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

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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

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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

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0. 5

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1. 5

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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