1E 1740.7–2942: Temporal and spectral evolution from INTEGRAL and RXTE observations

Santo, M. Del; Bazzano, A.; Zdziarski, A. A.; Smith, David M.; Bezayiff, N.; Farinelli, R.; Cesare, G. De; Ubertini, P.; Bird, A. J.; Bel, M. Cadolle; Capitanio, Fiamma; Goldwurm, A.; Malizia, A.; Mirabel, I. F.; Natalucci, L.; Winkler, Christoph

doi:10.1051/0004-6361:20042058

Cited by 35 publications

(53 citation statements)

References 30 publications

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“…In our spectral analysis for 2003 and 2005, we found the presence of Compton reflection, which agrees with previous reports for 1E 1740.7−2942 spectra (e.g., Del Santo et al 2005). Our 2012 spectral modeling, however, found no evidence for such a component, which is also compatible with other results (e.g., Natalucci et al 2014).…”

Section: Discussionsupporting

confidence: 92%

“…For example, our measured temperatures are different from the ones reported by Del Santo et al (2005), but this is probably due to the fact that these authors have used the physical assumptions of the compPS model, which was not used here. Similarly, a different modeling was used by Bouchet et al (2009) and Reynolds & Miller (2010).…”

Section: Discussioncontrasting

confidence: 75%

“…Motivated by the evidence of Compton reflection found by some authors in 1E 1740.7−2942 (Del Santo et al 2005), and by the study of Natalucci et al (2014), which found no evidence of it, we also used the convolutive reflect component in our fits (Magdziarz & Zdziarski 1995). Presence of reflection is very common in the low/hard spectra of black hole binaries (see, e.g., Zdziarski et al 1999).…”

Section: Resultsmentioning

confidence: 99%

“…We have also made an attempt to fit our spectra with the compPS model (Poutanen & Svensson 1996) in XSPEC to check what has been tried before (Del Santo et al 2005). CompPS provides a numerical solution of the radiative transfer equation, and it comprises Compton reflection as one of its parameters.…”

Section: Resultsmentioning

confidence: 99%

“…The source was dubbed a microquasar after radio jets were observed (Mirabel et al 1992). The intense optical extinction toward the Galactic Center still prevents the identification of the counterpart of 1E 1740.7−2942 at optical and infrared wavelengths, despite all efforts (Del Santo et al 2005;Smith et al 2002;Martí et al 2000). ASCA (Sakano et al 1999) as well as Chandra (Gallo & Fender 2002) that were helpful in determining the column density of hydrogen (N H ).…”

Section: Introductionmentioning

confidence: 99%

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Confirming the thermal Comptonization model for black hole X-ray emission in the low-hard state

Castro¹,

D'Amico²,

Braga³

et al. 2014

A&A

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Hard X-ray spectra of black hole binaries in the low/hard state are well modeled by thermal Comptonization of soft seed photons by a corona-type region with kT ∼ 50 keV and optical depth around 1. Previous spectral studies of 1E 1740.7−2942, including both the soft and the hard X-ray bands, were always limited by gaps in the spectra or by a combination of observations with imaging and non-imaging instruments. In this study, we have used three rare nearly-simultaneous observations of 1E 1740.7−1942 by both XMM-Newton and INTEGRAL satellites to combine spectra from four different imaging instruments with no data gaps, and we successfully applied the Comptonization scenario to explain the broadband X-ray spectra of this source in the low/hard state. For two of the three observations, our analysis also shows that, models including Compton reflection can adequately fit the data, in agreement with previous reports. We show that the observations can also be modeled by a more detailed Comptonization scheme. Furthermore, we find the presence of an iron K-edge absorption feature in one occasion, which confirms what had been previously observed by Suzaku. Our broadband analysis of this limited sample shows a rich spectral variability in 1E 1740.7−2942 at the low/hard state, and we address the possible causes of these variations. More simultaneous soft/hard X-ray observations of this system and other black-hole binaries would be very helpful in constraining the Comptonization scenario and shedding more light on the physics of these systems.

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Section: Discussionsupporting

confidence: 92%

Section: Discussioncontrasting

confidence: 75%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Confirming the thermal Comptonization model for black hole X-ray emission in the low-hard state

Castro¹,

D'Amico²,

Braga³

et al. 2014

A&A

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show abstract

On the behavior of the black hole candidate 1E 1740.7‐2942's corona based on long‐term INTEGRAL database

et al. 2021

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One of the most straightforward ways to explain the hard X-ray spectra observed in X-ray binaries is to assume that comptonization of soft photons from the accretion disk is occurring. The region where this process takes place, called the corona, is characterized by only two parameters: its thermal energy kT and its optical depth τ. Hard X-ray spectra analysis is, thus, an imperative tool in diagnosing the behavior of these parameters. The lack of consistency in obtaining/analyzing long-term databases, however, may have been hindering this kind of characterization from being attained. With the aim of better understanding the corona behavior in the black hole candidate 1E 1740.7-2942, we performed a homogeneous analysis for a large hard X-ray data set from the ISGRI telescope on-board the INTEGRAL satellite. Results from modeling the spectra show that, for most of our sample, unsaturated thermal comptonization is the main mechanism responsible for the hard X-ray spectra observed in 1E 1740.7-2942. Moreover, such extensive database allowed us to produce what is probably the longest hard X-ray light curve of 1E 1740.7-2942 and whose units-due to recent findings regarding dynamical quantities of the system-could be expressed in % of Eddington's luminosity.

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Spectral behaviour of an INTEGRAL sample of black hole candidates: Initial results

Ubertini¹,

Bazzano²,

Capitanio³

et al. 2006

Advances in Space Research

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1E 1740.7–2942: Temporal and spectral evolution from INTEGRAL and RXTE observations

Cited by 35 publications

References 30 publications

Confirming the thermal Comptonization model for black hole X-ray emission in the low-hard state

Confirming the thermal Comptonization model for black hole X-ray emission in the low-hard state

On the behavior of the black hole candidate 1E 1740.7‐2942's corona based on long‐term INTEGRAL database

Spectral behaviour of an INTEGRAL sample of black hole candidates: Initial results

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