Publications
Refereed
- 7) Suzaku broadband spectroscopy of Swift J1753.5-0127 in the Low-Hard
State
Mark Reynolds, Jon Miller, Jeroen Homan, Giovanni
Miniutti, arXiv:0911.3642 (ApJ accepted)
- 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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.pdf here
- 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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notices .pdf here
- 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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notices .pdf here
- 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.
Get the monthly notices
.pdf here.
- 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.
Get the monthly notices
.pdf here.
Conference Proceedings
- 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 #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