2MASSᵪᶨ学ᶕ近赤外᷇᳐ᷫᶶᷙ᳐᷑処理ᶇᶽ᷿᷂᷑作成
2MASS Data Release Documentation
ᶱ読ᶲᶆᲾ我᳎ᶊ足ᶩᶉᵣ所ᶱ学ᶕ

2004年Ჽ中島 康Ჽ

2MASS Data Release Documentation
2MASSᶍ᷊ᷬ᳐ http://www.ipac.caltech.edu/2mass/
2MASS Documentation
http://www.ipac.caltech.edu/2mass/releases/docs.html

The 2MASS All-Sky Data Release (2003 March)
http://www.ipac.caltech.edu/2mass/releases/allsky/doc/explsup.html

ᵫ最新ᶍᶡᶍᶉᶍᶆᲾᵼᶫᶱ読ᶟᲿThe 2MASS All-Sky Data Release
I. Introduction
II. User's Guide to the 2MASS All Sky Data ReleaseIII. 2MASS Facilities and Operations
IV. 2MASS Data Processing
V. Catalog Generation
VI. Analysis of Release Catalogs

IV.とV.を重点的に読み解く。
ただしI. II. VI.も触れる。

I. Introduction• 2MASS Overview• 近赤外᷇᳐ᷫᶶᶍ歴史ᶍ記述Ჿ(The Two Micron Sky Surveyᶉᶈ)• 1.3m + 3x256x256 array, J(1.24), H(1.66), Ks(2.16)

North : 1997/6 - 2000/12 : Level1 Science Requirement 691 nights
South : 1998/3 - 2001/2 : 750 nights
rawdata : 24.5TB
covering 99.998%• All-Sky Data Release

Point Source : 470,992,970
Extended Source : 1,647,599
Image Atlas : 4,121,439• The 2MASS Sky• J=16.0, H=15.0, Ks=14.5 (10-sigma)

限界等級ᶍ非一様性ᶍ記述Ჿ
銀極ᶆᶍ系外銀河ᶍᶽ᷻᳐(星形成屋ᵴᶲ)•Executive Summary of 2MASS All-Sky Release
Data Productsa. Point Source Catalog (PSC)
470,992,970
Positions, magnitudes, astrometric and photometric uncertainties,
flags indicating the quality of the source characterizations,associations with Tycho 2 or USNOA-2.0 optical catalog sources,
known solar system objects are presented for each source.
b. Extended Source Catalog (XSC)
1,647,599 (97%ᵫgalaxy)
Positions, magnitudes measured in a wide variety of ways, photometric
uncertainties,
associations with several external catalogs,
a number of flags and scores indicating the quality of the measurements,
the likelihood of "extendedness" are presented for each source.

c. Image Products
i. Atlas Images
1,373,813 x 3 (=4,121,439)枚ᶍAtlas ImageᶇᵣᵥFITS画像
8.5' x 6᳴ᶍSurvey Tileᶇᵣᵥ᷸ᷝᷕᷚᵫ59,731ᵡᶪᲿ
Tileᶎ23枚ᶍAtlas Imageᶊ分割ᵴᶫᶪᲿᵼᶍᵥᶀ22枚ᶎ512x1024(1"/pix)Ჾ1枚ᶎ512x698(1"/pix)( camera-pixelᶎ2"/pix, atlasᶎ1"/pix )位置ᶇ測光ᶿ᷹᷵ᷨ᷾᳐᷉᷼ḅᶍᷙ᳐᷑ᵫᷪᷕ᷒ᶊ記載
Quicklook Imageᶇᵣᵥᶍᶡwebᶆ配給ᵴᶫᶅᵣᶪᲿ
http://irsa.ipac.caltech.edu/applications/2MASS/QL/
1/20ᶊ圧縮ᵶᵾᷙ᳐᷑Ჿ測光ᶊᶎ向ᵪᶉᵣᲿ
ii. Extended Source Postage Stamp Images
XSCᶍ᷏᳐᷋ᶍ周辺ᶍ切ᶩ出ᵶᲿ
21"x21"ᵪᶨ301"x301"ᶝᶆ᷇ᶶ᷌ᵫ選ᶘᶪᲿ• Cautionary Notes• Sky Coverage

Image Atlas : 99.998%
PSC : 99.65% (J), 99.51%(H), 99.56%(Ks)
XSC : ˜98%
足ᶩᶉᵣ分ᶎ主ᶊ明ᶪᵣ星ᶱᷰ᷋᷁ᵶᵾ効果Ჿ• Physical Gap : 望遠鏡ᶍpointing error (0.71 deg^2)Ჾ
• Effective Gap in the catalog : tile ᶍ端ᵪᶨ 10" (PSC), 15"(XSC)
以上離ᶫᵾ᷏᳐᷋ᶍᶞ拾ᶂᶅᵣᶪᲿ
tileᶍᷬᶴᶍ重ᶉᶩᵫ20"以下ᵿᶇᶽ᷿᷂᷑ᶊᶎᶍᶨᶉᵣᶡᶍᵫ生ᵷᶪᲿ
(1.26deg^2 for PSC, 1.65 for XSC)

• 明ᶪᵣ星 : 106 deg^2 in J, 156 deg^2 in H, 178 deg^2 in K
• Effective loss of faint source coverage due to confusion in the
Galactic planeII. User᳓s Guide to the 2MASS All-Sky
Data Release
2. Point Source Catalog
a. Point Source Catalog Column Descriptions
b. How to Use the 2MASS PSC - A PSC Practical User᳓s Guidec. PSC Source Selection Criteria
d. General Properties of the PSC
e. Photometric Properties
f. Astrometric Properties
g. Solar System Objects

例III. 2MASS Facilities and Operations•

留意点• 積分ᷕᷚ᷍

Ჽ[Read1 (R1) 51-ms, Read2(R2) 1.3s, doubly-correlated difference
frame Read2 - Read1 (R2-R1)]
R1ᶡ残ᵶᶅᵣᶅ明ᶪᵣ᷏᳐᷋ᶍ測光ᶊ使ᶮᶫᶪᲿ• image qualityᲽᲽthe best image
for Mt.Hopkins : 2.7"-2.8" FWHM
for the CTIO : 2.5"-2.7" FWHM

• zero-point Offsets

夜毎ᶊ測光ᶍ᷎᷿点補正ᶱ決ᶠᶪᲿ
時間ᶍ関数ᶇᵶᶅᶡ考慮zero-pointᶍ変化(右図)
急激ᶊ変化ᵶᶅᵣᶪᶇᵲᶬᶎᶽᷳ᷻ᶍ窓ᵩᶧ
ᶒ主鏡ᶍ᷁᳐ᷝ᷼ḅ᷂ᵫᵡᶂᵾ

• Scanning Strategy

赤緯方向ᶊ57᳕/秒ᶆ᷋ᶿ᷵ḅᲿ視野ᶍ1/6ᵫ重ᶉᶪᲿ
1.3secx6=7.8secᵫ1点ᶆᶍ総積分時間
sub-pixel ditheringᶆ空間分解能ᶱᵡᵱᶪ• Photometric Calibration Strategy
1時間ᵩᵬᶊ標準星(Persson or UKIRT)ᶱ含ᶟtileᶱ観測ᵸᶪ
数個ᶍ同ᵷ標準星tile(1᳴)ᶱ何回ᵪ観測(airmass補正)
2次標準星ᶽ᷿᷂᷑ᶍ作成 (Nikolaev et al. 2000)

IV. 2MASS Data Processing• Processing Pipeline Overview
2MASS Production Processing System (2MAPPS) ᶱ用ᵣᶅimageᶍ作成Ჾpoint and extended source dataᶍ作成ᵫ行ᶮᶫᶪᲿ

