The Astrophysical Journal (Jan 2025)
The NANOGrav 12.5 yr Data Set: Probing Interstellar Turbulence and Precision Pulsar Timing with PSR J1903+0327
- Abra Geiger,
- James M. Cordes,
- Michael T. Lam,
- Stella Koch Ocker,
- Shami Chatterjee,
- Zaven Arzoumanian,
- Ava L. Battaglia,
- Harsha Blumer,
- Paul R. Brook,
- Olivia A. Combs,
- H. Thankful Cromartie,
- Megan E. DeCesar,
- Paul B. Demorest,
- Timothy Dolch,
- Justin A. Ellis,
- Robert D. Ferdman,
- Elizabeth C. Ferrara,
- Emmanuel Fonseca,
- Nate Garver-Daniels,
- Peter A. Gentile,
- Deborah C. Good,
- Megan L. Jones,
- Duncan R. Lorimer,
- Jing Luo,
- Ryan S. Lynch,
- Maura A. McLaughlin,
- Cherry Ng,
- David J. Nice,
- Timothy T. Pennucci,
- Nihan S. Pol,
- Scott M. Ransom,
- Renée Spiewak,
- Ingrid H. Stairs,
- Kevin Stovall,
- Joseph K. Swiggum,
- Sarah J. Vigeland
Affiliations
- Abra Geiger
- ORCiD
- Cornell Center for Astrophysics and Planetary Science and Department of Astronomy, Cornell University , Ithaca, NY 14853, USA ; [email protected]
- James M. Cordes
- ORCiD
- Cornell Center for Astrophysics and Planetary Science and Department of Astronomy, Cornell University , Ithaca, NY 14853, USA ; [email protected]
- Michael T. Lam
- ORCiD
- SETI Institute , 339 N. Bernardo Ave., Suite 200, Mountain View, CA 94043, USA; School of Physics and Astronomy, Rochester Institute of Technology , Rochester, NY 14623, USA; Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology , Rochester, NY 14623, USA
- Stella Koch Ocker
- ORCiD
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology , Pasadena, CA 91125, USA; The Observatories of the Carnegie Institution for Science , Pasadena, CA 91101, USA
- Shami Chatterjee
- ORCiD
- Cornell Center for Astrophysics and Planetary Science and Department of Astronomy, Cornell University , Ithaca, NY 14853, USA ; [email protected]
- Zaven Arzoumanian
- ORCiD
- X-Ray Astrophysics Laboratory, NASA Goddard Space Flight Center , Code 662, Greenbelt, MD 20771, USA
- Ava L. Battaglia
- ORCiD
- Department of Physics, Lafayette College , Easton, PA 18042, USA
- Harsha Blumer
- ORCiD
- Department of Physics and Astronomy, West Virginia University , P.O. Box 6315, Morgantown, WV 26506, USA; Center for Gravitational Waves and Cosmology, West Virginia University , Chestnut Ridge Research Building, Morgantown, WV 26505, USA
- Paul R. Brook
- ORCiD
- Institute for Gravitational Wave Astronomy and School of Physics and Astronomy, University of Birmingham , Edgbaston, Birmingham B15 2TT, UK
- Olivia A. Combs
- ORCiD
- Department of Physics, Lafayette College , Easton, PA 18042, USA
- H. Thankful Cromartie
- ORCiD
- National Research Council Research Associate, National Academy of Sciences , Washington, DC 20001, USA
- Megan E. DeCesar
- ORCiD
- George Mason University , Fairfax, VA 22030, USA
- Paul B. Demorest
- ORCiD
- National Radio Astronomy Observatory , 1003 Lopezville Rd., Socorro, NM 87801, USA
- Timothy Dolch
- ORCiD
- Department of Physics, Hillsdale College , 33 E. College Street, Hillsdale, MI 49242, USA; Eureka Scientific , 2452 Delmer Street, Suite 100, Oakland, CA 94602-3017, USA
- Justin A. Ellis
- School of Chemistry, University of East Anglia , Norwich NR4 7TJ, UK
- Robert D. Ferdman
- ORCiD
- School of Chemistry, University of East Anglia , Norwich NR4 7TJ, UK
- Elizabeth C. Ferrara
- ORCiD
- Department of Astronomy, University of Maryland , College Park, MD 20742, USA; Center for Research and Exploration in Space Science and Technology, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA; NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA
- Emmanuel Fonseca
- ORCiD
- Department of Physics and Astronomy, West Virginia University , P.O. Box 6315, Morgantown, WV 26506, USA; Center for Gravitational Waves and Cosmology, West Virginia University , Chestnut Ridge Research Building, Morgantown, WV 26505, USA
- Nate Garver-Daniels
- ORCiD
- Department of Physics and Astronomy, West Virginia University , P.O. Box 6315, Morgantown, WV 26506, USA; Center for Gravitational Waves and Cosmology, West Virginia University , Chestnut Ridge Research Building, Morgantown, WV 26505, USA
