Pith. sign in

REVIEW 4 major objections 5 minor 1 cited by

Detectability of the 21 cm signal with BINGO through cross-correlation with photometric surveys

T0 review · 4 major / 5 minor · reviewed 2026-08-15 · deepseek-v4-flash

Pith's one-line read The 21 cm signal from BINGO remains detectable when cross-correlated with LSST photometric galaxies, despite photo-z uncertainties that reduce its significance to the level of the autocorrelation.

desk verdict A solid, clearly-written simulation forecast of BINGO x LSST cross-correlation; the relative photo-z effect is convincing, but the absolute detectability numbers rest on a covariance the authors admit is not representative. read the letter →

arxiv 2506.19068 v1 pith:7UTDZXTP submitted 2025-06-23 astro-ph.CO

classification astro-ph.CO
keywords 21cmintensitymappingBINGOLSSTcross-correlationangularpowerspectrumphotometricredshiftGNILCforegroundcleaningneutralhydrogen
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper tries to establish that the 21 cm neutral-hydrogen signal observed by the BINGO radio telescope can be detected through cross-correlation with photometric galaxies from the LSST survey, despite the blurring introduced by photometric redshift errors. Using lognormal sky simulations over BINGO's frequency range, with thermal noise, foregrounds, and a needlet-based cleaning step, the authors show that photo-z uncertainty degrades the cross-correlation significance down to about the level of the autocorrelation detection, but does not erase it. The detection survives across the full redshift range where the surveys overlap, centered near mean redshifts 0.25, 0.35, and 0.45. A sympathetic reader would care because most previous 21 cm cross-correlations have relied on spectroscopic galaxy surveys; showing that a photometric survey works would widen the pool of usable data for intensity mapping.

What carries the argument

The argument rests on three pieces: lognormal realizations of the cosmological HI and galaxy fields generated from theoretical angular power spectra; a foreground-cleaning pipeline, Generalized Needlet Internal Linear Combination, a component-separation method that exploits the smooth frequency structure of foregrounds, followed by debiasing of the power spectra; and the measured angular power spectrum, estimated through pseudo-$C_\ell$ mode coupling in the multipole range $99<\ell<309$. The decisive choice is to cross-correlate each narrow HI bin with the entire photometric bin rather than selecting galaxies that match the HI bin width. That choice preserves the cross-correlation amplitude while producing a wider scatter, and the null test with Gaussian random maps attributes the scatter to photo-z scatter.

What would settle it

Take the 50 cleaned realizations, estimate the covariance directly from their measured power spectra (or generate enough cleaned maps to do so), and recompute $\sqrt{\Delta\chi^2}$ in the same multipole range; if the significance drops below the detection threshold, the detectability claim fails. Alternatively, apply the same pipeline to real BINGO and LSST data and check whether the measured cross-power spectrum amplitude is consistent with the model at the claimed significance.

Watch

Extended reading notes

Core claim

The central claim is that the HI signal remains detectable through the angular power spectrum cross-correlation between foreground-cleaned BINGO-like maps and LSST-like photometric galaxy bins, even when photometric redshift errors are as large as LSST's. The photo-z errors do not bias the average cross-correlation amplitude; they add a noise-like contribution from galaxies that do not physically overlap the narrow HI redshift bin, enlarging the error bars until the statistical significance is comparable to the autocorrelation. For the HI bins closest to the center of each photometric bin, the significance is sufficient to claim detection, and the cross-correlation amplitude constrains the degenerate product $b_{\rm HI}\Omega_{\rm HI} r$ without the bias that appears in the autocorrelation at higher redshifts.

Load-bearing premise

The detection significance is computed with a covariance matrix built from fast simulations that add noise and foreground residuals to the HI signal, not from the actual cleaned maps; the paper itself notes these fast simulations are not representative of the cleaned maps, so the reported significances may be biased.

Editorial extensions

If this is right

  • If the paper is right, BINGO and LSST data can jointly detect the 21 cm signal in cross-correlation with significance comparable to BINGO's autocorrelation for the three central redshift bins.
  • The full photometric bin preserves the cross-correlation amplitude, so photometric surveys need not be sliced into narrow redshift bins to be useful for intensity mapping.
  • The cross-correlation provides an unbiased constraint on the product $b_{\rm HI}\Omega_{\rm HI} r$, with a 1$\sigma$ uncertainty around 20% of the theoretical value at the central bins, whereas the autocorrelation estimate drifts at higher redshift.
  • Galaxies in the photometric bin that do not overlap the HI bin act like extra noise, so their contribution explains why cross- and auto-correlation end up with similar detection significance.
  • Because contaminating signals in the two datasets are uncorrelated, the cross-correlation keeps a nearly scale-independent contamination factor even where the autocorrelation is badly affected at $\ell\gtrsim300$.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • A testable extension would be to recompute the detection significance using a covariance estimated directly from the cleaned maps rather than from the fast simulations; if the fast-simulation covariance is optimistic, the reported significance could shrink.
  • The same pipeline should transfer to other photometric surveys with narrower photo-z errors, and if photo-z scatter is the dominant noise term, narrower photo-z should directly raise the significance.
  • Co-adding the 30 BINGO bins within each photo-z bin might increase the signal-to-noise ratio beyond the per-bin analysis, an avenue the paper mentions as future work.
  • The null test suggests a practical diagnostic for real data: cross-correlating a cleaned HI map with a shuffled galaxy catalog should reproduce the noise-like error inflation seen in the simulations.
Share X Bluesky LinkedIn Reddit HN

