The Study of Variations of Cyclotron Resonant Scattering Features in GX 301-2 by using the INTEGRAL/IBIS

Yu Guangwen; Wang Wei

Astronomical Research and Technology > 2016 > 13(1): 11-23.

Yu Guangwen, Wang Wei. The Study of Variations of Cyclotron Resonant Scattering Features in GX 301-2 by using the INTEGRAL/IBIS[J]. Astronomical Research and Technology, 2016, 13(1): 11-23.

Citation:

Yu Guangwen, Wang Wei. The Study of Variations of Cyclotron Resonant Scattering Features in GX 301-2 by using the INTEGRAL/IBIS[J]. Astronomical Research and Technology, 2016, 13(1): 11-23.

Citation:

Yu Guangwen, Wang Wei. The Study of Variations of Cyclotron Resonant Scattering Features in GX 301-2 by using the INTEGRAL/IBIS[J]. Astronomical Research and Technology, 2016, 13(1): 11-23.

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The Study of Variations of Cyclotron Resonant Scattering Features in GX 301-2 by using the INTEGRAL/IBIS

Yu Guangwen^1,2,
Wang Wei^1, ,

1. National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China;
2. University of Chinese Academy of Sciences, Beijing 100049, China

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This work is based on observations of INTEGRAL,an ESA project with instrument and science data center funded by ESA member states.

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Received Date: March 31, 2015
Revised Date: April 25, 2015
Available Online: November 20, 2023

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Abstract

Abstract

With long-term hard X-ray monitoring,observations on high mass X-ray binary GX 301-2 from 2003-2011 performed by INTEGRAL/IBIS,we first systematically studied its spectral properties in different accreting luminosities and orbital phases.The cyclotron resonant scattering feature(CRSF) at energies from 35-47 keV was detected in the hard X-ray spectra,suggesting the magnetic field of 5×10¹² Gs.The variations of the CRSF show no relation to the X-ray luminosity while the line centroid energy of the CRSF has a positive correlation to the photon index and spectral cutoff energy,and there also exists a weak correlation between the absorption depth and cutoff energy.These relations support the idea that the spectral cutoff in accreting X-ray pulsars is strongly affected by the cyclotron resonant scattering.The correlation between the ratio of the line width to the centroid energy and absorption depth implies a tall cylindrical accreting column on the surface of the neutron star in GX 301-2.The explanation of the long spin period in GX 301-2 requires a strong surface magnetic field at least higher than 2×10¹⁴ Gs which is contradict with the measured value based on the cyclotron line energy.The line-forming region with a height at least larger than two neutron star radii is proposed to resolve the contradiction.This scenario is supported by the tall cylindrical accreting column on the neutron star surface in GX 301-2 according to the variation patterns of the CRSF.In addition,the possible evolution scenario of accreting magnetars like GX 301-2 is briefly discussed,and GX 301-2 would be an accreting magnetar in the equivalence phase.
- GX 301-2,
- X-rays binaries,
- Neutron,
- Magnetic fields

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References (37)

