Multi-IFU spectroscopy on the LBT Andreas Kelz, [email protected] Astrophysikalisches Institut Potsdam...

Multi-IFU spectroscopyon the LBT

Andreas Kelz, [email protected] Institut Potsdam

2nd Gen Science with the LBT workshop, Ringeberg, 18.7.2008

A. Kelz: Multi-IFU Spectroscopy on LBT, Ringberg workshop, 18. July 2008

3D- and fiber-spectroscopy projects at

AIP

PMAS MUSE VIRUS STELLA & 3.5m CA 8m VLT 9m HET 6dF/RAVE


PMAS

www.caha.es/pmas

PMAS: Roth, Kelz, et al., 2005, PASP 117, 620

Lens-array-IFU:256 spectra,

8“ to 16“ FoV, spectrophotometry

options: + nod & shuffle,

+ Fabry-Perot Etalon+ polarimetry

PPak-IFU: Fiberbundle, 382 spectra,

wide FoV:74“ x 64“

+ simul. calibrat.

PPak: Kelz, Verheijen, et al., 2006, PASP, 118, 129

PMAS features 2 IFUsand a spectrograph

corrected from 340-900nm


Science example with the PPak-IFU: the Disk Mass Project

P. I. Marc Verheijen

Right: UGC 463: re-constructed from the PMAS data cube between 450-600 nm, 1.35“/pixel. Left: POSS image for comparison. Note, that

despite the coarse sampling the basic morphology is reconstructed well.

using E3D

Aim: to measure the velocity distributions of face-on spirals to constrain dark matter contribution.


Advantage: Spatial binning

99 x 108 arcsec

HST/WFPC-2

NGC3982

gaining S/N in particular for the fainter outer parts of galaxies by spatial binning of spaxels

in azimuth.Credit: M. Verheijen, Kapteyn Institute, Groningen

PPak-FoV

74 x 65 arcsec


Science example: clusters, gravitational lenses

6 hours integration with PPakLambda: 460-780nm

de-blended to 1“/pixel

3 hrs HST image (re-sampled to seeing conditions)

Sanchez & Cardiel et al 2007

Abell2218


Advantage: multi-plex information

3 dither pointings yielded 993 spectra 455 monochromatic plus various

polychromatic images

Sanchez & Cardiel et al 2007


Science example: large fields – mapping the Orion nebula

Sanchez et al. 2006

Line ratio and abundance maps7.5 arcmin

10600 spaxel (spectra)


Science example: Luminosity Function of Ly galaxies

Peter Schuecker (MPE)Ralf Bender (USM/MPE)Ulrich Hopp (USM/MPE)Ralf Köhler (USM)

Karl Gebhard (UT)Gary Hill (UT)Philipp McQueen (UT)

Matthias Steinmetz (AIP)

Peter Weilbacher (AIP)Joris Gerssen (AIP)

-> Baryon oscillations(HETDEX)


Astronet Infrastructure Roadmap

8.2.3 Ground-based, Small Scale:

Wide-Field, Multiplexed Spectrograph.

There is an extremely strong scientific case for the development of such an instrument which could be placed at one of a number of existing 8-10m class telescopes (see Section 4.3.2). Such a project was therefore given high scientific priority. The term “wide-field” here means a FOV of at least 1.5 degrees (goal 3 degrees) in order to provide simultaneous spectroscopic observations of thousands of objects over a FOV matched to the scientific requirements, comparable to that envisaged for the next generation wide field imagers, e.g. the LSST. The primary science drivers are the determination of the equation of state of Dark Energy, the study of stellar populations over a large fraction of the history of the Universe, and the study of the structure and formation of the Galaxy and Local Group by determining in a quantitative manner the kinematical and chemical signatures of the different stellar components.


