The NAHUAL project
NAHUAL is a planed second-generation instrument for the 10-m-GTC (Gran Telescopio
CANARIAS) telescope which is now almost completed at the
Observatorio del Roque de los Muchachos on the island of La Palma.
NAHUAL will be a general facility high-resolution near infrared (IR)
spectrograph. The main science drivers of this instrument are (1.) high
precision radial velocity measurements for the search of exo-planets
around late type stars and brown dwarfs; (2.) the study of the
atmospheres of brown dwarfs; (3.) chemical abundance studies; (4.) the
study of stellar activity, especially measurements of the magnetic field
strength of late type objects (5.) circumstellar disks; (6.) high
precision radial velocity measurements for asteroseismology of cool
stars. Secondary science drivers are the study the objects within the
solar-system, of the interstellar matter, and of gamma ray bursters.
Currently a feasibility study is being carried out. While the details
of the instrument are subject to the results of the feasibility study,
the main technical requirements have already been defined. In contrast
to other high resolution IR spectrographs, this instrument will be
especially be designed to achieve the highest possible accuracy for
radial velocity measurements. The goal is to reach an accuracy of about
1 m/s. It is thus required that the instrument is being cross-dispersed,
so that at least one spectral band (J, H, or K) is covered. Absorption
cells will be placed in front of the slit which will allow a
simultaneous self-reference similar to an I2-cell in the optical
regime. A laboratory testbed for the development of such cells has been
set up at the IAC in collaboration with the chemistry department of the
University of La Laguna. It is planned to place the instrument at the
Nasmyth platform of the GTC so that it can be fed by the AO-system. It
is currently foreseen that the instrument should reach a two-pixel
resolution of up to lambda /Dlambda of 80,000 with an image-slicer and a
2kx2k detector. A future upgrade foreseen the use of an AO-system and a
4kx4k detector, once these become available.
Articles
NAHUAL: a near-infrared high-resolution spectrograph for the GTC
optimized for studies of ultracool dwarfs
(
download)
NAHUAL: A cool spectrograph for planets
of ultra-cool objects
(
download)
Meetings
The first NAHUAL
meeting was held June 10-12, 2004 at the Parador Nacional de La
Gomera, the second NAHUAL meeting was held June 16-18, 2005 at the Parador Nacional de Segovia , and the
third meeting of the consortium will be held June 19-21, 2006 at
the old castle in Dornburg/Saale near Jena.
Fig. 1: The dome of the GTC telescope
Partner institutions:
Instituto de Astrofisica de Canarias, 38200 La Laguna, Tenerife, Spanien
LAEFF - INTA, PO Box 50727, 28080 Madrid, Spanien
IAA, Instituto de Astrofisica de Andalucia, C/Camino Bajo de
Hu\etor, 24, 18080 Granada, Spanien
INAF - Osservatorio Astrofisico di Arcetri, Largo Fermi 5, 50125
Firenze, Italien
Thüringer Landessternwarte Tautenburg, Germany