ESTREMOWFXRT GRB as cosmological probes

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ESTREMO/WFXRTGRB as cosmological probes
Luigi PiroIASF-INAF, Rome
?
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WHIM WG (in absorption)
GRB WG
Lorenzo Amati Alessandra Galli Bruce
Gendre Luigi Piro G. Ghirlanda S. Campana

• Enzo Branchini
• Alessandra Corsi
• Fabrizio Nicastro
• Luigi Piro
• Matteo Viel

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The Early Universe and its evolution to present
ages

• Tracing cosmic history back to and beyond the
  time when the first objects ignited, ending the
  dark era of the Universe.
• The interplay (feedback) from star-size up to
  the largest structures in the Universe is an
  important element of the evolution.
• X-ray observations planned by this mission
  provide a privileged and unique information in
  this respect, by relying on two cosmological
  probes large scale X-ray structures and
  Gamma-Ray Bursts.

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The Evolution of large scale structures

• Most of the mass of our Universe visible only
  in X-rays - resides in large scale structures,
  distributed in a filamentary network shaped by
  the gravitational pull of the dark matter and
  whose evolution depends also on dark energy EOS.
  Clusters of galaxies are in the centers of this
  cosmic network.
• characterize the physical, dynamical and
  chemical structure from cluster core to the
  outskirt.
• evolution of physical and chemical properties of
  clusters from the present to their formation
  epoch
• study the interface (i.e. density, metal
  enrichment) between the cluster outskirt and the
  WHIM
• determine the main physical and chemical
  parameters of WHIM (density, temperature,
  ionization, abundances) through absorption (via
  GRB) and emission measurements
• dark energy Particularly exciting is the use of
  cluster surveys to determine the dark energy
  parameters. This is to be derived sorting out the
  systematics in the self-calibration process,
  possibly taking advantage of total
  mass-luminosity-temperature relationship directly
  derived for a subsample of clusters.

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The evolution GRBs as cosmological beacons

•  Gamma-Ray Bursts as beacons to
• pinpoint the formation of first population of
  luminous sources ignited in the dark Universe
  (zgt7)
• measuring the cosmic history of metals in star
  forming regions
• probing the WHIM properties through high
  resolution absorption studies.
• Derive the luminosity-redshift relation of GRB as
  clues to the nature of the Dark Energy

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GRB The brightest and most distant sources
E(iso) up to 1053-1054 erg in few seconds
Observing a mid-bright GRB afterglow with a fast
(min.) pointing with 2000 cm2 telescope yields
106 X-ray photons, and 103 cts in 1 eV
resolution bin
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X-ray afterglow fluence distribution comparing
methods 1-2a/b
F. Fiore, first Rome meeting
1000 GRB yr-1
Using the mean value for the ratio prompt X-ray
fluence / X-ray afterglow flux _at_ 11 hrs and the
WFC logN-logS, we can compute the number of
bursts per yr observable with a FOV of 3sr
100 sec
ESTREMO/WFXRT Meeting on scientific requirements
Bologna, 2006 May 4-5
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X-ray absorption in the GRB local environment

• X-ray absorption column densities in the
  afterglow NH1021-22 cm-2 (Stratta et al 2000,
  Campana et al 2006)
• Consistent with NH in Giant Molecular clouds

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GRB Tomography of the Universe I

• Map the metal evolution vs z

Simulation of X-ray edges produced by metals (Si,
S, Ar, Fe) by a medium with column density NH5
1022 cm-2 with 1/10 and solar-like abundances in
the environs of a bright GRB at z5., as observed
ESTREMO/WFXRT (1min to 60 ksec)
X-ray redshift !
Ar
S
Fe
Si
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The Early Universe and its evolution to present
ages

• ESTREMO/WFXRT will use two different cosmological
  probes  Gamma-Ray Burts and large scale
  structures (Clusters of Galaxies and the cosmic
  network) to address this challenging goal by
  observing
• The X-ray cosmic web, filaments (WHIM Warm Hot
  Intragalactic Medium) of gas accreting onto Dark
  Matter structures.
• Outskirts of clusters (where most of the yet
  unobserved cluster mass is residing) (Talk by S.
  Molendi)
• Cluster surveys to constrain  Dark Energy. (Talk
  by S. Molendi)
•  Gamma-Ray Bursts as beacons to
• pinpoint the formation of first population of
  luminous sources ignited in the dark Universe
  (zgt7)
• measuring the cosmic history of metals in star
  forming regions
• probing the WHIM properties through high
  resolution absorption studies.
• Derive the luminosity-redshift relation of GRB as
  clues to the nature of the Dark Energy

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Tomography of the Universe with GRBs the Cosmic
Web

• 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
• From models most of the baryons in the loca
  (zlt1-2) Universe in hot or warm filamentary
  structures heated by the gravitational pull of DM
  

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X-ray afterglow fluence distribution comparing
methods 1-2a/b
F. Fiore, first Rome meeting
1000 GRB yr-1
Using the mean value for the ratio prompt X-ray
fluence / X-ray afterglow flux _at_ 11 hrs and the
WFC logN-logS, we can compute the number of
bursts per yr observable with a FOV of 3sr
100 sec
ESTREMO/WFXRT Meeting on scientific requirements
Bologna, 2006 May 4-5
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Random Systematic Errors

• Reducing ?b and dN/dz uncertainties
• from current (140,-70) .
• -10 detections would reduce random errors to 20
  level.
• -100 detections would bring relative errors down
  to a
• few level.

