Luigi Piro IASF-INAF Rome

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Luigi PiroIASF-INAFRome
Workshop on WHIM and mission opportunities
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Workshop on WHIM and mission opportunities

• Scope of the meeting
• Take into account present (WHIM) mission
  profiles and related technology
• Discuss the status of the art in WHIM
  observations and theory and translate it in
• Derive requirements (organize a wg) to improve
  present profiles
• Discuss next steps and actions finilized to carry
  out a joint programme

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Where are the baryons at zlt2 gone?

• Detailed calculation from Big Bang
  Nucleosynthesis indicate 0.02 lt h2Ob lt 0.06
• At z 3-4 the observations are in agreement Lya
  forest
• At z0 the baryon in stellar systems, neutral
  Hydrogen, X-ray emitting gas in cluster of
  galaxies is one order of magnitude less than the
  predictions.
• Where have the baryons gone?
• From models 50 of baryons in hot or warm
  ionized IGM
• In the current models at zgt2 the gas is diffuse.
  At zlt2 large potential wells are produced and the
  gas is shock-heated.
• The gas is trapped in filaments by the
  gravitational pull of DM

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Experiments / missions for WHIM

• IMXS-IMBOSS (I-USA), MBE (USA)
• New proposals ESTREMO (I), DIOS (J), NEW(H),
  Pharos (USA)
• Large interest from international community (but
  so far not successful, to be discussed tomorrow)
• Italy WHIM science key interest not only of
  astrophysical community but also of INFN (dark
  matter). IMXS-IMBOSS large field / high
  resolution spectroscopy survey.

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WHIM mission concepts
DIOS NEW ESTREMO MBE PHAROS
WHIM Emiss. Emiss. Abs. Abs. Emiss. Emiss. Abs.
Mitsuda, WHIM ws 2005
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• Italy WHIM science key interest not only of
  astrophysical community but also of INFN (dark
  matter, S. Vitale).
• IMXS-IMBOSS large field (1sr) / high
  resolution (6 eV) spectroscopy survey of the sky.
  Grasp (AW 2000 cm2 deg2). Feasibility
  assessment for allocation to ISS carried out.
  Activities stopped in 2002 given the ISS
  situation

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ESTREMOExtreme phySics in Transient and Evolving
cosMos The first observatory with very high
resolution X-raySpectroscopy, Polarimetry and
Fast repointing
?
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History

• The concept of Next Generation GRB Observatory
  (NG-GRBO) born in a meeting on EXIST in 2000 in
  US
• Sister satellite led by European partners to
  perform very fast ( 1 min) follow-up observations
  of GRB transients localized by EXIST X-ray
  cosmology wityh GRB
• Included as mission concept for a Italian mission
  in the proposal to ASI 2003
• Evolved and expanded following two meetings in
  2003 in Rome (with participants from Mi, Bo,
  Pa), in the Netherlands (SRON), and Turin with
  Alenia Spazio (pre-feasibility assessment of
  spacecraft fast slewing capabilities)
• NEW derivation from SRON. Potential merging with
  NEW and DIOS (workshop in Japan, 2005)

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Scientific drivers

• Evolution of cosmological structures and sources
  in the Universe X-Ray Cosmology GRB as beacons,
  WHIM and dark matter, formation of first
  structures in the Universe
• Extreme physics (e.g. test of general relativity
  in Black Holes, GRB engines and progenitors)

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New X-ray cosmology with GRB

• Identify high-z GRB and their primordial host
  galaxies
• Study the evolution of metals star formation
  with z
• WHIM dark matter
• Dark energy and extension of SN results at zgt1

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GRB as cosmological probes

• Map the metal evolution vs z

Simulations of X-ray edges produced by metals
(Si, S, Ar, Fe) by a medium with column density
NH5 1022 cm-2 and solar-like abundances in the
host galaxy of a bright GRB at z5., as observed
ESTREMO with an observation starting 60 s after
the main pulse and lasting 60 ksec
Ar
S
Fe
Si
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Mission profile

•  
• The mission is based on the combination of a
  wide field instrument, a narrow field instrument
  and fast pointing, i.e.
•         Fast (lt1 min) follow-up observations
  with
•         High resolution X-ray spectroscopy
  (De2-4 eV in the 0.1-10 keV range) and
•         High sensitivity X-ray polarimetry
  devices
•         of independently localized X-ray
  transient phenomena in the sky with a wide field
  monitor in the X/hard-X range.
•  
• Each one is the state of the art in the field and
  the combination provides a unique and
  unprecedented capability.

