HTRA Galway - June 2006 Dainis Dravins Lund Observatory
Jan 15, 2016
HTRA Galway - June 2006HTRA Galway - June 2006
Dainis Dravins
Lund Observatory
What information is contained in light?
What is being observed ? What is not ?
Quantum optics in astronomy?Quantum optics in astronomy?
BLACKBODY ---
SCATTERED ---
SYNCHROTRON ---
LASER ---
CHERENKOV ---
COHERENT ---
WAVELE
NG
TH
& P
OLA
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ATIO
N F
ILTERS
OBSERVER
Intensity interferometryIntensity interferometry
Narrabri stellar intensity interferomer circa 1970 (R.Hanbury Brown, R.Q.Twiss et al., University of Sydney)
Intensity interferometryIntensity interferometry
R.Hanbury Brown, J.Davis, L.R.Allen, MNRAS 137, 375 (1967)
Roy Glauber
Nobel prize in physics
Stockholm, December 2005
Roy Glauber in Lund, December 2005
Information content of light. IInformation content of light. I
D.Dravins, ESO Messenger No. 78, 9
Galileo’s telescopes (1609)
Instruments measuring first-order spatial coherence
Hubble Space Telescope (1990)
HARPS (2003)
Fraunhofer’s spectroscope (1814)
Instruments measuring first-order temporal coherence
“COMPLEX” RADIATION SOURCES
What can a [radio] telescope detect?
What can it not?
Information content of light. IIInformation content of light. II
D.Dravins, ESO Messenger No. 78, 9
R. Loudon The
Quantum Theory of
Light (2000)
PHOTON STATISTICS
Semi-classical model of light: (a) Constant classical intensity produces photo-electrons with Poisson statistics; (b) Thermal light results in a compound
Poisson process with a Bose-Einstein distribution, and ‘bunching’ of the photo-electrons (J.C.Dainty)
Information content of light. IIIInformation content of light. III
D.Dravins, ESO Messenger No. 78, 9
Quantum effects in cosmic light
Quantum effects in cosmic light
Examples ofastrophysical
lasers
Early thoughts about lasers in space
Early thoughts about lasers in space
D. Menzel : Physical Processes in Gaseous Nebulae. I , ApJ 85, 330 (1937)
J. TalbotLaser Action in Recombining PlasmasM.Sc. thesis, University of Ottawa (1995)
Quantum effects in cosmic light
Quantum effects in cosmic light
Hydrogen recombinationlasers & masersin MWC 349 A
Hydrogen recombination lasers & masers in MWC 349A
Circumstellar disk surrounding the hot star.Maser emissions occur in outer regions while lasers operate nearer to the central
star.
V. Strelnitski; M.R. Haas; H.A. Smith; E.F. Erickson; S.W. Colgan; D.J. HollenbachFar-Infrared Hydrogen Lasers in the Peculiar Star MWC 349A Science 272, 1459 (1996)
Quantum Optics & CosmologyQuantum Optics & Cosmology
The First Masersin the Universe…
M. Spaans & C.A. NormanHydrogen Recombination Line Masers at the Epochs of Recombination and ReionizationApJ 488, 27 (1997)
FIRSTMASERSIN THE
UNIVERSE
The black inner regiondenotes the evolutionof the universe before
decoupling.
Arrows indicate maseremission from the epoch
of recombination andreionization.
