status of lamost
DESCRIPTION
Status of LAMOST. The Large Sky Area Multi-Object Fiber Spectroscopic Telescope. Structure of LAMOST. MA mirror. Fiber Positioning. Fibers. MB mirror. Spectrographs CCDs. Optical System. Basic parameters of LAMOST. 4.5m/6.3m Schmidt telescope - PowerPoint PPT PresentationTRANSCRIPT
Status of LAMOSTThe Large Sky Area Multi-Object Fiber Spectroscopic Telescope
Structure of LAMOST
MB mirror
Fiber Positioning
Fibers
MA mirror
Spectrographs
CCDs
Optical System
Basic parameters of LAMOST 4.5m/6.3m Schmidt telescope The declination of observable sky area
ranges from -10 to +90. 20 square degree of the FOV 4000 fibers Spectrum resolution: VPH (Volume Phase Holographic) Grating R=1000, 2000, 5000, 10000
General Situation of the Project
The LAMOST project has its management under National Astronomical Observatories (hereafter NAOC) with its project office in the headquarter of NAOC, and its main workforce distributed in the Nanjing Institute of Astronomical Optics and Technology /NAOC in Nanjing, the Beijing part of NAOC and in the University of Science and Technology of China in Hefei. The project has its board and scientific and technical committee as usual.
Xinglong Station, NAOC
the site
Nanjing: NIAOT (NAOC)
Telescope
Instruments
Hefei: USTC
Science
Beijing: NAOC
Project HQ
Instruments & Software
Science
Schedules of LAMOST Project
Reviewed Approved Proposal Nov. 1996 Apr. 1997 Feasibility Study Jul. 1997 Aug. 1997 Preliminary Design Apr.-May 1999 Jun. 1999 Detailed Design Sep. 2001 Construction 2001-2008 First Light 2008.10
MA: 5.72mx4.4m reflecting corrector (24 sub-mirrors)MB: 6.67mx6.05m spherical mirror (37 sub-mirrors)
Technical Challenges of Active Optics
A combination of segmented mirror active optics and thin deformable mirror active optics on one mirror
Two large segmented mirrors needed to be actively controlled in the same time in the telescope.
With hexagonal deformable sub-mirrors. Wave front sensing on a variable
aperture
Active optics & supporting
MB
37sub-mirrors of MB ( July 13,2008)
24 sub-mirrors of MA 24 sub-mirrors of MA
24 sub-mirrors of MA ( Sept. 10, 2008)
Oct. 8, 2008
I mage Qual i ty vs I terat i on
0
1
2
3
4
5
6
7
8
9
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55I terat i ons
EE80
(arc
sec)
Mean=1.14″, Maintenance Mean=1.00″80%=1.21″, 80% Maintenance=1.14″
Statistics
0
1
2
3
4
5
6
7
8
9
0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1
EE80(arcsec)
Times
I mage Qual i ty vs I terati on
0
0. 5
1
1. 5
2
2. 5
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52I terati ons
( 3. 5 )每次迭代时间 分钟
EE80
(arc
sec)
At 5.2 degrees FOV
multi-optical fiber positioning
Fiber positioning unit
4000 fiber position units
16 Spectrographs
LAMOST-LRS Optical System
R1000/2000R5000/10000
R5000/10000
R1000/2000
Blue (370~590nm)
Red (570~900nm)
Grating
Blue branch
Red branch
R
1000 3700-
5900 Å
5700-
9000Å
binning 500
- 1000
narrow slit
2000
5000 5100-
5400Å
8300-
8900Å
- 5000
narrow slit
10000
Resolution powers
Spectrographs
VPHG (Volume Phase Holographic Grating)
E2V-CCD203
蓝区红区
南京
兴隆
Resolution of the spectrum
Operation software
OCS
SSS
TCS ICS DHS
InputCatalog
LAMOSTSpectr.Database
Software for automatic observation & data processing
catalogue processing
observation
OCS
SSS DPS
First light of the small system
On May 20 2007 The LAMOST small system (about 2m in diameter and have 250 firbers) got its first spectrum!
