Mark Reynolds

Publications

Refereed

16) A Swift Survey of Accretion onto Stellar Mass Black Holes
Mark Reynolds, Jon Miller, 2011, ApJ submitted (arXiv:1112.2249): We present a systemic analysis of all of the stellar mass black hole binaries (confirmed & candidate) observed by the Swift observatory up to June 2010. The broad Swift bandpass enables a trace of disk evolution over an unprecedented range in flux and temperature. The final data sample consists of 476 X-ray spectra containing greater than 100 counts, in the 0.6 – 10 keV band. This is the largest sample of high quality CCD spectra of accreting black holes published to date. In addition, strictly simultaneous data at optical/UV wavelengths are available for 255 (54%) of these observations. The data are modelled with a combination of an accretion disk and a hard spectral component. For the hard component we consider both a simple power-law and a thermal Comptonization model. An accretion disk is detected at greater than the 5σ confidence level in 61% of the observations. Lightcurves and color-color diagrams are constructed for each system. Hardness luminosity and disk fraction luminosity diagrams are constructed and are observed to be consistent with those typically observed by RXTE, noting the sensitivity below 2 keV provided by Swift. The observed spectra have an average luminosity of ~ 1% Eddington, though we are sensitive to accretion disks down to a luminosity of 10−3 LEdd. Thus this is also the largest sample of such cool accretion disks studied to date. (Abridged)
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15) Suzaku Observation of the Black Hole Candidate MAXI J1836-194 in a Hard/Intermediate Spectral State
Rubens Reis, Jon Miller, Mark Reynolds, Andrew Fabian, Dominic Walton, 2011, ApJ submitted (arXiv:1111.6665): We report on a Suzaku observation of the newly discovered X-ray binary MAXI J1836-194. The source is found to be in the hard/intermediate spectral state and displays a clear and strong relativistically broadened iron emission line. We fit the spectra with a variety of phenomenological, as well as physically motivated disk reflection models, and find that the breadth and strength of the iron line are always characteristic of emission within a few gravitational radii around a black hole. This result is independent of the continuum used and strongly points toward the central object in MAXI J1836-194 being a stellar mass black hole rotating with a spin of a=0.86 \pm 0.04 (90% confidence). We discuss this result in the context of spectral state definitions, physical changes (or lack thereof) in the accretion disk and on the potential importance of the accretion disk corona in state transitions.
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14) Multimessenger Astronomy with Pulsar Timing and X-ray Observations of Massive Black Hole Binaries
Alberto Sesana, Constanze Roedig, Mark Reynolds, Massimo Dotti, 2012, MNRAS, 420, 860: We demonstrate that very massive (>10^8\msun), cosmologically nearby (z<1) black hole binaries (MBHBs), which are primary targets for ongoing and upcoming pulsar timing arrays (PTAs), are particularly appealing multimessenger carriers. According to current models for massive black hole formation and evolution, the planned Square Kilometer Array (SKA) will collect gravitational wave signals from thousands of such massive systems, being able to individually resolve and locate in the sky several of them (maybe up to a hundred). By employing a standard model for the evolution of MBHBs in circumbinary discs, with the aid of dedicated numerical simulations, we characterize the gas-binary interplay, identifying possible electromagnetic signatures of the PTA sources. We concentrate our investigation on two particularly promising scenarios in the high energy domain, namely, the detection of X-ray periodic variability and of double broad K\alpha iron lines. Up to several hundreds of periodic X-ray sources with a flux >10^-13 erg s^-1 cm^-2 will be in the reach of upcoming X-ray observatories. Double relativistic K\alpha lines may be observable in a handful of low redshift (z<0.3) sources by proposed deep X-ray probes, such as Athena. (Abridged)
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13) A strong emission line near 24.8 angstrom in the X-ray binary system MAXI J0556--332: gravitational redshift or unusual donor?