• basic scan processing• R1(51 ms) ᵩᶧᶒR2-R1(1.3 s)ᷧ᷾᳐ᷲᶍdark引ᵬᲾflat割ᶩᲾsky補正• point source検出Ჾ位置決ᶠᲾ明ᶪᵣ᷏᳐᷋ᶍ測光• image combine -> Atlas image• Atlas imageᵪᶨpoint sourceᶍ検出• point sourceᶍ位置ᶇ明ᶪᵴᶍ測定Ჿ明ᶪᵣ星ᶆ作ᶨᶫᵾ人工的ᶉᶡᶍᶍ同定• 3ᷢḅᷛᶍ᷏᳐᷋ᶍ同定Ჾ位置ᶎTycho2 (2.5million) ᶊᶧᶂᶅ決定Ჿ• 点源ᶇᵶᶅ分解ᵴᶫᶅᵣᶪᵪᷓᶹᷕ᷁Ჿ広ᵫᶂᵾ᷏᳐᷋候補ᶍ明ᶪᵴᶇ形Ჿ• post scan processing• 測光calibration決定上記• calibrationᶱpoint sourceᶇextended sourceᶇAtlas imageᶊ適用• ᷙ᳐᷑ᶍ質ᶱ確認• source list, image, scan informationᶱdatabaseᶊ入力Ჿ• pipelineᶍ産物ᶎᲾbandᶱ合ᶮᵺᲾ測光補正Ჾ位置決定ᵴᶫᵾpoint sourceᶇextended sourceᶍlistᲿᵲᶫᶨᶍlistᶍ積ᶞ重ᶌᵫdata base ᶇᶉᶩ
catalogᶇᶉᶪᲿ質ᶍ向上ᶍᵾᶠᶊ行ᶂᵾᵲᶇ
2nd Incremental ᵪᶨᶍ改善点ᶍ記述• Instrumental Calibration• Atlas Images• Point Source Characterization• Extended Source Characterization• Astrometry• Artifact Identification• Photometric Calibration• Minor Planet Identification• Quality Assurance• Instrumental Calibration• ᵼᶫᵽᶫᶍarrayᶆ2次元saturation map使用Ჿ以前ᶎ全ᶅᶍpixelᶊ
一様ᶊconstant saturation thresholdᶱ与ᵧᶅᵣᵾᲿ(saturationᶊ場所依存᳅)• 全ᶅᶍᷙ᳐᷑ᶱ使ᶂᶅᲾ最良ᶍCannonical DarkᶇFlat-field(ᵼᶫᵽᶫᶍ日ᶊ最適化)ᶱ作成ᵶᵾᲿ(Flat-field images incorporate corrections for crossscan biases observed in point source photometry. -> 何᳅)•Atlas Images• 流星ᶍ跡ᶍ検出ᶇblanking• backgroundᶍ傾ᵬᶱ改良Ჿ• backgroundᶍᷠᶶ᷌ᵫᶧᶩ本当ᶍPoisson noiseᶊᶉᶂᶅᲾdetection
thresholdsᵫᵬᶀᶲᶇ設定ᶆᵬᶪᶧᵥᶊᶉᶂᵾᲿ(Result is that Atlas
Image backgrounds may not match smoothly in-scan. ->何᳅)• Single pixel coverage allowed into Atlas Images to minimize᳔holes᳕. -> 何᳅• Point Source Characterization• noiseᶍ評価ᶱ改良Ჿ(source detection thresholdsᶊ関連)低周波ᶍ
background 構造ᶊ敏感ᶆᶎᶉᵮᶉᶂᵾᲿ

• R1ᶆᵴᶀᶂᵾ星ᶍ検出Ჿ1次元ᶍradial profile fittingᶱ使ᶂᶅ重心ᶇ明
ᶪᵴᶍ評価Ჿ

• PSFᶍᷕᷚ᷍ᶍ改良Ჿvariance map(array上ᶆᶍ᳅)ᶍ改良Ჿ全ᶅᶍ

arrayᶇ全ᶅᶍ時期ᶊᶃᵣᶅᲿ結果ᶇᵶᶅᲾ質ᶍ向上ᵫuncertainty
estimation vs. brightness and chi-squared statistical distributionᶊ
見ᶨᶫᵾᲿ• R2-R1ᶆᶍ測光ᶆᲾSeeingᶊ依存ᵶᵾᲾaperture photometryᶆᶍ

curve-of-growthᶇnormalizationᶍlook-up tableᶱ使用Ჿᶺ᷻᳐ᵫ
小ᵴᵮᶉᶂᵾᲿscan毎ᶊ求ᶠᶅᵾᶡᶍᶇ比ᶘᶅᲿ• Astrometry• ᶧᶩ高密度ᶍTycho2ᶽ᷿᷂᷑ᶱ使用• 焦点面ᶆᶍdistortionᶍ測定• 位置ᶇᵼᶍ誤差ᶍ補正ᶍ᷽ᷘ᳐ᷨᶱ作成ᲿᵲᶫᶊᶧᶂᶅᲾ星ᶍ数ᵫ少ᶉᵣ所ᶆᶍᷣᷧᶻ᳐ᷰḅ᷋ᵫᵡᵫᶂᵾᲿ

• Photometric Calibration• 全᷇᳐ᷫᶶᵪᶨ2次標準星ᶱ改良Ჿinternal consistencyᶊ最大ᶍ努力ᵫᶉᵴᶫᵾᲿ変光星ᶡ削除ᵴᶫᵾᲿ• 時間変化ᵸᶪ大気吸収ᶍ᷽ᷴᷙᶱ用ᵣᵾ(varies by month)Ჿ全ᶅᶍ
᷇᳐ᷫᶶᷙ᳐᷑ᶱ用ᵣᶅglobal solutionᶱ出ᵶᶅᵼᵲᵪᶨ導ᵬᵿᵶᵾᲿ

• ᶧᶩ高次ᶍᷧᶵᷕᷚᶱ夜毎ᶍzero-point offsetᶊ適用ᲿPiece-wise fit

ᶱJᷢḅᷛᶊᲾlinear fitᶱHᶇKsᷢḅᷛᶊ使ᶂᵾᲿᵲᶫᶨᶍfittingᶆ標準星
ᶍoverall residualᶱ最ᶡ低ᵮᵶᵾᲿ•Instrumental Frame Calibration• Frame Readouts
2回ᶍ読ᶞ出ᵶᶍR2-R1ᶱ主ᶊpipeline処理ᲿR2ᶆ᷇ᷓᶪ星ᶎR1ᶆ測定Ჿ

• Darks/Electronics Bias Characterization• 夜毎ᶍdarkᶎ何週間-何Ḉ月ᶊᶮᵾᶂᶅ安定• 夜毎ᶍdarkᶎ振ᶪ舞ᵣᵫ同ᵷ期間ᶍᶡᶍᶊᶃᵣᶅ平均ᵴᶫᵾ᳕grandcanonicals᳕ᵫ作成ᵴᶫᶪᲿᵼᵶᶅᵼᶍ期間ᵸᶘᶅᶍᷙ᳐᷑ᶊ適用ᵴᶫᶪᲿ• 振ᶪ舞ᵣᵫ変ᶮᶪᶍᶎᲾ機械ᶱᵣᵷᶂᵾᶇᵬᲿ
• Northᶆᶎ16-periodᲾSouthᶆᶎ4-periodᶍcanonical darkᶱ使用Ჿcanonical darkᶍlist• Flatfield/Responsivity Characterization• flatᶎtwilight skyᶱ撮ᶂᶅ作ᶪᲿmedianᵫ1ᶊᶉᶪᶧᵥᶊ規格化• 毎日ᶍflatᶎ5日分ᵴᵪᶍᶛᶂᵾ平均(canonical flat)ᶇ比ᶘᶪᲿᵼᵶᶅᵼᶍ

canonical flatᶇᶧᵣ一致ᶱᵶᶅᵣᵾᶨᲾᵼᶍ日ᶍflatᶱ加ᵧᶅ新ᵾᶉcanonicalflatᶱ作ᶪᲿ一致ᵶᶉᵪᶂᵾᶨ(雲ᶍ影響ᶇᵪ)Ჾᵼᶍ日ᶍᶎ加ᵧᶉᵣᲿᶇᵣᵥᵲᶇᶱ2nd IncrementalᶍᶇᵬᶊᶣᶂᶅᵣᵾᲿ• 上記ᶍᶧᵥᶊ作成ᵶᵾ全時期ᶍflatᶍlibraryᶍ解析ᶍ結果Ჾ何Ḉ月ᶇᵣᵥ᷑ᶶ᷽ᷲ᷋᷃᳐ᶆ安定ᶉᶍᶆᶡᶂᶇ長期間ᶆᶍ平均ᶍflatᶱ作成Ჿ

many of the flatfield drifts seen across timescales of weeks to months are seasonal in natureand more likely reflect changing illumination patterns within the observatories rather than actual
drift in electronics responsivities. Therefore more uniform canonical flats averaged over longer
periods have been adopted give more consistent cross-scan biases (illumination-derived
variations in flats across the detector that do not correlate to actual responsivities cancontribute to photometric biases as a function of horizontal position within the image).

