Article
Astronomy & Astrophysics
Alex J. Kemp, Amanda Karakas, Andrew R. Casey, Robert G. Izzard, Ashley J. Ruiter, Poojan Agrawal, Floor S. Broekgaarden, Karel D. Temmink
Summary: This study presents valuable insights into novae phenomena and their evolutionary pathways, as well as simulation research on nova events, discussing the current annual rate of novae in M31 and the variation in II nova rates when common-envelope parameters are adjusted.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Alex J. Kemp, Amanda Karakas, Andrew R. Casey, Chiaki Kobayashi, Robert G. Izzard
Summary: The study reveals a clear anticorrelation between metallicity and the number of novae produced, with fewer novae at higher metallicities. The white dwarf mass distribution shows a systematic variation with metallicity, while the shape of the accretion rate distribution remains relatively stable. The predicted nova rates in the Milky Way and M31 are consistent with observational estimates, but the shape of the white dwarf mass distribution differs significantly from existing observations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Yunlang Guo, Chengyuan Wu, Bo Wang
Summary: Nova outbursts are important for the chemical evolution of Galaxy, and the He-mixing process significantly affects the mass fraction of H and He in nova ejecta, as well as influences the duration and mass of nova cycles. The nuclear energy generation rate of p-p chains decreases with He-mixing during nova outbursts, while the CNO-cycle increases. This study develops a He-mixing meter that can estimate the He-mixing fraction in classical nova systems.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Yael Hillman
Summary: This study presents a detailed analysis of seven models, finding common features on different time scales and dependency on either WD or RD mass for certain characteristics. The comparison between WD models with different core compositions reveals significant impacts on heavy element abundances in the ejecta composition.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Michael M. Shara, Steve B. Howell, Elise Furlan, Crystal L. Gnilka, Anthony F. J. Moffat, Nicholas J. Scott, David Zurek
Summary: A survey of six nearest and brightest cataclysmic variables found no main-sequence companions, indicating that main-sequence triple companions to cataclysmic variables are not very common. However, the presence of faintest M dwarfs or close brown dwarf companions cannot be ruled out.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Bradley E. Schaefer, Frederick M. Walter, Rebekah Hounsell, Yael Hillman
Summary: KT Eridani is a recurrent nova with a high white dwarf mass and accretion rate. Through analysis of light curves, spectral energy distributions, and radial velocity curves, we have determined the orbital period, companion star temperature, and absolute magnitude of KT Eri.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Yiqi Liu, Hsiang-Chih Hwang, Nadia L. Zakamska, John R. Thorstensen
Summary: CSS1603+19 is a cataclysmic variable with a short orbital period and a strong mid-infrared excess. Time-resolved multiwavelength observations reveal eclipsing-like variability and possible cyclotron features in the system. The spectra show double-peaked emission lines with radial velocity variations, and a physical model suggests an accretion column and a Roche overflow point as the origins of the components. The masses of the binary components are constrained to be M-1 > 0.24 M-circle dot and M-2 = 0.0644 +/- 0.0074 M-circle dot for the white dwarf accretor and the donor, respectively. The system is classified as an AM Herculis star or a polar.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Yael Hillman, Maya Gerbi
Summary: The development of a nova eruption depends on the mass and accretion rate of a white dwarf. The concentration of heavy elements in the accreted material affects the eruption features, and the ignition of the thermonuclear runaway depends on the accumulation of heavy elements.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Yael Hillman
Summary: Fluctuations observed during nova eruptions may be caused by the repeated approach and recession of the convective front from the surface. This mechanism is more likely to occur in low-mass white dwarfs and during long accretion phases.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