Dipankar Maitra, Jon Miller, John Raymond, Mark Reynolds, 2011, ApJ, 743, 11: We report the discovery of a strong emission line near 24.8 angstrom (0.5 keV) in the newly discovered X-ray binary system MAXI J0556-332 with the reflection grating spectrometer onboard the XMM-Newton observatory. The X-ray light curve morphology during these observations is complex and shows occasional dipping behavior. Here we present time- and rate-selected spectra from the RGS and show that this strong emission line is unambiguously present in all the XMM observations. The measured line center is consistent with the Ly-alpha transition of N VII in the rest frame. While the spectra contain imprints of absorption lines and edges, there appear to be no other significantly prominent narrow line due to the source itself, thus making the identification of the 24.8 angstrom line uncertain. We discuss possible physical scenarios, including a gravitationally redshifted O VIII Ly-alpha line originating at the surface of a neutron star or an unusual donor with an extremely high N/O abundance (>57) relative to solar, that may have produced this comparatively strong emission line.
Get the astrophysical journal .pdf here.
12) An Anomalous Quiescent Stellar Mass Black Hole
Mark Reynolds, Jon Miller, 2011, ApJ, 734, 17: We present the results of a 40 ks Chandra observation of the quiescent stellar mass black hole GS 1354-64. A total of 266 net counts are detected at the position of this system. The resulting spectrum is found to be consistent with the spectra of previously observed quiescent black holes, i.e., a power-law with a photon index of Γ ∼ 2. The inferred luminosity in the 0.5 -- 10 keV band is found to lie in the range 0.5 - 6.5 x 10^{34} erg/s, where the uncertainty in the distance is the dominant source of this large luminosity range. Nonetheless, this luminosity is over an order of magnitude greater than that expected from the known distribution of quiescent stellar mass black hole luminosities and makes GS 1354-64 the only known stellar mass black hole to disagree with this relation. This observation suggests the possibility of significant accretion persisting in the quiescent state.
Get the astrophysical journal .pdf here.
11) Ground- and space-based study of two globular cluster cataclysmic variables: M22 CV1 and M5 V101
Anna Hourihane, Paul Callanan, Adrienne Cool, Mark Reynolds, 2011, MNRAS, 414, 184: As a class of compact binaries with large binding energy, cataclysmic variables (CVs) formed through close encounters play an important role in the dynamical evolution of globular clusters. As part of a systematic search for CVs undergoing dwarf nova (DN) eruptions in globular clusters, our 2004 monitoring programme of M22 detected an outburst of the DN candidate CV1 during May. We implement the ISIS image subtraction routine to obtain a light curve for an outburst of CV1. We present the outburst light curve as well as Hubble Space Telescope/Wide-Field Planetary Camera 2 (WFPC2) photometry in the V, U and near-ultraviolet (nUV) bands and a Chandra/Advanced CCD Imaging Spectrometer (ACIS) spectrum of the object. Our results confirm the DN nature of the outburst and the CV status of the object. We also present the results of a ground-based study of another globular cluster CV, M5 V101 - including quiescent medium-resolution William Herschel Telescope (WHT)/Intermediate dispersion Spectrograph and Imaging System (ISIS) spectroscopy in the B and R bands, displaying prominent Balmer and He I emission, and R-band photometry.
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10) A Distinctive Disk-Jet Coupling in the Seyfert-1 AGN NGC 4051
Ashley King, Jon Miller, Edward Cackett, Andy Fabian, Micheal Nowak, Micheal Rupen, Kayhan Gultekin, Mark Reynolds, 2011, ApJ, 729, 19: We report on the results of a simultaneous monitoring campaign employing eight Chandra X-ray (0.5-10 keV) and six VLA/EVLA (8.4 GHz) radio observations of NGC 4051 over seven months. Evidence for compact jets is observed in the 8.4 GHz radio band; This builds on mounting evidence that jet production may be prevalent even in radio-quiet Seyferts. Assuming comparatively negligible local diffuse emission in the nucleus, the results also demonstrate an inverse correlation of L_radio proportional to L_X-ray ^(-0.72+/-0.04) . Current research linking the mass of supermassive black holes and stellar-mass black holes in the "low/hard" state to X-ray luminosities and radio luminosities suggest a "fundamental plane of accretion onto black holes" that has a positive correlation of L_radio proportional to L_X-ray^(0.67+/-0.12) . Our simultaneous results differ from this relation by more than 11 sigma, indicating that a separate mode of accretion and ejection may operate in this system. A review of the literature shows that the inverse correlation seen in NGC 4051 is seen in three other black hole systems, all of which accrete at near 10% of their Eddington luminosity, perhaps suggesting a distinct mode of disk-jet coupling at high Eddington fractions. We discuss our results in the context of disk and jets in black holes and accretion across the black hole mass scale.