Signed reviews

No signed human review yet.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

4 major / 5 minor

Summary. The manuscript uses lognormal FLASK simulations to assess whether the BINGO 21 cm intensity mapping survey can detect the HI signal by cross-correlating with LSST photometric galaxy catalogs. The authors generate 30 BINGO frequency bins with thermal noise and foregrounds, apply GNILC foreground cleaning with debiasing to 50 realizations, and build LSST-like galaxy maps in three photo-z bins with realistic number densities and photo-z errors. They measure auto- and cross-angular power spectra, compute detection significance via sqrt(Delta chi^2), and fit the degenerate amplitude b_HI Omega_HI r. The main claim is that photo-z errors add noise that reduces the cross-correlation significance to levels comparable to the autocorrelation, but the signal remains detectable, and the degenerate astrophysical parameters can be constrained.

Significance. If the central claim holds, this is a useful feasibility study for a relatively unexplored observational route: using photometric galaxy surveys, rather than spectroscopic ones, for HI intensity mapping cross-correlations. The paper has clear strengths: it builds a reasonably detailed end-to-end simulation pipeline including realistic foregrounds, GNILC cleaning, debiasing, a null test, and parameter estimation; it uses public tools (FLASK, UCLC_l, NaMaster); and it makes an explicit comparison with a previous spectroscopic-based study. The novelty of using the full photo-z bin, rather than slicing to match the HI bin width, is a genuine contribution. However, the quantitative detectability claim rests on a significance calculation whose covariance is taken from 'fast' simulations that the authors themselves state are not representative of the cleaned maps, and the injection and detection template share the same theoretical power spectrum. Both issues need to be addressed before the abstract's 'remains detectable' statement is fully supported.

major comments (4)
  1. [Sec. 4.2.2, Fig. 8] The sqrt(Delta chi^2) values for the GNILC-deb scenario are computed using the covariance matrix from the 1500 fast simulations (HI+WN+Fg), not from the GNILC-cleaned maps. The fast simulations omit the cleaning-induced signal loss and the non-white noise structure produced by GNILC, and the authors themselves note that the green and purple points diverge in Fig. 8, concluding that the fast simulations 'are not representative enough of the foreground cleaned maps.' Since the abstract's detectability claim is an absolute statement built on these significance values, the covariance mismatch must be quantified. I recommend comparing the fast-simulation covariance with one estimated from cleaned maps (or from an analytic model of the cleaning-induced noise), and showing how the reported significance values and their error bars change. Without this, the central claim is not fully supported.
  2. [Secs. 2 and 3; Eq. (2.7)] The simulated HI and galaxy maps are generated with FLASK using the UCLC_l angular power spectra, and the detection template used in the chi^2 statistic of Sec. 4.2.2 is the same UCLC_l model. The analysis is therefore a closed-loop recovery of an injected signal from a known model: any error or bias in the theoretical power spectrum is common to both simulation and template and cannot be detected. This inflates the significance relative to what would be obtained if the true sky differed from the model. I suggest testing robustness by injecting the signal with an alternate power spectrum (e.g., a different set of astrophysical parameters or a different nonlinear prescription) while keeping the detection template fixed, and reporting the resulting significance. This would turn the circularity concern into a quantitative statement.
  3. [Sec. 4.2.2] The multipole range 99 < ell < 309 used for the significance calculation is described as chosen to 'avoid multipole with poor SNR and to maximize the statistical significance.' Selecting the analysis range after inspecting the results, without a penalty or a pre-specified criterion, introduces an a posteriori selection that can bias the reported significance upward. The authors should either fix the range before the analysis, show the significance for a set of pre-defined ranges, or correct for the number of trial ranges considered. This is especially important because the same range is used for the parameter constraints in Sec. 5.
  4. [Secs. 4.2.1 and 5; Figs. 5 and 9] The null test uses Gaussian random maps with standard deviation sigma to mimic non-correlated galaxies, but such maps have white-noise statistics rather than a realistic galaxy field with clustering and shot noise. The test therefore demonstrates only that adding an uncorrelated random field increases the variance of the cross-spectrum, not specifically that photometric redshift uncertainty has that effect. The interpretation that photo-z errors are the cause of the enlarged 68% regions should be supported by comparing against simulations where the photo-z scatter is realized in the galaxy positions, or by using a galaxy mock with an explicit photo-z error model. Additionally, the parameter constraints in Sec. 5 inherit the covariance-mismatch issue noted above, so the reported 1-sigma dispersions on b_HI Omega_HI and b_HI Omega_HI r may be underestimated until the covariance is validated.
minor comments (5)
  1. [Sec. 4.2.2] The text reads 'the three three scenarios'; this should be 'the three scenarios.'
  2. [Sec. 5, Fig. 9 caption] The caption refers to 'scenarios (i) to (vi)' but the text in Sec. 4.2.1 defines only scenarios (i) through (iv). Please make the numbering consistent.
  3. [Throughout] There are several typographical issues, including missing spaces ('Hisignal'), 'thje' instead of 'the', and 'scenarions' instead of 'scenarios.' A careful proofreading pass is recommended.
  4. [Sec. 2.1, Eq. (2.6)] The notation phi'(z) is used for both the galaxy selection function n(z) and the HI projection kernel, but the prime is not defined explicitly; please define it at first use to avoid confusion.
  5. [Sec. 4.1] The description of the fast simulations states that the foreground residual is repeated every 50 realizations. This introduces correlations among realizations that should be acknowledged when using these simulations for the covariance matrix, since the effective number of independent realizations is smaller than 1500.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the detectability forecast is a self-contained Monte Carlo study conditional on stated model assumptions.

