Joshua Marvil
A5005948499- Radio Astronomy Observations and Technology
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Cosmology and Gravitation Theories
- Astrophysical Phenomena and Observations
- Superconducting and THz Device Technology
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Molecular Spectroscopy and Structure
- Geophysics and Gravity Measurements
- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Microwave Engineering and Waveguides
- Dark Matter and Cosmic Phenomena
- Precipitation Measurement and Analysis
- Adaptive optics and wavefront sensing
National Radio Astronomy Observatory
2015-2023
Astronomy and Space
2015-2022
Commonwealth Scientific and Industrial Research Organisation
2015-2022
Australia Telescope National Facility
2019
New Mexico Institute of Mining and Technology
2008-2015
University of California, Santa Barbara
2005-2008
High Altitude Observatory
2005
CASA, the Common Astronomy Software Applications, is primary data processing software for Atacama Large Millimeter/submillimeter Array (ALMA) and Karl G. Jansky Very (VLA), frequently used also other radio telescopes. The CASA can handle from single-dish, aperture-synthesis, Long Baseline Interferometery (VLBI) One of its core functionalities to support calibration imaging pipelines ALMA, VLA, VLA Sky Survey (VLASS), Nobeyama 45m telescope. This paper presents a high-level overview basic...
The Very Large Array Sky Survey (VLASS) is a synoptic, all-sky radio sky survey with unique combination of high angular resolution ($\approx$2.5"), sensitivity (a 1$\sigma$ goal 70 $\mu$Jy/beam in the coadded data), full linear Stokes polarimetry, time domain coverage, and wide bandwidth (2-4 GHz). first observations began September 2017, observing for will finish 2024. VLASS use approximately 5500 hours on Karl G. Jansky (VLA) to cover whole visible VLA (Declination $>-40^{\circ}$), total...
Abstract We present the data and initial results from first pilot survey of Evolutionary Map Universe (EMU), observed at 944 MHz with Australian Square Kilometre Array Pathfinder (ASKAP) telescope. The covers $270 \,\mathrm{deg}^2$ an area covered by Dark Energy Survey, reaching a depth 25–30 $\mu\mathrm{Jy\ beam}^{-1}$ rms spatial resolution $\sim$ 11–18 arcsec, resulting in catalogue 220 000 sources, which 180 are single-component sources. Here we together (where available) optical...
We report the discovery of a new 21-cm HI absorption system using commissioning data from Boolardy Engineering Test Array Australian Square Kilometre Pathfinder (ASKAP). Using 711.5 - 1015.5 MHz band ASKAP we were able to conduct blind search for line in continuous redshift range between $z = 0.4$ and 1.0, which has, until now, remained largely unexplored. The is detected at 0.44$ towards GHz-peaked spectrum radio source PKS B1740$-$517 demonstrates ASKAP's excellent capability performing...
We used dedicated SRG/eROSITA X-ray, ASKAP/EMU radio, and DECam optical observations of a 15 sq.deg region around the interacting galaxy cluster system A3391/95 to study warm-hot gas in outskirts filaments, surrounding large-scale structure its formation process. relate expectations from cosmological hydrodynamic simulations Magneticum suite. trace irregular morphology main clusters their centers out well beyond characteristic radii, $r_{200}$. Between two systems, we observe an emission...
Abstract We present new observations of the central 1 kpc M82 starburst obtained with James Webb Space Telescope near-infrared camera instrument at a resolution θ ∼ 0.″05–0.″1 (∼1–2 pc). The data comprises images in three mostly continuum filters (F140M, F250M, and F360M), that contain [Fe ii ] (F164N), H 2 v = → 0 (F212N), 3.3 μ m polycyclic aromatic hydrocarbon (PAH) feature (F335M). find prominent plumes PAH emission extending outward from region, together network complex filamentary...
The Shapley Supercluster ($\langle z \rangle\approx0.048$) contains several tens of gravitationally bound clusters and groups, making it is an ideal subject for radio studies cluster mergers. We used new high sensitivity observations to investigate the less energetic events mass assembly in from supercluster down galactic scales. created total intensity images full region between A 3558 3562, $\sim 230$ 1650$ MHz, using ASKAP, MeerKAT GMRT, with sensitivities ranging 6$ 100$ $\mu$Jy...
