Presentation on theme: "The HARMONI integral field spectrograph Niranjan Thatte University of Oxford A Work-Horse Instrument for the E-ELT."— Presentation transcript:
the HARMONI integral field spectrograph Niranjan Thatte University of Oxford A Work-Horse Instrument for the E-ELT
What do Giants Eat? Fe-Fi-Fo-Fum, I smell the blood of an Englishman, May he be alive, or may he be dead… I’ll grind his bones to make my bread
HARMONI at the E-ELT
HARMONI Consortium Matthias Tecza 1, Fraser Clarke 1, Roger L. Davies 1, Alban Remillieux 2, Roland Bacon 2, David Lunney 3, Santiago Arribas 4, Evencio Mediavilla 5, Fernando Gago 6, Naidu Bezawada 3, Pierre Ferruit 2, Ana Fragoso 5, David Freeman 7, Javier Fuentes 5, Thierry Fusco 18, Angus Gallie 3, Adolfo Garcia 10, Timothy Goodsall 8, Felix Gracia 5,Aurelien Jarno 2, Johan Kosmalski 2, James Lynn 1, Stewart McLay 3, David Montgomery 3, Arlette Pecontal 2, Hermine Schnetler 3, Harry Smith 1, Dario Sosa 5, Giuseppina Battaglia 6, Neil Bowles 1, Luis Colina 4, Eric Emsellem 6, Ana Garcia- Perez 13, Szymon Gladysz 6, Isobel Hook 1, Patrick Irwin 1, Matt Jarvis 13, Robert Kennicutt 19, Andrew Levan 17, Andy Longmore 3, John Magorrian 1, Mark McCaughrean 16, Livia Origlia 11, Rafael Rebolo 5, Dimitra Rigopoulou 1, Sean Ryan 13, Mark Swinbank 15, Nial Tanvir 14, Eline Tolstoy 12, Aprajita Verma 1
A Single Field Wide Band Spectrograph A near infrared integral field spectrograph covering the 0.8 − 2.4 μm wavelength range, with simultaneous coverage of at least one band at a time. R~4000 to work between the OH lines. Range of spatial resolutions: from diffraction limited to seeing Possible extension to visible wavelengths and higher spectral resolution (both now included!) High throughput (>35%), low thermal background (optimized for K band operation), low scattered light
Design Drivers Spatially resolved detailed studies of astrophysical sources – physical, chemical, dynamical & kinematics; also ultra-sensitive observations of point sources. Easy to operate and calibrate Feasibility for 1 st light instrument => simple, reliable, based on proven concepts, can be built with today’s technology. Large amount of expertise in consortium Workhorse instrument – wide range of science programs, all AO modes, range of spatial & spectral resolutions
For extended sources & optimal FoV For optimal sensitivity (faint targets) Best combination of sensitivity and spatial resolution 40 mas 20 mas10 mas Highest spatial resolution (diffraction limited) 4 mas 7 7 f f 2.5” × 5” 5” × 10” 1.25” × 2.5” 0.5” × 1.0” 128 × 256 spaxels at all scales
Wavelength Ranges & Resolving Powers Band min [µm] max [µm] [Å/pixel] R H+K I+z+J V+R K H J I+z R V K high H high J high z R high V high
Scientific motivation At the fine scale of E-ELT + HARMONI working in the diffraction limit there is enormous value in being able to reconstruct where, in a complex image, a spectrum arises. Using AO in the infrared conditions change rapidly so that a simultaneous recording of all positions and wavelengths removes ambiguities. At high z there are many more morphologically complex, low mass objects. Fine angular resolution and high spectral resolution are needed. IFU records PSF from observations (if FoV contains a point source e.g. quasar BLR).
Stellar Populations: star formation history, chemical & dynamical evolution. Aim to use abundance patterns in RGB & MS stars to unravel star formation history of each galactic component. This work is currently only feasible in MW & MC. EELT+HARMONI will probe local groups (eg. Centaurus & Leo groups) and at the limit reach the Fornax and Virgo clusters. This takes stellar population studies into a completely unexplored realm. Simulations show that metallicities (±0.3) & velocities (±20km/s) can be measured 1mag fainter than the tip of the RGB in CenA in 1hr at R=9000. In M87 20 hrs a sample of ~30 stars Challenge: the main metallicity indicators are in the visible. Thus this work does not take full advantage of the AO. Can infrared diagnostics be identified that will give reliable metallicities for RGB stars? Requires: R= 9000 & 20,000 spectra, 20mas & .
