ALMA Cycle 5 Technical Handbook

218 Pages·2017·52.25 MB·English

Doc 5.3, ver. 1.0 | March 21, 2017
ALMA Cycle 5 Technical Handbook
ALMAisapartnershipofESO(representingitsmemberstates),NSF(USA)andNINS(Japan),togetherwithNRC
(Canada),NSCandASIAA(Taiwan),andKASI(RepublicofKorea),incooperationwiththeRepublicofChile.
TheJointALMAObservatoryisoperatedbyESO,AUI/NRAOandNAOJ.
2
User Support
Forfurtherinformationortocommentonthisdocument,pleasecontactyourregionalHelpdeskthroughtheALMAUser
Portal at www.almascience.org. Helpdesk tickets will be directed to the appropriate ALMA Regional Center at ESO,
NAOJorNRAO.
Revision History
Cycle Version Date Editors Remarks
1 1.0 2013-10-01 A. Hales, A. Lundgren, A. Biggs,
J. Di Francesco, B. Vila Vilaro,
S. Leon, D. Barkats, E. Fomalont,
S.Asayama,S.Komugi
2 1.1 2013-10-15 A. Lundgren, S. Leon, J. Hibbard,
E.Müller,J.DiFrancesco
3 1.0 2015-03-20 A.Remijan,M.Adams,R.Warmels Cycle3
4 1.0 2016-03-22 J.MangumandR.Warmels Cycle4
4 1.1 2016-09-07 J.MangumandR.Warmels Replacefigs7.9and7.10
5 1.1 2017-03-21 R.WarmelsandA.Remijan Cycle5
Editors
ReinWarmelsandTonyRemijan
Authors of this Edition
Itziar de Gregorio - Chapter 1; Antonio Hales - Chapter 2 and Appendix A; James Di Francesco - Chapter 3;
GianniMarconiandBillDent-Chapter4;SeijiKameno-Chapter5;BillDent-Chapter6;EricVillard-Chapter
7; Baltasar Vila Vilaro - Chapters 8 ,11 and 12; Andy Biggs - Chapter 9; Ed Fomalont - Chapter 10; John
Hibbard-Chapter13;FelixStoehr-Chapter14;Shin’ichiroAsayama-AppendixB
Contributors to this Edition
Eiji Akiyama, Rodrigo Amestica, Yiping Ao, Yanett Contreras, Todd Hunter, Woojin Kwon, Mark Lacy, Har-
vey Liszt, Jeff Mangum, Brian Mason, Ralph Marson, Rie Miura, Arielle Moullet, Jennifer Donovan Meyer,
HiroshiNagai,KouichiroNakanishi,Se-HeonOh,RositaPaladino,AnitaRichards,RachelRosen,KazyRygi,
Kamaljeet Saini, Richard Simon, Gie-Han Tan, Ken Tatematsu, Carmen Toribio, Lance Utley, Catherine Vla-
hakis,AlWootten,KijeongYim,LlsangYoon
Inpublications,pleaserefertothisdocumentas:
ALMAPartnership,2017,S.Asayama,A.Biggs,I.deGregorio,B.Dent,J.DiFrancesco,E.Fomalont,
A.Hales,J.Hibbard,G.Marconi,S.Kameno,B.VilaVilaro,E.Villard,F.Stoehr
ISBN 978-3-923524-66-2
Contents
1 Introduction 9
2 Array Components 11
2.1 The ALMA Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.2 The 12-m Array. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3 The Atacama Compact Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.3.1 The 7-m Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.3.2 The TP Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3 Principles and Concepts of Interferometry 15
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.2 Single-dish Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.3 Visibilities and Aperture Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.4 The Visibility or uv-Plane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.5 Fields-of-view and Mosaics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.6 Spatial Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.7 Multi-configuration Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.8 Units and Conversions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4 Receivers 31
4.1 Local Oscillators and IF Ranges. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
4.2 The Cycle 5 Receivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
4.2.1 Band 3 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
4.2.2 Band 4 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.2.3 Band 5 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.2.4 Band 6 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.2.5 Band 7 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
4.2.6 Band 8 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4.2.7 Band 9 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.2.8 Band 10 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
5 The Correlators 59
5.1 The 64-input Correlator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
5.1.1 TDM mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
5.1.2 FDM mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
5.1.3 Correlation and Realtime Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
5.2 The ACA Correlator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
5.2.1 The 7-m Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
5.2.2 The Total Power Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
5.3 Digitizers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
5.4 Online WVR Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
5.5 Capabilities of the Correlators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
5.5.1 Polarization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
3
4 CONTENTS
5.5.2 Spectral Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
5.5.3 Time Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
5.5.4 Phase Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
5.6 Practical Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
5.6.1 Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
5.6.2 Linearity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
5.7 Final data product - the ASDM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
6 Spectral Setups 75
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
6.2 Frequency Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
6.3 Spectral Setups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
6.3.1 Observing Frequencies for Continuum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
6.3.2 Multiple Spectral Windows in the Same Baseband . . . . . . . . . . . . . . . . . . . . . . 80
6.3.3 Spectral Setups for Lines near the Edge of the Bands . . . . . . . . . . . . . . . . . . . . 81
