Astrophysics and Astronomy Commons^™

Structural Evolution And Magnetic Properties Of Gd2hf2o7 Nanocrystals: Computational And Experimental Investigations, Madhab Pokhrel, Nicholas Dimakis, Gamage Chamath Dannangoda, Santosh K. Gupta, Karen S. Martirosyan, Yuanbing Mao

Physics & Astronomy Faculty Publications

Structural evolution in functional materials is a physicochemical phenomenon, which is important from a fundamental study point of view and for its applications in magnetism, catalysis, and nuclear waste immobilization. In this study, we used x-ray diffraction and Raman spectroscopy to examine the Gd₂Hf₂O₇ (GHO) pyrochlore, and we showed that it underwent a thermally induced crystalline phase evolution. Superconducting quantum interference device measurements were carried out on both the weakly ordered pyrochlore and the fully ordered phases. These measurements suggest a weak magnetism for both pyrochlore phases. Spin density calculations showed that the Gd^{3+ …}

A Thousand Days After The Merger: Continued X-Ray Emission From Gw170817, E. Troja, H. Van Eerten, Bing Zhang, G. Ryan, L. Piro, R. Ricci, B. O'Connor, M. H. Wieringa, S. B. Cenko, T. Sakamoto

Physics & Astronomy Faculty Research

Recent observations with the Chandra X-ray telescope continue to detect X-ray emission from the transient GW170817. In a total exposure of 96.6 ks, performed between 2020 March 9 and 16 (935–942 d after the merger), a total of 8 photons are measured at the source position, corresponding to a significance of ≈5σ. Radio monitoring with the Australian Telescope Compact Array (ATCA) shows instead that the source has faded below our detection threshold... (See full abstract in article).

Gravitational-Wave Constraints On The Equatorial Ellipticity Of Millisecond Pulsars, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, A. Adams, C. Adams, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, G. Allen, A. Allocca, P. A. Altin, A. Amato, S. Anand, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Ansoldi, J. M. Antelis, S. Antier, S. Appert, K. Arai, Tiffany Z. Summerscales

Faculty Publications

© 2020. The American Astronomical Society. All rights reserved.. We present a search for continuous gravitational waves from five radio pulsars, comprising three recycled pulsars (PSR J0437-4715, PSR J0711-6830, and PSR J0737-3039A) and two young pulsars: the Crab pulsar (J0534+2200) and the Vela pulsar (J0835-4510). We use data from the third observing run of Advanced LIGO and Virgo combined with data from their first and second observing runs. For the first time, we are able to match (for PSR J0437-4715) or surpass (for PSR J0711-6830) the indirect limits on gravitational-wave emission from recycled pulsars inferred from their observed spin-downs, and …

Staerkel Planetarium Can Give You Eyes In The Sky, Erik Johnson

Natural Science Faculty

People come to the William M. Staerkel Planetarium at Parkland College to see the wonders of the universe. The images you see on the dome and in the lobby of the planetarium are not possible to view if you are merely staring up at the night sky because these objects are too dim to see without using a telescope.

Toi-824 B: A New Planet On The Lower Edge Of The Hot Neptune Desert, J. A. Burt, L. D. Nielsen, S. N. Quinn, E. E. Mamajek, E. C. Matthews, G. Zhou, J. V. Seidel, C. X. Huang, E. Lopez, M. Soto, J. Otegi, K. G. Stassun, L. Kreidberg, K. A. Collins, J. D. Eastman, J. E. Rodriguez, A. Vanderburg, S. P. Halverson, J. K. Teske, S. X. Wang, R. P. Butler, F. Bouchy, X. Dumusque, D. Segransen, S. A. Shectman, J. D. Crane, F. Feng, B. T. Montet, A. D. Feinstein, Y. Beletski, E. Flowers, M. N. Günther, T. Daylan, K. I. Collins, D. M. Conti, T. Gan, Eric L.N. Jensen, J. F. Kielkopf, T.-G. Tan, R. Helled, C. Dorn, J. Haldemann, J. J. Lissauer, G. R. Ricker, R. Vanderspek, D. W. Latham, S. Seager, J. N. Winn, J. M. Jenkins, J. D. Twicken, J. C. Smith, P. Tenenbaum, S. Cartwright, T. Barclay, J. Pepper, G. Esquerdo, W. Fong

