The GOYA Project studies the structure, dynamics and populations of galaxies at high redshift, with the aim of learning on the epoch and the mechanisms by which galaxies formed the bulk of their stars and acquired their present structure and dynamics.  We emphasize the use of NIR data which samples the rest-frame optical spectrum at high redshift.  We are building EMIR, a NIR cryogenic multi-slit spectrograph for the Spanish 10.4m GTC. The GOYA Project is led by scientists from the IAC, Universidad Complutense de Madrid, University of Florida, and University of Toulouse.

GOYA is currently working on the following projects:
 
 
 

GOYA Survey   Sample image from the GOYA Survey (Ks band, top) and corresponding field imaged with HST/WFPC2 (F814W, bottom)	We are conducting a NIR-visible survey ("the GOYA Survey") to map 0.5 square degree of high-latitude sky to limiting AB magnitude Ks=22 (5-sigma, 1 arcsec aperture), and corresponding depths at U,B,V,R,I,J, using 4-m class telescopes, as well as public data.  Fields surveyed include the Groth strip, the GOODS-N field, the SA68 field, the VVDS-2h field, and the COSMOS-10h field. To sort out the critical selection function that ensures a homogeneous selection process of galaxies at different redshifts we are conducting extensive simulations of synthetic and real images of galaxies.  We replicate galaxy images at varying redshift with cosmopack/cosmoshift, an IRAF package we have developed to apply K- and evolutionary corrections and to simulate the parameters of a given telescope-instrument setting.     GOYA is the key science driver for the EMIR spectrograph which we proposed for GTC. See below in this page. See also our EMIR site at Madrid/UCM.
Instrumentation - the EMIR project EMIR on the GTC Nasmyth platform	The GOYA team is the Science Team for EMIR, a NIR cryogenic multi-slit spectrograph currently under construction for the 10m GTC telescope at El Roque de los Muchachos Observatory.   EMIR is being built by IAC, UCM and LAOMP and is currently planned for delivery in 2009.  EMIR will provide imaging and multi-slit J, H and K spectroscopy for up to 50 targets using cryogenic multi-slit masks, at a resolution of R~4000.
Virial Galaxy Masses	It is a common-sense assumption that galaxies have built up their masses over time to achieve their present-day forms. While the stellar content of the universe should start at zero and grow as time passes, the exact form of this evolution is not trivial. It could reveal much about the interaction of large-scale cosmological physics and small-scale star-formation physics. Measuring the rate at which this mass build-up happened and learning the processes that shaped the galaxies are major goals of GOYA. Galaxy mass has also proven to be a key parameter in studies of galaxy evolution over cosmological timescales since it is independent on the amount of luminosity evolution. GOYA will allow to compare directly distant young galaxies at look-back times with today's stellar systems of similar mass and identify unambiguously their local counterparts. With EMIR we will estimate the internal kinematics of high redshift galaxies using emission-line velocity widths and rotational velocities traced by the ionized gas, as well as velocity dispersions measured from stellar absorption lines. Most GOYA fields have been -or will be- imaged by HST, which will provide measurements of actual galaxy sizes. Galaxy masses will be derived via the virial theorem applied to the kinematic and size measurements.
Barionic Galaxy Masses Red: ellipticals. Triangles: spirals. Open circles: starburst, LBCG galaxies.	Our UBVRIJK photometric photometry is ideally suited to determining barionic galaxy masses to z=1, by fitting synthetic spectral energy distributions computed from evolutionary population synthesis models. David Cristóbal has computed barionic stellar masses for samples of spirals, ellipticals and compact, starburst galaxies from the Groth strip, as part of his PhD research. His code fits a two-population, burst-bulge model composed from GISSELXX population models. The figure at left shows stellar masses vs the K-band absolute magnitude, for ellipticals, spirals and LBCG galaxies with 0.3<z<0.8. As expected, masses increase with the K-band luminosity. However, spirals and star-burst galaxies deviate from the relation defined by ellipticals (lower panel).
Star formation rate and physical properties of emission-line galaxies	The population of emission-line galaxies is essential to study key aspects of galaxy evolution. Visible-range spectrographs restrict current studies to luminous objects in the rest-frame ultraviolet: our knowledge of the high-z Universe is biased to those objects with strong emission in the Lyman-a region and the UV. Using EMIR, GOYA will carry out the first complete and systematic study of the emission-line galaxy population (including both active and star-forming) at the 1.4-2.8 redshift range. At z~2, the 1.5-2.5 μm range translates into rest-frame ~3300-8300Å, the region of the spectrum that has been most widely studied in nearby galaxies. The capability of EMIR to obtain spectroscopy in the NIR simultaneously for a considerable sample of sources, will be unique to extend previous surveys in the optical. GOYA will compare directly the properties of the high-z galaxies with those of the nearby population in the same parameter space including emission-line ratios, SFRs, metallicities and internal kinematics. This procedure avoids the uncertainties in the calibrations and biases that affect similar studies of high-z galaxies in the rest-frame UV. The GOYA Survey will also provide Hα and [NII]6548,6584 for the samples of galaxies at intermediate redshift (z 0.7 to 1.4) for which only [OII]3727 was observed in the optical. As a result, GOYA will measure Star Formation Rates using Hα as SFR tracer, and will obtain the SFR luminosity function of the Universe at redshifts from z=0.7 to z=2.8. GOYA will be also able to extend the analysis up to z~5.7 using the [OII]3727 emission line as a SFR tracer.
Galaxies at z>>5	GOYA will address the exciting new domain of the search and study of galaxies beyond z>~5, in particular in the z~7-11 range. The main characteristics of such extremely high-z starbursts are strong UV emission from stellar and nebular continua, and important recombination lines, mainly Lyman alpha and HeII 1640. Source candidates for subsequent spectroscopic follow up with EMIR/GTC will be selected using both narrow-band techniques ,or using photometric redshifts or simple Lyman-α seleections on ultra-deep, broad-band, near-IR and optical images. GTC/EMIR will allow an efficient spectroscopic follow up in the near-IR thanks to its intermediate resolution (R~4000), providing good OH-line subtraction, an enlarged spectral domain "free" of sky lines, increased contrast for non-resolved emission lines and an accurate measurement of line profiles. Such line profiles should allow a discrimination between starbursts and AGNs. The typical line fluxes expected for Lyman alpha and HeII 1640 in the relevant redshift and stellar-mass domains range between a few 10^{-18} and 10^{-17} erg/s/cm2. The GOYA Survey with EMIR should allow to study the physical properties of galaxies at very high-z. This includes the determination of the Cosmic SFR in a coherent way from z~0 to 6, using the [OII]3727 emission line calibrated on Hα, and the measurement of velocity fields allowing to determine masses and M/L ratios tracing the early epoch of mass assembly.