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2019

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Full-Text Articles in Astrophysics and Astronomy

The Distribution Of Ultra-Diffuse And Ultra-Compact Galaxies In The Frontier Fields, Steven Janssens, Roberto Abraham, Jean Brodie, Duncan Forbes, Aaron Romanowsky Dec 2019

The Distribution Of Ultra-Diffuse And Ultra-Compact Galaxies In The Frontier Fields, Steven Janssens, Roberto Abraham, Jean Brodie, Duncan Forbes, Aaron Romanowsky

Faculty Publications

Large low-surface-brightness galaxies have recently been found to be abundant in nearby galaxy clusters. In this paper, we investigate these ultra-diffuse galaxies (UDGs) in the six Hubble Frontier Fields galaxy clusters: A2744, MACS J0416.1−2403, MACS J0717.5+3745, MACS J1149.5+2223, AS1063, and A370. These are the most massive (1–3 × 1015 M ⊙) and distant (0.308 < z < 0.545) systems in which this class of galaxy has yet been discovered. We estimate that the clusters host of the order of ~200–1400 UDGs inside the virial radius (R 200), consistent with the UDG abundance–halo-mass relation found in the local universe, and suggest that UDGs may be formed in clusters. Within each cluster, however, we find that UDGs are not evenly distributed. Instead their projected spatial distributions are lopsided, and they are deficient in the regions of highest mass density as traced by gravitational lensing. While the deficiency of UDGs in central regions is not surprising, the lopsidedness is puzzling. The UDGs, and their lopsided spatial distributions, may be associated with known substructures late in their infall into the clusters, meaning that we find evidence both for formation of UDGs in clusters and for UDGs falling into clusters. We also investigate the ultra-compact dwarfs (UCDs) residing in the clusters, and find that the spatial distributions of UDGs and UCDs appear anticorrelated. Around 15% of UDGs exhibit either compact nuclei or nearby point sources. Taken together, these observations provide additional evidence for a picture in which at least some UDGs are destroyed in dense cluster environments and leave behind a residue of UCDs.


Stellar Chromospheric Activity And Age Relation From Open Clusters In The Lamost Survey, Jiajun Zhang, Terry Oswalt, Jingkun Zhao, Xiangsong Fang, Gang Zhao, Xilong Liang, Xianhao Ye, Jing Zhong Dec 2019

Stellar Chromospheric Activity And Age Relation From Open Clusters In The Lamost Survey, Jiajun Zhang, Terry Oswalt, Jingkun Zhao, Xiangsong Fang, Gang Zhao, Xilong Liang, Xianhao Ye, Jing Zhong

Publications

No abstract provided.


Bayesian Characterization Of Main-Sequence Binaries In The Old Open Cluster Ngc 188, Roger E. Cohen, Ted Von Hippel, Aaron M. Geller Dec 2019

Bayesian Characterization Of Main-Sequence Binaries In The Old Open Cluster Ngc 188, Roger E. Cohen, Ted Von Hippel, Aaron M. Geller

Publications

The binary fractions of open and globular clusters yield powerful constraints on their dynamical state and evolutionary history. We apply publicly available Bayesian analysis tools to a UBV RIJHKS photometric catalog of the open cluster NGC 188 to detect and characterize photometric binaries along the cluster main sequence. This technique has the advantage of self-consistently handling photometric errors, missing data in various bandpasses, and star-by-star prior constraints on cluster membership. Simulations are used to verify uncertainties and quantify selection biases in our analysis, illustrating that among binaries with mass ratios >0.5, we recover the binary fraction to better than …


Precise Mass Determination Of Spt-Cl J2106-5844, The Most Massive Cluster At Z > 1, Jinhyub Kim, M. James Jee, Saul Perlmutter, Brian Hayden, David Rubin, Xiaosheng Huang, Greg Aldering, Jongwan Ko Dec 2019

Precise Mass Determination Of Spt-Cl J2106-5844, The Most Massive Cluster At Z > 1, Jinhyub Kim, M. James Jee, Saul Perlmutter, Brian Hayden, David Rubin, Xiaosheng Huang, Greg Aldering, Jongwan Ko

Physics and Astronomy

We present a detailed high-resolution weak-lensing study of SPT-CL J2106-5844 at z = 1.132, claimed to be the most massive system discovered at z > 1 in the South Pole Telescope Sunyaev–Zel'dovich survey. Based on the deep imaging data from the Advanced Camera for Surveys and Wide Field Camera 3 on board the Hubble Space Telescope, we find that the cluster mass distribution is asymmetric, composed of a main clump and a subclump ~640 kpc west thereof. The central clump is further resolved into two smaller northwestern and southeastern substructures separated by ~150 kpc. We show that this rather complex …


Transmission Spectroscopy Of Wasp-79b From 0.6 To 5.0 Μm, Kristin S. Sotzen, Kevin B. Stevenson, David K. Sing, Brian M. Kilpatrick, Hannah R. Wakeford, Joseph C. Filippazzo, Nikole K. Lewis, Sarah M. Hörst, Mercedes López-Morales, Gregory W. Henry, Lars A. Buchhave, David Ehrenreich, Jonathan D. Fraine, Antonio García Muñoz, Rahul Jayaraman, Panayotis Lavvas, Alain Lecavelier Des Etangs, Mark S. Marley, Nikolay Nikolov, Alexander D. Rathcke, Jorge Sanz-Forcada Dec 2019

