Physical Sciences and Mathematics Commons^™

The Disk Substructures At High Angular Resolution Project (Dsharp). I. Motivation, Sample, Calibration, And Overview, Sean M. Andrews, Jane Huang, Laura M. Pérez, Andrea Isella, Cornelis P. Dullemond, Nicolás T. Kurtovic, Viviana V. Guzmán, John M. Carpenter, David J. Wilner, Shangjia Zhang, Zhaohuan Zhu, Tilman Birstiel, Xue-Ning Bai, Myriam Benisty, A. Meredith Hughes, Karin I. Öberg, Luca Ricci

Physics & Astronomy Faculty Research

We introduce the Disk Substructures at High Angular Resolution Project (DSHARP), one of the initial Large Programs conducted with the Atacama Large Millimeter/submillimeter Array (ALMA). The primary goal of DSHARP is to find and characterize substructures in the spatial distributions of solid particles for a sample of 20 nearby protoplanetary disks, using very high resolution (~0 035, or 5 au, FWHM) observations of their 240 GHz (1.25 mm) continuum emission. These data provide a first homogeneous look at the small-scale features in disks that are directly relevant to the planet formation process, quantifying their prevalence, morphologies, spatial scales, spacings, symmetry, …

The Disk Substructures At High Angular Resolution Project (Dsharp). Ix. A High-Definition Study Of The Hd 163296 Planet-Forming Disk, Andrea Isella, Jane Huang, Sean M. Andrews, Cornelis P. Dellemond, Tilman Birnstiel, Shangjia Zhang, Zhaohuan Zhu, Viviana V. Guzmán, Laura M. Pérez, Xue-Ning Bai, Myriam Benisty, John M. Carpenter, Luca Ricci, David J. Wilner

Physics & Astronomy Faculty Research

The Atacama Large Millimeter/submillimeter Array observations of protoplanetary disks acquired by the Disk Substructure at High Angular Resolution Project resolve the dust and gas emission on angular scales as small as 3 astronomical units, offering an unprecedented detailed view of the environment where planets form. In this Letter, we present and discuss observations of the HD 163296 protoplanetary disk that imaged the 1.25 mm dust continuum and 12CO J = 2–1 rotational line emission at a spatial resolution of 4 and 10 au, respectively. The continuum observations resolve and allow us to characterize the previously discovered dust rings at radii …

The Disk Substructures At High Angular Resolution Project (Dsharp). Iii. Spiral Structures In The Millimeter Continuum Of The Elias 27, Im Lup, And Waoph 6 Disks, Jane Huang, Sean M. Andrews, Laura M. Pérez, Zhaohuan Zhu, Cornelis P. Dullemond, Andrea Isella, Myriam Benisty, Xue-Ning Bai, Tilman Birnstiel, John M. Carpenter, Viviana V. Guzmán, A. Meredith Hughes, Karin I. Öberg, Luca Ricci, David J. Wilner, Shangjia Zhang

Physics & Astronomy Faculty Research

We present an analysis of Atacama Large Millimeter/submillimeter Array 1.25 mm continuum observations of spiral structures in three protoplanetary disks from the Disk Substructures at High Angular Resolution Project. See full text for full abstract.

The Disk Substructures At High Angular Resolution Project (Dsharp). Ii. Characteristics Of Annular Substructures, Jane Huang, Sean M. Andrews, Cornelis P. Dellemond, Andrea Isella, Laura M. Pérez, Viviana V. Guzmán, Karin I. Öberg, Zhaohuan Zhu, Shangjia Zhang, Xue-Ning Bai, Myriam Benisty, Tilman Birstiel, John M. Carpenter, A. Meredith Hughes, Luca Ricci, Erik Weaver, David J. Wilner

Physics & Astronomy Faculty Research

The Disk Substructures at High Angular Resolution Project (DSHARP) used ALMA to map the 1.25 mm continuum of protoplanetary disks at a spatial resolution of ~5 au. We present a systematic analysis of annular substructures in the 18 single-disk systems targeted in this survey. No dominant architecture emerges from this sample; instead, remarkably diverse morphologies are observed. Annular substructures can occur at virtually any radius where millimeter continuum emission is detected and range in widths from a few astronomical units to tens of astronomical units. Intensity ratios between gaps and adjacent rings range from near-unity to just a few percent. …

