Boosting line intensity map signal-to-noise ratio with the Ly-α forest cross-correlation

Qezlou, Mahdi; Bird, Simeon; Lidz, Adam; Sun, Guochao; Newman, Andrew B; Rudie, Gwen C.; Ni, Yueying; Croft, Rupert A. C.; Matteo, Tiziana Di

doi:10.1093/mnras/stad1906

Cited by 3 publications

(2 citation statements)

References 84 publications

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“…Concurrently, Lyman-α tomography surveys with a high sightline density have allowed mapping coherent Mpc-scale overdensities [56,57,123,124]. The simulation suite is applicable to other cosmological probes, in particular the emerging field of line intensity mapping [125], and its cross-correlation with the Lyman-α forest [126]. In future work we will use the simulation suite and spectra presented here for comparisons to these other summary statistics.…”

Section: Discussionmentioning

confidence: 99%

PRIYA: a new suite of Lyman-α forest simulations for cosmology

Bird,

Fernandez,

et al. 2023

J. Cosmol. Astropart. Phys.

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We present the PRIYA suite of cosmological simulations, based on the code and hydrodynamic model of the ASTRID simulation, and designed for cosmological analyses of the Lyman-α forest. Our simulation suite spans a 9-dimensional parameter space, including 4 cosmological parameters and 5 astrophysical/thermal parameters. We have run 48 low fidelity simulations with 15363 particles in a 120 Mpc/h box and 3 high fidelity simulations with 30723 particles in a 120 Mpc/h box. All our simulations include a full physics model for galaxy formation, including supernova and AGN feedback, and thus also contain a realistic population of DLAs. We advance on earlier simulations suites by larger particle loads, by incorporating new physical models for patchy hydrogen and helium reionization, and by self-consistently incorporating a model for AGN feedback. We show that patchy helium reionization imprints an excess in the 1D flux power spectrum on large scales, which may allow future measurements of helium reionization bubble sizes. Simulation parameters are chosen based on a Latin hypercube design and a Gaussian process is used to interpolate to arbitrary parameter combinations. We build a multi-fidelity emulator for the 1D flux power spectrum and the mean IGM temperature. We show that our final interpolation error is < 1% and that our simulations produce a flux power spectrum converged at the percent level for z = 5.4–2.2. Our simulation suite will be used to interpret Lyman-α forest 1D flux power spectra from SDSS and future DESI data releases.

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Section: Discussionmentioning

confidence: 99%

PRIYA: a new suite of Lyman-α forest simulations for cosmology

Bird,

Fernandez,

et al. 2023

J. Cosmol. Astropart. Phys.

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“…Our construction of Lyα absorption spectra from the ASTRID simulations follows the procedures described in Section 2.2 of Qezlou et al (2022) and Section 3.1 of Qezlou et al (2023). Briefly, each gas particle in the simulation is treated as an individual absorber with internal physical properties smoothed by a quintic spline kernel.…”

Section: Lyα Optical Depthsmentioning

confidence: 99%

LATIS: Constraints on the Galaxy–Halo Connection at z ∼ 2.5 from Galaxy–Galaxy and Galaxy–Lyα Clustering

Newman,

Qezlou,

Chartab

et al. 2024

ApJ

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The connection between galaxies and dark matter halos is often quantified using the stellar mass–halo mass (SMHM) relation. Optical and near-infrared imaging surveys have led to a broadly consistent picture of the evolving SMHM relation based on measurements of galaxy abundances and angular correlation functions. Spectroscopic surveys at z ≳ 2 can also constrain the SMHM relation via the galaxy autocorrelation function and through the cross-correlation between galaxies and Lyα absorption measured in transverse sight lines; however, such studies are very few and have produced some unexpected or inconclusive results. We use ∼3000 spectra of z ∼ 2.5 galaxies from the Lyα Tomography IMACS Survey (LATIS) to measure the galaxy–galaxy and galaxy–Lyα correlation functions in four bins of stellar mass spanning 109.2 ≲ M */M ⊙ ≲ 1010.5. Parallel analyses of the MultiDark N-body and ASTRID hydrodynamic cosmological simulations allow us to model the correlation functions, estimate covariance matrices, and infer halo masses. We find that results of the two methods are mutually consistent and broadly accord with standard SMHM relations. This consistency demonstrates that we are able to measure and model Lyα transmission fluctuations δ F in LATIS accurately. We also show that the galaxy–Lyα cross-correlation, a free by-product of optical spectroscopic galaxy surveys at these redshifts, can constrain halo masses with similar precision to galaxy–galaxy clustering.

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Optimisation-based alignment of wide-band integrated superconducting spectrometers for submillimeter astronomy

Moerman,

Karatsu,

Yates

et al. 2024

A&A

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Integrated superconducting spectrometers (ISSs) for wide-band submillimeter (submm) astronomy use quasi-optical systems for coupling radiation from the telescope to the instrument. Misalignment in these systems is detrimental to the system performance. The common method of using an optical laser to align the quasi-optical components requires an accurate alignment of the laser to the submm beam from the instrument, which is not always guaranteed to a sufficient accuracy. We develop an alignment strategy for wide-band ISSs that directly uses the submm beam of the wide-band ISS. The strategy should be applicable in both telescope and laboratory environments. Moreover, the strategy should deliver similar quality of the alignment across the spectral range of the wide-band ISS. We measured the misalignment in a quasi-optical system operating at submm wavelengths using a novel phase and amplitude measurement scheme that is capable of simultaneously measuring the complex beam patterns of a direct-detecting ISS across a harmonic range of frequencies. The direct detection nature of the microwave kinetic inductance detectors in our device-under-test, DESHIMA 2.0, necessitates the use of this measurement scheme. Using geometrical optics, the measured misalignment, a mechanical hexapod, and an optimisation algorithm, we followed a numerical approach to optimise the positioning of corrective optics with respect to a given cost function. Laboratory measurements of the complex beam patterns were taken across a harmonic range between 205 and 391 GHz and were simulated through a model of the ASTE telescope in order to assess the performance of the optimisation at the ASTE telescope. Laboratory measurements show that the optimised optical setup corrects for tilts and offsets of the submm beam. Moreover, we find that the simulated telescope aperture efficiency is increased across the frequency range of the ISS after the optimisation.

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Boosting line intensity map signal-to-noise ratio with the Ly-α forest cross-correlation

Cited by 3 publications

References 84 publications

PRIYA: a new suite of Lyman-α forest simulations for cosmology

PRIYA: a new suite of Lyman-α forest simulations for cosmology

LATIS: Constraints on the Galaxy–Halo Connection at z ∼ 2.5 from Galaxy–Galaxy and Galaxy–Lyα Clustering

Optimisation-based alignment of wide-band integrated superconducting spectrometers for submillimeter astronomy

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