Article
Astronomy & Astrophysics
L. S. Oswald, A. Karastergiou, S. Johnston
Summary: The conventional model of pulsar polarization fails to explain certain properties observed in the population of radio pulsars, such as frequency evolution of polarization, deviations in linear polarization angles, and presence of circular polarization features. To address this, the partial-coherence model is presented as an explanation for the co-occurrence of these features and a source of circular polarization in radio pulsar profiles. The mathematical principles and its ability to explain observed features on both population and individual pulsar level are described, highlighting its importance in understanding pulsar geometries and radio emission.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
E. Gugercinoglu, M. Y. Ge, J. P. Yuan, S. Q. Zhou
Summary: This study presents timing solutions from observations of gamma-ray pulsars, identifying new glitches, analyzing their properties, and obtaining important information about the structure of neutron stars. The observed results are in qualitative agreement with the theoretical predictions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
E. A. Brylyakova, S. A. Tyul'bashev
Summary: Utilizing five years of monitoring observations, a blind search for pulses was conducted for PSR B0320+39 and RRAT J0139+33, revealing a higher number of pulses for the former and a lower number of pulses with giant pulse characteristics for the latter. The signal-to-noise ratios for the strongest pulses were found to be 262 and 154 for B0320+39 and J0139+33 respectively, with different distributions of detected pulses based on S/N units for the pulsar and the rotating transient.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
A. Bobakov, A. Karpova, S. Zharikov, A. Yu Kirichenko, Yu A. Shibanov, D. A. Zyuzin
Summary: This article presents the optical spectroscopy results of three binary millisecond pulsars, showing that the companions of J0621+2514 and J2317+1439 are DA-type white dwarfs with relatively high temperatures of 8600 +/- 200 and 9600 +/- 2000 K, respectively, while the companion of J2302+4442 is a cooler DA-type white dwarf with a temperature below 6000 K.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
J. Dyks
Summary: Radio pulsars display unexplained phenomena in their pulse profiles, such as the core-cone structure and frequency evolution. The author proposes that these phenomena can be explained through the geometric properties of inverse Compton scattering. The observed bifurcated components can be interpreted as magnified microbeams of curvature radiation that have been upshifted in frequency and preserved in width by beam-copying scattering.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
J. Dyks
Summary: This study reveals that the complex behavior of single radio pulses from pulsars is mainly a result of the sector structure of the observed relatively simple radio beam, leading to a diversity of pulsation modes and nulling. The research also demonstrates that the classical drift-period-folded patterns are caused by the slow drift of the sector beam.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Lorenzo Iorio
Summary: This study discusses the method of using the Lense-Thirring effect to measure or constrain the moment of inertia in a double pulsar system. The research results show that the effects can be accurately tested by determining subtle variations at different scales.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Tao Wang, J. L. Han, C. Wang, P. F. Wang, D. J. Zhou
Summary: The bright pulsar PSR B0329+54 has two emission modes, with the newly identified core-weak mode showing a weakening of the central component of the pulse profile. Observations indicate that individual pulse components, including the core and leading and trailing peaks, exhibit related variations forming a regular pattern in the phase-time plot. This pattern lasts for several periods, involving changes in intensity and phase of the core and other components.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