full rationale

The paper's derivation chain is a standard simulation forecast: choose a fiducial cosmology and HI bias/abundance values, compute theoretical angular power spectra with UCLC_l, generate lognormal realizations with FLASK using those spectra, add instrument noise and foregrounds, apply GNILC cleaning with debiasing transfer functions, estimate pseudo-C_ell, and finally quantify detectability with a chi^2 statistic against the same theoretical model. The fact that the injected signal and the detection template share the same UCLC_l model does not make the result circular: the reported significance values are not assumed but are computed from the scatter of 50 cleaned realizations and a 1500-realization covariance, and they depend nontrivially on thermal noise, photo-z smearing, foreground residuals, and cleaning-induced signal loss. The debiasing factors S_i(ell) and S_{i,j}(ell) are calibration transfer functions derived from simulated signal realizations, not fitted parameters renamed as predictions. The parameter-estimation section is a recovery test against known input amplitudes, explicitly benchmarking fitted b_HI Omega_HI and b_HI Omega_HI r against their theoretical values, so it is not an empirical prediction derived from itself. The paper's own caveat that the fast simulations are not fully representative of the GNILC-deb maps is a statistical validity concern about the covariance matrix, not a circular step: it does not reduce the detectability claim to its own inputs by construction. No load-bearing self-citation or imported uniqueness theorem appears; the GNILC method is cited from the external literature [71,15], and the BINGO companion papers are used for simulation methodology rather than to justify the central result. The central claim is therefore a conditional feasibility forecast with clearly stated assumptions, and no circular reduction is exhibited.

Assumptions & free parameters 1 free parameters · 7 assumptions · 0 invented entities

The central claim rests on a closed-loop simulation assumption, adopted external inputs (WMAP5 cosmology, LSST DESC selection function, Zhang et al. HI parameters), and the scale-independent r assumption. There are no invented physical entities. One analysis choice, the multipole range, acts as a free parameter that affects the reported detection significance.

free parameters (1)
  • Multipole range for detection significance = 99 < ell < 309
    Selected post hoc in Sec. 4.2.2 to avoid low-SNR multipoles and maximize statistical significance; the reported sqrt(delta chi^2) values depend on this choice.
assumptions (7)
  • domain assumption Lognormal fields from FLASK faithfully reproduce the clustering and covariance of 21 cm and galaxy density fields.
    All simulated maps in Sec. 3 are generated with FLASK assuming lognormal statistics; deviations from lognormality or non-Gaussian covariance would change the significance estimates.
  • domain assumption The theoretical angular power spectrum from UCLC_l with CLASS matter power spectrum is the correct model for both the injected signal and the detection template.
    Sec. 2.1 defines the model, Sec. 3 uses it as FLASK input, and Sec. 4.2.2 uses it in the chi^2 statistic; this closed loop excludes model misspecification.
  • domain assumption The WMAP5 fiducial cosmology (Omega_m=0.26, Omega_b=0.044, Omega_Lambda=0.74, H0=71) is adopted.
    Sec. 3 follows companion papers; a different cosmology would change the matter power spectrum and the expected APS amplitudes.
  • domain assumption The HI bias and Omega_HI values in each redshift bin, taken from Zhang et al. (2022), are correct.
    Sec. 3.1.1 uses values decreasing with redshift; these set the injected signal amplitude and therefore directly set the detectability forecast.
  • domain assumption The LSST radial selection function (z0=0.24, beta=0.90) and sigma_z=0.03(1+z) represent the expected 10-year LSST performance.
    Sec. 3.2 adopts these from the LSST DESC; they control the photo-z smearing, which is the main noise source studied in the paper.
  • domain assumption The cross-correlation coefficient r is scale-independent over the multipole range used for parameter estimation.
    Sec. 5 assumes r_ell = r because it approaches unity on large scales; the assumption is stated and reasonable, but not validated within the simulations.
  • domain assumption The thermal noise is white and uncorrelated with galaxy maps.
    Sec. 4.1 sets the additive debiasing term to zero for cross-correlation; 1/f noise and polarization leakage are not modeled, as acknowledged in Sec. 4.2.2 and Sec. 6.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Detectability of the 21 cm signal with BINGO through cross-correlation with photometric surveys." pith.science (2026). https://pith.science/paper/7UTDZXTP

