 2018 / 2017 Year in Review