RECORD
On the Uncertainties of Results Derived from HI Spectral Line Stacking Experiments
Astrophysics of Galaxies · Submitted 29 Apr 2019
abstract compiled · 2026-09-23 · no language-model review
The authors' main claim Our findings strongly suggest that any co-added HI galaxy spectrum needs to be fully modelled in the ways presented in this paper in order to apply accurate corrections for flux contamination and derive realistic uncertainties in total HI galaxy mass.
The compiled record
The paper's own sentences, arranged. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
Open the compiled record
The abstract, sentence by sentence
We present the results of a set of mock experiments aimed at quantifying the accuracy of results derived from HI spectral line stacking experiments. We focus on the effects of spatial and spectral aperture sizes and redshift uncertainties on co-added HI spectra, and by implication on the usefulness of results from HI line spectral stacking experiments. Using large spatial apertures to extract constituent galaxy spectra yields co-added spectra with high levels of contamination and with relatively low signal-to-noise ratios. These properties are also affected by the size of the spectral aperture as well as HI redshift uncertainties of galaxies. When redshift uncertainties are high, S/N decreases while the contamination level remains roughly constant. Using small spectral apertures in the presence of large HI redshift uncertainties can yield significant decreases in S/N without the expected decrease in amount of contaminant flux. Our simulations show that a co-added spectrum rarely yields an accurate measure of the total HI mass of a galaxy sample. Total mass is generally over/under-estimated for large/small spatial apertures, regardless of spectral aperture size. Our findings strongly suggest that any co-added HI galaxy spectrum needs to be fully modelled in the ways presented in this paper in order to apply accurate corrections for flux contamination and derive realistic uncertainties in total HI galaxy mass. Failing to do so will result in unreliable inferences of galaxy and cosmological parameters.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We present the results of a set of mock experiments aimed at quantifying the accuracy of results derived from HI spectral line stacking experiments. | contribution 1.00 | 0.94 | 0.04 | asserted 0.95 |
| s1 | We focus on the effects of spatial and spectral aperture sizes and redshift uncertainties on co-added HI spectra, and by implication on the usefulness of results from HI line spectral stacking experiments. | contribution 0.90 | 0.51 | 0.05 | asserted 0.78 |
| s2 | Using large spatial apertures to extract constituent galaxy spectra yields co-added spectra with high levels of contamination and with relatively low signal-to-noise ratios. | result 1.00 | 0.85 | 0.07 | asserted 1.00 |
| s3 | These properties are also affected by the size of the spectral aperture as well as HI redshift uncertainties of galaxies. | result 0.95 | 0.68 | 0.03 | asserted 1.00 |
| s4 | When redshift uncertainties are high, S/N decreases while the contamination level remains roughly constant. | result 1.00 | 0.85 | 0.05 | asserted 0.99 |
| s5 | Using small spectral apertures in the presence of large HI redshift uncertainties can yield significant decreases in S/N without the expected decrease in amount of contaminant flux. | result 1.00 | 0.86 | 0.07 | hedged possibility 0.97 |
| s6 | Our simulations show that a co-added spectrum rarely yields an accurate measure of the total HI mass of a galaxy sample. | result 1.00 | 0.94 | 0.29 | asserted 0.88 |
| s7 | Total mass is generally over/under-estimated for large/small spatial apertures, regardless of spectral aperture size. | result 1.00 | 0.90 | 0.14 | asserted 0.94 |
| s8 | Our findings strongly suggest that any co-added HI galaxy spectrum needs to be fully modelled in the ways presented in this paper in order to apply accurate corrections for flux contamination and derive realistic uncertainties in total HI galaxy mass. | interpretation 0.67 | 0.68 | 0.81 | hedged possibility 0.86 |
| s9 | Failing to do so will result in unreliable inferences of galaxy and cosmological parameters. | interpretation 0.93 | 0.25 | 0.15 | asserted 0.99 |
What was examined, and what was not
- arXiv listing abstract v1
- full text
- figures and tables
- references and citing sentences
- relations to other papers
- P abstract
- S sections
- T body sentences
- C citations
- R cross-paper relations
The paper
Original abstract
We present the results of a set of mock experiments aimed at quantifying the accuracy of results derived from HI spectral line stacking experiments. We focus on the effects of spatial and spectral aperture sizes and redshift uncertainties on co-added HI spectra, and by implication on the usefulness of results from HI line spectral stacking experiments. Using large spatial apertures to extract constituent galaxy spectra yields co-added spectra with high levels of contamination and with relatively low signal-to-noise ratios. These properties are also affected by the size of the spectral aperture as well as HI redshift uncertainties of galaxies. When redshift uncertainties are high, S/N decreases while the contamination level remains roughly constant. Using small spectral apertures in the presence of large HI redshift uncertainties can yield significant decreases in S/N without the expected decrease in amount of contaminant flux. Our simulations show that a co-added spectrum rarely yields an accurate measure of the total HI mass of a galaxy sample. Total mass is generally over/under-estimated for large/small spatial apertures, regardless of spectral aperture size. Our findings strongly suggest that any co-added HI galaxy spectrum needs to be fully modelled in the ways presented in this paper in order to apply accurate corrections for flux contamination and derive realistic uncertainties in total HI galaxy mass. Failing to do so will result in unreliable inferences of galaxy and cosmological parameters.
Human review
How the literature uses it
What this paper does with the arXiv papers it cites
What it cites · 1 sentence without a confident label
Uses the method or tool of 1 paper
-
To more closely mimic real data analysis procedures, rather than using the evaluated line width from the [ref] catalogue (which would not be available a priori for an observed galaxy), we use the evaluated absolute Vega $R$-band magnitude (corrected for intrinsic dust extinction) together with the Tully-Fisher relation [ref] from [ref] to calculate each galaxy's line width, corrected for the inclination of the disc.
100 deg$^2$ Mock Galaxy Cone for HI Surveys with the Early SKA · Spectral range · 0.95
Uses data or values from 1 paper
-
The cubes are based on the catalogue of evaluated galaxy properties from [ref] .
100 deg$^2$ Mock Galaxy Cone for HI Surveys with the Early SKA · Synthetic data cubes · 0.92
Discussion
Know something about this paper? Leave a comment, or highlight any passage above to comment on it.