Astrophysics and Astronomy Commons^™

The Allowed Parameter Space Of A Long-Lived Neutron Star As The Merger Remnant Of Gw170817, Shunke Ai, He Gao, Zi-Gao Dai, Xue-Feng Wu, Ang Li, Bing Zhang, Mu-Zi Li

Physics & Astronomy Faculty Research

Due to the limited sensitivity of the current gravitational wave (GW) detectors, the central remnant of the binary neutron star (NS) merger associated with GW170817 remains an open question. In view of the relatively large total mass, it is generally proposed that the merger of GW170817 would lead to a short-lived hypermassive NS or directly produce a black hole (BH). There is no clear evidence to support or rule out a long-lived NS as the merger remnant. Here, we utilize the GW and electromagnetic (EM) signals to comprehensively investigate the parameter space that allows a long-lived NS to survive as …

On The Radio Detectability Of Circumplanetary Discs, Zhaohuan Zhu, Sean M. Andrews, Andrea Isella

Physics & Astronomy Faculty Research

Discs around young planets, so-called circumplanetary discs (CPDs), are essential for planet growth, satellite formation, and planet detection. We study the millimetre and centimetre emission from accreting CPDs by using the simple α disc model. We find that it is easier to detect CPDs at shorter radio wavelengths (e.g. λ ≲ 1 mm). For example, if the system is 140 pc away from us, deep observations (e.g. 5 h) at ALMA Band 7 (0.87 mm) are sensitive to as small as 0.03 lunar mass of dust in CPDs. If the CPD is around a Jupiter mass planet 20 au away …

Galaxy And Mass Assembly (Gama): Gas Fuelling Of Spiral Galaxies In The Local Universe Ii. - Direct Measurement Of The Dependencies On Redshift And Host Halo Mass Of Stellar Mass Growth In Central Disc Galaxies, M. W. Grootes, A. Dvornik, R. J. Laureijs, R. J. Tuffs, C. C. Popescu, A. S.G. Robotham, J. Liske, M. J.I. Brown, Benne W. Holwerda, L. Wang

Faculty and Staff Scholarship

We present a detailed analysis of the specific star formation rate-stellar mass (sSFR-M*) of z ≤ 0.13 disc central galaxies using a morphologically selected mass-complete sample (M* ≥ 109.5M⊙). Considering samples of grouped and ungrouped galaxies, we find the sSFR-M* relations of disc-dominated central galaxies to have no detectable dependence on host dark-matter halo (DMH) mass, even where weak-lensing measurements indicate a difference in halo mass of a factor ≳ 5.We further detect a gradual evolution of the sSFR-M* relation of non-grouped (field) central disc galaxies with redshift, even over a Δz ≈ 0.04 (≈5 × 108 yr) interval, while …

Automation And Enhancements To The Erau Oscom System Space Situational Awareness, Sergei Bilardi, Patrick Rupp, Yevgeniy Lischuk, Joseph Stroup

Beyond: Undergraduate Research Journal

OSCOM, Optical tracking and Spectral characterization of CubeSats for Operational Missions, is a system developed at Embry-Riddle Aeronautical University to produce time-resolved photometry of small satellites using commercial-off-the-shelf hardware. OSCOM has been able to observe resident space objects (RSOs) as small as CubeSats using a Celestron 11” RASA and a CMOS machine vision camera from Allied Vision. By obtaining photometric measurements of satellites, a light curve can be constructed and used to help determine satellite characteristics such as spin rate, satellite state, and even satellite attitude. To enhance the OSCOM system’s ability to observe small satellites, there is ongoing development …

Multiple Stellar Flybys Sculpting The Circumstellar Architecture In Rw Aurigae, J. E. Rodriguez, R. Loomis, S. Cabrit, T. H. Haworth, S. Facchini, C. Dougados, R. A. Booth, Eric L.N. Jensen, C. J. Clarke, K. G. Stassun, W. R. F. Dent, J. Pety

Physics & Astronomy Faculty Works

We present high-resolution ALMA Band 6 and 7 observations of the tidally disrupted protoplanetary disks of the RW Aurigae binary. Our observations reveal tidal streams in addition to the previously observed tidal arm around RW Aur A. The observed configuration of tidal streams surrounding RW Aur A and B is incompatible with a single star–disk tidal encounter, suggesting that the RW Aurigae system has undergone multiple flyby interactions. We also resolve the circumstellar disks around RW Aur A and B, with CO radii of 58 au and 38 au consistent with tidal truncation, and 2.5 times smaller dust emission radii. …

Grb 120729a: External Shock Origin For Both The Prompt Gamma-Ray Emission And Afterglow, Li-Ye Huang, Xiang-Gao Wang, Weikang Zheng, En-Wei Liang, Da-Bin Lin, Shi-Qing Zhong, Hai-Ming Zhang, Xiao-Li Huang, Alexi V. Filippenko, Bing Zhang