J. van Roestel, T. Kupfer, M. J. Green, T. L. S. Wong, L. Bildsten, K. Burdge, T. Prince, T. R. Marsh, P. Szkody, C. Fremling, M. J. Graham, V. S. Dhillon, S. P. Littlefair, E. C. Bellm, M. Coughlin, D. A. Duev, D. A. Goldstein, R. R. Laher, B. Rusholme, R. Riddle, R. Dekany, S. R. Kulkarni
Summary: We report the discovery of five new eclipsing AM CVn systems using the Zwicky Transient Facility (ZTF) light curves of white dwarfs selected using Gaia parallaxes. The systems were confirmed through phase-resolved spectroscopy and high-speed photometry. The presence of previously unseen spectral features in these systems provides insight into their evolutionary channels.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Wei-Min Liu, Long Jiang, Wen-Cong Chen, Xiang-Dong Li
Summary: The disc instability mechanism (DIM) is responsible for the transient behavior of dwarf novae (DNe), with duty cycles playing a crucial role in the long-term binary evolution. Through systematic investigation, it is found that a specific range of duty cycles is required for efficient white dwarf (WD) mass growth. While the DIM significantly influences the accretion process, none of the carbon-oxygen (CO) WDs in the simulations can reach the explosion mass of Type Ia supernovae. The DIM in DNe could partially alleviate the WD mass problem.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Natsuko Yamaguchi, Kareem El-Badry, Antonio C. Rodriguez, Maude Gull, Benjamin R. Roulston, Zachary P. Vanderbosch
Summary: In this study, follow-up spectroscopy of 21 cataclysmic variables (CVs) with evolved secondaries and ongoing or recently terminated mass transfer was conducted. The sodium (Na) abundances of the donors were measured to test evolutionary models, and it was found that all objects in the sample had enhanced Na abundances. Binary evolution models of CVs were used to interpret the results, which predicted Na enhancement in the donors' cores near the end of their main-sequence evolution. The observed [Na/H] values were on average approximately 0.3 dex higher than predicted by the models.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Kareem El-Badry, Hans-Walter Rix, Eliot Quataert, Thomas Kupfer, Ken J. Shen
Summary: A systematic survey identified 51 mass-transferring and recently detached cataclysmic variables with evolved secondaries, potentially progenitors of extremely low mass white dwarfs, AM CVn systems, and detached ultracompact binaries. Most found secondaries are hotter, with those above 7000 K being in a detached state, while those below 7000 K are still mass-transferring. This discovery triples the known evolved CV population and presents opportunities for enhancing understanding of compact binary populations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Kareem El-Badry, Eliot Quataert, Hans-Walter Rix, Daniel R. Weisz, Thomas Kupfer, Ken J. Shen, Maosheng Xiang, Yong Yang, Xiaowei Liu
Summary: A close binary system has been discovered consisting of a bloated, low-mass proto-white dwarf and a massive white dwarf companion. The proto-white dwarf is cooler and more puffy than any known extremely low-mass white dwarf, possibly undergoing ongoing or recently terminated mass transfer.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
S. G. Parsons, B. T. Gansicke, M. R. Schreiber, T. R. Marsh, R. P. Ashley, E. Breedt, S. P. Littlefair, H. Meusinger
Summary: Magnitude-limited samples have shown that a higher percentage of cataclysmic variables contain white dwarfs with strong magnetic fields compared to single white dwarfs. The lack of identifiable progenitor systems for magnetic cataclysmic variables presents challenges in understanding their formation and evolution. In a sample of magnetic white dwarfs in detached binaries, it is found that they are more massive and have cooling ages of over 1Gyr, residing in systems close to Roche lobe filling. Unusual asymmetric light curves may be a way to identify these systems in larger numbers in the future.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Gordon T. Richards, Richard M. Plotkin, Paul C. Hewett, Amy L. Rankine, Angelica B. Rivera, Yue Shen, Ohad Shemmer
Summary: Researchers have proposed a hypothesis for determining the comparatively edge-on orientation in a subset of quasars, which could apply to individual quasars without needing radio or X-ray data. By using moderate resolution and signal-to-noise spectroscopy to identify some quasars as more edge-on than average, this orientation indicator could potentially be valuable in understanding quasars. Further X-ray observations and additional data are needed to confirm and calibrate this hypothesis.
