Open Access. Powered by Scholars. Published by Universities.®
- Discipline
Articles 1 - 30 of 59
Full-Text Articles in Entire DC Network
Dynamical Modelling Of Cxogbs J175553.2-281633: A 10 H Long Orbital Period Cataclysmic Variable, Sebastian Gomez, Manuel A. P. Torres, Peter G. Jonker, Zuzanna Kostrzewa-Rutkowska, Theo F. J. Van Grunsven, Andrzej Udalski, Robert I. Hynes, Craig O. Heinke, Thomas J. Maccarone, Ricardo Salinas, Jay Strader
Dynamical Modelling Of Cxogbs J175553.2-281633: A 10 H Long Orbital Period Cataclysmic Variable, Sebastian Gomez, Manuel A. P. Torres, Peter G. Jonker, Zuzanna Kostrzewa-Rutkowska, Theo F. J. Van Grunsven, Andrzej Udalski, Robert I. Hynes, Craig O. Heinke, Thomas J. Maccarone, Ricardo Salinas, Jay Strader
Faculty Publications
We present modelling of the long-term optical light and radial velocity curves of the binary stellar system CXOGBS J175553.2-281633, first detected in X-rays in the Chandra Galactic Bulge Survey. We analysed 7 yr of optical I-band photometry from Optical Gravitational Lensing Experiment and found long-term variations from year to year. These long-term variations can most likely be explained with by either variations in the luminosity of the accretion disc or a spotted secondary star. The phased light curve has a sinusoidal shape, which we interpret as being due to ellipsoidal modulations. We improve the orbital period to be P = …
Optical And X-Ray Correlations During The 2015 Outburst Of The Black Hole V404 Cyg, R. I. Hynes, E. L. Robinson, D. M. Terndrup, P. Gandhi, C. S. Froning, R. M. Wagner, S. Starrfield, V. S. Dhillon, T. R. Marsh
Optical And X-Ray Correlations During The 2015 Outburst Of The Black Hole V404 Cyg, R. I. Hynes, E. L. Robinson, D. M. Terndrup, P. Gandhi, C. S. Froning, R. M. Wagner, S. Starrfield, V. S. Dhillon, T. R. Marsh
Faculty Publications
We present a serendipitous multiwavelength campaign of optical photometry simultaneous with Integral X-ray monitoring of the 2015 outburst of the black hole V404 Cyg. Largeamplitude optical variability is generally correlated with X-rays, with lags of order a minute or less compatible with binary light travel time-scales or jet ejections. Rapid optical flaring on time-scales of seconds or less is incompatible with binary light-travel time-scales and has instead been associated with synchrotron emission from a jet. Both this rapid jet response and the lagged and smeared one can be present simultaneously. The optical brightness is not uniquely determined by the X-ray …
Numerical Simulations Of Mass Transfer In Binaries With Bipolytropic Components, Kundan Kadam, Patrick M. Motl, Dominic C. Marcello, Juhan Frank, Geoffrey C. Clayton
Numerical Simulations Of Mass Transfer In Binaries With Bipolytropic Components, Kundan Kadam, Patrick M. Motl, Dominic C. Marcello, Juhan Frank, Geoffrey C. Clayton
Faculty Publications
We present the first self-consistent three-dimensional study of hydrodynamic simulations of mass transfer in binary systems with bipolytropic (composite polytropic) components. In certain systems, such as contact binaries or during the common-envelope phase, the core- envelope structure of the stars plays an important role in binary interactions. In this paper, we compare mass transfer simulations of bipolytropic binary systems in order to test the suitability of our numerical tools for investigating the dynamical behaviour of such systems. The initial, equilibrium binary models possess a core-envelope structure and are obtained using the bipolytropic self-consistent field technique. We conduct mass transfer simulations …
Continuum Reverberation Mapping Of The Accretion Disks In Two Seyfert 1 Galaxies, M. M. Fausnaugh, D. A. Starkey, Keith Horne, C. S. Kochanek, B. M. Peterson, M. C. Bentz, K. D. Denney, C. J. Grier, D. Grupe, R. W. Pogge, G. De Rosa, S. M. Adams, A. J. Barth, Thomas G. Beatty, A. Bhattacharjee, G. A. Borman, T. A. Boroson, M. C. Bottorff, Jacob E. Brown, Jonathan S. Brown, M. S. Brotherton, C. T. Coker, S. M. Crawford, K. V. Croxall, Sarah Eftekharzadeh, Michael Eracleous, M. D. Joner, C. B. Henderson, T. W.S. Holoien, T. Hutchison, Shai Kaspi, S. Kim, Anthea L. King