References

[1]	Bildsten L,Chakrabarty D,Chiu J,et al.Observations of accreting pulsars[J].The Astrophysical Journal Supplement,1997,113(2):367-408.
[2]	Parkes G E,Culhane J L,Mason K O,et al.A spectral study of Wray 977,the optical counterpart of the binary X-ray pulsar 4U 1223-62[J].Monthly Notices of the Royal Astronomical Society,1980,191(3):547-558.
[3]	Kaper L,Lamers H J G L M,Ruymaekers E,et al.Wray 977(GX 301-2):a hypergiant with pulsar companion[J].Astronomy and Astrophysics,1995,300:446-452.
[4]	Kaper L,van der Meer A,Najarro F.VLT/UVES spectroscopy of Wray 977,the hypergiant companion to the X-ray pulsar GX301-2[J].Astronomy and Astrophysics,2006,457(2):595-610.
[5]	Koh D T,Bildsten L,Chakrabarty D,et al.Rapid Spin-Up Episodes in the Wind-fed Accreting Pulsar GX 301-2[J].The Astrophysical Journal,1997,479(2):933-947.
[6]	Doroshenko V,Santangelo A,Suleimanov V,et al.Is there a highly magnetized neutron star in GX 301-2?[J].Astronomy and Astrophysics,2010,515:A10-A19.
[7]	White N E,Mason K O,Huckle H E,et al.Periodic modulation of three galactic X-ray sources[J].Astrophysical Journal,1976,209(1):L119-L124.
[8]	Evangelista Y,Feroci M,Costa E,et al.Temporal properties of GX 301-2 over a year-long observation with super AGILE[J].The Astrophysical Journal,2010,708(2):1663-1673.
[9]	Makishima K,Mihara T.Magnetic fields of neutron stars[C].Tokyo Japan:Frontiers Science Series,1992:23.
[10]	Orlandini M,dal Fiume D,Frontera F,et al.Beppo SAX observations of an orbital cycle of the X-ray binary pulsar GX 301-2[J].Advances in Space Research,2000,25(3-4):417-420.
[11]	Mészáros P.High Energy Radiation from Magnetized Neutron Stars[M].Chicago:University of Chicago Press,1992.
[12]	Kreykenbohm I,Wilms J,Coburn W,et al.The variable cyclotron line in GX 301-2[J].Astronomy and Astrophysics,2004,427(3):975-986.
[13]	La Barbera A,Segreto A,Sanangelo A,et al.A study of an orbital cycle of GX 301-2 observed by BeppoSAX[J].Astronomy and Astrophysics,2005,438(2):617-632.
[14]	Suchy S,Fürst F,Pottschmidt K,et al.Broadband spectroscopy using two Suzaku observations of the HMXB GX 301-2[J].The Astrophysical Journal,2012,745(2):124-135.
[15]	Li Jun,Wang Wei,Zhao Yongheng.Cyclotron resonance energies and orbital elements of accretion pulsar 4U 0115+63 during the giant outburst in 2008[J].Monthly Notices of the Royal Astronomical Society,2012,423(3):2854-2867.
[16]	Klochkov D,Doroshenko V,Santangelo A,et al.Outburst of GX 304-1 monitored with INTEGRAL:positive correlation between the cyclotron line energy and flux[J].Astronomy & Astrophysics,2012,542(4):L28-L31.
[17]	Vasco D,Klochkov D,Staubert R.Hercules X-1:the positive cyclotron line energy/luminosity correlation[J].Astronomy & Astrophysics,2011,532:A99-A104.
[18]	Ghosh P,Lamb F K.Accretion by rotating magnetic neutron stars.Ⅲ-accretion torques and period changes in pulsating X-ray sources[J].Astrophysical Journal,1979,234(15):296-316.
[19]	Urpin V,Konenkov D,Geppert U.Evolution of neutron stars in high-mass X-ray binaries[J].Monthly Notices of the Royal Astronomical Society,1998,99(1):73-77.
[20]	Wang Wei.Evidence for a magnetic neutron star in high-mass X-ray binary 4U 2206+54 with INTEGRAL/IBIS observations[J].Monthly Notices of the Royal Astronomical Society,2009,398(3):1428-1434.
[21]	Wang Wei.Spin and spectral variations of a peculiar high-mass X-ray binary 4U 2206+54[J].Monthly Notices of the Royal Astronomical Society,2013,432(2):954-966.
[22]	Wang Wei.Long-term hard X-ray monitoring of 2S 0114+65 with INTEGRAL/IBIS[J].Monthly Notices of the Royal Astronomical Society,2011,413(2):1083-1098.
[23]	Haberl F,Sturm R,Filipovic M D,et al.SXP 1062,a young Be X-ray binary pulsar with long spin period; Implications for the neutron star birth spin[J].Astronomy & Astrophysics,2012,537(1):L1-L5.
[24]	Winkler C,Courvoisier T J L,Di Cocco G,et al.The INTEGRAL mission[J].Astronomy and Astrophysics,2003,411(1):L1-L6.
[25]	Leburn F,Lerav J P,Lavocat P,et al.ISGRI:The INTEGRAL soft gamma-ray imager[J].Astronomy and Astrophysics,2003,411(1):L141-L148.
[26]	Goldwurm A,David P,Foschini L,et al.The INTEGRAL/IBIS scientific data analysis[J].Astronomy and Astrophysics,2003,411(1):L223-L229.
[27]	Mihara T,Makishima K,Ohashi T,et al.New observations of the cyclotron absorption feature in Hercules X-1[J].Nature,1990,346:250-252.
[28]	Makishima K,Mihara T,Nagase F,et al.Cyclotron resonance effects in two binary X-ray pulsars and the evolution of neutron star magnetic fields[J].The Astrophysical Journal,1999,525(2):978-994.
[29]	Kreykenbohm I,Coburn W,Wilms J,et al.Confirmation of two cyclotron lines in Vela X-1[J].Astronomy and Astrophysics,2002,395(1):129-140.
[30]	Coburn W,Heindl W A,Rothschild R E,et al.Magnetic fields of accreting X-ray pulsars with the Rossi X-ray timing explorer[J].The Astrophysical Journal,2002,580(1):394-412.
[31]	Araya R A,Harding A K.Cyclotron line features from near-critical magnetic fields:the effect of optical depth and plasma geometry[J].The Astrophysical Journal,1999,517(1):334-354.
[32]	Nishimura O.Superposition of cyclotron lines in accreting X-ray pulsars.I.long spin period[J].The Astrophysical Journal,2011,730(2):106-116.
[33]	Meszaros P,Nagel W.X-ray pulsar models.I-angle-dependent cyclotron line formation and comptonization[J].The Astrophysical Journal,1985,298:147-160.
[34]	Isenberg M,Lamb D Q,Wang J C L.Effects of the geometry of the line-forming region on the properties of cyclotron resonant scattering lines[J].The Astrophysical Journal,1998,05(2):688-714.
[35]	Leahy D A.The RXTE/ASM X-ray light curve of GX301-2[J].Astronomy and Astrophysics,2002,391(1):219-224.
[36]	Swank J H,Becker R H,Boldt E A,et al.Variations in the spectra and pulse period of GX 301-2[J].The Astrophysical Journal,1976,209:L57-L60.
[37]	Basko M M,Sunyaev R A.The limiting luminosity of accreting neutron stars with magnetic fields[J].Monthly Notices of the Royal Astronomical Society,1976,175(2):395-417.