ABSTRACT We use data from the pilot observations of EMU/POSSUM surveys to study ‘missing supernova remnant (SNR) problem’, discrepancy between number Galactic SNRs that have been observed, and are estimated exist. The Evolutionary Map Universe (EMU) Polarization Sky Survey Universe’s Magnetism (POSSUM) radio sky conducted using Australian Square Kilometre Array Pathfinder (ASKAP). report on properties seven known in joint field, with an approximate longitude latitude 323° ≤ l 330° −4° b 2°,...
We have acquired radio-continuum data between 70 MHz and 48 GHz for a sample of 19 southern starburst galaxies at moderate redshifts (0.067 < z 0.227) with the aim separating synchrotron free–free emission components. Using Bayesian framework, we find radio continuum is rarely characterized well by single power law, instead often exhibiting low-frequency turnovers below 500 MHz, steepening mid to high frequencies, flattening frequencies where begins dominate over emission. These higher order...
The pre-merging system of galaxy clusters Abell 3391-Abell 3395 located at a mean redshift 0.053 has been observed 1 GHz in an ASKAP/EMU Early Science observation as well X-rays with eROSITA. projected separation the X-ray peaks two is $\sim$50$'$ or $\sim$ 3.1 Mpc. Here we present inventory interesting radio sources this field around cluster merger. While eROSITA observations provide clear indications bridge thermal gas between clusters, neither ASKAP nor MWA show any diffuse emission...
Using the Boolardy Engineering Test Array of Australian Square Kilometre Pathfinder (ASKAP BETA), we have carried out first $z = 0 - 1$ survey for HI and OH absorption towards gravitationally lensed quasars PKSB1830$-$211 MGJ0414$+$0534. Although detected all previously reported intervening systems PKSB1830$-$211, in case MGJ0414+0534 three were not found, indicating that original identifications may been confused with radio frequency interference. Given sensitivity our data, find detection...
Abstract We report on neutral hydrogen (H i) observations of the NGC 7232 group with Australian Square Kilometre Array Pathfinder (ASKAP). These were conducted as part Wide-field ASKAP L-Band Legacy All-sky Blind surveY (WALLABY) Early Science program an array 12 antennas equipped Phased Feeds, which used to form 36 beams map a field view 30 deg2. Analysing subregion central beams, we detect 17 H i sources. Eleven these detections are identified galaxies and have stellar counterparts, five...
We investigate the spectral shape of total continuum radiation, between 74 MHz and 5 GHz (400–6 cm in wavelength), for a large sample bright galaxies. take advantage overlapping survey coverage VLA Low-Frequency Sky Survey, Westerbork Northern NRAO Green Bank 6 Survey to achieve significantly better resolution, sensitivity, size compared prior efforts this nature. For our 250 galaxies we measure mean index, α, −0.69 1.4 4.85 GHz, −0.55 325 −0.45 MHz, which amounts detection curvature...
We present two new radio continuum images from the Australian Square Kilometre Array Pathfinder (ASKAP) survey in direction of Small Magellanic Cloud (SMC). These are part Evolutionary Map Universe (EMU) Early Science Project (ESP) and Large Clouds. The source lists produced these contain sources observed at 960 MHz (4489 sources) 1320 (5954 with a bandwidth 192 beam sizes 30.0"x30.0" 16.3"x15.1", respectively. median Root Mean Squared (RMS) noise values 186$\mu$Jy beam$^{-1}$ (960 MHz)...
We present a pilot search for variable and transient sources at 1.4 GHz with the Australian Square Kilometre Array Pathfinder (ASKAP). The was performed in 30 deg$^{2}$ area centred on NGC 7232 galaxy group over 8 epochs observed near-daily cadence. yielded nine potential sources, rejecting null hypothesis that flux densities of these do not change 99.9% confidence. These displayed density variations modulation indices m $\geq 0.1$ above our limit 1.5 mJy. They are identified to be compact...