Physics & Astronomy Faculty Research

Gamma-ray burst (GRB) 120729A was detected by Swift/BAT and Fermi/GBM, and then rapidly observed by Swift/XRT, Swift/UVOT, and ground-based telescopes. It had a single long and smooth \gamma-ray emission pulse, which extends continuously to the X-rays. We report Lick/KAIT observations of the source, and make temporal and spectral joint fits of the multiwavelength light curves of GRB 120729A. It exhibits achromatic light-curve behavior, consistent with the predictions of the external shock model. The light curves are decomposed into four typical phases: onset bump (Phase I), normal decay (Phase II), shallow decay (Phase III), and post-jet break (Phase IV). The spectral …

Gamma-Ray Burst Jet Breaks Revisited, Xiang-Gao Wang, Bing Zhang, En-Wei Liang, Rui-Jing Liang, Da-Bin Lin, Jing Li, Long Li

Physics & Astronomy Faculty Research

Gamma-ray Burst (GRB) collimation has been inferred with the observations of achromatic steepening in GRB light curves, known as jet breaks. Identifying a jet break from a GRB afterglow light curve allows a measurement of the jet opening angle and true energetics of GRBs. In this paper, we re-investigate this problem using a large sample of GRBs that have an optical jet break that is consistent with being achromatic in the X-ray band. Our sample includes 99 GRBs from 1997 February to 2015 March that have optical and, for Swift GRBs, X-ray light curves that are consistent with the jet …

Controlling The Hydrophilicity And Cohesion During Deposition Of Highly Oriented Type I Collagen Films: An Approach For Biomedical Applications, Karina Ambrock, Bernd Grohe, Silvia Mittler

Physics and Astronomy Publications

Using the Langmuir-Blodgett (LB) technology we have pioneered a straightforward and low-cost approach to fabricate highly oriented collagen in thin film format (thickness: ~20 nm, surface areas: 2.5 x ~6.0 cm). An important factor for the use of these films is their cohesion under various conditions. Film formation was studied by coating hydrophilic or hydrophobic glass substrates. The fresh or aged (2 ½ years, -18°C.) collagen solutions used for this purpose either contained collagen network-stabilizing agents (n-propanol or phosphate ions) or were prepared without these stabilizers. Film formation on the air/water interface was analyzed by pressure-area isotherms. Maximum surface pressures …

Gpi Spectra Of Hr 8799 C, D, And E From 1.5 To 2.4 Μm With Klip Forward Modeling, Alexandra Z. Greenbaum, Laurent Pueyo, Jean Baptiste Ruffio, Jason J. Wang, Robert J.De Rosa, Jonathan Aguilar, Julien Rameau, Travis Barman, Christian Marois, Mark S. Marley, Quinn Konopacky, Abhijith Rajan, Bruce Macintosh, Megan Ansdell, Pauline Arriaga, Vanessa P. Bailey, Joanna Bulger, Adam S. Burrows, Jeffrey Chilcote, Tara Cotten, Rene Doyon, Gaspard Duchêne, Michael P. Fitzgerald, Katherine B. Follette, Benjamin Gerard, Stephen J. Goodsell, James R. Graham, Pascale Hibon, Li Wei Hung, Patrick Ingraham, Paul Kalas, James E. Larkin, Kimberly Ward-Duong, Et Al

Astronomy: Faculty Publications

We explore KLIP forward modeling spectral extraction on Gemini Planet Imager coronagraphic data of HR 8799, using PyKLIP, and show algorithm stability with varying KLIP parameters. We report new and re-reduced spectrophotometry of HR 8799 c, d, and e in the H and K bands. We discuss a strategy for choosing optimal KLIP PSF subtraction parameters by injecting simulated sources and recovering them over a range of parameters. The K1/K2 spectra for HR 8799 c and d are similar to previously published results from the same data set. We also present a K-band spectrum of HR 8799 e for the …

Orbital Characteristics Of The Subdwarf-B And F V Star Binary Ec 20117-4014 (=V4640 Sgr), Tomomi Otani, T. D. Oswalt, A. E. Lynas-Gray, D. Kilkenny, C. Koen, M. Amaral, R. Jordan

Aerospace, Physics, and Space Science Faculty Publications

Among the competing evolution theories for subdwarf-B (sdB) stars is the binary evolution scenario. EC 20117- 4014 (=V4640 Sgr) is a spectroscopic binary system consisting of a pulsating sdB star and a late F main-sequence companion; however, the period and the orbit semimajor axes have not been precisely determined. This paper presents orbital characteristics of the EC 20117-4014 binary system using 20 years of photometric data. Periodic observed minus calculated (O–C) variations were detected in the two highest-amplitude pulsations identified in the EC 20117-4014 power spectrum, indicating the binary system’s precise orbital period (P = 792.3 days) and the light-travel-time …

