skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Swift , XMM - Newton , and NuSTAR Observations of PSR J2032+4127/MT91 213

Abstract

We report our recent Swift , NuSTAR , and XMM - Newton X-ray and Lijiang optical observations on PSR J2032+4127/MT91 213, the γ -ray binary candidate with a period of 45–50 years. The coming periastron of the system was predicted to be in 2017 November, around which high-energy flares from keV to TeV are expected. Recent studies with Chandra and Swift X-ray observations taken in 2015/2016 showed that its X-ray emission has been brighter by a factors of ∼10 than that before 2013, probably revealing some ongoing activities between the pulsar wind and the stellar wind. Our new Swift /XRT lightcurve shows no strong evidence of a single vigorous brightening trend, but rather several strong X-ray flares on weekly to monthly timescales with a slowly brightening baseline, namely the low state. The NuSTAR and XMM - Newton observations taken during the flaring and the low states, respectively, show a denser environment and a softer power-law index during the flaring state, implying that the pulsar wind interacted with the stronger stellar winds of the companion to produce the flares. These precursors would be crucial in studying the predicted giant outburst from this extreme γ -ray binary during the periastron passage inmore » late 2017.« less

Authors:
 [1];  [2];  [3];  [4];  [5];  [6]
  1. Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)
  2. Astrophysics, Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom)
  3. School of Physics and Astronomy, Sun Yat-sen University, Zhuhai 519082 (China)
  4. Yunnan Observatories, Chinese Academy of Sciences, 396 Yangfangwang, Guandu District, Kunming 650216 (China)
  5. Institute of Particle Physics and Astronomy, Huazhong University of Science and Technology (China)
  6. Department of Astronomy and Space Science, Chungnam National University, Daejeon (Korea, Republic of)
Publication Date:
OSTI Identifier:
22663422
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 843; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMIC GAMMA SOURCES; COSMIC X-RAY SOURCES; EMISSION; KEV RANGE; PULSARS; STARS; STELLAR WINDS; TEV RANGE

