Search Results - "ROGERS, Alan E. E"
-
1
An absorption profile centred at 78 megahertz in the sky-averaged spectrum
Published in Nature (London) (01-03-2018)“…The 21-cm absorption profile is detected in the sky-averaged radio spectrum, but is much stronger than predicted, suggesting that the primordial gas might have…”
Get full text
Journal Article -
2
Jet-Launching Structure Resolved Near the Supermassive Black Hole in M87
Published in Science (American Association for the Advancement of Science) (19-10-2012)“…Approximately 10% of active galactic nuclei exhibit relativistic jets, which are powered by the accretion of matter onto supermassive black holes. Although the…”
Get full text
Journal Article -
3
Event-horizon-scale structure in the supermassive black hole candidate at the Galactic Centre
Published in Nature (04-09-2008)“…The cores of most galaxies are thought to harbour supermassive black holes, which power galactic nuclei by converting the gravitational energy of accreting…”
Get full text
Journal Article -
4
Reply to Hills et al
Published in Nature (London) (01-12-2018)“…[...]their choice to use it over the full band was not justified. Judd D. Bowman1·, Alan E. E. Rogers2, Raul A. Monsalve1'3'4'5'6, Thomas J. Mozdzen1 &…”
Get full text
Journal Article -
5
Results from EDGES High-band. I. Constraints on Phenomenological Models for the Global 21 cm Signal
Published in The Astrophysical journal (20-09-2017)“…We report constraints on the global 21 cm signal due to neutral hydrogen at redshifts 14.8 ≥ z ≥ 6.5 . We derive our constraints from low-foreground…”
Get full text
Journal Article -
6
Results from EDGES High-Band. III. New Constraints on Parameters of the Early Universe
Published in The Astrophysical journal (10-04-2019)“…We present new constraints on parameters of cosmic dawn and the epoch of reionization derived from the EDGES High-Band spectrum (90-190 MHz). The parameters…”
Get full text
Journal Article -
7
Results from EDGES High-band. II. Constraints on Parameters of Early Galaxies
Published in The Astrophysical journal (10-08-2018)“…We use the sky-average spectrum measured by EDGES High-band (90-190 MHz) to constrain parameters of early galaxies independent of the absorption feature at 78…”
Get full text
Journal Article -
8
Detecting Flaring Structures in Sagittarius A with High-Frequency VLBI
Published in The Astrophysical journal (10-04-2009)“…The super-massive black hole candidate, Sagittarius A*, exhibits variability from radio to X-ray wavelengths on timescales that correspond to <10 Schwarzschild…”
Get full text
Journal Article -
9
CALIBRATION OF THE EDGES HIGH-BAND RECEIVER TO OBSERVE THE GLOBAL 21 cm SIGNATURE FROM THE EPOCH OF REIONIZATION
Published in The Astrophysical journal (20-01-2017)“…ABSTRACT The EDGES High-Band experiment aims to detect the sky-average brightness temperature of the 21 cm signal from the epoch of reionization in the…”
Get full text
Journal Article -
10
Toward Empirical Constraints on the Global Redshifted 21 cm Brightness Temperature During the Epoch of Reionization
Published in The Astrophysical journal (20-03-2008)“…Preliminary results are presented from a simple, single-antenna experiment designed to measure the all-sky radio spectrum between 100 and 200 MHz. The system…”
Get full text
Journal Article -
11
Low-frequency Radio Recombination Lines Away from the Inner Galactic Plane
Published in The Astronomical journal (01-01-2024)“…Abstract Diffuse radio recombination lines (RRLs) in the Galaxy are possible foregrounds for redshifted 21 cm experiments. We use EDGES drift scans centered at…”
Get full text
Journal Article -
12
Resolved magnetic-field structure and variability near the event horizon of Sagittarius A
Published in Science (American Association for the Advancement of Science) (04-12-2015)“…Near a black hole, differential rotation of a magnetized accretion disk is thought to produce an instability that amplifies weak magnetic fields, driving…”
Get full text
Journal Article -
13
Ground-based Ku-band microwave observations of ozone in the polar middle atmosphere
Published in Atmospheric measurement techniques (20-04-2022)“…Ground-based observations of 11.072 GHz atmospheric ozone (O3) emission have been made using the Ny-Ålesund Ozone in the Mesosphere Instrument (NAOMI) at the…”
Get full text
Journal Article -
14
Adapting a Cryogenic Sapphire Oscillator for Very Long Baseline Interferometry
Published in Publications of the Astronomical Society of the Pacific (01-05-2011)“…Extension of very long baseline interferometry (VLBI) to observing wavelengths shorter than 1.3 mm provides exceptional angular resolution (∼20 μas ∼ 20 μ…”
Get full text
Journal Article -
15
One-Port Direct/Reverse Method for Characterizing VNA Calibration Standards
Published in IEEE transactions on microwave theory and techniques (01-08-2016)“…This paper introduces a one-port method for estimating model parameters of vector network analyzer calibration standards. The method involves measuring the…”
Get full text
Journal Article -
16
Detecting Changing Polarization Structures in Sagittarius A with High Frequency VLBI
Published in The Astrophysical journal (01-12-2009)“…Sagittarius A* is the source of near infrared, X-ray, radio, and (sub)millimeter emission associated with the supermassive black hole at the Galactic Center…”
Get full text
Journal Article -
17
A lower limit of Δz > 0.06 for the duration of the reionization epoch
Published in Nature (London) (09-12-2010)“…A new look at the reionization of the Universe A new generation of radio telescopes is making it possible to observe the redshifted 21-centimetre spectral line…”
Get full text
Journal Article -
18
Estimating Solar Flux Density at Low Radio Frequencies Using a Sky Brightness Model
Published in Solar physics (01-06-2017)“…Sky models have been used in the past to calibrate individual low radio frequency telescopes. In this article we generalize this approach from a single antenna…”
Get full text
Journal Article -
19
Radio Frequencies: Policy and Management
Published in IEEE transactions on geoscience and remote sensing (01-10-2013)“…The electromagnetic spectrum is a valued shared resource. Its scientific use allows us to learn about our universe, measure and monitor our planet, and…”
Get full text
Journal Article -
20
A Bayesian approach to modelling spectrometer data chromaticity corrected using beam factors – I. Mathematical formalism
Published in Monthly notices of the Royal Astronomical Society (23-03-2023)“…ABSTRACT Accurately accounting for spectral structure in spectrometer data induced by instrumental chromaticity on scales relevant for detection of the 21-cm…”
Get full text
Journal Article