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Modeling nonstationary noise in pulsar timing array data analysis (2024)
Journal Article
Falxa, M., Antoniadis, J., Champion, D. J., Cognard, I., Desvignes, G., Guillemot, L., Hu, H., Janssen, G., Jawor, J., Karuppusamy, R., Keith, M., Kramer, M., Lackeos, K., Liu, K., McKee, J. W., Perrodin, D., Sanidas, S., Shaifullah, G., & Theureau, G. (2024). Modeling nonstationary noise in pulsar timing array data analysis. Physical Review D, 109(12), Article 123010. https://doi.org/10.1103/PhysRevD.109.123010

Pulsar timing array (PTA) collaborations recently reported evidence for the presence of a gravitational wave background (GWB) in their datasets. The main candidate that is expected to produce such a GWB is the population of supermassive black hole bi... Read More about Modeling nonstationary noise in pulsar timing array data analysis.

The second data release from the European Pulsar Timing Array: IV. Implications for massive black holes, dark matter, and the early Universe (2024)
Journal Article
EPTA Collaboration and InPTA Collaboration, Antoniadis, J., Arumugam, P., Arumugam, S., Babak, S., Bagchi, M., Bak Nielsen, A.-S., Bassa, C. G., Bathula, A., Berthereau, A., Bonetti, M., Bortolas, E., Brook, P. R., Burgay, M., Caballero, R. N., Chalumeau, A., Champion, D. J., Chanlaridis, S., Chen, S., Cognard, I., …Valtolina, S. (2024). The second data release from the European Pulsar Timing Array: IV. Implications for massive black holes, dark matter, and the early Universe. Astronomy and Astrophysics, 685, Article A94. https://doi.org/10.1051/0004-6361/202347433

The European Pulsar Timing Array (EPTA) and Indian Pulsar Timing Array (InPTA) collaborations have measured a low-frequency common signal in the combination of their second and first data releases, respectively, with the correlation properties of a g... Read More about The second data release from the European Pulsar Timing Array: IV. Implications for massive black holes, dark matter, and the early Universe.

Comparing Recent Pulsar Timing Array Results on the Nanohertz Stochastic Gravitational-wave Background (2024)
Journal Article
Agazie, G., Antoniadis, J., Anumarlapudi, A., Archibald, A. M., Arumugam, P., Arumugam, S., Arzoumanian, Z., Askew, J., Babak, S., Bagchi, M., Bailes, M., Nielsen, A.-S. B., Baker, P. T., Bassa, C. G., Bathula, A., Bécsy, B., Berthereau, A., Bhat, N. D. R., Blecha, L., Bonetti, M., …The International Pulsar Timing Array Collaboration. (2024). Comparing Recent Pulsar Timing Array Results on the Nanohertz Stochastic Gravitational-wave Background. The Astrophysical journal, 966(1), Article 105. https://doi.org/10.3847/1538-4357/ad36be

The Australian, Chinese, European, Indian, and North American pulsar timing array (PTA) collaborations recently reported, at varying levels, evidence for the presence of a nanohertz gravitational-wave background (GWB). Given that each PTA made differ... Read More about Comparing Recent Pulsar Timing Array Results on the Nanohertz Stochastic Gravitational-wave Background.

Pulsar scintillation through thick and thin: bow shocks, bubbles, and the broader interstellar medium (2023)
Journal Article
Ocker, S. K., Cordes, J. M., Chatterjee, S., Stinebring, D. R., Dolch, T., Giannakopoulos, C., Pelgrims, V., McKee, J. W., & Reardon, D. J. (2024). Pulsar scintillation through thick and thin: bow shocks, bubbles, and the broader interstellar medium. Monthly notices of the Royal Astronomical Society, 527(3), 7568-7587. https://doi.org/10.1093/mnras/stad3683

Observations of pulsar scintillation are among the few astrophysical probes of very small-scale ( au) phenomena in the interstellar medium (ISM). In particular, characterization of scintillation arcs, including their curvature and intensity distribut... Read More about Pulsar scintillation through thick and thin: bow shocks, bubbles, and the broader interstellar medium.

The black widow pulsar J1641+8049 in the optical, radio, and X-rays (2023)
Journal Article
Kirichenko, A. Y., Zharikov, S. V., Karpova, A. V., Fonseca, E., Zyuzin, D. A., Shibanov, Y. A., López, E. A., Gilfanov, M. R., Cabrera-Lavers, A., Geier, S., Dong, F. A., Good, D. C., McKee, J. W., Meyers, B. W., Stairs, I. H., McLaughlin, M. A., & Swiggum, J. K. (2024). The black widow pulsar J1641+8049 in the optical, radio, and X-rays. Monthly notices of the Royal Astronomical Society, 527(3), 4563-4572. https://doi.org/10.1093/mnras/stad3391

PSR J1641+8049 is a 2 ms black widow pulsar with the 2.2 h orbital period detected in the radio and γ -rays. We performed new phase-resolved multiband photometry of PSR J1641+8049 using the OSIRIS instrument at the Gran Telescopio Canarias. The obtai... Read More about The black widow pulsar J1641+8049 in the optical, radio, and X-rays.

