APOGEE observed its first astronomical object on Jan 17th 2011 using the full optical system of the instrument, from fibers to the CCDs. This is a major milestone for one of the largest infra-red spectrographs ever built. Soon the instrument will be shipped to Apache Point Observatory for installation and integration with the SDSS telescope; stay tuned for more data from APOGEE.

The two images below show the solar spectrum observed by APOGEE. The first is the raw data taken from the CCD detectors; the dark grey bands are four groups of 30 fibers (or spectra) each, i.e., 120 spectra of the Sun in total. The second image is a plot of the extracted, one-dimensional spectrum of the Sun showing the infrared brightness of sunlight as a function of wavelength. The data still need calibrating but the many features around 1800, 2800 and 3000 pixels (x-axis) in the spectrum are well-known absorption bands caused by methane and cardon dioxide in our atmosphere. The drops to zero in the spectrum (at 2100 and 4400 pixels) are caused by gaps between the CCD detectors and are therefore not a real features in the Sun spectrum.

Raw data from APOGEE of the Sun

Solar spectrum. First astronomical light seen by APOGEE

More photos and technical details at http://www.astro.virginia.edu/~jcw6z/firstlab/ Congratulations to the APOGEE team!

Benjamin Clark, a high school student from Pennsylvania, has won the $100K Siemens Science award for 2010.

http://www.siemens-foundation.org/en/competition.htm

Ben has worked with Cullen Blake at Princeton University on a project related to low-mass binary stars in SDSS data. Ben used the individual 15-minute spectra of SDSS stars to search for very short period binary systems. He then conducted a Monte Carlo simulation to estimate the efficiency with which such systems can be detected and estimated their overall rate of occurrence.

Astronomers release the largest color image of the sky ever made

We provide here the AAS press release and supplementary material and links.

This past week the APOGEE hardware team jumped another hurdle by installing the slithead and the first 120 fibers into the APOGEE instrument. These are the so-called “long-links”, which are 40 meters long and connect the spectrograph (in a separate room) to the SDSS telescope.

Four spools of bundled fibers (30 per "cable" giving 120 in total) containing the fully manufactured long-links. They are being fed into the cryostat assembly clean tent.

The fibers are routed through the cryostat wall, looped through cooling trays, and then held securely in place with the s-tracks shown before reaching the spectrograph slithead

Close up of the slithead. After passing through the ends of the s-tracks (at upper left) the bare fibers (copper-colored) are splayed out and terminated within grooved blocks that are aligned to make sure the end of each fiber is in its proper location. The image shows the first three blocks (90 total fibers) in place.

SDSS was featured on the BBC “Joy of Stats” programme made by Wingspan Productions . Connie Rockosi (SDSS-III SEGUE-II Survey PI) was interviewed about how discoveries are made in the wealth of SDSS data, all freely available on the internet.

2.5m Observing Log, 12/3/2010 Night Observers: Audrey Simmons, Dmitry Bizyaev

A “model” SDSS-III night: seeing ~ 1″, clear sky, ALL plates plugged (8) were finished from scratch.

The key to all of the SDSS spectroscopic surveys has been multiplexing at an unprecedented scale. The original SDSS spectrographs were fed by fiber plugplates with 640 optical fibers. For the Baryon Oscillation Spectroscopic Survey (BOSS) of SDSS-III, this number was upped to 1000 fibers per plate. Under excellent conditions, a complete BOSS observation takes about an hour, including three fifteen minute “science exposures,” calibration observations, and the time required to swap one plugplate cartridge for another on the back of the telescope.

The light of sunset comes through a BOSS cartridge attached to the bottom of the APO 2.5-m telescope (still in its enclosure). Strands visible in silhouette are individual optical fibers that transmit the light of BOSS targets from holes in the fiber plugplate to the spectrographs, which are themselves mounted on the back of the telescope.

When the seeing isn’t needle-sharp or a thin layer of cirrus obscures the sky, it takes more exposures to measure the redshifts and absorption spectra of the faint galaxies and quasars that are the targets of BOSS. Many nights have intervals of clouds or poor seeing, and often there are holdover plates that were observed but not completed the previous night.

But every once in a while, things are perfect, like the night of December 2, 2010. Eleven hours, eight plates, every one done from start to finish. By the morning of December 3, BOSS was richer by 8,000 spectra, the largest one night haul in the history of the SDSS.

Of course, observing eight plates in a night means that our fiber plugging specialists have 8,000 new tasks for the next day. We have placed a rush order for extra liniment. A ninth BOSS cartridge went into service on the night of December 3 (!), so when the next perfect night arrives, we can aim for a clean 9,000.