J. Dyks, P. Weltevrede, C. Ilie
Summary: The radio emission of pulsar B1451-68 displays orthogonal polarization modes, reversed power ratios, and interference patterns in profile components. These properties can be explained by coherent OPM transitions and superposition of coplanar oscillations, leading to minima in the pulse profile and the illusion of separate components.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
W. C. Jing, J. L. Han, Tao Hong, Chen Wang, X. Y. Gao, L. G. Hou, D. J. Zhou, J. Xu, Z. L. Yang
Summary: Using the FAST telescope, the neutral hydrogen (HI) absorption spectrum of PSR B0458+46 was observed, revealing two absorption lines. Based on the Galactic rotation curve, the distance of PSR B0458+46 was determined to be 2.7 kpc, indicating that it is not associated with SNR HB9. Additionally, a new high-velocity HI cloud was detected in the direction of this pulsar.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Sk Minhajur Rahaman, Rahul Basu, Dipanjan Mitra, George Melikidze
Summary: This study conducted a detailed single pulse polarimetric analysis of the radio emission from the pulsar J2321+6024, revealing four distinct conal components and three emission modes (A, B, and ABN) with subpulse drifting. A new emission state, mode C, was also identified. The drifting periodicities and polarization behavior varied among different modes and components, with no correlation found between emission modes and polarization behavior. The study used the Partially Screened Gap model to investigate the connection between drifting, mode changing, and nulling.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
K. Liu, J. Antoniadis, C. G. Bassa, S. Chen, I Cognard, M. Gaikwad, H. Hu, J. Jang, G. H. Janssen, R. Karuppusamy, M. Kramer, K. J. Lee, R. A. Main, G. Mall, J. W. McKee, M. B. Mickaliger, D. Perrodin, S. A. Sanidas, B. W. Stappers, L. Wang, W. W. Zhu, M. Burgay, R. Concu, A. Corongiu, A. Melis, M. Pilia, A. Possenti
Summary: This study reports the detection of quasi-periodic micro-structure in three millisecond pulsars using high time resolution data. The occurrence rate of micro-structure is consistent among pulses with different peak flux densities, and it often exhibits high linear polarization. The results provide valuable insights into the dependency of micro-structure properties and its potential link to fast radio bursts.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Stefan Oslowski, Mark A. Walker
Summary: A pulsar dynamic spectrum is a digital hologram that encodes information on the propagation paths of signals. We present a new method, called H-FISTA, for phase retrieval in pulsar spectroscopy using the Fast Iterative Shrinkage Thresholding Algorithm. Our algorithm obtains sparse models of the wavefield in a hierarchical approach, leading to a fully dense model that allows the discovery of faint signals. The performance of our method is demonstrated on synthetic test cases and real data.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
M. Vivekanand
Summary: The study revealed that the edges of the first and second peaks of Crab pulsar's high-resolution folded light curve at soft X-ray energies are only statistically similar in a narrow phase range.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Qijun Zhi, Xin Xu, Lunhua Shang, Juntao Bai, Shijun Dang, Jiguang Lu, Shi Dai, Rushuang Zhao, Zhigang Wen, Guojun Qiao, Aijun Dong
Summary: In this study, we observed PSR B0820 + 02 using FAST and found four distinct subpulse drifting modes (A, B, C, and D), with drifting periodicities of 4.3P(1), 6.4P(1), 8.2P(1), and 10.3P(1) (P-1 is the pulse period), respectively. We also compared the energy distribution of single pulses in each mode and found that mode A has the highest energy while mode D has the lowest energy. Finally, we interpreted the drift modes in terms of the carousel model and suggested that the carousel rotation period of P-4 lies in the range 29P(1)-33P(1).
