1. Current and Future Science with NRAO Instruments
National Radio Astronomy Observatory
NRAO Operations Review ~ February 29 – March 1, 2008
Current and Future Science with NRAO Instruments
Chris Carilli
Current large programs: snapshot of major scientific use of NRAO telescopes.
Four exemplary science programs that demonstrate the synergy between NRAO instruments, and their key roles in modern, multiwavelength astrophysics.
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, TeV sources explained!

2. 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 B2 and TMC-1 -- GBT
Detecting nHz 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

3. Radio studies of the first galaxies: gas, dust, star formation, into cosmic reionization
Dark Ages
Last phase of cosmic evolution to be tested
Bench-mark in cosmic structure formation indicating the first luminous sources
Major science driver for all future large area telescopes
Cosmic Reionization

4. Pushing into reionization: QSO 1148+52 at z=6.4 (tuniv = 0.87Gyr)
Highest redshift SDSS QSO
Lbol = 1e14 Lo
Black hole: ~3 x 109 Mo (Willot etal.)
Gunn Peterson trough = near edge of reionization (Fan etal.)

5. mm/cm: Gas, Dust, Star Form, in host galaxy of J1148+5251
CO3-2 VLA z=6.42
MAMBO/IRAM 30m
LFIR = 1.2e13 Lo
1” ~ 6kpc
Dust formation? AGB Winds take > 1.4e9yr > age Universe
=> dust formation associated with high mass star formation (Maiolino+ 07, Dwek+ 2007, Shull+ 2007)?
Dust mass ~ 7e8 Mo
Gas mass ~ 2e10 Mo
CO size ~ 6 kpc
Note: low order molecular lines redshift to cm bands

6. Continuum SED and CO excitation: ISM physics at z=6.42
Elvis QSO SED
50K
Radio-FIR correlation
NGC253
FIR excess -- follows Radio-FIR correlation: SFR ~ 3000 Mo/yr
CO excitation ~ starburst nucleus: Tkin ~ 100K, nH2 ~ 1e5 cm^-3

7. [CII] 158um at z=6.4: dominant ISM gas coolant
IRAM 30m
z>4 => FS lines redshift to mm band
[CII] traces star formation: similar extension as molecular gas ~ 6kpc
L[CII] = 4x109 Lo (L[NII] < 0.1 L[CII])
SFR ~ 6.5e-6 L[CII] ~ 3000 Mo/yr
[CII]
[NII] 1”
[CII] PdBI Walter et al.
[CII] + CO 3-2

8. Building a giant elliptical galaxy + SMBH at tuniv < 1Gyr
z=10
10.5
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
Li, Hernquist, Roberston..
8.1
6.5
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

9. Pushing to first normal galaxies: spectral lines
SMA
Pushing to first normal galaxies: spectral lines
cm telescopes: low order molecular transitions -- total gas mass, dense gas tracers
, GBT
(sub)mm: high order molecular lines. fine structure lines -- ISM physics, dynamics
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
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.

10. (sub)mm Dust, molecular gas Near-IR: Stars, ionized gas, AGN
Pushing to normal galaxies: continuum
A Panchromatic view of galaxy formation
Arp 220 vs z
SMA
cm: Star formation, AGN
(sub)mm Dust, molecular gas
Near-IR: Stars, ionized gas, AGN

11. II. Cosmic geometry: Ho to few % with water maser disks
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!
Current Ho constraint
Current Ho constraint

12. Measuring Distances to H2O Megamasers
NGC 4258
Two methods to determine distance:
“Acceleration” method
D = Vr2 / a
“Proper motion” method
D = Vr / (d/dt)  Vr
D = r/
2Vr
2
a = Vr2/r
D = Vr2/a
Recalibrate Cepheid distance scale
Problem: NGC 4258 is too close
Earth baselines => resolution > 0.4 mas => max. distance ~ 120 Mpc
Herrnstein et al. (1999)
D = 7.2  0.5 Mpc

13. The Project (Braatz et al.)
Identify maser disk galaxies with GBT into Hubble flow ~ 50 currently
Obtain high-fidelity images of the sub-pc disks with the High Sensitivity Array (VLBA+GBT+Eff+eVLA) ~ 10% are useful
Measure internal accelerations with GBT monitoring
Model maser disk dynamics and determine distance to host galaxy
GBT
Goal: 3% measure of Ho

14. UGC 3789: A Maser Disk in the Hubble Flow
Acceleration modeling
D ~ 51 Mpc
Ho = 64
(tentative)
Discovery: Braatz & Gugliucci (2008)
VLBI imaging: Reid et al. (in prep)
Distance/modeling: Braatz et al. (in prep)

15. III. Protoplanetary disks and planet formation
SMA 350 GHz detection of proplyds in Orion
Derive dust mass (>0.01Mo), temperature
HST
Williams et al.

16. TW Hya Disk: VLA observations of planet formation
Pre-solar nebula analog
50pc distance
star mass = 0.8Mo
Age = Myr
mid IR deficit => disk gap caused by large planet formation at ~ 4AU?
Calvet et al. 2002
mid-IR “gap”
cm slope ”pebbles”
VLA imaging on AU-scales:
consistent with disk gap model
cm probes grains sizes between ISM dust and planetesimals (~1cm)
Dec= -34
Hughes, Wilner +

17. Birth of planets: The ALMA/EVLA revolution
ALMA 850 GHz, 20mas res.
Wolfe +
Wilner
Radius = 5AU = 0.1” at 50pc
Mass ratio = 0.5MJup /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

18. IV. At the extremes of physics
Extreme gravity: using pulsars to detect nHz gravity waves and explore strong field GR
TeV sources: explained!
Credit: Bill Saxton, NRAO

19. 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 5-10 years
Timing precision depends on
- sensitivity (G/Tsys) (i.e. GBT and Arecibo)‏
- optimal instrumentation (GUPPI -- wideband pulsar BE)
Predicted timing residuals
Predicted timing residuals
D. Backer

20. NanoGrav
Credit: D. Manchester, G. Hobbs

21. GR tests: Timing of the Double Pulsar J0737-3039
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

22. LS I +61 303: Solving the TeV mystery
Harrison
Xray
Discovered 100 MeV; variable 5 GHz emission.
High mass binary: 12 Mסּ Be * , 1– 3Mסּ NS or BH.
Eccentric orbit e=0.7, period days.
X-rays peak @ periastron, radio cycle later.
TeV detected by Magic
MODELS:
Accretion powered relativistic jet (microQuasar?)
Compact pulsar wind nebula
Radio
> 400 GeV
Albert+ 2006

23. VLBA Images vs. Orbital Phase (orbit exaggerated)
VLBA resolution ~ 2AU
Dhawan + Be
VLBA movie shows 'cometary' morphology => a Pulsar Wind Nebula shaped by the Be star envi- ronment, not a relativistic jet.

24. 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.

25. 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 will 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

26. END

27. Accretion onto compact objects
Now: bright black holes
ADAF, JDAF
Jet outflows & state of accretion disk
EVLA + VLBA
Bondi accretion onto single BH in molecular cloud
NS, WD: role of event horizon, magnetic field, spin
1e-6 Mdot,Edd at GalCtr (1 Msun)
Ledd for 10Msun at M81
10-4 LE
(1 Msun)
Radio LE
(1 Msun)
Fender, Migliari, Gallo, Jonker, et al.
(this one: Migliari & Fender 2007)
Soft X-ray