Fiore. ESTREMO/WFXRT meeting. Rome 01/06
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RandomSystematic Errors
WHIM models rely on several assumptions (e.g. IGM
metallicity, the ionization state of the various
metals etc) that may result in systematic errors
when comparing model and observations.
Fang et al 2002
Cen et al. 2005
Large scatter in dg(d) T(d) Z(d) relations does
not allow a precise estimate of cosmological
parameters (apart from Wb)
Cen et al. 2002
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Detecting WHIM filaments in Absorption
N.of GRBs and WHIM filaments in 3 yrs (based on
Cen05)
6 GRB, 60 filaments
60 GRB, 360 filaments
300 GRB, 600 filaments
500-1000 WHIM filaments detected in absorption
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Synthetic Absorption Spectra Hydro-model
(Borgani, Viel, et al)
Metallicity
Temperature
Density
OVII Density
OVIII Density
Redshift Slice z0.45,0.514
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Synthetic Absorption Spectra Hydro-model

• Hydro simulation (Viel 2006) Stacking outputs _at_
  z0.0/0.1/0.2/0.3/0.4/0.5 Box 60 Mpc/h. 4003 DM
  4003 GAS Softening 2.5 Kpc/h comoving. Star
  formation. No Feedback. UV background (QSO
  galaxies). No X-ray background. No Radiative
  transport. No metal cooling. 7 independent line
  of sights out to z0.5. T, r, Z as a function of
  redshift. OVI, OVII, OVII Kb, OVIII, CV, NeIX,
  MgXI, FeXVII optical depth

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Lines with EW gt 0.08 eV Preliminary
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The Early Universe and its evolution to present
ages

• ESTREMO/WFXRT will use two different cosmological
  probes  Gamma-Ray Burts and large scale
  structures (Clusters of Galaxies and the cosmic
  network) to address this challenging goal by
  observing
• The X-ray cosmic web, filaments (WHIM Warm Hot
  Intragalactic Medium) of gas accreting onto Dark
  Matter structures in emission
• Outskirts of clusters (where most of the yet
  unobserved cluster mass is residing)
• Cluster surveys to constrain  Dark Energy.
•  Gamma-Ray Bursts as beacons to
• pinpoint the formation of first population of
  luminous sources ignited in the dark Universe
  (zgt7)
• measuring the cosmic history of metals in star
  forming regions
• probing the WHIM properties through high
  resolution absorption studies.
• Derive the luminosity-redshift relation of GRB as
  clues to the nature of the Dark Energy

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Requirements for NFI-TES

• Energy range from 0.1 to 3 kev (7 keV goal)
• Area 1500cm2 _at_1keV (assuming filter
  efficiency50)
• Energy resolution 2 eV below 1 keV (goal 1 eV),
  3-4 eV at 6 keV
• Number of imaging pixels 400 (requirement)
  1000 (goal)
• Size of pixel (depending on the plate scale)
  200-500 um
• Field of view for GRBs the requirement is that
  the FOV of the central TES chip be larger than
  the WFM localization error (3)
• 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 2 arcmin, and
  a pixel size of 250 um, the count rate per pixel
  would be about 300 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 (for a FL4m).

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TES configuration
goal
Central pixel size 0.3 (f4m) 33 pixels in
HPD2 0.6 (f2m) 8 pixels For 100u pixel 32
pixels in the HPD
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TES configuration
requirement
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Requirements for WFMonitor from GRB for WHIM in
absorption

• The main requirement is to measure at least one
  absorption line in about 100-500 filaments in 3
  years and to measure at least 2 or more lines (to
  constrain the physical and chemical status) in at
  least 30 (TBC) of the filaments
• Requirement on prompt flux The strongest
  absorption line expected in a whim filament has
  an EW of at most 0.2 eV. Taking into account the
  NFI performances (1500cm2, fast reaction,De2eV
  requirement, 1ev goal) this requires a fluence in
  the afterglow greater than about 1e-6 erg cm-2.
  This translates in a 2-10 keV PROMPT flux of
  about 1-3 Crab. In other terms GRB fainter than
  this will not yield any significant detection of
  WHIM absorption lines
• Requirement on field of view taking into account
  the logN log S distribution of GRB, the minimum
  fov (in order to have 500 detected filaments) is
  4 steradiants

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(Very) Minimum (baseline) requirements for WFI

• From the above, requirements for the localizator
  are
• Flux rather bright events (gt1 Crab)
• Energy range need to go down to at least 4 keV.
  Upper range not a driver for localization (but
  see below), 40 keV should be good enough.
• FOV gt 3-4 sr (6sr goal)
• Localization (driven by NFI) better than 3arcmin
• Need to have at least the temporal signature in
  the hard X-ray range (gt100 keV) to identify a
  GRB