• ᵲᵥᵶᶅ᳕grand canonical᳕ flatᶱ素性ᶍᶧᵣflatᶍmedianᵪᶨ作成Ჿ
• Northᶆᶎ8-periodᲾSouthᶆᶎ4-periodᶍᲽ᳕grand canonical᳕ flat

NORTHERN HEMISPHERE FLATS
Dates
Bands
---------------------------a 970000 970802 J1 H1 K1
b 970903 970922 J2 " "c 970927 971026 J3 " K2
d 971027 980918 J4 H2 K3
e 980919 981020 " H3 K4
f 981021 990720 J5 H4 K5
g 990721 000901 J6 H5 K6h 000902 050000 " H6 "SOUTHERN HEMISPHERE FLATS
Dates
Bands
---------------------------a 970000 990117 J1 H1 K1
b 990118 990226 J2 H2 K2
c 990227 990624 J3 H3 K3
d 990625 050000 J4 H4 K4• Frame Calibration Procedure
1. R1-R2ᷧ᷾᳐ᷲᶱ作成
2. ᷒᳐᷁引ᵬ
3. ᷧ᷻ᷕᷚ割ᶩ次᷊ᷬ᳐ᶊ行程図

4. sky引ᵬ• 上記行程3ᶝᶆ終ᶮᶂᵾᷧ᷾᳐ᷲᶱ少ᶉᵮᶇᶡ42枚使用ᵶᶅᲾskyᶱ作成ᵸᶪᲿ(sigma-trimmed average)• 最終的ᶉcalibrated frameᶍ᷂ᷢᷕ᷁᷻ᶸḅ᷽ᷛ᷾ᷫᶎ元᳎ᶍ᷋ᶽᶶ᷾ᷫ
᷽ᶇ同ᵷᲿ• ᵲᶫᶆcombineᵸᶪᶉᶩsource detectionᵸᶪᶉᶩᶍ準備ᶎOKᲿ•Atlas Image Generation
8.53'x17.07' (512x1024, 1᳕/pix)ᶍAtlas imageᵫ6枚ᶍcalibrated framesᵪᶨ作成
declinationᶆ隣ᶇᶎ54"重ᶉᶪᲿFITSᷪᷕ᷒ᶊᶎastrometric solutionᶇphotometric zero point ᵫ含ᶝᶫᶪᲿ重ᶌ合ᶮᵺᶎ相対的ᶉ位置関係ᶱ見積ᶡᶂᵾ後ᶊᲾfluxᵫ保存ᵴᶫᶪinterpolation kernel (後述)ᶱ用ᵣᶅ位置合ᶮᵺᵴᶫᶪᲿ
極端ᶊᷠᶶ᷌ᶍ大ᵬᵣpixelᲾ流星ᶣ衛星ᶍ軌跡Ჾ宇宙線ᶎ
ᷰ᷋᷁ᵴᶫᶅᵪᶨinterpolationᵴᶫᶪᲿ重ᶉᶪframeᶍbackgroundᶊᵡᵥᶧᵥᶊsky levelᵫ調整ᵴᶫᶪᲿ継ᵭ目ᶍᶉᵣ画像ᲿᵾᵿᵶᲾskyᵫ急激ᶊ変動ᵸᶪᶇ(雲ᶣOHᲾ明ᶪᵣ星)ᵥᶝᵮᵣᵪᶉᵣᲿmaskᶍᵾᶠᶊᲾ1枚ᶡᵼᶍpixelᶊ値ᶱ与ᵧᶉᵣ場合Ჾ0ᵫ入ᶪᲿimageᶍ端ᶆᲾ2枚以下ᶍᷧ᷾᳐ᷲᵶᵪ値ᵫᶉᵣ場合Ჾᵼᶍpixel
ᶊᶎ0ᵫ入ᶪᲿ

• a bias reset decay artifact (我᳎ᵫᵣᵥᶇᵲᶬᶍreset anomaly)
᳔a background bias which decayed across the lines in each detector quadrant
and varied from frame to frame᳕
Northᶍ方ᶍᶽᷳ᷻ᶍJᶇHᶆ確認ᵴᶫᶅᵣᶪᵲᶍbiasᶎ各frameᶍ各lineᶆᶍ᳔the lower quartiles (四分位; ᷙ᳐᷑ᶱ小ᵴᵣ方ᵪᶨsortᵶᶅ25%ᶍᶇᵲᶬ)᳕ᶱ使ᵣᲾ空間的ᶊ比ᶘᶅ除去
quadrantᶱᶝᵾᵣᶆᶍoffsetᶇslopeᶎframe間ᶆᶍ残差ᵫ最小ᶊᶉᶪᶧᵥᶊ計算詳細ᵫ᷼ḅ᷁ᵴᶫᶅᵣᶪᶍᶆ見ᶅᶞᶪ• bias slope problem
http://spider.ipac.caltech.edu/staff/gene/analysis/hslope.html
᳔a decaying offset as a function of line, discontinuous at quadrant boundaries᳕ᵲᶫᶎcoadded imagesᶆbackground noise levelᶼ᳐᷒᳐ᶍ大ᵬᵴᶍ不連続ᶇᵶᶅ
現ᶫᲾgalaxyᶣ点源ᶍ検出感度ᶇ信頼性ᶱ劣化ᵴᵺᶪ
decayᶎlinearᶆᶎᶉᵮᵩᵩᶧᵼexponential
上ᶇ下ᶍquadrantᶆdecayᶎ同ᵷᶆᶎᶉᵣ
西側ᶍ端ᶆᵲᶍ効果ᵫ強ᵣᵲᶇᵫ頻繁
exponential model ᶱ使ᶂᵾfittingᶱ用ᵣᶅ補正ᵶᶅᵣᶪᵫᲾ多少残差ᶎᶝᵿ残ᶪ明ᶪᵣ星ᶣOH/雲ᶍ影響ᶱ受ᵰᶅᵣᶪᶇᵬ• Image Estimation Using Kernel Smoothing
sub-pixelᶆᶍ位置合ᶮᵺᶇ測光ᶍᵾᶠᶊᲾinterpolationᵫ必要
pixel間ᶍfluxᶍ推測ᶍᵾᶠᶊGaussian Kernelᶱ用ᵣᵾSmoothingᶱ使ᵥ
smoothing lengthᶎ h=0.35 pixel ᶇ経験上決ᶠᵾ• Point Source Detection and Photometry• overview
J=9, H=8.5, Ks=8ᶧᶩᶡ暗ᵣ点源ᶎ1.3s積分ᶆ᷇ᷓᶨᵹᶊ6枚合成ᵶᵾᷧ᷾᳐ᷲᶆ
検出ᵴᶫᶪᲿᵲᶫᶨᶍ点源ᶊᶃᵣᶅ重心計算Ჾ測光(PSF fittingᶇmulti-aperture)ᵫᶉᵴᶫᶪᲿcurve-of-growth補正ᶡ行ᶮᶫᶪᲿdefault-magnitudeᶎPSF測光ᶍ結果
4.5 < J < 9, 4 < H < 8.5, 3.5 < Ks < 8 ᶍ点源ᶎ1.3s積分ᶆᶎ᷇ᷓᶪᵫᲾ51-msᶆ
ᶎ᷇ᷓᶨᶉᵣᲿ51-ms積分ᶍᷧ᷾᳐ᷲᶆ検出Ჾ重心計算Ჾaperture 測光Ჿ
J<4.5, H<4, Ks<3.5ᶍ点源ᶎ51-msᶆᶡ᷇ᷓᶪᲿᵲᶫᶨᶍ点源ᶎ51-msᷧ᷾᳐ᷲᶆ
検出ᶇ重心計算ᵶᲾ᷇ᷓᶂᶅᵣᶉᵣwingᶍ部分ᶱ使ᶂᶅᲾ1次元radial profile
fittingᶆ測光

