National Radio Astronomy Observatory NRAO Operations Review February
National Radio Astronomy Observatory NRAO Operations Review ~ February 29 – March 1, 2008 Current and Future Science with NRAO Instruments Chris Carilli 1. Four exemplary science programs that demonstrate the synergy between NRAO instruments, and their key roles in modern, multiwavelength astrophysics. a. b. c. d. First galaxies: gas, dust, star formation into cosmic reionization Cosmic geometry: Megamasers and a 3% measure of Ho Protoplanetary disks: imaging planet formation At the extremes of physics: strong field GR, Te. V sources explained! 1
Dark Ages Cosmic Reionization I. Radio studies of the first galaxies: gas, dust, star formation, into 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 2
Pushing into reionization: QSO 1148+52 at z=6. 4 (tuniv = 0. 87 Gyr) • Highest redshift SDSS QSO • Lbol = 1 e 14 Lo • Black hole: ~3 x 109 Mo (Willot etal. ) • Gunn Peterson trough = near edge of reionization (Fan etal. ) 3
mm/cm: Gas, Dust, Star Form, in host galaxy of J 1148+5251 CO 3 -2 VLA z=6. 42 MAMBO/IRAM 30 m LFIR = 1. 2 e 13 Lo 1” ~ 6 kpc • Dust mass ~ 7 e 8 Mo • Gas mass ~ 2 e 10 Mo • CO size ~ 6 kpc Note: low order molecular lines redshift to cm bands • 30% of z>6 SDSS QSO hosts are Hy. LIRGs • Dust formation? AGB Winds take > 1. 4 e 9 yr > age Universe => dust formation associated 4 with high mass star formation?
Continuum SED and CO excitation: ISM physics at z=6. 42 Elvis QSO SED Radio-FIR correlation 50 K NGC 253 MW § FIR excess -- follows Radio-FIR correlation: SFR ~ 3000 Mo/yr § CO excitation ~ starburst nucleus: Tkin ~ 100 K, n. H 2 ~ 1 e 5 cm^-3 5
[CII] 158 um at z=6. 4: dominant ISM gas coolant § z>4 => FS lines redshift to mm band IRAM 30 m [CII] § L[CII] = 4 x 109 Lo (L[NII] < 0. 1 L[CII]) §[CII] similar extension as molecular gas ~ 6 kpc => distributed star formation § SFR ~ 6. 5 e-6 L[CII] ~ 3000 Mo/yr [NII] 1” [CII] Pd. BI Walter et al. [CII] + CO 3 -2 6
Building a giant elliptical galaxy + SMBH at tuniv < 1 Gyr § Multi-scale simulation isolating most massive halo in 3 Gpc^3 (co-mov) 10. 5 z=10 Li, Hernquist, Roberston. . 8. 1 § Stellar mass ~ 1 e 12 Mo forms in series (7) of major, gas rich mergers from z~14, with SFR ~ 1 e 3 - 1 e 4 Mo/yr § SMBH of ~ 2 e 9 Mo forms via Eddington-limited accretion + mergers 6. 5 § Evolves into giant elliptical galaxy in massive cluster (3 e 15 Mo) by z=0 • 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 Hy. LIGRs 7
Pushing to first normal galaxies: spectral lines SMA cm telescopes: low order molecular transitions -- total gas mass, dense gas tracers , GBT (sub)mm: high order molecular lines. fine structure lines -- ISM §FS lines will be workhorse lines in the study of the first galaxies ALMA. physics, with dynamics §Study of molecular gas in first galaxies will be done primarily with cm telescopes ALMA will detect dust, molecular and FS lines in ~ 1 hr in ‘normal’ galaxies (SFR ~ 10 Mo/yr = LBGs, LAEs) at z ~ 6, and 8 derive z directly from mm lines.