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9) Chandra grating spectroscopy of the Be/X-ray binary 1A 0535+262
Mark Reynolds, Jon Miller, 2010, ApJ, 723, 1799: We present Chandra HETGS spectroscopy of the Be/X-ray binary 1A 0535+262 obtained during the 2009/2010 giant outburst. These are the first CCD grating spectra of this type of system during a giant outburst. Our spectra reveal a number of lines including a narrow Fe K_alpha emission line with a FWHM of ~ 5000 km s^-1. For the first time, we detect the presence of a highly ionized outflow in a Be/X-ray binary. Assuming that the line is He-like Fe XXV, fits with a simple Gaussian imply an outflow velocity of ~ 1500 km s^-1. However, self-consistent photoionization modeling with XSTAR suggests that Fe XXIII-XXIV must also contribute. In this case, an outflow velocity of ~ 3000 km s^-1 is implied. These results are discussed in the context of the accretion flow in Be-star, neutron star, and black hole X-ray binaries.
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8) Suzaku Observations of the Galactic Center Microquasar 1E 1740.7-2942
Mark Reynolds, Jon Miller, 2010, ApJ, 716, 1431: We present two Suzaku observations of the Galactic center microquasar 1E 1740.7-2942 separated by approximately 700 days. The source was observed on both occasions after a transition to the spectrally hard state. Significant emission from 1E 1740.7-2942 is detected out to an energy of 300 keV, with no spectral break or turnover evident in the data. We tentatively measure a lower limit to the cut-off energy of ~ 380 keV. The spectra are found to be consistent with a Comptonized corona on both occasions, where the high energy emission is consistent with a hard power-law (\Gamma ~ 1.8) with a significant contribution from an accretion disc with a temperature of ~ 0.4 keV at soft X-ray energies. The measured value for the inner radius of the accretion disc is found to be inconsistent with the picture whereby the disc is truncated at large radii in the low-hard state and instead favours a radius close to the ISCO (R_in ~ 10 - 20 R_g).
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7) Suzaku broadband spectroscopy of Swift J1753.5-0127 in the Low-Hard State
Mark Reynolds, Jon Miller, Jeroen Homan, Giovanni Miniutti, 2010, ApJ, 709, 358: We present Suzaku observations of the Galactic black hole candidate Swift J1753.5-0127 in the low-hard state. The broadband coverage of Suzaku enables us to detect the source over the energy range 0.6 -- 250 keV. The broadband spectrum (2 -- 250 keV) is found to be consistent with a simple power-law (gamma \sim 1.63). In agreement with previous observations of this system, a significant excess of soft X-ray flux is detected consistent with the presence of a cool accretion disc. Estimates of the disc inner radius infer a value consistent with the ISCO (R_{in} \lesssim 6 R_g, for certain values of, e.g. N_H, i), although we cannot conclusively rule out the presence of an accretion disc truncated at larger radii (R_{in} \sim 10 - 50 R_g). A weak, relativistically-broadened iron line is also detected, in addition to disc reflection at higher energy. However, the iron-K line profile favours an inner radius larger than the ISCO (R _{in} \sim 10 - 20 R_g). The implications of these observations for models of the accretion flow in the low-hard state are discussed.
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6) A photometric study of the field around the candidate recoiling/binary black hole SDSS J092712.65+294344.0
Roberto Decarli, Mark Reynolds, Massimo Dotti, 2009, MNRAS, 397, 458: We present a photometric FUV to Ks-band study of the field around quasar SDSS J092712.65+294344.0. The SDSS spectrum of this object shows various emission lines with two distinct redshifts, at z=0.699 and z=0.712. Because of this peculiar spectroscopic feature this source has been proposed as a candidate recoiling or binary black hole. A third alternative model involves two galaxies moving in the centre of a rich galaxy cluster. Here we present a study addressing the possible presence of such a rich cluster of galaxies in the SDSS J092712.65+294344.0 field. We observed the 3.6x2.6 square arcmin field in the Ks-band and matched the NIR data with the FUV and NUV images in the GALEX archive and the ugriz observations in the SDSS. From various colour-colour diagrams we were able to classify the nature of 32 sources, only 6-11 of which have colours consistent with galaxies at z~0.7. We compare these numbers with the surface density of galaxies, stars & quasars, and the expectations for typical galaxy clusters both at low and high redshift. Our study shows that the galaxy cluster scenario is in clear disagreement with the new observations.
