Understanding the LMXB X2127+119 in M 15

Ioannou, Z.; Zyl, L. van; Naylor, T.; Charles, P. A.; Margon, B.; Koch-Miramond, L.; Ilovaisky, S. A.

doi:10.1051/0004-6361:20021578

Cited by 14 publications

(24 citation statements)

References 23 publications

(29 reference statements)

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“…and velocities similar to ours have already been detected in other LMXBs (see, e.g., Ioannou et al 2003 andCostantini et al 2012). However, outflowing gas is more often observed at a higher ionization state (see, e.g., Miller et al 2006).…”

Section: Outflows With Intermediate Ionization States (Eg O Ii-iv)supporting

confidence: 88%

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Unveiling the environment surrounding low-mass X-ray binary SAX J1808.4–3658

Pinto

Costantini

Fabian

et al. 2014

A&A

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Context. Low-mass X-ray binaries (LMXBs) are a natural workbench to study accretion disk phenomena and optimal background sources to measure elemental abundances in the interstellar medium (ISM). In high-resolution XMM-Newton spectra, the LMXB SAX J1808.4−3658 in the past showed a neon column density significantly higher than expected given its small distance, presumably due to additional absorption from a neon-rich circumstellar medium (CSM). Aims. It is possible to detect intrinsic absorption from the CSM by evidence of Keplerian motions or outflows. For this purpose, we analyze a recent, deep (100 ks long), high-resolution Chandra/LETGS spectrum of SAX J1808.4−3658 in combination with archival data. Methods. We estimated the column densities of the different absorbers through the study of their absorption lines. We used both empirical and physical models involving photo-and collisional-ionization to determine the nature of the absorbers. Results. The abundances of the cold interstellar gas match the solar values as expected given the proximity of the X-ray source. For the first time in this source, we detected neon and oxygen blueshifted absorption lines, which can be well modeled with outflowing photoionized gas. The wind is neon rich (Ne/O 3) and may originate from processed, ionized gas near the accretion disk or its corona. The kinematics (v = 500−1000 km s −1 ) are indeed similar to those seen in other accretion disks. We also discovered a system of emission lines with very high Doppler velocities (v ∼ 24 000 km s −1 ) originating presumably closer to the compact object. Additional observations and UV coverage are needed to accurately determine the abundances and the ionization structure of the wind.

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Section: Outflows With Intermediate Ionization States (Eg O Ii-iv)supporting

confidence: 88%

“…Costantini et al (2012) found an absorption line system in the RGS spectrum of the LMXB 4U1820-30, which may also be described as a ∼1200 km s −1 outflow. Ioannou et al (2003) found evidence of a ∼1500 km s −1 C iv outflow in the Hubble Space Telescope (HST) UV spectrum of the LMXB X2127+119.…”

Section: Introductionmentioning

confidence: 99%

Unveiling the environment surrounding low-mass X-ray binary SAX J1808.4–3658

Pinto

Costantini

Fabian

et al. 2014

A&A

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“…Ultraviolet lines with strong P Cygni profiles indicate extensive mass loss. An analysis of the eclipse timing puts a rough upper limit on the period change of 0.01 d in 22 yr (Naylor et al 1992;Ioannou et al 2003). An extreme ultraviolet flux has been detected from M15.…”

Section: Notes On Individual Sourcesmentioning

confidence: 99%

Globular cluster X-ray sources

Verbunt

Lewin

2006

Compact Stellar X-Ray Sources

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Two new bright X-ray sources in globular clusters, and many less luminous ones in globular clusters and in old open clusters, have been discovered with ROSAT. Accurate positions obtained with ROSAT help identification with optical objects, which however is still very incomplete in globular clusters. One dim globular cluster source has been identified with a recycled radio pulsar; several others may be cataclysmic variables. The four brightest X-ray sources identified in the old open cluster M 67 are puzzling, as we do not understand why they emit X-rays. In comparison with the two old open clusters studied so far, globular clusters are remarkably underluminous in X-rays. FirstI am grateful to the organizers of this meeting for the opportunity to contribute to this celebration of the 65 th birthday of Joachim Trümper. During my years (1985)(1986)(1987)(1988)(1989) at the Max Planck Institut für extraterrestrische Physik, I have always felt very much at home, as if an 'honorary German', and I thank Joachim and my other colleagues for this. I was impressed with the width and depth of Joachim Trümper's interests, and thoroughly enjoyed my many discussions with him.The deadline for the first Announcement of Opportunity for observing with ROSAT was on a Sunday evening, at midnight (in checking the date, I find it was on my birthday!). Joachim Trümper was in his office that night, to sign proposals until just before the deadline, or almost, as 11 copies needed to be made for submission. Some of the proposals he signed that night contributed to the results discussed in this review.

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“…We timed the observations to correspond to phases ∼0.7 to ∼1.2 of the binary orbit (calculated according to the latest ephemeris by Ioannou et al 2003), in order to follow the behaviour of the lines through eclipse. In addition, with the luminous inner accretion disc obscured during eclipse, we hoped this would provide an opportunity to reveal the spectrum of the companion star.…”

Section: Observationsmentioning

confidence: 99%

“…by Homer & Charles 1998;Ioannou et al 2002Ioannou et al , 2003 to be a neutron star: no globular cluster X-ray binary is known to contain a black hole, and neutron stars are abundant in globular clusters (Hut et al 1991). The system has an orbital period of 17.1 h, which makes it unlikely that the companion star is on the main sequence (at an orbital period of 17.1 h a main-sequence donor star would not fill its Roche lobe).…”

Section: Introductionmentioning

confidence: 99%

A new mass-ratio for the X-ray binary X2127+119 in M 15?

Zyl

Ioannou

Charles

et al. 2004

A&A

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Abstract. The luminous low-mass X-ray binary X2127+119 in the core of the globular cluster M 15 (NGC 7078), which has an orbital period of 17 hours, has long been assumed to contain a donor star evolving off the main sequence, with a mass of 0.8 M (the main-sequence turn-off mass for M 15). We present orbital-phase-resolved spectroscopy of X2127+119 in the Hα and He  λ6678 spectral region, obtained with the Hubble Space Telescope. We show that these data are incompatible with the assumed masses of X2127+119's component stars. The continuum eclipse is too shallow, indicating that much of the accretion disc remains visible during eclipse, and therefore that the size of the donor star relative to the disc is much smaller in this highinclination system than the assumed mass-ratio allows. Furthermore, the flux of X2127+119's He  λ6678 emission, which has a velocity that implies an association with the stream-disc impact region, remains unchanged through eclipse, implying that material from the impact region is always visible. This should not be possible if the previously-assumed mass ratio is correct. In addition, we do not detect any spectral features from the donor star, which is unexpected for a 0.8-M sub-giant in a system with a 17-h period.

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Understanding the LMXB X2127+119 in M 15

Cited by 14 publications

References 23 publications

Unveiling the environment surrounding low-mass X-ray binary SAX J1808.4–3658

Unveiling the environment surrounding low-mass X-ray binary SAX J1808.4–3658

Globular cluster X-ray sources

A new mass-ratio for the X-ray binary X2127+119 in M 15?

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