OSIRIS – A Darker View

W. M. Keck Observatory press release…

University of Hawaii at Manoa astronomer Regina Jorgenson has obtained the first image that shows the structure of a normal galaxy in the early universe as captured by the W. M. Keck Observatory. The results were presented at the winter American Astronomical Society meeting being held this week near Washington, DC.

The galaxy, called DLA2222-0946, is so faint that it is virtually invisible at all but a few specific wavelengths. It is a member of a class of galaxies thought to be the progenitors of spiral galaxies like our own Milky Way.

These galaxies are known to contain most of the neutral gas that is the fuel for star formation, so they are an important tool for understanding star and galaxy formation and evolution. Discovered and classified over 30 years ago, they have been notoriously difficult to see directly.

Dr. Jorgenson, an NSF Astronomy and Astrophysics Postdoctoral Fellow at the University of Hawaii’s Institute for Astronomy, worked with Dr. Arthur Wolfe of the University of California, San Diego. They used the advanced technologies of the W. M. Keck Observatory on Mauna Kea to obtain the first-ever spatially resolved images of a galaxy of this type.

The galaxy was detected with the 10-meter, Keck I telescope fitted with OSIRIS and the Laser Guide Star Adaptive Optics system.

Continue reading “First Detailed Look at a Normal Galaxy in the Very Early Universe”

An incredible amount of planning and work went into the job, with everything culminating in a few days of frenetic activity. Often referred to as “twins”, the Keck telescopes seem anything but. Over the years these once identical twins have taken on their own characteristics. One of the things that differentiates the two, each has its own set of unique instruments. Cameras and spectrographs, these multimillion dollar devices allow the recording and studying of the light collected by the massive 10-meter mirrors. This week we moved one of these instruments from Keck 2 to Keck 1… OSIRIS.

OSIRIS is an infrared integral field spectrograph. Designed to take full advantage of the Keck Adaptive Optics systems, the instrument has a relatively small field of view. Within that small field it does amazing things, providing a simultaneous spectrum and image of an object. Essentially it takes a stack of images at the same time, each at a different wavelength. This gives astronomers a very powerful tool. One image will show the distribution of particular elements throughout an object. Using doppler shift, an astronomer can also observe how everything is moving within the object as well.

The Keck crew lowering OSIRIS into Keck 1 AO

Moving an instrument is not a trivial job. It is not simply a matter of unplugging the instrument and moving it to the other telescope. Each instrument has a tremendous amount of infrastructure required to support it. Electrical wiring, optical fibers, plumbing for the cooling systems, support computers, and more… All of it has to be moved.

OSIRIS has been a removable instrument, mounted to a handling cart for easy removal and installation into the telescope. The new installation will be a permanent mount within the AO enclosure. A new mount must be designed and fabricated. New support beams welded and bolted into place. There are openings to be cut into the floor for the mounts and support connections. Then all of the electrical, optical cabling and plumbing run through the structure of the telescope. This all has to be designed, reviewed and then the modifications performed without interfering with nightly observing. The amount of work is truly daunting, and thanks to the efforts of a great crew, now complete.

Continue reading “The Flight of OSIRIS”