Physics & Astronomy Faculty Works

We report the detection of a transiting hot Neptune exoplanet orbiting TOI-824 (SCR J1448-5735), a nearby (d = 64 pc) K4V star, using data from the Transiting Exoplanet Survey Satellite. The newly discovered planet has a radius R_p = 2.93 ± 0.20 R_⊕ and an orbital period of 1.393 days. Radial velocity measurements using the Planet Finder Spectrograph and the High Accuracy Radial velocity Planet Searcher spectrograph confirm the existence of the planet, and we estimate its mass to be 18.47 ± 1.84 M_⊕. The planet's mean density is ρ_p = 4.03 (+0.98)/(-0.78) g …

Direct Confirmation Of The Radial-Velocity Planet Β Pictoris C, M. Nowak, S. Lacour, A. M. Lagrange, P. Rubini, J. Wang, T. Stolker, R. Abuter, A. Amorim, R. Asensio-Torres, M. Bauböck, M. Benisty, J. P. Berger, H. Beust, S. Blunt, A. Boccaletti, M. Bonnefoy, H. Bonnet, W. Brandner, F. Cantalloube, B. Charnay, E. Choquet, V. Christiaens, Y. Clénet, V. Coudé Du Foresto, A. Cridland, P. T. De Zeeuw, R. Dembet, J. Dexter, A. Drescher, G. Duvert, A. Eckart, F. Eisenhauer, Kimberly Ward-Duong, Et Al

Astronomy: Faculty Publications

Context. Methods used to detect giant exoplanets can be broadly divided into two categories: indirect and direct. Indirect methods are more sensitive to planets with a small orbital period, whereas direct detection is more sensitive to planets orbiting at a large distance from their host star. This dichotomy makes it difficult to combine the two techniques on a single target at once. Aims. Simultaneous measurements made by direct and indirect techniques offer the possibility of determining the mass and luminosity of planets and a method of testing formation models. Here, we aim to show how long-baseline interferometric observations guided by …

Very High Energy Studies Of The Crab Nebula, Madeline Claus, Ashna Coondiah, Omer Sajid

Annual Student Research Poster Session

The Crab Nebula is the remnant of a powerful stellar explosion first observed in 1054 AD and is the most studied object outside of our solar system. Our three-pronged research is focused on understanding the emission mechanisms responsible for energy range 100 MeV – 10 TeV. Our project consisted of 1) making light curves of Crab Nebula from Fermi-LAT’s data, 2) extending and investigating the pre-existing VERITAS light curve, and 3) phaseograms of the Crab Pulsar using VERITAS’s data.

Supervisor: Prof. Avery Archer, PhD

This research is supported by grants from the U.S. Department of Energy Office of Science, the …

Physics For Everyone, Charles Liu, Sarang Gopalakrishnan, Vadim Oganesyan

Open Educational Resources

The online educational resource Physics For Everyone is the scaffolding for a 3 contact hour, 3 credit general education course that will be offered for the first time at the CUNY College of Staten Island in the spring semester of 2021. This work has been generously supported by New America’s PIT-UN (Public Interest Technology University Network) challenge grant program, and is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License.

This slide deck provides the outline for the semester-long course. Each week’s lecture topics, with key points to be covered, are highlighted in two slides, which also list writing prompts, …

Gas Dynamics In Galaxy Clusters And Galaxies, Danial Ahmad Ariffin Lee

Student Works (2020-2029)

This thesis presents the results from a search for Neutral Hydrogen (HI) for the central region of the galaxy clusters A426 and A1367 using a 7m radio telescope. The resulting beam is substantially larger than previous studies, covering the central 2.5–3 Mpc diameter of these clusters. The detection of HI allows the mass of atomic gas associated with the cluster core to be estimated. The HI is not associated with any particular cluster member but present due to ram pressure and tidal stripping or recombination of intracluster gas. Overall results have revealed the presence of a significant mass of atomic …