@misc{pith2026250619068,
  author       = {Pith},
  title        = {Pith review of: Detectability of the 21 cm signal with BINGO through cross-correlation with photometric surveys},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/7UTDZXTP}},
  note         = {Machine review of arXiv:2506.19068}
}
read the original abstract

21 cm intensity mapping (HI IM) can efficiently map large cosmic volumes with good redshift resolution, but systematics and foreground contamination pose major challenges for extracting accurate cosmological information. Cross-correlation with galaxy surveys offers an efficient mitigation strategy, as both datasets have largely uncorrelated systematics. We evaluate the detectability of the 21 cm signal from the BINGO radio telescope by cross-correlating with the LSST photometric survey, given their strong overlap in area and redshift. Using lognormal simulations, we model the cosmological signal in the BINGO frequency range (980 - 1260 MHz), incorporating thermal noise, foregrounds, and cleanup. The LSST simulations include uncertainties in photometric redshift (photo-z) and galaxy number density in the first three redshift intervals (mean redshift approximately equal to 0.25, 0.35, 0.45), corresponding to the expected performance after 10 years of the survey. We show that photo-z errors significantly increase the noise in the cross-correlation, reducing its statistical significance to levels comparable to those of the autocorrelation. Still, the HI signal remains detectable through the cross-correlation, even with photo-z uncertainties similar to those of the LSST. Our results corroborate the feasibility of this approach under realistic conditions and motivate further refinement of the current analysis methods.

Discussion (0). Continue with ORCID to comment.

Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. Unveiling dark energy properties with high-sensitivity cross-correlations of neutral hydrogen intensity mapping and galaxy surveys

    astro-ph.CO 2026-07 conditional novelty 6.0 of 10

    In simulations, foreground-cleaned 21 cm hydrogen–galaxy cross-power spectra recover the dynamical dark energy parameters (w0, wa) without bias when galaxy redshift bins are narrow.

Reference graph

Works this paper leans on

83 extracted references · 70 canonical work pages · cited by 1 Pith paper

  1. [1]

    Robertson,Galaxy Formation and Reionization: Key Unknowns and Expected Breakthroughs by the James Webb Space Telescope,Ann

    B.E. Robertson,Galaxy Formation and Reionization: Key Unknowns and Expected Breakthroughs by the James Webb Space Telescope,Ann. Rev. Astron. Astrophys.60(2022) 121 [2110.13160]

  2. [2]

    Amendola, S

    L. Amendola, S. Appleby, A. Avgoustidis, D. Bacon, T. Baker, M. Baldi et al.,Cosmology and fundamental physics with the Euclid satellite,Living rev. relativ.21(2018) 1

  3. [3]

    Ivezi ´c, S.M

    Ž. Ivezi ´c, S.M. Kahn, J.A. Tyson, B. Abel, E. Acosta, R. Allsman et al.,LSST: from science drivers to reference design and anticipated data products,The Astrophysical Journal873(2019) 111

  4. [4]

    Chen,The tianlai project: a 21cm cosmology experiment, inInt

    X. Chen,The tianlai project: a 21cm cosmology experiment, inInt. J. Mod. Phys. Conf. Ser., vol. 12, pp. 256–263, World Scientific, 2012. – 20 –

  5. [5]

    Crichton, M

    D. Crichton, M. Aich, A. Amara, K. Bandura, B.A. Bassett, C. Bengaly et al.,Hydrogen intensity and real-time analysis experiment: 256-element array status and overview,J. Astron. Telesc. Instrum. Syst. 8(2022) 011019

  6. [6]

    R. Nan, D. Li, C. Jin, Q. Wang, L. Zhu, W. Zhu et al.,The five-hundred-meter aperture spherical radio telescope (FAST) project,Int. J. Mod. Phys. D20(2011) 989

  7. [7]

    Bacon, R.A

    D.J. Bacon, R.A. Battye, P. Bull, S. Camera, P.G. Ferreira, I. Harrison et al.,Cosmology with phase 1 of the square kilometre array red book 2018: technical specifications and performance forecasts, Publications of the Astronomical Society of Australia37(2020) e007

  8. [8]

    Battye, I

    R. Battye, I. Browne, C. Dickinson, G. Heron, B. Maffei and A. Pourtsidou,HI intensity mapping: a single dish approach,Mon. Not. R. Astron. Soc.434(2013) 1239

Show all 83 references
  1. [9]

    Bigot-Sazy, C

    M.-A. Bigot-Sazy, C. Dickinson, R.A. Battye, I. Browne, Y .-Z. Ma, B. Maffei et al.,Simulations for single-dish intensity mapping experiments,Mon. Not. R. Astron. Soc.454(2015) 3240

  2. [10]