5mas per pixel input10 mas HARMONI scale20 mas HARMONI scale40 mas HARMONI scale100 mas scale on VLT
High-z Ultra-luminous IR Galaxies o Survey 50 Spitzer candidate ULIRGs 1 4000 spectra, spaxels . H in z=2 ULIRG
The Physics of High Redshift Galaxies z=2-5 Requires : R > 4,000 – 20,000 J+H & H+K simultaneously mas spaxels FOV 0.5 x 1.0”; 5 x 10”. Aim: measure the size, velocity & luminosity distribution of HII regions –HII regions as tracers of SFH, mass & mergers –Reddening free estimate of star formation rate –Measure abundances for individual SF regions –Explore HII kinematics as diagnostic of disk settling.
High Contrast Science – Characterising Exo-solar Planets Requires : R > 4,000 – 20,000 I+z+J, H+K simultaneously. 4 mas spaxels, FOV 0.5 x 1.0”; SCAO. Aim: follow-up spectroscopy of candidate exo-solar planets seen by VLT –Spectral lines provide measure of surface gravity –Combine with other techniques to get density, temperature and luminosity. –Clues to atmospheric composition – constrain models
Complimentarity with ALMA ALMA will detect cold gas at similar spatial resolution. Many applications require physical properties of both cold gas (ALMA) and stars/warm gas (E-ELT + HARMONI) to advance astrophysics: How is cold gas converted to stars to make disks and bulges? What fraction of star formation occurs dues to mergers compared to in-situ processes? What mechanisms drive star formation in high-z galaxies? How do the masses of black holes grow? How do they impact galaxy evolution? How does the generation of heavy elements evolve? Case study: ALMA will measure CO content of Milky Way-like progenitors at z>2. HARMONI will map distribution, strength & velocities of emission line gas. SFR + mass of cold gas reservoir star formation timescale duty cycle Gas/star & gas/dynamical mass fractions build galaxy components Determine mode of star formation as f(z), environment and galaxy type. What is the dominant mode of star formation at high-z? through GMCs (as in the MW) or starburst (ULIRGs)?
JWST is ~7 smaller than E-ELT but will operate in a low background environment at L2. Even where they are most closely matched NIRSpec and HARMONI have different capabilities. For example: Spectral resolution. Highest R for NIRSpec R=2700 (in practice ). For HARMONI R lower than 4000 will lead to contamination by telluric lines. Different spaxel scales => different angular resolution regimes Extraction apertures Characterise the two instruments by balancing low background against increased flux and resolution to determine at what wavelength E-ELT + HARMONI is instrument of choice. Compare of the required exposure time for several “standard” cases. page 16 HARMONI vs. JWST NIRSpec IFU
page 17 HARMONI vs. JWST NIRSpec o At J & H E-ELT + HARMONI even in natural seeing HARMONI is 10 faster. o Using LTAO and for extended sources the advantage rise to 100. o At K-band the advantage is retained with LTAO. With GLAO & natural seeing the two facilities are comparable, HARMONI wins at the blue end of K. o Note that both NIRSpec and HARMONI offer other, less comparable capabilites where they have a greater advantage.
Field of View: shape High precision sky subtraction is essential nodding-on-IFU Half integration time cf. offset sky measurements. 2:1 aspect ratio for FoV
Field of View: size & sampling Variable sky & PSF advantage to avoid mosaicing Typical single objects at z>1 128 x 20mas for short dimension of IFU Large objects (QSO hosts) or diffuse emission & stellar pops studies largest possible FoV Linear size of spaxel (pc) Linear size of FoV (kpc)
Different Flavours of AO SCAO GLAOLTAO Or even degraded GLAO (NGS only) !!!
Sensitivity 20 mas spaxels provide best sensitivity for point sources 40 mas spaxels best for extended sources
Challenges Large instrument size and mass makes handling difficult HARMONI Integration Laboratory HARMONI Cryostat PI
Challenges Large instrument size and mass makes handling difficult. Managing large consortia requires professional approach, implies larger management overhead. Time is precious – efficient operations, long MTBF, simple user interface, preparation software. Track every item through design, manufacturing, assembly, integration and testing – take nothing for granted
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