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AUI Cooperative Agreement — NSF Panel ReviewAugust 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.
2AUI Cooperative Agreement Proposal NSF Panel ReviewAugust 25 – 28, 2008
Gauging the community
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
• NRAO 50th anniversary science meeting
• NRAO scientific staff retreats
• NRAO strategic planning retreats
• GBT, ALMA science workshops
• AAS townhall discussions
• McCray committee
3AUI Cooperative Agreement Proposal NSF Panel ReviewAugust 25 – 28, 2008
Decade Survey 2010 Working Group
• 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
4AUI Cooperative Agreement Proposal NSF Panel ReviewAugust 25 – 28, 2008
DS2010 Working Group: Initial deliberations
• 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.
5AUI Cooperative Agreement Proposal NSF Panel ReviewAugust 25 – 28, 2008
Key Science Projects: (i) Address critical questions, (ii) Unique role of radio, or
complementary but fundamental, (iii) Excites broad community
I. Cosmic reionization and first (new) light: (i) HI 21cm tomography of IGM, (ii) gas, dust, star formation in first galaxies
II. Galaxy evolution and cosmology (BAO): all-sky HI + continuum survey
III. Cosmic magnetism -- origin and evolution: all sky RM survey
IV. Strong field tests of GR using pulsars
V. Cradle of Life: star and planet formation, astrochemistry/biology, SETI
JWST primary science goals:
•The end of the dark ages: first light and reionization
•The assembly of galaxies and SMBH
•The birth of stars and proto-planetary systems
•Planets and the origins of life
6AUI Cooperative Agreement Proposal NSF Panel ReviewAugust 25 – 28, 2008
Table 1: Science drivers for future large area telescopes
Science theme Telescope Radio role Galaxy/Black hole evolution (KSP II) EVLA, VLBA, GBT, ALMA, TMT,
JWST, Herschel gas, dust, star form, dynamics, BHs
First light and reionization (KSP I)
EVLA, ALMA, TMT, JWST
IGM (21cm), gas, dust, star form, dyn, BHs
Planets and proto-planetary disks (KSP V)
EVLA, ALMA, TMT, JWST
Sub-AU imaging, extrasolar Jupiter bursts
Cosmology: geometry of Universe, dark energy… (KSP II)
VLBA, GBT, LSST, SNAP…
Ho via maser disks, wide field HI surveys
Star formation (KSP V)
EVLA, GBT, ALMA, JWST, Herschel
gas, dust, dynamics, chemistry
Extremes of physics: Testing GR, extreme states of matter, GBRs, XRBs, relativistic jets… (KSP IV)
GBT, EVLA, VLBA, GLAST, ConX, LIGO
Pulsars, magnetars, submas imaging
Multi-wavelength approach to addressing key questions in modern astrophysics
7AUI Cooperative Agreement Proposal NSF Panel ReviewAugust 25 – 28, 2008
Power of radio astronomy
• Seeing through dust: earliest phases of star and galaxy formation
• Cool universe: thermal emission from gas, dust = fuel for star and galaxy formation
• as astrometry
• sub-mas imaging
• m/s velocity resolution
• Accurate polarimetry -- magnetic fields on all scales
• Chemistry and bio-tracers
HST + OVRO CO
VLA polarization
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HST
• SMA 350 GHz detection of proplyds in Orion
• Derive dust mass (>0.01Mo), temperature
KSP V: Protoplanetary disks and planet formation
Williams et al.
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TW Hya Disk: VLA observations of planet formation
Calvet et al. 2002
mid-IR “gap”
cm slope ”pebbles”
Pre-solar nebula analog
• 50pc distance
• star mass = 0.8Mo
• Age = 5 -- 10 Myr
• mid IR deficit => disk gap caused by large planet formation at ~ 4AU?
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TW Hya Disk: VLA observations of planet formation
Hughes, Wilner +
VLA imaging on AU-scales:
• cm probes grains sizes between ISM dust and planetesimals (~1cm)
• Double-peak morphology is consistent with disk gap model
Dec= -34
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ALMA 850 GHz, 20mas
Wolfe +
Birth of planets: The ALMA/EVLA revolution
Radius = 5AU = 0.1” at 50pc
Mass ratio = 0.5MJup /1.0 Msun
Wilner
• ALMA: AU-scale imaging of dust, gas, unhindered by opacity, nor confused by the central star, on 10mas scale -- secular changes on yearly timescales
• EVLA: AU-scale imaging of large dust grain emission (PT link gives fact 2 improvement in resolution)
• JWST: image dust shadow on scales 40 mas
• Herschel: dust spectroscopy
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Infrared Dark Clouds (IRDCs)
0.5o
Extinction features seen in silhouette against the Galactic IR background
1,000s seen in the Spitzer GLIMPSE survey (and previous surveys like MSX)
Eg
an
et
al. (
199
8);
Care
y e
t al. (
200
0);
Sm
ith
et
al. (
200
6);
Rath
born
e e
t al.
(200
6);
Pill
ai et
al. (
200
6)
and
many
oth
ers
Sites of the earliest phases of massive star formation
3.6 m 4.5 m 8.0 m
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Mapping the Galactic Web of Dense Molecular Gas in IRDCs: Initial Conditions of Massive Star Formation
VLA 3-pointing NH3 mosaic
• Velocity => distance
• Dense gas tracer: physical conditions, chemical evolution
• Many hours observing: not an efficient way to survey
Devin
e e
t al. in
2’
GBT 1.3 cm heterodyne focal plane arrays
large area mapping of NH3 ~ GLIMPSE
essential to understand the initial conditions of massive star formation
KSP IV: Gravitational wave detection using a ‘pulsar timing array’ (NANOGrav, Demorest +)
D. Backer
Predicted timing residualsPredicted timing residuals
• Need ~20-40 MSPs with ~100 ns timing RMS
• bi-weekly obs for 5-10 years
• Timing precision depends on
- sensitivity (G/Tsys) (i.e. GBT and Arecibo)
- optimal instrumentation (GUPPI -- wideband pulsar BE)
Credit: D. Manchester, G. Hobbs
NanoGrav
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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
CO excitation ~ starburst nucleus: Tkin ~ 100K, nH2 ~ 1e5 cm-3
Radio-FIR correlation
50KElvis QSO SED
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
28AUI Cooperative Agreement Proposal NSF Panel ReviewAugust 25 – 28, 2008
END
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1.4 GHz stacking: 30,000 z~2 ‘normal’ galaxies in COSMOS
Current VLA ~ 40 uJy detections; Stacking => 2 +/- 0.2 uJy
2e10 Mo3e11
Radio-derived
UV-derived (w/o dust corr.)
100 Mo/yr10 Mo/yr
5x
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
binary or multiple systems
• 12 epochs/star/3 years– VLBA + GBT– 512 Mb/s– 1392 hours total
Bower et al.
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TW Hya -- Molecular gas
SMA: Gas mass, rotation
ALMA: dynamics at sub-AU, sub-km/s resolution
SMA
ALMA simulation
Wilner