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
E. Parent, H. Sewalls, P. C. C. Freire, T. Matheny, A. G. Lyne, B. B. P. Perera, F. Cardoso, M. A. McLaughlin, B. Allen, A. Brazier, F. Camilo, S. Chatterjee, J. M. Cordes, F. Crawford, J. S. Deneva, F. A. Dong, R. D. Ferdman, E. Fonseca, J. W. T. Hessels, V. M. Kaspi, B. Knispel, J. van Leeuwen, R. S. Lynch, B. M. Meyers, J. W. McKee, M. B. Mickaliger, C. Patel, S. M. Ransom, A. Rochon, P. Scholz, I. H. Stairs, B. W. Stappers, C. M. Tan, W. W. Zhu
Summary: This article presents new discoveries and results from the PALFA survey, including precise measurements of astrometric and spin parameters, as well as flux density and scatter broadening measurements. The findings include young pulsars without supernova remnant associations, mode-changing, nulling and intermittent pulsars, and glitches in some pulsars. The study also compares the PALFA discoveries to the known population, revealing differences in distance and dispersion measures. Overall, the discoveries contribute to our understanding of pulsar magnetosphere physics and suggest a larger population of these objects in the Galaxy than previously thought.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
N. T. Palliyaguru, B. B. P. Perera, M. A. McLaughlin, S. Oslowski, G. L. Siebert
Summary: Single-pulse studies on three bright millisecond pulsars reveal the detection of single pulses at 4.5 GHz for PSRs J1022+1001 and J1713+0747 for the first time. The linear polarization fraction in the average profile of these two pulsars is significantly reduced at 4.5 GHz, supporting the expected deviation from a dipolar field at the pulsar surface. PSR J1713+0747 shows hints of orthogonal modes in its single pulses. More sensitive multifrequency observations are needed to confirm these findings. Furthermore, the observed jitter noise contributions and improved timing using selective bright-pulse timing are consistent with previous studies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
S. Singh, J. Roy, B. Bhattacharyya, U. Panda, B. W. Stappers, M. A. McLaughlin
Summary: The FFT-based periodicity search methods are efficient for searching for millisecond and binary pulsars, but have reduced sensitivity for long period and short duty cycle pulsars. The FFA search algorithm provides superior sensitivity for these types of pulsars. In the GHRSS survey, we used the FFA-based pipeline to search for isolated pulsars and discovered six new pulsars, including four with narrow duty cycles.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Jacob E. Turner, Daniel R. Stinebring, Maura A. McLaughlin, Anne M. Archibald, Timothy Dolch, Ryan S. Lynch
Summary: This study simulates scattering delays from the interstellar medium and compares three estimation methods for recovering these delays in pulsar timing data. The results show that fitting a Lorentzian or Gaussian distribution to an autocorrelation function, or using cyclic spectroscopy to extract the interstellar medium's impulse response function, are all accurate in recovering scattering delays on average. However, autocorrelation function estimators have large variances, even at high signal-to-noise ratio (S/N). Given sufficient S/N, cyclic spectroscopy is more accurate than both Gaussian and Lorentzian fitting for recovering scattering delays at specific epochs, indicating that cyclic spectroscopy is a superior method for scattering estimation in high-quality data.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
J. K. Swiggum, Z. Pleunis, E. Parent, D. L. Kaplan, M. A. McLaughlin, I. H. Stairs, R. Spiewak, G. Y. Agazie, P. Chawla, M. E. DeCesar, T. Dolch, W. Fiore, E. Fonseca, A. G. Istrate, V. M. Kaspi, V. I. Kondratiev, J. van Leeuwen, L. Levin, E. F. Lewis, R. S. Lynch, A. E. McEwen, H. Al Noori, S. M. Ransom, X. Siemens, M. Surnis
Summary: We provide timing solutions for 12 pulsars discovered in the Green Bank North Celestial Cap 350 MHz pulsar survey, including six millisecond pulsars, a double neutron star system, and a pulsar orbiting a massive white dwarf companion. Our timing solutions are based on Green Bank Telescope data and a dedicated timing campaign, allowing us to measure proper motions and estimate space velocities for three pulsars in the sample. We have also detected the advance of periastron for one pulsar, allowing for the measurement of the total mass of the double neutron star system. Long-term pulsar timing is crucial for understanding these systems post-discovery.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
A. D. Cameron, M. Bailes, D. J. Champion, P. C. C. Freire, M. Kramer, M. A. McLaughlin, C. Ng, A. Possenti, A. Ridolfi, T. M. Tauris, H. M. Wahl, N. Wex
Summary: PSR J1757-1854 is a double neutron star binary system in our Galaxy, which exhibits relativistic properties and offers a potential for testing relativistic gravity. Through a 6-year observational campaign, we confirmed the presence of geodetic precession in PSR J1757-1854 and updated its timing and mass constraints. However, the precision of the radiative test of gravity is limited by the unknown distance to the pulsar. We also searched for pulsations from the companion neutron star but obtained negative results. Nevertheless, the system presents opportunities for future relativistic tests of gravity, with expected constraints on the change in the semimajor axis and the relativistic orbital deformation parameter.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Megan L. Jones, David L. Kaplan, Maura A. McLaughlin, Duncan R. Lorimer
Summary: While neutron star-black hole binaries have been detected, the existence of a pulsar-black hole binary has not been confirmed. Long-period binaries could be hidden by other timing effects and go undetected. This study assesses the possibility of pulsars having unknown companions in long-period binaries and puts constraints on the range of undetected binary properties. It finds that some pulsars may still have binary companions and provides limits on orbital period and longitude of periastron for a few pulsars with higher-order frequency derivatives.