Pushing to normal galaxies: continuum A Panchromatic view of galaxy formation Arp 220 vs z SMA cm: Star formation, AGN (sub)mm Dust, cool gas Near-IR: Stars, ionized gas, AGN 9
II. Cosmic geometry: Ho to few % with 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 10
Measuring Distances to H 2 O Megamasers NGC 4258 Vr Two methods to determine distance: • D = Vr 2 / a D = r/ 2 Vr a = Vr 2/r D= Vr 2/a “Acceleration” method • “Proper motion” method D = Vr / (d /dt) 2 Herrnstein et al. (1999) D = 7. 2 0. 5 Mpc • Recalibrate Cepheid distance scale • Problem: NGC 4258 is too close 11
The Project (Braatz et al. ) 1. Identify maser disk galaxies with GBT into Hubble flow ~ 50 currently 2. Obtain high-fidelity images of the sub-pc disks with the High Sensitivity Array (VLBA+GBT+Eff+e. VLA) ~ 10% are useful 3. Measure internal accelerations with GBT monitoring 4. Model maser disk dynamics and determine distance to host galaxy GBT Goal: 3% measure of Ho 12
UGC 3789: A Maser Disk in the Hubble Flow Acceleration modeling D ~ 51 Mpc Ho = 64 (+/-7) Discovery: Braatz & Gugliucci (2008) VLBI imaging: Reid et al. (in prep) Distance/modeling: Braatz et al. (in prep) Already at HST Key project accuracy with 1 source! 13
III. Protoplanetary disks and planet formation • SMA 350 GHz detection of proplyds in Orion • Derive dust mass (>0. 01 Mo), temperature HST Williams et al. 14
TW Hya Disk: VLA observations of planet formation Pre-solar nebula analog Calvet et al. 2002 • 50 pc distance • star mass = 0. 8 Mo mid-IR “gap” • Age = 5 -- 10 Myr • mid IR deficit => disk gap caused by large planet formation at ~ 4 AU? cm slope ”pebbles” 15
TW Hya Disk: VLA observations of planet formation VLA imaging on AU-scales: • consistent with disk gap model • cm probes grains sizes between ISM dust and planetesimals (~1 cm) Dec= -34 Hughes, Wilner + 16
Birth of planets: The ALMA/EVLA revolution ALMA 850 GHz, 20 mas res. Wolfe + Radius = 5 AU = 0. 1” at 50 pc Wilner Mass ratio = 0. 5 MJup /1. 0 Msun • ALMA: AU-scale imaging of dust, gas, unhindered by opacity, nor confused by the central star • EVLA: AU-scale imaging of large dust grain emission • JWST: image dust shadow on scales 10’s mas • Herschel: dust spectroscopy 17
TW Hya -- Molecular gas SMA: Gas mass, rotation ALMA: dynamics at sub-AU, subkm/s resolution SMA ALMA simulation Wilner 18
IV. At the extremes of physics • Extreme gravity: using pulsars to detect n. Hz gravity waves • Te. V sources: explained by VLBI! Credit: Bill Saxton, NRAO
Gravitational Wave Detection using a ‘pulsar timing array’ with NANOGrav (Demorest +) • Need ~20 -40 MSPs with ~100 ns timing RMS • bi-weekly, multi-freq obs for 510 years • Timing precision depends on - sensitivity (G/Tsys) (i. e. GBT and Arecibo) - optimal instrumentation (GUPPI -- wideband pulsar BE) Predicted timing residuals D. Backer
Nano. Grav Credit: D. Manchester, G. Hobbs
LS I +61 303: Solving the Te. V mystery ● Discovered 1976 @ 100 Me. V; variable 5 GHz emission. ● High mass binary: 12 M סּ Be * , 1– 3 M סּ NS or BH. ● Eccentric orbit e=0. 7, period 26. 5 days. ● X-rays peak @ periastron, radio 0. 5 cycle later. ● Te. V detected by Magic ● MODELS: Harrison + 2000 Xray Radio > 400 Ge. V Albert+ 2006 (A) Accretion powered relativistic jet (micro. Quasar? ) (B) Compact pulsar wind nebula 22
VLBA Images vs. Orbital Phase (orbit exaggerated) VLBA resolution ~ 2 AU Dhawan + Be VLBA movie shows 'cometary' morphology => a Pulsar Wind Nebula shaped by the Be star environment, not a relativistic jet.
Gamma-Rays from AGN Jets • GLAST launch scheduled for May 2008 • VLBA jet imaging on pc -scales during flares required to understand gamma ray production • Prelaunch survey: VIPS project to image 1100 objects (Taylor et al. ) • Planned: 43 GHz + GLAST monitoring of gamma ray blazars Marscher et al. 24
NRAO in the modern context Golden age of astrophysics: NRAO telescopes play a fundamental role in topical areas of modern astrophysics • Precision cosmology: setting the baseline (Planck ++) • Galaxy evolution and first (new) light: gas, dust, star formation (JWST, TMT) • Birth of stars and planets: dust and gas on AU scales (JWST, Herschel) • Testing basic physics: GR, fundamental constants, … (LIGO, LISA) • Resolving high energy phenomena: a ray source primer (GLAST, CONX) Capabilities into next decade keep NRAO on the cutting edge • ALMA -- biggest single step ever in ground based astronomy • EVLA -- the premier cm telescope on the planet, and a major step to the SKA • GBT -- just hitting its stride, with pending FPA revolution • VLBA -- Mankind’s highest resolution instrument 25
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Current large programs: VLA, VLBA, GBT • Radio interferometric planet search -- VLBA, VLA, GBT • Coordinated radio and infrared survey for high mass star formation -- VLA • Definitive test of star formation theory -- GBT • Legacy survey of prebiotic molecules toward Sgr B 2 and TMC-1 -- GBT • Detecting n. Hz gravitational radiation using pulsar timing array -- GBT • Star Formation History and ISM Feedback in Nearby Galaxies -- VLA • LITTLE THINGS survey: HI in dwarf galaxies -- VLA • Megamaser cosmology project -- GBT, VLBA, VLA • Probing blazars through multi-waveband variability of flux, polarization, and structure -- VLBA • MOJAVE/GLAST program: mas imaging of gamma ray sources -- VLBA • VLA low frequency sky survey -- VLA • Deep 1. 4 GHz observations of extended CDFS -- VLA AUI Operations Review February 29 – March 1, 2008 27
GR tests: Timing of the Double Pulsar J 0737 -3039 GBT provides the best timing precision for this system 6 post-Keplerian orbital terms give neutron star masses strong-field tests of GR to 0. 05% accuracy Measure relativistic spin precession: Obs = 5. 11+/- 0. 4 deg/yr GR = 5. 07 deg/yr Kramer et al. , 2006, Science, 314, 97
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