IRAM Memo 2025-1 NOEMA sensitivity estimator

# IRAM Memo 2025-1
NOEMA sensitivity estimator

J. Pety, J. Boissier, S. Bardeau, E. Reynier
1. IRAM (Grenoble)
2. Observatoire de Paris

Date: Jul, 6 2026
Version 1.1

### Abstract:

This memo describes the equations used in the NOEMA sensitivity estimator available on the online sensitivity estimator (https://oms.iram.fr/tse/) and used for proposal submission in the Proposal Management System.

This memo is a full rewriting of the older memos dedicated to the subject to consolidate the equations and to take into account the new dual band and frequency cycling modes. The different versions of the memo 2015-2 are only kept in order to know how the sensitivity estimates were done in past proposal sessions.

- Contents
- NOEMA instrumental modes
- The interferometric point source sensitivity
  - Power and sensitivity measured at the correlator output for one baseline
  - Quantization efficiency
  - From the temperature power to the flux
  - Collecting the measurements from all baselines
  - Signal decorrelation
  - Noise vs signal
  - Summary and interpretation
- The interferometric extended source sensitivity
  - Yielding the interferometric extended source sensitivity
  - Interpretation
- The system temperature
  - Definition
  - Line vs continuum system temperature
  - Receiver temperature
- In practice
  - Line vs continuum system temperature
  - The number of polarizations
  - Actual computations
  - Elapsed telescope time vs on-source time
  - Sensitivity for a single-source, single-field observations
  - Sensitivity for track-sharing, single-field observations
  - Sensitivity for mosaicking
    - Area-based estimate for quick TSE calculations
    - Pointing-list estimate for PMS technical preparation
    - Bridge between the two estimates
- Acknowledgements
- References
- A few reminders: Flux vs brightness in radio-astronomy
  - Antenna power pattern, solid angles, associated efficiencies
  - Source and observed flux density
  - Observed brightnesses
  - Basic relation between received spectral power and sky brightness
  - Brightness temperature
    - Brightness temperature
    - Interpretation
  - Effective aperture and aperture efficiency
  - Relationship between effective aperture and antenna solid angle
    - Statement
    - Demonstration
    - Interpretation
- table revisions
  - Including the dichroic contribution (FEB-2025)
  - Revisions of and (JUL-2026)
- About this document ...