    Abdalla, E.G

    E. Abdalla, E.G. Ferreira, R.G. Landim, A.A. Costa, K.S. Fornazier, F.B. Abdalla et al.,The BINGO project-I. baryon acoustic oscillations from integrated neutral gas observations,Astron. Astrophys.664 (2022) A14

  3. [11]

    Santos, M

    M.G. Santos, M. Cluver, M. Hilton, M. Jarvis, G.I. Jozsa, L. Leeuw et al.,Meerklass: Meerkat large area synoptic survey,arXiv preprint arXiv:1709.06099(2017)

  4. [12]

    Bandura, G.E

    K. Bandura, G.E. Addison, M. Amiri, J.R. Bond, D. Campbell-Wilson, L. Connor et al.,Canadian hydrogen intensity mapping experiment (chime) pathfinder, inGround-based and Airborne Telescopes V, vol. 9145, p. 914522, SPIE, 2014

  5. [13]

    Tegmark, A

    M. Tegmark, A. de Oliveira-Costa and A.J.S. Hamilton,High resolution foreground cleaned cmb map from wmap,Phys. Rev. D68(2003) 123523

  6. [14]

    Alonso, P

    D. Alonso, P. Bull, P.G. Ferreira and M.G. Santos,Blind foreground subtraction for intensity mapping experiments,Mon. Not. R. Astron. Soc.447(2015) 400

  7. [15]

    Olivari, M

    L. Olivari, M. Remazeilles and C. Dickinson,Extracting Hicosmological signal with generalized needlet internal linear combination,Mon. Not. R. Astron. Soc.456(2016) 2749

  8. [16]

    Carucci, M.O

    I.P. Carucci, M.O. Irfan and J. Bobin,Recovery of 21-cm intensity maps with sparse component separation,Mon. Not. R. Astron. Soc.499(2020) 304

  9. [17]

    Wuensche, T

    C.A. Wuensche, T. Villela, E. Abdalla, V . Liccardo, F. Vieira, I. Browne et al.,The BINGO project-II. instrument description,Astron. Astrophys.664(2022) A15

  10. [18]

    Harper, C

    S. Harper, C. Dickinson, R. Battye, S. Roychowdhury, I. Browne, Y .-Z. Ma et al.,Impact of simulated 1/f noise for hi intensity mapping experiments,Mon. Not. R. Astron. Soc.478(2018) 2416

  11. [19]

    Y . Li, M.G. Santos, K. Grainge, S. Harper and J. Wang,H i intensity mapping with meerkat: 1/f noise analysis,Mon. Not. R. Astron. Soc.501(2021) 4344

  12. [20]

    J. Ding, X. Wang, U.-L. Pen and X.-D. Li,Correlation-based beam calibration of 21 cm intensity mapping,Astrophys. J. Supp.274(2024) 44

  13. [21]

    Wang, M.G

    J. Wang, M.G. Santos, P. Bull, K. Grainge, S. Cunnington, J. Fonseca et al.,Hi intensity mapping with MeerKAT: calibration pipeline for multidish autocorrelation observations,Mon. Not. R. Astron. Soc. 505(2021) 3698

  14. [22]

    Chang, U.-L

    T.-C. Chang, U.-L. Pen, K. Bandura and J.B. Peterson,An intensity map of hydrogen 21-cm emission at redshift z∼0.8,Nature466(2010) 463

  15. [23]

    Switzer, K

    E. Switzer, K. Masui, K. Bandura, L.-M. Calin, T.-C. Chang, X.-L. Chen et al.,Determination of z∼0.8 neutral hydrogen fluctuations using the 21 cm intensity mapping autocorrelation,Mon. Not. R. Astron. Soc.434(2013) L46

  16. [24]

    Masui, E

    K. Masui, E. Switzer, N. Banavar, K. Bandura, C. Blake, L.-M. Calin et al.,Measurement of 21 cm brightness fluctuations at z∼0.8in cross-correlation,Astrophys. J.763(2013) L20. – 21 –

  17. [25]

    L. Wolz, A. Pourtsidou, K.W. Masui, T.-C. Chang, J.E. Bautista, E.-M. Müller et al.,Hi constraints from the cross-correlation of eBOSS galaxies and Green Bank Telescope intensity maps,Mon. Not. R. Astron. Soc.510(2021) 3495

  18. [26]

    Cunnington, Y

    S. Cunnington, Y . Li, M.G. Santos, J. Wang, I.P. Carucci, M.O. Irfan et al.,HI intensity mapping with meerkat: power spectrum detection in cross-correlation with wigglez galaxies,Mon. Not. R. Astron. Soc.518(2023) 6262

  19. [27]

    Amiri, K

    M. Amiri, K. Bandura, T. Chen, M. Deng, M. Dobbs, M. Fandino et al.,Detection of cosmological 21 cm emission with the canadian hydrogen intensity mapping experiment,Astrophys. J.947(2023) 16

  20. [28]

    Paul, M.G

    S. Paul, M.G. Santos, Z. Chen and L. Wolz,A first detection of neutral hydrogen intensity mapping on mpc scales at z≈0.32and z≈0.44,arXiv preprint arXiv:2301.11943(2023)