The Disk Substructures At High Angular Resolution Project (Dsharp). Vii. The Planet–Disk Interactions Interpretation, Shangjia Zhang, Zhaohuan Zhu, Jane Huang, Viviana V. Guzmán, Sean M. Andrews, Tilman Birnstiel, Cornelis P. Dullemond, John M. Carpenter, Andrea Isella, Laura M. Pérez, Myriam Benisty, David J. Wilner, Clément Baruteau, Xue-Ning Bai, Luca Ricci

Physics & Astronomy Faculty Research

The Disk Substructures at High Angular Resolution Project (DSHARP) provides a large sample of protoplanetary disks with substructures that could be induced by young forming planets. To explore the properties of planets that may be responsible for these substructures, we systematically carry out a grid of 2D hydrodynamical simulations, including both gas and dust components. We present the resulting gas structures, including the relationship between the planet mass, as well as (1) the gaseous gap depth/width and (2) the sub/super-Keplerian motion across the gap. We then compute dust continuum intensity maps at the frequency of the DSHARP observations. We provide …

The Disk Substructures At High Angular Resolution Project (Dsharp). Vi. Dust Trapping In Thin-Ringed Protoplanetary Disks, Cornelis P. Dullemond, Tilman Birnstiel, Jane Huang, Nicolás T. Kurtovic, Sean M. Andrews, Viviana V. Guzmán, Laura M. Pérez, Andrea Isella, Zhaohuan Zhu, Myriam Benisty, David J. Wilner, Xue-Ning Bai, John M. Carpenter, Shangjia Zhang, Luca Ricci

Physics & Astronomy Faculty Research

A large fraction of the protoplanetary disks observed with ALMA display multiple well-defined and nearly perfectly circular rings in the continuum, in many cases with substantial peak-to-valley contrast. The DSHARP campaign shows that several of these rings are very narrow in radial extent. In this Letter we test the hypothesis that these dust rings are caused by dust trapping in radial pressure bumps, and if confirmed, put constraints on the physics of the dust trapping mechanism. We model this process analytically in 1D, assuming axisymmetry. By comparing this model to the data, we find that all rings are consistent with …

The Disk Substructures At High Angular Resolution Program (Dsharp). Viii. The Rich Ringed Substructures In The As 209 Disk, Viviana V. Guzmán, Jane Huang, Sean M. Andrews, Andrea Isella, Laura M. Pérez, John M. Carpenter, Cornelis P. Dullemond, Luca Ricci, Tilman Birnstiel, Shangjia Zhang, Zhaohuan Zhu, Xue-Ning Bai, Myriam Benisty, Karin I. Öberg, David J. Wilner

Physics & Astronomy Faculty Research

The Disk Substructures at High Angular Resolution Program (DSHARP). VIII. The Rich Ringed Substructures in the AS 209 Disk

The Disk Substructures At High Angular Resolution Project (Dsharp). Iv. Characterizing Substructures And Interactions In Disks Around Multiple Star Systems, Nicolás T. Kurtovic, Laura M. Pérez, Myriam Benisty, Zhaohuan Zhu, Shangjia Zhang, Jane Huang, Sean M. Andrews, Cornelis P. Dullemond, Andrea Isella, Xue-Ning Bai, John M. Carpenter, Viviana V. Guzmán, Luca Ricci, David J. Wilner

Physics & Astronomy Faculty Research

To characterize the substructures induced in protoplanetary disks by the interaction between stars in multiple systems, we study the 1.25 mm continuum and the 12CO(J = 2–1) spectral line emission of the triple systems HT Lup and AS 205, at scales of ≈5 au, as part of the "Disk Substructures at High Angular Resolution Project" (DSHARP). In the continuum emission, we find two symmetric spiral arms in the disk around AS 205 N, with a pitch angle of 14°, while the southern component AS 205 S, itself a spectroscopic binary, is surrounded by a compact inner disk and a bright …

