New INTEGRAL sources and TeV emission

Walter, R.

doi:10.1007/s10509-007-9477-9

Cited by 11 publications

(8 citation statements)

References 25 publications

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“…These numbers confirm once more the effectiveness of this method of catalogue cross-correlation plus optical spectroscopy followup in revealing the AGN and CV nature of a large number of unidentified INTEGRAL sources, while it may introduces a bias against detecting X-ray binaries: this is however quite understandable, given that, as INTEGRAL is sensitive to the hard X-ray radiation, it can easily detect sources deeply embedded in the Galactic Plane dust and therefore heavily obscured (as already stressed by, e.g., Walter 2007). Thus, we foresee that the use of NIR spectroscopy followup will reveal a larger number of absorbed X-ray binaries.…”

Section: Statistical Considerationsmentioning

confidence: 97%

“…The IBIS survey allowed pinpointing, for the first time, extragalactic sources in the so-called 'Zone of Avoidance', which hampers observations in soft X-rays along the Galactic plane due to the presence of gas and dust. Moreover, this survey is expanding our knowledge about Galactic X-ray binaries, by showing the existence of a new class of heavily absorbed supergiant massive X-ray binaries (e.g., Walter et al 2004), by allowing the discovery of supergiant fast X-ray transients (e.g., Sguera et al 2006;Leyder et al 2007), by doubling the number of known high-mass X-ray binaries (HMXBs; see Walter 2007), and by detecting a number of new magnetic cataclysmic variables (CVs; e.g., Barlow et al 2006;Bonnet-Bidaud et al 2007).…”

Section: Introductionmentioning

confidence: 99%

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Unveiling the nature ofINTEGRALobjects through optical spectroscopy

Masetti¹,

Mason

Morelli

et al. 2008

A&A

112

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Using 8 telescopes in the northern and southern hemispheres, plus archival data from two on-line sky surveys, we performed a systematic optical spectroscopic study of 39 putative counterparts of unidentified or poorly studied INTEGRAL sources in order to determine or at least better assess their nature. This was implemented within the framework of our campaign to reveal the nature of newly-discovered and/or unidentified sources detected by INTEGRAL. Our results show that 29 of these objects are active galactic nuclei (13 of which are of Seyfert 1 type, 15 are Seyfert 2 galaxies and one is possibly a BL Lac object) with redshifts between 0.011 and 0.316, 7 are X-ray binaries (5 with high-mass companions and 2 with low-mass secondaries), one is a magnetic cataclysmic variable, one is a symbiotic star and one is possibly an active star. Thus, the large majority (74%) of the identifications in this sample belongs to the AGN class. When possible, the main physical parameters for these hard X-ray sources were also computed using the multiwavelength information available in the literature. These identifications further underscore the importance of INTEGRAL in studying the hard X-ray spectra of all classes of X-ray emitting objects, and the effectiveness of a strategy of multi-catalogue cross-correlation plus optical spectroscopy to securely pinpoint the actual nature of still unidentified hard X-ray sources.

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Section: Statistical Considerationsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Unveiling the nature ofINTEGRALobjects through optical spectroscopy

Masetti¹,

Mason

Morelli

et al. 2008

A&A

112

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“…Is there any room in this scenario for MeV-GeV γ -ray flares or extended TeV emission? Walter (2007) suggests that protons could be accelerated by multiple scattering of Alfvén waves in or close to the accretion column and then interact with material at the magnetospheric radius producing γ -rays through inelastic pp collisions and the subsequent decays. He estimates maximum Lorentz factors for the protons of ∼10 8 , i.e., energies of ∼10 17 eV.…”

