Talk Plan. Short-period Mira variables Ideal probe to investigate the Galactic structure. 岡山超広視野赤外線カメラによる K-band 銀河面モニタ

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1 岡山超広視野赤外線カメラによる K-band 銀河面モニタ 柳澤顕史 坂本強 吉田道利 泉浦秀行 沖田喜一 清水康広 ( 国立天文台 岡山 ) 中田好一 ( 東京大学 ) 山室智康 ( ジェネシア ) 河合誠之 ( 東京工業大学 ) Talk Plan 1. Introduction Short-period Miras as tracers of the Galactic Structure 2. OAOWFC Instrument overview Expected performance Current status 3. Summary Short-period Mira variables Ideal probe to investigate the Galactic structure Short Period (P < 300 d) 1. Old population 5 to 10 Gyr Distribution reflects mass distribution 2. Distance measurement Period Luminosity Relation at K-band 3. Bright & Brightest in the NIR L solar G.C., 20kpc for p=180 days K Period-Luminosity relation at K-bandK O rich Mira C rich Mira log P Dispersion = +/ mag. ( Feast et al. 1989)

2 Short-period Mira survey has never been made. Why? Astronomical point of view Interests has been focused on violent mass-loss phenomena. OH/IR stars, long period (P>300) Mira variables Technical point of view A lack of large-format NIR array 62 x 58 InSb (1986), 256 x 256 HgCdTe (1989), 1K x 1K HgCdTe (1994) This work Make a wide-field camera F.o.v. 1 sq.deg. HAWAII2-RG array Survey LPVs throughout the Galaxy Focused on short-period Miras Talk Plan 1. Introduction Short-period Miras as a tracer of the Galactic Structure 2. OAOWFC Instrument Expected performance Current status 3. Summary The OAO 0.9m Telescope Manufacturer : NIKON (present) Manufacturer : IHI Completion: 1959 Completion: 1959 Mount : Fork Equatorial Rotation Speed: 3.0 deg / sec Slew Speed: 1.5 deg / sec

3 Optical Layout NIR Detector : HAWAII-2 RG PACE Secondary Field Lens (CaF2) Collimator (s-fpl53 + s-til2) Cold Stop Field Flattener (s-fpl53) Tertiary Mirror Primary Mirror Quasi-Schmidt Forward Cassegrain Detector(HAWAII2) 2006/07/06 木曽シュミットシンポジウム2006 Filter HAWAII-2 RG PACE Manufacturer : Rockwell Science Center Photo Sensor : HgCdTe Cut-off Wavelength : 2.5 um Format : 2048 x 2048 Pixel size: 18 um x 18 um Sensitive Area: 36.8 mm x 36.8 mm Full Well : 1 x 10 6 e-/pixel Optical Fill Factor : > 0.98 Operating Temperature : > 30 K Max. QE : 65 2 um Readout Noise : 20e- # of output : /07/06 木曽シュミットシンポジウム Typical 2006 Readout Time : 0.8sec 0.95 deg OAOWFC : FOV 2006/07/06 木曽シュミットシンポジウム deg Galactic Center By SIRIUS Telescope Effective Diameter Optical configuration Overall F-ratio Central Obscuration Detector Format Pixel Size Sensitive Area Field of View Readout Time Readout Noise Operating Temperature Specifications OAO 36-inch Telescope 910 mm Forward Cassegrain + Cooled quasi-schmidt F/ % HAWAII 2-RG (HgCdTe/MBE) Rockwell μm 18.0 μm 1.6 arcsec 1.6 arcsec mm sq.deg. 1.0 sec 30 electrons 780K Filter Y, J, H, K s (MKO system) + ND(0.05) Cooling 2006/07/06 Refrigerator 木曽シュミットシンポジウム2006 Data processing Apply Image subtraction to extract variables

4 Overview of the OAOWFC Cross sectional view of the quasi-schimdt cryostat 1,776 W = 120 kg 416 1,310 80K K 3,519 1,776 Top Ring Secondary Mirror Cryostat Vessel Center Section Support Ring Primary Mirror Estimation of Detection Limits Estimation conditions S/N = 30 Central Obscuration : 0.35 Readout Noise: 40 e - Total Throughput: 0.22 Aperture Radius: 5 pix Dark Current: 0.1e - /sec Sky Brightness Mu J =14.5 mag/arcsec 2 Mu H =12.0 mag/arcsec 2 Mu K =12.0 mag/arcsec 2 Survey Efficiency Assumption 240 sec for a given field Overhead (pointing, filter exchange) included. Observe 8 hours/night 37% observable night Efficiency 14 sq.deg. / hour 108 sq.deg./ night 840 sq.deg. / 3weeks

5 Sky coverage: 840 sq.deg. Replacement of the Top-Ring 3 deg. Trial fitting of the support ring Trial Fitting of Mirror Cell to Support Ring

6 Cryostat 納品 Cryostat 納品 Cryostat 引渡し Cryostat 引渡し

7 94cm 主鏡金蒸着 94cm 主鏡金蒸着 94cm 主鏡金蒸着 HAWAII-2RG 納品

8 H2RG Astro-J/K QE T = 80K 500 mv Bias Sensitivity in K-band Sensitivity in J-band Number of pixels 2.50E E E E E+04 QE Astro-J Mean = 70.9 % Sdev = 2.9% Operability = 99.73% QE Astro-K Mean = 75.7 % Sdev = 3.4% Operability = 99.73% QE J-band QE K-band 0.00E QE CDS readout noise 77K Jul Oct Nov Winter Spring 2007 Milestone 光軸測定 クライオスタット望遠鏡へ装着 HAWAII-2 RG 駆動 エンジニアリング ファーストライト 試験観測 本観測開始

9 Summary Investigation of the Milky-Way Galaxy Search for short-period Miras OAOWFC Renew 0.9m telescope Modified UKIRT-WFCAM type optics HAWAII-2 RG (2K x 2K HgCdTe, Rockwell) FOV: 0.95 x 0.95 sq.deg. K=13.0(S/N=30) with 45 sec exposure. Survey efficiency: 840 sq.deg. / 3 week Survey will start in 2007