Publications (57)
A Minimalist Feedback-Regulated Model for Galaxy Formation During the Epoch of Reionization
Steven Furlanetto, Jordan Mirocha, Richard Mebane +1
Near-infrared surveys have now determined the luminosity functions of galaxies at 6<z<9 to impressive precision and identified a number of candidates at even earlier times. Here we…
LIMFAST. III. Timing Cosmic Reionization with the 21 cm and Near-Infrared Backgrounds
Guochao Sun, Adam Lidz, Tzu-Ching Chang +2
The timeline of cosmic reionization remains uncertain despite sustained efforts to study how the ionizing output of early galaxies shaped the intergalactic medium (IGM). Using the…
Signatures of reionization feedback in the near-infrared background
Jordan Mirocha, Adrian Liu, Paul La Plante
The reionization of the intergalactic medium at redshifts is expected to have a lasting impact on galaxies residing in low-mass dark matter halos. Unable to accrete or…
Sensitivity of the Global 21-cm Signal to Dark Matter-Baryon Scattering
Aryan Rahimieh, Priyank Parashari, Rui An +3
With current and upcoming experiments on the horizon, the global 21-cm signal can open up new avenues for probing dark matter (DM) physics at redshifts that are otherwise inaccessi…
Prospects for distinguishing galaxy evolution models with surveys at redshifts
Jordan Mirocha
Many semi-empirical galaxy formation models have recently emerged to interpret high- galaxy luminosity functions and make predictions for future galaxy surveys. A common approac…
Constraining Warm Dark Matter and Pop III stars with the Global 21-cm Signal
Joshua J. Hibbard, Jordan Mirocha, David Rapetti +3
Upcoming ground and space-based experiments may have sufficient accuracy to place significant constraints upon high-redshift star formation, Reionization, and dark matter (DM) usin…
Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations
The HERA Collaboration, Zara Abdurashidova, Tyrone Adams +92
We report the most sensitive upper limits to date on the 21 cm epoch of reionization power spectrum using 94 nights of observing with Phase I of the Hydrogen Epoch of Reionization…
Astro 2020 Science White Paper: Fundamental Cosmology in the Dark Ages with 21-cm Line Fluctuations
Steven Furlanetto, Judd D. Bowman, Jordan Mirocha +43
The Dark Ages are the period between the last scattering of the cosmic microwave background and the appearance of the first luminous sources, spanning approximately 1100 < z < 30.…
On the expected purity of photometric galaxy surveys targeting the Cosmic Dawn
Steven R. Furlanetto, Jordan Mirocha
Over the last three decades, photometric galaxy selection using the Lyman-break technique has transformed our understanding of the high-z Universe, providing large samples of galax…
Relatively Fast and Reasonably Furious: Evidence for Increased Burstiness in Smaller Halos at Cosmic Dawn
Julian B. Muñoz, John Chisholm, Guochao Sun +7
We introduce an effective framework to model star-formation burstiness and use it to jointly fit galaxy UV luminosity functions (UVLFs), clustering, and H/UV ratios, providing…
Mapping Cosmic Dawn and Reionization: Challenges and Synergies
Marcelo A. Alvarez, Anastasia Fialkov, Paul La Plante +47
Cosmic dawn and the Epoch of Reionization (EoR) are among the least explored observational eras in cosmology: a time at which the first galaxies and supermassive black holes formed…
Interpreting the Global 21-cm Signal from High Redshifts. I. Model Independent Constraints
Jordan Mirocha, Geraint J. A. Harker, Jack O. Burns
The sky-averaged (global) 21-cm signal is a powerful probe of the intergalactic medium (IGM) prior to the completion of reionization. However, it has so far been unclear that even…
Seeking dark matter with -ray attenuation
José Luis Bernal, Andrea Caputo, Gabriela Sato-Polito +2
The flux of high-energy astrophysical rays is attenuated by the production of electron-positron pairs from scattering off of extragalactic background light (EBL). We use the m…
Prospects for 21cm-Galaxy Cross-Correlations with HERA and the Roman High-Latitude Survey
Paul La Plante, Jordan Mirocha, Adélie Gorce +2
The cross-correlation between the 21 cm field and the galaxy distribution is a potential probe of the Epoch of Reionization (EoR). The 21 cm signal traces neutral gas in the interg…
Astro2020 Science White Paper: First Stars and Black Holes at Cosmic Dawn with Redshifted 21-cm Observations
Jordan Mirocha, Daniel Jacobs, Josh Dillon +39
The "cosmic dawn" refers to the period of the Universe's history when stars and black holes first formed and began heating and ionizing hydrogen in the intergalactic medium (IGM).…
The relative constraining power of the high- 21-cm dipole and monopole signals
Jordan Mirocha, Chris Anderson, Tzu-Ching Chang +2
The 21-cm background is a promising probe of early star formation and black hole activity. While a slew of experiments on the ground seek to detect the 21-cm monopole and spatial f…
Cosmology with the Highly Redshifted 21cm Line
Adrian Liu, James Aguirre, Yacine Ali-Haimoud +47
In addition to being a probe of Cosmic Dawn and Epoch of Reionization astrophysics, the 21cm line at is also a powerful way to constrain cosmology. Its power derives from sev…
Reionization after JWST: a photon budget crisis?