ASTROPHYSICAL JOURNAL
(2023)
Correction
Astronomy & Astrophysics
Megan L. Jones, David L. Kaplan, Maura A. Mclaughlin, Duncan R. Lorimer
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
W. Fiore, L. Levin, M. A. McLaughlin, A. Anumarlapudi, D. L. Kaplan, J. K. Swiggum, G. Y. Agazie, R. Bavisotto, P. Chawla, M. E. DeCesar, T. Dolch, E. Fonseca, V. M. Kaspi, Z. Komassa, V. I. Kondratiev, J. van Leeuwen, E. F. Lewis, R. S. Lynch, A. E. McEwen, R. Mundorf, H. Al Noori, E. Parent, Z. Pleunis, S. M. Ransom, X. Siemens, R. Spiewak, I. H. Stairs, M. Surnis, T. J. Tobin
Summary: We present timing solutions for 21 pulsars discovered in 350 MHz surveys using the Green Bank Telescope (GBT). Most of the observations were made with the GBT at 820 MHz. We found new pulsars and updated the timing solutions for some previously known pulsars.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Paul T. Baker, Bence Becsy, Laura Blecha, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, J. Andrew Casey-Clyde, Maria Charisi, Shami Chatterjee, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan E. DeCesar, Paul B. Demorest, Timothy Dolch, Brendan Drachler, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Emiko Gardiner, Nate Garver-Daniels, Peter A. Gentile, Joseph Glaser, Deborah C. Good, Kayhan Gultekin, Jeffrey S. Hazboun, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zolt Kelley, Matthew Kerr, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, T. Joseph W. Lazio, Natalia Lewandowska, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Chiara M. F. Mingarelli, Andrea Mitridate, Cherry Ng, David J. Nice, Stella Koch Ocker, Ken D. Olum, Timothy T. Pennucci, Benetge B. P. Perera, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Levi Schult, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Abhimanyu Susobhanan, Joseph K. Swiggum, Stephen R. Taylor, Jacob E. Turner, Caner Unal, Michele Vallisneri, Sarah J. Vigeland, Haley M. Wahl, Caitlin A. Witt, Olivia Young
Summary: The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has reported evidence for the presence of a uniform gravitational-wave background (GWB). Various methods were used to search for anisotropy in the GWB, but no significant evidence was found. The upper limit on dipole anisotropy was found to be approximately 27%, similar to the upper limit derived under the constraint of positive power everywhere. Conservative estimates on the anisotropy expected from a random distribution of SMBHB systems were also derived using astrophysical simulations.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Paul T. Baker, Bence Becsy, Laura Blecha, Alexander Bonilla, Adam Brazier, Paul Brook, Sarah Burke-Spolaor, Rand Burnette, Robin Case, J. Andrew Casey-Clyde, Maria Charisi, Shami Chatterjee, Katerina Chatziioannou, Belinda D. Cheeseboro, Siyuan Chen, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Curt E. Cutler, Daniel J. D'Orazio, Megan E. DeCesar, Dallas DeGan, Paul B. Demorest, Heling Deng, Timothy Dolch, Brendan Drachler, Elizabeth Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Emiko Gardiner, Nate Garver-Daniels, Peter A. Gentile, Kyle A. Gersbach, Joseph Glaser, Deborah C. Good, Kayhan Gultekin, Jeffrey Hazboun, Sophie J. Hourihane, Kristina Islo, Ross L. Jennings, Aaron Johnson, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Matthew