Transmission Spectroscopy Of Wasp-79b From 0.6 To 5.0 Μm, Kristin S. Sotzen, Kevin B. Stevenson, David K. Sing, Brian M. Kilpatrick, Hannah R. Wakeford, Joseph C. Filippazzo, Nikole K. Lewis, Sarah M. Hörst, Mercedes López-Morales, Gregory W. Henry, Lars A. Buchhave, David Ehrenreich, Jonathan D. Fraine, Antonio García Muñoz, Rahul Jayaraman, Panayotis Lavvas, Alain Lecavelier Des Etangs, Mark S. Marley, Nikolay Nikolov, Alexander D. Rathcke, Jorge Sanz-Forcada

Information Systems and Engineering Management Research Publications

As part of the Panchromatic Exoplanet Treasury program, we have conducted a spectroscopic study of WASP-79b, an inflated hot Jupiter orbiting an F-type star in Eridanus with a period of 3.66 days. Building on the original WASP and TRAPPIST photometry of Smalley et al., we examine Hubble Space Telescope (HST)/Wide Field Camera 3 (WFC3) (1.125–1.650 μm), Magellan/Low Dispersion Survey Spectrograph (LDSS)-3C (0.6–1 μm) data, and Spitzer data (3.6 and 4.5 μm). Using data from all three instruments, we constrain the water abundance to be −2.20 ≤ log(H2O) ≤ −1.55. We present these results along with the results of an atmospheric …


Quantum-Enhanced Advanced Ligo Detectors In The Era Of Gravitational-Wave Astronomy, M. Tse, Haocun Yu, N. Kijbunchoo, A. Fernandez-Galiana, P. Dupej, L. Barsotti, C. D. Blair, D. D. Brown, S. E. Dwyer, Karla E. Ramirez Dec 2019

Quantum-Enhanced Advanced Ligo Detectors In The Era Of Gravitational-Wave Astronomy, M. Tse, Haocun Yu, N. Kijbunchoo, A. Fernandez-Galiana, P. Dupej, L. Barsotti, C. D. Blair, D. D. Brown, S. E. Dwyer, Karla E. Ramirez

Physics and Astronomy Faculty Publications and Presentations

The Laser Interferometer Gravitational Wave Observatory (LIGO) has been directly detecting gravitational waves from compact binary mergers since 2015. We report on the first use of squeezed vacuum states in the direct measurement of gravitational waves with the Advanced LIGO H1 and L1 detectors. This achievement is the culmination of decades of research to implement squeezed states in gravitational-wave detectors. During the ongoing O3 observation run, squeezed states are improving the sensitivity of the LIGO interferometers to signals above 50 Hz by up to 3 dB, thereby increasing the expected detection rate by 40% (H1) and 50% (L1).


New Foundation In The Sciences: Physics Without Sweeping Infinities Under The Rug, Florentin Smarandache, Victor Christianto, Robert Neil Boyd Dec 2019

New Foundation In The Sciences: Physics Without Sweeping Infinities Under The Rug, Florentin Smarandache, Victor Christianto, Robert Neil Boyd

Branch Mathematics and Statistics Faculty and Staff Publications

It is widely known among the Frontiers of physics, that “sweeping under the rug” practice has been quite the norm rather than exception. In other words, the leading paradigms have strong tendency to be hailed as the only game in town. For example, renormalization group theory was hailed as cure in order to solve infinity problem in QED theory. For instance, a quote from Richard Feynman goes as follows: “What the three Nobel Prize winners did, in the words of Feynman, was "to get rid of the infinities in the calculations. The infinities are still there, but now they can …


Detection Of A Low-Mass Stellar Companion To The Accelerating A2iv Star Hr 1645, Robert J. De Rosa, Eric L. Nielsen, Julien Rameau, Gaspard Duchêne, Alexandra Z. Greenbaum, Jason J. Wang, S. Mark Ammons, Vanessa P. Bailey, Travis Barman, Joanna Bulger, Jeffrey Chilcote, Tara Cotten, Rene Doyon, Thomas M. Esposito, Michael P. Fitzgerald, Katherine B. Follette, Benjamin L. Gerard, Stephen J. Goodsell, James R. Graham, Pascale Hibon, Justin Hom, Li Wei Hung, Patrick Ingraham, Paul Kalas, Quinn Konopacky, James E. Larkin, Bruce Macintosh, Jérôme Maire, Franck Marchis, Mark S. Marley, Christian Marois, Stanimir Metchev, Kimberly Ward-Duong, Et Al Dec 2019

Detection Of A Low-Mass Stellar Companion To The Accelerating A2iv Star Hr 1645, Robert J. De Rosa, Eric L. Nielsen, Julien Rameau, Gaspard Duchêne, Alexandra Z. Greenbaum, Jason J. Wang, S. Mark Ammons, Vanessa P. Bailey, Travis Barman, Joanna Bulger, Jeffrey Chilcote, Tara Cotten, Rene Doyon, Thomas M. Esposito, Michael P. Fitzgerald, Katherine B. Follette, Benjamin L. Gerard, Stephen J. Goodsell, James R. Graham, Pascale Hibon, Justin Hom, Li Wei Hung, Patrick Ingraham, Paul Kalas, Quinn Konopacky, James E. Larkin, Bruce Macintosh, Jérôme Maire, Franck Marchis, Mark S. Marley, Christian Marois, Stanimir Metchev, Kimberly Ward-Duong, Et Al