ASTROPHYSICAL JOURNAL LETTERS
(2021)
Article
Astronomy & Astrophysics
Alessandro Paduano, Arash Bahramian, James C. A. Miller-Jones, Adela Kawka, Jay Strader, Laura Chomiuk, Craig O. Heinke, Thomas J. Maccarone, Christopher T. Britt, Richard M. Plotkin, Aarran W. Shaw, Laura Shishkovsky, Evangelia Tremou, Vlad Tudor, Gregory R. Sivakoff
Summary: Transitional millisecond pulsars are pulsars that switch between rotation-powered millisecond pulsar state and accretion-powered X-ray binary state, considered as an evolutionary stage between neutron star low-mass X-ray binaries and millisecond pulsars. NGC 6652B, a low-mass X-ray binary in the globular cluster NGC 6652, is observed to display prolonged X-ray flaring behavior and variable optical spectra.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
J. van den Eijnden, N. Degenaar, T. D. Russell, R. Wijnands, A. Bahramian, J. C. A. Miller-Jones, J. V. Hernandez Santisteban, E. Gallo, P. Atri, R. M. Plotkin, T. J. Maccarone, G. Sivakoff, J. M. Miller, M. Reynolds, D. M. Russell, D. Maitra, C. O. Heinke, M. Armas Padilla, A. W. Shaw
Summary: Our study presents new radio observations of a sample of 36 neutron star X-ray binaries, revealing some of their properties. It is found that strongly magnetized neutron stars are typically radio fainter than weakly magnetized ones, and the origin of radio emission in high-mass X-ray binaries is discussed.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Q. Ni, W. N. Brandt, B. Luo, G. P. Garmire, P. B. Hall, R. M. Plotkin, O. Shemmer, J. D. I. I. I. I. I. I. Timlin, F. Vito, J. Wu, W. Yi
Summary: Deeper Chandra observations of weak-line quasars (WLQs) in a representative sample with previously limited X-ray constraints reveal diverse X-ray properties, with some showing extreme variability. The study supports the thick disc and outflow (TDO) model in explaining WLQs' X-ray and multiwavelength properties, with an average covering factor and a range of column densities leading to different levels of absorption and Compton reflection (and/or scattering) among WLQs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Roberto Soria, Mari Kolehmainen, Alister W. Graham, Douglas A. Swartz, Mihoko Yukita, Christian Motch, Thomas H. Jarrett, James C. A. Miller-Jones, Richard M. Plotkin, Thomas J. Maccarone, Laura Ferrarese, Alexander Guest, Ariane Lancon
Summary: In this study, we analyze the population of ultraluminous X-ray sources (ULXs) in late-type galaxies in the Virgo cluster. We find that the ULX luminosity function is related to the mass and star formation rate of the galaxies, and we tentatively identify the most luminous X-ray source as a recent supernova or its remnant.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Ava E. Covington, Aarran W. Shaw, Koji Mukai, Colin Littlefield, Craig O. Heinke, Richard M. Plotkin, Doug Barrett, James Boardman, David Boyd, Stephen M. Brincat, Rolf Carstens, Donald F. Collins, Lewis M. Cook, Walter R. Cooney, David Cejudo Fernandez, Sjoerd Dufoer, Shawn Dvorak, Charles Galdies, William Goff, Franz-Josef Hambsch, Steve Johnston, Jim Jones, Kenneth Menzies, Libert A. G. Monard, Etienne Morelle, Peter Nelson, Yenal Ogmen, John W. Rock, Richard Sabo, Jim Seargeant, Geoffrey Stone, Joseph Ulowetz, Tonny Vanmunster
Summary: We present optical photometry of six intermediate polars that show transitions to a low-flux state. Our analysis reveals that the light curves and periodicities of four systems change as the flux decreases, indicating a change in the accretion properties during the transition.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Weimin Yi, W. N. Brandt, Q. Ni, Luis C. Ho, Bin Luo, Wei Yan, D. P. Schneider, Jeremiah D. Paul, Richard M. Plotkin, Jinyi Yang, Feige Wang, Zhicheng He, Chen Chen, Xue-Bing Wu, Jin-Ming Bai
Summary: Our analysis confirmed the WLQ nature and the transformation from LoBAL to HiBAL, with an increase of a factor of 2 in the Mg ii+Fe ii emission strength and a decrease of 0.1 in E(B - V) over two decades. The kinetic power of the LoBAL wind at a distance of about 15 pc from the BH is estimated to be approximately 43% of the Eddington luminosity, capable of providing quasar feedback to its host galaxy with an order-of-magnitude uncertainty.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Jeremiah D. Paul, Richard M. Plotkin, Ohad Shemmer, Scott F. Anderson, W. N. Brandt, Xiaohui Fan, Elena Gallo, Bin Luo, Qingling Ni, Gordon T. Richards, Donald P. Schneider, Jianfeng Wu, Weimin Yi