Effects Of Coronal Magnetic Field Structures On The Transport Of Solar Energetic Particles, Lulu Zhao, Ming Zhang

Aerospace, Physics, and Space Science Faculty Publications

This Letter presents a model calculation of solar energetic particle (SEP) transport to test the sensitivity of the distribution of escaped SEPs in interplanetary space and dependence upon the details of the magnetic field structure in the corona. It is applied to a circumsolar event on 2011 November 3, in which SEPs are observed promptly after the solar event eruption by three spacecraft (the twin Solar TErrestrial RElations Observatories (STEREO-A and STEREO-B) and ACE) separated by more than 100° in longitude from each other. The corona magnetic field reconstructed from photosphseric field measurements using the PFSS method changes substantially before …

Anatomy Of The Ρ Resonance From Lattice Qcd At The Physical Point, Wei Sun, Andrei Alexandru, Ying Chen, Terrence Draper, Zhaofeng Liu, Yi-Bo Yang, Χqcd Collaboration

Physics and Astronomy Faculty Publications

We propose a strategy to access the qq component of the ρ resonance in lattice QCD.

For the remainder of the abstract, please download this article or visit https://doi.org/10.1088/1674-1137/42/6/063102.

Spectroscopic Constants And Line Positions For Tio Singlet States, Dror M. Bittner, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

consistent set of spectroscopic constants for the a¹Δ,d¹Σ⁺,b¹Π,c¹Φ, and f¹Δ states of ⁴⁸Ti¹⁶O has been determined from analysis of the b¹Π–a¹Δ,b¹Π–d¹Σ⁺,c¹Φ–a¹Δ, and f¹Δ–a¹Δ systems. Three Fourier transform emission spectra have been used for the analysis. New bands of the b¹Π–a¹Δ and c¹Φ–a¹Δ systems have been fitted. The first analysis of the c¹Φ–a¹Δ system using Fourier …

Charge Transfer Dynamical Processes At Graphene-Transition Metal Oxides/Electrolyte Interface For Energy Storage: Insights From In-Situ Raman Spectroelectrochemistry, S. Gupta, S. B. Carrizosa, J. Jasinski, Nicholas Dimakis

Physics & Astronomy Faculty Publications

Hybrids consisting of supercapacitive functionalized graphene (graphene oxide; GO reduced graphene oxide; rGO multilayer graphene; MLG, electrochemically reduced GO; ErGO) and three-dimensional graphene scaffold (rGO HT ; hydrothermally prepared) decorated with cobalt nanoparticles (CoNP), nanostructured cobalt (CoO and Co 3 O 4 ) and manganese (MnO 2 ) oxide polymorphs, assembled electrochemically facilitate chemically bridged interfaces with tunable properties. Since Raman spectroscopy can capture variations in structural and chemical bonding, Raman spectro-electrochemistry in operando i.e. under electrochemical environment with applied bias is employed to 1) probe graphene/metal bonding and dynamic processes, 2) monitor the spectral changes with successive redox interfacial …

Novel Topological Effects In Dense Qcd In A Magnetic Field, Efrain J. Ferrer, Vivian De La Incera

Physics & Astronomy Faculty Publications

We study the electromagnetic properties of dense QCD in the so-called Magnetic Dual Chiral Density Wave phase. This inhomogeneous phase exhibits a nontrivial topology that comes from the fermion sector due to the asymmetry of the lowest Landau level modes. The nontrivial topology manifests in the electromagnetic effective action via a chiral anomaly term θ F μ ν ˜ F μ ν , with a dynamic axion field θ given by the phase of the Dual Chiral Density Wave condensate. The coupling of the axion with the electromagnetic field leads to several macroscopic effects that include, among others, an anomalous, …

The Green Bank North Celestial Cap Pulsar Survey. Iii. 45 New Pulsar Timing Solutions, Ryan S. Lynch, Joseph K. Swiggum, Louis Percy Dartez, David Day, Anthony J. Ford, Jesus Hinojosa, Fredrick A. Jenet, Sean Leake, Grady Lunsford, Alberto Mata

Physics & Astronomy Faculty Publications

We provide timing solutions for 45 radio pulsars discovered by the Robert C. Byrd Green Bank Telescope. These pulsars were found in the Green Bank North Celestial Cap pulsar survey, an all-GBT-sky survey being carried out at a frequency of 350 MHz. We include pulsar timing data from the Green Bank Telescope and Low Frequency Array. Our sample includes five fully recycled millisecond pulsars (MSPs, three of which are in a binary system), a new relativistic double neutron star system, an intermediate-mass binary pulsar, a mode-changing pulsar, a 138 ms pulsar with a very low magnetic field, and several nulling …