Astronomy: Faculty Publications

The ∼500 Myr A2IV star HR 1645 has one of the most significant low-amplitude accelerations of nearby early-type stars measured from a comparison of the Hipparcos and Gaia astrometric catalogs. This signal is consistent with either a stellar companion with a moderate mass ratio (q ∼ 0.5) on a short period (P < 1 yr), or a substellar companion at a separation wide enough to be resolved with ground-based high-contrast imaging instruments; long-period equal-mass ratio stellar companions that are also consistent with the measured acceleration are excluded with previous imaging observations. The small but significant amplitude of the acceleration made HR 1645 a promising candidate for targeted searches for brown dwarf and planetary-mass companions around nearby, young stars. In this paper we explore the origin of the astrometric acceleration by modeling the signal induced by a wide-orbit M8 companion discovered with the Gemini Planet Imager, as well as the effects of an inner short-period spectroscopic companion discovered a century ago but not since followed up. We present the first constraints on the orbit of the inner companion, and demonstrate that it is a plausible cause of the astrometric acceleration. This result demonstrates the importance of vetting of targets with measured astrometric acceleration for short-period stellar companions prior to conducting targeted direct imaging surveys for wide-orbit substellar companions.


Raman Investigations On Gamma Irradiated Ipp-Vgcnf Nanocomposites: The Polymer's Tale, Dorina M. Chipara, Corina Secu, Karen Lozano, Mihail Secu, Mircea Chipara Dec 2019

Raman Investigations On Gamma Irradiated Ipp-Vgcnf Nanocomposites: The Polymer's Tale, Dorina M. Chipara, Corina Secu, Karen Lozano, Mihail Secu, Mircea Chipara

Physics and Astronomy Faculty Publications and Presentations

Raman investigations on nanocomposites obtained by loading various amounts of vapor grown carbon nanofibers within an isotactic polypropylene matrix, and gamma irradiated in air, at various integral doses ranging between 0 and 27 kGy, are reported. The analysis is focused on the polymer's answers as revealed by Raman spectroscopy and investigate in detail the effect of ionizing radiation on the position of the Raman line originating from the polymer. The as-obtained data are correlated to the elastic features of the nanocomposites. A competition between gamma irradiation and loading by carbon nanofiber, resulting in the stretching of the polymeric matrix …


A Unified Binary Neutron Star Merger Magnetar Model For The Chandra X-Ray Transients Cdf-S Xt1 And Xt2, Hui Sun, Ye Li, Bin-Bin Zhang, Bing Zhang, Franz E. Bauer, Yongquan Xue, Weimin Yuan Nov 2019

A Unified Binary Neutron Star Merger Magnetar Model For The Chandra X-Ray Transients Cdf-S Xt1 And Xt2, Hui Sun, Ye Li, Bin-Bin Zhang, Bing Zhang, Franz E. Bauer, Yongquan Xue, Weimin Yuan

Physics & Astronomy Faculty Research

Two bright X-ray transients were reported from the Chandra Deep Field South (CDF-S) archival data, namely CDF-S XT1 and XT2. Whereas the nature of the former is not identified, the latter was suggested as an excellent candidate for a rapidly spinning magnetar born from a binary neutron star (BNS) merger. Here we propose a unified model to interpret both transients within the framework of the BNS merger magnetar model. According to our picture, CDF-S XT2 is observed from the "free zone" where the magnetar spindown powered X-ray emission escapes freely, whereas CDF-S XT1 originates from the "trapped zone" where the …


Tidal Destruction In A Low-Mass Galaxy Environment: The Discovery Of Tidal Tails Around Ddo 44, Jeffrey Carlin, Christopher Garling, Annika Peter, Denija Crnojević, Duncan Forbes, Jonathan Hargis, Burçin Mutlu-Pakdil, Ragadeepika Pucha, Aaron Romanowsky, David Sand, Kristine Spekkens, Jay Strader, Beth Willman Nov 2019

Tidal Destruction In A Low-Mass Galaxy Environment: The Discovery Of Tidal Tails Around Ddo 44, Jeffrey Carlin, Christopher Garling, Annika Peter, Denija Crnojević, Duncan Forbes, Jonathan Hargis, Burçin Mutlu-Pakdil, Ragadeepika Pucha, Aaron Romanowsky, David Sand, Kristine Spekkens, Jay Strader, Beth Willman

Faculty Publications

We report the discovery of a 1° (~50 kpc) long stellar tidal stream emanating from the dwarf galaxy DDO 44, a likely satellite of Local Volume galaxy NGC 2403 located ~70 kpc in projection from its companion. NGC 2403 is a roughly Large Magellanic Cloud (LMC) stellar-mass galaxy 3 Mpc away, residing at the outer limits of the M81 group. We are mapping a large region around NGC 2403 as part of our Magellanic Analogs' Dwarf Companions and Stellar Halos survey, reaching point-source depths (90% completeness) of (g, i) = (26.5, 26.2). Density maps of old, metal-poor RGB stars reveal …


A Hubble Pancet Study Of Hat-P-11b: A Cloudy Neptune With A Low Atmospheric Metallicity, Yayaati Chachan, Heather A. Knutson, Peter Gao, Tiffany Kataria, Ian Wong, Gregory W. Henry, Bjorn Benneke, Michael Zhang, Joanna Barstow, Jacob L. Bean, Thomas Mikal-Evans, Nikole K. Lewis, Megan Mansfield, Mercedes López-Morales, Nikolay Nikolov, David K. Sing, Hannah Wakeford Nov 2019