Continuum Reverberation Mapping Of The Accretion Disks In Two Seyfert 1 Galaxies, M. M. Fausnaugh, D. A. Starkey, Keith Horne, C. S. Kochanek, B. M. Peterson, M. C. Bentz, K. D. Denney, C. J. Grier, D. Grupe, R. W. Pogge, G. De Rosa, S. M. Adams, A. J. Barth, Thomas G. Beatty, A. Bhattacharjee, G. A. Borman, T. A. Boroson, M. C. Bottorff, Jacob E. Brown, Jonathan S. Brown, M. S. Brotherton, C. T. Coker, S. M. Crawford, K. V. Croxall, Sarah Eftekharzadeh, Michael Eracleous, M. D. Joner, C. B. Henderson, T. W.S. Holoien, T. Hutchison, Shai Kaspi, S. Kim, Anthea L. King
Faculty Publications
We present optical continuum lags for two Seyfert 1 galaxies, MCG+08-11-011 and NGC 2617, using monitoring data from a reverberation mapping campaign carried out in 2014. Our light curves span the ugriz filters over four months, with median cadences of 1.0 and 0.6 days for MCG+08-11-011 and NGC 2617, respectively, combined with roughly daily X-ray and near-UV data from Swift for NGC 2617. We find lags consistent with geometrically thin accretion-disk models that predict a lag-wavelength relation of τ ∝ λ 4/3. However, the observed lags are larger than predictions based on standard thin-disk theory by factors of 3.3 for …
Spectroscopic Classification Of X-Ray Sources In The Galactic Bulge Survey, T. Wevers, M. A.P. Torres, P. G. Jonker, G. Nelemans, C. Heinke, D. Mata Sánchez, C. B. Johnson, R. Gazer, D. T.H. Steeghs, T. J. Maccarone, R. I. Hynes, J. Casares, A. Udalski, J. Wetuski, C. T. Britt, Z. Kostrzewa-Rutkowska, L. Wyrzykowski
Spectroscopic Classification Of X-Ray Sources In The Galactic Bulge Survey, T. Wevers, M. A.P. Torres, P. G. Jonker, G. Nelemans, C. Heinke, D. Mata Sánchez, C. B. Johnson, R. Gazer, D. T.H. Steeghs, T. J. Maccarone, R. I. Hynes, J. Casares, A. Udalski, J. Wetuski, C. T. Britt, Z. Kostrzewa-Rutkowska, L. Wyrzykowski
Faculty Publications
We present the classification of 26 optical counterparts to X-ray sources discovered in the Galactic Bulge Survey. We use (time-resolved) photometric and spectroscopic observations to classify the X-ray sources based on their multiwavelength properties. We find a variety of source classes, spanning different phases of stellar/binary evolution. We classify CX21 as a quiescent cataclysmic variable (CV) below the period gap, and CX118 as a high accretion rate (nova-like) CV. CXB12 displays excess UV emission, and could contain a compact object with a giant star companion, making it a candidate symbiotic binary or quiescent low-mass X-ray binary (although other scenarios cannot …
Upper Limits On Gravitational Waves From Scorpius X-1 From A Model-Based Cross-Correlation Search In Advanced Ligo Data, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. Antier, S. Appert, K. Arai, M. C. Araya, J. S. Areeda
Upper Limits On Gravitational Waves From Scorpius X-1 From A Model-Based Cross-Correlation Search In Advanced Ligo Data, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. Antier, S. Appert, K. Arai, M. C. Araya, J. S. Areeda
Faculty Publications
We present the results of a semicoherent search for continuous gravitational waves from the low-mass X-ray binary Scorpius X-1, using data from the first Advanced LIGO observing run. The search method uses details of the modeled, parametrized continuous signal to combine coherently data separated by less than a specified coherence time, which can be adjusted to trade off sensitivity against computational cost. A search was conducted over the frequency range 25-2000 Hz, spanning the current observationally constrained range of binary orbital parameters. No significant detection candidates were found, and frequency-dependent upper limits were set using a combination of sensitivity estimates …
Expanding Hot Flow In The Black Hole Binary Swift J1753.5-0127: Evidence From Optical Timing, Alexandra Veledina, Poshak Gandhi, Robert Hynes, Jari J.E. Kajava, Sergey S. Tsygankov, Michail G. Revnivtsev, Martin Durant, Juri Poutanen
Expanding Hot Flow In The Black Hole Binary Swift J1753.5-0127: Evidence From Optical Timing, Alexandra Veledina, Poshak Gandhi, Robert Hynes, Jari J.E. Kajava, Sergey S. Tsygankov, Michail G. Revnivtsev, Martin Durant, Juri Poutanen
Faculty Publications
