Spectral variations of LMC X-3 observed with GINGA

Ebisawa, Ken; Makino, F.; Mitsuda, Kazuhisa; Belloni, T.; Cowley, A. P.; Schmidtke, P. C.; Treves, A.

doi:10.1086/172239

Cited by 100 publications

(98 citation statements)

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“…In fact our first observation was close but did not exactly correspond to a minimum. Our non-detection can be explained by the source being in a soft state without a strong high energy component similar to what we observe during the second LMC X-1 observation and to what was reported for the March 1988 Ginga observation (Ebisawa et al 1993). …”

Section: Lmc X-3supporting

confidence: 89%

“…5), indicating we are again measuring a soft state of the source. A similar behaviour, with large variations of the hard-X ray component independent of the soft component, has been observed in this source and in LMC X-3 using Ginga data (Ebisawa et al 1989(Ebisawa et al , 1993. This seems to indicate that there is a mechanism responsible for the variation of high-energy emission, which does not involve variations of the low-energy flux.…”

Section: Lmc X-1supporting

confidence: 84%

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An INTEGRAL hard X-ray survey of the Large Magellanic Cloud

Götz¹,

Mereghetti²,

Merlini

et al. 2006

A&A

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Two observation campaigns in 2003 and 2004 with the INTEGRAL satellite have provided the first sensitive survey of the Large Magellanic Cloud with an imaging instrument in the hard X-ray range (15 keV-10 MeV). The high energy flux and long-term variability of the black hole candidate LMC X-1 was measured for the first time without contamination by the nearby (∼25 ) young pulsar PSR B0540-69. We studied the accreting pulsar LMC X-4 by constraining the size of the hard X-ray emitting region (≤3 × 10 10 cm) from analysis of its eclipses and by measuring its spin period (13.497 ± 0.005 s) in the 20-40 keV band. As it was in a soft state during the first observation and possibly in an extremely low state in the second one, LMC X-3 was not detected. Thanks to the large field of view of the IBIS instrument, we could also study other sources falling serendipitously in the observed sky region around the LMC: the Galactic low mass X-ray binary EXO 0748-676, the accreting pulsar SMC X-1 in the Small Magellanic Cloud, and the Active Galactic Nucleus IRAS 04575-7537. In addition we discovered five new hard X-ray sources, two of which most likely belong to the LMC.

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Section: Lmc X-3supporting

confidence: 89%

Section: Lmc X-1supporting

confidence: 84%

An INTEGRAL hard X-ray survey of the Large Magellanic Cloud

Götz¹,

Mereghetti²,

Merlini

et al. 2006

A&A

View full text Add to dashboard Cite

show abstract

“…These results significantly reinforce the BH scenario of ULXs since the MCD model can explain the soft X-ray spectra of Galactic/Magellanic black hole binaries (BHBs) in the "soft (or high) state" (e.g., Makishima et al 1986;Ebisawa et al 1993;Dotani et al 1997;Kubota et al 1998;Feroci et al 1999;Paper I).…”

supporting

confidence: 60%

Discovery of Spectral Transitions from Two Ultraluminous Compact X-Ray Sources in IC 342

Kubota

Mizuno

Makishima

et al. 2001

The Astrophysical Journal

114

124

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Two ASCA observations were made of two ultraluminous compact X-ray sources (ULXs) in the spiral galaxy IC 342. In the 1993 observation, source 2 showed a 0.5-10 keV luminosity of ergs s (assuming a 39 Ϫ16 # 10 distance of 4.0 Mpc) and a hard power-law spectrum of photon index ∼1.4. As already reported, source 1 was ∼3 times brighter on that occasion and exhibited a soft spectrum represented by a multicolor disk model with an inner-disk temperature of ∼1.8 keV. The second observation, made in 2000 February, revealed that source 1 had made a transition into a hard spectral state, while source 2 made a transition into a soft spectral state. The ULXs are therefore inferred to exhibit two distinct spectral states, and they sometimes make transitions between them. These results significantly reinforce the scenario that describes ULXs as mass-accreting black holes.

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“…First, the inner disk radius for NGC 5194 source 9 decreases significantly from the first to the second observation. In a high/soft state of Galactic black hole candidates, R in derived by adopting the MCD model remains constant (e.g., Ebisawa et al 1993). The variation of R in in NGC 5194 source 9 suggests that an MCD interpretation is not appropriate for this object and that the parameters derived above may be unreliable.…”

Section: Supersoft Ulxsmentioning

confidence: 99%

The Luminous X‐Ray Source Population in M51 Observed withChandra

Terashima

Wilson

2004

ApJ

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We present the results of two Chandra observations (separated by 1 yr) of the population of X-ray sources in the spiral galaxy M51 (NGC 5194 and NGC 5195). One hundred and thirteen X-ray sources have been detected in an 8A4 Â 8A4 (20:4 Â 20:4 kpc) region, and 84 and 12 of them project within the disks of NGC 5194 and NGC 5195, respectively. Nine and 28 sources have luminosities exceeding 1 Â 10 39 ergs s À1 (ultraluminous X-ray sources or ULXs) and 1 Â 10 38 ergs s À1 in the 0.5-8 keV band, respectively, assuming that they are associated with M51. The number of ULXs is much higher than found in most normal spiral and elliptical galaxies. Most of the X-ray sources and all seven of the ULXs in NGC 5194 are located in, or close to, a spiral arm, suggesting a connection with recent star formation. The cumulative luminosity function of the X-ray sources in NGC 5194 with Lð0:5 8 keVÞ > 10 38 ergs s À1 is well described by a power law, N ½>L(0.5-8 keVÞ / L(0.5-8 keV) À with ¼ 0:91. The X-ray spectra of most of the detected sources are consistent with a power law with a photon index between 1 and 2, with a few sources showing harder or softer spectra. The spectra of most ULXs are consistent with both a power law and a multicolor disk blackbody (MCD) model, while a power-law model is preferable to an MCD model in two ULXs. One ULX (NGC 5194 source 69) shows drastic spectral steepening accompanied by a decline in luminosity by a factor of 3460 in the 2-10 keV band between the two observations. This source also exhibited a possible period of 2.1 hr in the 2000 observation. Another ULX (NGC 5194 source 26) shows strong emission lines from highly ionized species. The masses of the compact objects and mass accretion rates in ULXs and other X-ray sources are not well constrained by these observations. If we adopt an MCD interpretation, their MCD parameters imply that most of the X-ray sources are stellar mass ($5-10 M ) black holes accreting near or above the Eddington rate, although other possibilities (intermediate-mass black holes and relativistically beamed emission) cannot be excluded. The power-law sources may instead represent Comptonized disk or nonthermal emission. Two ULXs have very soft spectra; MCD models require kT % 0:1 keV. We discuss the possibility that this soft emission originates in an accretion disk around an intermediate-mass black hole. We also present a study of the nucleus of, and discrete sources (including two ULXs) in, the companion galaxy NGC 5195.

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Spectral variations of LMC X-3 observed with GINGA

Cited by 100 publications

References 0 publications

An INTEGRAL hard X-ray survey of the Large Magellanic Cloud

An INTEGRAL hard X-ray survey of the Large Magellanic Cloud

Discovery of Spectral Transitions from Two Ultraluminous Compact X-Ray Sources in IC 342

The Luminous X‐Ray Source Population in M51 Observed withChandra

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