A Hubble Pancet Study Of Hat-P-11b: A Cloudy Neptune With A Low Atmospheric Metallicity, Yayaati Chachan, Heather A. Knutson, Peter Gao, Tiffany Kataria, Ian Wong, Gregory W. Henry, Bjorn Benneke, Michael Zhang, Joanna Barstow, Jacob L. Bean, Thomas Mikal-Evans, Nikole K. Lewis, Megan Mansfield, Mercedes López-Morales, Nikolay Nikolov, David K. Sing, Hannah Wakeford

Information Systems and Engineering Management Research Publications

We present the first comprehensive look at the 0.35–5 μm transmission spectrum of the warm (∼800 K) Neptune HAT-P-11b derived from 13 individual transits observed using the Hubble and Spitzer Space Telescopes. Along with the previously published molecular absorption feature in the 1.1–1.7 μm bandpass, we detect a distinct absorption feature at 1.15 μm and a weak feature at 0.95 μm, indicating the presence of water and/or methane with a combined significance of 4.4σ. We find that this planet's nearly flat optical transmission spectrum and attenuated near-infrared molecular absorption features are best matched by models incorporating a high-altitude cloud layer. …


Search For Gravitational-Wave Signals Associated With Gamma-Ray Bursts During The Second Observing Run Of Advanced Ligo And Advanced Virgo, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration Nov 2019

Search For Gravitational-Wave Signals Associated With Gamma-Ray Bursts During The Second Observing Run Of Advanced Ligo And Advanced Virgo, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration

Faculty Publications

We present the results of targeted searches for gravitational-wave transients associated with gamma-ray bursts during the second observing run of Advanced LIGO and Advanced Virgo, which took place from 2016 November to 2017 August. We have analyzed 98 gamma-ray bursts using an unmodeled search method that searches for generic transient gravitational waves and 42 with a modeled search method that targets compact-binary mergers as progenitors of short gamma-ray bursts. Both methods clearly detect the previously reported binary merger signal GW170817, with p-values of <9.38 × 10−6 (modeled) and 3.1 × 10−4 (unmodeled). We do not find any significant evidence for …


Tests Of General Relativity With The Binary Black Hole Signals From The Ligo-Virgo Catalog Gwtc-1, B. P. Abbott, S. Mukherjee Nov 2019

Tests Of General Relativity With The Binary Black Hole Signals From The Ligo-Virgo Catalog Gwtc-1, B. P. Abbott, S. Mukherjee

Physics and Astronomy Faculty Publications and Presentations

The detection of gravitational waves by Advanced LIGO and Advanced Virgo provides an opportunity to test general relativity in a regime that is inaccessible to traditional astronomical observations and laboratory tests. We present four tests of the consistency of the data with binary black hole gravitational waveforms predicted by general relativity. One test subtracts the best-fit waveform from the data and checks the consistency of the residual with detector noise. The second test checks the consistency of the low- and high-frequency parts of the observed signals. The third test checks that phenomenological deviations introduced in the waveform model (including in …


Tests Of General Relativity With The Binary Black Hole Signals From The Ligo-Virgo Catalog Gwtc-1, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration Nov 2019

Tests Of General Relativity With The Binary Black Hole Signals From The Ligo-Virgo Catalog Gwtc-1, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration

Faculty Publications

The detection of gravitational waves by Advanced LIGO and Advanced Virgo provides an opportunity to test general relativity in a regime that is inaccessible to traditional astronomical observations and laboratory tests. We present four tests of the consistency of the data with binary black hole gravitational waveforms predicted by general relativity. One test subtracts the best-fit waveform from the data and checks the consistency of the residual with detector noise. The second test checks the consistency of the low- and high-frequency parts of the observed signals. The third test checks that phenomenological deviations introduced in the waveform model (including in …


Meps Data Assimilation System, Robert W. Schunk, Larry Gardner Nov 2019

Meps Data Assimilation System, Robert W. Schunk, Larry Gardner

Browse all Datasets

For the current funding opportunity we propose to develop a master system that will enhance the user interface to the MEPS model and enable the scientific community to efficiently use the model. Furthermore, we will build and automate validation tools and improve the efficiency and robustness of the MEPS ensemble averaging scheme. Finally, we will explore the nest step toward a major advancement in MEPS b significantly improving the spatial resolution of one of the data assimilation models to explore meso- and small-scale features.


Morphological Signatures Induced By Dust Back Reactions In Discs With An Embedded Planet, Chao-Chin Yang, Zhaohuan Zhu Nov 2019

Morphological Signatures Induced By Dust Back Reactions In Discs With An Embedded Planet, Chao-Chin Yang, Zhaohuan Zhu

Physics & Astronomy Faculty Research

Recent observations have revealed a gallery of substructures in the dust component of nearby protoplanetary discs, including rings, gaps, spiral arms, and lopsided concentrations. One interpretation of these substructures is the existence of embedded planets. Not until recently, however, most of the modelling effort to interpret these observations ignored the dust back reaction to the gas. In this work, we conduct local-shearing-sheet simulations for an isothermal, inviscid, non-self-gravitating, razor-thin dusty disc with a planet on a fixed circular orbit. We systematically examine the parameter space spanned by planet mass (0.1Mth ≤ Mp ≤ 1Mth, where Mth is the thermal mass), …