Julian B. Muñoz, Jordan Mirocha, John Chisholm +2
New James Webb Space Telescope (JWST) observations are revealing the first galaxies to be prolific producers of ionizing photons, which we argue gives rise to a tension between dif…
A physically-motivated template set for high-z galaxy SED fitting
Judah Luberto, Steven Furlanetto, Jordan Mirocha
We introduce a new physically-motivated spectral template set for fitting the spectral energy distributions (SEDs) of high-z galaxies. We use the public galaxy formation code ARES…
CIBER 4th flight fluctuation analysis: Measurements of near-IR auto- and cross-power spectra on arcminute to sub-degree scales
Richard M. Feder, James J. Bock, Yun-Ting Cheng +10
We present new anisotropy measurements in the near-infrared (NIR) for angular multipoles using imaging data at 1.1 m and 1.8 m from the fourth flight of the…
Global 21-cm Signal Extraction from Foreground and Instrumental Effects II: Efficient and Self-Consistent Technique for Constraining Nonlinear Signal Models
David Rapetti, Keith Tauscher, Jordan Mirocha +1
We present the completion of a data analysis pipeline that self-consistently separates global 21-cm signals from large systematics using a pattern recognition technique. In the fir…
Parametrizations of the global 21-cm signal and parameter estimation from single-dipole experiments
Geraint J. A. Harker, Jordan Mirocha, Jack O. Burns +1
One approach to extracting the global 21-cm signal from total-power measurements at low radio frequencies is to parametrize the different contributions to the data and then fit for…
Spectral Map Making with SPHEREx
Ari J. Cukierman, Shuang-Shuang Chen, Jae Hwan Kang +23
We present map-making methodologies and preliminary spectral data cubes for SPHEREx, a NASA Explorer mission that launched in March 2025 and has been performing an all-sky near-inf…
A Space-Based Observational Strategy for Characterizing the First Stars and Galaxies Using the Redshifted 21-cm Global Spectrum
Jack O. Burns, Richard Bradley, Keith Tauscher +19
The redshifted 21-cm monopole is expected to be a powerful probe of the epoch of the first stars and galaxies (). The global 21-cm signal is sensitive to the thermal and i…
Revealing the formation histories of the first stars with the cosmic near-infrared background
Guochao Sun, Jordan Mirocha, Richard H. Mebane +1
The cosmic near-infrared background (NIRB) offers a powerful integral probe of radiative processes at different cosmic epochs, including the pre-reionization era when metal-free, P…
Decoding the X-ray Properties of Pre-Reionization Era Sources
Jordan Mirocha
Evolution in the X-ray luminosity -- star formation rate (-SFR) relation could provide the first evidence of a top-heavy stellar initial mass function in the early universe, a…
A halo model approach for the 21-cm power spectrum at cosmic dawn
Aurel Schneider, Sambit K. Giri, Jordan Mirocha
Prior to the epoch of reionisation, the 21-cm signal of the cosmic dawn is dominated by the Lyman- coupling and gas temperature fluctuations caused by the first sources of radi…
Balancing the efficiency and stochasticity of star formation with dust extinction in z > 10 galaxies observed by JWST
Jordan Mirocha, Steven R. Furlanetto
Early observations with JWST indicate an over-abundance of bright galaxies at redshifts relative to Hubble-calibrated model predictions. More puzzling still is the a…
A galaxy-free phenomenological model for the 21-cm power spectrum during reionization
Jordan Mirocha, Julian B. Muñoz, Steven R. Furlanetto +2
Upper limits from the current generation of interferometers targeting the 21-cm signal from high redshifts have recently begun to rule out physically realistic, though still extrem…
Effects of self-consistent rest-ultraviolet colours in semi-empirical galaxy formation models
Jordan Mirocha, Charlotte Mason, Daniel P. Stark
Connecting the observed rest-ultraviolet (UV) luminosities of high- galaxies to their intrinsic luminosities (and thus star formation rates) requires correcting for the presence…
A Roadmap for Astrophysics and Cosmology with High-Redshift 21 cm Intensity Mapping
