1 AUI Cooperative Agreement — NSF Panel Review August 25 – 28, 2008 National Radio Astronomy Observatory Science enabled by NRAO facilities into the next decade Chris Carilli • Process: radio astronomy science priorities, and the NRAO Decadal Survey 2010 working group • Five exemplary science programs that demonstrate the synergy between NRAO instruments, and their key roles in modern, multi-wavelength astrophysics.
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1 AUI Cooperative Agreement — NSF Panel Review August 25 – 28, 2008 National Radio Astronomy Observatory Science enabled by NRAO facilities into the next.
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Science enabled by NRAO facilities into the next decade
Chris Carilli• Process: radio astronomy science priorities, and the NRAO Decadal Survey 2010 working group • Five exemplary science programs that demonstrate the synergy between NRAO instruments, and their key roles in modern, multi-wavelength astrophysics.
NRAO/AUI has co-sponsored an extensive series of meetings, advisory committees, and internal discussions, to consider the main science priorities for (radio) astronomy into the next decade:
• Chicago I, II, III: open meetings with broad, multiwavelength input
• Review reports and produce set of key science programs for radio astronomy in the next decade, delineating the role of NRAO facilities in enabling these programs.
• Generate flow-down from science requirements to technical improvements to NRAO facilities, or new facilities, including assessment of technical readiness, (rational) costing, global context (OTC, OSC…)
Goal: Report on role of NRAO in DS2010 for review by user community
Guiding principles
•Attract the broad community: multi-wavelength approach to tackling the key problems in modern astronomy
•NRAO as a ‘single facility’: complementary use of NRAO facilities to produce non-linear gains in scientific discovery
• Science priorities expressed in various venues are generally consistent with the Key Science Projects proposed by the SKA science working group in 2004.
• [Even SKA project office admits full SKA is not realizable in next decade.]
• Near term: Narrow focus to quantify how NRAO facilities will make major strides in addressing the SKA KSP goals, as well as delineate the requisite upgrades, or development work on plausible new facilities.
• Naturally places NRAO DS2010 science planning into global context, with firm-footing based on broad community input.
KSP II: Cosmology -- measure Ho to few % with extragalactic water maser disks.
Why do we need an accurate measure of Ho?
To make full use of 1% measures of cosmological parameters via Planck-CMB studies requires 1% measure of Ho -- covariance!
with Ho constraint
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Measuring Distances to H2O Megamasers
Two methods to determine distance:
• “Acceleration” method
D = Vr2 / a
• “Proper motion” method
D = Vr / (d/dt)
NGC 4258
2Vr
2
D = r/
a = Vr2/r
D = Vr2/a
Vr
Herrnstein et al. (1999)
D = 7.2 0.5 Mpc
• Recalibrate Cepheid distance scale
• Problem: NGC 4258 is too close
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The Project (Braatz et al.) 1. Identify maser disk galaxies with GBT into Hubble flow ~ 50 currently2. Obtain high-fidelity images of the sub-pc disks with the High
Sensitivity Array (VLBA+GBT+Eff+eVLA) ~ 10% are useful3. Measure internal accelerations with GBT monitoring4. Model maser disk dynamics and determine distance to host galaxy
Goal: 3% measure of Ho
GBT
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UGC 3789: A Maser Disk in the Hubble Flow
Discovery: Braatz & Gugliucci (2008)VLBI imaging: Reid et al. (in prep)Distance/modeling: Braatz et al. (in prep)
Acceleration modeling
D ~ 51 MpcHo = 64(+/-7)
Already at HST Key project accuracy with 1 source!
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Dark Ages
Cosmic Reionization
• Major science driver for all future large area telescopes • Last phase of cosmic evolution to be tested • Bench-mark in cosmic structure formation indicating the first luminous sources
Radio astronomy role
• Gas, dust, star formation, in first galaxies
• HI 21cm ‘tomographic imaging’ of neutral IGM
KSP I: Cosmic reionization and first (new) light in the Universe
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• Highest redshift SDSS QSO • Lbol = 1e14 Lo
• Black hole: ~3 x 109 Mo (Willot etal.)• Gunn Peterson trough = near edge of reionization (Fan etal.)