We describe the evolution of optical and X-ray temporal characteristics during the outburst decline of the black hole X-ray binary SWIFT J1753.5-0127. The optical/X-ray crosscorrelation function demonstrates a single positive correlation at the outburst peak, then it has multiple dips and peaks during the decline stage, which are then replaced by the precognition dip plus peak structure in the outburst tail. Power spectral densities and phase lags show a complex evolution, revealing the presence of intrinsically connected optical and X-ray quasi-periodic oscillations. For the first time, we quantitatively explain the evolution of these timing properties during the entire outburst within …
Dippers And Dusty Disc Edges: New Diagnostics And Comparison To Model Predictions, Eva H.L. Bodman, Alice C. Quillen, Megan Ansdell, Michael Hippke, Tabetha S. Boyajian, Eric E. Mamajek, Eric G. Blackman, Aaron Rizzuto, Joel H. Kastner
Dippers And Dusty Disc Edges: New Diagnostics And Comparison To Model Predictions, Eva H.L. Bodman, Alice C. Quillen, Megan Ansdell, Michael Hippke, Tabetha S. Boyajian, Eric E. Mamajek, Eric G. Blackman, Aaron Rizzuto, Joel H. Kastner
Faculty Publications
We revisit the nature of large dips in flux from extinction by dusty circumstellar material that is observed by Kepler for many young stars in the Upper Sco and ρ Oph star formation regions. These young, low-mass 'dipper' stars are known to have low accretion rates and primarily hostmoderately evolved dusty circumstellar discs. Young low-mass stars often exhibit rotating starspots that cause quasi-periodic photometric variations. We found no evidence for periods associated with the dips that are different from the starspot rotation period in spectrograms constructed from the light curves. The material causing the dips in most of these light …
System Mass Constraints For The Accreting Millisecond Pulsar Xte J1814-338 Using Bowen Fluorescence, L. Wang, D. Steeghs, J. Casares, P. A. Charles, T. Muñoz-Darias, T. R. Marsh, R. I. Hynes, K. O'Brien
System Mass Constraints For The Accreting Millisecond Pulsar Xte J1814-338 Using Bowen Fluorescence, L. Wang, D. Steeghs, J. Casares, P. A. Charles, T. Muñoz-Darias, T. R. Marsh, R. I. Hynes, K. O'Brien
Faculty Publications
We present phase-resolved spectroscopy of the millisecond X-ray pulsar XTE J1814-338 obtained during its 2003 outburst. The spectra are dominated by high-excitation emission lines of He II λ4686, Hβ, and the Bowen blend C III/N III 4630-50 Å. We exploit the proven Bowen fluorescence technique to establish a complete set of dynamical system parameter constraints using bootstrap Doppler tomography, a first for an accreting millisecond X-ray pulsar binary. The reconstructed Doppler map of the NIII λ4640 Bowen transition exhibits a statistically significant (>4σ) spot feature at the expected position of the companion star. If this feature is driven by …
Discovery Of A High State Am Cvn Binary In The Galactic Bulge Survey, T. Wevers, M. A.P. Torres, P. G. Jonker, J. D. Wetuski, G. Nelemans, D. Steeghs, T. J. Maccarone, C. Heinke, R. I. Hynes, A. Udalski, Z. Kostrzewa-Rutkowska, P. J. Groot, R. Gazer, M. K. Szymański, C. T. Britt, L. Wyrzykowski, R. Poleski
Discovery Of A High State Am Cvn Binary In The Galactic Bulge Survey, T. Wevers, M. A.P. Torres, P. G. Jonker, J. D. Wetuski, G. Nelemans, D. Steeghs, T. J. Maccarone, C. Heinke, R. I. Hynes, A. Udalski, Z. Kostrzewa-Rutkowska, P. J. Groot, R. Gazer, M. K. Szymański, C. T. Britt, L. Wyrzykowski, R. Poleski
Faculty Publications
We report on the discovery of a hydrogen-deficient compact binary (CXOGBS J175107.6- 294037) belonging to the AM CVn class in the Galactic Bulge Survey. Deep archival X-ray observations constrain the X-ray positional uncertainty of the source to 0.57 arcsec, and allow us to uniquely identify the optical and UV counterpart. Optical spectroscopic observations reveal the presence of broad, shallow He I absorption lines while no sign of hydrogen is present, consistent with a high state system. We present the optical light curve from Optical Gravitational Lensing Experiment monitoring, spanning 15 yr. It shows no evidence for outbursts; variability is present …
Furiously Fast And Red: Sub-Second Optical Flaring In V404 Cyg During The 2015 Outburst Peak, P. Gandhi, S. P. Littlefair, L. K. Hardy, V. S. Dhillon, T. R. Marsh, A. W. Shaw, D. Altamirano, M. D. Caballero-Garcia, J. Casares, P. Casella, A. J. Castro-Tirado, P. A. Charles, Y. Dallilar, S. Eikenberry, R. P. Fender, R. I. Hynes, C. Knigge, E. Kuulkers, K. Mooley, T. Muñoz-Darias, M. Pahari, F. Rahoui, D. M. Russell, J. V. Hernández Santisteban, T. Shahbaz, D. M. Terndrup, J. Tomsick, D. J. Walton
