Article
Astronomy & Astrophysics
Jiachen Jiang, Thomas Dauser, Andrew C. Fabian, William N. Alston, Luigi C. Gallo, Michael L. Parker, Christopher S. Reynolds
Summary: This study models the X-ray spectra of IRAS 13224-3809 using multiple flux-resolved XMM-Newton spectra and finds that no additional component is required to fit the soft X-ray excess. The study also calculates the average illumination distance between the corona and the reflection region in IRAS 13224-3809.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Chiara Salvaggio, A. Wolter, A. Belfiore, M. Colpi
Summary: We analyzed all available Chandra observations of the Cartwheel galaxy and its compact group from 2001 to 2008. Our main focus was on the variability in the X-ray band of this collisional ring galaxy. We specifically studied point-like sources, with a particular interest in ultraluminous X-ray sources (ULXs), and found that about one-third of the sources showed long-term variability.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Jiachen Jiang, Huaqing Cheng, Luigi C. Gallo, Luis C. Ho, Douglas J. K. Buisson, Andrew C. Fabian, Fiona A. Harrison, Michael L. Parker, Christopher S. Reynolds, James F. Steiner, John A. Tomsick, Dominic J. Walton, Weimin Yuan
Summary: The Seyfert 1 galaxy KUG 1141+371 has shown a simultaneous flux increase in the optical and UV bands over the past decade, with the latest observations indicating significant changes in UVW2 flux and steady increase in soft X-ray flux. The study suggests that these multiwavelength luminosity changes are likely due to an increase in mass accretion rate, and detailed X-ray spectral analysis reveals variability in X-ray continuum emission and soft excess emission. Additionally, SED models indicate a simultaneous increase in disc temperature and decreasing inner disc radius with increasing accretion rate. Finally, the study discusses a possible connection between KUG 1141+371 and black hole transients in outburst.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Roberto Soria, Manfred W. Pakull
Summary: The study of the galaxy pair NGC1232/NGC1232A with Chandra revealed that there is no diffuse emission cloud in NGC1232, but instead, the small 'companion' galaxy NGC1232A contains three ultraluminous X-ray sources. NGC1232A is similar to the nearby late-type spiral galaxy NGC1313A in terms of mass, morphology, metal abundance, and bright ULX population.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
A. S. Tavleev, G. Lipunova, K. L. Malanchev
Summary: This article introduces a new PYTHON code that calculates the vertical structure and stability of accretion discs around compact objects, taking into account radiative and convective energy transport. Analytic formulas for the farthest regions of the hot disc around a stellar-mass object are provided based on more accurate power-law approximations for opacity. The self-consistent value of the irradiation parameter C-irr is calculated for a self-irradiated disc, showing weak dependence on the accretion rate but changes with radius, driven by the conditions in the photosphere and disc opening angle. The extent of the hot zone is determined by the ratio between irradiating and intrinsic flux.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Thomas J. Maccarone, Nathalie Degenaar, Bailey E. Tetarenko, Craig O. Heinke, Rudy Wijnands, Gregory R. Sivakoff
Summary: The presence of X-ray sources in the Galactic Centre region that show variability but no outbursts in over a decade suggests a large population of stellar mass black holes. It is argued that neutron stars in low-mass X-ray binaries do not have long transient recurrence times. However, this study demonstrates that about half of the known transient low-mass X-ray binaries with neutron star primaries have recurrence times exceeding a decade.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Neal Titus Thomas, S. B. Gudennavar, S. G. Bubbly
Summary: GX 3 + 1, an atoll type neutron star low-mass X-ray binary, was observed four times between 2017 October 5 and 2018 August 9. The source was in the soft spectral state during all four observations. The spectra could be fitted with a model consisting of blackbody and power-law components, giving the blackbody radius and mass accretion rate as approximately 8 km and approximately 2 x 10(-9) M-? y(-1), respectively. One of the observations detected a type I X-ray burst with a rise time of 0.6 s and an e-folding time of 5.6 s. Time-resolved spectral analysis showed a photospheric radius expansion during the burst. The radius and distance of the emitting blackbody in GX 3 + 1 were estimated to be 9.19 (+0.97)(-0.82) km and 10.17 (+0.07)(-0.18) kpc, respectively. Temporal analysis of the burst revealed upper limits of the fractional root mean square amplitude of 7%, 5%, and 6% at different phases of the burst.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Neeraj Kumari, Arghajit Jana, Sachindra Naik, Prantik Nandi