6.3.4 Spectral Setup in Bands 9 and 10: DSB Considerations and 90-degree Phase Switching . 81
6.4 Usable Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
6.5 Spectral Resolution and Channel-averaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
6.6 Spurious Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.7 Doppler Setting and Velocity Reference Frames . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.8 Limitations and Rules for Spectral Setups in Cycle 5 . . . . . . . . . . . . . . . . . . . . . . . . . 84
7 Imaging with ALMA 87
7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
7.2 Cycle 5 Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
7.3 Shadowing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
7.4 Resolution and Beam Shape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
7.5 Response and Snapshot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
7.6 Spatial Scale Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
7.7 Mosaicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
7.8 Multi-array and Multi-configuration Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
7.9 Multi-array and Multi-configuration Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
8 Observing Modes 109
8.1 Observing Project Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
8.2 Program Execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
8.3 The Observing Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
8.3.1 The Source Selection Algorithm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
8.4 Single Field Interferometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
8.5 Pointed Mosaic Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
8.6 Single Dish (Total Power) Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
8.7 Polarization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
8.7.1 Sessions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
8.8 Multiple Region Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
8.9 Observation of Ephemeris Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
8.10 Solar Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
8.10.1 Solar Observing Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
8.10.2 Array Observations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
8.10.3 Single Dish Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
8.11 VLBI Observing Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
8.11.1 General VLBI Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
8.11.2 ALMA Considerations for VLBI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
8.12 High Frequency Observing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
CONTENTS 5
9 ALMA Sensitivity Calculator 131
9.1 Calculating the System Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
9.1.1 Sky Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
9.1.2 CMB Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
9.1.3 Receiver Temperatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
9.1.4 Ambient Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
9.1.5 DSB Receivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
9.1.6 System Temperature (OT version) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
9.1.7 System Temperature (Stand-alone ASC and GUI (OT) version) . . . . . . . . . . . . . . . 136
9.2 The Sensitivity Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
9.2.1 12-m and 7-m Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
9.2.2 Total Power Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
9.3 User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
9.4 Total Time Estimates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
10 Calibration and Calibration Strategies 141
10.1 The True and Observed Visibility Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
10.1.1 The Data Format and the Correlator Model . . . . . . . . . . . . . . . . . . . . . . . . . . 141
10.1.2 The Visibility Function Dependence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
10.2 Main Interferometric Calibration Strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
10.2.1 Phase Referencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
10.2.2 Antenna-based Calibrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
10.2.3 Major Calibrations Affecting Interferometric Data . . . . . . . . . . . . . . . . . . . . . . 143
10.2.4 The Organization of the Calibrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
10.3 ALMA-Supplied a-priori Calibrations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
10.3.1 Antenna Beam/Surface Characteristics (P) . . . . . . . . . . . . . . . . . . . . . . . . . . 144
10.3.2 Antenna Pointing Models (P) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
10.3.3 Focus Models (P). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
10.3.4 Antenna Delay Offsets (D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
10.3.5 Antenna Positions (M) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
10.4 On-Line Calibrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
10.4.1 Water Vapor Radiometer Measurements (M) . . . . . . . . . . . . . . . . . . . . . . . . . 147
10.4.2 System and Receiver Temperature(T) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
10.4.3 Additional Antenna Pointing Checks (P). . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
10.5 Off-Line Calibrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
10.5.1 On-Line Flagging (F) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
10.5.2 Calibration-based Flagging (F) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
10.5.3 Bandpass Calibration (B) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