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5) Broad Relativistic Iron Line Emission Observed in SAX J1808.4-3658
Edward Cackett, Diego Altamirano, Alessandro Patruno, Jon Miller, Mark Reynolds, Manuel Linares, Rudy Wijnands, 2009, ApJ, 694, 21: During the September-October 2008 outburst of the accreting millisecond pulsar SAX J1808.4-3658, the source was observed by both Suzaku and XMM-Newton approximately 1 day apart. Spectral analysis reveals a broad relativistic Fe K-alpha emission line which is present in both data-sets, as has recently been reported for other neutron star low-mass X-ray binaries. The properties of the Fe K line observed during each observation are very similar. From modeling the Fe line, we determine the inner accretion disk radius to be 13.2 +/- 2.5 GM/c^2. The inner disk radius measured from the Fe K line suggests that the accretion disk is not very receded in the island state. If the inner disk (as measured by the Fe line) is truncated at the magnetospheric radius this implies a magnetic field strength of ~3E8 G at the magnetic poles, consistent with other independent estimates.
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4) Optical Spectroscopy and Photometry of SAX J1808.4-3658 in Outburst
Patrick Elebert, Mark Reynolds, Paul Callanan, Dan Hurley, Gavin Ramsay, Fraser Lewis, Dave Russell, Brian Nord, Stephen Kane, D. LePoy, Pasi Hakala, 2009, MNRAS, 395, 884: We present phase resolved optical spectroscopy and photometry of V4580 Sagittarii, the optical counterpart to the accretion powered millisecond pulsar SAX J1808.4-3658, obtained during the 2008 September/October outburst. Doppler tomography of the N III 4640.64 Bowen blend emission line reveals a focused spot of emission at a location consistent with the secondary star. The velocity of this emission occurs at 324 +/- 15 km/s; applying a "K-correction", we find the velocity of the secondary star projected onto the line of sight to be 370 +/- 40 km/s. Based on existing pulse timing measurements, this constrains the mass ratio of the system to be 0.044^{+0.005}_{-0.004}, and the mass function for the pulsar to be 0.44^{+0.16}_{-0.13} Msun. Combining this mass function with various inclination estimates from other authors, we find no evidence to suggest that the neutron star in SAX J1808.4-3658 is more massive than the canonical value of 1.4 Msun. Our optical light curves exhibit a possible superhump modulation, expected for a system with such a low mass ratio. The equivalent width of the Ca II H and K interstellar absorption lines suggest that the distance to the source is ~2.5 kpc. This is consistent with previous distance estimates based on type-I X-ray bursts which assume cosmic abundances of hydrogen, but lower than more recent estimates which assume helium-rich bursts.
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3) IR Contamination in Galactic XRNe
Mark Reynolds, Paul Callanan, Edward Robinson, Cynthia Froning, 2008, MNRAS, 387, 788: The most widely used means of measuring the mass of black holes in Galactic binaries - specifically the X-ray novae - involves both radial velocity measurements of the secondary star, and photometric measurements of its ellipsoidal variability. The latter is important in constraining the inclination and mass ratio, and requires as direct a measure of the flux of the secondary as possible. Up to now, such measurements have been preferentially carried out in the NIR (1 -- 2.5$\mu m$), where the flux from the cooler secondary is expected to dominate over that from the accretion disc. However, here we present evidence of a significant non-stellar contribution to the NIR flux in many of those quiescent X-ray novae that are thought to contain a black hole primary. We discuss origins of this excess and the effect of such contamination on Galactic black hole mass measurements.