Furiously Fast And Red: Sub-Second Optical Flaring In V404 Cyg During The 2015 Outburst Peak, P. Gandhi, S. P. Littlefair, L. K. Hardy, V. S. Dhillon, T. R. Marsh, A. W. Shaw, D. Altamirano, M. D. Caballero-Garcia, J. Casares, P. Casella, A. J. Castro-Tirado, P. A. Charles, Y. Dallilar, S. Eikenberry, R. P. Fender, R. I. Hynes, C. Knigge, E. Kuulkers, K. Mooley, T. Muñoz-Darias, M. Pahari, F. Rahoui, D. M. Russell, J. V. Hernández Santisteban, T. Shahbaz, D. M. Terndrup, J. Tomsick, D. J. Walton
Faculty Publications
We present observations of rapid (sub-second) optical flux variability in V404 Cyg during its 2015 June outburst. Simultaneous three-band observations with the ULTRACAM fast imager on four nights show steep power spectra dominated by slow variations on ~100-1000 s time-scales. Near the peak of the outburst on June 26, a dramatic change occurs and additional, persistent sub-second optical flaring appears close in time to giant radio and X-ray flaring. The flares reach peak optical luminosities of ~ few × 1036 erg s-1. Some are unresolved down to a time resolution of 24 ms. Whereas the fast flares are stronger in …
Discovery Of The Candidate Off-Nuclear Ultrasoft Hyper-Luminous X-Ray Source 3xmm J141711.1+522541, Dacheng Lin, Eleazar Carrasco, Natalie Webb, Jimmy Irwin, Renato Dupke, Aaron Romanowsky, Enrico Ramirez-Ruiz, Jay Strader, Jeroen Homan, Didier Barret, Olivier Godet
Discovery Of The Candidate Off-Nuclear Ultrasoft Hyper-Luminous X-Ray Source 3xmm J141711.1+522541, Dacheng Lin, Eleazar Carrasco, Natalie Webb, Jimmy Irwin, Renato Dupke, Aaron Romanowsky, Enrico Ramirez-Ruiz, Jay Strader, Jeroen Homan, Didier Barret, Olivier Godet
Faculty Publications
No abstract provided.
The Relationship Between X-Ray Luminosity And Duty Cycle For Dwarf Novae And Their Specific Frequency In The Inner Galaxy, C. T. Britt, T. Maccarone, M. L. Pretorius, R. I. Hynes, P. G. Jonker, M. A.P. Torres, C. Knigge, C. O. Johnson, C. B. Heinke, D. Steeghs, S. Greiss, G. Nelemans
The Relationship Between X-Ray Luminosity And Duty Cycle For Dwarf Novae And Their Specific Frequency In The Inner Galaxy, C. T. Britt, T. Maccarone, M. L. Pretorius, R. I. Hynes, P. G. Jonker, M. A.P. Torres, C. Knigge, C. O. Johnson, C. B. Heinke, D. Steeghs, S. Greiss, G. Nelemans
Faculty Publications
We measure the duty cycles for an existing sample of well-observed, nearby dwarf novae (DNe) using data from American Association of Variable Star Observers, and present a quantitative empirical relation between the duty cycle of DNe outbursts and the X-ray luminosity of the system in quiescence. We have found that logDC = 0.63(±0.21) x (log LX(erg s-1) - 31.3) - 0.95(±0.1), where DC stands for duty cycle. We note that there is intrinsic scatter in this relation greater than what is expected from purely statistical errors. Using the DN X-ray luminosity functions from Pretorius & Knigge and Byckling et al., …
Sco X-1 Revisited With Kepler, Maxi And Hermes: Outflows, Time-Lags And Echoes Unveiled, S. Scaringi, T. J. Maccarone, R. I. Hynes, E. Körding, G. Ponti, C. Knigge, C. T. Britt, H. Van Winckel
Sco X-1 Revisited With Kepler, Maxi And Hermes: Outflows, Time-Lags And Echoes Unveiled, S. Scaringi, T. J. Maccarone, R. I. Hynes, E. Körding, G. Ponti, C. Knigge, C. T. Britt, H. Van Winckel
Faculty Publications
Sco X-1 has been the subject of many multiwavelength studies in the past, being the brightest persistent extrasolar X-ray source ever observed. Here, we revisit Sco X-1 with simultaneous short cadence Kepler optical photometry and Monitor of All-sky X-ray Image X-ray photometry over a 78 d period, as well as optical spectroscopy obtained with High Efficiency and ResolutionMercator Echelle Spectrograph (HERMES).We find Sco X-1 to be highly variable in all our data sets. The optical fluxes are clearly bimodal, implying the system can be found in two distinct optical states. These states are generally associated with the known flaring/normal branch …
Variability Of Optical Counterparts In The Chandra Galactic Bulge Survey, C. T. Britt, R. I. Hynes, C. B. Johnson, A. Baldwin, P. G. Jonker, G. Nelemans, M. A.P. Torres, T. Maccarone, D. Steeghs, S. Greiss, C. Heinke, C. G. Bassa, A. Collazzi, A. Villar, M. Gabb, L. Gossen