Quantum effects in cosmic light
Quantum effects in cosmic light
Emission-line lasersin Eta Carinae
Eta Carinae
HST
Visual magnitude
ESO VLT
Model of a compact gas condensation near η Car with its Strömgren boundarybetween photoionized (H II) and neutral (H I) regions
S. Johansson & V. S. LetokhovLaser Action in a Gas Condensation in the Vicinity of a Hot StarJETP Lett. 75, 495 (2002) = Pis’ma Zh.Eksp.Teor.Fiz. 75, 591 (2002)
S. Johansson & V.S. LetokhovAstrophysical lasers operating in optical Fe II lines in stellar ejecta of Eta CarinaeA&A 428, 497 (2004)
S. Johansson & V.S. LetokhovAstrophysical lasers operating in optical Fe II lines in stellar ejecta of Eta CarinaeA&A 428, 497 (2004)
S. Johansson & V.S. LetokhovAstrophysical lasers operating in optical Fe II lines in stellar ejecta of Eta CarinaeA&A 428, 497 (2004)
Quantum effects in cosmic light
Quantum effects in cosmic light
Laser effects inWolf-Rayet,
symbiotic stars,& novae
Sketch of the symbiotic star RW Hydrae
P. P. Sorokin & J. H. GlowniaLasers without inversion (LWI) in Space: A possible explanation for intense, narrow-band, emissions that dominate the visible and/or far-UV (FUV) spectra of certain astronomical objectsA&A 384, 350 (2002)
Raman scattered emission bands in the symbiotic star V1016 Cyg
H. M. SchmidIdentification of the emission bands at λλ 6830, 7088A&A 211, L31 (1989)
Quantum effects in cosmic light
Quantum effects in cosmic light
Emission fromneutron stars,
pulsars & magnetars
T.H. Hankins, J.S. Kern, J.C. Weatherall, J.A. EilekNanosecond radio bursts from strong plasma turbulence in the Crab pulsarNature 422, 141 (2003)
V.A. Soglasnov et al.Giant Pulses from PSR B1937+21 with Widths ≤ 15 Nanoseconds and Tb ≥ 5×1039 K, the Highest Brightness Temperature Observed in the Universe, ApJ 616, 439 (2004)
Longitudes of giantpulses comparedto the average
profile.Main pulse (top);
Interpulse (bottom)
A. Shearer, B. Stappers, P. O'Connor, A. Golden, R. Strom, M. Redfern, O. RyanEnhanced Optical Emission During Crab Giant Radio PulsesScience 301, 493 (2003)
Mean optical “giant” pulse (with error bars) superimposed on the average pulse
Coherent emission from magnetars
Coherent emission from magnetars
o Pulsar magnetospheres emit in radio;higher plasma density shifts magnetar emission to visual & IR (= optical emission in anomalous X-ray pulsars?)
o Photon arrival statistics (high brightness temperature bursts; episodic sparking events?). Timescales down to nanoseconds suggested (Eichler et al. 2002)
Quantum effects in cosmic light
Quantum effects in cosmic light
CO2 lasers onVenus, Mars & Earth
CO2 lasers on Mars
Spectra of Martian CO2 emission line as a function of frequency difference from line center (in MHz). Blue profile is the total emergent intensity in the absence of laser emission. Red profile
is Gaussian fit to laser emission line. Radiation is from a 1.7 arc second beam (half-power width) centered on Chryse Planitia. The emission peak is visible at resolutions R > 1,000,000.
(Mumma et al., 1981)
CO2 lasers on Earth
Vibrational energy states of CO2 and N2 associated with the natural 10.4 μm CO2 laserG.M. Shved, V. P. Ogibalov
Natural population inversion for the CO2 vibrational states in Earth's atmosphereJ. Atmos. Solar-Terrestrial Phys. 62, 993 (2000)
”Random-laser” emission”Random-laser” emission
D.Wiersma, Nature,406, 132 (2000)
Letokhov, V. S.Astrophysical LasersQuant. Electr. 32, 1065 (2002) = Kvant. Elektron. 32, 1065 (2002)
Masers and lasers in the active medium particle-density vs. dimension diagram
Quantum Optics @ TelescopesQuantum Optics @ Telescopes
Detectinglaser effects in
astronomical radiation
Intensity interferometryIntensity interferometry
Narrabri stellar intensity interferomer circa 1970 (R.Hanbury Brown, R.Q.Twiss et al., University of Sydney)
S.Johansson & V.S.LetokhovPossibility of Measuring the Width of Narrow Fe II Astrophysical Laser Lines in the Vicinity ofEta Carinae by means of Brown-Twiss-Townes Heterodyne Correlation Interferometryastro-ph/0501246, New Astron. 10, 361 (2005)
Spectral resolution = 100,000,000 !