The Disk Substructures At High Angular Resolution Project (Dsharp). X. Multiple Rings, A Misaligned Inner Disk, And A Bright Arc In The Disk Around The T Tauri Star Hd 143006, Laura M. Pérez, Myriam Benisty, Sean M. Andrews, Andrea Isella, Cornelis P. Dellemond, Jane Huang, Nicolás T. Kurtovic, Viviana V. Guzmán, Zhaohuan Zhu, Tilman Birnstiel, Shangjia Zhang, John M. Carpenter, David J. Wilner, Luca Ricci, Xue-Ning Bai, Erik Weaver, Karin I. Öberg

Physics & Astronomy Faculty Research

We present a detailed analysis of new Atacama Large Millimeter/submillimeter Array (ALMA) observations of the disk around the T-Tauri star HD 143006, which at 46 mas (7.6 au) resolution reveals new substructures in the 1.25 mm continuum emission. The disk resolves into a series of concentric rings and gaps, together with a bright arc exterior to the rings that resembles hydrodynamical simulations of a vortex and a bridge-like feature connecting the two innermost rings. Although our 12CO observations at similar spatial resolution do not show obvious substructure, they reveal an inner disk depleted of CO emission. From the continuum emission …

The Disk Substructures At High Angular Resolution Project (Dsharp). V. Interpreting Alma Maps Of Protoplanetary Disks In Terms Of A Dust Model, Tilman Birnstiel, Cornelis P. Dullemond, Zhaohuan Zhu, Sean M. Andrews, Xue-Ning Bai, David J. Wilner, John M. Carpenter, Jane Huang, Andrea Isella, Myriam Benisty, Laura M. Pérez, Shangjia Zhang

Physics & Astronomy Faculty Research

The Disk Substructures at High Angular Resolution Project (DSHARP) is the largest homogeneous high-resolution (~0 035, or ~5 au) disk continuum imaging survey with the Atacama Large Millimeter/submillimeter Array (ALMA) so far. In the coming years, many more disks will be mapped with ALMA at similar resolution. Interpreting the results in terms of the properties and quantities of the emitting dusty material is, however, a very non-trivial task. This is in part due to the uncertainty in the dust opacities, an uncertainty that is not likely to be resolved any time soon. It is also partly due to the fact …

Studying Galaxy Troughs And Ridges Using Weak Gravitational Lensing With The Kilo-Degree Survey, Margot M. Brouwer, Vasiliy Demchenko, Joachim Harnois-Déraps, Maciej Bilicki, Catherine Heymans, Henk Hoekstra, Konrad Kuijken, Mehmet Alpaslan, Sarah Brough, Yan Chuan Cai, Marcus V. Costa-Duarte, Andrej Dvornik, Thomas Erben, Hendrik Hildebrandt, Benne W. Holwerda, Peter Schneider, Cristóbal Sifón, Edo Van Uitert

Faculty Scholarship

We study projected underdensities in the cosmic galaxy density field known as 'troughs', and their overdense counterparts, which we call 'ridges'. We identify these regions using a bright sample of foreground galaxies from the photometric Kilo-Degree Survey (KiDS), specifically selected to mimic the spectroscopic Galaxy And Mass Assembly survey. Using background galaxies from KiDS, we measure the weak gravitational lensing profiles of the troughs/ridges. We quantify the amplitude of their lensing strength A as a function of galaxy density percentile rank P and galaxy overdensity δ, and find that the skewness in the galaxy density distribution is reflected in the …

Detecting Radio Agn Signatures In Red Geysers, Namrata Roy, Kevin Bundy, Wiphu Rujopakarn, Michele Cappellari, Francesco Belfiore, Renbin Yan, Tim Heckman, Matthew Bershady, Jenny Greene, Kyle Westfall, Niv Drory, Kate Rubin, David Law, Kai Zhang, Joseph Gelfand, Dmitry Bizyaev, David Wake, Karen Masters, Daniel Thomas, Cheng Li, Rogemar A. Riffel