Wasp-52b. The Effect Of Star-Spot Correction On Atmospheric Retrievals, Giovanni Bruno, Nikole K. Lewis, Munazza K. Alam, Mercedes López-Morales, Joanna K. Barstow, Hannah R. Wakeford, David K. Sing, Gregory W. Henry, Gilda E. Ballester, Vincent Bourrier, Lars A. Buchhave, Ofer Cohen, Thomas Mikal-Evans, Antonio García Muñoz, Panayotis Lavvas, Jorge Sanz-Forcada Nov 2019

Wasp-52b. The Effect Of Star-Spot Correction On Atmospheric Retrievals, Giovanni Bruno, Nikole K. Lewis, Munazza K. Alam, Mercedes López-Morales, Joanna K. Barstow, Hannah R. Wakeford, David K. Sing, Gregory W. Henry, Gilda E. Ballester, Vincent Bourrier, Lars A. Buchhave, Ofer Cohen, Thomas Mikal-Evans, Antonio García Muñoz, Panayotis Lavvas, Jorge Sanz-Forcada

Information Systems and Engineering Management Research Publications

We perform atmospheric retrievals on the full optical to infrared (0.3−5μm⁠) transmission spectrum of the inflated hot Jupiter WASP-52b by combining HST/STIS, WFC3 IR, and Spitzer/IRAC observations. As WASP-52 is an active star that shows both out-of-transit photometric variability and star-spot crossings during transits, we account for the contribution of non-occulted active regions in the retrieval. We recover a 0.1–10× solar atmospheric composition, in agreement with core accretion predictions for giant planets, and no significant contribution of aerosols. We also obtain a star-spots, a measure which is likely affected by the models used to fit instrumental effects in …


Graded Quivers, Generalized Dimer Models And Toric Geometry, Sebastián Franco, Azeem Hasan Nov 2019

Graded Quivers, Generalized Dimer Models And Toric Geometry, Sebastián Franco, Azeem Hasan

Publications and Research

The open string sector of the topological B-model on CY (m+2)-folds is described by m-graded quivers with superpotentials. This correspondence extends to general m the well known connection between CY (m+2)-folds and gauge theories on the world-volume of D(5-2m)-branes for m = 0, ..., 3. We introduce m-dimers, which fully encode the m-graded quivers and their superpotentials, in the case in which the CY (m+2)-folds are toric. Generalizing the well known m = 1,2 cases, m-dimers significantly simplify the connection between geometry and m-graded quivers. A key …


Realistic Sensitivity Curves For Pulsar Timing Arrays, ‪Jeffrey S. Hazboun, Joseph D. Romano, Tristan L. Smith Nov 2019

Realistic Sensitivity Curves For Pulsar Timing Arrays, ‪Jeffrey S. Hazboun, Joseph D. Romano, Tristan L. Smith

Physics and Astronomy Faculty Publications and Presentations

We construct realistic sensitivity curves for pulsar timing array searches for gravitational waves, incorporating both red and white noise contributions to individual pulsar noise spectra, and the effect of fitting to a pulsar timing model. We demonstrate the method on both simulated pulsars and a realistic array consisting of a subset of NANOGrav pulsars used in recent analyses. A comparison between the results presented here and measured upper limit curves from actual analyses shows agreement to tens of percent. The resulting sensitivity curves can be used to assess the detectability of predicted gravitational-wave signals in the nanohertz frequency band in …


Evolution Of A Relativistic Electron Beam For Tracing Magnetospheric Field Lines, Andrew T. Powis, Peter Porazik, Michael Greklek-Mckeon, Kailas Amin, David Shaw, Igor D. Kaganovich, Jay R. Johnson, Ennio Sanchez Nov 2019

Evolution Of A Relativistic Electron Beam For Tracing Magnetospheric Field Lines, Andrew T. Powis, Peter Porazik, Michael Greklek-Mckeon, Kailas Amin, David Shaw, Igor D. Kaganovich, Jay R. Johnson, Ennio Sanchez

Faculty Publications

Tracing magnetic field-lines of the Earth's magnetosphere using beams of relativistic electrons will open up new insights into space weather and magnetospheric physics. Analytic models and a single-particle-motion code were used to explore the dynamics of an electron beam emitted from an orbiting satellite and propagating until impact with the Earth. The impact location of the beam on the upper atmosphere is strongly influenced by magnetospheric conditions, shifting up to several degrees in latitude between different phases of a simulated storm. The beam density cross-section evolves due to cyclotron motion of the beam centroid and oscillations of the beam envelope. …


Secondary Infall In The Seyfert's Sextet: A Plausible Way Out Of The Short Crossing Time Paradox, Omar López-Cruz, Héctor Javier Ibarra-Medel, Sebastián F. Sánchez, Mark Birkinshaw, Christopher Añorve, Jorge K. Barrera-Ballesteros, Jesús Falcon-Barroso, Wayne A. Barkhouse, Juan P. Torres-Papaqui Nov 2019

Secondary Infall In The Seyfert's Sextet: A Plausible Way Out Of The Short Crossing Time Paradox, Omar López-Cruz, Héctor Javier Ibarra-Medel, Sebastián F. Sánchez, Mark Birkinshaw, Christopher Añorve, Jorge K. Barrera-Ballesteros, Jesús Falcon-Barroso, Wayne A. Barkhouse, Juan P. Torres-Papaqui