10.5.4 Gain Calibration (G). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
10.5.5 Flux Density Calibration (T) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
10.5.6 Polarization Calibration (p,X) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
10.6 Additional Calibration Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
10.6.1 Observations at Frequencies >400 GHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
10.6.2 Observations with Baselines >3 km . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
10.6.3 Phase Calibration with Narrow Bandwidths . . . . . . . . . . . . . . . . . . . . . . . . . . 153
10.6.4 Band-to-Band Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
10.6.5 Check Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
10.6.6 Astrometric Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
10.6.7 Self-Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
10.6.8 Total-Power Calibrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
10.6.9 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
6 CONTENTS
11 Quality Assurance 157
11.1 Cycle 5 Quality Assurance Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
11.2 QA0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
11.3 QA1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
11.4 QA2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
11.5 QA3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
11.6 The Quality Assurance Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
11.7 QA Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
12 Data Flow and Logical Data Structure 163
12.1 Data and Control Flow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
12.2 The ALMA Science Data Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
13 Pipeline Processing 169
13.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
13.2 Pipeline In ALMA Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
13.2.1 Standard and Non-standard Observing Modes. . . . . . . . . . . . . . . . . . . . . . . . . 169
13.2.2 Pipeline Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
13.2.3 Pipeline Runs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
13.3 Details on Pipeline Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
13.3.1 Pipeline Runtime Database Queries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
13.3.2 Observatory “Fixes” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
13.3.3 Flagging Heuristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
13.3.4 Treatment of Multiple Execution Observations . . . . . . . . . . . . . . . . . . . . . . . . 175
13.3.5 Low SNR Heuristics in Interferometric Pipeline Processing . . . . . . . . . . . . . . . . . 175
13.3.6 Total Power Pipeline Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
13.3.7 Imaging – interferometric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
13.4 Pipeline and the ALMA Quality Assurance Process . . . . . . . . . . . . . . . . . . . . . . . . . . 176
13.5 Output of the Pipeline Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
14 Data Archiving 179
14.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
14.2 Data Flow and Archive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
14.3 PI Data and Data Delegation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
14.4 Archive Query . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
14.5 Request Handler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
A Antennas 185
A.1 Design and Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
A.2 Antenna Foundations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
A.3 Antenna Transportation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
A.4 Cryostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
A.5 Amplitude Calibration Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
A.5.1 Atmospheric Calibration Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
A.6 Water Vapor Radiometers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
B The LO and IF System 197
B.1 Functions of the LO and IF System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
B.2 Summary of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
B.3 Frequency Generation and Distribution in ALMA . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
B.3.1 Reference and LO Signal Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
B.3.2 LO1 Signal Generation and Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
B.3.3 Line Length Corrections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
B.3.4 The First Local Oscillator (LO1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
B.3.5 LO2 and the IF Processor Units and IF Switch . . . . . . . . . . . . . . . . . . . . . . . . 204
CONTENTS 7
B.3.6 Digitization and Signal Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
B.4 Other functions of the LO/IF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
B.4.1 Delay Corrections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
B.4.2 Sideband Suppression - LO Offsetting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
B.4.3 Interference Rejection - 180 degree Phase Switching . . . . . . . . . . . . . . . . . . . . . 207
B.4.4 Sideband Separation - 90 degree Walsh Switching . . . . . . . . . . . . . . . . . . . . . . . 207
C Acronym Dictionary 209
8 CONTENTS
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Chapter 1
Introduction
TheAtacamaLargeMillimeter/SubmillimeterArray(ALMA)isanaperturesynthesistelescopeconsistingof66
antennasarrangedinaseriesofdifferentconfigurations. Itoperatesoverabroadrangeofobservingfrequencies
inthemillimeterandsubmillimeterregime. ALMAEarlyScienceOperationsstartedwithCycle0inSeptember
2011 and the official inauguration took place in March 2013.