Periodic interstellar scintillation variations of PSRs J0613–0200 and J0636+5128 associated with the Local Bubble shell (2023)
Journal Article
Liu, Y., Main, R. A., Verbiest, J. P., Wu, Z., Ambalappat, K. M., Lu, J., Champion, D. J., Cognard, I., Guillemot, L., Liu, K., McKee, J. W., Porayko, N., Shaifullah, G. M., & Theureau, G. (2023). Periodic interstellar scintillation variations of PSRs J0613–0200 and J0636+5128 associated with the Local Bubble shell. Science China Physics, Mechanics and Astronomy, 66(11), Article 119512. https://doi.org/10.1007/s11433-023-2182-6

Annual variations of interstellar scintillation can be modelled to constrain parameters of the ionized interstellar medium. If a pulsar is in a binary system, then investigating the orbital parameters is possible through analysis of the orbital varia... Read More about Periodic interstellar scintillation variations of PSRs J0613–0200 and J0636+5128 associated with the Local Bubble shell.

Robust parameter estimation from pulsar timing data (2022)
Journal Article
Samajdar, A., Shaifullah, G. M., Sesana, A., Antoniadis, J., Burgay, M., Chen, S., Cognard, I., Guillemot, L., Kramer, M., McKee, J. W., Mickaliger, M. B., Theureau, G., & Van Der Wateren, E. (2022). Robust parameter estimation from pulsar timing data. Monthly notices of the Royal Astronomical Society, 517(1), 1460-1468. https://doi.org/10.1093/mnras/stac2810

Recently, global pulsar timing arrays have released results from searching for a nano-Hertz gravitational wave background signal. Although there has not been any definite evidence of the presence of such a signal in residuals of pulsar timing data ye... Read More about Robust parameter estimation from pulsar timing data.

Long-term scintillation studies of EPTA pulsars I. Observations and basic results (2022)
Journal Article
Liu, Y., Verbiest, J. P., Main, R. A., Wu, Z., Ambalappat, K. M., Champion, D. J., Cognard, I., Guillemot, L., Gaikwad, M., Janssen, G. H., Kramer, M., Keith, M. J., Karuppusamy, R., Künkel, L., Liu, K., McKee, J. W., Mickaliger, M. B., Stappers, B. W., Shaifullah, G. M., & Theureau, G. (2022). Long-term scintillation studies of EPTA pulsars I. Observations and basic results. Astronomy and Astrophysics, 664, Article A116. https://doi.org/10.1051/0004-6361/202142552

Context. Interstellar scintillation analysis of pulsars allows us to probe the small-scale distribution and inhomogeneities of the ionized interstellar medium. From the frequency scale of scintillation, one can estimate the geometric time delays from... Read More about Long-term scintillation studies of EPTA pulsars I. Observations and basic results.

The Large Dispersion and Scattering of FRB 20190520B Are Dominated by the Host Galaxy (2022)
Journal Article
Koch Ocker, S., Cordes, J. M., Chatterjee, S., Niu, C. H., Li, D., McKee, J. W., Law, C. J., Tsai, C. W., Anna-Thomas, R., Yao, J. M., & Cruces, M. (2022). The Large Dispersion and Scattering of FRB 20190520B Are Dominated by the Host Galaxy. The Astrophysical journal, 931(2), Article 87. https://doi.org/10.3847/1538-4357/ac6504

The repeating fast radio burst FRB 20190520B is localized to a galaxy at z = 0.241, much closer than expected given its dispersion measure DM = 1205 ± 4 pc cm-3. Here we assess implications of the large DM and scattering observed from FRB 20190520B f... Read More about The Large Dispersion and Scattering of FRB 20190520B Are Dominated by the Host Galaxy.

Searches for Gravitational Waves from Known Pulsars at Two Harmonics in the Second and Third LIGO-Virgo Observing Runs (2022)
Journal Article
Abbott, R., Abe, H., Acernese, F., Ackley, K., Adhikari, N., Adhikari, R., Adkins, V., Adya, V., Affeldt, C., Agarwal, D., Agathos, M., Agatsuma, K., Aggarwal, N., Aguiar, O., Aiello, L., Ain, A., Ajith, P., Akutsu, T., Albanesi, S., Alfaidi, R., …Weltevrede, P. (2022). Searches for Gravitational Waves from Known Pulsars at Two Harmonics in the Second and Third LIGO-Virgo Observing Runs. The Astrophysical journal, 935(1), Article 1. https://doi.org/10.3847/1538-4357/ac6acf

We present a targeted search for continuous gravitational waves (GWs) from 236 pulsars using data from the third observing run of LIGO and Virgo (O3) combined with data from the second observing run (O2). Searches were for emission from the l = m = 2... Read More about Searches for Gravitational Waves from Known Pulsars at Two Harmonics in the Second and Third LIGO-Virgo Observing Runs.