Spectral resolution = 100,000,000 !
o To resolve narrow optical laser emission (Δν 10 MHz) requires spectral resolution λ/Δλ 100,000,000
o Achievable by photon-correlation (“self-beating”) spectroscopy ! Resolved at delay time Δt 100 ns
o Method assumes Gaussian (thermal) photon statistics
Photon statistics of laser emissionPhoton statistics of laser emission
• (a) IfIf the light is non-Gaussian, photon statistics will be closer to stable wave(such as in laboratory lasers)
• (b) IfIf the light has been randomized andis close to Gaussian (thermal), photon correlation spectroscopy will reveal the narrowness of the laser light emission
Photon correlation spectroscopyPhoton correlation spectroscopy
E.R.Pike, in R.A.Smith, ed. Very High Resolution Spectroscopy, p.51 (1976)
LENGTH,TIME &FREQUENCYFORTWO-MODESPECTRUM
Photon correlation spectroscopyPhoton correlation spectroscopy
o Analogous to spatial informationfrom intensity interferometry,photon correlation spectroscopydoes not reconstruct the shape of
the source spectrum, but “only” gives linewidth information
D. Dravins 1, C. Barbieri
2
V. Da Deppo 3, D. Faria
1, S. Fornasier 2
R. A. E. Fosbury 4, L. Lindegren
1
G. Naletto 3, R. Nilsson
1, T. Occhipinti 3
F. Tamburini
2, H. Uthas 1, L. Zampieri
5
(1) Lund Observatory(2) Dept. of Astronomy, Univ. of Padova
(3) Dept. of Information Engineering, Univ. of Padova(4) ST-ECF, ESO Garching
(5) Astronomical Observatory of Padova
HIGHEST TIME RESOLUTION, REACHING QUANTUM OPTICS
• Other instruments cover seconds and milliseconds
• QuantEYE will cover milli-, micro-, and nanoseconds, down to the quantum limit !
MILLI-, MICRO- & NANOSECONDS
• Millisecond pulsars ?• Variability near black holes ?• Surface convection on white dwarfs ?• Non-radial oscillations in neutron stars ?• Surface structures on neutron-stars ?• Photon bubbles in accretion flows ?• Free-electron lasers around magnetars ? • Astrophysical laser-line emission ?• Spectral resolutions reaching R = 100
million ?• Quantum statistics of photon arrival
times ?
John M. Blondin
(North Carolina State University)
Hydrodynamics on supercomputers:
Interacting Binary Stars
Photon Bubble
Oscillations in Accretion
Klein, Arons, Jernigan & Hsu ApJ 457, L85
(1996)
Fluctuations of Pulsar Emission
with Sub-Microsecond Time-Scales
J. Gil, ApSS 110, 293 (1985)
Rapid oscillations in neutron starsDetection with RHESSI of High-Frequency X-Ray Oscillations in the Tail of the 2004 Hyperflare from SGR 1806-20: Watts & Strohmayer, ApJ 637, L117
(2006)
Power spectra after mainflare (25–100 keV), atdifferent rotational phases:QPO visible at 92.5 Hz.
Possible identification:Toroidal vibration modeof neutron-star crust?
Rapid oscillations in neutron starsDetection with RHESSI of High-Frequency X-Ray Oscillations in the Tail of the 2004 Hyperflare from SGR 1806-20: Watts & Strohmayer, ApJ 637, L117
(2006)
Surface patterns for torsional modes that may have been excited by the hyperflare.Colors and arrows indicate the magnitude of the vibrations.
(Max Planck Institute for Astrophysics)
p-mode oscillating neutron starp-mode oscillating neutron star
1215Y
Non-radial oscillations in neutron starsMcDermott, Van Horn & Hansen, ApJ 325, 725 (1988)
Advantages of very large telescopes
Advantages of very large telescopes
Telescope diameter
Intensity <I> Second-order correlation <I2>
Fourth-order photon statistics <I4>
3.6 m 1 1 1
8.2 m 5 27 720
4 x 8.2 m 21 430 185,000
50 m 193 37,000 1,385,000,000
100 m 770 595,000 355,000,000,000
. . .