Gravitational-Wave Constraints On The Equatorial Ellipticity Of Millisecond Pulsars, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, S. Mukherjee, V. Quetschke, Malik Rakhmanov, K. E. Ramirez, W. H. Wang

Physics & Astronomy Faculty Publications

We present a search for continuous gravitational waves from five radio pulsars, comprising three recycled pulsars (PSR J0437−4715, PSR J0711−6830, and PSR J0737−3039A) and two young pulsars: the Crab pulsar (J0534+2200) and the Vela pulsar (J0835−4510). We use data from the third observing run of Advanced LIGO and Virgo combined with data from their first and second observing runs. For the first time we are able to match (for PSR J0437−4715) or surpass (for PSR J0711−6830) the indirect limits on gravitational-wave emission from recycled pulsars inferred from their observed spin-downs, and constrain their equatorial ellipticities to be less than 10−8 …

Using Saoimage Ds9 & Hubble Space Telescope Data To Identify Globular Clusters In Ic 219, Emily Spicer, Alice Jacques, Benne Holwerda

Undergraduate Research Events

Globular clusters are tightly bound spherical clusters of stars located within the halo of elliptical and spiral galaxies. They are among the oldest stars found in a galaxy, and their presence and abundance in a galaxy’s halo offer insight on the age, composition, and formation of the galaxy.1 I used a Hubble Space Telescope (HST) image and SAOImage DS9, a powerful imaging tool used to analyze astronomical data, to identify the size and locate the position of globular cluster (GC) candidates in IC 219.

The Sizes Of Z ∼ 9-10 Galaxies Identified In The Brightest Of Reionizing Galaxies (Borg) Survey, Benne W. Holwerda, Joanna S. Bridge, Rebecca L. Steele, Samir Kusmic, Larry Bradley, Rachael Livermore, Stephanie Bernard, Alice Jacques

Faculty and Staff Scholarship

Redshift z = 9-10 object selection is the effective limit of Hubble Space Telescope (HST) imaging capability, even when confirmed with Spitzer. If only a few photometry data points are available, it becomes attractive to add criteria based on their morphology in these J- and H-band images. One could do so through visual inspection, a size criterion, or alternate morphometrics. We explore a vetted sample of Brightest of Reionizing Galaxies (BoRG) z ∼ 9 and z ∼ 10 candidate galaxies and the object rejected by Morishita+ to explore the utility of a size criterion in z = 9-10 candidate selection. …

Two Portions Of Sagittarius Stream In The Lamost Complete Spectroscopic Survey Of Pointing Area At Southern Galactic Cap, J. K. Zhao, Terry D. Oswalt, X. H. Ye, H. Wu, M. Yang, X. X. Xue, Y. Q. Chen, J. J. Zhan, G. Zhao

Publications

We constructed a sample of 13,798 stars with Teff , log g, [Fe/H], radial velocity, proper motions and parallaxes from LAMOST DR5 and Gaia DR2 in the LAMOST Complete Spectroscopic Survey of Pointing Area (LaCoSSPAr) at the Southern Galactic Cap consisting of areas A and B. Using the distributions in both proper motions and radial velocity, we detected very significant overdensi- ties in these two areas. These substructures most likely are portions of Sagittarius (Sgr) stream. With the Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm, 220 candidates stream members were identified. Based upon distance to the Sun and …

Interplay Of Quantum Phase Transition And Flat Band In Hybrid Lattices, Gui-Lei Zhu, Hamidreza Ramezani, Clive Emary, Jin-Hua Gao, Ying Wu, Xin-You Lü

Physics & Astronomy Faculty Publications

We establish a connection between quantum phase transitions (QPTs) and energy band theory in an extended Dicke-Hubbard lattice, where the periodical critical curves modulated by wave number k leads to rich equilibrium dynamics. Interestingly, the chiral-symmetry-protected flat band and the localization that it engenders exclusively occurs in the normal phase and disappears in the superradiant phase. This originates from the QPT induced simultaneous breaking up of the on-site resonance condition and off-site chiral symmetry of the system, which prohibits the destructive interference for obtaining a flat band. Our work offers an approach to identify different phases of the lattice via …

