Instrumentation for 2D Spectroscopy Suresh Sivanandam Assistant Professor Department of Astronomy and Astrophysics Dunlap Institute University of Toronto KIAA-PKU Astrophysics Forum
Focus of Our Research Lab Primary Scientific Focus: Study the formation and evolution of galaxies. Primary Instrumentation Focus: Require high-throughput, multiplexed spectroscopy Develop moderate resolution imaging spectrographs. Develop novel adaptive optics technologies to improve performance of spectroscopic observations of galaxies. Develop technologies that will increase sensitivity of spectrographs.
Wide-Field Imaging (Integral-Field) Spectroscopy
Integral-Field Spectroscopy Credit: M. Westmoquette Require a method to reformat the telescope field into the spectrograph Individual lenslets and fibres to not preserve spatial information Individual slices do preserve spatial information in one direction
Age of Wide Integral Field Spectroscopy Spatially Resolved Kinematics SAURON ATLAS 3D Spatially Resolved Stellar Populations Cappellari et al. (2011) Peletier et al. (2007)
The Need for Integral Field Spectroscopy SAURON Galaxies Emsellem et al. (2007)
Age of Wide Integral Field Spectroscopy Light Bucket Observations VIRUS-P M87 Kinematics out to ~5 re! Murphy et al. (2011)
Age of Large Scale IFS Surveys Visible Several wide integral field spectroscopic surveys Focus mainly on nearby galaxies SAURON (Ngal = 72) ATLAS 3D (Ngal = 260) CALIFA (Ngal ~ 600) SAMI (Ongoing, Ngal ~ 3000) MaNGA (Ongoing, Ngal ~10000) Increasing utility of 2-4 meter class telescopes Infrared Several narrow integral field spectroscopic surveys Focus on distant galaxies (z~1-4) or centres of nearby galaxies SINS (Ngal = 60) KMOS KMOS 3D (Ngal = 600) KROSS (Ngal = 1000) Require large aperture 8-10 meter class telescopes
WIFIS: Wide Integral Field Infrared Instrument Parameters Field of View 50 x 20 Spatial Sampling Spectrograph 1.1 /slice Telescope UAz Bok 2.3-meter (90 ) Detector PI: D.-S. Moon, Project/Instrument Scientist: S. Sivanandam Partners: U. Arizona, U. Florida, KASI 2Kx2K 1.7 μm-cutoff HAWAII-2RG Modes 0.9-1.35 μm 1.5-1.7 μm * Spectral 3,000 2,200 Resolution * Reduced sensitivity Adaptable to different telescopes Commissioning early next year 1.5-m CAD Model of WIFIS
Comparison of Fields of View of IR IFSes Z Gemini NIFS/ 1x KMOS Keck OSIRIS VLT SINFONI Palomar PIFS WIFIS SAURON Visible IFS, Infrared IFS
Figure of Merit: Etendue (ηaω) 1/3 PPAK (CALIFA) ~ SAURON ~ MaNGA Near-infrared IFS Comparison
Integral Field Unit (FISICA) Imager slicer type IFU Advanced Slicer Design (Content 1998) Diamond-turned Optics Transforms rectangular field to virtual long slit 22 slices (18 are used in WIFIS) Toronto Lab Test Image of Pseudo-slit Slicer IFU developed by University of Florida IFU Credit: Nick Raines Eikenberry et al. (2004)
Optical Layout Acquisition/ Guider Camera COLD Infrared Detector Calibration System WARM
IR laser slit image
Stellar Populations in the INfrared Survey (SPINS) Study Stellar Populations and their Kinematics in Nearby Galaxies through IR Integral Field Spectroscopy AGB Primary Scientific Questions: Does the Initial Mass Function (IMF) vary with galaxy properties? HB MSTO RGB Are thermally pulsing AGB (TP-AGB) stars a significant contributor to stellar light in the infrared? MS Can we distinguish pseudo bulges from classical bulges to better construct the MBH- MBulge relationship? HR Diagram of M55 12 Gyr old Globular Cluster - Stellar astrophysicist s view (Credit: Mochejska & Kaluzny)