Cycle 5 operations will include standard and non-standard observing modes. Non-standard modes are
observing modes for which the data cannot be processed by the pipeline and need to be reduced manually by
ALMA staff. Up to 20% of the PI observing time in Cycle 5 will be allocated to proposals requesting non-
standard modes. Users should refer to Appendix A (ALMA Capabilities) in the ALMA Cycle 5 Proposer’s
Guide, for the latest information and a description of standard and non-standard modes.
The Technical Handbook provides additional information on technical aspects and their limitations of the
Cycle 5 setup for ALMA users. It should, however, not be necessary to use the Technical Handbook to prepare
an ALMA proposal.
Thehandbookisdividedintothreemainsections: TheconceptsofinterferometryandtheALMAhardware
components (Chapters 2–5), the observing concepts and software (Chapters 6–9), and finally the data quality
and handling (Chapters 10–14). It also includes a number of appendices with expanded information on specific
ALMA hardware components and calibration, and an acronym list.
Chapter 2 describes the ALMA Array components: The 12-m Array and the Atacama Compact Array
(ACA),alsoknownastheMoritaArraywhichiscomprisedofthe7-mandTotalPower(TP)Arrays. Ageneral
description on the different array elements and their components is provided.
Chapter 3 gives a briefintroduction to interferometry, including a description on the concepts ofbasic radio
astronomy and the principles of aperture synthesis.
Chapter 4 describes the details of the seven receivers offered in Cycle 5. The general technical specifications
and a brief explanation on local oscillators and IF range is presented. Plots with the atmospheric transmission
and the typical system temperatures per receiver are also included.
Chapter 5 describes the correlators and the data processing taking place in these special purpose supercom-
puters. A description of the 64-input Correlator (used for the 12-m Array) and the ACA Correlator (used by
the 7-m and the TP Arrays) is provided. Modes for continuum and spectral line observations are presented.
Chapter 6 describes how the spectral setup is done in the correlators. It covers a description of the signal
pathandlocaloscillatorchainusedbetweenthefrontendsandthecorrelators, andhowtheseareusedtodefine
spectral setups for the user.
Chapter 7 describes several aspects of imaging to consider in ALMA observations. A short description on
the different configurations proposed for Cycle 5 is included. Concepts of shadowing, beam shape, and spatial
scale filtering are revisited. Mosaicing, and 12-m and 7-m Array data combination are also presented.
9
10 CHAPTER 1. INTRODUCTION
Chapter 8 describes the observing modes offered for Cycle 5 and how projects are observed. Single field in-
terferometry,mosaics,single-dishobservations,polarization,multipleregionmodes,solar,VLBI,andephemeris
observations are detailed in this section.
Chapter 9 gives a brief overview how sensitivities and integration times are calculated at ALMA.
Chapter 10 describes how calibration is performed at ALMA, providing a description on how to calibrate
long-term and short-term effects as well as how calibrators are selected.
Chapter 11 describes the data quality assurance process. It also provides the criteria used for passing the
quality assurance.
Chapter 12 describes the structure of the data.
Chapter 13 includes a description on the ALMA pipeline, its infrastructure, the pipeline heuristics and the
use of the pipeline in data calibration.
Chapter 14 describes how the data are stored, the data flow and the ALMA Archive.
The Technical Handbook concludes with two appendices, which contain supplemental material about the
antenna design and transportation transporter (Appendix A), and the Local Oscillator (LO) and Intermediate
Frequency (IF) system (Appendix B).
Figure 1.1: ALMA antennas on the Chajnantor Plateau.
Credit: ALMA (ESO/NAOJ/NRAO), O. Dessibourg