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Radio Astronomy at Cornell
Faculty:
Don Campbell
asteroids, comets, planets, radar techniques
Jim Cordes
compact objects, interstellar medium, SETI
Riccardo Giovanelli
galaxies & large-scale structure of the universe
Paul Goldsmith
molecular clouds, star formation, instrumentation
Martha Haynes
galaxies & large-scale structure of the universe
Yervant Terzian
interstellar 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 Astrometry
PSR B0919+06
S. Chatterjee et al. (2000)
 = 88.5  0.13 mas/yr
 = 0.83  0.13 mas
D = 1.2kpc
V = 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
Pulsar
Surface quantities
B  1012 Gauss
gNS  1011 g
FEM  109 gNS mp
  1013 volts
Bound & Escaping NS Populations
B2224+65 > 1000 km/s
H
B1957+20
~ 100 km/s
J0437-4715 ~ 90 km/s
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 starforming 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
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•
•
•
•
•
•
•
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
China KARST
Current Concepts
Canadian
aerostat
US Large N
(cf. Allen Telescope Array,
Extended VLA)
Australian
Luneburg
Lenses
Dutch fixed
planar array
Also cylindrical
reflectors
(cf. LOFAR = Low Freqency
Array)
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 Group
Counterrotating Disks in Galaxies
Dwarf galaxies:
abundances,
morphology, star
formation
Studies of the Tully-Fisher Relation and
Peculiar Velocities in the Local Universe
Surveys with
Parkes,
Arecibo &
GBT.
Simulated &
actual
Yield ~ 1000
pulsars.
REMOTE SENSING THE UNIVERSE
WITH RADIO WAVES
Jim Cordes, Cornell University
9 June 2001
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•
•
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The sky at different wavelengths
Advantages of radio astronomy
What do we see?
New surveys with the upgraded
Arecibo Telescope
• The Square Kilometer Array
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 than
other wavelengths
• Some objects in the universe appear only
as radio objects.
Pulsar
Surface quantities
B  1012 Gauss
gNS  1011 g
FEM  109 gNS mp
  1013 volts
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+06
S. Chatterjee et al. (2001)
 = 88.5  0.13 mas/yr
 = 0.83  0.13 mas
D = 1.2kpc
V = 505 km/s
Parkes MB Feeds
Surveys
with Parkes,
Arecibo &
GBT.
Simulated &
actual
Yield ~ 2000
pulsars.
China KARST Square Kilometer Array
Current Concepts
Canadian
aerostat
US Large N
(cf. Allen Telescope Array,
Extended VLA)
Australian
Luneburg
Lenses
Dutch fixed
planar array
(cf. LOFAR = Low Freqency
Array)
SKA pulsar
survey
600 s per
beam
~104 psr’s
Forks in the Road
supernova
nada
prompt black hole
neutron star
other?
neutron stars
fallback
black hole
canonical pulsar (1012 G)
NS
magnetar, SGR (1015 G)
other
Chandra image of Cass A
No periodicity or single
pulses detected
(McLaughlin et al. 2000)
PSR 0355+54
Cass A
Neutron Stars
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 announced
Crab pulsar discovered
1969:
Crab pulsar spindown measured
& clinched the NS hypothesis (T. Gold)
Manifestations of NS
• Rotation driven:
• “radio” pulsars (radio   rays)
• magnetic torque (Edot  Idot  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?
Surface quantities
B  1012 Gauss
gNS  1011 g
FEM  109 gNS mp
  1013 volts
B2  P Pdot
B2  P Pdot
 = P / 2Pdot
Bound & Escaping NS Populations
B2224+65 > 1000 km/s
H
B1957+20
~ 100 km/s
J0437-4715 ~ 90 km/s
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 Astrometry
PSR B0919+06
S. Chatterjee et al. (2000)
 = 88.5  0.13 mas/yr
 = 0.83  0.13 mas
D = 1.2kpc
V = 505 km/s