Physics Faculty Publications

We used integral field spectroscopy from CALIFA DR3 and multiwavelength publicly available data to investigate the star formation histories of galaxies in the Seyfert's Sextet (SS; HCG 79). The galaxies H79a, H79b, H79c, and H79f have low star formation rates despite showing strong signs of interaction. By exploring their individual specific star formation histories, we identified three earlier episodes of strong star formation common to these four galaxies. We use the last two episodes as markers of the epochs when the galaxies were crossing. We suggest that after the first turnaround, initially gas-rich galaxies crossed for the first time, consuming …


Spatially Resolved Stellar Kinematics Of The Ultra-Diffuse Galaxy Dragonfly 44. Ii. Constraints On Fuzzy Dark Matter, Asher Wasserman, Pieter Van Dokkum, Aaron Romanowsky, Jean Brodie, Shany Danieli, Duncan Forbes, Roberto Abraham, Christopher Martin, Matt Matuszewski, Alexa Villaume, John Tamanas, Stefano Profumo Nov 2019

Spatially Resolved Stellar Kinematics Of The Ultra-Diffuse Galaxy Dragonfly 44. Ii. Constraints On Fuzzy Dark Matter, Asher Wasserman, Pieter Van Dokkum, Aaron Romanowsky, Jean Brodie, Shany Danieli, Duncan Forbes, Roberto Abraham, Christopher Martin, Matt Matuszewski, Alexa Villaume, John Tamanas, Stefano Profumo

Faculty Publications

Given the absence of directly detected dark matter (DM) as weakly interacting massive particles, there is strong interest in the possibility that DM is an ultralight scalar field, here denoted as "fuzzy" DM. Ultra-diffuse galaxies, with the sizes of giant galaxies and the luminosities of dwarf galaxies, have a wide range of DM halo masses, thus providing new opportunities for exploring the connections between galaxies and their DM halos. Following up on new integral field unit spectroscopic observations and dynamics modeling of the DM-dominated ultra-diffuse galaxy Dragonfly 44 in the outskirts of the Coma Cluster, we present models of fuzzy …


Detection And Characterisation Of 54 Massive Companions With The Sophie Spectrograph: Seven New Brown Dwarfs And Constraints On The Brown Dwarf Desert, ‪Flavien Kiefer, Guillaume Hébrard, Johannes Sahlmann, Sérgio G. Sousa, Thierry Forveille, Nuno Santos, Michel Mayor, Magali Deleuil, Paul Anthony Wilson, Shweta Dalal, Rodrigo F. Díaz, Gregory W. Henry, Janis Hagelberg, Melissa J. Hobson, Olivier Demangeon, Vincent Bourrier, Xavier Delfosse, Luc Arnold, Nicola Astudillo-Defru, Jean-Luc Beuzit, Isabelle Boisse, Xavier Bonfils, Simon Borgniet, François Bouchy, B. Courcol, David Ehrenreich, Nathan Hara, Anne-Marie Lagrange, Christophe Lovis, Guillaume Montagnier, C. Moutou, Francesco Pepe, Christian Perrier, Javiera Rey, Alexandre Santerne, Damien Ségransan, Stephane Udry, Alfred Vidal-Madjar Nov 2019

Detection And Characterisation Of 54 Massive Companions With The Sophie Spectrograph: Seven New Brown Dwarfs And Constraints On The Brown Dwarf Desert, ‪Flavien Kiefer, Guillaume Hébrard, Johannes Sahlmann, Sérgio G. Sousa, Thierry Forveille, Nuno Santos, Michel Mayor, Magali Deleuil, Paul Anthony Wilson, Shweta Dalal, Rodrigo F. Díaz, Gregory W. Henry, Janis Hagelberg, Melissa J. Hobson, Olivier Demangeon, Vincent Bourrier, Xavier Delfosse, Luc Arnold, Nicola Astudillo-Defru, Jean-Luc Beuzit, Isabelle Boisse, Xavier Bonfils, Simon Borgniet, François Bouchy, B. Courcol, David Ehrenreich, Nathan Hara, Anne-Marie Lagrange, Christophe Lovis, Guillaume Montagnier, C. Moutou, Francesco Pepe, Christian Perrier, Javiera Rey, Alexandre Santerne, Damien Ségransan, Stephane Udry, Alfred Vidal-Madjar

Information Systems and Engineering Management Research Publications

Context. Brown dwarfs (BD) are substellar objects intermediate between planets and stars with masses of ~13–80 MJ. While isolated BDs are most likely produced by gravitational collapse in molecular clouds down to masses of a few MJ, a non-negligible fraction of low-mass companions might be formed through the planet-formation channel in protoplanetary discs. The upper mass limit of objects formed within discs is still observationally unknown, the main reason being the strong dearth of BD companions at orbital periods shorter than 10 yr, also known as the BD desert.

