An Absorption Feature in Observations with EDGES Mid-Band

• Raul Monsalve (Department of Physics and McGill Space Institute McGill University)

Room: Lecture Hall D I will present results from observations with the EDGES Mid-Band system. This instrument measured in 2018 the sky-averaged radio spectrum in the range ~60-120 MHz. It used a blade antenna that is ~30% smaller than the Low-Band antennas used for the measurements in Bowman et al. (2018). Despite the smaller antenna, in the Mid-Band spectrum we identify an absorption feature that is consistent with our Low-Band result. This consistency increases the confidence that this feature is not an instrumental artifact but instead a spectral property of the sky. In my talk I will describe the Mid-Band observations, instrument calibration, data modelling, and characteristics of the Mid-Band absorption signal.

Dark Matter in Light of the 21cm EDGES Signal

• Kovetz Ely (Ben Gurion Univ. )

Room: Lecture Hall D

Complementarity of CMB and 21cm for the study of dark matter properties and exotic reionization

• Vivian Poulin (Montpellier Univ. )

Room: Lecture Hall D In this talk, I will review how the CMB and 21cm can be used to study dark matter (DM) properties, as well as sources of exotic (early) reionization. I will first discuss how the CMB can provide strong constraints on scattering between DM and baryons, and probe the parameter space suggested by the EDGES anomaly. I will then introduce models that could reconcile the EDGES anomaly while being consistent with CMB observations. Secondly, I will explain how the CMB can be used to probe the existence of extra sources of ionization and heating, and compare existing constraints to what future 21cm experiment could do. I will also discuss the status in the Planck 2018 data of a hint for early exotic reionization originally suggested in earlier Planck release.

Neutrinos at 21 cm

• Silvia Pascoli (Durham University )

Room: Lecture Hall D

TBA

• Maria Archidiacono (Bologna Univ. )

Room: Lecture Hall D

Colloquium

• Lesgourgues Julien (RWTH Aachen U.)

Room: Lecture Hall D

TBA

• Saleem Zaroubi (University of Groningen)

Room: Lecture Hall D

Modeling the 21-cm signal from the Cosmic Dawn

• Andrei Mesinger (Scuola Normale Superiore)

Room: Lecture Hall D The birth of the first stars, black holes and galaxies heralded the end of the cosmic Dark Ages and the beginning of the Cosmic Dawn. The light from these objects heated and ionized almost every atom in existence, culminating in the Epoch of Reionization: the final major phase change of the Universe. This final frontier of astrophysical cosmology is undergoing a transition from an observationally-starved epoch to a "Big Data" field. This process is set to culminate with upcoming Square Kilometre Array interferometric observations of the redshifted 21-cm line: providing a 3D map of the first billion years of our Universe. With the SKA, we will be able to actually study the UV and X-ray properties of the first galaxies, as well as physical cosmology, which are encoded in the large-scale structure of the 21-cm signal. I will review the current status of observations of the EoR and Cosmic Dawn, before discussing the main challenges in modeling the 21-cm signal: a huge range of relevant scales and a large parameter space of astrophysical uncertainties. I will review how simulations have adapted to address these challenges. Finally, I will introduce a Bayesian forward-modeling framework capable of on-the-fly sampling of 3D simulations, allowing us to simultaneously infer the properties of the unseen first galaxies and physical cosmology encoded in the 21-cm signal.