  21. [29]

    Dodelson,Modern cosmology, Academic Press, Massachusetts, USA (2003)

    S. Dodelson,Modern cosmology, Academic Press, Massachusetts, USA (2003)

  22. [30]

    Z. Gao, A. Raccanelli and Z. Vlah,Asymptotic connection between full-and flat-sky angular correlators, Phys. Rev. D108(2023) 043503

  23. [31]

    Carucci, J.L

    I.P. Carucci, J.L. Bernal, S. Cunnington, M.G. Santos, J. Wang, J. Fonseca et al.,Hydrogen intensity mapping with meerkat: Preserving cosmological signal by optimising contaminant separation,arXiv preprint arXiv:2412.06750(2024)

  24. [32]

    Blake,Power spectrum modelling of galaxy and radio intensity maps including observational effects, Mon

    C. Blake,Power spectrum modelling of galaxy and radio intensity maps including observational effects, Mon. Not. R. Astron. Soc.489(2019) 153

  25. [33]

    Cunnington and L

    S. Cunnington and L. Wolz,Accurate fourier-space statistics for line intensity mapping: Cartesian grid sampling without aliased power,Mon. Not. R. Astron. Soc.528(2024) 5586

  26. [34]

    Benabou, I

    J.N. Benabou, I. Sands, H.S.G. Gebhardt, C. Heinrich and O. Doré,Wide-angle effects in the power spectrum multipoles in next-generation redshift surveys,Phys. Rev. D110(2024) 083526

  27. [35]

    Pourtsidou, D

    A. Pourtsidou, D. Bacon and R. Crittenden,Cross-correlation cosmography with intensity mapping of the neutral hydrogen 21 cm emission,Phys. Rev. D92(2015) 103506

  28. [36]

    Padmanabhan, A

    H. Padmanabhan, A. Refregier and A. Amara,Impact of astrophysics on cosmology forecasts for 21 cm surveys,Mon. Not. R. Astron. Soc.485(2019) 4060

  29. [37]

    Padmanabhan, A

    H. Padmanabhan, A. Refregier and A. Amara,Cross-correlating 21 cm and galaxy surveys: implications for cosmology and astrophysics,Mon. Not. R. Astron. Soc.495(2020) 3935

  30. [38]

    Shi, Y .-S

    F. Shi, Y .-S. Song, J. Asorey, D. Parkinson, K. Ahn, J. Yao et al.,Hir4: cosmological signatures imprinted on the cross-correlation between a 21-cm map and galaxy clustering,Mon. Not. R. Astron. Soc.499(2020) 4613

  31. [39]

    Cunnington, L

    S. Cunnington, L. Wolz, A. Pourtsidou and D. Bacon,Impact of foregrounds on HI intensity mapping cross-correlations with optical surveys,Mon. Not. R. Astron. Soc.488(2019) 5452

  32. [40]

    Abbott, F

    T. Abbott, F. Abdalla, A. Alarcon, S. Allam, F. Andrade-Oliveira, J. Annis et al.,Dark energy survey year 1 results: Measurement of the baryon acoustic oscillation scale in the distribution of galaxies to redshift 1,Mon. Not. R. Astron. Soc.483(2019) 4866

  33. [41]

    Benitez, R

    N. Benitez, R. Dupke, M. Moles, L. Sodre, J. Cenarro, A. Marin-Franch et al.,J-pas: the javalambre-physics of the accelerated universe astrophysical survey,arXiv preprint arXiv:1403.5237 (2014)

  34. [42]

    Hikage, M

    C. Hikage, M. Oguri, T. Hamana, S. More, R. Mandelbaum, M. Takada et al.,Cosmology from cosmic shear power spectra with subaru hyper suprime-cam first-year data,Publ. of the Astr. Soc. Japan71 (2019) 43

  35. [43]

    Serrano, E

    S. Serrano, E. Gaztañaga, F.J. Castander, M. Eriksen, R. Casas, D. Navarro-Gironés et al.,The physics of the accelerating universe survey: narrow-band image photometry,Monthly Notices of the Royal Astronomical Society523(2023) 3287. – 22 –

  36. [44]

    Loureiro, B

    A. Loureiro, B. Moraes, F.B. Abdalla, A. Cuceu, M. McLeod, L. Whiteway et al.,Cosmological measurements from angular power spectra analysis of boss dr12 tomography,Mon. Not. R. Astron. Soc. 485(2019) 326

  37. [45]

    L. Wolz, C. Tonini, C. Blake and J. Wyithe,Intensity mapping cross-correlations: connecting the largest scales to galaxy evolution,Mon. Not. R. Astron. Soc.458(2016) 3399

  38. [46]

    Sobreira, F

    F. Sobreira, F. de Simoni, R. Rosenfeld, L. da Costa, M. Maia and M. Makler,Cosmological forecasts from photometric measurements of the angular correlation function,Phys. Rev. D84(2011) 103001

  39. [47]

