Presentazione di PowerPoint

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REM, Rapid Eye Mount, a Fast Slewing Robotized
Telescope to monitor GRB prompt afterglows
F.M.Zerbi, (on behalf of the REM Team)
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What is REM

• A fast moving telescope
• Alt-az 60 cm f/8 RC silver-coated
• 2 Nasmyth foci (one idle)
• 60 deg 5 sec to any ?,? in 60 sec

• with a high throughput NIR Camera
• 10x10 am2 FoV
• 1.2 as pixel scale (diff.limited)
• 0.9-2.3 microns (Z,J,H,Ks)
• 512x512 HgCdTe chip _at_77 Kelvin
• Wobbling plate for dithering

• and a Visible Imaging-Spectrograph
• 10x10 am2 FoV
• 0.55 as pixel scale
• 30 bins between 0.45-0.9 microns
• 1024x1024 Marconi CCD in Apogee head

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REM Scope
REM is conceived as a link between transient
phenomena detected at high energy from space
AND Large ground-based facilities on the ground
? Gamma Ray Bursts
Such a link is needed for - Transient Coordinate
determination
High Energy detections have large error-boxes
- Pre-screen of transient characterisitics
Cases selection for further observations
In both Cases crucial are a) Coverage up to
NIR b) Fast response
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Who Triggers REM ?
SWIFT
HETE II - WXM Wide Field X-ray Monitor lt10
arcmin errorbox - SXC Soft X-ray
camera. 30 arcsec errorbox

• What SWIFT gives us is
• Position of the GRB - 15 sec (4 am)
• Position of the XT 20-70 sec (5 as)
• Position of the OT 20-70 sec (n/10 as) (if
  there)
• Color Information 0.15-0.65 ?m600 sec

INTEGRAL - IBIS Cadmium/Telluride Coesium/Iodine
Imager FOV 9x9 deg and
precision 1 arcmin. - JEM-X X-ray
monitor FOV 4.8x4.8 deg and
precision 30 arcsec.
AGILE - GRID 5-20 arcmin precision (depends on
L) - Super-AGILE lt 4-5 arcmin precision.

• What SWIFT does not give us
• Position of the Red-T (above 0.65 ?m) and NIR-T

gt300 trigger per year !
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Primary Target ? GRB
50 of the known GRB do not show an Optical AG.
It could be dust
or it could be Ly-? if the GRB is high-z

• IF dust, K is much less
• absorbed more chance
• to get ?,? AND have
• info on dust via Col/Col
• diagrams

• IF Ly-?, we get ?,?
• when still bright enough
• to send trigger to large
• T-scopes to collect
• a spectrum at z14 !!

?Fast NIR?

• Dust should be destroyed
• by burst. IR photons
• penetrate while Higher
• energy photons do the job

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Why an Optical Spectrograph
ROSS will acquire 30 simultaneous calibrated data
points between 0.45 and 0.9 microns
This will allow to

• Correlate the time of the optical peaks with
• the distribution of Lorentz Factors in the
• original cataclysm.

• Detect the possible time dependent obscuration
• of optical transients associated with GRBs.

• Possibly detect the peak energy that goes from
• gamma to optical within few hours.

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Broad Band Coverage
Everybody (more or less) accept Synchrotron for
afterglow emission, based on late (1-12 d)
observations
What happens at the beginning ? Comptonization
dominates ?
Prompt Broad Band Spectrum and its variations in
time can tell us
Burst at different z observed at the same
wavelength can not be compared
Multi-band systematic observing allows a
comparison (at the same comoving freq.). The
larger the spectral baseline the larger the
z-range.
With REM we can compare z1 and z10
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IDLE Time
Any possible optimization of the Space-borne
trigger source will let free REM observing
time INTEGRAL-AGILE few bursts SWIFT-HETE II
more bursts but latitude/longitude
constraints

• Housekeeping and calibration
• Other Observing programs

Anywhere Rapid multi-frequency observations are
needed

• Multifrequency monitoring of AGNs
• Black Hole Candidates X-ray Novae
• Flare Stars

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REM Assembly

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REM Telescope
Ordered to
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REM Camera
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REM Camera
Diffraction limited
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ROSS Spectrograph
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ROSS Spectrograph
..Diffraction Limited
.. Constant Spectral Resolution
(AMICI)
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Who is REM
850,000
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The REM team
Science Team Primary G.Ghisellini Secondary
M.Rodonò S.Campana A. Fernandez-Soto F.Fiore G.Gen
tile G.Israel B.McBreen S.Messina E.J.A.Meurs E.Pa
lazzi (Ross Co-S) J.Paul P.Saracco L.Stella G.Tagl
iaferri C.Akerlof L.Amati J.Danzinger F.Frontera M
.Orlandini M.Tavani
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REM Location