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Astronomy & Astrophysics
O. Vilhu, T. R. Kallman, K. I. I. Koljonen, D. C. Hannikainen
Summary: This study estimated the wind velocity on the face-on side of the high-mass X-ray binary Cygnus X-3 based on its spectral state, revealing a correlation between spectral state and accretion luminosities. The findings suggest that soft X-rays in the extreme-UV region from the compact star can penetrate the wind and reduce the line force, affecting the wind velocity on the face-on side.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
A. Ratheesh, F. Tombesi, K. Fukumura, P. Soffitta, E. Costa, D. Kazanas
Summary: The study investigated the origin and geometry of the accretion disc wind in GRS 1915+105 using high-resolution spectroscopy, revealing a possible magnetic origin of the wind and a multiple ionisation component. The observed variability in the line flux between soft and hard states is most likely due to a large increase in the wind density, suggesting an intimate link between accretion and ejection processes in black hole binaries.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
G. Panizo-Espinar, M. Armas Padilla, T. Munoz-Darias, K. I. I. Koljonen, V. A. Cuneo, J. Sanchez-Sierras, D. Mata Sanchez, J. Casares, J. Corral-Santana, R. P. Fender, F. Jimenez-Ibarra, G. Ponti, D. Steeghs, M. A. P. Torres
Summary: This study presents spectroscopic observations of the low mass X-ray binary, MAXI J1348-630, during its bright outburst. The authors found evidence of a cold accretion disc wind in the system, which was similar to those seen in other X-ray transients.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
C. M. Diez, V Grinberg, F. Fuerst, E. Sokolova-Lapa, A. Santangelo, J. Wilms, K. Pottschmidt, S. Martinez-Nunez, C. Malacaria, P. Kretschmar
Summary: Vela X-1 is a complex binary system that provides a key understanding of high-mass X-ray binary accretion processes. This study used NuSTAR to conduct two new observations, allowing for the investigation of accretion geometry and stellar wind properties. The results confirmed anti-correlations between photon index, folding energy, and luminosity, and observed a decrease in cyclotron line energy following a strong flare. The study also found strong variability in absorption, possibly caused by a large-scale structure and variable line of sight.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
E. T. Whelan, A. Murphy, I. Pascucci
Summary: Spectro-astrometry is employed to study the emission from the young intermediate-mass star T CrA, aiming to understand its origin and investigate the potential of spectro-astrometry in tracing MHD disk winds. The analysis shows the presence of a small-scale curved jet inclined parallel to the plane of the sky. This study highlights the importance of spatial information for edge-on disks. The detected jet does not align with the accretion disk or previous observations of outflows likely driven by T CrA. The mass outflow rate is within the range for intermediate-mass stars, indicating the presence of multiple outflows in the T CrA system and the curvature is likely due to the system's multiplicity.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
A. Ratheesh, G. Matt, F. Tombesi, P. Soffitta, M. Pesce-Rollins, A. Di Marco
Summary: This study aims to use X-ray spectro-polarimetry to derive the geometrical properties of absorbing and reflecting matter, with parameters derived from NuSTAR data through hard X-ray spectroscopy. The results suggest that X-ray polarimetric observations can help determine geometrical parameters left unconstrained by spectroscopic analysis.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
G. Panizo-Espinar, T. Munoz-Darias, M. Armas Padilla, F. Jimenez-Ibarra, J. Casares, D. Mata Sanchez
