First results on the Epoch of Reionization from First Light with SARAS 2

Abstract

Long wavelength spectral distortions in the Cosmic Microwave Background arising from the 21-cm transition in neutral Hydrogen are a key probe of Cosmic Dawn and the Epoch of Reionization. These features may reveal the nature of the first stars and ultra-faint galaxies that transformed the spin temperature and ionization state of the primordial gas. SARAS~2 is a spectral radiometer purposely designed for precision measurement of these monopole or all-sky global 21-cm spectral distortions. We use 63~hr night time observing of the radio background in the frequency band 110-200~MHz with the radiometer deployed at the Timbaktu Collective in Southern India to derive likelihoods for plausible redshifted 21-cm signals predicted by theoretical models. First light with SARAS 2 disfavors the class of models that feature weak X-ray heating (with $f_X\le 0.1$) and rapid reionization (with peak $\frac{d{T}_b}{dz}\ge 120\text{mK per unit redshift interval}$ ).

6 pages, 5 figures, accepted for publication in ApJ Letters

References in corpus (12)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Observational constraints on Cosmic Reionization
• Model-independent evidence in favor of an end to reionization by z~6
• The Global 21 Centimeter Background from High Redshifts
• Upper limits on the 21-cm Epoch of Reionization power spectrum from one night with LOFAR
• First Season MWA EoR Power Spectrum Results at Redshift 7
• First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z ~ 7
• The Global 21-cm Signal in the Context of the High-z Galaxy Luminosity Function
• BIGHORNS - Broadband Instrument for Global HydrOgen ReioNisation Signal
• Foreground Model and Antenna Calibration Errors in the Measurement of the Sky-Averaged λ21 cm Signal at z~20
• GMOSS: All-sky model of spectral radio brightness based on physical components and associated radiative processes
• Selection between foreground models for global 21-cm experiments

Cited by in corpus (92)