Aims. To address this question, we aim …


Milky Way Morphology, Laurence A. Marschall Nov 2019

Milky Way Morphology, Laurence A. Marschall

Physics and Astronomy Faculty Publications

From our limited perspective—living on a planet that orbits one of several hundred billion stars inside the Milky Way—the detailed structure of our home galaxy is difficult to determine. It has long been recognized by astronomers as a typical spiral galaxy, one of countless flattened pinwheels of stars seen throughout the universe. By mapping the distances to more than 2,400 stars, scientists have now created, with unprecedented precision, a three-dimensional map that shows the Milky Way has a twisted shape. [excerpt]


Dark Matter And No Dark Matter: On The Halo Mass Of Ngc 1052, Duncan Forbes, Adebusola Alabi, Jean Brodie, Aaron Romanowsky Nov 2019

Dark Matter And No Dark Matter: On The Halo Mass Of Ngc 1052, Duncan Forbes, Adebusola Alabi, Jean Brodie, Aaron Romanowsky

Faculty Publications

The NGC 1052 group, and in particular the discovery of two ultra-diffuse galaxies with very low internal velocity dispersions, has been the subject of much attention recently. Here we present radial velocities for a sample of 77 globular clusters associated with NGC 1052 obtained on the Keck telescope. Their mean velocity and velocity dispersion are consistent with that of the host galaxy. Using a simple tracer mass estimator, we infer the enclosed dynamical mass and dark matter fraction of NGC 1052. Extrapolating our measurements with a Navarro–Frenk–White (NFW) mass profile we infer a total halo mass of 6.2(±0.2) × 1012 …


Toi-150b And Toi-163b: Two Transiting Hot Jupiters, One Eccentric And One Inflated, Revealed By Tess Near And At The Edge Of The Jwst Cvz, D. Kossakowski, N. Espinoza, R. Brahm, A. Jordán, T. Henning, F. Rojas, M. Kürster, P. Sarkis, M. Schlecker, F. J. Pozuelos, K. Barkaoui, E. Jehin, M. Gillon, E. Matthews, E. P. Horch, D. R. Ciardi, I. J. M. Crossfield, E. Gonzales, S. B. Howell, R. Matson, J. Schlieder, J. Jenkins, G. Ricker, S. Seager, J. N. Winn, J. Li, M. E. Rose, J. C. Smith, S. Dynes, E. Morgan, J. N. Villasenor, D. Charbonneau, T. Jaffe, L. Yu, G. Bakos, W. Bhatti, F. Bouchy, K. A. Collins, K. I. Collins, Z. Csubry, P. Evans, Eric L.N. Jensen, C. Lovis, M. Marmier, L. D. Nielsen, D. Osip, F. Pepe, H. M. Relles, D. Ségransan, A. Shporer, C. Stockdale, V. Suc, O. Turner, S. Udry Nov 2019

Toi-150b And Toi-163b: Two Transiting Hot Jupiters, One Eccentric And One Inflated, Revealed By Tess Near And At The Edge Of The Jwst Cvz, D. Kossakowski, N. Espinoza, R. Brahm, A. Jordán, T. Henning, F. Rojas, M. Kürster, P. Sarkis, M. Schlecker, F. J. Pozuelos, K. Barkaoui, E. Jehin, M. Gillon, E. Matthews, E. P. Horch, D. R. Ciardi, I. J. M. Crossfield, E. Gonzales, S. B. Howell, R. Matson, J. Schlieder, J. Jenkins, G. Ricker, S. Seager, J. N. Winn, J. Li, M. E. Rose, J. C. Smith, S. Dynes, E. Morgan, J. N. Villasenor, D. Charbonneau, T. Jaffe, L. Yu, G. Bakos, W. Bhatti, F. Bouchy, K. A. Collins, K. I. Collins, Z. Csubry, P. Evans, Eric L.N. Jensen, C. Lovis, M. Marmier, L. D. Nielsen, D. Osip, F. Pepe, H. M. Relles, D. Ségransan, A. Shporer, C. Stockdale, V. Suc, O. Turner, S. Udry

Physics & Astronomy Faculty Works

We present the discovery of TYC9191-519-1b (TOI-150b, TIC 271893367) and HD271181b (TOI-163b, TIC 179317684), two hot Jupiters initially detected using 30-min cadence Transiting Exoplanet Survey Satellite (TESS) photometry from Sector 1 and thoroughly characterized through follow-up photometry (CHAT, Hazelwood, LCO/CTIO, El Sauce, TRAPPIST-S), high-resolution spectroscopy (FEROS, CORALIE), and speckle imaging (Gemini/DSSI), confirming the planetary nature of the two signals. A simultaneous joint fit of photometry and radial velocity using a new fitting package juliet reveals that TOI-150b is a 1.254±0.016 RJ⁠, massive (⁠2.61+0.19−0.12 MJ⁠) hot Jupiter in a 5.857-d orbit, while TOI-163b is an inflated (⁠RP = 1.478+0.022−0.029RJ⁠, MP = …


Effect Of Galaxy Mergers On Star-Formation Rates, W. J. Pearson, L. Wang, M. Alpaslan, I. Baldry, M. Bilicki, M. J.I. Brown, M. W. Grootes, Benne W. Holwerda, T. D. Kitching, S. Kruk, F. F.S. Van Der Tak Nov 2019

Effect Of Galaxy Mergers On Star-Formation Rates, W. J. Pearson, L. Wang, M. Alpaslan, I. Baldry, M. Bilicki, M. J.I. Brown, M. W. Grootes, Benne W. Holwerda, T. D. Kitching, S. Kruk, F. F.S. Van Der Tak

Faculty Scholarship

Context. Galaxy mergers and interactions are an integral part of our basic understanding of how galaxies grow and evolve over time. However, the effect that galaxy mergers have on star-formation rates (SFRs) is contested, with observations of galaxy mergers showing reduced, enhanced, and highly enhanced star formation. Aims. We aim to determine the effect of galaxy mergers on the SFR of galaxies using statistically large samples of galaxies, totalling over 200 000, which is over a large redshift range from 0.0 to 4.0. Methods. We trained and used convolutional neural networks to create binary merger identifications (merger or non-merger) in …