Physics and Astronomy Faculty Publications

A new class of quiescent galaxies harboring possible AGN-driven winds has been discovered using spatially resolved optical spectroscopy from the ongoing SDSS-IV MaNGA survey. These galaxies, termed "red geysers," constitute 5%–10% of the local quiescent population and are characterized by narrow bisymmetric patterns in ionized gas emission features. Cheung et al. argued that these galaxies host large-scale AGN-driven winds that may play a role in suppressing star formation at late times. In this work, we test the hypothesis that AGN activity is ultimately responsible for the red geyser phenomenon. We compare the nuclear radio activity of the red geysers to …

Toward An Understanding Of Grb Prompt Emission Mechanism. Ii. Patterns Of Peak Energy Evolution And Their Connection To Spectral Lags, Z. Lucas Uhm, Bing Zhang, Judith Racusin

Physics & Astronomy Faculty Research

The prompt emission phase of gamma-ray bursts (GRBs) exhibits two distinct patterns of the peak energy (E p ) evolution, i.e., time-resolved spectral analyses of νF ν spectra of broad pulses reveal (1) "hard-to-soft" and (2) "flux-tracking" patterns of E p evolution in time, the physical origin of which still remains not well understood. We show here that these two patterns can be successfully reproduced within a simple physical model invoking synchrotron radiation in a bulk-accelerating emission region. We show further that the evolution patterns of the peak energy have, in fact, direct connections to the existence of two different …

Extreme Hbl Behavior Of Markarian 501 During 2012, P. T. Reynolds, Et. Al.

Physical Sciences Publications

Aims. We aim to characterize the multiwavelength emission from Markarian 501 (Mrk 501), quantify the energy-dependent variability, study the potential multiband correlations, and describe the temporal evolution of the broadband emission within leptonic theoretical scenarios.

Methods. We organized a multiwavelength campaign to take place between March and July of 2012. Excellent temporal coverage was obtained with more than 25 instruments, including the MAGIC, FACT and VERITAS Cherenkov telescopes, the instruments on board the Swift and Fermi spacecraft, and the telescopes operated by the GASP-WEBT collaboration.

Results. Mrk 501 showed a very high energy (VHE) gamma-ray flux above 0.2 TeV of …

Hubble Pancet: An Extended Upper Atmosphere Of Neutral Hydrogen Around The Warm Neptune Gj 3470b, Vincent Bourrier, Alain Lecavelier Des Etangs, David Ehrenreich, Jorge Sanz-Forcada, Romain Allart, Gilda E. Ballester, Lars A. Buchhave, Ofer Cohen, Drake Deming, Thomas M. Evans, Antonio García Muñoz, Gregory W. Henry, Tiffany Kataria, Panayotis Lavvas, Nikole K. Lewis, Mercedes López-Morales, Mark S. Marley, David K. Sing, Hannah R. Wakeford

Information Systems and Engineering Management Research Publications

GJ 3470b is a warm Neptune transiting an M-dwarf star at the edge of the evaporation desert. It offers the possibility of investigating how low-mass, close-in exoplanets evolve under the irradiation from their host stars. We observed three transits of GJ 3470b in the Lyman-α line with the Hubble Space Telescope (HST) as part of the Panchromatic Comparative Exoplanet Treasury (PanCET) program. Absorption signatures are detected with similar properties in all three independent epochs, with absorption depths of 35 ± 7% in the blue wing of the line, and 23 ± 5% in the red wing. The repeatability of these …

Inclined Massive Planets In A Protoplanetary Disc: Gap Opening, Disc Breaking, And Observational Signatures, Zhaohuan Zhu

Physics & Astronomy Faculty Research

We carry out 3D hydrodynamical simulations to study planet–disc interactions for inclined high-mass planets, focusing on the disc’s secular evolution induced by the planet. We find that, when the planet is massive enough and the induced gap is deep enough, the disc inside the planet’s orbit breaks from the outer disc. The inner and outer discs precess around the system’s total angular momentum vector independently at different precession rates, which causes significant disc misalignment. We derive the analytical formulae, which are also verified numerically, for: (1) the relationship between the planet mass and the depth/width of the induced gap, (2) …

Application Of Bradford’S Law Of Scattering On Research Publication In Astronomy & Astrophysics Of India, Satish Kumar, Senthilkumar R.

