The X-Ray Sky | ScienceGate

Recent developments in the field of low-mass X-ray binaries are briefly reviewed, with particular emphasis on a comparison between the systems that contain accreting low magnetic-field neutron stars and those that contain black-hole candidates. The possibility that inclination effects play a role in black-hole candidate phenomenology is explored.

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ULX contribution to stellar feedback: an intermediate-mass black hole candidate and the population of ULXs in the low-metallicity starburst galaxy ESO 338-4

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935414 ◽

2019 ◽

Vol 627 ◽

pp. A63 ◽

Cited By ~ 1

Author(s):

L. M. Oskinova ◽

A. Bik ◽

J. M. Mas-Hesse ◽

M. Hayes ◽

A. Adamo ◽

...

Keyword(s):

Black Holes ◽

Black Hole ◽

Neutron Stars ◽

Formation Rate ◽

Compact Objects ◽

Starburst Galaxy ◽

Intermediate Mass ◽

X Ray ◽

Black Hole Candidate ◽

Stellar Feedback

Context. X-ray radiation from accreting compact objects is an important part of stellar feedback. The metal-poor galaxy ESO 338-4 has experienced vigorous starburst during the last <40 Myr and contains some of the most massive super star clusters in the nearby Universe. Given its starburst age and its star-formation rate, ESO 338-4 is one of the most efficient nearby manufactures of neutron stars and black holes, hence providing an excellent laboratory for feedback studies. Aims. We aim to use X-ray observations with the largest modern X-ray telescopes XMM-Newton and Chandra to unveil the most luminous accreting neutron stars and black holes in ESO 338-4. Methods. We compared X-ray images and spectra with integral field spectroscopic observations in the optical to constrain the nature of strong X-ray emitters. Results. X-ray observations uncover three ultraluminous X-ray sources (ULXs) in ESO 338-4. The brightest among them, ESO 338 X-1, has X-ray luminosity in excess of 1040 erg s−1. We speculate that ESO 338-4 X-1 is powered by accretion on an intermediate-mass (≳300 M⊙) black hole. We show that X-ray radiation from ULXs and hot superbubbles strongly contributes to He II ionization and general stellar feedback in this template starburst galaxy.

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Properties of Faint X-ray Activity of XTE J1908+094 in 2019

Galaxies ◽

10.3390/galaxies9020025 ◽

2021 ◽

Vol 9 (2) ◽

pp. 25

Author(s):

Debjit Chatterjee ◽

Arghajit Jana ◽

Kaushik Chatterjee ◽

Riya Bhowmick ◽

Sujoy Kumar Nath ◽

...

Keyword(s):

Black Hole ◽

Temporal Analysis ◽

Power Density Spectrum ◽

Periodic Oscillations ◽

Telescope Array ◽

Density Spectrum ◽

X Ray ◽

Black Hole Candidate ◽

Short Period ◽

Spectral State

We study the properties of the faint X-ray activity of Galactic transient black hole candidate XTE J1908+094 during its 2019 outburst. Here, we report the results of detailed spectral and temporal analysis during this outburst using observations from Nuclear Spectroscopic Telescope Array (NuSTAR). We have not observed any quasi-periodic-oscillations (QPOs) in the power density spectrum (PDS). The spectral study suggests that the source remained in the softer (more precisely, in the soft–intermediate) spectral state during this short period of X-ray activity. We notice a faint but broad Fe Kα emission line at around 6.5 keV. We also estimate the probable mass of the black hole to be 6.5−0.7+0.5M⊙, with 90% confidence.

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A New View on Young Pulsars in Supernova Remnants: Slow, Radio-quiet & X-ray Bright

International Astronomical Union Colloquium ◽

10.1017/s0252921100061017 ◽

2000 ◽

Vol 177 ◽

pp. 699-702 ◽

Cited By ~ 2

Author(s):

E. V. Gotthelf ◽

G. Vasisht

Keyword(s):

