Abstract
It is generally believed that magnetic fields of some neutron stars, the so-called magnetars, are enormously strong, up to 1014-10 15 G. Recent investigations have shown that the atmospheres of magnetars are possibly composed of helium. We calculate the structure and bound-bound radiative transitions of the He+ ion in superstrong fields, including the effects caused by the coupling of the ion's internal degrees of freedom to its center-of-mass motion. We show that He+ in superstrong magnetic fields can produce spectral lines with energies of up to ≈3 keV, and it may be responsible for absorption features detected recently in the soft X-ray spectra of several radio-quiet isolated neutron stars. Quantization of the ion's motion across a magnetic field results in a fine structure of spectral lines, with a typical spacing of tens of electron volts in magnetar-scale fields. It also gives rise to ion cyclotron transitions, whose energies and oscillator strengths depend on the state of the bound ion. The bound-ion cyclotron lines of He can be observed in the UV-optical range at B ≲ 1013 G, and they get into the soft X-ray range at B ≳ 1014 G.
| Original language | English (US) |
|---|---|
| Pages (from-to) | L61-L64 |
| Journal | Astrophysical Journal |
| Volume | 635 |
| Issue number | 1 II |
| DOIs | |
| State | Published - Dec 10 2005 |
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All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
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Once-ionized helium in superstrong magnetic fields. / Pavlov, George G.; Bezchastnov, Victor G.
In: Astrophysical Journal, Vol. 635, No. 1 II, 10.12.2005, p. L61-L64.Research output: Contribution to journal › Article
TY - JOUR
T1 - Once-ionized helium in superstrong magnetic fields
AU - Pavlov, George G.
AU - Bezchastnov, Victor G.
PY - 2005/12/10
Y1 - 2005/12/10
N2 - It is generally believed that magnetic fields of some neutron stars, the so-called magnetars, are enormously strong, up to 1014-10 15 G. Recent investigations have shown that the atmospheres of magnetars are possibly composed of helium. We calculate the structure and bound-bound radiative transitions of the He+ ion in superstrong fields, including the effects caused by the coupling of the ion's internal degrees of freedom to its center-of-mass motion. We show that He+ in superstrong magnetic fields can produce spectral lines with energies of up to ≈3 keV, and it may be responsible for absorption features detected recently in the soft X-ray spectra of several radio-quiet isolated neutron stars. Quantization of the ion's motion across a magnetic field results in a fine structure of spectral lines, with a typical spacing of tens of electron volts in magnetar-scale fields. It also gives rise to ion cyclotron transitions, whose energies and oscillator strengths depend on the state of the bound ion. The bound-ion cyclotron lines of He can be observed in the UV-optical range at B ≲ 1013 G, and they get into the soft X-ray range at B ≳ 1014 G.
AB - It is generally believed that magnetic fields of some neutron stars, the so-called magnetars, are enormously strong, up to 1014-10 15 G. Recent investigations have shown that the atmospheres of magnetars are possibly composed of helium. We calculate the structure and bound-bound radiative transitions of the He+ ion in superstrong fields, including the effects caused by the coupling of the ion's internal degrees of freedom to its center-of-mass motion. We show that He+ in superstrong magnetic fields can produce spectral lines with energies of up to ≈3 keV, and it may be responsible for absorption features detected recently in the soft X-ray spectra of several radio-quiet isolated neutron stars. Quantization of the ion's motion across a magnetic field results in a fine structure of spectral lines, with a typical spacing of tens of electron volts in magnetar-scale fields. It also gives rise to ion cyclotron transitions, whose energies and oscillator strengths depend on the state of the bound ion. The bound-ion cyclotron lines of He can be observed in the UV-optical range at B ≲ 1013 G, and they get into the soft X-ray range at B ≳ 1014 G.
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U2 - 10.1086/499270
DO - 10.1086/499270
M3 - Article
AN - SCOPUS:30544442770
VL - 635
SP - L61-L64
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1 II
ER -