• An absorption profile centred at 78 megahertz in the sky-averaged spectrum
• Possible interaction between baryons and dark-matter particles revealed by the first stars
• Improved upper limits on the 21-cm signal power spectrum of neutral hydrogen at $\mathbf{z}\approx 9.1$ from LOFAR
• Data Analysis for Precision 21 cm Cosmology
• First Results from HERA Phase I: Upper Limits on the Epoch of Reionization 21 cm Power Spectrum
• Signature of Excess Radio Background in the 21-cm Global Signal and Power Spectrum
• Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations
• What does the first highly-redshifted 21-cm detection tell us about early galaxies?
• Design and characterization of the Large-Aperture Experiment to Detect the Dark Age (LEDA) radiometer systems
• Constraining Baryon--Dark Matter Scattering with the Cosmic Dawn 21-cm Signal
• Tighter Limits on Dark Matter Explanations of the Anomalous EDGES 21cm Signal
• The redshifted 21-cm signal in the EDGES low-band spectrum
• Results from EDGES High-Band: I. Constraints on Phenomenological Models for the Global $21$ cm Signal
• The first power spectrum limit on the 21-cm signal of neutral hydrogen during the Cosmic Dawn at z=20-25 from LOFAR
• The REACH radiometer for detecting the 21-cm hydrogen signal from redshift 7.5 to 28
• Constraining the intergalactic medium at $z\approx$ 9.1 using LOFAR Epoch of Reionization observations
• SARAS 2 constraints on global 21-cm signals from the Epoch of Reionization
• The influence of streaming velocities and Lyman-Werner radiation on the formation of the first stars
• SARAS 2: A Spectral Radiometer for probing Cosmic Dawn and the Epoch of Reionization through detection of the global 21 cm signal
• Tight Constraints on the Excess Radio Background at $z=9.1$ from LOFAR
• Interpreting LOFAR 21-cm signal upper limits at z~9.1 in the context of high-z galaxy and reionisation observations
• Emulating the Global 21-cm Signal from Cosmic Dawn and Reionization
• Exploring reionisation and high-z galaxy observables with recent multi-redshift MWA upper limits on the 21-cm signal
• Results from EDGES High-Band: III. New Constraints on Parameters of the Early Universe
• The Epoch of IGM heating by early sources of X-rays
• Unique Signatures of Population III Stars in the Global 21-cm Signal
• Spectral Index of the Diffuse Radio Background Between 50 and 100 MHz
• Constraining the state of the intergalactic medium during the Epoch of Reionization using MWA 21-cm signal observations
• First upper limits on the 21 cm signal power spectrum from cosmic dawn from one night of observations with NenuFAR
• A fast estimator for the bispectrum and beyond - A practical method for measuring non-Gaussianity in 21-cm maps
• Astrophysical Constraints from the SARAS3 non-detection of the Cosmic Dawn Sky-Averaged 21-cm Signal
• SARAS 3 CD/EoR Radiometer: Design and Performance of the Receiver
• Charting the Parameter Space of the 21-cm Power Spectrum
• Lyman-$\alpha$ coupling and heating at Cosmic Dawn
• Mapper of the IGM spin temperature: instrument overview
• Results from EDGES High-Band: II. Constraints on Parameters of Early Galaxies
• Measuring the topology of reionization with Betti numbers
• A 21-cm power spectrum at 48 MHz, using the Owens Valley Long Wavelength Array
• Global 21-cm signal extraction from foreground and instrumental effects I: Pattern recognition framework for separation using training sets
• Astrophysical radio background cannot explain the EDGES 21-cm signal: constraints from cooling of non-thermal electrons
• The AARTFAAC Cosmic Explorer: observations of the 21-cm power spectrum in the EDGES absorption trough
• Validation of EDGES Low-Band Antenna Beam Model
• On the contamination of the global 21~cm signal from polarized foregrounds
• Probing relic neutrino decays with 21 cm cosmology
• Global 21-cm Signal Extraction from Foreground and Instrumental Effects II: Efficient and Self-Consistent Technique for Constraining Nonlinear Signal Models
• Assessment of the Projection-induced Polarimetry Technique for Constraining the Foreground Spectrum in Global 21 cm Cosmology
• Lunar Orbit Measurement of Cosmic Dawn 21 cm Global Spectrum
• Lost Horizon: Quantifying the Effect of Local Topography on Global 21-cm Cosmology Data Analysis
• Simulations of Galactic polarized synchrotron emission for Epoch of Reionization observations
• Spectral index of the Galactic foreground emission in the 50-87 MHz range
• On dark matter - dark radiation interaction and cosmic reionization
• CosmoReionMC: A package for estimating cosmological and astrophysical parameters using CMB, Lyman-α absorption and global 21 cm data
• Impact of inhomogeneous reionization on the Lyman-α forest
• Constraining Warm Dark Matter and Pop III stars with the Global 21-cm Signal
• Modelling the Galactic Foreground and Beam Chromaticity for Global 21-cm Cosmology
• Measuring the global 21-cm signal with the MWA-I: improved measurements of the Galactic synchrotron background using lunar occultation
• Exploiting synergies between JWST and cosmic 21-cm observations to uncover star formation in the early Universe
• SARAS CD/EoR Radiometer: Design and performance of the Digital Correlation Spectrometer
• Discovering the Sky at the Longest Wavelengths with Small Satellite Constellations
• Cosmological implications of the composite spectra of galactic X-ray binaries constructed using MAXI data
• A General Bayesian Framework to Account for Foreground Map Errors in Global 21-cm Experiments
• Using Artificial Neural Networks to extract the 21-cm Global Signal from the EDGES data
• Probing early universe through redshifted 21-cm signal: Modelling and observational challenges
• Forecasts and Statistical Insights for Line Intensity Mapping Cross-Correlations: A Case Study with 21cm x [CII]
• Parametrizing the Reionization History with the Redshift Midpoint, Duration, and Asymmetry
• Constraints on the state of the IGM at $z\sim 8-10$ using redshifted 21-cm observations with LOFAR
• Extracting the Global 21-cm signal from Cosmic Dawn and Epoch of Reionization in the presence of Foreground and Ionosphere
• Statistical Detection of IGM Structures during Cosmic Reionization using Absorption of the Redshifted 21 cm line by HI against Compact Background Radio Sources
• A galaxy-free phenomenological model for the 21-cm power spectrum during reionization
• Transient RFI environment of LOFAR-LBA at 72-75 MHz: Impact on ultra-widefield AARTFAAC Cosmic Explorer observations of the redshifted 21-cm signal
• Cosmic Radio Background from Primordial Black Holes at Cosmic Dawn
• Probing the intergalactic medium during the Epoch of Reionization using 21-cm signal power spectra
• Effects of model incompleteness on the drift-scan calibration of radio telescopes
• The duration of reionization constrains the ionizing sources
• Square Kilometre Array Science Data Challenge 3a: foreground removal for an EoR experiment
• A detailed exploration of the EDGES 21 cm absorption anomaly and axion-induced cooling
• STARFIRE: An algorithm for estimating radio frequency interference in orbits around Earth
• Sensitivity of the Global 21-cm Signal to Dark Matter-Baryon Scattering
• Low-Frequency Radio Recombination Lines Away From the Inner Galactic Plane
• Singular spectrum analysis of time series data from low frequency radiometers, with an application to SITARA data
• Measuring the global 21-cm signal with the MWA-II: improved characterisation of lunar-reflected radio frequency interference
• Detecting Cosmic 21 cm Global Signal Using an Improved Polynomial Fitting Algorithm
• In Search of Global 21-cm Signal using Artificial Neural Network in light of ARCADE 2
• Confronting global 21-cm signal with ${\mathbb{Z}}_3$ symmetric dark matter models
• The Effects of Dark Matter Annihilation and Dark Matter-Baryon Velocity Offsets at Cosmic Dawn
• The Anomalous 21-cm Absorption at High Redshifts
• System design and calibration of SITARA -- a global 21 cm short spacing interferometer prototype
• Constraints on the velocity dispersion of Dark Matter from Cosmology and new bounds on scattering from the Cosmic Dawn
• An SBC-based controller and processor for the laboratory model of PRATUSH Digital Receiver
• Probing 21cm cosmology and radiative neutrino decays
• A New Boundary Condition on Reionization
• A Comprehensive Bayesian re-analysis of the SARAS2 data from the Epoch of Reionization