S/Nᶍ十分大ᵬᵣ᷇ᷓᶂᶅᵣᶉᵣ星ᶍaperture測光ᵫ一番正ᵶᵣᶇ仮定Ჿ
curve-of-growth補正ᵶᵾaperture測光ᶊ対ᵶᶅᲾPSF測光ᶍ値ᵫnormalizeᵴᶫᶪ• Frame Source Detection and Aperture Photometrydark-flat-sky処理済ᶞᶍR1ᵩᶧᶒR2-R1ᷧ᷾᳐ᷲᶆ最初ᶍdetectionᶇaperture phot
目的:Atlas imageᶱ作ᶪᵾᶠᶍ位置決定(ᵲᵲᶆᶍpositionᶇ測光値ᶎᶽ᷿᷂᷑ᶊᶎ使ᶮᶫᶉᵣᲿAtlas imageᶆ再測定ᵸᶪᶍᶆ)ᲾR2-R1ᶆ᷇ᷓᶂᶅᵶᶝᵥ星ᶍ測光ᶱR1ᶆ(ᵲᶫᶎᶽ᷿᷂᷑ᶊ使ᶮᶫᶪ)point sourceᶎ局所的ᶉ強度ᶍᷦ᳐᷁(local maxima)ᶱ見ᶃᵰᶪᵲᶇᶆ検出Ჿ
位置ᶎ a maximum-likelyhood estimatorᶱ用ᵣᶅ決ᶠᶨᶫᶪ
等級ᶎ4" radius (2-camera pixel)ᶍaperture photometryᶆ決ᶠᶨᶫᶪ
全ᶅᶍpixelᶍ値ᵫ᷂ᷤ᷋ᷚ᷻ᷲ化ᵴᶫᶪᲿᵼᵲᵪᶨmedianᶇnoiseᵫ求ᶝᶪᲿ
ᵲᶍnoiseᶎ0.1587ᶇ0.8413 percentile pointsᶍ1/2ᶍ所ᶆ決ᶠᶨᶫᶪᲿlocal backgroundᵪᶨ4-sigmaᶱ越ᵸlocal maximaᶊᶃᵣᶅ以下ᶍ計算ᵫᶉᵴᶫᶪᲿ
ᵼᶍlocal maximaᶱ中心ᶇᵶᵾ3x3pixel領域ᶆᶍcentroidᵫ計算ᵴᶫᶪᵼᶍlocal centroidᶎinitial source positionᶇᵶᶅ使ᶮᶫᶪᲿᵼᵶᶅmaximum likelihood position estimation techmichᶱ用ᵣᶅᶧᶩ厳密ᶊ決定/* 計算ᶍ詳細ᶎᷣ᷋ */• (続ᵬ)aperture photometryᶎ上記ᶆ求ᶠᶨᶫᵾ場所ᶊᶃᵣᶅ行ᶮᶫᶪᲿ
skyᶍ値ᶎ半径=24"-30"ᶍ間ᶆ測定ᵴᶫᶪᲿᵲᵲᶆᲾ᷇ᷓᶂᵾᲾᷰ᷋᷁ᵴᶫᵾᲾ異常ᶊ
小ᵴᶉ値ᶍpixelᶎ除外ᵴᶫᶪᲿsigma-trimmed medianᵫskyᶍ値ᶇᵴᶫᶪᲿ
i. Bright Source (R1) Aperture Photometry
51msᶍR1ᶱ使ᵥᵲᶇᶆ᷒ᶶᷜᷱᷕ᷁᷾ḅ᷊ᵫ広ᵫᶪᲿ
1.3secᶍ場合Ჾ(J,H,Ks)=(9.5,9.0,8.5)ᵮᶨᵣᶆ᷇ᷓᶩ始ᶠᶪᲿR1ᶆᶍaperture
photometryᶍ値ᵫ用ᵣᶨᶫᶪᲿᲽᲽ
ii. Faint Source Detection
暗ᵣ点源(要ᶎᶚᶇᶲᶈᶍ点源)ᶎAtlas imageᶆ検出ᵴᶫᶪᲿAtlas imageᶎ zero-sum 4" FWHM Gaussianᶆ13-pixel sub-arrayᶊᶮᵾᶂᶅconvolveᵼᶍfiltered imageᶊthresholdᶱ設定ᵶᶅsourceᶱ同定Ჿcorrected centroidᵪᶨ位置ᶡroughᶊ計算Ჿ
ᵲᶍ検出方法ᶎ基本的ᶊᶎDAOPHOTIIᶍFIND᷿ᷩ᷋᷍ᶇ同ᵷᲿ(Stetson 1991)
ᵲᶍdetection listᶱ使ᶂᶅᲾscan 中ᶍseeingᶍestimateᲾphotometryᶱ行ᵥᲿ
detection thresholdᶎ3 x (noise level)Ჿnoise levelᶎimageᶍ᷂ᷤ᷋ᷚ᷻ᷲᶍ50%ᶇ
32.22%ᶍquantiles(変位値)ᶍ差ᶆ推算ᵸᶪᲿᵲᶍnoise-estimatorᶎconfusion noiseᶊ敏感ᶆ銀河面ᶉᶈᶆthresholdᵫ増加ᵸᶪ
iii. Very Bright Source Detection and Photometry
Read̲1ᶆᶡ᷇ᷓᶪ点源ᶎwingᶍ部分ᶆ測光ᵸᶪᲿ
2MASS Catalogᶆ最ᶡ明ᶪᵣ星ᶎOriḡ (J=-2.99,H=-4.01,Ks=-4.38)
analytic modelᶱ用ᵣᶪ
Seeingᶊᶧᶪ補正ᵫ重要(several x 0.1 magᵮᶨᵣ効ᵮ)0.1-0.2等ᵮᶨᵣᶍ精度ᶱ達成ᵶᶅᵣᶪᶨᵶ
詳細ᶎ別ᶍᶇᵲᶬᶆ
http://spider.ipac.caltech.edu/staff/cxu/2mass/bstar/grand̲psf/grand̲psf.html

• Profile-Fit Photometry
Atlas imageᵪᶨᶍphotometryᶇ位置推算ᶎprofile-fittingᶆ行ᶮᶫᶪ
detectionᶎAtlas imageᶆ行ᶮᶫᶪᵫᲾpoint source fitᶎ"performed directly on theflat-fielded pixel values in a stack of 6 frames"Ჽ(recombineᵴᶫᵾimageᶆ行ᶮᶫᶪᶍᶆᶎᶉᵣᶍᵪ᳅)
PSFᶍ形ᶇframe間ᶍ相対位置offset(Atlas imageᶱ作ᶪᶇᵬᶊ既知)ᶍ情報ᶱ元ᶊ行ᵥᲿ
数学的ᶉ詳細 : ᷣ᷋• Point Spread Function and Seeing Estimation
PSF libraryᶇᵣᵥᶍᵫbandᵳᶇseeingᵳᶇᶊ用意ᵴᶫᶅᵣᶪᲿ
2MASS pipelineᶍ中ᶆPSFᶱ作ᶪᶮᵰᶆᶎᶉᵣᲿ
ᶇᵣᵥᶍᶡ星ᵫᵸᵳᵮ少ᶉᵣᶇᵲᶬᶣ多ᵣᶇᵲᶬᶆ自動的ᶊPSFᶱ作ᶪᶍᶎ難ᵶᵣ
ᵼᶫᶊPSF作成ᶎCPU᷑ᶶᷲᶡ食ᵥᶍᶆPSF libraryᶱ使ᵥᶚᵥᵫᵪᶉᶩ速ᵣ
特定ᶍseeing sizeᶍPSF libraryᶎemipiricalᶊ作ᶨᶫᶪ(平均ᶍseeing sizeᵫᵼᶍsizeᶍ
single calibration scansᵪᶨ)明ᶪᵣ方ᵪᶨ50個ᶍ星ᶱ選ᶒᲾcentroidᶱᶇᶂᶅ位置ᶱ合ᶮᵺᶅPSFᶱ作ᶪᷧ᷾᳐ᷲᵩᶧᶒ星ᶍ選出ᶍ基準ᶎ以下ᶍᶇᵩᶩᲿ*scan中ᶍseeing parameterᶍ変化ᵫ小ᵴᵣᶡᶍ*星ᶍx-ᶇy-ᶍcentral momentsᵫ同ᵷ(10%以内)*同様ᶍ条件化ᶍ他ᶍPSFᶇconsistentᶆᵡᶪᵲᶇ
profile fitting photometryᶍᶇᵬᶍ適切ᶉPSFᶍ選ᶒ方Ჿ
seeingᶎ時間差18secᶊ相当ᵸᶪ17arcminᶍ中ᶆ決ᶠᶪᲿ
実際ᶍ間隔ᶎ星ᶍ密度ᶊᶧᶪᲿ星ᵫ少ᶉᵰᶫᶏ上記ᶍ3倍ᵮᶨᵣᶝᶆ長ᵮᶉᶩ得ᶪᲿ
ᶡᵶseeingᵫ上記間隔ᶧᶩᶡ早ᵮ変化ᵸᶪ場合Ჾseveral %程度ᶍ測光ᶺ᷻᳐ᵫᵡᶩ得ᶪᲿ本当ᶍimageᶍPSFᶇprofile fittingᶊ使ᶮᶫᶪPSFᵫ違ᶂᶅᵶᶝᵥᵪᶨᲿ• Aperture Photometry, Curve of Growth Correction and Photometric Normalization
i. Aperture Photometry
Atlas imageᶆ検出ᵴᶫᵾnon-saturated sourceᶊᶃᵣᶅaperture測光ᶱᵸᶪ
1. Profile-fit photometryᶊ絶対測光ᶍ᷽᷋᷃᳐ᶱ与ᵧᶪ
2. objectᶍdetectabilityᶍ統計ᶍᵾᶠᲾ
3. profile fittingᵫ収束ᵶᶉᵣᶇᵬᶍback-upᶍᵾᶠProfile-fittingᶇ同様ᶊᲾ測光ᶎindividual framesᶆ行ᶮᶫᶪ
apreture radiusᶎ3"ᵪᶨ14"ᶝᶆ1"᷋ᷘᷕᷩᶆ複数radiusᶆ行ᵥᲿ
skyᶎ14"-20"ᶍ円環ᶆ計算ᵴᶫᶪᲿskyᶎᶝᵹ᷇ᷓᶂᵾᲾᷰ᷋᷁ᵴᶫᵾᲾ異様ᶊ小ᵴᵣ値Ჾ
ᶍpixelᶱ除去ᵶᶅ計算Ჿsigma-trimmed medianᶱ使ᶂᶅ計算ᵴᶫᶪᲿ
6回ᶍ測定ᶎ重ᶞᶉᵶᶆ平均Ჿ᷏᳐᷋ᶍ場所ᵪᶨ4"以内ᶊᷰ᷋᷁ᵴᶫᵾ᷽ᷦ᷁᷍ᵫᵡᶪᷧ
᷾᳐ᷲᶎ平均ᵪᶨ除外ᵴᶫᶪᲿndet᷂ᷧ᷻ᷕᶎ3sigma以上ᶍdetectionᵫᵡᶂᵾᶡᶍᶍ数ᶇ測定可能(᷽ᷰ᷋᷁ᷦ᷁᷍等ᵫᶉᵪᶂᵾ)ᶉᷧ᷾᳐ᷲᶍ数ᵫ記ᵴᶫᶅᵣᶪᲿ
"665634"ᵿᶇJᷢḅᷛᶎ6枚全部ᶆ可能ᶆ6個ᶍdetectionᲾHᷢḅᷛᶎ6枚ᶆ可能ᶆ5枚ᶆ
detectionᲾKᷢḅᷛᶎ4枚ᶆ可能ᶆ3個ᶍdetectionᵫᵡᶂᵾᲿ