Sample ~ 100 nearby elliptical galaxies and spirals Broad range of stellar mass, morphological types Existing optical wide integral field data NGC1349 S0 Galaxy Preferred Parent Sample: CALIFA Good match of angular Hβ extent and spatial resolution Large sample of nearby (0.005 < z < 0.03) Hαgalaxies NaD TiO Covers the entire Hubble sequence Mgb Public data g-band releases 200 galaxies now available CaII Future H+K plan: MaNGA galaxies SDSS Image CALIFA Continuum Image CALIFA FOV WIFIS FOV Generated from spectral cube Complement optical large-field IFS surveys
Other WIFIS Scientific Programs Extragalactic: High Mass Star Formation Merger Dynamics and Star Formation Population Gradients in Spirals Galactic: Nucleosynthesis in Supernovae Accretion of Young Stellar Objects Galactic Star Forming Regions [FeII] 1.64 μm image of Cas A (Koo et al.) WIFIS pointings overlaid
Gemini Infrared Multi-Object Spectrograph (GIRMOS) A TMT Pathfinder Instrument Leads: Suresh Sivanandam (PI) and Scott Chapman Partner Institutions: Toronto, Dalhousie, UBC, UVic, Laval, Saint Mary s, UManitoba, York U, NRC-Herzberg, Tohoku U, LAM
GIRMOS - MOAO-fed deployable multi-object IFS Proposed TMT IRMOS pathfinder instrument: Builds on Canadian heritage in multi-object adaptive optics (MOAO). RAVEN project demonstrated the feasibility of MOAO on 8-meter class telescopes (Subaru). Gemini (8.1-meter) scientific instrument with four deployable AO-fed IFUs. Large multiplex advantage compared to other single object AO-fed IFUs. Replicable spectrographs for additional arms (seeking additional partners). VLT SINS survey
GIRMOS - Instrument Parameters and Sensitivity Parameter Requirement Parameter Requirement Telescope Feed Instrument Parameters Gemini-South 8.1-meter MCAO f/33 beam Individual IFU Fieldof-view (arcsecs) 0.75x0.75 1.5x1.5 3.0x3.0 6.0x6.0 (Combined) Wavelength Range 1.1-2.4 µm (J, H, K-bands) Spatial Sampling (mas) 25x25 50x50 100x100 100x100 (Combined) Field-ofregard 2 arcminute diameter patrol field Spectral Resolution R ~3000-6000 Number of IFUs 4 with possibility for more Detector 2Kx2K HAWAII-2RG for every two spectral channels Wide range of scientific programs: Distant galaxy formation and evolution, Local galaxy stellar populations, Near-field cosmology, star formation within the Milky Way, etc. Crucial for detailed JWST follow-up. Expect to carry out large survey program thanks to multiplex advantage. 0.05 mode, R~3000
Thoughts on IFS Instrumentation for LOT Need for wide-field optical IFS (Yong Shi) Instrument parameters: 20 x20 FOV (0.5 /slice) Seeing-limited R~5,000 Wavelength coverage: 0.35-1.0 μm Broad Range of Scientific Programs: Excellent for low surface brightness line emission from high-z sources: Cosmic Web (Intergalactic medium emission) Lyα Emitters Excellent for capturing the stellar population and kinematics of local galaxies: Structure of Galaxies (Baryon and dark matter mass profiles) Formation history of galaxies (IMF, SFH) Current State-of-the-art: VLT s MUSE
VLT MUSE Bacon et al. (2004) Recently commissioned on the 8-meter VLT telescope 24 IFSes that are tiled together to obtain a 1 x1 field-of-view IFS with largest field on 8-10-meter telescope right now Cost: ~30M USD Credit: ESO Ram-pressure Stripped Galaxy
Keck Cosmic Web Imager (KCWI) Morrissey et al. (2014) Relatively wide-field Wide band-pass (two channel design) Variable spectral resolution Nod-and-shuffle for very good sky subtraction. KCWI-Blue commissioning soon Cost: <10M USD
Summary Integral-field spectrographs have broad scientific applications in astronomy. Slicer-based IFSes are well-suited for high throughput and low surface brightness imaging spectroscopy. LOT should consider a wide-field optical IFS as part of its instrumentation suite. Aligned with quite a few scientific programs discussed yesterday. Interested in collaborating on science and instrument development.
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