Sky
白天天光观测
5 月 25 日 15 时
6 月 5 日 18时
天光光谱
Select the targets
Field No. 9 June 22, 02h
203 targets
3600
123 Spectrum
Component & Total Efficiency
0.00
0.20
0.40
0.60
0.80
1.00
370 450 550 650 750 850
Wavelength(A)
Effi
cieny
telescope
fiber
Spectrograph
CCD
total
Efficincy
R 波段 Observe data ( Sky) : 12.0% Theoretical value : 16.5%
中值为 1
July 2008 MB: all 37 sub-mirrors MA: all 24 sub-mirrors Co-focus for MB: <0.4” To test active optics
Spectrographs: 16 Fiber positioning units: 4000
Wireless control system has tested
August 24 : 4000optical fibers
completed August 30 : 16 spectrographs
completed
LAMOST completed all hardware
Test spectra (Aug.5, No. 3 号 spectrograph
)
Blue Red
Relative efficiency ( No.6 spectrograph-blue )
Efficiency of spectrograph 370~900nm
Target : 35% ( peak ) According to test on reach parts: 50% According to test on whole spectrograph: 43%
Sept. 28 More than 2000 spectra got in one
test observation Oct. 13
About 3000 spectra got in one test observation
Spectra of stars ( 28/9/2008)
Red Blue
Plan
2009: Technical commission period 2010: Scientific commission period 2011: start regular spectroscopic survey
2009: Stability
Active optics Dome seeing
Efficiency Fibers Spectrographs CCDs
Scientific observations Open clusters, M31, selected area
survey, …
regular spectroscopic survey
2010-2015
Working groups for Extragalactic survey Galactic survey
input catalog for LAMOST (end of 2009)
SDSS 2DF LAMOST
Aperture 2.5m 4m 4m
Field of View 3 2 5
Number of Fiber
640 400 4000
Spectral resolution
1800-2100 1000 1000-2000, 5000-10000
Spectral ranges( Å )
3900-6100 6000-9100
3600-8000 3700-6200 5100-54006000-9000 8300-8900
Diameter of Fiber
3 ”(180mu) 2.16”(140mu)
3 ”(320mu)
Mini Distance of Fibers
55 ” 12 ” (30”) 40 ”
S/N 4.5/pix (g=20.2) 13/pix (mean) 11/pix (20.5, 1.5h)
Limited Magnitude
i=15-19.1,20.2(q)r<17.7(g)
bj 18.25-20.85(q)
bj 17-19.45(g)
B<20.5
Fiber Position Accuracy
0.5 ” Sqrt(1 ”+0.25”^2)~1.03” 0.5”(3 sigma)
LAMOST will become the most effective spectroscopic survey telescope, and the most powerful facilities for researches of wide field of view and large sample astronomy.
LAMOST is a National large astronomical instrument, it will open to all Chinese Astronomer.
We make the first call for observational proposal (2008-04)
How can we do better than 2dF and SDSS?
Large Aperture Large field of view More fibers
But XingLong station ??
Weather at Xinglong Site
Average temperature 7~8 , lowest -22.5 , highest ℃ ℃33.0℃94%(332 days) daily temperature difference less than 12℃
Average wind speed 2.4m/s~3.1m/s . About 90 days in a year instant wind speed >8m/s
Yearly average relative humidity 57%, about 5.7%(21 days), RH > 90%. Precipitate days ~20 days/yr
Observing nights ~200 nights/yr
Seeing by BATC
Seeing by BATCSeeing ~ 2” -3”
ExtinctionKv ~0.1 -0.33
Sky Brightness
Mv ~ 20.5 -21.5 /sq. degree
Key Projects
Extra-galactic spectroscopic survey —
Galaxy and QSO redshift survey Stellar spectroscopic survey — Structure of the Galaxy, and so
on. Cross identification of multi-
waveband survey.
Extra-galactic spectroscopic survey —
Galaxy and QSO redshift survey
Magnitude limited sample
• North Galactic Pole region:
~7700 degree2 r<18.8 ~2.6X106 gal.
• South Galactic Pole region:
~4000 degree2 r<19.5 ~2.6X106 gal.
Redshift survey of Galaxy
Low Resolution spectroscopy:
• To obtain the spectra of faint celestial objects (Galaxy and AGN) with R=1000 spectral resolution, S/N=10.
• Wavelength range: 370—900 nm
• From SDSS DR6 data select about 2.6X106 galaxies
Luminous Red Galaxy (LRG) galaxies survey:
i< 20.0 ~1.5X106 gal.
LRG sample
Advantage to select LRG• Red color → easy to find the candidate• Most luminous galaxy → Map large
cosmological volume• Correlated with cluster
→ To detect and study the clustering
QSO survey
• Combine the high quality digital image data of SDSS (5 colors) with powerful spectroscopic capabilities of LAMOST to conduct a deep wide field spectroscopic suevey for Quasars
Deep survey
• Select few 100 degree2 field
deep spectroscopy survey to
i~ 20.5
The mean redshift is about Z=0.3, Some of these sample could go to as deep as Z=0.5
Deep Field selected
RA (2000) DEC(2000)• COSMOS field : 10:00:00 02:12:00• AKARI NEP 18:00:00 +66:36:00 • Lockman-Hole field : 10:47:00 58:02:00• H1K field : 14:00:00 00:00:00• ELAIS-North1 field : 16:11:00 55:00:00
A detailed scientific case
– Studies of large-scale structure– Baryon Acoustics Oscillations => Dark energy– Formation and evolution of galaxies – AGN physics – The relation between galaxies and the IGM – Constrain dark energy from cluster counts and Alcock-
Paczsynki test – Accurately measure luminosity functions & star-
formation rate densities with redshift & environment– Detailed studies of local low-luminosity galaxies
The structure and Evolution of The Milk Way
• To get spectrum of 5×106 stars.
• Sloan Extension for Galactic Underpinnings and Evolution (SEGUE) obtain ~ 250,000 spectra of Galactic stars
• Stellar spectroscopy plays a crucial role in the study of our Galaxy, not only providing a key component of the 6-dimensional phase space of stellar positions and velocities, but also providing much-needed information on the chemical composition of individual stars. Taken together, information on space motion and composition can be used to unravel the formation process of the Galaxy.
Accuracies and our GalaxyLAMOST+
Welcome you to use LAMOST in the future