<i>ASCA</i>Observations of GRO J1744−28

Nishiuchi, Mamiko; Koyama, K.; Maeda, Yoshitomo; Asai, K.; Dotani, Tadayasu; Inoue, Hajime; Mitsuda, Kazuhisa; Nagase, F.; Ueda, Yoshihiro; Kouveliotou, C.

doi:10.1086/307165

Cited by 31 publications

(46 citation statements)

References 22 publications

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“…Its flaring characteristics, consisting of flare-dip pairs, are reminiscent of the type II bursts observed in the bursting pulsar GRO J1744-28 (Nishiuchi et al 1999) or in the Rapid Burster (Lewin et al 1996). But in these sources the energetics and timescales are very different, as the spectral dependence of their associated dips.…”

Section: Discussionmentioning

confidence: 99%

“…But in these sources the energetics and timescales are very different, as the spectral dependence of their associated dips. The source GRO J1744-28 could be more similar to XSS J1227, as the bursts (giant and small) do not show significant changes in spectral shape and show a good correlation between burst fluence and flux deficiency in the associated dips (Nishiuchi et al 1999). But during the post-flare dips, GRO J1744-28 shows no spectral changes and the burst fluence is related to the time when the source is in the persistent quiescent state.…”

Section: Discussionmentioning

confidence: 99%

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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

100

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: 99%

Section: Discussionmentioning

confidence: 99%

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

Martino¹,

Falanga²,

Bonnet‐Bidaud

et al. 2010

A&A

100

125

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“…(1) ASM (this paper), (2) Sazonov et al (1997), (3) Tanaka (1992), (4) Nakamura et al (1989), (5) Kitamoto et al (1992), (6) Watson et al (1978), (7) Tsunemi et al (1989). c Reference(s) for the distance: (i) van Paradijs & White (1995), (ii) Mirabel & Rodriguez (1994), (iii) Bradshaw et al (1999), (iv) Orosz & Kuulkers (1999), (v) Cowley et al (1979), (vi) Smale (1998), (vii) Penninx (1989), (viii) Wachter & Margon (1996), (ix) Christian & Swank (1997), (x) Ebisuzaki et al (1984), (xi) Predehl et al (2000), (xii) Nishiuchi et al (1999), (xiii) Orosz et al (2000), (xiv) King (1993), (xv) Nakamura et al (1989), (xvi) Greiner et al (1994), (xvii) Orosz et al (1996), (xviii) Barret et al (1996), (xix) Orosz et al (2002), (xx) Martin et al (1995), (xxi) Chevalier & Ilovaisky (1990). d Assuming a distance of 50 kpc for LMC and 60 kpc for SMC.…”

Section: Rxte All-sky Monitor Datamentioning

confidence: 99%

The Milky Way in X-rays for an outside observer

Grimm

Gilfanov

Sunyaev

2002

A&A

377

499

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Abstract. We study the Log(N)-Log(S ) and X-ray luminosity function in the 2-10 keV energy band, and the spatial (3-D) distribution of bright, L X ≥ 10 34 −10 35 erg s −1 , X-ray binaries in the Milky Way. In agreement with theoretical expectations and earlier results we found significant differences between the spatial distributions of low (LMXB) and high (HMXB) mass X-ray binaries. The volume density of LMXB sources peaks strongly at the Galactic Bulge whereas HMXBs tend to avoid the inner ∼3−4 kpc of the Galaxy. In addition HMXBs are more concentrated towards the Galactic Plane (scale heights of ≈150 and ≈410 pc for HMXB and LMXB correspondingly) and show clear signatures of the spiral structure in their spatial distribution. The Log(N)-Log(S ) distributions and the X-ray luminosity functions are also noticeably different. LMXB sources have a flatter Log(N)-Log(S ) distribution and luminosity function. The integrated 2-10 keV luminosities of all X-ray binaries in the Galaxy, averaged over 1996-2000, are ∼2−3 × 10 39 (LMXB) and ∼2−3 × 10 38 (HMXB) erg s −1 . Normalised to the stellar mass and the star formation rate, respectively, these correspond to ∼5 × 10 28 erg s −1 M −1 for LMXBs and ∼5 × 10 37 erg s −1 /(M yr −1 ) for HMXBs. Due to the shallow slopes of the luminosity functions the integrated emission of X-ray binaries is dominated by the ∼5-10 most luminous sources which determine the appearance of the Milky Way in the standard X-ray band for an outside observer. In particular variability of individual sources or an outburst of a bright transient source can increase the integrated luminosity of the Milky Way by as much as a factor of ∼2. Although the average LMXB luminosity function shows a break near the Eddington luminosity for a 1.4 M neutron star, at least 12 sources showed episodes of super-Eddington luminosity during ASM observations. We provide the maps of distribution of X-ray binaries in the Milky Way in various projections, which can be compared to images of nearby galaxies taken by CHANDRA and XMM-Newton.

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“…However in these sources the energetics and timescales are much different as well as the spectral dependence of their associated dips. GRO J1744-28 could be more similar to XSS J12270-4859 , as the bursts (giant and small) do not show significant changes in spectral shape and show a good correlation between burst fluence and flux deficiency in the associated dips [16]. However during the post-flare dips, GRO J1744-28 shows no spectral changes and the burst fluence is related to the time when the source is in the persistent quiescent state.…”

Section: The Lmxb Nature Of Xss J12270-4859mentioning

confidence: 98%

“…The present analysis therefore favours XSS J12270-4859 as a peculiar, low-luminosity LMXB. Its flaring characteristics, consisting of flare-dip pairs are reminiscent of the type II bursts observed in the bursting pulsar GRO J1744-28 [16] or in the Rapid Burster [13]. However in these sources the energetics and timescales are much different as well as the spectral dependence of their associated dips.…”

Section: The Lmxb Nature Of Xss J12270-4859mentioning

confidence: 99%

XSS J12270-4859 the first low mass X-ray binary gamma ray source system?

Falanga¹,

Martino²,

Bonnet‐Bidaud³

et al. 2011

Proceedings of 8th INTEGRAL Workshop “The Restless Gamma-Ray Universe” — PoS(INTEGRAL 2010)

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XSS J12270-4859 is an enigmatic X-ray source. While it was first classified as a possible magnetic Cataclysmic Variable (CV), our recent follow-up X-ray study with XMM-Newton, RXTE, and INTEGRAL has revealed a peculiar highly variable source. This source was later classified as a low mass X-ray binary (LMXB) and not as first suggested to be a CV. 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 UV range whilst 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. We found that XSS J12270-4859 is positionally compatible with the high energy Fermi/LAT source 1FGL J1227.9-4852 which is significant up to 10 GeV. The X-and Gamma-ray spectra suggest a continuum peaking around 1-100 MeV, which strengthens the association of the two sources. From our optical and near-IR photometry we could also detect a 4.32 hr periodicity, likely related to the binary orbit. This source could be the first gamma-ray binary of LMXB nature. 8th INTEGRAL Workshop "The Restless Gamma-ray Universe"

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ASCAObservations of GRO J1744−28

Cited by 31 publications

References 22 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

The Milky Way in X-rays for an outside observer

XSS J12270-4859 the first low mass X-ray binary gamma ray source system?

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