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Title: SDSS-IV/MaNGA: Spectrophotometric calibration technique

Mapping Nearby Galaxies at Apache Point Observatory (MaNGA), one of three core programs in the Sloan Digital Sky Survey-IV, is an integral-field spectroscopic survey of roughly 10,000 nearby galaxies. It employs dithered observations using 17 hexagonal bundles of 2'' fibers to obtain resolved spectroscopy over a wide wavelength range of 3600-10300 Å. To map the internal variations within each galaxy, we need to perform accurate spectral surface photometry, which is to calibrate the specific intensity at every spatial location sampled by each individual aperture element of the integral field unit. The calibration must correct only for the flux loss due to atmospheric throughput and the instrument response, but not for losses due to the finite geometry of the fiber aperture. This then requires the use of standard star measurements to strictly separate these two flux loss factors (throughput versus geometry), a difficult challenge with standard single-fiber spectroscopy techniques due to various practical limitations. Thus, we developed a technique for spectral surface photometry using multiple small fiber-bundles targeting standard stars simultaneously with galaxy observations. We discuss the principles of our approach and how they compare to previous efforts, and we demonstrate the precision and accuracy achieved. MaNGA's relative calibration between themore » wavelengths of Hα and Hβ has an rms of 1.7%, while that between [N ii] λ6583 and [O ii] λ3727 has an rms of 4.7%. In using extinction-corrected star formation rates and gas-phase metallicities as an illustration, this level of precision guarantees that flux calibration errors will be sub-dominant when estimating these quantities. The absolute calibration is better than 5% for more than 89% of MaNGA's wavelength range.« less
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] ;  [11] ;  [2] ;  [12] ;  [13] ;  [10] ;  [1] ;  [14] ;  [15] ;  [16] more »;  [17] ;  [1] « less
  1. Univ. of Kentucky, Lexington, KY (United States). Dept. of Physics and Astronomy
  2. Univ. of Wisconsin, Madison, WI (United States). Dept. of Astronomy
  3. Space Telescope Science Inst., Baltimore, MD (United States)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physics Division
  5. Univ. of Tokyo (Japan). Kavli IPMU (WPI)
  6. Univ. of Texas, Austin, TX (United States). Dept. of Astronomy
  7. Univ. of Washington, Seattle, WA (United States). Dept. of Astronomy
  8. Apache Point Observatory, Sunspot, NM (United States); Moscow State Univ., Moscow (Russian Federation). Sternberg Astronomical Inst.
  9. Univ. of Chile, Santiago (Chile). Dept. of Astronomy; Center for Astrophysics and Related Technologies (CATA), Santiago (Chile); Observatories of the Carnegie Inst. for Science, Pasadena, CA (United States)
  10. New York Univ. (NYU), NY (United States). Center for Cosmology and Particle Physics
  11. Univ. of Toronto, ON (Canada). Dunlap Inst. for Astronomy and Astrophysics
  12. Princeton Univ., NJ (United States). Dept. of Astrophysical Sciences
  13. Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Astronomy
  14. National Autonomous Univ. of Mexico (Mexico). Inst. of Astronomy
  15. Univ. of Wisconsin, Madison, WI (United States). Dept. of Astronomy; Open Univ., Milton Keynes (United Kingdom). Dept. of Physical Sciences
  16. Univ. of St. Andrews, Scotland (United Kingdom). School of Physics and Astronomy
  17. Shanghai Astronomical Observatory (China)
Publication Date:
Grant/Contract Number:
AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Astronomical Journal (Online)
Additional Journal Information:
Journal Name: Astronomical Journal (Online); Journal Volume: 151; Journal Issue: 1; Journal ID: ISSN 1538-3881
Publisher:
IOP Publishing - AAAS
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; atmospheric effects; methods: observational; surveys; techniques: imaging spectroscopy
OSTI Identifier:
1378987