Variability Of Optical Counterparts In The Chandra Galactic Bulge Survey, C. T. Britt, R. I. Hynes, C. B. Johnson, A. Baldwin, P. G. Jonker, G. Nelemans, M. A.P. Torres, T. Maccarone, D. Steeghs, S. Greiss, C. Heinke, C. G. Bassa, A. Collazzi, A. Villar, M. Gabb, L. Gossen
Faculty Publications
We present optical light curves of variable stars consistent with the positions of X-ray sources identified with the Chandra X-ray Observatory for the Chandra Galactic Bulge Survey (GBS). Using data from the Mosaic-II instrument on the Blanco 4 m Telescope at CTIO, we gathered time-resolved photometric data on timescales from ∼2 hr to 8 days over the 3/4 of the X-ray survey containing sources from the initial GBS catalog. Among the light curve morphologies we identify are flickering in interacting binaries, eclipsing sources, dwarf nova outbursts, ellipsoidal variations, long period variables, spotted stars, and flare stars. Eighty-seven percent of X-ray …
The Galactic Bulge Survey: Completion Of The X-Ray Survey Observations, Peter G. Jonker, Manuel A.P. Torres, Robert I. Hynes, Thomas J. Maccarone, Danny Steeghs, Sandra Greiss, Christopher T. Britt, Jianfeng Wu, Christopher B. Johnson, Gijs Nelemans, Craig Heinke
The Galactic Bulge Survey: Completion Of The X-Ray Survey Observations, Peter G. Jonker, Manuel A.P. Torres, Robert I. Hynes, Thomas J. Maccarone, Danny Steeghs, Sandra Greiss, Christopher T. Britt, Jianfeng Wu, Christopher B. Johnson, Gijs Nelemans, Craig Heinke
Faculty Publications
We provide the Chandra source list for the last quarter of the area covered by the Galactic Bulge Survey (GBS). The GBS targets two strips of 6° × 1° (12 square degrees in total), one above (1° < b < 2°) and one below (-2° < b < -1°) the Galactic plane in the direction of the Galactic center at X-ray, optical, and near-infrared wavelengths. For the X-ray part of the survey we use 2 ks per Chandra pointing. We find 424 X-ray sources in the 63 Chandra observations on which we report here. These sources are in addition to the 1216 X-ray sources discovered in the first part of the GBS survey described previously. We discuss the characteristics and the X-ray variability of the brightest of the sources as well as the radio properties from existing radio surveys. We point out an interesting asymmetry in the number of X-ray sources as a function of their Galactic l and b coordinates which is probably caused by differences in average extinction toward the different parts of the GBS survey area. © 2014. The American Astronomical Society. All rights reserved..
Multiwavelength Observations Of Swift J1753.5-0127, Cynthia S. Froning, Thomas J. Maccarone, Kevin France, Lisa Winter, Edward L. Robinson, Robert I. Hynes, Fraser Lewis
Multiwavelength Observations Of Swift J1753.5-0127, Cynthia S. Froning, Thomas J. Maccarone, Kevin France, Lisa Winter, Edward L. Robinson, Robert I. Hynes, Fraser Lewis
Faculty Publications
We present contemporaneous X-ray, ultraviolet (UV), optical, and near-infrared observations of the black hole binary system Swift J1753.5-0127 acquired in 2012 October. The UV observations, obtained with the Cosmic Origins Spectrograph on the Hubble Space Telescope, are the first UV spectra of this system. The dereddened UV spectrum is characterized by a smooth, blue continuum and broad emission lines of C IV and He II. The system was stable in the UV to <10% during our observations. We estimated the interstellar reddening by fitting the 2175 Å absorption feature and fit the interstellar absorption profile of Lyα to directly measure the neutral hydrogen column density along the line of sight. By comparing the UV continuum flux to steady-state thin accretion disk models, we determined upper limits on the distance to the system as a function of black hole mass. The continuum is well fit with disk models dominated by viscous heating rather than irradiation. The broadband spectral energy distribution shows the system has declined at all wavelengths since previous broadband observations in 2005 and 2007. If we assume that the UV emission is dominated by the accretion disk, the inner radius of the disk must be truncated at radii above the innermost stable circular orbit to be consistent with the X-ray flux, requiring significant mass loss from outflows and/or energy loss via advection into the black hole to maintain energy balance. © 2014. The American Astronomical Society. All rights reserved.