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2) The Light Curve of the Companion to PSR B1957+20
Mark Reynolds, Paul Callanan, Andy Fruchter, Manuel Torres, Martin Beer, Rachel Gibbons, 2007, MNRAS, 379, 1117: We present a new analysis of the light curve for the secondary star in the eclipsing binary millisecond pulsar system PSR B1957+20. Combining previous data and new data points at minimum from the Hubble Space Telescope, we have 100% coverage in the R-band. We also have a number of new K_s-band data points, which we use to constrain the infrared magnitude of the system. We model this with the Eclipsing Light Curve code (ELC). From the modelling with the ELC code we obtain colour information about the secondary at minimum light in BVRI and K. For our best fit model we are able to constrain the system inclination to 65 +/- 2 degrees for pulsar masses ranging from 1.3 -- 1.9 M_sun. The pulsar mass is unconstrained. We also find that the secondary star is not filling its Roche lobe. The temperature of the un-irradiated side of the companion is in agreement with previous estimates and we find that the observed temperature gradient across the secondary star is physically sustainable.
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1) Keck K-band Observations of GRO J0422+32
Mark Reynolds, Paul Callanan, Alex Filippenko, 2007, MNRAS, 374, 657: We present Keck K-band photometry and low-resolution H & K-band spectroscopy of the X-ray nova GRO J0422+32 obtained while the system was in the quiescent state. No clear ellipsoidal modulation is present in the light curve, which is instead dominated by a strong flickering component. In the K-band we observe strong Br_gamma emission, with an equivalent width of 38 +/- 5 Angstroms. From this we conclude that the accretion disc is the most likely source of the observed photometric contamination, and that previous infrared-based attempts to constrain the mass of the putative black hole in this system are prone to considerable uncertainty. We finally proceed to show how it is possible to place meaningful constraints on some of the binary parameters of this system, even in the presence of a relatively high level of contamination from the disc.
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Conference Proceedings

The Swift Galactic Plane Survey: Mark Reynolds, Jon Miller, Dipankar Maitra, Kayhan Gultekin, Jamie Kennea, Mike Siegel, Neil Gehrels, Jonathon Gelbord, Paul Kuin
2011 High Energy Astrophysics Division meeting, Newport, Rhode Island, USA, 7th-10th September, 2011
The Jet and Windds in Seyfert-1 NGC 4051: Ashley King, Jon Miller, Andy Fabian, Ed Cackett, Sera Markoff, Mike Rupen, Kayhan Gultekin, Mark Reynolds, Mike Nowak, John Raymond
2011 High Energy Astrophysics Division meeting, Newport, Rhode Island, USA, 7th-10th September, 2011
Galactic X-Ray Binaries as observed by Swift: Mark Reynolds, Jon Miller
Swift Mission Conference Celebrating 5 Years, State College, Pennsylvania, USA, 18-20 November, 2009
The Nature of the Accretion Flow in the Low-Hard State: Mark Reynolds, Jon Miller
X-ray Astronomy 2009 Present status, multi-wavelength approach and future perspectives, Bologna, Italy, 7-11 September, 2009
Suzaku Observations of the Gacactic Center Microquasar 1E 1740.7-2942: Mark Reynolds, Jon Miller
X-ray Astronomy 2009 Present status, multi-wavelength approach and future perspectives, Bologna, Italy, 7-11 September, 2009
Suzaku Broadband Spectroscopy Of The Black Hole Candidate Swift J1753.5-0127: Mark Reynolds, Jon Miller, Jeroen Homan
2009, 213th meeting of the American Astronomical Society, Long Beach, California, 4-8 January
The Optical Counterparts of Binary Millisecond Pulsars in Quiescence: Paul Callanan, Mark Reynolds, Patrick Elebert, Alex Filippenko, Ryan Foley, Peter Garnavich, Glen Mackie
2006, 26th Texas Symposium on Relatavistic Astrophysics, Melbourne University, 11-15 December
