Line Detection Rates for Next Generation IR/Submm Spectroscopic Surveys Eric J. Murphy BLISS/X-Spec Science teams

Meet Dylan

Why mid-/far-IR Spectroscopy: BLISS? Many bright atomic fine-structure + access to H 2 lines and PAH features Many bright atomic fine-structure + access to H 2 lines and PAH features 1Cosmic Star Formation History  SFR, gas density, etc. 2Cosmic Rise of Heavy Elements  PAH emission at z ~6 3Black Hole Birth  Extreme species e.g., [NeV] and high-J CO lines 4Gas in Forming Planetary Systems  Gas cools through FIR atomic O and C transitions -- gas-disk lifetimes BLISS band at z=2 BLISS band at z=4 Circinus Galaxy ISO SWS+LWS Egami et al 2006, Spitzer IRS Detectable at z~8-10 with BLISS!

Why Submm Spectroscopy: X-Spec Many bright atomic fine- structure and molecular rotational transitions detectable. Many bright atomic fine- structure and molecular rotational transitions detectable. Spectroscopic redshifts and interstellar gas conditions from galaxies in the early universe (i.e., z > 6) Spectroscopic redshifts and interstellar gas conditions from galaxies in the early universe (i.e., z > 6) e.g., z=6.42 Walter et al. 2009). e.g., z=6.42 Walter et al. 2009). Much faster (~30x) than ALMA for survey work! Much faster (~30x) than ALMA for survey work! Z-spec Spectra from Bradford+ (2011/2010) z=2.56

BLISS/SPICA Specs. ParameterGoalRequirementScientific / Technical Driver Primary Aperture 3.15 m Telescope Temperature5.5 K ~ x10,000 lower background than Herschel (T ~ 80 K) Line sensitivity (3 , 1h) 1 x W m -2 2 x W m - 2 Observing galaxies from the first billion years of the Universe to the present day. Observing galaxies from the first billion years of the Universe to the present day. Spectral resolving power (  ) Avoiding line confusion with multiple sources along the line of sight. Spectral coverage 35 – 433 μm Simultaneously covered in 6 bands Completely fill spectral gap between JWST / SPICA mid-IR & ALMA. Number of beams2 (source + reference) Redundancy against a single detector failure & improved sensitivity/sampling. Detector sensitivity (NEP)5x W/Hz -1/2 1x W/Hz - 1/2 Supports astronomical sensitivity requirement, close to natural photon background. Instrument temperature50 mK60 mKSupports detector sensitivity. SubsystemApproachHeritage TES bolometer array systemJPL dual TES w/ Ti, AlBICEP2, SPIDER (balloon) Low-NEP TES bolometer60mK MoCu bilayer on mesh absorberBLISS development program Detector cold readoutNIST time-domain SQUID MUXBICEP2, SPIDER, SCUBA2, ACT, etc Short-wavelength spectrometerCross-dispersed echelle gratingSpitzer IRS (flight) Long-wavelength spectrometerWaFIRS waveguide gratingZ-Spec Instrument cooler50 mK adiabatic demagnetization (ADR)Z-Spec, SPIFI Chopping mirrorLow-dissipation 4K mechanismHerschel HIFI

First Light Instrument for CCAT First Light Instrument for CCAT Primary Mirror: 25m Primary Mirror: 25m chopping Secondary? B1: 575 – 945 μ m B2: 965 – 1535 μ m chopping Secondary? B1: 575 – 945 μ m B2: 965 – 1535 μ m MDLF (3 σ, 1hr): 0.72 – 7.2 x W m -2 MDLF (3 σ, 1hr): 0.72 – 7.2 x W m -2 SuperSpec chip with MKIDs SuperSpec chip with MKIDs Simpler readout architecture than TES bolometers Simpler readout architecture than TES bolometers detectors per wire vs detectors per wire vs Two potential implementations: Two potential implementations: Direct Imaging Spectrometer Direct Imaging Spectrometer Steered Beam Multi-object Spectrometer Steered Beam Multi-object Spectrometer X-Spec/CCAT Specs.

