T. M. Evans
A5050627999- Stellar, planetary, and galactic studies
- Pulsars and Gravitational Waves Research
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Geophysics and Gravity Measurements
- Astrophysical Phenomena and Observations
- Cosmology and Gravitation Theories
- Atmospheric Ozone and Climate
- Astronomical Observations and Instrumentation
- Astrophysics and Cosmic Phenomena
- Geophysics and Sensor Technology
- Spectroscopy and Laser Applications
- Space Exploration and Technology
- Radio Astronomy Observations and Technology
- Seismic Waves and Analysis
- High-pressure geophysics and materials
- Advanced Frequency and Time Standards
- Solar and Space Plasma Dynamics
- Atomic and Subatomic Physics Research
- Calibration and Measurement Techniques
- Planetary Science and Exploration
- Spacecraft and Cryogenic Technologies
- Statistical and numerical algorithms
LIGO Scientific Collaboration
2014-2024
Max Planck Institute for Astronomy
2021-2024
University of Newcastle Australia
2024
Oak Ridge National Laboratory
2017-2024
Massachusetts Institute of Technology
2018-2023
University of Oxford
2011-2022
Kavli Institute for Particle Astrophysics and Cosmology
2020-2022
Beatson West of Scotland Cancer Centre
2022
University of Glasgow
2022
Vassar College
2019-2021
The Laser Interferometer Gravitational Wave Observatory (LIGO) consists of two widely separated 4 km laser interferometers designed to detect gravitational waves from distant astrophysical sources in the frequency range 10 Hz kHz. first observation run Advanced LIGO detectors started September 2015 and ended January 2016. A strain sensitivity better than $10^{-23}/\sqrt{\text{Hz}}$ was achieved around 100 Hz. Understanding both fundamental technical noise critical for increasing observable...
Transmission spectroscopy, which consists of measuring the wavelength-dependent absorption starlight by a planet's atmosphere during transit, is powerful probe atmospheric composition. However, expected signal typically orders magnitude smaller than instrumental systematics and results are crucially dependent on treatment latter. In this paper, we propose new method to infer transit parameters in presence systematic noise using Gaussian processes, technique widely used machine learning...
We present 2,241 exoplanet candidates identified with data from the Transiting Exoplanet Survey Satellite (TESS) during its two-year prime mission. list these in TESS Objects of Interest (TOI) Catalog, which includes both new planet found by and previously-known planets recovered observations. describe process used to identify TOIs investigate characteristics candidates, discuss some notable discoveries. The TOI Catalog an unprecedented number small around nearby bright stars, are...
We present a primary transit observation for the ultra-hot (Teq ∼ 2400 K) gas giant expolanet WASP-121b, made using Hubble Space Telescope Wide Field Camera 3 in spectroscopic mode across 1.12–1.64 μm wavelength range. The 1.4 water absorption band is detected at high confidence (5.4σ) planetary atmosphere. also reanalyze ground-based photometric light curves taken B, r', and z' filters. Significantly deeper transits are measured these optical bandpasses relative to near-infrared...
Transmission spectroscopy1-3 of exoplanets has revealed signatures water vapour, aerosols and alkali metals in a few dozen exoplanet atmospheres4,5. However, these previous inferences with the Hubble Spitzer Space Telescopes were hindered by observations' relatively narrow wavelength range spectral resolving power, which precluded unambiguous identification other chemical species-in particular primary carbon-bearing molecules6,7. Here we report broad-wavelength 0.5-5.5 µm atmospheric...
WASP-39b is a hot Saturn-mass exoplanet with predicted clear atmosphere based on observations in the optical and infrared. Here we complete transmission spectrum of near-infrared (NIR) over three water absorption features Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) G102 (0.8-1.1 microns) G141 (1.1-1.7 spectroscopic grisms. We measure high amplitude H2O feature centered at 1.4 microns, smaller 0.95 1.2 maximum 2.4 planetary scale heights. incorporate these new NIR measurements...
Measuring the abundances of carbon and oxygen in exoplanet atmospheres is considered a crucial avenue for unlocking formation evolution exoplanetary systems. Access to an exoplanet's chemical inventory requires high-precision observations, often inferred from individual molecular detections with low-resolution space-based high-resolution ground-based facilities. Here we report medium-resolution (R$\sim$600) transmission spectrum atmosphere between 3-5 $\mu$m covering multiple absorption...
High-resolution Doppler-resolved spectroscopy has opened up a new window into the atmospheres of both transiting and non-transiting exoplanets. Here, we present VLT/UVES observations transit WASP-121b, an 'ultra-hot' Jupiter previously found to exhibit temperature inversion detections multiple species at optical wavelengths. We initial results using blue arm UVES ($\approx$3700-5000A), recovering clear signal neutral Fe in planet's atmosphere >8$\sigma$, which could contribute (or even fully...
Transmission spectroscopy provides insight into the atmospheric properties and consequently formation history, physics, chemistry of transiting exoplanets. However, obtaining precise inferences from transmission spectra requires simultaneously measuring strength shape multiple spectral absorption features a wide range chemical species. This has been challenging given precision wavelength coverage previous observatories. Here, we present spectrum Saturn-mass exoplanet WASP-39b obtained using...
