S. Drew Chojnowski's Home Page


  • My CV (probably outdated)


I run the target selection & plate design pipeline for APOGEE (Apache Point Observatory Galactic Evolution Experiment), which is one of three surveys comprising the third installment of SDSS (Sloan Digital Sky Survey). Simply put, my job entails putting together lists of 265 stars, mainly red giants, that will be observed one or more times by the APOGEE + 2.5m SDSS telescope. More specifically I maintain and operate a series of IDL scripts that (a) gather data from previous surveys and instruments including 2MASS, WISE, SPITZER-IRAC, NOMAD, and TYCHO-2, (b) trim down the number of potential targets by making quality cuts and using dereddened colors to identify likely red giants, and (c) generate final target lists that are then used by NYU to create plate drilling plans for UW, which is where the actual drilling of plates occurs. These plates are subsequently shipped to the telescope at Apache Point Observatory and used in APOGEE observations.

I also do quality assessment, spot checking, and general analysis of APOGEE data. I take pride in helping to ensure consistent, high-quality data, and also in pointing out unusual data and participating in any subsequent follow-up efforts.

Be Stars:

One significant bonus of having to correct APOGEE spectra for H-band telluric absorption is that 35/300 fibers in each APOGEE observation are reserved for telluric standards (the bluest, and ideally, hottest stars in each field) whose presumably smooth continua allow for removal of telluric contamination from spectra of cooler stars. I am leading a project attempting to characterize and classify the spectra of Be-type emission-line stars which frequently contaminate the groups of telluric standards for many disc and bulge fields. In only one year of operation, APOGEE has already accumulated the largest ever sample (>300 observations of >80 Be stars) of high-resolution, H-band Be star spectra.

Giant clouds of AGN-ionized gas:

Beginning with my participation in the SARA REU at Alabama, I have worked with Dr. Bill Keel, participants in the Galaxy Zoo project, and other Galaxy Zoo scientists to find and study objects similar to Hanny's Voorwerp. The Voorwerp, or 'object,' has been shown to be a galaxy-sized cloud of gas still glowing some 70,000 years after the sudden death of the nearest quasar to Earth. From 2009-2010, Galaxy Zoo participants inspected images of ~16,000 AGN in hopes of finding similar objects. In 2010, we gathered long-slit spectra (KPNO 2m/GoldCam and Lick 3m/Kast) of the 35 or so best candidates. Emission line regions extending >10kpc from host nuclei were confirmed around 19 of the 35 targets. While it is difficult to rival the novelty of Hanny's Voorwerp, several of these 19 systems appear to be additional examples of 'recent' AGN fading. In 2011, we were granted 21 Hubble Space Telescope (HST) orbits for continuum and emission line imaging of the best seven Voorwerp analogues. Some of these images are among the weirdest ever delivered by HST.




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