BLISS/X-Spec Sensitivities Put into Context Matt Bradford

Is confusion going to be an issue? Constructing Line Count Models Galaxy Number Count Models: N ( z, L IR ) Galaxy Number Count Models: N ( z, L IR ) E.g., Chary & Pope (2012) E.g., Chary & Pope (2012) Uses the deepest 24 μ m data & Spec- z ’s from GOODS Uses the deepest 24 μ m data & Spec- z ’s from GOODS Constrained by the Cosmic IR Background Constrained by the Cosmic IR Background Consistent with Herschel observations Consistent with Herschel observations Does not take clustering into account Does not take clustering into account Empirical Line Prescriptions (31 lines included) Empirical Line Prescriptions (31 lines included) 15 mid-/far-IR lines: Spinoglio et al. (2012) 15 mid-/far-IR lines: Spinoglio et al. (2012) 16 CO & other submm line: Visbal & Loeb (2010) 16 CO & other submm line: Visbal & Loeb (2010)

Integral Line Counts: BLISS/SPICA  More lines at longer wavelengths  Naturally, since beam increases w/ λ  Also, more species available (8 to 16 between 50 and 350 μ m) 50 and 350 μ m)  At 250 μ m, one line per 75 beams detected (5 σ ) with > 1.5 x W m -2 (5 σ ) with > 1.5 x W m -2 1 hr

Integral Line Counts: X-Spec/CCAT  More lines at longer wavelengths  Naturally, since beam increases w/ λ  Number of available species ~17 at all λ  At 1.3mm, 70 x 1hr pointings (300 beams/pt) to detect a single line (5 σ ) with >1.5 x W m -2 detect a single line (5 σ ) with >1.5 x W m -2 1 hr 70 hr

So, even with BLISS, confusion is not an issue… But can we extract lines from spectra? Assuming two off nod positions Intrinsic Source Spectrum Blank Field Spectrum 10 Examples  Confused Spectra  Monte-Carlo number counts between NGC520, Mrk231, and Arp220  Mock Observation of NGC520 at z =4 scaled to L IR 2x10 12 L 

Findings & Remaining Issues BLISS: BLISS: Line Confusion does not seem to be an issue Line Confusion does not seem to be an issue How well can identify & recover line fluxes in spectra? How well can identify & recover line fluxes in spectra? Quantify how the continuum shapes of sources are affected by intervening sources (needed for M d, T d, L d ). Quantify how the continuum shapes of sources are affected by intervening sources (needed for M d, T d, L d ). Is R =400 too course spectral resolution? Is R =400 too course spectral resolution? X-Spec X-Spec Many pointings to measure1 line even with 300 beams Many pointings to measure1 line even with 300 beams Steerable system or a integral field unit? Steerable system or a integral field unit?

BLISS Specs. ParameterGoalRequirementScientific / Technical Driver Line sensitivity (3 , 1h) 1 x W m -2 2 x W m -2 Observing galaxies from the first billion years of the Universe to the present day. Spectral resolving power (  ) Avoiding line confusion with multiple sources along the line of sight. Spectral coverage microns in 6 bands Completely fill spectral gap between JWST / SPICA mid-IR & ALMA. Number of beams2 (source + reference) Dual beam provides redundancy against a single detector failure producing a hole in spectral coverage, and improved sensitivity and sampling. Detector format Full coverage across the BLISS band in two fields. Detector sensitivity5x W/Hz -1/2 1x W/Hz -1/2 Supports astronomical sensitivity requirement, close to natural photon background. Instrument temperature50 mK60 mKSupports detector sensitivity. SubsystemApproachHeritageTRL TES bolometer array systemJPL dual TES w/ Ti, AlBICEP2, SPIDER (balloon)6 Low-NEP TES bolometer60mK MoCu bilayer on mesh absorberBLISS development program3-4 Detector cold readoutNIST time-domain SQUID MUXBICEP2, SPIDER, SCUBA2, ACT, etc6 Warm electronicsMulti-channel electronics (MCE)….same….6 Short-wavelength spectrometerCross-dispersed echelle gratingSpitzer IRS (flight)7 Long-wavelength spectrometerWaFIRS waveguide gratingZ-Spec6 Instrument cooler 50 mK adiabatic demagnetization (ADR) Z-Spec, SPIFI6 Intercept cooler300 mK continuous He sorptionHerschel SPIRE7 Chopping mirrorLow-dissipation 4K mechanismHerschel HIFI

X-Spec/CCAT Specs.