Unveiling the nature of <i>INTEGRAL</i> objects  through optical 
spectroscopy

Masetti, N.; Morelli, L.; Palazzi, E.; Galaz, Gaspar; Bassani, L.; Bazzano, A.; Bird, A. J.; Dean, A. J.; Israel, G. L.; Landi, R.; Malizia, A.; Minniti, D.; Schiavone, F.; Stephen, J. B.; Ubertini, P.; Walter, R.

doi:10.1051/0004-6361:20066055

Cited by 144 publications

(153 citation statements)

References 45 publications

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“…We also revised the optical spectrum presented in Masetti et al (2006) and confirm the equivalent widths of the major Balmer emission lines. We note however that due to the low spectral resolution, the He II (4686 Å) line is blended with C III (4650).…”

Section: Discussionmentioning

confidence: 62%

“…These were derived by comparing the photometry of the reference star HD 108433 in the target field. A comparison with the optical spectrum acquired by Masetti et al (2006) indicates that XSS J1227 was about at the same optical level. Furthermore from a comparison with J-band 2MASS magnitude (J = 15.73 mag), the source is found at a comparable level.…”

Section: The Optical and Near-ir Photometrymentioning

confidence: 85%

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The intriguing nature of the high-energy gamma ray source XSS J12270-4859

Martino¹,

Falanga²,

Bonnet‐Bidaud

et al. 2010

A&A

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125

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Context. The nature of the hard X-ray source XSS J12270-4859 is still unclear. It was claimed to be a possible magnetic cataclysmic variable of the Intermediate Polar type from its optical spectrum and a possible 860 s X-ray periodicity in RXTE data. However, recent observations do not support the latter variability, leaving this X-ray source still unclassified. Aims. To investigate its nature we present a broad-band X-ray and gamma ray study of this source based on a recent XMM-Newton observation and archival INTEGRAL and RXTE data. Using the Fermi/LAT 1-year point source catalogue, we tentatively associate XSS J12270-4859 with 1FGL J1227.9-4852, a source of high-energy gamma rays with emission up to 10 GeV. We further complement the study with UV photometry from XMM-Newton and ground-based optical and near-IR photometry. Methods. We have analysed both timing and spectral properties in the gamma rays, X-rays, UV and optical/near-IR bands of XSS J12270-4859. Results. The X-ray emission is highly variable, showing flares and intensity dips. The flares consist of flare-dip pairs. Flares are detected in both X-rays and the UV range, while the subsequent dips are present only in the X-ray band. Further aperiodic dipping behaviour is observed during X-ray quiescence, but not in the UV. The broad-band 0.2-100 keV X-ray/soft gamma ray spectrum is featureless and well described by a power law model with Γ = 1.7. The high-energy spectrum from 100 MeV to 10 GeV is represented by a power law index of 2.45. The luminosity ratio between 0.1-100 GeV and 0.2-100 keV is ∼0.8, indicating that the GeV emission is a significant component of the total energy output. Furthermore, the X-ray spectrum does not greatly change during flares, quiescence and the dips seen in quiescence. The X-ray spectrum however hardens during the post-flare dips, where a partial covering absorber is also required to fit the spectrum. Optical photometry acquired at different epochs reveals a period of 4.32 hr that could be ascribed to the binary orbital period. Near-IR, possibly ellipsoidal, variations are detected. Large amplitude variability on shorter (tens mins) timescales is found to be non-periodic. Conclusions. The observed variability at all wavelengths together with the spectral characteristics strongly favour a low-mass atypical low-luminosity X-ray binary and are against a magnetic cataclysmic variable nature. The association with a Fermi/LAT high-energy gamma ray source further strengths this interpretation.

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Section: Discussionmentioning

confidence: 62%

Section: The Optical and Near-ir Photometrymentioning

confidence: 85%

The intriguing nature of the high-energy gamma ray source XSS J12270-4859

Martino¹,

Falanga²,

Bonnet‐Bidaud

et al. 2010

A&A

Self Cite

125

View full text Add to dashboard Cite

show abstract

“…The lack of early-type signatures in the unobscured optical spectrum (Masetti et al 2006) indicates that the secondary is a late-type star. The flux changes in ∼100 s and the power-law spectrum point toward a LMXB nature of this source.…”

Section: Discussionmentioning

confidence: 99%

“…The distance to J12270 was estimated as ∼220 pc (Masetti et al 2006) assuming that the V -band flux is dominated by the secondary. However, the variability with a large amplitude of >1 mag in this band (Pretorius 2009) indicates that the emission from the accreting material accounts for a substantial fraction.…”

Section: Discussionmentioning

confidence: 99%

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Suzaku X-Ray Study of an Anomalous Source XSS J12270–4859

Saitou

Tsujimoto

Ebisawa

et al. 2009

Publications of the Astronomical Society of Japan

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We report the results of the Suzaku X-ray observation of XSS J12270-4859, one of the hard X-ray sources in the INTEGRAL catalogue. The object has been classified as an intermediate polar (IP) by optical spectra and a putative X-ray period of ∼860 s. With a 30 ks exposure of Suzaku, we obtained a well-exposed spectrum in the 0.2-70 keV band. We conclude against the previous IP classification based on the lack of Fe Kα emission features in the spectrum and the failure to confirm the previously reported X-ray period. Instead, the X-ray light curve is filled with exotic phenomena, including repetitive flares lasting ∼100 s, occasional dips with no apparent periodicities, spectral hardening after some flares, and bimodal changes pivoting between quiet and active phases. The rapid flux changes, the dips, and the power-law spectrum point toward the interpretation that this is a low-mass X-ray binary. Some temporal characteristics are similar to those in the Rapid Burster and GRO J1744-28, making XSS J12270-4859 a very rare object.

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Evolution of high‐mass X‐ray binaries in the small magellanic cloud

et al. 2019

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To understand the progenitor of rotation-powered pulsars, we compare them with accreting High-Mass X-ray binary pulsars, (hereafter X-ray pulsars), in the small magellanic cloud. The diagram of spin period vs. period derivative shows that isolated neutron stars could be evolved from X-ray pulsars. The pulsars with long spin period might spin up to 0.001-1 s. The binary orbit is disrupted by a third body in the universe, and the binaries are detached. Therefore, some of the pulsars become isolated neutron stars.

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Unveiling the nature of INTEGRAL objects through optical spectroscopy

Cited by 144 publications

References 45 publications

The intriguing nature of the high-energy gamma ray source XSS J12270-4859

The intriguing nature of the high-energy gamma ray source XSS J12270-4859

Suzaku X-Ray Study of an Anomalous Source XSS J12270–4859

Evolution of high‐mass X‐ray binaries in the small magellanic cloud

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