Summary: We conducted a detailed analysis of a small flaring event in the narrow-line Seyfert 1 galaxy NGC 4051 using XMM-Newton and NuSTAR observations. The flare showed an increase in the count rate and a decrease in the reflection fraction, indicating a change in coronal properties. This suggests that the flaring event was due to changes in the corona rather than the accretion disc.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Arghajit Jana
Summary: By collecting spectral data of black hole X-ray binaries (BIIXBs) across different spectral states, the study explores the spectral properties and correlations among different spectral parameters. Interesting correlations and uncertain phenomena are observed in different spectral states.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Tolga Guver, Tugba Bortepe, D. R. Ballantyne, Z. Funda Bostanci, Peter Bult, Gaurava K. Jaisawal, Ersin Gogus, Tod E. Strohmayer, Diego Altamirano, Sebastien Guillot, Deepto Chakrabarty
Summary: In this study, spectral and temporal properties of X-ray bursts from Aql X-1 observed by NICER were analyzed. The results showed short recurrence burst events, significant increase in pre-burst emission with scaling factor, use of reflection models to improve spectral fitting, and highly ionized disc by burst emission with reprocessed emission fraction around 20%.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
F. M. Vincentelli, P. Casella, D. M. Russell, M. C. Baglio, A. Veledina, T. Maccarone, J. Malzac, R. Fender, K. O'Brien, P. Uttley
Summary: This study presents the results of the fast X-ray/infrared variability analysis of the black hole transient MAXI J1535-571, showing a strong asymmetric anticorrelation between X-ray and near-IR light curves. The detection of a near-IR QPO and simultaneous X-ray QPO at approximately the same frequency suggests a possible misalignment between the disc and jet in scenarios for fast IR variability.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
R. C. Ma, R. Soria, L. Tao, W. Zhang, J. L. Qu, S. N. Zhang, L. Zhang, E. L. Qiao, S. J. Zhao, M. Y. Ge, X. B. Li, Y. Huang, L. M. Song, S. Zhang, Q. C. Bu, Y. N. Wang, X. Ma, S. M. Jia
Summary: In this study, we investigated the transient Galactic black hole candidate MAXI J0637-430 using data from Insight-HXMT, Swift, and XMM-Newton. We found that MAXI J0637-430 exhibits unusual characteristics compared to other black hole candidates, including a rapid transition to the thermal dominant state, low peak temperature and luminosity, short decline time-scale, and low soft-to-hard transition luminosity. These properties suggest a small binary separation, short binary period, and low-mass donor star for MAXI J0637-430. Additionally, spectral modelling revealed the need for a second thermal component to explain the thermal emission.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
P. Kosec, C. Pinto, C. S. Reynolds, M. Guainazzi, E. Kara, D. J. Walton, A. C. Fabian, M. L. Parker, I Valtchanov
Summary: Research has shown that ultraluminous X-ray sources (ULXs) commonly exhibit radiation-driven outflows around stellar-mass black holes due to extreme accretion. Through analysis of X-ray spectra, the study revealed the spectral features, properties of the outflows, and the prevalence of such phenomena among ULXs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
S. Harikrishna, K. Sriram
Summary: This study investigates the connection between type-B quasi-periodic oscillations (QPOs) and the hot flow in the inner accretion disc region in black hole X-ray binaries. Spectral and timing studies were conducted on 23 observations, revealing differences in the spectral properties between type-C and type-B QPOs, suggesting that a jet could be responsible for the type-B QPOs. Further research is needed to confirm this scenario.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Matthew J. Middleton, Nick Higginbottom, Christian Knigge, Norman Khan, Grzegorz Wiktorowicz
Summary: The study investigates the impact of radiatively driven outflows in ULXs on the atmosphere of the outer disc, potentially causing unstable heating and significant mass loss. For systems with certain physically relevant parameters, this mass loss may shut off the inflow entirely and lead to limit-cycle behavior.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Q. Daniel Wang
