The cosmic microwave background & the epoch of galaxy formation

Deep observations of the cosmic microwave background (CMB) have been made at 10 GHz with beamwidths of 5° and 8° using a triple-beam technique, which greatly reduces atmospheric effects. Significant signals are detected with an rms of ΔT/T ~ 4×10−5. These signals could be intrinsic to the CMB and are providing fundamental information about galaxy formation in the early universe. A component of this 10 GHz emission may be coming from galactic synchrotron features. This galactic contribution will be elucidated in forthcoming 15 and 30 GHz observations.

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Clustering of hotspots in the cosmic microwave background

EPJ Web of Conferences ◽

10.1051/epjconf/201920609017 ◽

2019 ◽

Vol 206 ◽

pp. 09017

Author(s):

En Zuo Joel Low ◽

Abel Yang

Keyword(s):

Cosmic Microwave Background ◽

Galaxy Formation ◽

Equilibrium Distribution ◽

Negative Binomial ◽

Clustering Algorithms ◽

Quasi Equilibrium ◽

Microwave Background ◽

Temperature Maps ◽

Recombination Epoch ◽

Frequency Temperature

The physics behind the origin and composition of the Cosmic Microwave Background (CMB) is a well-established topic in the field of Cosmology. Literature on CMB anisotropies reveal consistency with Gaussianity [1], but these were conducted on full multi-frequency temperature maps. In this thesis, we utilise clustering algorithms to specifically conduct statistical analyses on the distribution of hotspots in the CMB. We describe a series of data processing and clustering methodologies conducted, with results that conclusively show that the counts-in-cells distribution of hotspots in the CMB does not follow a Poisson distribution. Rather, the distribution exhibits a much closer fit to both the Negative Binomial Distribution (NBD) and the Gravitational Quasi-Equilibrium Distribution (GQED). From this result, we conclude that structure likely existed in the early universe, from the period of the recombination Epoch, possibly opening new insights in the field of galaxy formation.

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Magnetic fields from cosmological bulk flows

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2189 ◽

2020 ◽

Vol 497 (3) ◽

pp. 3537-3541

Author(s):

J A R Cembranos ◽

A L Maroto ◽

H Villarrubia-Rojo

Keyword(s):

Magnetic Fields ◽

Cosmic Microwave Background ◽

Galaxy Formation ◽

Relative Velocity ◽

Background Level ◽

Bulk Flow ◽

Microwave Background ◽

Boltzmann Equations ◽

First Order ◽

Dynamo Mechanism

ABSTRACT We explore the possibility that matter bulk flows could generate the required vorticity in the electron–proton–photon plasma to source cosmic magnetic fields through the Harrison mechanism. We analyse the coupled set of perturbed Maxwell and Boltzmann equations for a plasma in which the matter and radiation components exhibit relative bulk motions at the background level. These background bulk motions induce a relative velocity between the matter and cosmic microwave background rest frames at the present time, i.e. a bulk flow, with an amplitude β. We find that, to first order in cosmological perturbations, bulk flows with velocities compatible with current Planck limits (β < 8.5 × 10−4 at $95{{\ \rm per\ cent}}$ CL) could generate magnetic fields with an amplitude 10−21 G on 10 kpc comoving scales at the time of completed galaxy formation that could be sufficient to seed a galactic dynamo mechanism.

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Deep 10 and 15 GHZ Searches for CMB Anisotropies

Highlights of Astronomy ◽

10.1017/s1539299600009138 ◽

1992 ◽

Vol 9 ◽

pp. 323-325

Author(s):

R. D. Davies ◽

A. N. Lasenby

Keyword(s):

Dark Matter ◽

Cosmic Microwave Background ◽

Early Universe ◽

Galaxy Formation ◽

Cold Dark Matter ◽

Galactic Structure ◽

Observational Cosmology ◽

Significant Progress ◽

Microwave Background ◽

Observing Systems

The search for anisotropies in the Cosmic Microwave Background (CMB) is fundamental to observational cosmology: it requires observations on a range of angular scales and at a range of frequencies to distinguish CMB structure from foreground galactic structure. We have made significant progress in setting new limits to CMB anisotropies on angular scales of 3°-12° using scaled observing systems at 10 and 15 GHz. This regime of angular scales is particularly matched to the predictions of Cold Dark Matter (CDM) and isocurvature scenarios of galaxy formation in the early Universe.

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The Cosmic Microwave Background

Symposium - International Astronomical Union ◽

10.1017/s0074180900159005 ◽

1987 ◽

Vol 124 ◽

pp. 31-53

Author(s):

R. B. Partridge

Keyword(s):

Angular Distribution ◽

Cosmic Microwave Background ◽

Galaxy Formation ◽

Large Scale ◽

Microwave Background ◽

Angular Scale ◽

Upper Limits

This review summarizes recent observational work on the cosmic microwave background, or 3 K radiation. Recent measurements of its spectrum and large-scale angular distribution are described, as well as searches for small angular scale fluctuations on arcsecond to degree scales. A few of the consequences of these measurements and upper limits for cosmology, astrophysics, and theories of galaxy formation are touched on here.

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What Radio Astronomy Can Tell us about Galaxy Formation

Proceedings of the International Astronomical Union ◽

10.1017/s1743921311022502 ◽

2010 ◽

Vol 6 (S277) ◽

pp. 75-78

Author(s):

Bruce Partridge

Keyword(s):

Star Formation ◽

Cosmic Microwave Background ◽

Galaxy Formation ◽

Radio Astronomy ◽

Large Scale ◽

Cosmological Parameters ◽

Microwave Background ◽

Molecular Line ◽

Galaxy Formation And Evolution ◽

Formation And Evolution

AbstractRadio astronomy, broadly interpreted, has made important contributions to the study of galaxy formation and evolution. Maps of the cosmic microwave background provide information on the seeds of large-scale structure, in addition to refined values of the cosmological parameters. Examples of contributions from more conventional radio astronomy include:–The use of radio observations to track star formation rates since they are not affected by dust obscuration as optical/UV observations are, and the use of molecular line observations to make purely “radio” redshift determinations.

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