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MEGARA: a new generation optical spectrograph for GTC

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Abstract
MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is an optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) designed for the GTC 10.4m telescope in La Palma. MEGARA offers two IFU fiber bundles, one covering 12.5x11.3 arcsec^2 with a spaxel size of 0.62 arcsec (Large Compact Bundle; LCB) and another one covering 8.5x6.7 arcsec^2 with a spaxel size of 0.42 arcsec (Small Compact Bundle; SCB). The MEGARA MOS mode will allow observing up to 100 objects in a region of 3.5x3.5 arcmin^2 around the two IFU bundles. Both the LCB IFU and MOS capabilities of MEGARA will provide intermediate-to-high spectral resolutions (R_FWHM∽6,000, 12,000 and 18,700, respectively for the low-, mid-and high-resolution Volume Phase Holographic gratings) in the range 3650-9700 ÅÅ. These values become R_FWHM∽7,000, 13,500, and 21,500 when the SCB is used. A mechanism placed at the pseudo-slit position allows exchanging the three observing modes and also acts as focusing mechanism. The spectrograph is a collimator-camera system that has a total of 11 VPHs simultaneously available (out of the 18 VPHs designed and being built) that are placed in the pupil by means of a wheel and an insertion mechanism. The custom-made cryostat hosts an E2V231-84 4kx4k CCD. The UCM (Spain) leads the MEGARA Consortium that also includes INAOE (Mexico), IAA-CSIC (Spain), and UPM (Spain). MEGARA is being developed under a contract between GRANTECAN and UCM. The detailed design, construction and AIV phases are now funded and the instrument should be delivered to GTC before the end of 2016.
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Conference on Ground-Based and Airborne Instrumentation for Astronomy (5th. 2014. Montreal, Canada). © 2014 SPIE, the international society for optics and photonics.
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[1] Ortiz, R., et al., "Inverse analysis method to optimize the optic tolerances of MEGARA: the future IFU and Multi-Object Spectrograph for GTC", Proc. SPIE, this volume (2014) [2] Pérez Calpena, A., et al., "MEGARA fiber bundles", Proc. SPIE, this volume (2014a) [3] Pérez Calpena, A., et al., "System engineering at the MEGARA project", Proc. SPIE, this volume (2014b) [4] Castillo, E., et al., "MEGARA main optics opto-mechanics", Proc. SPIE, this volume (2014) [5] Ferrusca, D., et al., "MEGARA cryostat advanced design", Proc. SPIE, this volume (2014) [6] Carrasco, E., et al., "MEGARA Optical manufacturing process", Proc. SPIE, this volume (2014) [7] García Vargas, M.L., et al., "Project management for complex ground-based instruments: MEGARA plan", Proc. SPIE, this volume (2014) [8] Castillo Morales, A., et al., "MEGARA Control System", Revista Mexicana de Astronomía y Astrofísica (Serie de Conferencias) 42, 123 (2013) [9] Sheth, K., et al., "The Spitzer Survey of Stellar Structure in Galaxies (S4G)", Publications of the Astronomical Society of the Pacific 122, 1397-1414 (2010) [10]Egami, E., et al., "The Herschel Lensing Survey (HLS): Overview", Astronomy & Astrophysics 518, L12, 5 pp. (2010) [11] Gil de Paz, A., “MEGARA: the future optical IFU and multi-object spectrograph for the 10.4m GTC telescope”, Proc. of SPIE Vol. 8446, 84464Q (2012) [12] Gil de Paz, A., et al., "MEGARA: The future IFU and MOS of the 10.4 m GTC", Revista Mexicana de Astronomía y Astrofísica (Serie de Conferencias) 42, 90-92 (2013) [13] Carrasco, E., et al., "MEGARA spectrograph optics", Proc. of SPIE Vol. 8011, 80112D (2012)
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