zhu, ming (on behalf of the fast team) national astronomical observatories
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FAST Project and its Science Goals. Five hundred meter Aperture Spherical radio Telescope. Zhu, Ming (on behalf of the FAST team) National Astronomical Observatories Chinese Academy of Sciences. 2012 April 2. content Introduction to the FAST project General technical specifications - PowerPoint PPT PresentationTRANSCRIPT
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Zhu, Ming (on behalf of the FAST team)National Astronomical Observatories
Chinese Academy of Sciences2012 April 2
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content
• Introduction to the FAST project
• General technical specifications
• Last Status
• FAST Science
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Unique Karst depression as the site
Active main reflectorCable - parallel robot feed support
Five hundred meter Aperture Spherical Telescope
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Guiyang
Site: the Karst region in south Guizhou Province
Site Surveying in Guizhou
Location: N25.647222º E106.85583°
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Quick Bird Fly Oct. 6, 2005
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排水隧道 1.2km
2012-03-28
FAST model construction process
1. tower
2. girder ring
3. cementdepression
4. cable & node
5. actuator
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2. General Technical Specification
Spherical reflector : Radius ~ 300m, Aperture ~ 500m,
Opening angle 110~120°
Illuminated aperture : Dill=300m
Focal ratio : f/D =0.467
Sky coverage : zenith angle 40°(up to 60°with efficiency loss)
tracking hours 0~6h
Frequency : 70M ~ 3 GHz ( up to 8GHz in future upgradin
g )Sensitivity (L-Band) : A/T~2000, T~20 K
Resolution (L-Band) : 2.9′
Multi-beam (L-Band) : 19, beam number of future FPA >100
Slewing : <10min
Pointing accuracy : 8″
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Sky coverage
ZA 30 deg
ZA 40 deg
ZA 60 deg
FAST Zenith
Sky coverage
FAST vs. Arecibo
ZA 56 deg
Opening angle - sky coverage
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In layout 2000
0.327 5
HI surveying
EoR
Pulsar
VLBI
17 Lines
SETI
30.13 1.42
z~20
OH(4) H2CO(6)
Water hole
Space scienceS Band X Band
First phase Second phase
(GHz)8
70MHz
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HCOOH
CH3OH HC5N(4) CH(4) CH4
300MHz 5.2GHz
Frequency range
C Band
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Site
Active Reflector
Feed support
Measurements
Receivers
Observatory
Site
Exploration
Drainage
Earth work
Active Reflector
Disaster prevention
Main cable net
Elements
Winches
Tension monitoring
Tower
Capstan
AB-rotator & Stewart
Cables
Mark stone
Laser total station
Photogrammetry
Field bus
Optical fiber
Observatory building
Computing center
Observatory
Feed support
MeasurementsReceivers
Receivers
Backend
3.Technical plan– critical technology
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Structure of active reflector 500m girder built around hills supported by 50 pillars Backup consists of ~7000 steel strands actuated by ~2300 down tied cables driven by winches anchored into ground Errors 5.0 mm r.m.s in total
地锚背架结构 主索网
周边支承结构下拉索 索节点主索网
Feed support Three main parts of cabin suspension Cable network - adjustable system Stewart Platform - secondary adjustable system Close loop control
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Dynamic experiment on Stewart stabilizer, Sept. 2002
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Measurement – precise, quick and in long distance
Task 1: 3-D spatial positions of focus cabin Large working range up to 300 m Errors ~1 mm Sampling rate > 10 Hz
Task 2: profiles of main reflector
Number of targets ~2400 ~1000 in illuminated area Accuracy 1~2mm Sampling interval 10 sec ~ few min
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CCD : 20Hz ; 0.5cmDGPS : 10Hz ; 1cm
Laser Tracker : 1KHz ;0.05mm
IMU : 0.1
Measuring Total station
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PhotogrammetrySurveying reflector profile
1000 nodes within
illuminated area
to be scanned in real-time
period ~ 1 min
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MainControl Computer
Feed Control Computer
Reflector Control Computer
Power Monitoring
Location Reference
Time Reference
Laser Measurement
Cable Tension Measurement
Inertial Measurement
Reflector Measurement