Magnetic Field ◽

Neutron Stars ◽

Supernova Remnants ◽

Simple Explanation ◽

Crab Pulsar ◽

Radio Pulsars ◽

Substantial Fraction ◽

Subsequent Evolution ◽

X Ray ◽

Field Decay

AbstractWe propose a simple explanation for the apparent dearth of radio pulsars associated with young supernova remnants (SNRs). Recent X-ray observations of young remnants have revealed slowly rotating (P∼ 10s) central pulsars with pulsed emission above 2 keV, lacking in detectable radio emission. Some of these objects apparently have enormous magnetic fields, evolving in a manner distinct from the Crab pulsar. We argue that these X-ray pulsars can account for a substantial fraction of the long sought after neutron stars in SNRs and that Crab-like pulsars are perhaps the rarer, but more highly visible example of these stellar embers. Magnetic field decay likely accounts for their high X-ray luminosity, which cannot be explained as rotational energy loss, as for the Crab-like pulsars. We suggest that the natal magnetic field strength of these objects control their subsequent evolution. There are currently almost a dozen slow X-ray pulsars associated with young SNRs. Remarkably, these objects, taken together, represent at least half of the confirmed pulsars in supernova remnants. This being the case, these pulsars must be the progenitors of a vast population of previously unrecognized neutron stars.

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Physical Processes and Parameters in the Magnetosphere of NP 0532

Symposium - International Astronomical Union ◽

10.1017/s0074180900007749 ◽

1971 ◽

Vol 46 ◽

pp. 394-406

Author(s):

F. Pacini

Keyword(s):

Neutron Star ◽

Neutron Stars ◽

Supernova Remnants ◽

Crab Nebula ◽

General Relation ◽

Energy Generation ◽

Main Pulse ◽

Physical Processes ◽

X Ray ◽

The Crab Nebula

The Crab Nebula pulsar conforms to the model of a rotating magnetised neutron star in the rate of energy generation and the exponent of the rotation law.It is suggested that the main pulse is due to electrons and the precursor to protons. Both must radiate in coherent bunches. Optical and X-ray radiation is by the synchrotron process.The wisps observed in the Nebula may represent the release of an instability storing about 1043 erg and 1047–48 particles.Finally, some considerations are made about the general relation between supernova remnants and rotating neutron stars.

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Slow decline and rise of the broad [O iii] emission line in globular cluster black hole candidate RZ2109

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2514 ◽

2019 ◽

Vol 489 (4) ◽

pp. 4783-4790 ◽

Cited By ~ 1

Author(s):

Kristen C Dage ◽

Stephen E Zepf ◽

Arash Bahramian ◽

Jay Strader ◽

Thomas J Maccarone ◽

...

Keyword(s):

Black Hole ◽

Emission Line ◽

Globular Clusters ◽

X Ray ◽

Hydrogen Emission ◽

Black Hole Candidate ◽

The Core ◽

Spectroscopic Monitoring ◽

Slow Decline ◽

Over Time

ABSTRACT RZ2109 is the first of several extragalactic globular clusters shown to host an ultraluminous X-ray source. RZ2109 is particularly notable because optical spectroscopy shows it has broad, luminous [O iii] λλ4959,5007 emission, while also having no detectable hydrogen emission. The X-ray and optical characteristics of the source in RZ2109 make it a good candidate for being a stellar mass black hole accreting from a white dwarf donor (i.e. an ultracompact black hole X-ray binary). In this paper we present optical spectroscopic monitoring of the [O iii]5007 emission line from 2007 to 2018. We find that the flux of the emission line is significantly lower in recent observations from 2016 to 2018 than it was in earlier observations in 2007–2011. We also explore the behaviour of the emission line shape over time. Both the core and the wings of the emission line decline over time, with some evidence that the core declines more rapidly than the wings. However, the most recent observations (in 2019) unexpectedly show the emission line core rebrightening

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Tracing Black Hole Signatures in Several Black Hole Candidates Based on Their X-Ray Spectral Evolution

EPJ Web of Conferences ◽

10.1051/epjconf/202024004001 ◽

2020 ◽

Vol 240 ◽

pp. 04001

Author(s):

Fahmi Iman Alfarizki ◽

Kiki Vierdayanti

Keyword(s):

Black Hole ◽

Compact Object ◽

Spectral Evolution ◽

Thermal Component ◽

X Ray ◽

Black Hole Candidate ◽

Spectral Fitting ◽

Transient Nature ◽

Transient System ◽

Black Hole Candidates

Investigation of spectral evolution of four black hole candidates was carried out by using color-color diagram as well as spectral fitting on Swift/XRT data. Newly found candidates, which are classified as low-mass X-ray binary system based on their transient nature, are the focus of our work. We compare their spectral evolutions to that of XTE J1752-223, a transient system and a more convincing black hole candidate whose mass has been determined from spectral-timing correlation scaling. In addition, comparison to Cygnus X-1, a well-known stellar-mass black hole, was done despite its persistent nature. The spectral fitting, by using a combination of thermal disk and non-thermal component model, results in the innermost temperature values in the range of the typical innermost temperature of black hole binary which is 0.7 – 1.5 keV. The spectral evolutions of the candidates bear a resemblance to both Cygnus X-1 and XTE J1752-223. We note that during Swift/XRT observations, the spectra of Cygnus X-1 and IGR J17451-3022 are mostly dominated by the non- thermal component. We conclude that the compact object of MAXI J1535- 571 and MAXI J1828-249 is highly likely to be a black hole. However, the lack of data rendered conclusive result impossible for IGR J17454-2919.