IFU capabilities at 8-10m

VLT: VIMOS-IFU, SINFONI, FLAMES-IF (in operation) KMOS, MUSE, SPHERE (2nd Generation)

Gemini: GMOS

Keck: OSIRIS

GTC: FRIDA, SIDE

LBT:

(… but all have relatively small fields, e.g. MUSE has 90,000 spaxels but 1‘ x 1‘ FoV …)


Multi-IFUsN

GC

6946,

LB

C

PPak-styleIFU‘s in dense

configuration


Multi-IFU Spectrograph for LBT-Gregorian

LBT

Gregorian station: usable FoV: 10‘ (evt. up to 24‘ ?) F/15 beam + focal red. to ~F/5

7 deployable IFUs each IFU: - ~ 250-300 fibers- 1/3 fill factor - size of ~1.5 arcmin

total no. of fibers: ~ 1750 - 2100

10‘

60‘‘-90‘‘


Example: Stellar populations

M101 (10‘ x 10‘), each IFU: 90‘‘ x 90‘‘


Example: Galaxies & Mergers

M51 (10‘ x 10‘), each IFU: 90‘‘ x 90‘‘


Example: Galaxy clusters, gravitational lenses, ...

Abell1185 (10‘ x 10‘), each IFU: 90‘‘ x 90‘‘

the deployable IFUs can be set on different targets.

field #1 field #2


VIRUS-IFU: layout

– IFU format: hexagonal packed

– Dense-pack design with 1/3 fill factor

– 3 dither exp. to fill the field– 200-250 fibers / IFU – Fiber core diameters:

200-300 microns – Step-index quartz

broadband multimode fibers

– Mapping from IFU to slit: either row by row or random

VIRUS P.I. G.Hill, McDonald Obs.


VIRUS-IFU input head design

– Small mount design allows ¼ packing fraction – Precision mount with capillary tubing or

precision mask to set matrix (design and manufacture at AIP)

6 mm

11.5 mm


Fiber bundle developments at AIP

Built and under development at AIP: PPak, VIRUS-P1, VIRUS-P2, …, V-Wendelstein


1 fixed central IFU and 8 deployable IFUs using R- or x-y positioners with a densest IFU fill factor of ¼ advantage: relative „simple“ simulataneous positioning, medium-sized units allow industrial replication at affordable prices.

8 positioners with

R-stages (or x-y stages)

IFU placement

VIRUS IFU-Spectrograph Modified replicated integral field

spectrographs (VIRUS-type) – Inexpensive fiber-fed unit IFS – Each with ~250 fibers .– Visible wavelength coverage

VIRUS Prototype

VIRUS design by: P. MacQueen

McDonald Observatory

IFU-Spectrograph placement at LBT

IFUs and positioner at direct Gregorian focal station - less complex than prime focus, - place stages & bundles in AGW-type ring structure

Spectrograph placementa)at Gregorian station but with grav. stable mount (issues: size, weight, space) b)on the ground (issues: fiber length and effects due to bending, location) c)use MODS (but off-telescope)

© McDonald Observatory

© McDonald Observatory


Further options …

- use extended FoV (up to 24‘ ?) at Gregorian focus with/without a corrector lens (vignetting, PSF) ?

- option to connect IFU fiber bundles to stationary MODS on the ground (fiber length & numbers of fibers, calibration, ADC) ?

- IFUs at prime foci (evt. at f/4.5 trapped Cass. Focus) + long fiber lengths (plate scale, space, corrector,… ?)

- use of photonic technologies, such as photonic crystal fibers, fiber bragg gratings, arrayed waveguide gratings, miniaturized spectrographs, …

- innovation center for fiber-based spectroscopy (innoFSPEC) and Astrophotonic related R&D at AIP.


About innoFSPECThe Potsdam Center for Fiber-based Spectroscopy and Sensing innoFSPEC is a joint initiative of the Astrophysical Institute Potsdam (AIP) and the University of Potsdam, Dept. Physical Chemistry & Interdisciplinary Photonics Center (UPPC), whose goal is to create a national center of excellence.

The primary research fields of innoFSPEC are- Fiber-coupled multichannel spectroscopy (AWG, PCF, FBG, replicable-miniaturized MCS, …) - Optical fiber-based sensing

innoFSPEC requested funding for- 2 research groups with 2 associated-professorships - 6 postdocs and 6 PhD student positions - 1 center manager and 1referent assistant - funding for personal, infrastructure, equipment, travel, etc… - in total: 7.7 M€ granted for 5 years (2008-in total: 7.7 M€ granted for 5 years (2008-20142014) )

innoFSPEC excellence centerinnoFSPEC excellence center

www.innofspec-potsdam.de

Multi-IFU spectroscopy on the LBT Andreas Kelz, [email protected] Astrophysikalisches Institut Potsdam...

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