Cable Tension Measurement
Main Control Diagram
class CORBA通知服务的结构
Notification ChannelSupplier
+ SetData()
CosNotifyComm::StructuredPushSupplier
CosNotifyComm::StructuredPushConsumer
Consumer
+ push_structured_event()
Helper
+ getChannelDomain()+ getChannelKind()+ resolveNamingService()+ resolveNotifyChannel()
CORBA Notification Service
Supplier Child
+ SetData()
Consumer Child
+ push_structured_event()User defined classes
User defined classes
federate push
push datacreate
connect
+Consumerpush data+Supplier
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Receiver layout design (2000 & 2006)
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ReceiverDiagnostics
Feed
+ polarizerLNA Mixer E/O
HI
line
Pu
lsar
VL
BI
SE
TI
mu
lti
O/E
Receiver -- Schematic Diagram
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L-band Multi-beam receivers and its prototyping
y
x
z
接收机与终端接收机与终端 - 2- 2密云模型观测情况
EMI测试
密云模型低频馈源
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No Band (GHz) Beams Pol. CryoTsys(K)
Science
1 0.07 – 0.14 1 RCP LCP
no1000
High-z HI(EoR),PSR, VLBI, Lines
2 0.14 – 0.28 1 RCP LCP
no400
High-z HI(EoR),PSR, VLBI, Lines
3 0.28 – 0.56 1 or multi RCP LCP
no150
High-z HI(EoR),PSR, VLBI, LinesSpace weather, Low frequency DSN
4 0.56 – 1.02 1 or multi RCP LCP
yes60
High-z HI(EoR),PSR, VLBI, LinesExo-planet science
5 0.320 – 0.334 1 RCP LCP
no200
HI,PSR,VLBIEarly sciences
6 0.55 – 0.64 1 RCP LCP
yes60
HI,PSR,VLBIEarly Sciences
7 1.15 – 1.72 1 L wide RCP LCP
yes25
HI,PSR,VLBI,SETI,Lines
8 1.23 – 1.53 19 Lnarrow multibeam
RCP LCP
yes25
HI and PSR survey, Transients
9 2.00 – 3.00 1 RCP/LCP
yes25
PTA, DSN, VLBI, SETI
9 sets of FAST receivers NAOC - JBO
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HI was observed using 50m model in Sept 2006.
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FAST sciences
• Neutral Hydrogen line (HI) survey
• Pulsar research
• VLBI network
• Molecular line study (including
recombination lines, masers)
• Search for Extraterrestrial Intelligence
(SETI)
FAST all-sky HI survey• Using a 19 beam L-band receiver to map 2.3π sterradians
FAST sky at 40 sec per beam, doable in 1-2 yrs.– Expect about 1 million detections (Duffy et al. 2008) with MHI< 1011
Mout to z ~ 0.15 in a range of environments including Coma, Hydra, Ursa Major, Persues-Pisces supercluster plus neighboring voids.
• Large HI database for T-F relation, peculiar velocity study of the local universe with a larger volume.
• Extend ALFALFA Sky coverage
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Duffy et al (2008)
Number of galaxies to
be detected per day
(18h) using FAST 19
beams with different
integration time
---- 6 sec
---- 60 sec
---- 600 sec
---- 6000 sec
---- 60000 sec
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Xuelei Chen Veff vs scale ¼ sky coverage survey by FAST ---- 6 s 44 days---- 12 s 88 days----1 min 440 days
Duffy et al Spectra errors
Deep mapping of Nearby Galaxies
• To map a 4 square degree area, with an integration time of 10 minute per beam, in 10 hours we can reach a 3σ sensitivity of 1.5 x1017 cm-2 per 2.1 km/s channel.
• Select regions of different environments, – void, big galaxies, clusters …
Kacprzak et al. 2010
ΛCDM COSMOLOGICAL GALAXY SIMULATIONS
How is gas accreted from the IGM onto galaxies?
• low NHI gas seen around M 31 and M 33
Braun &Thilker 2004
Prochaska et al. 2010
WALLABY: NHI~2x10^19 cm-2DINGO deep: NHI~2.6x 10^18 cm-2DINGO u-deep:NHI~1.2x10^18 cm-2
FAST
HI map of M31
Braun & Thilker 2003
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Kravtsov - Simulation on dark matter distribution in a normal galaxy
Xuelei Chen – Estimated FAST detection sensitivity of 1 min & 1 h Line width 30km/s,S/N -10
Searching for High Z HI and OH Megamaser
FAST0.1 < z < 5 0◦ < < 70◦Smin ~0.1 mJy
~ 3000 OHM
Arecibo0.1 < z < 0.45 0◦ < < 37◦Smin ~0.6 mJy
53 OHMN
2
min)1(~ zSN
The simulated uv-coverage of EVN+FAST for sources of Declination 10 and 60 degree
Search for binary SMBH
• Galaxy mergers yield inspiraling, binary, and recoiling black holes that may be detectable with high resolution VLBI search for off-nuclear and binary SMBHs
• FAST+VLBI
Summary
•FAST has very high sensitivity and large coverage of the northern sky•Good for searching for weak signals, low surface brightness structures•FAST has the potential to make great contributions to HI and pulsar studies and VLBI observations
• First light expected in 2016
Website: fast.bao.ac.cn