Default Parallels: The Science Potential Of Jwst Parallel Observations During Tso Primary Observations, Benne W. Holwerda, Jonathan Fraine, Nelly Mouawad, Joanna S. Bridge Nov 2019

Default Parallels: The Science Potential Of Jwst Parallel Observations During Tso Primary Observations, Benne W. Holwerda, Jonathan Fraine, Nelly Mouawad, Joanna S. Bridge

Faculty Scholarship

The James Webb Space Telescope (JWST) will observe several stars for long cumulative durations while pursuing exoplanets as primary science targets for both Guaranteed Time Observations (GTO) and very likely General Observer (GO) programs. Here we argue in favor of an automatic default parallel program to observe, e.g., using the F200W/F277W filters or grism of NIRCAM/NIRISS in order to find high redshift (z (Formula Presented) 10) galaxies, cool red/brown dwarf substellar objects, solar system objects, and observations of serendipitous planetary transits. We argue here the need for automated exploratory astrophysical observations with unused JWST instruments during these long-duration exoplanet observations. …


Near-Resonance In A System Of Sub-Neptunes From Tess, S. N. Quinn, J. C. Becker, J. E. Rodriguez, S. Hadden, C. X. Huang, T. D. Morton, F. C. Adams, D. Armstrong, J. D. Eastman, J. Homer, S. R. Kane, J. J. Lissauer, J. D. Twicken, A. Vanderburg, R. Wittenmyer, G. R. Ricker, R. K. Vanderspek, D. W. Latham, S. Seager, J. N. Winn, J. M. Jenkins, E. Agol, K. Barkaoui, C. A. Beichman, F. Bouchy, L. G. Bouma, A. Burdanov, J. Campbell, R. Carlino, S. M. Cartwright, D. Charbonneau, J. L. Christiansen, D. Ciardi, K. A. Collins, K. I. Collins, D. M. Conti, I. J. M. Crossfield, T. Daylan, J. Dittmann, J. Doty, D. Dragomir, E. Ducrot, M. Gillon, A. Glidden, R. F. Goeke, E. J. Gonzales, K. G. Hełminiak, E. P. Horch, S. B. Howell, E. Jehin, Eric L.N. Jensen, J. F. Kielkopf, M. H. Kristiansen, N. Law, A. W. Mann, M. Marmier, R. A. Matson, E. Matthews, T. Mazeh, M. Mori, F. Murgas, C. Murray, N. Narita, L. D. Nielsen, G. Ottoni, E. Palle, R. Pawłaszek, F. Pepe, J. Pitogo De Leon, F. J. Pozuelos, H. M. Relles, J. E. Schlieder, D. Sebastian, D. Ségransan, A. Shporer, K. G. Stassun, M. Tamura, S. Udry, I. Waite, J. G. Winters, C. Ziegler Nov 2019

Near-Resonance In A System Of Sub-Neptunes From Tess, S. N. Quinn, J. C. Becker, J. E. Rodriguez, S. Hadden, C. X. Huang, T. D. Morton, F. C. Adams, D. Armstrong, J. D. Eastman, J. Homer, S. R. Kane, J. J. Lissauer, J. D. Twicken, A. Vanderburg, R. Wittenmyer, G. R. Ricker, R. K. Vanderspek, D. W. Latham, S. Seager, J. N. Winn, J. M. Jenkins, E. Agol, K. Barkaoui, C. A. Beichman, F. Bouchy, L. G. Bouma, A. Burdanov, J. Campbell, R. Carlino, S. M. Cartwright, D. Charbonneau, J. L. Christiansen, D. Ciardi, K. A. Collins, K. I. Collins, D. M. Conti, I. J. M. Crossfield, T. Daylan, J. Dittmann, J. Doty, D. Dragomir, E. Ducrot, M. Gillon, A. Glidden, R. F. Goeke, E. J. Gonzales, K. G. Hełminiak, E. P. Horch, S. B. Howell, E. Jehin, Eric L.N. Jensen, J. F. Kielkopf, M. H. Kristiansen, N. Law, A. W. Mann, M. Marmier, R. A. Matson, E. Matthews, T. Mazeh, M. Mori, F. Murgas, C. Murray, N. Narita, L. D. Nielsen, G. Ottoni, E. Palle, R. Pawłaszek, F. Pepe, J. Pitogo De Leon, F. J. Pozuelos, H. M. Relles, J. E. Schlieder, D. Sebastian, D. Ségransan, A. Shporer, K. G. Stassun, M. Tamura, S. Udry, I. Waite, J. G. Winters, C. Ziegler

Physics & Astronomy Faculty Works

We report the Transiting Exoplanet Survey Satellite detection of a multi-planet system orbiting the V = 10.9 K0 dwarf TOI-125. We find evidence for up to five planets, with varying confidence. Three transit signals with high signal-to-noise ratio correspond to sub-Neptune-sized planets (2.76, 2.79, and 2.94 R), and we statistically validate the planetary nature of the two inner planets (Pb = 4.65 days, Pc = 9.15 days). With only two transits observed, we report the outer object (P.03 = 19.98 days) as a planet candidate with high signal-to-noise ratio. We also detect a candidate transiting …