Cxogbs J174444.7-260330: A New Long Orbital Period Cataclysmic Variable In A Low State, E. M. Ratti, T. F.J. Van Grunsven, P. G. Jonker, C. T. Britt, R. I. Hynes, D. Steeghs, S. Greiss, M. A.P. Torres, T. J. Maccarone, P. J. Groot, C. Knigge, L. Gossen, V. Mikles, V. A. Villar, A. C. Collazzi
Cxogbs J174444.7-260330: A New Long Orbital Period Cataclysmic Variable In A Low State, E. M. Ratti, T. F.J. Van Grunsven, P. G. Jonker, C. T. Britt, R. I. Hynes, D. Steeghs, S. Greiss, M. A.P. Torres, T. J. Maccarone, P. J. Groot, C. Knigge, L. Gossen, V. Mikles, V. A. Villar, A. C. Collazzi
Faculty Publications
We present phase-resolved spectroscopy and photometry of a source discovered with the Chandra Galactic Bulge Survey (GBS), CXOGBS J174444.7-260330 (aka CX93 and CX153 in the previously published GBS list). We find two possible values for the orbital period P, differing from each other by ~13 s. The most likely solution is P = 5.690 14(6) h. The optical lightcurves show ellipsoidal modulations, whose modelling provides an inclination of 32±1° for the most likely P. The spectra are dominated by a K5 V companion star (the disc veiling is 5 per cent). Broad and structured emission from the Balmer lines is …
Tearing Up The Disk: How Black Holes Accrete, Chris Nixon, Andrew King, Daniel Price, Juhan Frank
Tearing Up The Disk: How Black Holes Accrete, Chris Nixon, Andrew King, Daniel Price, Juhan Frank
Faculty Publications
We show that in realistic cases of accretion in active galactic nuclei or stellar-mass X-ray binaries, the Lense-Thirring effect breaks the central regions of tilted accretion disks around spinning black holes into a set of distinct planes with only tenuous flows connecting them. If the original misalignment of the outer disk to the spin axis of the hole is 45° ≲ θ ≲ 135°, as in 70% of randomly oriented accretion events, the continued precession of these disks sets up partially counterrotating gas flows. This drives rapid infall as angular momentum is canceled and gas attempts to circularize at smaller …
X-Ray And Optical Observations Of A0535+26, A. Camero-Arranz, M. H. Finger, C. A. Wilson-Hodge, P. Jenke, I. Steele, M. J. Coe, J. Gutierrez-Soto, P. Kretschmar, I. Caballero, J. Yan, J. Rodríguez, J. Suso, G. Case, M. L. Cherry, S. Guiriec, V. A. Mcbride
X-Ray And Optical Observations Of A0535+26, A. Camero-Arranz, M. H. Finger, C. A. Wilson-Hodge, P. Jenke, I. Steele, M. J. Coe, J. Gutierrez-Soto, P. Kretschmar, I. Caballero, J. Yan, J. Rodríguez, J. Suso, G. Case, M. L. Cherry, S. Guiriec, V. A. Mcbride
Faculty Publications
We present recent contemporaneous X-ray and optical observations of the Be/X-ray binary system A0535+26 with the Fermi/Gamma-ray Burst Monitor (GBM) and several ground-based observatories. These new observations are put into the context of the rich historical data (since ∼1978) and discussed in terms of the neutron-star-Be-disk interaction. The Be circumstellar disk was exceptionally large just before the 2009 December giant outburst, which may explain the origin of the unusual recent X-ray activity of this source. We found a peculiar evolution of the pulse profile during this giant outburst, with the two main components evolving in opposite ways with energy. A …
Optical And Infrared Light Curves Of The Eclipsing X-Ray Binary V395 Car = 2s 0921-630, T. A. Ashcraft, R. I. Hynes, E. L. Robinson
Optical And Infrared Light Curves Of The Eclipsing X-Ray Binary V395 Car = 2s 0921-630, T. A. Ashcraft, R. I. Hynes, E. L. Robinson
Faculty Publications
We present results of optical and infrared photometric monitoring of the eclipsing low-mass X-ray binary V395 Car (2S 0921-630). Our observations reveal a clear, repeating orbital modulation with an amplitude of about 1 mag in B and V, and a little less in J. Combining our data with archival observations spanning about 20years, we derive an updated ephemeris with orbital period 9.0026 ± 0.0001d. We attribute the modulation to a combination of the changing aspect of the irradiated face of the companion star and eclipses of the accretion disc around the neutron star. Both appear to be necessary as a …
Fitting Along The Fundamental Plane: New Comparisons Of Jet Physics Across The Black Hole Mass Scale, Sera Markoff, Michael A. Nowak, Dipankar Maitra, Jörn Wilms, Elena Gallo, Robert Hynes, Richard Plotkin
