THE MANGA INTEGRAL FIELD UNIT FIBER FEED SYSTEM FOR THE SLOAN 2.5 M TELESCOPE

By N. Drory, N. MacDonald, M. Bershady, K. Bundy, J. Gunn, D. Law, Michael J. Smith, R. Stoll, Christy A. Tremonti, D. Wake and 15 more. 2014

328 citations recorded by the source corpus.

We describe the design, manufacture, and performance of bare-fiber integral field units (IFUs) for the SDSS-IV survey Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) on the the Sloan 2.5 m telescope at Apache Point Observatory. MaNGA is a luminosity-selected integral-field spectroscopic survey of 104 local galaxies covering 360–1030 nm at R ∼ 2200 ?> . The IFUs have hexagonal dense packing of fibers with packing regularity of 3 μm (rms), and throughput of 96 ± 0.5% from 350 nm to 1 μm in the lab. Their sizes range from 19 to 127 fibers (3–7 hexagonal layers) using Polymicro FBP 120:132:150 μm core:clad:buffer fibers to reach a fill fraction of 56%. High throughput (and low focal-ratio degradation (FRD)) is achieved by maintaining the fiber cladding and buffer intact, ensuring excellent surface polish, and applying a multi-layer anti-reflection (AR) coating of the input and output surfaces. In operations on-sky, the IFUs show only an additional 2.3% FRD-related variability in throughput despite repeated mechanical stressing during plate plugging (however other losses are present). The IFUs achieve on-sky throughput 5% above the single-fiber feeds used in SDSS-III/BOSS, attributable to equivalent performance compared to single fibers and additional gains from the AR coating. The manufacturing process is geared toward mass-production of high-multiplex systems. The low-stress process involves a precision ferrule with a hexagonal inner shape designed to lead inserted fibers to settle in a dense hexagonal pattern. The ferrule ID is tapered at progressively shallower angles toward its tip and the final 2 mm are straight and only a few microns larger than necessary to hold the desired number of fibers. Our IFU manufacturing process scales easily to accommodate other fiber sizes and can produce IFUs with substantially larger fiber counts. To assure quality, automated testing in a simple and inexpensive system enables complete characterization of throughput and fiber metrology. Future applications include larger IFUs, higher fill factors with stripped buffer, de-cladding, and lenslet coupling.

Subfields: Astronomy and Astrophysics, Instrumentation, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/3ae08bab09ddefc7307153e3a9ac0999fcab150a

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Citations in the corpus

The Fifteenth Data Release of the Sloan Digital Sky Surveys: First Release of MaNGA-derived Quantities, Data Visualization Tools, and Stellar Library (2018, methodology): “The MaNGA survey uses a custom built instrument (Drory et al. 2015) which feeds fibers from a suite of hexagonal bundles into the BOSS spectrograph (Smee et al. 2013).”
SDSS IV MaNGA – metallicity and nitrogen abundance gradients in local galaxies (2017, methodology): “The core of the MaNGA instrument (Drory et al. 2015) consists of a set of 17 hexagonal fibre bundle integral field units (IFUs) of various sizes (ranging from a 19-fibre IFU, 12′′ on sky diameter, to a 127-fibre IFU, 32′′ on sky diameter), simultaneously deployed across the 3◦ diameter field of…”
THE DATA REDUCTION PIPELINE FOR THE SDSS-IV MaNGA IFU GALAXY SURVEY (2016, methodology): “This is measured during the manufacturing process to a typical accuracy ∼ 0.3µm (relative)45 and ∼ 5µm (absolute) (see Drory et al. 2015) and recorded in mangacore for each harness serial number.”
SDSS-IV MaNGA : the impact of diffuse ionized gas on emission-line ratios, interpretation of diagnostic diagrams and gas metallicity measurements (2016, methodology): “The fiber feed system has been re-designed (Drory et al. 2015) to accommodate 1423 fibers that are bundled into five 127-fiber bundles, two 91-fiber bundles, four 61-fiber bundles, four 37-fiber bundles, two 19-fiber bundles, twelve 7-fiber minibundles, and 92 sky fibers.”
SDSS IV MaNGA – spatially resolved diagnostic diagrams: a proof that many galaxies are LIERs (2016, methodology): “The MaNGA instrument suite is mounted on the SDSS 2.5m telescope at APO (Gunn et al. 2006) and is described in Drory et al. (2015) MaNGA target galaxies are divided in a ‘primary’ and a ‘secondary’ sample, following a 3:1 ratio.”
The SDSS-IV MaNGA Sample: Design, Optimization, and Usage Considerations (2017, background): “…of Physics and Astronomy, University of Utah, 115 S. 1400 E., Salt Lake City, UT 84112, USA scope (Gunn et al. 2006) and the BOSS spectrographs (Smee et al. 2013) with its fibers bundled into multiple IFUs (Drory et al. 2015) to measure spatially resolved spectroscopy of ∼10,000 nearby galaxies.”
SDSS-IV/MaNGA: SPECTROPHOTOMETRIC CALIBRATION TECHNIQUE (2015, methodology): “′′36 root-mean-square positional error on the target (see Drory et al. 2015 for the detailed error stack up), as compared to the 2′′ diameter fibers used in SDSS-III and IV.”
Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe (2017, methodology): “New in SDSS-IV, six of the nine APOGEE cartridges have an additional short fiber system for MaNGA that interfaces with the BOSS spectrographs (Drory et al. 2015).”
OBSERVING STRATEGY FOR THE SDSS-IV/MaNGA IFU GALAXY SURVEY (2015, methodology): “In accord with these predictions, the prototype circular 15 A conservative estimate can be made by comparing Figure 4 of Croom et al. (2012) to Figure 11 of Drory et al. (2015): MaNGA achieves 95 ±1 % throughput with an exit f-ratio of f/4 for fibers fed at f/5.”