Radio Astronomy at Cornell

Faculty:Don Campbell

asteroids, comets, planets, radar techniques

Jim Cordescompact objects, interstellar medium, SETI

Riccardo Giovanelligalaxies & large-scale structure of the universe

Paul Goldsmithmolecular clouds, star formation, instrumentation

Martha Haynesgalaxies & large-scale structure of the universe

Yervant Terzianinterstellar medium, planetary nebulae, binary galaxies

Radio Astronomy at Cornell

Students & Postdocs:10 graduate students doing research with a major radio/radar astronomy component

International collaborations using all available astronomical resources

2 postdocs (extragalactic science, pulsars, masers, the Square Kilometer Array

Undergraduates regularly work in radio research groups(observing trips to Puerto Rico, Palomar, etc., conferences,co-authoring papers, overall participation in the scientific enterprise)

Other Facilities

Essentially all major radio facilities in the world VLA, VLBA, GBT, FCRAO (mm), Parkes, Goldstone (DSN)

Optical observatories (Palomar)

Space observatories GRO, HST, SWAS, Chandra, SIRTF, GLAST

Computational: > 100 CPUs in SSB (solaris/linux/wintel)

Cornell Theory Center (~120 nodes)

The Green Bank Telescope

(WVa.)

VLBA AstrometryPSR B0919+06S. Chatterjee et al. (2000) = 88.5 0.13 mas/yr = 0.83 0.13 mas

D = 1.2kpcV = 505 km/s

Radar detection of ice deposits on Mercury

Don Campbell

+ Arecibo collaborators

+ students

216 Kleopatra(main-belt asteroid ~217 x 94 km)

1999 JM8 = Earth Crossing Asteroid

B 1012 Gauss

gNS 1011 g

FEM 109 gNS mp

1013 volts

Surface quantitiesPulsar

Bound & Escaping NS Populations

B2224+65 > 1000 km/s J0437-4715 ~ 90 km/sB1957+20 ~ 100 km/s

H

Extragalactic Group

Counterrotating Disks in Galaxies:

Dwarf galaxies: abundances, morphology, star formation

Other Extragalactic projects

• Studies of the local reference frame with respect to large-scale structure

• Combined HI, IR and optical studies of galaxies (rotation curves, morphology)

• OH megamasers as a powerful method for quantifying star formation vs. redshift (Jeremy Darling PhD thesis)

Molecular Line Studies

• Contents of molecular clouds in star-forming regions (CO and HI relationship)

• Chemistry of molecule production in clouds

• SWAS (Submillimeter Wave Astronomy Satellite): evidence for comet destruction in envelope of red-giant star.

Planetary Nebulae & White Dwarfs

Nature of bipolarity

Motion of shells

Energetics

Parkes MB Feeds

ALFA = Arecibo L-band Feed Array(1.4 GHz)

• Cornell faculty, students heavily involved– Instrumentation, software, science planning, surveys

• Major surveys to commence in early 2005• International science consortia

– Pulsars

– Galactic science

– Extragalactic science

• SETI

ALFA Surveys• Deep pulsar surveys

• ~1000 new pulsars• NS-NS, NS-BH binaries• Submillisecond pulsars

• Galactic plane hydrogen surveys• Phase structure of the ISM• Supershells and chimneys

• High-velocity clouds (tidal debris vs. primordial)• Extensive surveys for galaxies

• Zone of avoidance• Low mass galaxies

• SETI• Deepest survey of the Galactic plane ever done

The Square Kilometer Array• International project• Substantial Cornell involvement• 20x sensitivity of Arecibo• Will look like the VLA + VLBA

(e.g. 5000 12-m antennas)• > 2010!• Prototypes expected in this decade• Growing involvement of NAIC with the SKA and

related projects• Opportunities for undergraduate participation

Current ConceptsCurrent ConceptsChina KARSTChina KARST

Canadian Canadian aerostataerostat

US Large NUS Large N

Australian Australian Luneburg Luneburg LensesLenses

Dutch fixed Dutch fixed planar arrayplanar array

(cf. Allen Telescope Array,

Extended VLA)

(cf. LOFAR = Low Freqency Array)

Also cylindrical reflectors

Radio Astronomy at Cornell

Students & postdocs:10 graduate students doing research with a major radio/radar astronomy component

Multiwavelength (radio to gamma-rays)

Collaborations with other departmental groups (IR, theory, planetary)

Multi-institution collaborations

2 postdocs at present working on extragalactic science, pulsars, masers and the Square Kilometer Array

Recent VLBI

Extragalactic GroupCounterrotating Disks in Galaxies

Dwarf galaxies: abundances, morphology, star formation

Studies of the Tully-Fisher Relation and Peculiar Velocities in the Local Universe

Surveys with Surveys with Parkes, Parkes, Arecibo & Arecibo & GBT.GBT.