Summary: The study of Aquila X-1's optical spectroscopy did not reveal clear optical wind signatures, but the strong and broad Hα emission line indicates the presence of optically thin ejecta or an extended disc atmosphere. The research also suggests that optical nebular phases may be a relatively common observational feature during the late stages of low mass X-ray binaries' outbursts.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Shigeyuki Karino
Summary: The study investigates how Be-type high-mass X-ray binaries (BeHMXBs) can lead to giant X-ray bursts, with a typical duration of approximately 1 million years. Comparisons with observed BeHMXBs suggest that many binary systems have the potential to become ultraluminous X-ray sources (ULXs) during their evolution.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Shigeyuki Karino
Summary: This study investigates how neutron stars become ultraluminous X-ray sources, and suggests that some ULXs may be special cases of Be-HMXBs. It shows that for a Be-HMXB to become a ULX, the magnetic field of the neutron star and the density of the Be disc need to meet certain conditions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
K. I. I. Koljonen, T. Hovatta
Summary: GRS 1915 +105 is a transient black hole X-ray binary that has experienced a recent decrease in luminosity, but also presents flaring activity at different wavelengths. Studies show that the source has transitioned into a low-luminosity hard X-ray state.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Donna L. dePolo, Richard M. Plotkin, James C. A. Miller-Jones, Jay Strader, Thomas J. Maccarone, Tyrone N. O'Doherty, Laura Chomiuk, Elena Gallo
Summary: This study presents the results of a radio monitoring campaign of A0620 - 00, one of the best-studied and least-luminous known quiescent black hole X-ray binaries. The observations reveal significant variability in the radio emission of A0620 - 00, and the comparison with V404 Cyg suggests that less luminous jets are less variable in quiescence.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
P. Kretschmar, I El Mellah, S. Martinez-Nunez, F. Furst, V Grinberg, A. A. C. Sander, J. van den Eijnden, N. Degenaar, J. Maiz Apellaniz, F. Jimenez Esteban, M. Ramos-Lerate, E. Utrilla
Summary: This article compiles and synthesizes the accumulated knowledge about the Vela X-1 system, provides insights into future research directions, and discusses areas for improvement in observational and modeling aspects. It also highlights the significance of this system in studying the physics of accreting X-ray binaries.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Teo Munoz-Darias, Gabriele Ponti
Summary: Observational signatures of accretion disc winds have been found in low-mass X-ray binaries. A study of the black hole transient V404 Cygni showed that the kinetic properties of the wind in the optical range and X-ray transitions are remarkably similar, suggesting that wind-type X-ray binary outflows might be predominantly multi-phase in nature.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Simone S. Bavera, Tassos Fragos, Emmanouil Zapartas, Enrico Ramirez-Ruiz, Pablo Marchant, Luke Z. Kelley, Michael Zevin, Jeff J. Andrews, Scott Coughlin, Aaron Dotter, Konstantinos Kovlakas, Devina Misra, Juan G. Serra-Perez, Ying Qin, Kyle A. Rocha, Jaime Roman-Garza, Nam H. Tran, Zepei Xing
Summary: The tidal interactions in close binaries can explain the subpopulation of spinning, merging binary black holes and result in long gamma-ray bursts at the time of black-hole formation. This finding allows us to probe the progenitors of binary black-hole mergers well beyond the reach of current gravitational wave observatories.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Xinwu Cao, Bei You, Zhen Yan
Summary: The research reveals that there is a close correlation between the state transition and the peak luminosity of X-ray binaries (XRBs). The constructed disk-outflow model explains this correlation, with strong magnetic fields and high viscosity parameters affecting the relationship between transition luminosity and peak luminosity.