On the Reliability of Galactic Black Hole Mass Estimates from Ellipsoidal IR Studies: Mark Reynolds, Paul Callanan
2006, 26th Texas Symposium on Relatavistic Astrophysics, Melbourne University, 11-15 December
IR Observations of Quiescent Black Hole XRNe: Mark Reynolds, Paul Callanan
Black Holes: From Stars to Galaxies - Across the Range of Masses, International Astronomical Union. Symposium no. 238, held 21-25 August, 2006 in Prague, Czech Republic, S238, 149
Optical Observations of Binary Millisecond X-ray Pulsars in Quiescence: Paul Callanan, Mark Reynolds, Alex Filippenko, Peter Garnavich, Ryan Foley
On the Present and Future of Pulsar Astronomy, 26th meeting of the IAU, Joint Discussion 2, 16-17 August, 2006, Prague, Czech Republic, JD02, 58
Keck IR Observation of GRO J0422+32 in Quiescence: Mark Reynolds, Paul Callanan, Alex Filippenko
2005, A Life with stars, A meeting in honour of the 65th birthday of Ed van den Heuvel, eds Kapers, van der Klis, Wijers
Optical Observations of IGR J00291+5934 in the Post Outburst Phase: Mark Reynolds, Patrick Elebert, Paul Callanan, Brian Field, Patrick Tuite, Manuel Torres, Danny Steeghs, Peter Garnavich, Don Terndrup, Alex Filippenko, Ryan Foley, Emilios Harlaftis
Populations of High Energy Sources in Galaxies Proceedings of the 230th Symposium of the International Astronomical Union, Held in Dublin, Ireland 15-19 August 2005, Edited by E. J. A. Meurs; G. Fabbiano. Cambridge: Cambridge University Press, 2006., pp.80-81
The Optical & IR Lightcurve of PSR B1957+20: Mark Reynolds, Paul Callanan, Andrew Fruchter, Manuel Torres, Martin Beer, Rachel Gibbons
Populations of High Energy Sources in Galaxies Proceedings of the 230th Symposi um of the International Astronomical Union, Held in Dublin, Ireland 15-19 August 2005, Edited by E. J. A. Meurs; G. Fabbiano. Cambridge: Cambridge University Press, 2006., pp.55-56
The Light Curve of the Companion to PSR B1957+20: Mark Reynolds, Paul Callanan, Andrew Fruchter, Manuel Torres, Martin Beer, Rachel Gibbons
INTERACTING BINARIES: Accretion, Evolution, and Outcomes. AIP Conference Proceedings, Volume 797, pp. 607-610

Circulars

Astronomer's Telegram #3415 -- Discovery of a New Supernova Remnant in the Swift Galactic Plane Survey: Jon Miller, Mark Reynolds, Dipankar Maitra, Kayhan Gultekin, Neil Gehrels, Jamie Kennea, Mike Siegel, Jonathon Gelbord, Paul Kuin
Astronomer's Telegram #3349 -- Discovery of a strong emission line at 0.5 keV in MAXI J0556-332 with the RGS on XMM-Newton: Dipankar Maitra, Mark Reynolds, Jon Miller, John Raymond
Astronomer's Telegram #3327 -- Rebrightening of MAXI J0556-332: Dipankar Maitra, Mark Reynolds, Peter Curran, Kayhan Gultekin, Jon Miller, Jamie Kennea, Dave Russell
Astronomer's Telegram #2744 -- X-ray, UV, Optical and NIR Observations of Aql X-1: Dipankar Maitra, Mark Reynolds, Jon M. Miller, Kayhan Gultekin
Astronomer's Telegram #2742 -- New X-ray Activity from Aql X-1: Kayhan Gultekin, Dipankar Maitra, Jon M. Miller Mark Reynolds
Astronomer's Telegram #2343 -- Swift XRT observation of 1A 0535+262: Mark Reynolds, Jon Miller
Astronomer's Telegram #2125 -- NIR Imaging of the Candidate Black Hole Transient XTE J1652-453: Mark Reynolds, Paul Callanan, Takahiro Nagayama
Astronomer's Telegram #1844 -- Broad relativistic iron line observed in SAX J1808.4-3658 by Suzaku: Edward Cackett, Diego Altamirano, Jon Miller, Mark Reynolds, Jennifer Blum, Manuel Linares, Alessandro Patruno, Rudy Wijnands
Astronomer's Telegram #1752 -- ESO VLT spectral observations of SAX J1808.4-3658 in outburst: Gavin Ramsay, Patrick Elebert, Paul Callanan, Mark Reynolds, Pasi Hakala
Astronomer's Telegram #1601 -- Possible near-infrared counterpart to the Galactic transient 1RXH J173523.7-354013: Edward Cackett, Rudy Wijnands, Mark Reynolds
Astronomer's Telegram #1110 -- Optical measurements of HETE J1900.1-2455 with the Large Binocular Telescope: Peter Garnavich, Paul Callanan, Patrick Elebert, Mark Reynolds