Fitting Along The Fundamental Plane: New Comparisons Of Jet Physics Across The Black Hole Mass Scale, Sera Markoff, Michael A. Nowak, Dipankar Maitra, Jörn Wilms, Elena Gallo, Robert Hynes, Richard Plotkin
Faculty Publications
Correlations between the radio and X-ray bands in the hard state of black hole X-ray binaries (BHBs) have led to the discovery of the Fundamental Plane of black hole accretion, linking accretion-driven radiative attributes to black hole mass. Although this discovery has led to new constraints on radiative efficiencies, there is still significant degeneracy in terms of understanding the governing physics. I present several new results exploring the processes driving the Fundamental Plane over the black hole mass range. These include the first ever homogeneous fits of sources at approximately the same Eddington luminosity but millions of times different in …
The Complete Spectrum Of The Neutron Star X-Ray Binary 4u 0614+091, S. Migliari, J. A. Tomsick, J. C.A. Miller-Jones, S. Heinz, R. I. Hynes, R. P. Fender, E. Gallo, P. G. Jonker, T. J. Maccarone
The Complete Spectrum Of The Neutron Star X-Ray Binary 4u 0614+091, S. Migliari, J. A. Tomsick, J. C.A. Miller-Jones, S. Heinz, R. I. Hynes, R. P. Fender, E. Gallo, P. G. Jonker, T. J. Maccarone
Faculty Publications
We observed the neutron star (NS) ultra-compact X-ray binary 4U 0614+091 quasi-simultaneously in the radio band (Very Large Array), mid-infrared (IR)/IR (Spitzer/Multiband Imaging Photometer for Spitzer and Infrared Array Camera), near-IR/optical (Small and Moderate Aperture Research Telescope System), optical-UV (Swift/UV-Optical Telescope), soft and hard X-rays (Swift/X-ray Telescope and Rossi-X-ray Timing Explorer). The source was steadily in its "hard state." We detected the source in the whole range, for the first time in the radio band at 4.86 and 8.46GHz and in the mid-IR at 24 μm, up to 100 keV. The optically thick synchrotron spectrum of the jet is consistent …
The Quiescent Spectral Energy Distribution Of V404 Cyg, R. I. Hynes, C. K. Bradley, M. Rupen, E. Gallo, R. P. Fender, J. Casares, C. Zurita
The Quiescent Spectral Energy Distribution Of V404 Cyg, R. I. Hynes, C. K. Bradley, M. Rupen, E. Gallo, R. P. Fender, J. Casares, C. Zurita
Faculty Publications
We present a multiwavelength study of the black hole X-ray binary V404 Cyg in quiescence, focusing upon the spectral energy distribution (SED). Radio, optical, ultraviolet (UV) and X-ray coverage is simultaneous. We supplement the SED with additional non-simultaneous data in the optical through infrared where necessary. The compiled SED is the most complete available for this, the X-ray and radio brightest quiescent black hole system. We find no need for a substantial contribution from accretion light from the near-UV to the near-IR, and in particular the weak UV emission constrains published spectral models for V404 Cyg. We confirm that no …
Echo Mapping Of Swift J1753.5-0127, R. I. Hynes, K. O. Brien, F. Mullally, T. Ashcraft
Echo Mapping Of Swift J1753.5-0127, R. I. Hynes, K. O. Brien, F. Mullally, T. Ashcraft
Faculty Publications
We present two epochs of coordinated X-ray-optical timing observations of the black hole candidate Swift J1753.5-0127 during its 2005 outburst. The first epoch in July occurred at outburst peak. Two consecutive nights of observations using the McDonald Observatory Argos camera with the Rossi X-ray Timing Explorer show a consistent correlation with an immediate response and an extended tail lasting ∼5 s. The properties of the variability and the correlation are consistent with thermal reprocessing in an accretion disc. The shortness of the lag suggests a short orbital period consistent with that recently claimed. The second epoch in August used the …
An Anticorrelation Between X-Ray Luminosity And Hα Equivalent Width In X-Ray Binaries, R. P. Fender, D. M. Russell, C. Knigge, R. Soria, R. I. Hynes, M. Goad
An Anticorrelation Between X-Ray Luminosity And Hα Equivalent Width In X-Ray Binaries, R. P. Fender, D. M. Russell, C. Knigge, R. Soria, R. I. Hynes, M. Goad
Faculty Publications