ASTRONOMY & ASTROPHYSICS
(2021)
Correction
Astronomy & Astrophysics
K. I. I. Koljonen, T. J. Maccarone
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2018)
Article
Astronomy & Astrophysics
J. J. E. Kajava, K. I. I. Koljonen, J. Nattila, V. Suleimanov, J. Poutanen
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2017)
Article
Astronomy & Astrophysics
K. I. I. Koljonen, T. J. Maccarone
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2017)
Article
Astronomy & Astrophysics
K. I. I. Koljonen, T. Maccarone, M. L. McCollough, M. Gurwell, S. A. Trushkin, G. G. Pooley, G. Piano, M. Tavani
ASTRONOMY & ASTROPHYSICS
(2018)
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Astronomy & Astrophysics
K. I. I. Koljonen, T. Maccarone, M. L. McCollough, M. Gurwell, S. A. Trushkin, G. G. Pooley, G. Piano, M. Tavani
ASTRONOMY & ASTROPHYSICS
(2018)
Article
Astronomy & Astrophysics
M. Peault, J. Malzac, M. Coriat, T. D. Russell, K. I. I. Koljonen, R. Belmont, S. Corbel, S. Drappeau, J. Ferreira, P. O. Petrucci, J. Rodriguez, D. M. Russell
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2019)
Article
Astronomy & Astrophysics
K. I. I. Koljonen, J. A. Tomsick
ASTRONOMY & ASTROPHYSICS
(2020)
Article
Astronomy & Astrophysics
G. Panizo-Espinar, M. Armas Padilla, T. Munoz-Darias, K. I. I. Koljonen, V. A. Cuneo, J. Sanchez-Sierras, D. Mata Sanchez, J. Casares, J. Corral-Santana, R. P. Fender, F. Jimenez-Ibarra, G. Ponti, D. Steeghs, M. A. P. Torres
Summary: This study presents spectroscopic observations of the low mass X-ray binary, MAXI J1348-630, during its bright outburst. The authors found evidence of a cold accretion disc wind in the system, which was similar to those seen in other X-ray transients.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
K. I. I. Koljonen, K. S. Long, J. H. Matthews, C. Knigge
Summary: Through VLT X-Shooter spectroscopy and Monte Carlo radiative transfer modeling, we investigate the formation of the spectrum in X-ray binary MAXI J1820+070. We find that the spectrum is mainly produced in the transition region between the radiation-driven UV and X-ray outflow and has electron densities consistent with the observed Balmer decrement.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Editorial Material
Multidisciplinary Sciences
I. Liodakis, K. I. I. Koljonen, D. Blinov, E. Lindfors, K. D. Alexander, T. Hovatta, M. Berton, A. Hajela, J. Jormanainen, K. Kouroumpatzakis, N. Mandarakas, K. Nilsson
Summary: A tidal disruption event occurs when a supermassive black hole tears apart a passing star, resulting in the formation of an accretion disk and sometimes a relativistic jet. Our optical polarimetry observations of a TDE, AT 2020mot, reveal a highly polarized synchrotron radiation with a peak linear polarization degree of 25+/-4%. However, our radio observations taken 8 months after the optical peak do not detect the expected radio emission from a relativistic jet. Instead, we propose that the linearly polarized optical emission originates from shocks during accretion disk formation due to collisions within the stream of stellar material.
Article
Astronomy & Astrophysics
Elise Egron, Alberto Pellizzoni, Simona Righini, Marcello Giroletti, Karri Koljonen, Katja Pottschmidt, Sergei Trushkin, Jessica Lobina, Maura Pilia, Joern Wilms, Stephane Corbel, Victoria Grinberg, Sara Loru, Alessio Trois, Jerome Rodriguez, A. Lahteenmaki, M. Tornikoski, S. Enestam, E. Jarvela
Summary: This study reports a giant radio flare event of the microquasar Cygnus X-3 in 2017, with observations of spectral changes and radio orbital modulation. The results indicate significant variations in spectral index during the flare, and a phase shift in the light curves of mini-flares during the decay of the giant flare.
ASTROPHYSICAL JOURNAL
(2021)
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Astronomy & Astrophysics
G-B Zhang, F. Bernardini, D. M. Russell, J. D. Gelfand, J-P Lasota, A. Al Qasim, A. AlMannaei, K. I. I. Koljonen, A. W. Shaw, F. Lewis, J. A. Tomsick, R. M. Plotkin, J. C. A. Miller-Jones, D. Maitra, J. Homan, P. A. Charles, P. Kobel, D. Perez, R. Doran
ASTROPHYSICAL JOURNAL
(2019)
Article
Astronomy & Astrophysics
T. Kallman, M. McCollough, K. Koljonen, D. Liedahl, J. Miller, F. Paerels, G. Pooley, M. Sako, N. Schulz, S. Trushkin, L. Corrales
ASTROPHYSICAL JOURNAL
(2019)
Article
Astronomy & Astrophysics
Karri I. I. Koljonen, David M. Russell
ASTROPHYSICAL JOURNAL
(2019)
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Astronomy & Astrophysics
F. Bernardini, D. M. Russell, A. W. Shaw, F. Lewis, P. A. Charles, K. I. I. Koljonen, J. P. Lasota, J. Casares
ASTROPHYSICAL JOURNAL LETTERS
(2016)