the HARMONI
integral field spectrograph
A Work-Horse
Instrument for the
E-ELT
Niranjan Thatte
University of Oxford
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 Tecza1, Fraser Clarke1, Roger L. Davies1, Alban Remillieux2,
Roland Bacon2, David Lunney3, Santiago Arribas4, Evencio Mediavilla5,
Fernando Gago6, Naidu Bezawada3, Pierre Ferruit2, Ana Fragoso5, David
Freeman7, Javier Fuentes5, Thierry Fusco18, Angus Gallie3, Adolfo
Garcia10, Timothy Goodsall8, Felix Gracia5,Aurelien Jarno2, Johan
Kosmalski2, James Lynn1, Stewart McLay3, David Montgomery3, Arlette
Pecontal2, Hermine Schnetler3, Harry Smith1, Dario Sosa5, Giuseppina
Battaglia6, Neil Bowles1, Luis Colina4, Eric Emsellem6, Ana GarciaPerez13, Szymon Gladysz6, Isobel Hook1, Patrick Irwin1, Matt Jarvis13,
Robert Kennicutt19, Andrew Levan17, Andy Longmore3, John Magorrian1,
Mark McCaughrean16, Livia Origlia11, Rafael Rebolo5, Dimitra
Rigopoulou1, Sean Ryan13, Mark Swinbank15, Nial Tanvir14, Eline
Tolstoy12, Aprajita Verma1
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 1st 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
20 mas
10 mas
4 mas
40 mas
For extended
sources &
optimal FoV
For optimal
sensitivity
(faint targets)
Best
combination
of sensitivity
and spatial
resolution
5” × 10”
2.5” × 5”
Highest
spatial
resolution
(diffraction
limited)
128 × 256
spaxels at
all scales
1.25” × 2.5”
f7
0.5” × 1.0”
Wavelength Ranges &
Resolving Powers
Band
min[µm]
max[µm]
 [Å/pixel]
R
H+K
1.450
2.450
2.500
3900
I+z+J
0.800
1.360
1.400
3857
V+R
0.470
0.810
0.850
3765
K
1.950
2.450
1.250
8800
H
1.460
1.830
0.925
8892
J
1.080
1.360
0.700
8714
I+z
0.820
1.030
0.525
8809
R
0.630
0.790
0.400
8875
V
0.500
0.630
0.325
8692
K high
2.090
2.320
0.575
19174
H high
1.545
1.715
0.425
19176
J high
1.170
1.290
0.300
20500
z
0.820
0.910
0.225
19222
R high
0.610
0.680
0.175
18428
V high
0.530
0.590
0.150
18666
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 spaxels @  0.6 - 1.0 & 1.0 - 2.5.
10
20
40
100
5mas
mas
mas
per
HARMONI
scale
pixel on
input
scale
VLT
High-z Ultra-luminous IR Galaxies
o Survey 50 Spitzer candidate
ULIRGs 1<z<2.5
H in z=2 ULIRG
o Detect & characterise nuclear
disks & rings
o Measure shocks, winds,
interaction with IGM
o Measure dynamical masses
o Distribution of dust
o Modes of star formation
o
o Measure rotation, masses, dust
content, stellar pops & FP
Requires: diffraction limited R > 4000 spectra,
spaxels 5-40mas. @  0.5 - 2.5.
The Physics of High Redshift Galaxies z=2-5
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.
Requires : R > 4,000 – 20,000 spectra
@  J+H & H+K simultaneously.
4 - 40mas spaxels FOV 0.5 x 1.0”; 5 x 10”.
High Contrast Science – Characterising
Exo-solar Planets
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
Requires : R > 4,000 – 20,000 spectra @ I+z+J, H+K
simultaneously. 4 mas spaxels, FOV 0.5 x 1.0”; SCAO.
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)?
HARMONI vs. JWST NIRSpec IFU
 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
2300-2500). 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
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.
page 17
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
Linear size of FoV (kpc)
Linear size of spaxel (pc)
 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
Different Flavours of AO
SCAO
GLAO
LTAO
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
HARMONI
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
HARMONI
More Information
• Please visit our premier site
We aim to match every PI with his/her
observational program!
http://astroweb1.physics.ox.ac.uk/instr/HARMONI/
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