ii. Curve-of Growth Correction
2MASSᶍaperture測光ᶆᶎᶇᶩᵡᵧᵹ4᳕半径ᵫ使ᶮᶫᶪᲿ(˜2 camera pixel)ᵶᵪᵶᵲᶍ半径ᶆᶎ2%-15%(seeingᶊᶧᶪ)ᶍfluxᵫᶡᶫᶅᵶᶝᵥᲿ
ᵲᶍ損失ᶱ補正ᵸᶪᵾᶠᶊcurve-of-growth correctionᶱ行ᵥᲿᵼᶍ補正後ᶍ値ᵫ
aperture等級ᶇᵶᶅ j̲m̲stdapᶉᶈᶊ記載ᵴᶫᶪ
curve-of-growth補正ᶱᵸᶪᵲᶇᶆᲾ4"-apertureᶍ測光ᶱ無限大-apertureᶍ測光ᶇ等価ᶊᵸᶪᲿ
単純ᶊ大ᵬᶉaperture半径ᶱ使ᵥᶇS/Nᵫ悪ᵮᶉᶪᶍᶆᵲᶍᶧᵥᶉᵲᶇᶱᵸᶪᲿ
2MASSᶆᶎseeing vs. curve-of-growth補正値ᶍtableᶱ参照ᵸᶪ
tableᶎ᷇ᷓᶂᶅᵣᶉᵣ明ᶪᵣ星ᶱ数多ᵮᲾᵣᶬᶲᶉseeing条件ᶆ複数aperture半径ᶆ測定ᵸᶪᵲᶇᶆempiricalᶊ作成
等級差ᵫ収束ᵸᶪ半径ᶱ決ᶠᶅ(次᷊ᷬ᳐図参照)Ჾᵼᶍ半径ᶆᶍ等級ᶇ4᳕半径ᶆᶍ等級ᶍ差ᶍmedianᶱ求ᶠᶪ(収束ᶍ条件ᶎᶈᵥᵶᶅᵣᶪᶍᵿᶬᵥᲿᲿ)各ᷢḅᷛᲾseeingᶆᶍinternalᶉconsistencyᶎmedianᶇmeanᶆ0.01等以下(?)

iii. Photometric Normalization
1.3s sec積分ᶆᲾS/Nᶍ高ᵣᲾ混ᶲᶆᵣᶉᵣᲾ᷇ᷓᶂᶅᵣᶉᵣ星ᶍcurve-of-growth補正後ᶍaperture測光値ᵫ2MASSᶍ真ᶍphotometric scaleᶱbestᶊ与ᵧᲾ
profile-fitting 等級ᶇ51-msᶆᶍaperture等級ᵫnormalizeᵴᶫᶪ• Profile-fit Photometry

normalizationᶎS/Nᶍ高ᵣ星ᶍprofile-fitting等級ᶇcurve-of-growth補正済ᶞ
aperture測光値ᶍ差ᵪᶨ求ᶠᶨᶫᶪᲿband毎Ჾseeing毎ᶊ差ᶍmedianᵫ
3-sigma clippingᵴᶫᶅ求ᶠᶨᶫᶪ
TileᶊᶧᶂᶅᶎᲾ星ᵫ少ᶉᵸᵭᵾᶩ
多ᵸᵭᵾᶩᵶᶅ信頼ᶆᵬᶪ値ᵫ得ᶨᶫ
ᶉᵣᲿ
ᵼᶍ場合ᶎtable (indexed by theseeing)ᶱ参照ᵸᶪᲿ• Bright Star Aperture Photometry
51-ms積分ᶆᶍ明ᶪᵣ星ᶍaperture測光値ᶎseeing look-up tableᶱ使ᶂᶅnormalizeᵸᶪ(51-msᶇ1.3secᶆ同時ᶊS/N良ᵮ測定ᶆᵬᶪ星ᶍ数ᶎ少ᶉᵣ)iv. Curve-of-Growth and Photometric Normalization Errors
最終的ᶉ2MASSᷙ᳐᷑処理ᵫ終ᶮᶂᵾᵡᶇᲾ星ᶍ数ᶍ少ᶉᵣ場所ᶇ多ᵣ場所ᶆᶍprofile-fitᶍnomalization
ᶊ対ᵶᶅ古ᵣ補正tableᵫ使ᶮᶫᶅᵣᵾᵲᶇᵫ判明ᵶᵾᲿsystematicᶊ明ᶪᵴᶱoverestimatedᵶᵾᲿ<0.01mag (good seeing)ᵪᶨ0.02-0.03mag(worst seeing)ᵲᶍbiasᶎcolorᶍ᷊᷵ḅᷩᶍ一要因ᶇᶉᶂᶅᵣᶪᷡ᷌
右図ᶎ銀河中心近ᵮᶍ3度x6度ᶍ領域ᶍH-Ksᶍmap
最大ᶆ0.05等ᶚᶈᶍH-Ksᶍ᷊᷵ḅᷩᵫᵡᶪ
ᶆᶡPSF-normalizationᶍerrorᵿᵰᶆᶎᵲᶍ値ᶎ説明ᶆᵬᶉᵣᲿ
ᶝᵿ2MASSᷓ᳐ᷲᶎᵲᶍ原因ᶱᶀᶢᶲᶇ理解ᵶᶅᵣᶉᵣ
ᶆᶡᲾᶈᵥᶡᲾprofile-fitᶍPSFᶍ変化ᶇ関係ᵫᵡᶩᵼᵥ
aperture photometryᶆᶎᵲᶍcolor biasᶎ出ᶉᵣᲿ• The Default Magnitude
上記ᶝᶆᶊ述ᶘᵾ各種方法ᶆ点源ᶍ測光ᵫ行ᶮᶫᵾ
default magnitude(j̲m, h̲m, k̲m)ᶆᶎ最ᶡᷫ᷋ᷚᶉᶡᶍᵫ選ᶏᶫᶅ記載ᵴᶫᶪ
rd̲flgᶊᶎᶈᶍ方法ᶱ使ᶂᵾᵪᵫ記載ᵴᶫᶪ
i. Non-Saturated ᳔Read2-Read1᳕ (J>9, H>8.5, Ks>8 mag)
Profile-fit photometry : rd̲flg= ᳔2᳕
Aperture photometry : rd̲flg= ᳔4᳕
ii. Non-Saturated ᳔Read1᳕ (4.5<J<9, 4<H<8.5, 3.5<Ks<8 mag)
Aperture photometry : rd̲flg= ᳔1᳕
iii. Saturated ᳔Read1᳕ (J<4.5, H<4, Ks<3.5 mag)
1-d Radial Profile Fitting : rd̲flg= ᳔3᳕
iv. Upper Limits
Non-Detections : rd̲flg= ᳔0᳕ᵼᶍᷢḅᷛᶆᶎ受ᵪᶂᶅᵣᶉᵣ場合Ჿupper limitᶎnoize levelᶍ2倍Inconsistently Deblended Sources : rd̲flg= ᳔6᳕ᶀᶢᶲᶇ分解ᵴᶫᶉᵪᶂᵾ多重᷏᳐᷋v. Detections with Failed Measurements (rd̲flg= ᳔9᳕)
technicallyᶊᶎ検出ᵴᶫᵾᵫᲾuseful measurementᶎᶆᵬᶉᵪᶂᵾᲿᷧ᷾᳐ᷲ
ᶍ端ᶍᶚᵥᶇᵪᲾdetectorᵫnoizyᶊᶉᶂᵾᶇᵬᶇᵪ