Contribution Of Hi-Bearing Ultra-Diffuse Galaxies To The Cosmic Number Density Of Galaxies, M. Jones, E. Papastergis, V. Pandya, L. Leisman, Aaron J. Romanowsky, L. Yung, R. Somerville, E. Adams

Faculty Publications

We estimate the cosmic number density of the recently identified class of HI-bearing ultra-diffuse sources (HUDs) based on the completeness limits of the ALFALFA survey. These objects have HI masses approximately in the range 8.5 < logMHI∕M⊙ < 9.5, average r-band surface brightnesses fainter than 24 mag arcsec−2, half-light radii greater than 1.5 kpc, and are separated from neighbours by at least 350 kpc. In this work we demonstrate that they contribute at most ~6% of the population of HI-bearing dwarfs detected by ALFALFA (with similar HI masses), have a total cosmic number density of (1.5 ± 0.6) × 10−3 …

The Sluggs Survey: A Comparison Of Total-Mass Profiles Of Early-Type Galaxies From Observations And Cosmological Simulations, To ∼4 Effective Radii, Sabine Bellstedt, Duncan Forbes, Aaron Romanowsky, Rhea-Silvia Remus, Adam Stevens, Jean Brodie, Adriano Poci, Richard Mcdermid, Adebusola Alabi, Leonie Chevalier, Caitlin Adams, Anna Ferré-Mateu, Asher Wasserman, Viraj Pandya

Faculty Publications

We apply the Jeans Anisotropic Multi-Gaussian Expansion dynamical modelling method to SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey data of early-type galaxies in the stellar mass range 1010 < M*/M⊙ < 1011.6 that cover a large radial range of 0.1–4.0 effective radii. We combine SLUGGS and ATLAS3D data sets to model the total-mass profiles of a sample of 21 fast-rotator galaxies, utilizing a hyperparameter method to combine the two independent data sets. The total-mass density profile slope values derived for these galaxies are consistent with those measured in the inner regions of galaxies by other studies. Furthermore, the total-mass density slopes (γtot) appear to be universal over this broad stellar mass range, with an average value of γtot =  −2.24 ±  0.05 , i.e. slightly steeper than isothermal. We compare our results to model galaxies from the Magneticum and EAGLE cosmological hydrodynamic simulations, in order to probe the mechanisms that are responsible for varying total-mass density profile slopes. The simulated-galaxy slopes are shallower than the observed values by ∼0.3–0.5, indicating that the physical processes shaping the mass distributions of galaxies in cosmological simulations are still incomplete. For galaxies with M* > 1010.7 M⊙ in the Magneticum simulations, we identify a significant anticorrelation between total-mass density profile slopes and the fraction of stellar mass formed ex situ (i.e. accreted), whereas this anticorrelation is weaker for lower stellar masses, implying that the measured total-mass density slopes for low-mass galaxies are less likely to be determined by merger activity.

Orbital Characteristics Of The Subdwarf-B And F V Star Binary Ec 20117-4014 (=V4640 Sgr), T. Otani, T. D. Oswalt, A. E. Lynas-Gray, D. Kilkenny, C. Koen, M. Amaral, R. Jordan

Publications

Among the competing evolution theories for subdwarf-B (sdB) stars is the binary evolution scenario. EC 20117-4014 (=V4640 Sgr) is a spectroscopic binary system consisting of a pulsating sdB star and a late F main-sequence companion; however, the period and the orbit semimajor axes have not been precisely determined. This paper presents orbital characteristics of the EC 20117-4014 binary system using 20 years of photometric data. Periodic observed minus calculated (O–C) variations were detected in the two highest-amplitude pulsations identified in the EC 20117-4014 power spectrum, indicating the binary system's precise orbital period (P = 792.3 …

Kelvin-Helmholtz Instability: Lessons Learned And Ways Forward, A. Masson, K. Nykyri

Publications

The Kelvin–Helmholtz instability (KHI) is a ubiquitous phenomenon across the Universe, observed from 500 m deep in the oceans on Earth to the Orion molecular cloud. Over the past two decades, several space missions have enabled a leap forward in our understanding of this phenomenon at the Earth’s magnetopause. Key results obtained by these missions are first presented, with a special emphasis on Cluster and THEMIS. In particular, as an ideal instability, the KHI was not expected to produce mass transport. Simulations, later confirmed by spacecraft observations, indicate that plasma transport in Kelvin–Helmholtz (KH) vortices can arise during non-linear stage …