Photochemistry is a fundamental process of planetary atmospheres that regulates the atmospheric composition and stability. However, no unambiguous photochemical products have been detected in exoplanet to date. Recent observations from JWST Transiting Exoplanet Early Release Science Program found spectral absorption feature at 4.05 $\mu$m arising SO$_2$ atmosphere WASP-39b. WASP-39b 1.27-Jupiter-radii, Saturn-mass (0.28 M$_J$) gas giant orbiting Sun-like star with an equilibrium temperature...
Abstract Measuring the metallicity and carbon-to-oxygen (C/O) ratio in exoplanet atmospheres is a fundamental step towards constraining dominant chemical processes at work and, if equilibrium, revealing planet formation histories. Transmission spectroscopy (for example, refs. 1,2 ) provides necessary means by abundances of oxygen- carbon-bearing species; however, this requires broad wavelength coverage, moderate spectral resolution high precision, which, together, are not achievable with...
Abstract Close-in giant exoplanets with temperatures greater than 2,000 K (‘ultra-hot Jupiters’) have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from Hubble Space Telescope (HST) and Spitzer 1–3 . However, previous studies yielded inconsistent results because small sizes spectral features limited information content data resulted in high sensitivity varying assumptions made treatment instrument systematics retrieval...
Abstract Hot Jupiters are among the best-studied exoplanets, but it is still poorly understood how their chemical composition and cloud properties vary with longitude. Theoretical models predict that clouds may condense on nightside molecular abundances can be driven out of equilibrium by zonal winds. Here we report a phase-resolved emission spectrum hot Jupiter WASP-43b measured from 5 μm to 12 JWST’s Mid-Infrared Instrument. The spectra reveal large day–night temperature contrast (with...
Abstract We present a comprehensive analysis of the Hubble Space Telescope observations atmosphere WASP-121 b, an ultra-hot Jupiter. After reducing transit, eclipse, and phase-curve with uniform methodology addressing biases from instrument systematics, sophisticated atmospheric retrievals are used to extract robust constraints on thermal structure, chemistry, cloud properties atmosphere. Our shows that consistent strong inversion beginning at ∼10 4 Pa dayside, solar subsolar metallicity Z...
Data collected by the GEO 600 and LIGO interferometric gravitational wave detectors during their first observational science run were searched for continuous waves from pulsar J1939+2134 at twice its rotation frequency. Two independent analysis methods used are demonstrated in this paper: a frequency domain method time method. Both achieve consistent null results, placing new upper limits on strength of pulsar's emission. A model emission mechanism is to interpret as constraint equatorial...
We measure the transmission spectrum of WASP-19b from three transits using low-resolution optical spectroscopy Hubble Space Telescope (HST) Imaging Spectrograph (STIS). The STIS spectra cover a wavelength range 0.29–1.03 μm, with resolving power R = 500. data are combined archival near-infrared HST Wide Field Camera 3 (WFC3) G141 grism, covering 1.087 to 1.687 130. reach signal-to-noise levels between 3000 and 11 000 in 0.1 μm bins when measuring 0.53–1.687 μm. WASP-19 is known be very...
We present HST optical transmission spectra of the transiting hot Jupiter WASP-12b, taken with STIS instrument. From spectra, we are able to decisively rule out prominent absorption by TiO in exoplanet's atmosphere. Strong pressure-broadened Na and K signatures also excluded, as significant metal-hydride features. compare our combined broadband spectrum a wide variety existing aerosol-free atmospheric models, though none satisfactory fits. However, do find that full can be described models...
We present an optical to near-infrared transmission spectrum of the hot Jupiter HAT-P-1b, based on HST observations, covering spectral regime from 0.29 1.027{\mu}m with STIS, which is coupled a recent WFC3 transit (1.087 1.687{\mu}m). derive refined physical parameters HAT-P-1 system, including improved orbital ephemeris. The shows strong absorption signature shortward 0.55{\mu}m, blueward slope into near-ultraviolet. detect atmospheric sodium at 3.3{\sigma} significance level, but find no...
We present a secondary eclipse observation for the hot Jupiter HD189733b across wavelength range 290-570nm made using Space Telescope Imaging Spectrograph on Hubble Telescope. measure geometric albedos of Ag = 0.40 \pm 0.12 290-450nm and < 450-570nm at 1-sigma confidence. The albedo decrease toward longer wavelengths is also apparent when six bins over same range. This can be interpreted as evidence optically thick reflective clouds dayside hemisphere with sodium absorption suppressing...
We report Gemini-South GMOS observations of the exoplanet system WASP-29 during primary transit as a test case for differential spectrophotometry. use multi-object spectrograph to observe target star and comparison simultaneously produce multiple light curves at varying wavelengths. The 'white' curve fifteen 'spectral' are analysed refine parameters transmission spectrum from 515 720nm. All exhibit time-correlated noise, which we model using variety techniques. These include simple noise...