The Extended Power Law as an Intrinsic Signature for a Black Hole

Titarchuk, L.; Zannias, T.

doi:10.1086/305157

Cited by 107 publications

(105 citation statements)

References 10 publications

Supporting

Mentioning

100

Contrasting

Order By: Relevance

“…Di Salvo et al 2000) or in a corona (Poutanen & Coppi 1998), or by the bulk motion of accreting material close to the NS (e.g. Titarchuk & Zannias 1998). Another scenario suggests synchrotron emission from a relativistic jet escaping from the system (Markoff et al 2001) and, in the second scenario, theory expects also that radio emission would be observed (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…They have been associated with either emission of Comptonization by a non-thermal medium (Poutanen & Coppi 1998) or bulk motion of accreting material close to the NS (e.g. Titarchuk & Zannias 1998, but see also Di Salvo et al 2000). We verified that such a feature is not due to the predominance of the EPICpn spectrum guiding the fit: by excluding the EPIC-pn spectrum and fitting simultaneously only the ISGRI, JEMX-1 and JEMX-2 data, we can still find evidence of this hard tail.…”

Section: Persistent Emissionmentioning

confidence: 99%

See 1 more Smart Citation

Broad-band spectral analysis of the accreting millisecond X-ray pulsar SAX J1748.9−2021

Pintore

Sanna

Salvo

et al. 2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

We analyzed a 115 ks XMM-Newton observation and the stacking of 8 days of INTE-GRAL observations, taken during the raise of the 2015 outburst of the accreting millisecond X-ray pulsar SAX J1748.9-2021. The source showed numerous type-I burst episodes during the XMM-Newton observation, and for this reason we studied separately the persistent and burst epochs. We described the persistent emission with a combination of two soft thermal components, a cold thermal Comptonization component (∼2 keV) and an additional hard X-ray emission described by a power-law (Γ ∼ 2.3). The continuum components can be associated with an accretion disc, the neutron star (NS) surface and a thermal Comptonization emission coming out of an optically thick plasma region, while the origin of the high energy tail is still under debate. In addition, a number of broad (σ = 0.1-0.4 keV) emission features likely associated to reflection processes have been observed in the XMM-Newton data. The estimated 1.0-50 keV unabsorbed luminosity of the source is ∼5×10 37 erg s −1 , about 25% of the Eddington limit assuming a 1.4 M NS. We suggest that the spectral properties of SAX J1748.9-2021 are consistent with a soft state, differently from many other accreting X-ray millisecond pulsars which are usually found in the hard state. Moreover, none of the observed type-I burst reached the Eddington luminosity. Assuming that the burst ignition and emission are produced above the whole NS surface, we estimate a neutron star radius of ∼ 7 − 8 km, consistent with previous results.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Persistent Emissionmentioning

confidence: 99%

Broad-band spectral analysis of the accreting millisecond X-ray pulsar SAX J1748.9−2021

Pintore

Sanna

Salvo

et al. 2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

show abstract

“…These can be explained as either being produced in a hybrid thermal/non thermal medium (Poutanen & Coppi 1998) or by the bulk motion of accreting material close to the NS (e.g. Titarchuk & Zannias 1998). An alternative scenario proposes a mechanisms of Comptonization of seed photons by relativistic, non thermal, electrons in an outflow (e.g.…”

Section: Discussionmentioning

confidence: 99%

Study of the reflection spectrum of the accreting neutron star GX 3+1 using XMM–Newton and INTEGRAL

Pintore

Salvo

Bozzo

et al. 2015

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Broad emission features of abundant chemical elements, such as Iron, are commonly seen in the X-ray spectra of accreting compact objects and their studies can provide useful information about the geometry of the accretion processes. In this work, we focus our attention on GX 3+1, a bright, persistent accreting low mass X-ray binary, classified as an atoll source. Its spectrum is well described by an accretion disc plus a stable comptonizing, optically thick corona which dominates the X-ray emission in the 0.3-20 keV energy band. In addition, four broad emission lines are found and we associate them with reflection of hard photons from the inner regions of the accretion disc where doppler and relativistic effects are important. We used self-consistent reflection models to fit the spectra of the 2010 XMM-Newton observation and the stacking of the whole datasets of 2010 INTEGRAL observations. We conclude that the spectra are consistent with reflection produced at ∼ 10 gravitational radii by an accretion disc with an ionization parameter of ξ ∼ 600 erg cm s −1 and viewed under an inclination angle of the system of ∼ 35°. Furthermore, we detected for the first time for GX 3+1, the presence of a powerlaw component dominant at energies higher than 20 keV, possibly associated with an optically thin component of non-thermal electrons.

show abstract

“…The hard energy tail, described with a steep power-law with photon index ∼2-3 without evidence of a high energy cutoff, could be produced, as proposed for Z-sources, either in a hybrid thermal/nonthermal model (Poutanen & Coppi 1998) or in a bulk motion of matter close to the neutron star (e.g. Titarchuk & Zannias 1998). The alternative mechanism proposed is the Comptonization of seed photons by high-velocity electron of a jet (e.g.…”

Section: Banana States and High Energy Tailmentioning

confidence: 93%

Broadband observations of the X-ray burster 4U1705-44 withBeppoSAX

Piraino

Santangelo

Mück

et al. 2016

A&A

View full text Add to dashboard Cite

Context. 4U 1705-44 is one of the most-studied type I X-ray burster and Atoll sources. This source represents a perfect candidate to test different models proposed to self-consistently track the physical changes occurring between different spectral states because it shows clear spectral state transitions. Aims. The broadband coverage, the sensitivity and energy resolution of the BeppoSAX satellite offers the opportunity to disentangle the components that form the total X-ray spectrum and to study their changes according to the spectral state. Methods. Using two BeppoSAX observations carried out in August and October 2000, respectively, for a total effective exposure time of ∼100 ks, we study the spectral evolution of the source from a soft to hard state. Energy spectra are selected according to the source position in the color-color diagram (CCD). Results. We succeeded in modeling the spectra of the source using a physical self-consistent scenario for both the island and banana branches (the double Comptonization scenario). The components observed are the soft Comptonization and hard Comptonization, the blackbody, and a reflection component with a broad iron line. When the source moves from the banana state to the island state, the parameters of the two Comptonization components change significantly and the blackbody component becomes too weak to be detected. Conclusions. We interpret the soft Comptonization component as emission from the hot plasma surrounding the neutron star, hard Comptonization as emission from the disk region, and the blackbody component as emission from the inner accretion disk. The broad feature in the iron line region is compatible with reflection from the inner accretion disk.

show abstract

The Extended Power Law as an Intrinsic Signature for a Black Hole

Cited by 107 publications

References 10 publications

Broad-band spectral analysis of the accreting millisecond X-ray pulsar SAX J1748.9−2021

Broad-band spectral analysis of the accreting millisecond X-ray pulsar SAX J1748.9−2021

Study of the reflection spectrum of the accreting neutron star GX 3+1 using XMM–Newton and INTEGRAL

Broadband observations of the X-ray burster 4U1705-44 withBeppoSAX

Contact Info

Product

Resources

About