•
•
•
•
•
•
•

• Band Merging and Bandfills
ᶝᵹᶎ各ᷢḅᷛᶆ測光ᵴᶫᶪᶮᵰᶆᵼᶫᶨᶍᷰᷕᷓḅ᷂ᶱᵶᶉᵣᶇᵣᵰᶉᵣ
Jᶱ元ᶊJHᷬᶴᲾJKsᷬᶴᲾHᶱ元ᶊHJᷬᶴᲾHKsᷬᶴᲾKsᶱ元ᶊKsJᷬᶴᲾKsHᷬᶴᷰᷕᷓḅ᷂ᶎᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᲽᶱthresholdᶇᵶᶅ使ᵥᲿᷬᶴᶍseparationᶇ
位置ᶍ不確定性ᵫ変数
thresholdᶎ密度ᶊᶧᶩᲾ95,000 deg^-2ᶝᶆᶎ36.0Ჾᵼᵲᵪᶨ徐᳎ᶊ減ᶩᲾ350,000 deg^-2ᶆ
10.0ᶊᶉᶪ
i. Confusion in Band Merging
ᵡᶪᷢḅᷛᶍ1ᶃᶍ点源ᶊ2ᶃ以上ᶍ点源ᵫᷰᷕᷓᵶᵾ場合ᲾḶ^2ᶍ小ᵴᵣᷬᶴᶱ選ᶕᷰᷕᷓḅ᷂ᵫ非対称ᶉᵲᶇᶡᵡᶪᲿ(複雑ᶉ操作ᶱ繰ᶩ返ᵸᶨᵶᵣ)ii. Bandfills
他ᶍ1 or 2ᷢḅᷛᶆ検出ᵫ無ᵣ場合ᲾAtlas image上ᶍ相当ᵸᶪ場所ᶆ4᳕ aperturesizeᶆᶍfluxᶇnoiseᶍ測定ᵫᶉᵴᶫᶪᲿSkyᶎinner=14᳕, outer=20᳕
fluxᵫ検出ᵴᶫᶉᵣ場合Ჾnoise level ᶍ2倍(2-sigma)ᵫupper limitᶊᶉᶪᲿpositive fluxᵫ検出ᵴᶫᵾ場合Ჾᵼᶍflux +2-sigmaᵫupper limitᶊᶉᶪᲿᵼᶫᶨᶍ値ᶎdefault magnitudeᶊ記載ᵴᶫᶪ

• Optical Source Associations
2MASSᶍ位置決ᶠᶍreferenceᶎTycho 2ᶱ使ᵥᲿ
cameraᶍdistortionᶍᷴᷝ᷑᳐ᶊᶎ(星数ᶍ多ᵣ)USNO-A2.0ᶱ使ᵥ
2MASS PSC sourceᶍ5᳕以内ᶊᵡᶪoptical sourceᶎa=᳕T᳕(Tycho) or ᳔U᳕(USNOA)
ᶍflagᵫᶃᵬᲾᵼᶫᶨᶍ等級(b̲m̲opt and vr̲m̲opt)Ჾ離角(dist̲opt)ᶇ方位角(phi̲opt)ᵫ᷋ᷚ᷼ᵴᶫᶪᲿ
強調ᵸᶪᶍᶎᲾᵲᶫᶎpositional associationsᶆᵡᶂᶅᲾidentificationsᶆᶎᶉᵣᲿ
2MASSᶇoptical sourceᶍbest paringᶱ見ᶃᵰᶪ努力ᶎᵶᶅᵣᶉᵣᲿ
Tycho2ᶇᶍ比較ᶎᲾproper motionᶍ情報ᵫᵡᶪ場合ᶊᶎ位置ᶍ補正ᶱ行ᶂᶅᵣᶪ
USNO-A2.0ᶇᶍ比較ᶎproper motion補正ᶱᵶᶅᵣᶉᵣᲿ
Tycho2ᶍBᶇVᶍ等級ᶎJohnson systemᶊ変換ᵴᶫᶪ
V=Vt-0.090*(Bt-Vt), B-V=0.850*(Bt-Vt)
USNO-A2.0ᶍ等級ᶎᵼᶍᶝᶝ
Pole近ᵮ(¦dec¦ > 86度)ᶆᶍOPtical associationᶎᵡᶅᶊᶉᶨᶉᵣᲿ全然無ᵣᶇᵣᵥᶔᵥᶊ出ᶪᵫᲿ• Extended Source Identification and Photometry
省略•

Position Reconstruction
田辺ᵴᶲ

•

Artifact Identification
明ᶪᵣ星ᶊᶧᶂᶅᲾ人工的ᶉsourceᵫ作ᶨᶫᶪᲿ青 : Diffraction spike
赤 : Persistence image (北側ᶊ残ᶪ)᷎ᷰḅ᷒ : 明ᶪᵣ星ᶍwing᷉ᶴḅ : stripe (256᳕ northᶇsouth)ᷨ᷻ᶸḅ : Filter and Dichroic glint
緑: ᷼ᶴ᷽
黄: ᵾᶕᶲ᷼ᶴ᷽
人工的ᶉsourceᶎ明ᶪᵣ星ᶇᶍ位置関係Ჾ明ᶪᵴᵪᶨ判断ᵴᶫᶪflagᶃᵬᶆWorking Source Databaseᶗ
人工物ᶍ可能性ᶍ高ᵣᶡᶍᶎ最終的ᶉᶽ᷿᷂᷑ᶊᶎ
載ᶨᶉᵣ᷼ᶴ᷽ᶉ天体ᶇ思ᶮᶫᶪᵫᲾ明ᶪᵣ星ᶇᶍ位置ᶣ明ᶪᵴᵪᶨᲾartifactᶆᵡᶩ得ᶪᶡᶍᶊᶎcc̲flag(confusion and contamination flag)ᵫPSCᶍ中ᶆᶃᵰᶨᶫᶪcc̲flagᶎband毎ᶊᶑᶇᶃᵶᵪᶃᵪᶉᵣᲿ
2ᶃ以上ᶍflagᵫᶃᵮ場合ᶊᶎ下ᶍ表ᶆᶧᶩ上ᶊᵡᶪᶡᶍᵫ優先ᵴᶫᶪᲿi. Diffraction Spikes [cc̲flg= ᳔d᳕]明ᶪᵣ星(mthrDᶧᶩ明ᶪᵣ)ᶍ上下左右ᶊ出ᶪSpikeᶊᶧᶪ人工物
ᵼᶍSpikeᶊ重ᶉᶂᶅᵡᶪ明ᶪᵴᶧᶩᶡ暗ᵣᶡᶍ(mpar + ΔmD)ᶊᶎᵲᶍflagᵫᶃᵮSpikeᶍ長ᵴ : l = l0 * 10 ^[a * (m0´ - mpar) ] mparᶎ明ᶪᵣ星ᶍ等級
ᵲᵲᶆᲽm0´ = 6.0 - [ log10(src_dens/5883.0) / d ]Spikeᶍ幅 : w = w0 + (e * z) zは明ᶪᵣ星ᶇᶍ距離

ii. Persistence [cc̲flg= ᳔p᳕]
NICMOS3 arrayᶆᶎ明ᶪᵣ星ᵫ入ᶪᶇ続ᵮread outᶍᶇᵬᶊᶡ残ᶪ J<11.5, H<10.0, Ks< 9.5
出ᶅᵮᶪ位置ᶇ明ᶪᵴ形状(元ᶍ星ᵫRead1ᶆᶡ᷇ᷓᶪ場合)ᶆ判断ᲿᲽSIRIUSᶆᶎ出ᶉᵣᶍᶆ詳細ᶎ省略

iii. Filter and Dichroic GlintsᲽ(ᶽ᷿᷂᷑ᶊᶎ入ᶨᶉᵣ)
Glintᶎfilterᶇdichroic mirrorᵫ明ᶪᵣ星ᶱ反射ᵶᶅᶆᵬᶪ
point-likeᶉimage
明ᶪᵣ星ᶇᶍ位置関係Ჾ等級差ᵫ決ᶝᶂᶅᵣᶪᲿ
形状ᶎ星ᶊ見ᵧᶪᲿ
期待ᵴᶫᶪ位置(xgl = xpar+fgl , ygl = ypar+hgl )ᵪᶨrgl arcsec以内
ᶊᵡᶩᲾ等級ᵫmpar + ΔmG +/- σmgl ᶍ天体ᶱglintᶇᵸᶪᲿ

iv. Stripes [cc̲flg=᳔s᳕]
明ᶪᵣ星ᶇᵼᶍ上下256᳕ᶍᶇᵲᶬᶊ上下ᶍ幅8᳕ᶍ水平ᶉ線ᵫ出ᶪᲿ
電気的ᶉᶡᶍᶆᲾJ<6.7, H < 6.2, Ks < 5.7 magᶍᶇᵬᶊᶆᶪᲿ
v. Bright Star Confusion Artifacts
᷇ᷓᶪ星ᶍcoreᶍ中ᶣ外ᶊᶎfaulse detectionᵫ現ᶫᶪᲿ
ᵼᶫᶨᵫ現ᶫᶪ半径ᶱartifact confusion radiusᶇᵸᶪᲿᵼᶍ半径内ᶊᵡᶪ場合ᲾR2-R1ᶆrd̲flg=2, R1ᶆrd̲flg=1ᶍ᷂ᷧ᷻ᵫᶃᵮᲿ
riAC = r0AC * 10^[ b * ( mi0AC - mpar ) ]vi. Photometric Confusion [cc̲flg= ᳔c᳕]᷇ᷓᶂᵾ星ᶍ周ᶩᶊᵡᶪ᷼ᶴ᷽ᶉ星ᶎ等級精度ᶊ影響ᶱ受ᵰᶪᲿ
5%以上ᶍ等級誤差ᶱ受ᵰᵾ᷏᳐᷋ᶊᶎ᷂ᷧ᷻cc̲flg=cᵫᶃᵮphotometric confusion radiusᵫ以下ᶍᶧᵥᶊ計算ᵴᶫᶪ
rPC = r0PC * 10^ [c * (mfs - mpar) ]ᵲᵲᶆ mfs ᶎ᷇ᷓᶂᵾ星ᶍᵼᶏᶍ星ᶍ等級Ჿ