    McLeod, S.T

    M. McLeod, S.T. Balan and F.B. Abdalla,A joint analysis for cosmology and photometric redshift calibration using cross-correlations,Mon. Not. R. Astron. Soc.466(2017) 3558

  40. [48]

    Lesgourgues,The cosmic linear anisotropy solving system (class) i: Overview,arXiv preprint arXiv:1104.2932(2011)

    J. Lesgourgues,The cosmic linear anisotropy solving system (class) i: Overview,arXiv preprint arXiv:1104.2932(2011)

  41. [49]

    D. Blas, J. Lesgourgues and T. Tram,The cosmic linear anisotropy solving system (CLASS). Part II: approximation schemes,J. Cosmol. Astropart. Phys.2011(2011) 034

  42. [50]

    Alonso, J

    D. Alonso, J. Sanchez, A. Slosar and L.D.E.S. Collaboration,A unified pseudo-Cl framework,Mon. Not. R. Astron. Soc.484(2019) 4127

  43. [51]

    Hivon, K.M

    E. Hivon, K.M. Górski, C.B. Netterfield, B.P. Crill, S. Prunet and F. Hansen,Master of the cosmic microwave background anisotropy power spectrum: a fast method for statistical analysis of large and complex cosmic microwave background data sets,Astrophys. J.567(2002) 2

  44. [52]

    Mericia, L.C

    E.J. Mericia, L.C. Santos, C.A. Wuensche, V . Liccardo, C.P. Novaes, J. Delabrouille et al.,Testing synchrotron models and frequency resolution in bingo 21 cm simulated maps using gnilc,Astron. Astrophys.671(2023) A58

  45. [53]

    Novaes, J

    C.P. Novaes, J. Zhang, E.J. de Mericia, F.B. Abdalla, V . Liccardo, C.A. Wuensche et al.,The BINGO project-VIII. recovering the BAO signal in hi intensity mapping simulations,Astronomy&Astrophysics 666(2022) A83

  46. [54]

    Novaes, E.J

    C.P. Novaes, E.J. de Mericia, F.B. Abdalla, C.A. Wuensche, L. Santos, J. Delabrouille et al., Cosmological constraints from low redshift 21 cm intensity mapping with machine learning,Monthly Notices of the Royal Astronomical Society528(2024) 2078

  47. [55]

    Zhang, C

    Z. Zhang, C. Chang, P. Larsen, L.F. Secco, J. Zuntz and L.D.E.S. Collaboration,Transitioning from stage-iii to stage-iv: cosmology from galaxy×cmb lensing and shear×cmb lensing,Mon. Not. R. Astron. Soc.514(2022) 2181

  48. [56]

    Mandelbaum, T

    The LSST Dark Energy Science Collaboration, R. Mandelbaum, T. Eifler, R. Hložek, T. Collett, E. Gawiser et al.,The lsst dark energy science collaboration (desc) science requirements document, 2021

  49. [57]

    Shaw and M.A

    R.A. Shaw and M.A. Strauss,LSST data challenge handbook - version 1, 2011

  50. [58]

    Gorski, E

    K.M. Gorski, E. Hivon, A.J. Banday, B.D. Wandelt, F.K. Hansen, M. Reinecke et al.,Healpix: A framework for high-resolution discretization and fast analysis of data distributed on the sphere, Astrophys. J.622(2005) 759

  51. [59]

    Xavier, F.B

    H.S. Xavier, F.B. Abdalla and B. Joachimi,Improving lognormal models for cosmological fields,Mon. Not. R. Astron. Soc.459(2016) 3693 [1602.08503]

  52. [60]

    Zhang, P

    J. Zhang, P. Motta, C.P. Novaes, F.B. Abdalla, A.A. Costa, B. Wang et al.,The BINGO project-VI. Hi halo occupation distribution and mock building,Astron. Astrophys.664(2022) A19

  53. [61]

    Dunkley, E

    J. Dunkley, E. Komatsu, M. Nolta, D. Spergel, D. Larson, G. Hinshaw et al.,Five-year wilkinson microwave anisotropy probe* observations: likelihoods and parameters from the wmap data,Astrophys. J. Supp.180(2009) 306. – 23 –

  54. [62]

    Liccardo, E.J

    V . Liccardo, E.J. de Mericia, C.A. Wuensche, E. Abdalla, F.B. Abdalla, L. Barosi et al.,The BINGO project-IV. simulations for mission performance assessment and preliminary component separation steps,Astron. Astrophys.664(2022) A17

  55. [63]

    Fornazier, F.B

    K.S. Fornazier, F.B. Abdalla, M. Remazeilles, J. Vieira, A. Marins, E. Abdalla et al.,The bingo project-v. further steps in component separation and bispectrum analysis,Astron. Astrophys.664(2022) A18

  56. [64]

    Delabrouille, M

    J. Delabrouille, M. Betoule, J.-B. Melin, M.-A. Miville-Deschênes, J. Gonzalez-Nuevo, M. Le Jeune et al.,The pre-launch planck sky model: a model of sky emission at submillimetre to centimetre wavelengths,Astron. Astrophys.553(2013) A96

  57. [65]

