NAHUAL: A CONCEPT FOR A HIGH RESOLUTION IR SPECTROGRAPH FOR A 10-M SEGMENTED TELESCOPE (GTC)

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1 NAHUAL: A CONCEPT FOR A HIGH RESOLUTION IR SPECTROGRAPH FOR A 10-M SEGMENTED TELESCOPE (GTC) Motivation: To extend the parameter space of planet searches (ages, masses, rotation). Very low-mass primaries (Martin et al. 2006, Blake et al. 2007, Zapatero Osorio et al. 2007, 2009) T Tauri stars (Huélamo et al. 2008), Young MS stars, Red giants Connections to ALMA & ELTs

2 Henry 1998 Martín et al m/s 0.1 m/s Required RV precision to detect 1 M E Kasting et al. (1995) NIR RV precision of 1 m/s needed to detect rocky planets in habitable region around late-m, L and T dwarfs

3 NAHUAL Team Eduardo Martín (PI), Maria Rosa Zapatero Osorio (CAB) Eike Guenther (co-pi), Artie Hatzes, Sylvio Klose (TLS) Carlos del Burgo (co-pi), Tully Peacoke (DIAS) Antonio Amorim, André Moitinho, J. Lima (Lisboa) Víctor S. Béjar, Enric Pallé, Florian Rodler, Luisa Valdivielso, Manuel Amate, Javier Fuentes, Darío Sosa (IAC) Pedro Esparza (Univ. La Laguna), Carlos Alvarez (GTC) Jose Antonio Caballero, David Montes (UCM) Carlo Baffa, Sofía Randich (Arcetri) Humberto Campins, Michele Montgomery, Rohit Deshpande, Ramarao Tata, Robert Peale (Univ. Central Florida) Science cases RV searches for habitable exoplanets in cool stars (late-m, L) Follow-up of exoplanet candidates in the IR (including transit spectroscopy) Magnetic activity in cool stars and brown dwarfs Rotation in cool stars and brown dwarfs Astroseismology Chemical abundances in stars and solar system objects Very low-mass binaries Very young binaries BD companions of WDs (including CVs) Stellar populations in the Milky Way and other galaxies Black holes in AGNs Gamma ray bursts

4 Community interest 7 workshops held so far (La Gomera, Segovia, Jena, Cádiz, Miami, Fuerteventura, Sintra) About 80 different participants in those workshops Seed for instrument proposed for Calar Alto 3.5-m (CARMENES) Need for high-precision RV capabilities mentioned in Exoplanet Task Force and Blue Dots reports. Funding collected since 2005: 600 Keuros from MEC 200 Keuros from Tautenburg 100 Keuros from IAC 40 Keuros from Lisbon Observing modes NAHUAL team driven: Single object. High stability (no moving parts). R=60,000. Wav. Range= microns. FOV=3 arcsec. GTC driven: Multi-object capability. R=20,000. Range= microns. FOV 10 arcmin. Could we find a compromise?

5 The NIRSPEC radial velocity data of LP has rms of 360 m/s. VB10 RV data has rms of 110 m/s in 8 continuous exposures (Martin et al ApJ) Long-term NIRSPEC RV data ( ) of VB10 has rms of 300 m/s Zapatero Osorio, Martin, et al. 2009, A&A Mass of companion 6.4 Jupiters; Pravdo & Shaklan 2009

6 What can we do to improve the precision? Deconvolution by F. Rodler 11 Nahual project web page GTC TELESCOPE NAHUAL Martín et al. 2005, AN

7 GTC GTC floating basement. Fiber-fed through folded Cass G. About 40 meters of fibers (98% transmission in Y,J,H, but only about 30% for K-band). AO Nasmyth platform (stringent constraints on space and weight because of other instruments). Coudé room (longer fibers, high stability). Folded cass (supported by GTC, high throughput). White Pupil Baseline Optical Design for NAHUAL FIRST STAGE: HIGH DISPERSION SECOND STAGE: CROSS DISPERSION FP1 ECHELLE FP2 FP3 CROSS DISP OAP1 OAP2 FLD1 OAP3 CAM FP: Focal plane OAP: Off axis parabola FLD: Folder mirror