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WFC
TEScryo-system
Polarimeter
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Scientific goals

• Estreme objects in our Universe characterized by
  very large energy release over short time scale
  (minutes-hours) Gamma-ray Bursts, Massive Black
  Holes, Neutron stars, Supernovae explosions,
  Flare stars
• Evolution of the Universe the new X-ray
  cosmology by using the brightest and most distant
  explosions, the Gamma-Ray Bursts

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GRB (afterglows ) as bright background source for
WHIM absorption studies

• (Piro et al, ApJ 05)

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WHIM absorption lines towards GRB afterglows
Fraction of the total fluence of the afterglow of
a GRB in the interval t060 s and t, for a decay
power law with slope 1.3
Similar numbers from SWIFT Corsis talk
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Dark matter WHIM X-ray forest
Structure simulation from Cen Ostriker (1999)
?
Simulations of WHIM absorption features from OVII
as expected from filaments (at different z, with
EW0.2-0.5 eV) in the l.o.s. toward a GRB with
Fluence4 10-6 as observed with ESTREMO (in 100
ksec). About 10 of GRB (10 events per year per 3
sr) with 4 million counts in the TES focal plane
detector
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Comparison of main parameters for WHIM absorption
line detection at 0.5 kev for this and present
and future missions
The relative fluence S/S0 of the afterglow is
derived assuming a decay slope of 1.3, with an
integration of about 100 ksec, starting at 60s
for this missions and at 11 hrs for the other
missions. M is the factor of merit Aeffh S/DE
for line detection EWmin Ks /k?M, when Ks is
the number of s required for the detection (Ks5)
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WHIM in absorption and emission

• Focal lenght 4 m, (1.2 per mm), with pixel
  500um, and radial geometry would give radius of
  about 10 for 1000 pixels (4.5 for 200 pixels)
• Possibility to study the same WHIM filament first
  in absorption and then, when the GRB afterglow
  has disappeared, in emission

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WHIM emission lines detection some estimates

• Filament completely filling the FOV NL ? (Aeff)
  x (FOV) x T
• The contribution of photons from XRB and
  Galactic emission is determined by the energy
  resolution ?E Nc ? ?E x (Aeff) x (FOV) x T
• S/N NL/Nc0.5 ? ((Aeff) x (FOV) x T) / ?E
  0.5 a larger Aeff x FOV increases the number
  of counts for a given integration time, but a
  higher energy resolution gives a better S/N.

Aeff x FOV (deg2cm2) ?E (eV) S/SXMM S/N/S/NXMM
XMM(pn) 230 60 1 1
Chandra 23 100 0.1 0.24
XEUS 8.3 (210) 1 (50) 0.04 (0.9) 1.5 (1.0)
Con-X 12 2 0.05 1.3
DIOS 55 2 0.2 2.7
ESTREMO 50 2 0.2 3.0
NEW 500 2 2 8.1
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Baseline Requirements (I)

• Wide-field monitor Localization and study of
  GRB X-Ray transients
• 2-300 keV 2-3 arcmin resolution solid angle gt 2
  sr such that gt50-100 GRB per year and a similar
  number of transient sources)
• Detector Technologies CdZnTe, Si, Lobster
• Small omnidirectional spectrometer for GRB
  spectrum (Epeak)

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Baseline Requirements (II)

• Autonomous fast follow-up 10-100 seconds
  following the transient position from on-board
  x-ray localizator (ala SWIFT)
• 1.5 ton class in low earth orbit (VEGA launcher,
  Malindi ground station)
• Launch in the 2012 frame
• - X-ray optics of 1000 cm2 eff.area (8xSWIFT)
• TES microcalorimeters (DE2 eV at 1 keV) AND KHz
  count rate (to observe Crab-like sources!!)
• For a typical X-ray afteglow, about 100.000 cts
  will be secured starting from 50 sec
• X-ray polarimeter with MDP 5 for Crab-like

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Requirements for NFI-TES

• Energy range from 0.1 to 10 keV
• Energy resolution 2 eV below 1 keV (goal 1 eV),
  around 3-4 eV at 6 keV
• Number of imaging pixels gt100, with a goal of
  1000
• Size of pixel (depending on the plate scale)
  200-500 um
• Field of view (assuming a 4 meter focal length, a
  500 u pixel and radial geometry) 8 arcmin
  diameter for 200 pixels, 18 arcmin diameter for
  1000 pixels
• Count rate vs flux conversion for a power law
  with photon index2 and Nh2e20 cm-2, 1 mCrab
  source would give about 10 cts/s in the 0.1-5 keV
  range. 
• Maximum count rate high enough to allow
  spectral measurements of a Crab-like source,
  corresponding to about 20.000 cts/s (for a
  low-energy absorption of 2e20 cm-2). Assuming a
  PSF with Half Energy Width of about 1 arcmin, and
  a pixel size of 250 um, the count rate per pixel
  would be about 400 cts/s, compatible with TES
  performance. The trade-off of pixel-size vs
  field of view is optimized with a detector in
  which the central part has pixels of 250 um
  size, and the outer region (devoted to background
  and WHIM emission line detection) has 500um pixel
  size.

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Spacecraft, launcher and Orbit

• Time to to slew to 60 degrees 20 sec
• 3-axis stabilized, Pointing accuracy 1
• Post facto attititude reconstruction lt20
• Zone of sun avoidance TBD
• Orbit LEO preferred for lower bkg and payload
  mass, but HEO is not ruled out
• Launch mass 1500 kg
• P/L mass 600 kg
• P/L power 800 W
• on-board memory upto 250 Gb
• downlink in S and X bands upto 512 kbps and
  210Mbps respectively during the passage
• compatible with VEGA Soyuz, Delta and other
  launchers,

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VEGA launch capability
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Allocation in VEGA
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New developments

• Merit of present configuration (extension to the
  7 kev range Fe line, polarimetry). WHIM in
  emission and absorption
• Increase the fov good for whim emission,
  (grasp), relax somewhat requirements on wfm .
  Price to pay Egt3 keV, complexity of TES central
  part (need smaller pixels to avoid pile up).