Kerr, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, T. Joseph W. Lazio, Natalia B. Lewandowska, Tyson Littenberg, Tingting Liu, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Alexander McEwen, James A. McKee, Maura A. McLaughlin, Natasha McMann, Bradley M. Meyers, Patrick M. Meyers, Chiara M. F. Mingarelli, Andrea Mitridate, Priyamvada Natarajan, Cherry J. Ng, David J. Nice, Stella Koch Ocker, Ken T. Olum, Timothy Pennucci, Benetge B. P. Perera, Polina Petrov, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph C. Romano, Jessie C. Runnoe, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Levi Schult, Brent Shapiro-Albert, Xavier Siemens, Joseph Simon, Magdalena S. Siwek, Ingrid H. Stairs, Daniel Stinebring, Kevin Stovall, Jerry P. Sun, Abhimanyu Susobhanan, Joseph K. Swiggum, Jacob Taylor, Stephen R. Taylor, Jacob E. Turner, Caner Unal, Michele Vallisneri, Sarah J. Vigeland, Jeremy M. Wachter, Haley M. Wahl, Qiaohong Wang, Caitlin Witt, David Wright, Olivia Young
Summary: The NANOGrav 15 yr data set provides evidence for the presence of a low-frequency gravitational-wave background, possibly originating from distributed supermassive black hole binaries in the universe. The study shows that astrophysically motivated models of binary populations can reproduce the observed low-frequency gravitational-wave spectrum, emphasizing the importance of accurately modeling binary evolution. Additionally, the results suggest the need for parameters to be at extreme values or notably different from standard expectations to explain the implied GWB amplitude.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
Chen-Chen Miao, Victoria Blackmon, Wei-Wei Zhu, Dong-Zi Li, Ming-Yu Ge, Xiao-Peng You, Maura Mclaughlin, Di Li, Na Wang, Pei Wang, Jia-Rui Niu, M. Cruces, Jian-Ping Yuan, Jun-Tao Bai, D. J. Champion, Yu-Tong Chen, Ming-Min Chi, P. C. C. Freire, Yi Feng, Zhen-Ye Gan, M. Kramer, Fei-Fei Kou, Yu-Xi Li, Xue-Li Miao, Ling-Qi Meng, Chen-Hui Niu, Sheng-Nan Sun, Zhong-Yi Sun, H. M. Tedila, Shuang-Qiang Wang, Qing-Dong Wu, Jing-Bo Wang, Zhi-Gang Wen, Shen Wang, Ya-Biao Wang, Cheng-Jie Wang, Meng-Yao Xue, You-Ling Yue, Mao Yuan, Ju-Mei Yao, Wen-Ming Yan, Ru-Shuang Zhao, Lei Zhang, De Zhao
Summary: In this study, radio observations of an eclipsing black widow pulsar were reported, revealing oscillatory polarization angle changes and dispersion measure variations. The results suggest that the oscillatory magnetic fields outside the companion's magnetosphere may originate from the pulsar wind.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2023)
Article
Computer Science, Interdisciplinary Applications
Maura McLaughlin, Nicholas Kisseberth, Sue Ann Heatherly, Harsha Blumer, Timothy Olszanski, Claire Stirm, Jack A. Smith, Duncan Lorimer
Summary: The Pulsar Science Collaboratory (PSC) is a research project that engages high school students, teachers, and undergraduates in searching for pulsars using radio telescopes. It aims to stimulate student interest in STEM careers, train teachers in authentic research, promote student use of information technologies, and assist the research community through pulsar discoveries. Participants gain access to radio astronomy data after completing training workshops and passing a certification test.
COMPUTING IN SCIENCE & ENGINEERING
(2023)