The Hydrogen Epoch of Reionization Array, Collaboration, James E. Aguirre +29
In this white paper, we lay out a US roadmap for high-redshift 21 cm cosmology (30 < z < 6) in the 2020s. Beginning with the currently-funded HERA and MWA Phase II projects and adv…
The Global 21-cm Signal in the Context of the High-z Galaxy Luminosity Function
Jordan Mirocha, Steven R. Furlanetto, G. Sun
Motivated by recent progress in studies of the high- Universe, we build a new model for the global 21-cm signal that is explicitly calibrated to measurements of the galaxy lumin…
The SPHEREx Satellite Mission
James J. Bock, Asad M. Aboobaker, Joseph Adamo +111
SPHEREx, a NASA explorer satellite launched on 11 March 2025, is carrying out the first all-sky near-infrared spectral survey. The satellite observes in 102 spectral bands from 0.7…
Systematic uncertainties in models of the cosmic dawn
Jordan Mirocha, Henri Lamarre, Adrian Liu
Models of the reionization and reheating of the intergalactic medium (IGM) at redshifts continue to grow more sophisticated in anticipation of near-future 21-cm, cosm…
Interpreting the Global 21-cm Signal from High Redshifts. II. Parameter Estimation for Models of Galaxy Formation
Jordan Mirocha, Geraint J. A. Harker, Jack O. Burns
Following our previous work, which related generic features in the sky-averaged (global) 21-cm signal to properties of the intergalactic medium, we now investigate the prospects fo…
Bursty star formation during the Cosmic Dawn driven by delayed stellar feedback
Steven R. Furlanetto, Jordan Mirocha
In recent years, several analytic models have demonstrated that simple assumptions about halo growth and feedback-regulated star formation can match the (limited) existing observat…
Optimized Multi-Frequency Spectra for Applications in Radiative Feedback and Cosmological Reionization
Jordan Mirocha, Stephen Skory, Jack O. Burns +1
The recent implementation of radiative transfer algorithms in numerous hydrodynamics codes has led to a dramatic improvement in studies of feedback in various astrophysical environ…
HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on Astrophysics and Cosmology During the Epoch of Reionization
The HERA Collaboration, Zara Abdurashidova, James E. Aguirre +81
Recently, the Hydrogen Epoch of Reionization Array (HERA) collaboration has produced the experiment's first upper limits on the power spectrum of 21-cm fluctuations at z~8 and 10.…
The Effects of Population III X-ray and Radio Backgrounds on the Cosmological 21-cm Signal
Richard H. Mebane, Jordan Mirocha, Steven R. Furlanetto
We investigate the effects of Population III (Pop III) stars and their remnants on the cosmological 21-cm global signal. By combining a semi-analytic model of Pop III star formatio…
Astro2020 Science White Paper: Insights Into the Epoch of Reionization with the Highly-Redshifted 21-cm Line
Steven Furlanetto, Chris L. Carilli, Jordan Mirocha +47
The epoch of reionization, when photons from early galaxies ionized the intergalactic medium about a billion years after the Big Bang, is the last major phase transition in the Uni…
Breaking degeneracies in the first galaxies with clustering
Julian B. Muñoz, Jordan Mirocha, Steven Furlanetto +1
The high-redshift galaxy UV luminosity function (UVLF) has become essential for understanding the formation and evolution of the first galaxies. Yet, UVLFs only measure galaxy abun…
Cosmic Dawn and Reionization: Astrophysics in the Final Frontier
Asantha Cooray, James Aguirre, Yacine Ali-Haimoud +71
The cosmic dawn and epoch of reionization mark the time period in the universe when stars, galaxies, and blackhole seeds first formed and the intergalactic medium changed from neut…
High-mass X-ray binaries in nearby metal-poor galaxies: on the contribution to nebular HeII emission
Peter Senchyna, Daniel P. Stark, Jordan Mirocha +4
Despite significant progress both observationally and theoretically, the origin of high-ionization nebular HeII emission in galaxies dominated by stellar photoionization remains un…
Constraining bursty star formation histories with galaxy UV and H luminosity functions and clustering