Library Philosophy and Practice (e-journal)

The present study is focused on examining the application of Bradford’s law of scattering on research articles published in the field of Astronomy & Astrophysics by Indian scientist during 1988-2017. The bibliographic data was retrieved from Web of Science (WoS) bibliographic data base for different period of time. Total 18,877 journal’s article have been published by Indian scientist in the field of Astronomy & Astrophysics during 1988-2017 which was further retrieved and analyzed separately for different blocks of 10 years as well as for 30 years consolidated too. The core journal of the field was identified. The Bradford law of …

On The Apparent Absence Of Wolf–Rayet+Neutron Star Systems: The Curious Case Of Wr124, Jesus A. Toala, Lidi Oskinova, W.R. Hamann, Richard Ignace, A.A. C. Sander, H. Todt, Y.H. Chu, M. A. Guerrero, R. Hainich, R. Hainich, J. M. Terrejon

ETSU Faculty Works

Among the different types of massive stars in advanced evolutionary stages is the enigmatic WN8h type. There are only a few Wolf–Rayet (WR) stars with this spectral type in our Galaxy. It has long been suggested that WN8h-type stars are the products of binary evolution that may harbor neutron stars (NS). One of the most intriguing WN8h stars is the runaway WR 124 surrounded by its magnificent nebula M1-67. We test the presence of an accreting NS companion in WR 124 using ~100 ks long observations by the Chandra X-ray observatory. The hard X-ray emission from WR 124 with a …

Search For Subsolar-Mass Ultracompact Binaries In Advanced Ligo's First Observing Run, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, M. A. Aloy, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier

Physics and Astronomy Faculty Publications and Presentations

We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2 M-1.0 M using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2 M, 0.2 M) ultracompact binaries to be less than 1.0×106 Gpc-3 yr-1 and the coalescence rate of a similar distribution of (1.0 M, 1.0 M) ultracompact binaries to be less than 1.9×104 Gpc-3 yr-1 (at 90% confidence). Neither black holes nor neutron stars are expected to …

Mirach’S Goblin: Discovery Of A Dwarf Spheroidal Galaxy Behind The Andromeda Galaxy, David Martínez-Delgado, Eva Grebel, Behnam Javanmardi, Walter Boschin, Nicolas Longeard, Julio Carballo-Bello, Dmitry Makarov, Michael Beasley, Giuseppe Donatiello, Martha Haynes, Duncan Forbes, Aaron Romanowsky

Faculty Publications

Context. It is of broad interest for galaxy formation theory to carry out a full inventory of the numbers and properties of dwarf galaxies, both satellite and isolated, in the Local Volume.Aims. Ultra-deep imaging in wide areas of the sky with small amateur telescopes can help to complete the census of these hitherto unknown low-surface-brightness galaxies, which cannot be detected by the current resolved stellar population and HI surveys. We report the discovery of Donatiello I, a dwarf spheroidal galaxy located one degree from the star Mirach (β And) in a deep image taken with an amateur telescope.Methods. The color-magnitude …

The Hst Pancet Program: Hints Of Na I And Evidence Of A Cloudy Atmosphere For The Inflated Hot Jupiter Wasp-52b, Munazza K. Alam, Nikolay Nikolov, Mercedes López-Morales, David K. Sing, Jayesh M. Goyal, Gregory W. Henry, Jorge Sanz-Forcada, Michael H. Williamson, Thomas M. Evans, Hannah R. Wakeford, Giovanni Bruno, Gilda E. Ballester, Kevin B. Stevenson, Nikole K. Lewis, Joanna K. Barstow, Vincent Bourrier, Lars A. Buchhave, David Ehrenreich, Antonio García Muñoz