Simulated & Simulated & actualactual

Yield ~ 1000 Yield ~ 1000 pulsars.pulsars.

• The sky at different wavelengths

• Advantages of radio astronomy

• What do we see?

• New surveys with the upgraded Arecibo Telescope

• The Square Kilometer Array

REMOTE SENSING THE UNIVERSEWITH RADIO WAVES

Jim Cordes, Cornell University

9 June 2001

THE MILKY WAY

optical

THE MILKY WAY

optical

Andromeda(M31)

THE MILKY WAY

optical

infrared

THE MILKY WAY

Radio(408 MHz

X-rays

Advantages of Radio Sensing

• The Galaxy and the universe are mostly transparent to radio waves (except when the U. was younger

than 300,000 yr)

• The radio sky looks very different thanother wavelengths

• Some objects in the universe appear only as radio objects.

B 1012 Gauss

gNS 1011 g

FEM 109 gNS mp

1013 volts

Surface quantitiesPulsar

The Very Large Array

(New Mexico)

Arrays of antennas are used to make radio

images of the sky

Radio Galaxy

Very Long Baseline Array

PSR B0919+06S. Chatterjee et al. (2001) = 88.5 0.13 mas/yr = 0.83 0.13 mas

D = 1.2kpcV = 505 km/s

Parkes MB Feeds

Surveys Surveys with Parkes, with Parkes, Arecibo & Arecibo & GBT.GBT.

Simulated & Simulated & actualactual

Yield ~ 2000 Yield ~ 2000 pulsars.pulsars.

Square Kilometer Array Square Kilometer Array

Current ConceptsCurrent Concepts

China KARSTChina KARST

Canadian Canadian aerostataerostat

US Large NUS Large N

Australian Australian Luneburg Luneburg LensesLenses

Dutch fixed Dutch fixed planar arrayplanar array

(cf. Allen Telescope Array,

Extended VLA)

(cf. LOFAR = Low Freqency Array)

SKA pulsar SKA pulsar surveysurvey

600 s per 600 s per beambeam

~10~1044 psr’s psr’s

Forks in the Roadsupernova nada

prompt black hole

neutron star

other?neutron stars

black hole

canonical pulsar (1012 G)NS

magnetar, SGR (1015 G)

other

fallback

PSR 0355+54 Cass A

No periodicity or single pulses detected

(McLaughlin et al. 2000)

Chandra image of Cass A

Background:

1932: neutron discovered

1933: neutron stars (Baade & Zwicky)

l939: first models (Oppenheimer & Volkoff)

Detectability? Thermal (106 K, 10 km) bleak

1967: Radio pulsars (serendipitous)Gamma-ray bursts (ditto)

1968: Pulsar discovery announcedCrab pulsar discovered

1969: Crab pulsar spindown measured& clinched the NS hypothesis (T. Gold)

Neutron Stars

Manifestations of NS• Rotation driven:

• “radio” pulsars (radio rays)

• magnetic torque (Edot Idot I B2 4 ) e+ e- + plasma instability coherent radio

• Accretion driven:• X-rays Lx = Mdot c2

• LMXB, HMXB

• Magnetic driven? Crustquakes?• Magnetars (AXPs, SGRs)

• Spindown … but Lx > Edot

• Gravitational catastrophes?• Gamma-ray bursts, G.wave sources, hypernovae?

B 1012 Gauss

gNS 1011 g

FEM 109 gNS mp

1013 volts

Surface quantities

B2 P Pdot

B2 P Pdot

= P / 2Pdot

Bound & Escaping NS Populations

B2224+65 > 1000 km/s J0437-4715 ~ 90 km/sB1957+20 ~ 100 km/s

H

H Images of Pulsar Bow Shocks

Guitar Nebula (1600 km/s)MSP J0437-47 (100 km/s)

Independent Pulsar Distances

• Parallaxes: Timing, Interferometry

• Associations: Supernova remnants, Globular clusters

• HI Absorption: Kinematic gal. model

Proper Motions of Pulsars

• Interferometry (VLA, MERLIN, VLBA)• mas/yr - arcsec/yr

• Timing• microsec - ms

• Interstellar Scintillation• intensity (t, )

(minutes, MHz)

VLBA AstrometryPSR B0919+06S. Chatterjee et al. (2000) = 88.5 0.13 mas/yr = 0.83 0.13 mas

D = 1.2kpcV = 505 km/s