ᵼᶍ他
虫(左)
OH(右)

•

Photometric Calibration
2MASS Atlas imagesᶍFITSᷪᷕ᷒ᶊᶎ測光ᶍ᷎᷿点ᲾmagzpᲾᵫ記載ᵴᶫᶅᵣᶪᲿ
ᵲᶍ章ᶆᶎᶈᵥᶣᶂᶅᵼᶍ᷎᷿点ᶱ求ᶠᵾᵪᵫ記述ᵴᶫᶅᵣᶪᲿ
instrumental magnitudeᶇcalibrated magnitudeᶍ変換ᶎᲾ
Mcal = Minst + c1 - c2(X-1.0)
c1 : photometric zeropoint offset (mag)c2 : extinction coefficient (mag/airmass)
X : airmassᶡᶀᶬᶲᷢḅᷛ毎ᶊ違ᵥ係数Ჿ
a. Instrumental Magnitudes
Minst = M0,inst -2.5*log10(counts) + Knorm
M0,inst : ᵩᵩᶧᵼᶍzero点ᶍ平均値Ჿ固定ᲿKnorm : the curve-of-growthᶍ補正値

b. Photometric Zeropoint Evaluation
photometric zero point offset coefficient c1ᶎ大気ᶍ透過率ᶱ反映
c1(J,H,Ks)ᶎ夜毎ᶊ評価ᵴᶫᲾᵼᶍ夜ᶍ間ᶍ時間ᶍ関数ᶇᵸᶪᵼᶫᵽᶫᶍcalibration frameᶆᲾᵼᶍ時ᶍzero point offsetᵫ計算ᵴᶫᶪᲿᲽᲽᶃᶝᶩᲾ標準星ᶍᶽ᷿᷂᷑値(Mcat)ᶇ吸収補正ᵶᵾMinst᳓=Minst-c2(X-1.0)ᲽᲽᲽᲽᲽᲽᵲᶍoffsetᶊᶎ標準星ᶍcurve-of-growth補正済ᶞᶍ値ᵫ用ᵣᶨᶫᶪ
HᶇKsᶍc1ᶎ時間ᶍ1次関数ᶆleast-square fitᵴᶫᶪᲿJᶎ頻繁ᶊ変ᶮᶪᶍᶆᲾcalibration毎ᶊlinear interpolationᵸᶪᲿ例ᵧᶏᲾ1999/11/11ᶍ例Ჿ横軸時間Ჾ縦軸Mcat-Minst᳓

Jc1(H,T) = b b b 0.0267 - 0.0021 * T(hr)H

c1(Ks,T) = bbb 0.0699 - 0.0003 * T(hr)Ksc. Extinction Coefficients
airmass補正ᶍc2ᶎlook-up tableᶱ用ᵣᶪᲿ観測所ᶇ月ᶆindexᵴᶫᶅᵣᶪᲿ
2MASSᶍ2次標準星ᶽ᷿᷂᷑ᶱ作成ᵸᶪᶇᵬᶊ月毎ᶍ平均吸収補正係数ᵫ求ᶠᶨᶫᵾᲿ
ᶝᵹ各標準星ᶊᶃᵣᶅ600-3500ᶍ測定ᶱ用ᵣᶅᲾ各夜ᶍ測光解ᶱ求ᶠᵾᲿ
次ᶊairmass補正ᶉᵶᶆ標準星ᶍᶽ᷿᷂᷑値ᶇ測定値ᶍ差ᶱ求ᶠᵾᲿ
月毎ᶊairmass対上記ᶍ差ᶍfitᶱ作成Ჿ傾ᵬᵫairmass補正係数ᶇᶉᶪᲿd. Calibration Uncertainties
combined photometric uncertaintiesᶎPSCᶆᶎᲾj̲msigcom ...
夜毎ᶍHᶇKsᶍlinear fitᶍRMS残差ᶎcalibrationᶍ精度ᶍ目安ᶆᵡᶩᲾ
平均ᶆ0.005-0.006magᶆᵡᶪᲿᵾᶝᶊ(a few nights)0.01 magᶱ超ᵧᶪ
ᵾᵿᵶᲾᵲᶫᶎsurveyᶍ精度ᶱ表ᵶᶅᵣᶉᵣᵶᲾJᷢḅᷛᶊᶃᵣᶅᶎᵼᶍ残差ᶎ求ᶠᶨᶫᶉᵣᲿ
ᶡᵥᶀᶦᶂᶇ厳ᵶᵣᶣᶩ方ᶆ求ᶠᶪᲿᵡᶪcalibration fieldᶱ ᳔a test particle᳕ᶇᵸᶪᲿ
ᵼᶫ以外ᶍcalibration fieldᵪᶨphotometric solutionᶱ求ᶠᶪ᳔a test particle᳕ᶍfieldᶍ残差ᶱ求ᶠᶪᲿ
ᵲᶫᶎworst-case errorᶊᶉᶪᲿ前後ᶍcalibration fieldᶍ観測ᶎ2倍長ᵮ
時間ᵫ明ᵣᶅᵣᶪᶍᶆᲿ
結果Ჾ残差ᶍRMSᶎJ,H,Ks ᶆ0.011, 0.007, 0.007 mag• Known Asteroid, Comet, Planet, and Satellite
Associations

ᵲᶫᶨᶍ太陽系天体ᶊᶎmp̲flg=1ᵫᶃᵮᲿ
位置推算表ᶱ利用ᵶᶅ同定
小惑星ᶎ右ᶍ図ᶍᶧᵥᶉcolorᶨᵶᵣ• Quality Assurance (QA)
最終的ᶉᷙ᳐᷑ᵫ最初ᶍ要求 ᳔Level 1 specifications᳕ (次頁参照)ᶱ満ᵾᵶᶅᵣᶪᵪ
Survey中ᶎᶈᶍTileᶎ᳢済ᶞ᳣ᶆᶈᶍTileᶎ᳢要再観測᳣ᵪᲾᶍ評価
最終ᶽ᷿᷂᷑ᶍᷙ᳐᷑ᶍqualityᶍ評価
QAᶊᶎ3᷋ᷘᷕᷩᵡᶪ

• 第1᷋ᷘᷕᷩᶎᲽ᳔24-hr QA᳕ ; IPACᶊᷙ᳐᷑ᷘ᳐ᷩᵫ届ᵣᶅᵪᶨ24時間以内ᶊ行ᶮᶫᶪᲿ
quick checkᶱᵶᶅ機械ᶍ具合ᶍᷓᶹᷕ᷁ᶇ明ᶨᵪᶊ悪ᵣᷙ᳐᷑ᶍ確認(再観測ᶍᵾᶠ)• 第2᷋ᷘᷕᷩᶎᲽ᳔Nightly Science QA᳕ ; preliminary pipelineᶱ通ᵶᵾᷙ᳐᷑ᶍ詳細ᷓᶹᷕ᷁

• 2MASS全ᷙ᳐᷑処理後ᶊpipelineᶎ改善ᵴᶫᵾᲿNightly Science QAᶆ ᳔3᳕以上ᶍ᷋᷅ᶴᶍᷙ᳐᷑ᷕᷚ᷍ᶊᶃᵣᶅᶎᲾᵼᶍfinal pipelineᶆ再処理Ჿ ᳔Final Science QA᳕ᶱ行ᵥ

QAᶆᶎLevel 1 specificationsᶱ満ᵾᵶᶅᵣᶪ程度(likelihood)ᶱ10点満点評価ᵸᶪᲿᵲᶍ点数ᶎ以下ᶍᶧᵥᶊ診断ᵴᶫᶪ

• 観測時ᶍ空ᶍ測光ᶍ質ᶇᲾ ᳔我᳎᳕ᵫᵼᶫᶱᶀᶢᶲᶇ見積ᶡᶫᵾᵪ• ᷙ᳐᷑ᶍ感度ᶇsky backgroundᶍ安定度• seeingᶇᲾ᳔我᳎᳕ᵫseeingᶍ変動ᶱᶀᶢᶲᶇ見積ᶡᶫᵾᵪ• 位置精度Survey Level 1 Requirements

以下ᲾFinal Science QAᶍ詳細• Photometricity
calibration scanᶆᶍ6回ᶍ測光ᶍ平均ᵪᶨᶍᶏᶨᶃᵬᵫ測光ᶍ安定性ᶍ最初ᶍ診断
calibration fieldᶍ測光᷎᷿点fitᶍᶏᶨᶃᵬᵫ2番目ᶍᷓᶹᷕ᷁(by eye!)