Information Systems and Engineering Management Research Publications

We present an optical to near-infrared transmission spectrum of the inflated hot Jupiter WASP-52b using three transit observations from the Space Telescope Imaging Spectrograph mounted on the Hubble Space Telescope, combined with Spitzer/Infrared Array Camera photometry at 3.6 and 4.5 μm. Since WASP-52 is a moderately active (log(Lx/Lbol) = −4.7) star, we correct the transit light curves for the effect of stellar activity using ground-based photometric monitoring data from the All-sky Automated Survey for Supernovae (ASAS-SN) and Tennessee State University's Automatic Imaging Telescope. We bin the data in 38 spectrophotometric light curves from 0.29 to 4.5 μm and measure the …

Angular Momentum And Galaxy Formation Revisited: Scaling Relations For Disks And Bulges, S. Michael Fall, Aaron Romanowsky

Faculty Publications

We show that the stellar specific angular momentum j, mass M, and bulge fraction of normal galaxies of all morphological types are consistent with a simple model based on a linear superposition of independent disks and bulges. In this model, disks and bulges follow scaling relations of the form and with but offset from each other by a factor of 8 ± 2 over the mass range . Separate fits for disks and bulges alone give and , respectively. This model correctly predicts that galaxies follow a curved 2D surface in the 3D space of , , and . We …

Covariations Of Chromospheric And Photometric Variability Of The Young Sun Analogue Hd 30495: Evidence For And Interpretation Of Mid-Term Periodicities, Willie Soon, Victor M. Velasco Herrera, Rodolfo G. Cionco, S. Qiu, Sallie Baliunas, Ricky Egeland, Gregory W. Henry, Ivanka Charvátová

Information Systems and Engineering Management Research Publications

This study reports the synchronization between the chromospheric and photometric variability at time-scale of about 1.6–1.8 yr as observed for the young, rapidly rotating solar analogue HD 30495. In addition, HD 30495 may be presenting evidence of surface differential rotation at time-scales of about 11 d and 21 d, as well as the sunspot-like decadal cycles at 11–12 yr or so. We apply a new gapped wavelet method of time–frequency analysis for studying the variability in a new composite of the chromospheric S-index (1967–2018) and the longest photometric Δ(b + y)/2 index (1993–2018). We discuss and interpret our results in …

Gaps And Rings In An Alma Survey Of Disks In The Taurus Star-Forming Region, Feng Long, Paola Pinilla, Gregory J. Herczeg, Daniel Harsono, Giovanni Dipierro, Ilaria Pascucci, Nathan Hendler, Marco Tazzari, Enrico Ragusa, Colette Salyk, Suzan Edwards, Giuseppe Lodato, Gerrit Van De Plas, Doug Johnstone, Yao Liu, Yann Boehler, Sylvie Cabrit, Carlo F. Manara, Francois Menard, Gijs D. Mulders, Brunella Nisini, William J. Fischer, Elisabetta Rigliaco, Andrea Banzatti, Henning Avenhaus, Michael Gully-Santiago

Astronomy: Faculty Publications

Rings are the most frequently revealed substructure in ALMA dust observations of protoplanetary disks, but their origin is still hotly debated. In this paper, we identify dust substructures in 12 disks and measure their properties to investigate how they form. This subsample of disks is selected from a high-resolution (∼ 0.1200) ALMA 1.33 mm survey of 32 disks in the Taurus star-forming region, which was designed to cover a wide range of sub-mm brightness and to be unbiased to previously known substructures. While axisymmetric rings and gaps are common within our sample, spiral patterns and high contrast azimuthal asymmetries are …

Book Review: Life On Mars: What To Know Before We Go, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Life on Mars: what to know before we go. Princeton, 2018. 302p index ISBN 9780691180533, $29.95; ISBN 9781400889945 ebook, contact publisher for price.