Pushing into reionization: QSO 1148+52 at z=6.4 (tuniv = 0.87Gyr)
GP effect => first galaxies/BH are only observable at near IR through radio wavelengths
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• Dust mass ~ 7e8 Mo
• Gas mass ~ 2e10 Mo
• CO size ~ 6 kpcLow order molecular lines redshift to cm
bands = ‘fuel for gal formation’
mm/cm: Gas, Dust, Star Form, in host galaxy of J1148+5251
1” ~ 6kpc
CO3-2 VLA z=6.42
• 30% of z>6 SDSS QSO hosts are HyLIRGs
• Dust formation associated with high mass star formation?
LFIR = 1.2e13 Lo
MAMBO/IRAM 30m
Only direct observations of host galaxy properties
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FIR excess -- follows Radio-FIR correlation: SFR ~ 3000 Mo/yr
Continuum SED and CO excitation: ISM physics at z=6.42
NGC253
MW
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[CII] 158um at z=6.4: dominant ISM gas coolant
[CII] PdBI Walter et al.
z>4 => FS lines redshift to mm band
L[CII] = 4x109 Lo (L[NII] < 0.1 L[CII])
[CII] similar extension as molecular gas ~ 6kpc => distributed star formation
SFR ~ 6.5e-6 L[CII] ~ 3000 Mo/yr
1”
[CII] + CO 3-2
[CII]
[NII]
IRAM 30m
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Building a giant elliptical galaxy + SMBH at tuniv < 1Gyr
Multi-scale simulation isolating most
massive halo in 3 Gpc^3 (co-mov)
Stellar mass ~ 1e12 Mo forms in series (7) of major, gas rich mergers from z~14, with SFR ~ 1e3 - 1e4 Mo/yr
SMBH of ~ 2e9 Mo forms via Eddington-limited accretion + mergers
Evolves into giant elliptical galaxy in massive cluster (3e15 Mo) by z=0
10.5
8.1
6.5
Li, Hernquist, Roberston..
z=10
• Rapid enrichment of metals, dust, molecules
• Rare, extreme mass objects: ~ 100 SDSS z~6 QSOs on entire sky
• Integration times of hours to days to detect HyLIGRs
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(sub)mm: high order molecular lines. fine structure lines -- ISM physics, dynamics
cm telescopes: low order molecular transitions -- total gas mass, dense gas tracers
Pushing to first normal galaxies: spectral lines
FS lines will be workhorse lines in the study of the first galaxies with ALMA.
Study of molecular gas in first galaxies will be done primarily with cm telescopes
SMA
ALMA will detect dust, molecular and FS lines in ~ 1 hr in ‘normal’ galaxies (SFR ~ 10 Mo/yr = LBGs, LAEs) at z ~ 6, and derive z directly from mm lines.
, GBTGBT
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cm: Star formation, AGN
(sub)mm Dust, cool gas
Near-IR: Stars, ionized gas, AGN
Arp 220 vs z
Pushing to normal galaxies: continuum
A Panchromatic view of galaxy formation
SMA
GBT
eg. GBT = wide field ‘finder’; ALMA = detailed imager
Specific star formation rate = SFR/M* vs. stellar mass
Radio: no dust-bias, SSFR ~ constant w. M* => ‘universality of SF in galaxies’
<UVextinction> ~ 5x, but strong trend with SFR (or M*): key to understanding star form history of Universe
EVLA will detect (individually) 100’s of normal star forming galaxies at high redshift in every deep field at 1.4 GHz
Panella etal
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HI 21cm Tomography of IGM
z=14
7.6
SKA: Direct imaging of evolution of neutral IGM
Pathfinders: statistical detection (power spectrum), largest Stromgren spheres, absorption toward first radio AGN
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Experiments under-way: pathfinders 1% to 10% SKA
MWA (MIT/CfA/ANU)
• NRAO participates on individual basis in path-finders
• NRAO has world-leading expertise in low freq H/W and S/W, and is developing critical wide field imaging software for LWA, EVLA -- additional resources could benefit all experiments
• NRAO has interest in contributing to development of, and potentially operating, next-gen experiment, perhaps parallel mode to FASR project
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Destination: Moon! Low frequency array on far side of Moon by 2025
No interference
No ionosphere
NASA’s top astronomy priority for Presidential initiative to return Man to Moon
2008 NASA Lunar Science Institute: Mission concept study (Colorado, NRL, NRAO, MIT++)
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RIPL Radio Interferometric Planet Search
• Detect Jupiter mass planets around nearby low mass stars through astrometric wobble
• 32 stars– M1 – M8– D = 2.7 – 9.5 pc– 11 are members of known