- Peter A. Gentile
- ORCiD
- Department of Physics and Astronomy, West Virginia University , P.O. Box 6315, Morgantown, WV 26506, USA; Center for Gravitational Waves and Cosmology, West Virginia University , Chestnut Ridge Research Building, Morgantown, WV 26505, USA
- Deborah C. Good
- ORCiD
- Department of Physics and Astronomy, University of Montana , 32 Campus Drive, Missoula, MT 59812, USA
- Megan L. Jones
- ORCiD
- Center for Gravitation, Cosmology and Astrophysics, Department of Physics, University of Wisconsin-Milwaukee , P.O. Box 413, Milwaukee, WI 53201, USA
- Duncan R. Lorimer
- ORCiD
- Department of Physics and Astronomy, West Virginia University , P.O. Box 6315, Morgantown, WV 26506, USA; Center for Gravitational Waves and Cosmology, West Virginia University , Chestnut Ridge Research Building, Morgantown, WV 26505, USA
- Jing Luo
- ORCiD
- Department of Astronomy & Astrophysics, University of Toronto , 50 Saint George Street, Toronto, ON M5S 3H4, Canada
- Ryan S. Lynch
- ORCiD
- Green Bank Observatory , P.O. Box 2, Green Bank, WV 24944, USA
- Maura A. McLaughlin
- ORCiD
- Department of Physics and Astronomy, West Virginia University , P.O. Box 6315, Morgantown, WV 26506, USA; Center for Gravitational Waves and Cosmology, West Virginia University , Chestnut Ridge Research Building, Morgantown, WV 26505, USA
- Cherry Ng
- ORCiD
- Dunlap Institute for Astronomy and Astrophysics, University of Toronto , 50 St. George St., Toronto, ON M5S 3H4, Canada
- David J. Nice
- ORCiD
- Department of Physics, Lafayette College , Easton, PA 18042, USA
- Timothy T. Pennucci
- ORCiD
- Institute of Physics and Astronomy, Eötvös Loránd University , Pázmány P. s. 1/A, 1117 Budapest, Hungary
- Nihan S. Pol
- ORCiD
- Department of Physics, Texas Tech University , Box 41051, Lubbock, TX 79409, USA
- Scott M. Ransom
- ORCiD
- National Radio Astronomy Observatory , 520 Edgemont Road, Charlottesville, VA 22903, USA
- Renée Spiewak
- ORCiD
- Jodrell Bank Centre for Astrophysics, University of Manchester , Manchester M13 9PL, UK
- Ingrid H. Stairs
- ORCiD
- Department of Physics and Astronomy, University of British Columbia , 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
- Kevin Stovall
- ORCiD
- National Radio Astronomy Observatory , 1003 Lopezville Rd., Socorro, NM 87801, USA
- Joseph K. Swiggum
- ORCiD
- Department of Physics, Lafayette College , Easton, PA 18042, USA
- Sarah J. Vigeland
- ORCiD
- Center for Gravitation, Cosmology and Astrophysics, Department of Physics, University of Wisconsin-Milwaukee , P.O. Box 413, Milwaukee, WI 53201, USA
- DOI
- https://doi.org/10.3847/1538-4357/add0b6
- Journal volume & issue
-
Vol. 986,
no. 2
p. 191
Abstract
Free electrons in the interstellar medium refract and diffract radio waves along multiple paths, resulting in angular and temporal broadening of radio pulses that limits pulsar timing precision. We determine multifrequency, multiepoch scattering times for the large dispersion measure millisecond PSR J1903+0327 by developing a three-component model for the emitted pulse shape that is convolved with a best-fit pulse broadening function (PBF) identified from a family of thin-screen and extended-media PBFs. We show that the scattering time, τ , at a fiducial frequency of 1500 MHz changes by approximately 10% over a 5.5 yr span with a characteristic timescale of approximately 100 days. We also constrain the spectral index and inner scale of the wavenumber spectrum of electron density variations along this line of sight. We find that the scaling law for τ versus radio frequency is strongly affected by any mismatch between the true and assumed PBF or between the true and assumed intrinsic pulse shape. We show using simulations that refraction is a plausible cause of the epoch dependence of τ , manifesting as changes in the PBF shape and 1/ e timescale. Finally, we discuss the implications of our scattering results on pulsar timing including time of arrival delays and dispersion measure misestimation.
Keywords
