Technical justification(and Control and Performance)

tips

Kouichiro Nakanishi(EA-ARC, NAOJ)

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References• Detailed guideline is given in Proposer’s Guide(PG)– section 5.3 and Appendix B• Supporting materials– OT Reference Manual/video tutorial– Technical Handbook– Knowledgebase articles

2Technical justification• is entered directly into OT in the TJ node ofeach ScienceGoal• must include a quantitative description andjustification of the expected source
brightness, the requested sensitivity and S/Nratio, angular resolution and spectral setup• must be self-contained– figures can be included in Science Justification PDF• three major sections: sensitivity, imaging,correlator configuration

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Sensitivity• explain which sensitivity or S/N are expected
for all the parts of the spectrum that are ofinterest, and the means by which theproposed technical setup will achieve thoserequests

4Sensitivity• enter values with care in other sections (“FieldSetup”, “Control and Performance”, etc)
prior to enter Technical Justification texts– OT will display warning(s) about potentiallyproblematic setup(s)6Blue warningpotentially problematic setups

The PI have to modify the setup and/or justify it7

Blue warningpotentially problematic setups• Potentially problematic setups OT will warn
– Signal-to-Noise ratio (S/N) < 3– bandwidth for sensitivity >1/3 of line width– spectral resolution > 1/3 of line width• a project aiming to study kinematics with a spectral line

– very high spectral dynamic range• highly band dependent, see Proposer’s Guide A9.3

• PI have to modify the setup and/or justify it,otherwise it may lead to a rejection(technically unfeasible)

8Spectral Dynamic Range

BandLimit

345678910

1000 1000 500 1000 400 250 170 150
Proposer’s Guide A9.3

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Problematic setups insensitivity estimation• The followings are extreme examples ofproblematic setups but are frequently
detected. Again, if they are not justified
clearly, it may lead to a rejection.
• “bandwidth used for sensitivity” is wider thantarget line width• “bandwidth used for sensitivity” is given in“aggregate bandwidth” even though the SG istargeting spectral observation10

Imaging & Correlator• Imaging– angular resolution (AR) and largest angular scale(LAS) needed to image complex emission should
be carefully justified– PIs should also pay attention to the expected
image dynamic range (see PG A.9.1)• Correlator configuration– correlator setup and the placement of spectral
windows should be justified (enough resolution?)– check whether any of the spectral windows areseverely impacted by atmospheric absorption
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Needs Specific Justification• Any of the followings trigger an additional text
box (“Choices to be justified”) at the bottom ofTJ section, and the PI is requested to justify it
explicitly• Override of OT’s sensitivity-based time estimate• Time Constraint observations• User-defined calibration• Low maximum source elevation (Dec.>37deg)• Single polarization• Non-Nyquist Mosaic Sampling

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Tips
• polarization observation toward highdeclination (far-north) source is unfeasible– more than three hours continuous observation isnot feasible• use appropriate unit at “Desired sensitivity perpointing”, otherwise the input value maysuffer rounding issue
e.g. (bad) 0.000007 Jy → (good) 7 uJy(microJy)
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Take-Home Massage• double-check values you input!
• refer the documents and Knowledgebase
articles• if you have any question, please do nothesitate to consult with EA-ARC via Helpdesk

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