Congratulations to the SDSS-III observing and telescope team.

Written by David Weinberg

The MARVELS team have published the discovery of a new short-period brown dwarf candidate around the star TYC 1240-00945-1. Below is the phased radial velocity curve TYC 1240-00945-1 with the Keplerian orbit solution. The MARVELS discovery data is in blue, with confirmation data in red (HET data) and purple (SMARTS). The bottom panel shows the residuals between the data points and the orbital solution.

radial velocity curve of MARVELS-1b

Above is the first spectrum taken with the SDSS-III APOGEE spectrograph, that for a krypton discharge lamp.

This spectrum was made under warm conditions and using a InGaAs detector with pixels two times larger than the actual APOGEE detectors will deliver. A series of separate images were taken, stepping along the dispersion direction in the spectrograph focal plane, and were then mosaic’ed together to make this final image. Several examples of these individual images are shown in the postage stamps in the upper corners. The lines in the spectrum are color coded by the final APOGEE detector on which they are expected to fall (blue, middle, red).

Analysis of this spectrum (by David Nidever), although undersampling the spectrograph resolution, suggests that the instrument is performing to specification.

Congratulations to the hardworking instrument team for this great progress!

Martin White and collaborators have submitted for publication one of the first SDSS-III BOSS science papers. The paper entitled “The clustering of massive galaxies at z~0.5 from the first semester of BOSS data” uses some of the first data ever taken for BOSS last year to look at how the galaxies they are selecting populate the underlying “dark matter halos” that we believe enshroud all galaxies and clusters of galaxies. Using the first measurements of the clustering of BOSS galaxies, compared to detailed simulations of the BOSS survey, White et al. were able to show that 90% of BOSS galaxies were preferentially located to at the centers of their dark matter halos and thus excellent tracers of those halos . This is one of the main assumptions of BOSS and therefore re-assuring to check! There is still a long way to go, but it is good to see BOSS producing results. The full paper is available on the arXiv preprint server but we provide below a snapshot of the title, authors and abstract. Enjoy.

We all had fun at the Paris SDSS-III collaboration meeting and provide here a selection of photos.

Team photo of attendees (thanks to Adrian Price-Whelan)

The APOGEE spectrograph is coming together with the last of the optics installed early October. The camera optics and mechanics were designed and integrated by New England Optical Systems (NEOS). It features four pure silicon and a pair of fused silica lenses with the largest lens approximately 400 millimetres. It was installed along side of the VPH grating which itself is the largest mosaic grating of its kind. After installation, the optics will be warm aligned and tested. The first “cool-down” of APOGEE is less than two weeks away!

(Photos from Fred Hearty. Thanks!)

The camera coming out of the crate

Moving camera into the clean tent

The cover is off

In the spectrograph now!

No, not a location suggestion for the next SDSS-III collaboration meeting but an observation by SDSS-III scientist Eyal Kazin (NYU) who was shocked to encounter the SDSS at the Stefanik Observatory on a recent trip to visit friends. He writes:

They display astronomy in general, and cosmology in particular, and I was very happy to see that SDSS is recognized in association with galaxy mapping. I just wanted to share with you the photo I took. You can see the 2.5m telescope, as well as a pie chart created, I believe, by Michael Blanton, as well as the Sloan-Great wall.

The last of the sdss3 instruments is making rapid progress and will soon be on the sky. Photographs below from Fred Hearty at the University of Virginia (UVa) show the delivery of the cryostat at UVa during July. The 4,000 pound instrument was manufactured by Basil Blank at PulseRay in Beaver Dams NY and just barely fit in the truck and the UVa labs.

The two images below show the spectrograph components being integrated into the cryostat. The VPH grating in its mount is in the background as it was being positioned, as well as the Fold 1 Mirror and Collimator (left and right foreground respectively). A close-up of the VPH – only large format mosaic VPH in the world – is shown in a closeup. The final two optics (Fold 2 and Camera) are fabricated and will be installed next week (Sept 2010). The detector array, which is in safe keeping at UVa, will be installed after the first thermal cycle of all major optics.

Ann Finkbeiner has now written the history of the original Sloan Digital Sky Survey, with a nod to SDSS-II and SDSS-III. The publication date is August 17 2010, and can be found at a number of booksellers .

Below is the cover of the SDSS book A Grand and Bold Thing .

The new SDSS-III website has been launched. This includes up-to-date information on the surveys, data releases and instrumentation (including photos), all the important SDSS-III collaboration documents (publication policy, PoO and the external collaborators policy) and updates and links to the SDSS-III blog and press releases.