Wide Field Integral Spectroscopy with PrISM
Jeff Rich GalPath
Barry Madore, Mark Seibert, Vicky Scowcroft, Laura Sturch Massive IFU Surveys: a data cube for every galaxy
-Surveys collecting Integral Field Spectra (IFS) for >10,000 galaxies
-ATLAS3D, CALIFA, SAMI, MaNGA, smaller surveys
-IFS data allows us to examine transformative processes in detail The WiFeS GOALS Survey: IFS of 40 Merging galaxies
Rich et al. 2015 R-band Digitized Sky Survey images WiFeS Field of View overlaid The WiFeS GOALS Survey
370-700 nm, R~7000 25”x38” FOV
40 individual galaxies, from beginning to end of merger sequence
Redshift of 0.009 - 0.049 -200-900 parsecs/pix (650-3000 lyr/pix) Measuring ISM Properties
-Low spatial resolution, relatively high spectral resolution
-Resolve individual velocity components in single LOS, compare with line ratios
-Separate HII region, AGN, Shocks, measure O/H, kinematics
Rich et al. 2011, ApJ, 734, 87 Measuring ISM Properties Nuclear vs. Resolved Spectroscopy
IFS data reveal that ISM is ionized by radiative shocks
=>Single fiber/slit data can misidentify AGN
[O III]/Hb
x
NGC 3256 Rich et al. 2011, 2014 WiFeS GOALS Survey Using Shocks to Trace Gas Flows Caused by Merger Process Isolated (3) Widely Separated ‘a’ (4)
Closely Interacting ‘b’ (9) Coalesced ‘cde’ (3) Using Shocks to Trace Gas Flows Caused by Merger Process
-Young stars dominate emission Young Stars before merger, Shocks increasingly contribute to emission as mergers Shocks progress -Shocks trace increasing inflows Turbulent Star Formation and outflows during merger -Presence of Shocks can affect typical measurements made with emission lines (O/H, SFR, etc.) Using Metallicity to Trace Gas Flows
Spectra from data cubes can be ESO 138-G27 used to measure metallicity via strong-emission line methods
Undisturbed spiral galaxies show a gradient in [O/H], decreasing from the center to the outskirts
Gas flows in merger are predicted to disrupt this gradient [O/H] Using Metallicity to Trace Gas Flows
Before Merger: Steep Metallicity Gradient
ESO 138-G27 Oxygen [O/H] Oxygen
Radial Distance Rich et al. 2012 Using Oxygen to Trace Gas Flows
During/After Merger: No Metallicity Gradient
IC 1623 Oxygen [O/H] Oxygen
Radial Distance Rich et al. 2012 Resolution v. O/H Gradient
-Spatial resolution of data can impact measurements
-Poor resolution results in underprediction of metallicity gradient
Yuan, Rich & Kewley 2013 Resolution v. Dynamics
Kinemetry derived from IFS can be used to identify merger activity (Krajnovic+06, Shapiro+08, Bellocchi+12)
Shapiro et al. 2008 Rich et al. 2011, ApJ, 734, 87 Resolution v. Dynamics
-Spatial resolution can affect Merger/Disk kinematic classifications
-Kinematics from low-res IFU data cannot constrain merger fraction of z~1-3 galaxies
Hung et al. 2015 High(er) Spatial Resolution? Nearby galaxies yield intrinsically high(er) resolution ...but require significantly more time to observe
NGC NGC 1365 3256 Progressive Integrated Stepping Method (PrISM)
Integral Wide-Field Narrow Band Imaging Stacked Integral Progressive Integral Spectrsocopy (e.g Fabry-Pérot) Field Units Step Method (PrISM)
y (arc-minutes)
wavelength x (arc-minutes)
Spatially Resolved Galaxy IFS: Simple Execution: star formation modern telescope control systems star formation histories desktop computing power chemical evolution cheap disk storage separated by morphological components ~ $0 SLS/PrISM Concerns
INEFFICIENT true for small objects true for faint objects use for large bright objects
VARIABLE SKY true always ultra-long slit allows for simultaneous sky for each exposure if diameter < slit. PrISM Specifications @LCO du Pont
Table 1. PrISM Specifications
Field of view (slit) 18’ 1.65” (0.5 arcminute2) ⇥ 1 Spectral resolution R=800 (375 km s FWHM) Spaxel size 1.65” 0.484” (native) / 1.65” 1.65” (binned) ⇥ ⇥ Spatial resolution 2 – 177 pc (48 pc median) Spectral range 3650 – 9000 A˚ a 17 1 2 1 Flux limit (5000A)˚ 4 10 erg s cm A˚ per resolution element ⇥ 33.4 µJy per resolution element µ = 21.1 AB mag / arcsec2 S/N=3, 600 sec., 1.652 arcsec spaxel Telescope 2.5m f/7.5 du Pont telescope, Las Campanas, Chile Camera/Detector Wide Field reimaging CCD (WFCCD) 25 arcminute diameter field WF4K 4064 4064 CCD ⇥ Note. — (a) Spatial binning will provide high S/N measurements far below this limit. ~72 arcsec aperture Typhoon vs SDSS Nucleus of UGC1382 ~7 sqr−arsec aper.
/A] 250 2 200 SDSS 2700 sec. Test Case: Typhoon 600 sec. 150 Typhoon S/N erg/s/cm
17 100 − 50 0 recreating SDSS flux [10 4000 5000 6000 7000 8000 wavelength [A]
/A] 200 2 150
100 erg/s/cm 17 − PrISM 600sec 50 0 flux [10 3800 4000 4200 4400 4600 SDSS 2700sec wavelength [A]
/A] 250 2 200
150 erg/s/cm 17 − nucleus of UGC1382 100 50 flux [10 4600 4800 5000 5200 5400 5600 distance=80 Mpc wavelength [A]
/A] 250 2
200 erg/s/cm
22 steps 17 − 150
100 0.6’ x 8.9’ flux [10 5600 5800 6000 6200 6400 6600 wavelength [A]
/A] 250 2
200 erg/s/cm 17 1.65”x1.65” − 150 100 flux [10 6600 6800 7000 7200 7400 7600 binned pixel scale wavelength [A]
/A] 250 2
200 erg/s/cm 17
− 150
100 flux [10 7600 7800 8000 8200 8400 wavelength [A] M83 / NGC5236 Raw Data 5 Nights
179 Spectra 5’ x 18’ Reduction is like long slit data but with 2D distortion corrections over entire FOV BVR+Hα M83 / NGC5236
5 Nights
179 Spectra 5’ x 18’ Reduction is like long slit data but with 2D distortion corrections over entire FOV ~9x108 voxels @native res. ~3x108 voxels @binned res. relative flux 4000 4500 5000 wavelength [ 5500 Å 6000 ] 6500 7000 5 arc-minutes
12 arc-minutes SINGGS NB Imaging PrISM Extraction λ=6568Å Δ 30Å λ=6568Å Δ 30Å 10 10
5 5
0 0
-5 -5 Meurer et al. 2006 (binned at 1.65”)
-10 -10
-2 0 2 kpc -2 0 2 kpc
-0.6 0.3 1.2 2.1 3.0 log erg/s/cm 2/Å/1e-17 H [OIII] H [NII] [SII] 6717Å [SII] 6731Å