Massive protostars generate strong radiation feedback, which may help set the mass they achieve by end of accretion process. Studying such feedback is therefore crucial for understanding formation massive stars. We report discovery a photoionized bipolar outflow towards protostar G45.47+0.05 using high-resolution observations at 1.3 mm with Atacama Large Millimeter/Submillimeter Array (ALMA) and 7 Karl G. Jansky Very (VLA). By modeling free-free continuum, ionized found to be...
Abstract We present a detailed analysis of the radio galaxy PKS $2250{-}351$ , giant 1.2 Mpc projected size, its host galaxy, and environment. use data from Murchison Widefield Array, upgraded Giant Metre-wavelength Radio Telescope, Australian Square Kilometre Array Pathfinder, Australia Telescope Compact to model jet power age. Optical IR come Galaxy And Mass Assembly (GAMA) survey provide information on GAMA spectroscopy confirms that lies at $z=0.2115$ in irregular, likely unrelaxed,...
The intrinsic thermal (free–free) and non-thermal (synchrotron) emission components that comprise the radio continuum of galaxies represent unique, dust-free measures star formation rates (SFR). Such high SFR will dominate deepest current future surveys. We disentangle six ultraluminous infrared (LFIR > 1012.5 L⊙) at redshifts 0.2 ≤ z 0.5 22 IR selected galaxies. Radio data over a wide frequency range (0.8 < ν 10 GHz) are fitted with star-forming galaxy model comprising components....
Context. Infrared-faint radio sources (IFRS) are a class of radio-loud (RL) active galactic nuclei (AGN) at high redshifts (z ≥ 1.7) that characterised by their relative infrared faintness, resulting in enormous radio-to-infrared flux density ratios up to several thousand.
Abstract We have observed the G23 field of Galaxy AndMass Assembly (GAMA) survey using Australian Square Kilometre Array Pathfinder (ASKAP) in its commissioning phase to validate performance telescope and characterise detected galaxy populations. This observation covers ~48 deg 2 with synthesised beam 32.7 arcsec by 17.8 at 936MHz, ~39 15.8 12.0 1320MHz. At both frequencies, root-mean-square (r.m.s.) noise is ~0.1 mJy/beam. combine these radio observations GAMA data, which includes...
We study centimeter continuum emission of eight high- and intermediate-mass protostars that are part the SOFIA Massive (SOMA) Star Formation Survey, thus building extended spectral energy distributions (SEDs) from radio to infrared. discuss morphology seen in images, which mostly derived archival VLA data, relation infrared morphology. use SEDs test new models high-mass star formation including radiative disk-wind feedback associated free-free dust (Tanaka, Tan, & Zhang 2016). show...
We present the first sky maps from BEAST (Background Emission Anisotropy Scanning Telescope) experiment. consists of a 2.2 m off-axis Gregorian telescope fed by cryogenic millimeter wavelength focal plane currently consisting six Q band (40 GHz) and two Ka (30 scalar feed horns feeding HEMT amplifiers. Data were collected balloon-borne flights in 2000, followed lengthy ground observing campaign 3.8 km altitude University California White Mountain Research Station. This paper reports initial...
The Background Emission Anisotropy Scanning Telescope (BEAST) is a millimeter wavelength experiment designed to generate maps of fluctuations in the cosmic microwave background (CMB). telescope composed an off-axis Gregorian optical system with 2.2 m primary that focuses collected radiation onto array cryogenically cooled high electron mobility transistor (HEMT) receivers. This six corrugated scalar feed horns Q band (38 45 GHz) and two more Ka (26 36 one Q-band connected ortho-mode...
ABSTRACT In the broad context of Australian Square Kilometer Array Pathfinder (ASKAP) early-science phase and preparation for related surveys, we report first radio observations towards Galactic plane. The targeted field was chosen to encompass entire SCORPIO survey, one several pathfinder projects Evolutionary Map Universe survey planned with ASKAP. were carried out in 2018 January at a central frequency 912 MHz, 15 operational antennas, covered total area about 40 square degrees three...