Challenges With Large Transverse Momentum In Semi-Inclusive Deeply Inelastic Scattering, J. O. Gonzalez-Hernandez, T. C. Rogers, N. Sato, B. Wang

Physics Faculty Publications

We survey the current phenomenological status of semi-inclusive deeply inelastic scattering at moderate hard scales and in the limit of very large transverse momentum. As the transverse momentum becomes comparable to or larger than the overall hard scale, the differential cross sections should be calculable with fixed order perturbative QCD (pQCD) methods, while small transverse momentum (transverse-momentum-dependent factorization) approximations should eventually break down. We find large disagreement between HERMES and COMPASS data and fixed order calculations done with modern parton densities, even in regions of kinematics where such calculations should be expected to be very accurate. Possible interpretations are suggested.

A Plausible Resolution To Hilbert’S Failed Attempt To Unify Gravitation & Electromagnetism, Florentin Smarandache, Victor Christianto, Robert Neil Boyd

Branch Mathematics and Statistics Faculty and Staff Publications

In this paper, we explore the reasons why Hilbert’s axiomatic program to unify gravitation theory and electromagnetism failed and outline a plausible resolution of this problem. The latter is based on Gödel’s incompleteness theorem and Newton’s aether stream model.

Substellar And Low-Mass Dwarf Identification With Near-Infrared Imaging Space Observatories, Benne W. Holwerda, J. S. Bridge, R. Ryan, M. A. Kenworthy, N. Pirzkal, M. Andersen, S. Wilkins, R. Smit, S. R. Bernard, T. Meshkat, R. Steele, R. C. Bouwens

Faculty Scholarship

Aims. We aim to evaluate the near-infrared colors of brown dwarfs as observed with four major infrared imaging space observatories: the Hubble Space Telescope (HST), the James Webb Space Telescope (JWST), the Euclid mission, and the WFIRST telescope. Methods. We used the SPLAT SPEX/ISPEX spectroscopic library to map out the colors of the M-, L-, and T-type dwarfs. We have identified which color-color combination is optimal for identifying broad type and which single color is optimal to then identify the subtype (e.g., T0-9). We evaluated each observatory separately as well as the narrow-field (HST and JWST) and wide-field (Euclid and …

Cm-Wavelength Obserations Of Mwc 758: Resolved Dust Trapping In A Vortex, Simon Casassus, Sebastián Marino, Wladimir Lyra, Clément Baruteau, Matías Vidal, Alwyn Wootten, Sebastián Pérez, Felipe Alarcon, Marcelo Barraza, Miguel Cárcamo, Ruobing Dong, Anibal Sierra, Zhaohuan Zhu, Luca Ricci, Valentin Christiaens, Lucas Cieza

Physics & Astronomy Faculty Research

The large crescents imaged by ALMA in transition discs suggest that azimuthal dust trapping concentrates the larger grains, but centimetre–wavelengths continuum observations are required to map the distribution of the largest observable grains. A previous detection at ∼1 cm of an unresolved clump along the outer ring of MWC 758 (Clump 1), and buried inside more extended sub-mm continuum, motivates followup VLA observations. Deep multiconfiguration integrations reveal the morphology of Clump 1 and additional cm-wave components that we characterize via comparison with a deconvolution of recent 342 GHz data (∼1 mm). ... See full text for complete abstract.

Detection Of Helium In The Atmosphere Of The Exo-Neptune Hat-P-11b, Megan Mansfield, Jacob L. Bean, Antonija Oklopčić, Laura Kreidberg, Jean-Michel Désert, Eliza M. R. Kempton, Michael R. Line, Jonathan J. Fortney, Gregory W. Henry, Matthias Mallonn, Kevin B. Stevenson, Diana Dragomir, Romain Allart, Vincent Bourrier

Information Systems and Engineering Management Research Publications

The helium absorption triplet at a wavelength of 10833 Å has been proposed as a way to probe the escaping atmospheres of exoplanets. Recently this feature was detected for the first time using Hubble Space Telescope (HST) WFC3 observations of the hot Jupiter WASP-107b. We use similar HST/WFC3 observations to detect helium in the atmosphere of the hot Neptune HAT-P-11b at the 4σ confidence level. We compare our observations to a grid of 1D models of hydrodynamic escape to constrain the thermospheric temperatures and mass loss rate. We find that our data are best fit by models with high mass …