Guochao Sun, Julian B. Muñoz, Jordan Mirocha +1
The observed prevalence of galaxies exhibiting bursty star formation histories (SFHs) at has created new challenges and opportunities for understanding their formation…
Astro2020 Science White Paper: Synergies Between Galaxy Surveys and Reionization Measurements
Steven Furlanetto, Adam Beardsley, Chris L. Carilli +47
The early phases of galaxy formation constitute one of the most exciting frontiers in astrophysics. It is during this era that the first luminous sources reionize the intergalactic…
NASA Probe Study Report: Farside Array for Radio Science Investigations of the Dark ages and Exoplanets (FARSIDE)
Jack O. Burns, Gregg Hallinan, Jim Lux +16
This is the final report submitted to NASA for a Probe-class concept study of the "Farside Array for Radio Science Investigations of the Dark ages and Exoplanets" (FARSIDE), a low…
Astrophysics from the 21-cm background
Jordan Mirocha
This chapter describes the astrophysics encoded by the 21-cm background. We begin with a brief introduction to the radiative transfer and ionization chemistry relevant to the high-…
What does the first highly-redshifted 21-cm detection tell us about early galaxies?
Jordan Mirocha, Steven R. Furlanetto
The Experiment to Detect the Global Epoch of Reionization Signature (EDGES) recently reported a strong 21-cm absorption signal relative to the cosmic microwave background at $z \si…
Structure Formation and the Global 21-cm Signal in the Presence of Coulomb-like Dark Matter-Baryon Interactions
Trey Driskell, Ethan O. Nadler, Jordan Mirocha +6
Many compelling dark matter (DM) scenarios feature Coulomb-like interactions between DM particles and baryons, in which the cross section for elastic scattering scales with relativ…
A Lunar Farside Low Radio Frequency Array for Dark Ages 21-cm Cosmology
Jack Burns, Gregg Hallinan, Tzu-Ching Chang +20
An array of low-frequency dipole antennas on the lunar farside surface will probe a unique, unexplored epoch in the early Universe called the Dark Ages. It begins at Recombination…
First Results from HERA Phase II
The HERA Collaboration, Zuhra Abdurashidova, Tyrone Adams +83
We report the first upper limits on the power spectrum of 21-cm fluctuations during the Epoch of Reionization and Cosmic Dawn from Phase II of the Hydrogen Epoch of Reionization Ar…
Unique Signatures of Population III Stars in the Global 21-cm Signal
Jordan Mirocha, Richard H. Mebane, Steven R. Furlanetto +2
We investigate the effects of Population III stars on the sky-averaged 21-cm background radiation, which traces the collective emission from all sources of ultraviolet and X-ray ph…
Machine-learning recovery of foreground wedge-removed 21-cm light cones for high- galaxy mapping
Jacob Kennedy, Jonathan Colaço Carr, Samuel Gagnon-Hartman +3
Upcoming experiments will map the spatial distribution of the 21-cm signal over three-dimensional volumes of space during the Epoch of Reionization (EoR). Several methods have been…
The importance of galaxy formation histories in models of reionization
Jordan Mirocha, Paul La Plante, Adrian Liu
Upcoming galaxy surveys and 21-cm experiments targeting high redshifts are highly complementary probes of galaxy formation and reionization. However, in order to exped…
Exploring the role of the halo mass function for inferring astrophysical parameters during reionisation
Bradley Greig, David PrelogoviÄ, Jordan Mirocha +3
The detection of the 21-cm signal at will reveal insights into the properties of the first galaxies responsible for driving reionisation. To extract this information, w…
The Persistence of Population III Star Formation
Richard H. Mebane, Jordan Mirocha, Steven R. Furlanetto
We present a semi-analytic model of star formation in the early universe, beginning with the first metal-free stars. By employing a completely feedback-limited star formation presc…
Canada and the SKA from 2020-2030
Kristine Spekkens, Cynthia Chiang, Roland Kothes +57
This white paper submitted for the 2020 Canadian Long-Range Planning process (LRP2020) presents the prospects for Canada and the Square Kilometre Array (SKA) from 2020-2030, focuss…