Section: Origin Of Mev Flares or Extended Tevmentioning

confidence: 99%

DISSECTING THE REGION OF 3EG J1837-0423 AND HESS J1841-055 WITHINTEGRAL

Sguera

Romero

Bazzano

et al. 2009

ApJ

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3EG J1837-0423 and HESS J1841-055 are two unidentified and peculiar high-energy sources located in the same region of the sky, separated by ∼1.4 deg. Specifically, 3EG J1837-0423 is a transient MeV object detected by EGRET only once during flaring activity that lasted a few days while HESS J1841-055 is a highly extended TeV source. We attempted to match the high-energy emission from the unidentified sources 3EG J1837-0423 and HESS J1841-055 with X-rays (4-20 keV) and soft γ -rays (20-100 keV) candidate counterparts detected through deep International Gamma-Ray Astrophysics Laboratory observations of the sky region. As a result we propose the Supergiant Fast X-ray Transient (SFXT) AX J1841.0-0536 as a possible candidate counterpart of 3EG J1837-0423, based on spatial proximity and transient behavior. Alternatively, AX J1841.0-0536 could be responsible for at least a fraction of the entire TeV emission from the extended source HESS J1841-055, based on a striking spatial correlation. In either case, the proposed association is also supported from an energetic standpoint by a theoretical scenario where AX J1841.0-0536 is a low magnetized pulsar which, due to accretion of massive clumps from the supergiant companion donor star, undergoes sporadic changes to transient Atoll-states where a magnetic tower can produce transient jets and as a consequence high-energy emission. In either case (by association with 3EG J1837-0423 or alternatively with HESS J1841-055), AX J1841.0-0536 might be the prototype of a new class of Galactic transient MeV/TeV emitters.

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“…Since 2005, SFTXs have been monitored regularly in the X-rays and a relatively large effort was devoted to perform observations of these sources in different energy domains, spanning from the far IR to γ-rays (Walter, 2007) and up to the very high energies (∼GeV; Sguera et al, 2009Sguera et al, , 2011. It was soon understood that all SFXT systems were hosting a compact object accreting from the wind of a massive companion, typically a super-giant O-B star (Tomsick et al, 2006a(Tomsick et al, , 2008Chaty et al, 2008;Masetti et al, 2008b;Negueruela et al, 2008b;Tomsick, 2009;Tomsick et al, 2009b;Bodaghee et al, 2012a).…”

Section: Super-giant Fast X-ray Transientsmentioning

confidence: 99%

High-Mass X-ray Binaries in the Milky Way: A closer look with INTEGRAL

Walter,

Lutovinov,

Bozzo

et al. 2015

Preprint

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High-mass X-ray binaries are fundamental in the study of stellar evolution, nucleosynthesis, structure and evolution of galaxies and accretion processes. Hard X-rays observations by INTEGRAL and Swift have broadened significantly our understanding in particular for the super-giant systems in the Milky Way, which number has increased by almost a factor of three. INTEGRAL played a crucial role in the discovery, study and understanding of heavily obscured systems and of fast X-ray transients. Most super-giant systems can now be classified in three categories: classical/obscured, eccentric and fast transient.The classical systems feature low eccentricity and variability factor of ∼ 10 3 , mostly driven by hydrodynamic phenomena occurring on scales larger than the accretion radius. Among them, systems with short orbital periods and close to Roche-Lobe overflow or with slow winds, appear highly obscured. In eccentric systems, the variability amplitude can reach even higher factors, because of the contrast of the wind density along the orbit. Four super-giant systems, featuring fast outbursts, very short orbital periods and anomalously low accretion rates, are not yet understood.Simulations of the accretion processes on relatively large scales have progressed and reproduce parts of the observations. The combined effects of wind

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New INTEGRAL sources and TeV emission

Cited by 11 publications

References 25 publications

Unveiling the nature ofINTEGRALobjects through optical spectroscopy

Unveiling the nature ofINTEGRALobjects through optical spectroscopy

DISSECTING THE REGION OF 3EG J1837-0423 AND HESS J1841-055 WITHINTEGRAL

High-Mass X-ray Binaries in the Milky Way: A closer look with INTEGRAL

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