MEGARA: a new generation optical spectrograph for GTC

Research Projects
Organizational Units
Journal Issue
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.
Conference on Ground-Based and Airborne Instrumentation for Astronomy (5th. 2014. Montreal, Canada). © 2014 SPIE, the international society for optics and photonics.
Unesco subjects
[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)