    Remazeilles, C

    M. Remazeilles, C. Dickinson, A. Banday, M.-A. Bigot-Sazy and T. Ghosh,An improved source-subtracted and destriped 408-mhz all-sky map,Mon. Not. R. Astron. Soc.451(2015) 4311

  58. [66]

    Miville-Deschênes, N

    M.-A. Miville-Deschênes, N. Ysard, A. Lavabre, N. Ponthieu, J.-F. Macias-Perez, J. Aumont et al., Separation of anomalous and synchrotron emissions using wmap polarization data,Astron. Astrophys. 490(2008) 1093

  59. [67]

    Dickinson, R

    C. Dickinson, R. Davies and R. Davis,Towards a free–free template for cmb foregrounds,Mon. Not. R. Astron. Soc.341(2003) 369

  60. [68]

    Collaboration et al.,Planck 2015 results: Xxvi

    P. Collaboration et al.,Planck 2015 results: Xxvi. the second planck catalogue of compact sources, Astron. Astrophys.594(2016) A26

  61. [69]

    Tinker, B.E

    J.L. Tinker, B.E. Robertson, A.V . Kravtsov, A. Klypin, M.S. Warren, G. Yepes et al.,The large-scale bias of dark matter halos: numerical calibration and model tests,Astrophys. J.724(2010) 878

  62. [70]

    Abdalla, A

    F.B. Abdalla, A. Marins, P. Motta, E. Abdalla, R.M. Ribeiro, C.A. Wuensche et al.,The BINGO Project-III. optical design and optimization of the focal plane,Astron. Astrophys.664(2022) A16

  63. [71]

    Remazeilles, J

    M. Remazeilles, J. Delabrouille and J.-F. Cardoso,CMB and SZ effect separation with constrained Internal Linear Combinations,Mon. Not. R. Astron. Soc.410(2011) 2481 [1006.5599]

  64. [72]

    Cunnington, M.O

    S. Cunnington, M.O. Irfan, I.P. Carucci, A. Pourtsidou and J. Bobin,21-cm foregrounds and polarization leakage: cleaning and mitigation strategies,Mon. Not. R. Astron. Soc.504(2021) 208

  65. [73]

    L. Wolz, C. Blake and J. Wyithe,Determining the h i content of galaxies via intensity mapping cross-correlations,Mon. Not. R. Astron. Soc.470(2017) 3220

  66. [74]

    L. Wolz, S. Murray, C. Blake and J. Wyithe,Intensity mapping cross-correlations ii: Hi halo models including shot noise,Mon. Not. R. Astron. Soc.484(2019) 1007

  67. [75]

    Jiang, Y

    Y .-E. Jiang, Y . Gong, M. Zhang, Q. Xiong, X. Zhou, F. Deng et al.,Cross-correlation forecast of csst spectroscopic galaxy and meerkat neutral hydrogen intensity mapping surveys,Research in Astronomy and Astrophysics23(2023) 075003

  68. [76]

    Mazumder, L

    A. Mazumder, L. Wolz, Z. Chen, S. Paul, M. Santos, M. Jarvis et al.,HI intensity mapping with the MIGHTEE survey: First results of the HI power spectrum,arXiv preprint arXiv:2501.17564(2025)

  69. [77]

    Zheng, P

    J. Zheng, P. Tiwari, G.-B. Zhao, D.J. Schwarz, D. Bacon, S. Camera et al.,Cosmology from lofar two-metre sky survey data release 2: Cross-correlations with luminous red galaxies from eboss,arXiv preprint arXiv:2504.20722(2025)

  70. [78]

    Virtanen, R

    P. Virtanen, R. Gommers, T.E. Oliphant and et al.,Scipy 1.0: Fundamental algorithms for scientific computing in python,Nat. Methods17(2020) 261

  71. [79]

    Hartlap, P

    J. Hartlap, P. Simon and P. Schneider,Why your model parameter confidences might be too optimistic. unbiased estimation of the inverse covariance matrix,Astron. Astrophys.464(2007) 399

  72. [80]

    Price-Whelan, B

    A.M. Price-Whelan, B. Sip ˝ocz, H. Günther, P. Lim, S. Crawford, S. Conseil et al.,The astropy project: building an open-science project and status of the v2. 0 core package,Astron. J.156(2018) 123. – 24 –

  73. [81]

    Zonca, L

    A. Zonca, L. Singer, D. Lenz, M. Reinecke, C. Rosset, E. Hivon et al.,healpy: equal area pixelization and spherical harmonics transforms for data on the sphere in python,J. Open Source Softw.4(2019) 1298

  74. [82]

    Van Der Walt, S.C

    S. Van Der Walt, S.C. Colbert and G. Varoquaux,The numpy array: a structure for efficient numerical computation,Computing in science&engineering13(2011) 22

  75. [83]

    Hunter,Matplotlib: A 2d graphics environment,Comput

    J.D. Hunter,Matplotlib: A 2d graphics environment,Comput. Sci. Eng.9(2007) 90. – 25 –

Pith tools

Reviewed August 15, 2026 · model on record in the stance chip above.