8 Optical design CRYOSTAT ENTRANCE ECHELLE GRATING FOLDER MIRROR Intermediate focal plane Off axis parabola CALIBRATION GAS CELL CROSS DISPERSION UNIT Off-axis parabola FOCAL PLANE WHEEL. -ADC -IMAGE SLICER -SLIT APERTURES Detector CAMERA (Three Mirrors+ Corrector) U. Laux, E. Sánchez Blanco,S. Gennari, T. Peacocke Slit: Nominal, fixed slit x for 2Kx2K array Conceptual mechanical design 2330mm 1200mm

9 Wide wavelength coverage J H K High stability cryostat Collaboration between Arcetri, IAC and Lisbon

10 Ø 1620mm 2620mm Sizes of optical elements Element Clear aperture (mm) FP1 ~ 2 x 2 OAP1, OAP2 109 ECHELLE 109 x 220 FLD1 ~ 10 x 10 FP2 ~ 2 x 2 OAP3 CROSS DISP DETECTOR (HAWAII-2) 36.8

11 Prisms of ZnSe Ohara GmbH ±1.0 mm ±1.0 mm euros What calibration?

12 Gas cell development Mid-resolution gas cell spectra Collaboration with R. Peale group (UCF)

13 Single vessel e=40 mm (wall thickness) Double vessel e=20 mm (wall thickness)

14 NIR RV Planet Search Space Figure by R. Tata 27 28

15 NAHUAL SENSITIVITY Figure by M.R. Zapatero Osorio e = 0.3 i = 30 o Primary dm5 Mass 0.2 M sol 3 m/s ((3 sigma) in 300 s for K=9 and D = 10 m. D=40m => K=12-14 => L and T dwarfs => lowest mass planets around the lowest mass primaries? NAHUAL connection with ALMA disk fraction 1 H-K K-L log (age/yr) log (age/yr) Hillenbrand (2006) In clusters with known age -> average life time of disk inner disk fraction gradually decreases over 10 Myr from >80% to <10% inner disk half-life 2 3 Myr Wilking et al. 1989; Strom et al. 1989; Haisch et al. 2000, 2001

16 ALMA & NAHUAL complementarity (1 Myr) Martin et al Klein et al Gas DoAr 21 Dust makes up 1% by mass of interstellar gas assumed to be the same in disks 99% of mass is gas, mostly H2 (80%) and He (20%) H2 is difficult to detect no permanent dipole -> no dipole rotational transitions; only weak quadrupole transition in mid-ir that require hundred K or more to excite conflicting reports about detection fluorescent H2 emission Fluorescent in UV H2: (electronic transitions) and near-infrared UV/X-ray excitation (vibrational) has been detected but is difficult to analyze quantitatively Bary et al. (2002)

17 Disk gaps Spitzer SEDs -> transitonal or cold disks with cleared-out zones inner disk edges range from < AU sometimes a low-mass inner disk is present sometimes gas is present in the gap continued accretion across the gap? CoKu Tau/4: D Alessio et al. (2005) Gaps TW 7 mm/ VLA: Hughes et al. (2007) Interferometers can now image these gaps Need to be careful to interpret as evidence for planets: may be due to photoevaporation observations model residuals LkH 850 m/sma: Brown et al. (2008)

18 Evidence for planet formation? Grain growth Gaps TW Hya Planet candidate around TW Hya, but not confirmed in IR Theoretical models take knowledge of disk structure from observations as initial conditions for planet formation...and have testable predictions: gaps, spiral arms,... Setiawan et al. (2008) NAHUAL-ALMA connections IR RV planet searches in T Tauri stars with disk gaps IR spectroscopy of disk accretion diagnostics IR spectral analysis of TTS => improved stellar parameters

19 Summary NAHUAL could be working at GTC in 2013 as visitor instrument, and/or as mid and high-resolution near-infrared spectrograph GTC in years of experience and 1 million euros of development investment as of NAHUAL experience is applicable to other (bigger or smaller) telescopes, such as Calar Alto and the ELTs. A crazy proposal? Highly stable spectrographs (CODEX, ESPRESSO, HARPS, NAHUAL, SIMPLE, etc) require homegeneous high-troughput illumination, small FOV, seeing matched aperture that can be mapped with fibers or image slicers. High-contrast imagers & IFUs require high-quality images over a moderate FOV, diffraction limited performance, AO-assisted. High-resolution spectroscopy & High-resolution imaging have orthogonal requirements for telescope design. Proposal: 1) make first a low-cost spectroscopic ELT first (33 meter?), testbed for even larger ELT, fast-track, spectroscopic science 2) build on the ELT testbed for construction of an imaging ELT with full AO performance, longer-term project

20 Crazy things happen