Summary: This study presents ultraviolet spectroscopy of low-redshift weak emission-line quasars (WLQs), exploring their connection with high-redshift WLQ populations. The results suggest a soft ionizing continuum scenario for WLQs and indicate that weak absorption may be a significant contaminant in low-redshift WLQ populations.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Vlad Tudor, James C. A. Miller-Jones, Jay Strader, Arash Bahramian, Laura Shishkovsky, Richard M. Plotkin, Laura Chomiuk, Craig O. Heinke, Thomas J. Maccarone, Gregory R. Sivakoff, Evangelia Tremou, Gemma E. Anderson, Thomas D. Russell, Anastasios K. Tzioumis
Summary: Radio continuum observations provide a new perspective on compact objects in globular clusters, and this survey has led to the discovery of previously unknown sources in these clusters.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
A. W. Shaw, J. M. Miller, V Grinberg, D. J. K. Buisson, C. O. Heinke, R. M. Plotkin, J. A. Tomsick, A. Bahramian, P. Gandhi, G. R. Sivakoff
Summary: Through observations and analysis using Chandra, we found numerous highly ionized metal lines in the X-ray spectra of the Galactic black hole X-ray binary V4641 Sgr. These lines originate from an obscured central engine and potentially come from an accretion disc wind with spherical geometry.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
P. Atri, J. C. A. Miller-Jones, A. Bahramian, R. M. Plotkin, T. J. Maccarone, B. Marcote, C. O. Heinke, G. R. Sivakoff, A. Ginsburg, J. Strader, L. Chomiuk
Summary: In this study, high precision astrometry was conducted on a sample of 33 compact, flat spectrum, variable radio sources. The possibility of these sources being black hole X-ray binaries (BHXBs) was not ruled out. Several Galactic candidates were identified based on their proper motions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
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
Erica Thygesen, Richard M. Plotkin, Roberto Soria, Amy E. Reines, Jenny E. Greene, Gemma E. Anderson, Vivienne F. Baldassare, Milo G. Owens, Ryan T. Urquhart, Elena Gallo, James C. A. Miller-Jones, Jeremiah D. Paul, Alexandar P. Rollings
Summary: Through observations of three nearby dwarf galaxies, we find that two of them contain X-ray sources without corresponding radio emission, suggesting they may be luminous X-ray binaries. The third galaxy contains two X-ray sources and exhibits low metallicity and nebular emission features.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Qian Yang, Paul J. Green, Chelsea L. MacLeod, Richard M. Plotkin, Scott F. Anderson, Allyson Bieryla, Francesca Civano, Michael Eracleous, Matthew Graham, John J. Ruan, Jessie Runnoe, Xiurui Zhao
Summary: Extremely variable quasars, known as changing-look quasars (CLQs), show strong changes in broad-line emission strength. A pilot sample of CLQs with X-ray observations in both bright and faint states is presented for studying the CLQ transition mechanism. These observations indicate that the changes in the CLQs are likely due to the changing accretion rate of the supermassive black hole, leading to multiwavelength emission variations similar to accretion states of X-ray binaries.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Sneha Nair, Kristen C. Dage, Daryl Haggard, Arunav Kundu, Richard M. Plotkin, Katherine L. Rhode, Stephen E. Zepf
Summary: Using archival data from the Chandra X-ray Observatory and catalogues from the Hubble Space Telescope, this study investigates the time-domain properties of low mass X-ray binaries in the elliptical galaxy NGC 4261. Out of the 98 identified X-ray sources, 62 are within the optical field of view, with 33% aligned with an optical cluster counterpart. The study identifies 20 X-ray sources coincident with globular clusters, including ultra-luminous X-ray sources and low mass X-ray binaries.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
