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D. K. Galloway and L. Keek
directly motivating future experimental efforts. Thermonuclear burst physics has
been identified as a substantial priority for future nuclear physics experiments [4].
New observations are continually being sought, with the available fleet of longduration X-ray missions in addition to a handful of recently-launched instruments.
The current prospects for detection of new examples of burst oscillations appear
excellent, with the 2015 launch of India’s ASTROSAT mission, featuring a large-area
proportional counter with similar capabilities to RXTE’s PCA. Early observations
of 4U 1728−34 have detected high-frequency variability as seen earlier with RXTE
[189]. The 2017 deployment of the NICER instrument to the International Space
Station offered another avenue for detection of high-frequency variability, and the
“first-light” observations have detected burst oscillations in 4U 1608−52. 9
These new data also offer the prospect of new insights, particularly where the
observational capabilities exceed those to date. In particular, there are exciting
prospects of more detailed burst timing and spectral information from recentlylaunched large-area instruments including NICER and LAXPC, aboard ASTROSAT;
and in the more distant future, eXTP and Strobe-X. The data from these instruments
may more clearly distinguish the reflection spectrum, and perhaps also finally realise
the promise of burst oscillations for precisely constraining neutron star mass and
radius.
Acknowledgments The authors are grateful for helpful comments from Y. Cavecchi, M.C. Miller,
and H. Schatz. This work was supported in part by the National Science Foundation under Grant
No. PHY-1430152 (JINA Center for the Evolution of the Elements). The authors are grateful for
support received as part of the International Team on Nuclear Reactions in Superdense Matter by
the International Space Science Institute in Bern, Switzerland.
References
1. M.A. Alpar, A.F. Cheng, M.A. Ruderman, J. Shaham, A new class of radio pulsars. Nature
300, 728–730 (1982)
2. D. Altamirano, M. van der Klis, R. Wijnands, A. Cumming, Millihertz oscillation frequency
drift predicts the occurrence of type I X-ray bursts. Astrophys. J. Lett. 673, L35–L38 (2008)
3. D. Altamirano, L. Keek, A. Cumming, G.R. Sivakoff, C.O. Heinke, R. Wijnands, N. Degenaar, J. Homan, D. Pooley, A superburst candidate in EXO 1745-248 as a challenge to
thermonuclear ignition models. Mon. Not. R. Astron. Soc. 426, 927–934 (2012)
4. A. Arcones, D.W. Bardayan, T.C. Beers, L.A. Berstein, J.C. Blackmon, B. Messer, B.A.
Brown, E.F. Brown, C.R. Brune, A.E. Champagne, A. Chieffi, A.J. Couture, P. Danielewicz,
R. Diehl, M. El-Eid, J. Escher, B.D. Fields, C. Fröhlich, F. Herwig, W.R. Hix, C. Iliadis, W.G.
Lynch, G.C. McLaughlin, B.S. Meyer, A. Mezzacappa, F. Nunes, B.W. O’Shea, M. Prakash,
B. Pritychenko, S. Reddy, E. Rehm, G. Rogachev, R.E. Rutledge, H. Schatz, M.S. Smith, I.H.
Stairs, A.W. Steiner, T.E. Strohmayer, F.X. Timmes, D.M. Townsley, M. Wiescher, R.G.T.
Zegers, M. Zingale, White paper on nuclear astrophysics. ArXiv e-prints, March 2016
9 http://www.nasa.gov/press-release/goddard/2017/nasa-neutron-star-mission-begins-scienceoperations.
D. K. Galloway and L. Keek
directly motivating future experimental efforts. Thermonuclear burst physics has
been identified as a substantial priority for future nuclear physics experiments [4].
New observations are continually being sought, with the available fleet of longduration X-ray missions in addition to a handful of recently-launched instruments.
The current prospects for detection of new examples of burst oscillations appear
excellent, with the 2015 launch of India’s ASTROSAT mission, featuring a large-area
proportional counter with similar capabilities to RXTE’s PCA. Early observations
of 4U 1728−34 have detected high-frequency variability as seen earlier with RXTE
[189]. The 2017 deployment of the NICER instrument to the International Space
Station offered another avenue for detection of high-frequency variability, and the
“first-light” observations have detected burst oscillations in 4U 1608−52. 9
These new data also offer the prospect of new insights, particularly where the
observational capabilities exceed those to date. In particular, there are exciting
prospects of more detailed burst timing and spectral information from recentlylaunched large-area instruments including NICER and LAXPC, aboard ASTROSAT;
and in the more distant future, eXTP and Strobe-X. The data from these instruments
may more clearly distinguish the reflection spectrum, and perhaps also finally realise
the promise of burst oscillations for precisely constraining neutron star mass and
radius.
Acknowledgments The authors are grateful for helpful comments from Y. Cavecchi, M.C. Miller,
and H. Schatz. This work was supported in part by the National Science Foundation under Grant
No. PHY-1430152 (JINA Center for the Evolution of the Elements). The authors are grateful for
support received as part of the International Team on Nuclear Reactions in Superdense Matter by
the International Space Science Institute in Bern, Switzerland.
References
1. M.A. Alpar, A.F. Cheng, M.A. Ruderman, J. Shaham, A new class of radio pulsars. Nature
300, 728–730 (1982)
2. D. Altamirano, M. van der Klis, R. Wijnands, A. Cumming, Millihertz oscillation frequency
drift predicts the occurrence of type I X-ray bursts. Astrophys. J. Lett. 673, L35–L38 (2008)
3. D. Altamirano, L. Keek, A. Cumming, G.R. Sivakoff, C.O. Heinke, R. Wijnands, N. Degenaar, J. Homan, D. Pooley, A superburst candidate in EXO 1745-248 as a challenge to
thermonuclear ignition models. Mon. Not. R. Astron. Soc. 426, 927–934 (2012)
4. A. Arcones, D.W. Bardayan, T.C. Beers, L.A. Berstein, J.C. Blackmon, B. Messer, B.A.
Brown, E.F. Brown, C.R. Brune, A.E. Champagne, A. Chieffi, A.J. Couture, P. Danielewicz,
R. Diehl, M. El-Eid, J. Escher, B.D. Fields, C. Fröhlich, F. Herwig, W.R. Hix, C. Iliadis, W.G.
Lynch, G.C. McLaughlin, B.S. Meyer, A. Mezzacappa, F. Nunes, B.W. O’Shea, M. Prakash,
B. Pritychenko, S. Reddy, E. Rehm, G. Rogachev, R.E. Rutledge, H. Schatz, M.S. Smith, I.H.
Stairs, A.W. Steiner, T.E. Strohmayer, F.X. Timmes, D.M. Townsley, M. Wiescher, R.G.T.
Zegers, M. Zingale, White paper on nuclear astrophysics. ArXiv e-prints, March 2016
9 http://www.nasa.gov/press-release/goddard/2017/nasa-neutron-star-mission-begins-scienceoperations.