Summary: Recent observations have shown interstellar features that connect energetic activity in the central region of our Galaxy to its halo, although the nature of these features remains uncertain. Chandra mapping has revealed a complex of X-ray-emitting threads and plume-like structures coming from the Galactic Center, indicating that magnetic field re-connection is likely the energy source. Studying the morphological and spectral properties of the radio/X-ray association may provide insights into processes such as interstellar plasma heating, cosmic ray acceleration, and turbulence.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Eric S. Perlman, Eileen T. Meyer, Q. Daniel Wang, Qiang Yuan, Richard Henriksen, Judith Irwin, Jiangtao Li, Theresa Wiegert, Haochuan Li, Yang Yang
Summary: The article discusses new observations of a Tidal Disruption Event (TDE) and analyzes the data from various telescopes. The findings suggest changes in the nuclear radio flux and the interaction of a nuclear jet with interstellar medium, supporting the identification of the event as a TDE.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Yue Hu, A. Lazarian, Q. Daniel Wang
Summary: The magnetic field and turbulence play a crucial role in the galactic center, particularly in the central molecular zone. The magnetic fields associated with ionized gas and radio arcs are in agreement with polarization measurements.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Yang Yang, Judith Irwin, Jiangtao Li, Theresa Wiegert, Q. Daniel Wang, Wei Sun, A. Damas-Segovia, Zhiyuan Li, Zhiqiang Shen, Rene A. M. Walterbos, Carlos J. Vargas
Summary: Through an Expanded VLA Survey and subsequent VLA observations, a nuclear ring and a potential low-luminosity active galactic nucleus (LLAGN) were discovered in the galaxy NGC 5792. The nuclear ring is dominated by nonthermal synchrotron emission and the star formation rate is found to be related to it. These findings reveal the more intense interstellar activity in the galaxy's past.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Yue Hu, A. Lazarian, Q. Daniel Wang
Summary: The Velocity Gradient Technique (VGT) provides an attractive solution for measuring and mapping magnetic fields in the interstellar medium. By applying the VGT to CO data cubes, researchers were able to decompose the magnetic field maps and investigate their significance. The results showed that the VGT has the potential to decompose velocity or density-dependent magnetic structures.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Yun Zheng, Jing Wang, Judith Irwin, Jayanne English, Qingchuan Ma, Ran Wang, Ke Wang, Q. Daniel Wang, Marita Krause, Toky H. Randriamampandry, Jiangtao Li, Rainer Beck
Summary: This study presents the H I distribution of 19 galaxies, with the H I interferometric images of two galaxies being shown for the first time and 12 galaxies having better H I spatial resolutions and/or sensitivities than existing publications. The study finds a correlation between the vertical distribution of H I and the radio continuum intensity scale heights but with differences in the dependence on mass surface density.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Judith Irwin, Jacqueline Dyer, Leonardo Drake, Q. Daniel Wang, Jeroen Stil, Yelena Stein, Jayanne English, Theresa Wiegert
Summary: Catalogues of discrete, compact radio sources in and around 35 edge-on galaxies, as well as catalogues of X-ray sources from Chandra data sets for 27 of the galaxies, are presented. The study detected a total of 2507 sources at L band and 1413 sources at C band. Three new nuclear sources are candidates for low luminosity active galactic nuclei, and new nuclear sources are found in two companion galaxies. A possible foreground double star system with X-ray and radio emissions has also been discovered.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Jiang-Tao Li, Q. Daniel Wang, Theresa Wiegert, Joel N. Bregman, Rainer Beck, Ancor Damas-Segovia, Judith A. Irwin, Li Ji, Yelena Stein, Wei Sun, Yang Yang