0.1 mag

隣ᶍscanᶇ重ᶉᶪᶇᵲᶬᶊᲾS/N > 20ᶍ明ᶪᵣ星ᵫᵡᶫᶏ等級ᶍ違ᵣᶱ
ᷓᶹᷕ᷁(by eye!) 下ᶍ図上記ᶍ診断ᶱᵶᶅᲾphotometric quality factor; fct1=pfct1*pfct2*pfct3ᵫ計算ᵴᶫᶪᲿ• pfct1 : calibration scan setᶍ数ᵫ5以下ᶊᶉᶪᶇ質ᵫ悪ᵣᶇ考ᵧᶪᲿ
5-6:pfct1=1.0, 4:pfct1=0.9, 3:pfct=0.8, 2ᶍᶇᵬᶎ次ᶍpfct2=pfct3=1.0ᶍᶇᵬᶍᶞ
pfct=0.3ᶱ与ᵧᶪᲿᵼᶫ以外(non-photometric)ᶎᲾpfct1=0.0• pfct2 : calibration scan ᶆᶍ6回ᶍ測定ᶍᶏᶨᶃᵬᲿ

•分散ᵫ0.04等以下ᶍᶇᵬ : pfct2=1.0
分散ᵫ0.04等以上ᶍᶇᵬ : pfct2=2 - ((worst dispersion)/0.04 mag)airmass > 1.5ᶍᶇᵬᵿᵰ大ᵬᶉ分散ᶱ示ᵶᶅᶅ他ᶎphotometricᶉᶇᵬᶊᶎpcft2ᶍ᳢格下ᵱ᳣ᶎᵶᶉᵣ
pfct3 : 重ᶉᶪ部分ᶆᶍ同ᵷ星ᶍ等級差
peak-to-peakᶆ0.05等以下 : pfct3=1.0
0.050-0.075等 : pfct3=0.7
0.075-0.100等 : pfct3=0.4
0.100等以上 : pfct3=0.0ᵾᶝᶊ重ᶉᶪ部分ᵫᶉᵣᶇᵬᶡᵡᶪᲿᵼᶍᶇᵬᶎ後述ᶍbackgound levelᶱ雲ᵫ存在ᵶᵾᵪᶈᵥᵪᶍ指標ᶊᵸᶪ• 他ᶍphotometricityᶍᷓᶹᷕ᷁
PSFᶍσᶱPSFᲽmagnitudeᶍ関数ᶇᵶᶅ計算ᲾḶ^2ᶱmagnitudeᶇ
detector上ᶆᶍ位置ᶍ関数ᶇᵶᶅ計算Ჿ
PSF ᶇ aperture 測光ᶍ差ᶱmagnitudeᶇdetector上ᶍ位置ᶍ関数ᶇᵶ
ᶅ計算Ჿ明ᶪᵣ星ᶇ暗ᵣ星ᶇᶆᶈᵥ違ᵥᵪ
R1 aperture magnitude ᶇ R2-R1 PSF-fit magnitudeᶍ差• Sensitivity/Backgrounds (Airglow)/Meteor Blanking
photometric sensitivity parameter (PSP) ᶇᵣᵥᶍᵫscanᵳᶇᶊ計算ᵴᶫᶪPSPᶎᲾseeingᶇbackground levelᵪᶨ期待ᵴᶫᶪS/N=10限界等級ᶱ導ᵮᲿ
S/N=10ᶍ限界等級(M10)ᶇbackground level (BG)ᶊᶎ相関ᵫᵡᶪM10 Ჽ= k BG^1.5
seeing shape (SH : FWHM = 3.13*SH-0.46) ᶇᶡ相関ᵫᵡᶪᶃᶝᶩseeingᵫᶧᵮᶅbackgroundᵫ
低ᵰᶫᶏ感度ᶎᶧᵮᶉᶪ(当ᵾᶩ前ᵿᵫ)PSP=SH*BG^0.29ᶎS/N=10ᶍ限界
等級ᶍindicatorᶇᶉᶪᵲᶍPSPᶍ値ᶱ元ᶊfct2ᶇᵣᵥ
sensitivity quality parameterᶱ計算ᵸᶪᲿ 要求ᶱ満ᵾᵶᶅᵣᶪ可能性backgroundᲽ levelᶍ変化ᶡᷓᶹᷕ᷁雲ᵫ来ᵾ例• Cnoise(4)OH glowᶍ急激ᶉ変化ᶊᶧᶂᶅᲾ᷋ᶽᶶᶊᶍᶪᷣ᷑᳐ḅbackground levelᵪᶨ期待ᵴᶫᶪnoiseᶇ実際ᶍnoiseᶇᶱ比較ᵶᶅ
ᵲᶍflagᶱᶃᵰᶪCnoise(4)ᶱᶡᶇᶊairglow quality factor, fct5 ᶱ決ᶠᶪ
Cnoise(4) < 4.5 : fct = 1.0
Cnoise(4) > 4.5 : fct = 0.1• jump counter

frameᶍbackgroundᵫ隣ᶍframeᶍbackgroundᶍ平均ᶧᶩᶡ
0.5 x root-sum-squared noise 分以上違ᶂᶅᵣᵾᶨsky levelᵫ
急激ᶊ変化ᵶᵾᶇᶞᶪ
airglowᶍ変化Ჾ雲Ჾ電気系ᶍ異常ᶱᶇᶨᵧᶪ• QAᶍ段階ᶆᶎᲾ流星Ჾ人工衛星ᶉᶈᶍ1ᶃᶍᷧ᷾᳐ᷲᶊᵶᵪ出ᶉᵣᶡᶍᶎᵼᶡᵼᶡ取ᶩ除ᵪᶫᶅᵣᶪᲿ
QA係ᶍ人ᶎᵼᶫᶨᵫ本当ᶊtransientᶉᶡᶍᶉᶍᵪᲾ取ᶩ除ᵮ事ᶆᶀᶢᶲᶇ
得ᵶᵾᵪᲾᶱ見ᶅ調ᶘᶪᲿ幸運ᶉᵫᶨᲾ変ᶉ残ᶩ物ᶎ少ᶉᵪᶂᵾᲿ

• Seeinghigh qualityᶍ条件ᶇᵶᶅᲾseeingᵫᵡᶪ程度小ᵴᵣᲾ星ᵫ丸ᵣᲾpipeline自体ᵫseeingᶍ変化ᶧᶩᶡ早ᵮseeing測定ᶱ追ᵣᵪᵰᶪᲾᵲᶇᵫ重要• overall seeing : seeingᶎJᷢḅᷛᶆ一番悪ᵣᲿseeing shape quality factor, fct3
Jᶍseeing shape ᵫ最大ᶆ1.3以上(3.61᳕)ᵪ平均ᵫ1.25以上ᶉᶨfct3=0.1• PSF elongation : 丸ᵴᶎ a second image moment ratioᶆ測ᶪ
丸ᵣᶇ1ᶆᵡᶪᲿᵲᶫᵫ0.81ᶱ下回ᶪᶇ最終的ᶉgrade(後述)ᶱ1下ᵱᶪ

• Tracking of seeing variations : 900᳕ᶍ長ᵴ以上ᶊᶮᵾᶂᶅᲾseeingᵫ追ᵧᶅᵣ
ᶉᵣ場合Ჾuntracked seeing quality factor, fct4=0.1ᶇᵸᶪ

• Astrometry• overlapᵶᵾframe間ᶆᶍastrometric solutionᶍ比較Ჿ違ᵣᵸᵭᶅᶉᵣᵪᲿ• Global astrometry : Tycho catalogᶇᶍ比較• R1ᶇR2-R1ᶆ᷌᷾ᶎᶉᵣᵪ• distortionᶍᷴᷝ᷑᳐ : USNO-Aᶇᶍ比較• Scientific Diagnostics : astrophysicalᶉ観点ᵪᶨᶍᷓᶹᷕ᷁
• Color-colorᶇcolor-magnitude図ᶆᶍᷓᶹᷕ᷁Ჾ銀緯ᵳᶇᶮᵰᶅᲾdwarfᶇ
giantᶍlocusᶇ比較ᵶᶃᶃᲾ変ᶉᶍᵫᶉᵣᵪ• colorᶇdetectorᶍx- y- ᶍ位置ᶇᶊ相関ᶎᶉᵣᵪ᳅• Color-colorᶇcolor-magnitude図ᶆR1ᶆᶡ᷇ᷓᶂᵾ星ᶍ色ᶇ等級ᶍᷓᶹᷕ᷁
• Miscellaneous Diagnostics• 小惑星ᶍflagᶍᷓᶹᷕ᷁
• the final processᶇthe preliminary processᶍ違ᵣᶱᷓᶹᷕ᷁
ᵣᵪᶊᵶᶅᵼᶍ差ᵫ生ᵷᵾᵪᶱ把握

• Final Quality Scoring• 上記ᶍᷓᶹᷕ᷁ᶍqualityᶍ総計• grade = 10 * min(fct1, fct2, fct3, fct4, fct5)