Optical Study Of Pks B1322-110, The Intra-Hour Variable Radio Source, Juan P. Madrid, Artem V. Tuntsov, Mischa Schirmer, Mark A. Walker, Carlos J. Donzelli, Keith W. Bannister, Hayley E. Bignall, Jamie Stevens, Cormac Reynolds, Simon Johnston

Physics & Astronomy Faculty Publications

Observations with the Australia Telescope Compact Array revealed intra-hour variations in the radio source PKS B1322-110 (Bignall et al. 2019). As part of an optical follow-up, we obtained Gemini Hα and Hα continuum (HαC) images of the PKS B1322-110 field. A robust 19 σ detection of PKS B1322- 110 in the Hα−HαC image prompted us to obtain the first optical spectrum of PKS B1322-110. With the Gemini spectrum we determine that PKS B1322-110 is a flat-spectrum radio quasar at a redshift of z = 3.007 ± 0.002. The apparent flux detected in the Hα filter is likely to originate from …

26 Results Of Hyperbolic Partial Differential Equations In B-Poly Basis, Muhammad I. Bhatti, Emilio Hinojosa

Physics & Astronomy Faculty Publications

A two-variable process to estimate results of Hyperbolic Partial Differentiation (HPD) equations in a B-Polynomial (B-Poly) bases is established. In the proposed process, a linear product of variable coefficients and B-Polys is manipulated to express the predicted solution of the HPD equation. The variable coefficients of the linear mixture in the results are concluded using Galerkin technique. The HPD equation is converted into a matrix which when inverted provided the unknown coefficients in the linear mixture of the solution. The anticipated solution is constructed from the variable coefficients and B-Poly basis set as a product with initial conditions implemented. Both …

Sensitivity And Performance Of The Advanced Ligo Detectors In The Third Observing Run, A. Buikema, C. Cahillane, G. L. Mansell, C. D. Blair, R. Abbott, C. Adams, R. Adhikari, K. E. Ramirez

Physics & Astronomy Faculty Publications

On April 1st, 2019, the Advanced Laser Interferometer Gravitational-Wave Observatory (aLIGO), joined by the Advanced Virgo detector, began the third observing run, a year-long dedicated search for gravitational radiation. The LIGO detectors have achieved a higher duty cycle and greater sensitivity to gravitational waves than ever before, with LIGO Hanford achieving angle-averaged sensitivity to binary neutron star coalescences to a distance of 111 Mpc, and LIGO Livingston to 134 Mpc with duty factors of 74.6% and 77.0% respectively. The improvement in sensitivity and stability is a result of several upgrades to the detectors, including doubled intracavity power, the addition of …

Gw190521: A Binary Black Hole Merger With A Total Mass Of 150  M⊙, R. Abbott, T. D. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of 85⁺²¹₋₁₄  M⊙ and 66⁺¹⁷₋₁₈  M⊙ (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only …

Directional Limits On Persistent Gravitational Waves Using Data From Advanced Ligo’S First Two Observing Runs, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration

Faculty Publications

We perform an unmodeled search for persistent, directional gravitational wave (GW) sources using data from the first and second observing runs of Advanced LIGO. We do not find evidence for any GW signals. We place limits on the broadband GW flux emitted at 25 Hz from point sources with a power law spectrum at F_α,Θ<(0.05–25)×10⁻⁸  erg cm⁻² s⁻¹ Hz⁻¹ and the (normalized) energy density spectrum in GWs at 25 Hz from extended sources at Ω_α(Θ)<(0.19–2.89)×10⁻⁸  sr⁻¹ where α is the spectral index of the energy density spectrum. These represent improvements of …

Gw190521: A Binary Black Hole Merger With A Total Mass Of 150 M⊙, R. Abbott, T. D. Abbott, A. Aich, G. Bissenbayeva, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, P. K. Roy, W. H. Wang, A. K. Zadrozny

Physics & Astronomy Faculty Publications

On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of 85+21−14  M⊙ and 66+17−18  M⊙ (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only a 0.32% probability of …