Summary: Research findings suggest that active galactic nucleus bubbles play a significant role in accelerating high-energy cosmic rays and galactic feedback. Observations of NGC 4438 in the Virgo cluster reveal the existence of multiscale bubbles produced by the AGN and their interaction with the surrounding interstellar medium. Spectral analysis of the nuclear bubble of NGC 4438 demonstrates that the power-law tail in the X-ray spectra can be explained as synchrotron emission from high-energy cosmic ray leptons. A transient X-ray source near the nucleus of NGC 4438 has also been discovered.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Derek A. Berman, Min S. Yun, K. C. Harrington, P. Kamieneski, J. Lowenthal, B. L. Frye, Q. D. Wang, G. W. Wilson, I Aretxaga, M. Chavez, R. Cybulski, V De la Luz, N. Erickson, D. Ferrusca, D. H. Hughes, A. Montana, G. Narayanan, D. Sanchez-Arguelles, F. P. Schloerb, K. Souccar, E. Terlevich, R. Terlevich, J. A. Zavala
Summary: The Planck All-Sky Survey has identified 22 high-redshift luminous dusty star-forming galaxies (DSFGs) using its candidate list constructed based on the Planck Catalogue of Compact Sources and Wide-field Infrared Survey Explorer all-sky survey. These galaxies have extremely high infrared luminosities and exhibit strong lensing characteristics. Despite their enormous luminosity, little active galactic nucleus (AGN) activity is detected.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Xiao-jie Xu, Q. Daniel Wang, Xiangdong Li
Summary: This study investigates the statistical properties of cataclysmic variables (CVs) by examining their X-ray and optical characteristics. The results show that the distribution of CVs differs at various distances. Additionally, a number of new CV candidates are identified, and their X-ray luminosity and spectral features are analyzed. These findings are important for a comprehensive understanding of CVs and their quantitative contribution to the galactic X-ray background.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Shuinai Zhang, Q. Daniel Wang, Wei Sun, Min Long, Jia Sun, Li Ji
Summary: In the disks of spiral galaxies, diffuse soft X-ray emission is strongly correlated with star-forming regions. However, the origin of this emission is unclear. This study analyzed X-ray emission from a region with enhanced star formation in the northern hot spot of M51 and detected a high G ratio of the O VII He alpha triplet. A physical model involving a thermal plasma and charge exchange with cool gas provides a good explanation for the emission. The study also suggests that charge exchange plays a major role in soft X-ray production.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Jing Wang, Dong Yang, S-H. Oh, Lister Staveley-Smith, Jie Wang, Q. Daniel Wang, Kelley M. Hess, Luis C. Ho, Ligang Hou, Yingjie Jing, Peter Kamphuis, Fujia Li, Xuchen Lin, Ziming Liu, Li Shao, Shun Wang, Ming Zhu
Summary: We use the FAST single-dish radio telescope to map the H i in the NGC 4631 group and identify a significant excess of diffuse H i, which extends over 120 kpc. The diffuse H i is highly turbulent and likely represents a condensing phase of the IGM, induced by active tidal interactions and gas accretion to NGC 4631.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Shu Niu, Fu-Guo Xie, Q. Daniel Wang, Li Ji, Feng Yuan, Min Long
Summary: Despite advances in our understanding of LLAGNs, we still lack fundamental details about the mechanisms of radiation and flare/outburst in hot accretion flow. By analyzing the X-ray data of nearby LLAGN M81*, we find that the X-ray continuum emission likely originates from inverse Compton scattering in the hot accretion flow and flares are rare in M81*. Based on a comparison with Sgr A* and M31*, we propose a magnetohydrodynamical model to universally understand flares in LLAGNs when considering differences in accretion rate and black hole mass.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Yuxuan Zeng, Q. Daniel Wang, Filippo Fraternali
Summary: This study sheds light on the role of energetic outflows from galactic nuclei in shaping galaxy formation and evolution by presenting evidence for a large-scale bipolar radio/X-ray-emitting bubble-like structure in the nearby disc galaxy M106 (NGC 4258).
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Yuping Tang, Q. Daniel Wang, Grant W. Wilson, Mark H. Heyer, Robert A. Gutermuth, Peter Schloerb, Min S. Yun, John Bally, Laurent Loinard, Sergiy Silich, Miguel Chavez, Daryl Haggard, Alfredo Montana, David Sanchez-Arguelles, Milagros Zeballos, Jorge A. Zavala, Jonathan Leon-Tavares
Summary: The research team conducted a large-scale survey of the central molecular zone of our Galaxy and monitored Sgr A*. By combining different data sources, they generated a 1.1 mm continuum map with spatial information and conducted a comprehensive analysis of the spectral energy distribution of dust in the CMZ.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)