Diapositiva 1

1
Some thoughts on the astronomical time domain
and related issues with (m ?)satellites

• Giuseppe LongoSalvatore CapozzielloMaurizio
  PaolilloEster PiedipalumboGiovanni dAngelo et
  al
• Dipartimento di Scienze Fisiche Università
  Federico II di Napoli
• INFN Sezione di Napoli INAF Sezione di
  Napoli
• Also from talks with C. Barbieri (INAF)

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What makes un(less)expensive a satellite
No steering (no pointing capabilities) Small
weight and size (hence Small field of
view) Limited scope (non multi-purpose) Must
require little amount of technological
development
3
Astronomical parameter space
Flux
Non-EM
Morphology / Surf.Br.
Time
Wavelength
?
Polarization
Proper motion
Dec
RA
What is the coverage? Where are the gaps? Where
do we go next? Why are space observations needed?
( G.S. Djorgovski Caltech)
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Parameters defining the TIME DOMAIN at a given l

• Time coverage Tcov(start/end of observations
• Sampling (Dt)(average interval between two
  subsequent observations
• Integration (Tint)exposure time of typical data
  taking

Defines aliasing (maximum lenght of detectable
variations)
Defines sparseness of events and accuracy of
period reconstruction
Defines minimum time scale of events
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TYPES OF DATA A SIMPLE VIEW
Large f.o.v Surveys
6
Time domain is big business in the
optical Whole sky POSS I II, SDSS, UKIRT,
etc. (optical, NIR, Palomar QUEST and
Palomar NEAT LSST (USA) Finalized OGLE,
MACHO, SLOTT-AGAPE (optical) Solar system
patrols (optical) Supernovae searches
(optical) GRB monitoring (optical and
other) AGN monitoring (radio, little optical)
limited wavelenght coverage fairly deep poor and
uneven sampling long time baseline (months/years)
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What do you find in surveys? (months to hours
time scales INAF domain)

• Mainly serendipitous discovery of new phenomena
• Better understanding of old phenomena(SN,
  distance scale, deceleration, etc.)
• Statistically significant samples (NEAR,
  asteroids, Kuiper belt, etc up to clusters)
• Better characterization of some physical
  parameters
• Might lead to some exciting new physics (cf.
  Amendola) but

8

• What do you find in pointed observations?(months
  to hours time scales INAF domain)
• Monitoring campaigns lead to variability (from
  short to long term) studies for selected objects
• Possible periodic behaviors
• Correlations among variations at different
  wavelenghts

Periodic light curve of Blazar (binary black
hole) Ciaramella et al. 2004
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INAF domain
INFN domain
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The seconds to milliseconds domain
Kilohertz quasiperiodic oscillations in Sco X-1,
(Miller, Strohmayer, Zhang van der Klis,
RXTE)
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milliseconds to m-seconds

• Tidally-driven transport in accretion disks in
  close binary systems (J. M. Blondin,
  Hydrodynamics on supercomputers Interacting
  Binary Stars)
• Photon Bubble Oscillations in Accretion, Klein,
  Arons, Jernigan Hsu ApJ 457, L85 (1996)GRO
  J1744228 presents quasi-periodic oscillations
  (QPOs) of intensities in the energy band 312 keV
• Non radial oscillations in neutron stars, Mc
  Dermott, Van Horn Hansen, ApJ 325, 725
  (1988)
• Fluctuations of Pulsar Emission with
  Sub-Microsecond Time-Scales, J. Gil, ApSS 110,
  293 (1985)
• etc

12
The nanoseconds domain

• Nanosecond radio bursts from strong plasma
  turbulence in the Crab pulsar, Hankins, Kern,
  Weatherhill Eilek, Nature 422, 141 (2003)

13
Nanoseconds astrophysics is already ongoing
within INFN
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A POSSIBLE EXPERIMENT (which could be possibly
done with a very low cost satellite using
existing INFN/INAF know-how)
Measuring the time delay of multiple QSO images
with second accuracy
15
Quasars time delay from multiple images
T depends on cosmology F depends on the lens
mass model

• Additional benefits
• Detailed structure and mass model of the lens
  through microturbulence
• High spatial resolution study of the QSO structure

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Why are X-rays important ?
17

• In the assumption that we can measure
  polarization of individual photons
• There are mechanisms which entangle photons (ask
  Capozziello ) but also on non entangled photons
  works with slightly lower accuracy using light
  curve shapes

• Angular resolution is not an issue !
  (overlapping sequences present a trivial problem
  of crittography)
• Contamination from non entangled photons may be
  tackled (simulations are needed)