Citation Formats

Li, K. L., Kong, A. K. H., Tam, P. H. T., Hou, X., Takata, J., and Hui, C. Y., E-mail: liliray@pa.msu.edu. Swift , XMM - Newton , and NuSTAR Observations of PSR J2032+4127/MT91 213. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA784E.
Li, K. L., Kong, A. K. H., Tam, P. H. T., Hou, X., Takata, J., & Hui, C. Y., E-mail: liliray@pa.msu.edu. Swift , XMM - Newton , and NuSTAR Observations of PSR J2032+4127/MT91 213. United States. doi:10.3847/1538-4357/AA784E.
Li, K. L., Kong, A. K. H., Tam, P. H. T., Hou, X., Takata, J., and Hui, C. Y., E-mail: liliray@pa.msu.edu. Mon . "Swift , XMM - Newton , and NuSTAR Observations of PSR J2032+4127/MT91 213". United States. doi:10.3847/1538-4357/AA784E.
@article{osti_22663422,
title = {Swift , XMM - Newton , and NuSTAR Observations of PSR J2032+4127/MT91 213},
author = {Li, K. L. and Kong, A. K. H. and Tam, P. H. T. and Hou, X. and Takata, J. and Hui, C. Y., E-mail: liliray@pa.msu.edu},
abstractNote = {We report our recent Swift , NuSTAR , and XMM - Newton X-ray and Lijiang optical observations on PSR J2032+4127/MT91 213, the γ -ray binary candidate with a period of 45–50 years. The coming periastron of the system was predicted to be in 2017 November, around which high-energy flares from keV to TeV are expected. Recent studies with Chandra and Swift X-ray observations taken in 2015/2016 showed that its X-ray emission has been brighter by a factors of ∼10 than that before 2013, probably revealing some ongoing activities between the pulsar wind and the stellar wind. Our new Swift /XRT lightcurve shows no strong evidence of a single vigorous brightening trend, but rather several strong X-ray flares on weekly to monthly timescales with a slowly brightening baseline, namely the low state. The NuSTAR and XMM - Newton observations taken during the flaring and the low states, respectively, show a denser environment and a softer power-law index during the flaring state, implying that the pulsar wind interacted with the stronger stellar winds of the companion to produce the flares. These precursors would be crucial in studying the predicted giant outburst from this extreme γ -ray binary during the periastron passage in late 2017.},
doi = {10.3847/1538-4357/AA784E},
journal = {Astrophysical Journal},
number = 2,
volume = 843,
place = {United States},
year = {Mon Jul 10 00:00:00 EDT 2017},
month = {Mon Jul 10 00:00:00 EDT 2017}
}
  • PSR J2032+4127 is a radio-loud gamma-ray-emitting pulsar; it is orbiting around a high-mass Be type star with a very long orbital period of 25–50 years, and is approaching periastron, which will occur in late 2017/early 2018. This system comprises a young pulsar and a Be type star, which is similar to the so-called gamma-ray binary PSR B1259–63/LS2883. It is expected therefore that PSR J2032+4127 shows an enhancement of high-energy emission caused by the interaction between the pulsar wind and Be wind/disk around periastron. Ho et al. recently reported a rapid increase in the X-ray flux from this system. In thismore » paper, we also confirm a rapid increase in the X-ray flux along the orbit, while the GeV flux shows no significant change. We discuss the high-energy emissions from the shock caused by the pulsar wind and stellar wind interaction and examine the properties of the pulsar wind in this binary system. We argue that the rate of increase of the X-ray flux observed by Swift indicates (1) a variation of the momentum ratio of the two-wind interaction region along the orbit, or (2) an evolution of the magnetization parameter of the pulsar wind with the radial distance from the pulsar. We also discuss the pulsar wind/Be disk interaction at the periastron passage, and propose the possibility of formation of an accretion disk around the pulsar. We model high-energy emissions through the inverse-Compton scattering process of the cold-relativistic pulsar wind off soft photons from the accretion disk.« less
  • The radio and gamma-ray pulsar PSR J2032+4127 was recently found to be in a decades-long orbit with the Be star MT91 213, with the pulsar moving rapidly towards periastron. This binary shares many similar characteristics with the previously unique binary system PSR B1259-63/LS 2883. Here in this paper, we describe radio, X-ray, and optical monitoring of PSR J2032+4127/MT91 213. Our extended orbital phase coverage in radio, supplemented with Fermi LAT gamma-ray data, allows us to update and refine the orbital period to 45–50 yr and time of periastron passage to 2017 November. We analyse archival and recent Chandra and Swiftmore » observations and show that PSR J2032+4127/MT91 213 is now brighter in X-rays by a factor of ~70 since 2002 and ~20 since 2010. While the pulsar is still far from periastron, this increase in X-rays is possibly due to collisions between pulsar and Be star winds. Optical observations of the Hα emission line of the Be star suggest that the size of its circumstellar disc may be varying by ~2 over time-scales as short as 1–2 months. In conclusion, multiwavelength monitoring of PSR J2032+4127/MT91 213 will continue through periastron passage, and the system should present an interesting test case and comparison to PSR B1259-63/LS 2883.« less
  • On behalf of the International Astronomical Consortium for High Energy Calibration, we present results from the cross-calibration campaigns in 2012 on 3C 273 and in 2013 on PKS 2155-304 between the then active X-ray observatories Chandra , NuSTAR , Suzaku , Swift, and XMM-Newton . We compare measured fluxes between instrument pairs in two energy bands, 1–5 keV and 3–7 keV, and calculate an average cross-normalization constant for each energy range. We review known cross-calibration features and provide a series of tables and figures to be used for evaluating cross-normalization constants obtained from other observations with the above mentioned observatories.
  • PSR J2032+4127 is a γ-ray and radio-emitting pulsar which has been regarded as a young luminous isolated neutron star. However, its recent spin-down rate has extraordinarily increased by a factor of 2. Here we present evidence that this is due to its motion as a member of a highly-eccentric binary system with an ~15–M⊙ Be star, MT91 213. Timing observations show that, not only are the positions of the two stars coincident within 0.4 arcsec, but timing models of binary motion of the pulsar fit the data much better than a model of a young isolated pulsar. MT91 213, andmore » hence the pulsar, lie in the Cyg OB2 stellar association, which is at a distance of only 1.4–1.7 kpc. The pulsar is currently on the near side of, and accelerating towards, the Be star, with an orbital period of 20–30 yr. Finally, the next periastron is well constrained to occur in early 2018, providing an opportunity to observe enhanced high-energy emission as seen in other Be-star binary systems.« less