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TTM Observations of X1755-338

International Astronomical Union Colloquium ◽

10.1017/s0252921100035314 ◽

1995 ◽

Vol 151 ◽

pp. 334-335

Author(s):

H.C. Pan ◽

G.K. Skinner ◽

R.A. Sunyaev ◽

K.N. Borozdin

Keyword(s):

Black Hole ◽

Energy Resolution ◽

Space Station ◽

Galactic Centre ◽

Imaging Spectrometer ◽

X Ray ◽

Black Hole Candidate ◽

Coded Mask

X1755-338 is an X-ray binary source which displays X-ray dips with a 4.4 hour period (White et al. 1984). It was previously noted as an unusually soft X-ray source by Jones (1977) and was suggested later as a black-hole candidate (BHC) by White & Marshall (1984), and White et al. (1984), based on the similarity of its location in an X-ray colour-colour diagram to that of a group of BHCs.The TTM is a coded-mask imaging spectrometer on board the KVANT module of the MIR space station. It is capable of producing images in the 2 – 30 keV band with an energy resolution of about 18% at 6 keV. The instrumental details are given in Brinkman et al. (1985).We observed X1755-338 in 1989 March-September during the period of the TTM Galactic Centre Survey.

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High-Mass X-ray Binaries: progenitors of double compact objects

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319001315 ◽

2018 ◽

Vol 14 (S346) ◽

pp. 1-13

Author(s):

Edward P. J. van den Heuvel

Keyword(s):

Black Holes ◽

Black Hole ◽

Neutron Stars ◽

Compact Objects ◽

High Mass ◽

X Ray ◽

Future Evolution ◽

Short Period ◽

Orbital Periods ◽

X Ray Binaries

AbstractA summary is given of the present state of our knowledge of High-Mass X-ray Binaries (HMXBs), their formation and expected future evolution. Among the HMXB-systems that contain neutron stars, only those that have orbital periods upwards of one year will survive the Common-Envelope (CE) evolution that follows the HMXB phase. These systems may produce close double neutron stars with eccentric orbits. The HMXBs that contain black holes do not necessarily evolve into a CE phase. Systems with relatively short orbital periods will evolve by stable Roche-lobe overflow to short-period Wolf-Rayet (WR) X-ray binaries containing a black hole. Two other ways for the formation of WR X-ray binaries with black holes are identified: CE-evolution of wide HMXBs and homogeneous evolution of very close systems. In all three cases, the final product of the WR X-ray binary will be a double black hole or a black hole neutron star binary.

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Discovery of a New X-ray Transient in Scorpius GRO J1655-40 ≡ X-ray Nova Scorpii 1994

Symposium - International Astronomical Union ◽

10.1017/s0074180900055820 ◽

1996 ◽

Vol 165 ◽

pp. 363-367

Author(s):

W.S. Paciesas ◽

S.N. Zhang ◽

B.C. Rubin ◽

B.A. Harmon ◽

C.A. Wilson ◽

...

Keyword(s):

Black Hole ◽

High Resolution ◽

Power Law ◽

Radio Observations ◽

X Ray ◽

Black Hole Candidate ◽

Radio Jets ◽

Transient Source ◽

Galactic Source ◽

Photon Index

A bright transient X-ray source, GRO J1655-40 (X-ray Nova Scorpii 1994) was discovered with BATSE (the Burst and Transient Source Experiment) in late July 1994. More recently, the source also became a strong radio emitter, its rise in the radio being approximately anti-correlated with a decline in the hard X-ray intensity. High-resolution radio observations subsequent to this symposium showed evidence for superluminally expanding jets. Since the hard X-ray emission extends to at least 200 keV and we find no evidence of pulsations, we tentatively classify the source as a black-hole candidate. However, its hard X-ray spectrum is unusually steep (power-law photon index α ≃ −3) relative to most other black-hole candidates. In this regard, it resembles GRS 1915+105, the first galactic source to show superluminal radio jets.

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