We report an anticorrelation between continuum luminosity and the equivalent width (EW) of the Hα emission line in X-ray binary systems. The effect is evident both in a universal monotonic increase in Hα EW with time following outbursts, as systems fade, and in a comparison between measured EWs and contemporaneous X-ray measurements. The effect is most clear for black hole binaries in the low/hard X-ray state, which is prevalent at X-ray luminosities below ∼1 per cent of the Eddington luminosity. We do not find strong evidence for significant changes in line profiles across accretion state changes, but this is hampered …
The Orbital Period And Time-Variable Asymmetric Accretion Disk In The X-Ray Binary-Ms 1603.6+2600 (=Uw Coronae Borealis), Paul A. Mason, Edward L. Robinson, Candace L. Gray, Robert I. Hynes
The Orbital Period And Time-Variable Asymmetric Accretion Disk In The X-Ray Binary-Ms 1603.6+2600 (=Uw Coronae Borealis), Paul A. Mason, Edward L. Robinson, Candace L. Gray, Robert I. Hynes
Faculty Publications
We present CCD photometry of the low-mass X-ray binary UW Coronae Borealis (UW CrB). Its light curve shows eclipses at a period near 111 minutes, but the eclipses vary in depth and shape and often disappear. Restricting our analysis to the deeper eclipses, we find the orbital period to be 110.976722 ± 0.000012 minutes, but the times of mideclipse can deviate by more than 0.025 in phase from the best-fit ephemeris. There is an additional large-amplitude variation with a period of 112.58 ± 0.03 minutes reminiscent of the superhumps seen in the light curves of some cataclysmic variables. The variations …
A Signature Of The Donor Star In The Extra-Galactic X-Ray Binary Lmc X-2, R. Cornelisse, D. Steeghs, J. Casares, P. A. Charles, I. C. Shih, R. I. Hynes, K. O'Brien
A Signature Of The Donor Star In The Extra-Galactic X-Ray Binary Lmc X-2, R. Cornelisse, D. Steeghs, J. Casares, P. A. Charles, I. C. Shih, R. I. Hynes, K. O'Brien
Faculty Publications
Two nights of phase-resolved medium-resolution Very Large Telescope spectroscopy of the extra-galactic low-mass X-ray binary LMC X-2 have revealed a 0.32 ± 0.02 d spectroscopic period in the radial velocity curve of the He ii λ4686 emission line that we interpret as the orbital period. However, similar to previous findings, this radial velocity curve shows a longer term variation that is most likely due to the presence of a precessing accretion disc in LMC X-2. This is strengthened by He ii λ4686 Doppler maps that show a bright spot that is moving from night to night. Furthermore, we detect narrow …
Optical Spectroscopy Of The Low-Mass X-Ray Binary Gx 9+9, R. Cornelisse, D. Steeghs, J. Casares, P. A. Charles, A. D. Barnes, R. I. Hynes, K. O'Brien
Optical Spectroscopy Of The Low-Mass X-Ray Binary Gx 9+9, R. Cornelisse, D. Steeghs, J. Casares, P. A. Charles, A. D. Barnes, R. I. Hynes, K. O'Brien
Faculty Publications
Phase-resolved medium-resolution VLT spectroscopy of the low-mass X-ray binary GX 9+9 has revealed narrow C iii emission lines that move in phase relative to our new estimate of the ephemeris, and show a velocity amplitude of 230 ± 35 km s-1. We identify the origin of these lines as coming from the surface of the donor star, thereby providing the first estimate of the mass function of f(M1) ≥ 0.22 M⊙. Rotational broadening estimates together with assumptions for the mass donor give 0.07 ≤ q ≤ 0.35 and 182 ≤ K2 ≤ 406 km s -1. Despite a low-mass ratio, …
A Detection Of The Donor Star Of Aquila X-1 During Its 2004 Outburst?, R. Cornelisse, J. Casares, D. Steeghs, A. D. Barnes, P. A. Charles, R. I. Hynes, K. O'Brien
A Detection Of The Donor Star Of Aquila X-1 During Its 2004 Outburst?, R. Cornelisse, J. Casares, D. Steeghs, A. D. Barnes, P. A. Charles, R. I. Hynes, K. O'Brien
Faculty Publications
Phase-resolved high-resolution optical spectroscopy has revealed narrow N III and He II emission lines from the soft X-ray transient Aquila X-1 during its 2004 outburst that move as a function of the orbit consistent with the phasing of the donor star. Under the assumption that these lines come from the irradiated side of the donor star, we can constrain its K2 velocity to ≥247 ± 8 kms-1 and derive a mass function of f(M 1) ≥ 1.23 ± 0.12M⊙. Estimates for the rotational broadening based on the emission components suggest a possible massive neutron star of ≥ 1.6M⊙ (at 95 …