An evolving compact jet in the black hole X-ray binary MAXI J1836-194

M. Russell (IAC), T. D. Russell (Curtin), J. C. A. Miller-Jones (Curtin), K. O’Brien (Oxford), R. Soria (Curtin), G. R. Sivakoff (Alberta), T. Slaven-Blair (Curtin), F. Lewis (FT), S. Markoff (Amsterdam), J. Homan (MIT), D. Altamirano (Amsterdam), P. A. Curran (Curtin), M. P. Rupen (NRAO), T. M. Belloni (Brera), M. Cadolle Bel (ESAC), P. Casella (INAF), S. Corbel (CEA), V. Dhawan (NRAO), R. P. Fender (Southampton), E. Gallo (Michigan), P. Gandhi (JAXA, Durham), S. Heinz (Wisconsin-Madison), E. G. Kording (Nijmegen), H. A. Krimm (NASA GSFC, USRA), D. Maitra (Michigan), S. Migliari (Barcelona), R.A. Remillard (MIT), C. L. Sarazin(Virginia) , T. Shahbaz (IAC), V. Tudose (ASTRON)

We report striking changes in the broadband spectrum of the compact jet of the black hole transient MAXI J1836–194 over state transitions during its discovery outburst in 2011. A fading of the optical–infrared (IR) flux occurred as the source entered the hard–intermediate state, followed by a brightening as it returned to the hard state. The optical–IR spectrum was consistent with a power law from optically thin synchrotron emission, except when the X-ray spectrum was softest. By fitting the radio to optical spectra with a broken power law we constrain the frequency and flux of the optically thick/thin break in the jet synchrotron spectrum. The break gradually shifted to higher frequencies as the source hardened at X-ray energies, from 10¹¹ to  4×10¹³ Hz. The radiative jet luminosity integrated over the spectrum appeared to be greatest when the source entered the hard state during the outburst decay (although this is dependent on the high energy cooling break, which is not seen directly), even though the radio flux was fading at the time. The physical process responsible for suppressing and reactivating the jet (neither of which are instantaneous but occur on timescales of weeks) is uncertain, but could arise from the varying inner accretion disk radius regulating the fraction of accreting matter that is channeled into the jet This provides an unprecedented insight into the connection between inflow and outflow, and has implications for the conditions required for jets to be produced and hence their launching process.

Paper here

The optical counterpart of the bright X-ray transient Swift J1745-26

1. Muñoz-Darias (Southampton), A. de Ugarte Postigo (Andalucia, Copenhagen), D. M. Russell (IAC, La Laguna), S. Guziy (Nicolaev, Andalucia), J. Gorosabel (Andalucia, Pais Basco, Bilbao), J. Casares (IAC, La Laguna), M. Armas Padilla (Amsterdam), P. A. Charles (Southampton, Cape Town), R. P. Fender (Southampton), T. M. Belloni (Brera), F. Lewis (FT), S. Motta (ESAC), A. Castro-Tirado (Andalucia), C. G. Mundell (Liverpool JMU), R. Sánchez-Ramírez, C. C. Thöne (Andalucia)

We present a 30-day monitoring campaign of the optical counterpart of the bright X-ray transient Swift J1745-26, starting only 19 minutes after the discovery of the source. We observe the system peaking at i’ ~17.6 on day 6 (MJD 56192) to then decay at a rate of ~0.04 mag/day. We show that the optical peak occurs at least 3 days later than the hard X-ray (15-50 keV) flux peak. Our measurements result in an outburst amplitude greater than 4.3 magnitudes, which favours an orbital period < 21 h and a companion star with a spectral type later than ~ A0. Spectroscopic observations taken with the GTC-10.4 m telescope reveal a broad (FWHM ~ 1100 km/s), double-peaked H alpha emission line from which we constrain the radial velocity semi-amplitude of the donor to be K₂ > 250 km/s. The breadth of the line and the observed optical and X-ray fluxes suggest that Swift J1745-26 is a new black hole candidate located closer than ~7 kpc.

Paper here

A 420 day X-ray/optical modulation and extended X-ray dips in the short-period transient Swift J1753.5-0127

Shaw, A.W. (Southampton), Charles, P.A. (Southampton, Cape Town), Bird, A.J. (Southampton), Cornelisse, R., Casares, J. (IAC, La Laguna), Lewis, F. (FT), Muñoz-Darias, T. (Southampton), Russell, D.M., Zurita, C. (IAC, La Laguna)

We have discovered a 420d modulation, with associated X-ray dips, in RXTE-ASM/MAXI/Swift-BAT archival light-curves of the short-period (3.2h) black-hole X-ray transient, Swift J1753.5-0127. This modulation only appeared at the end of a gradual rebrightening, approximately 3 years after the initial X-ray outburst in mid-2005. The same periodicity is present in both the 2-20 keV and 15-50 keV bands, but with a 0.1 phase offset 40d). Contemporaneous photometry in the optical and near-IR reveals a weaker modulation, but consistent with the X-ray period. There are two substantial X-ray dips (very strong in the 15-50 keV band, weaker at lower energies) that are separated by an interval equal to the X-ray period. This likely indicates two physically separated emitting regions for the hard X-ray and lower energy emission. We interpret this periodicity as a property of the accretion disc, most likely a long-term precession, where the disc edge structure and X-ray irradiation is responsible for the hard X-ray dips and modulation, although we discuss other possible explanations, including Lense-Thirring precession in the inner disc region and spectral state variations. Such precession indicates a very high mass ratio LMXB, which even for a 10 solar mass BH requires a brown dwarf donor (~0.02 solar masses), making Swift J1753.5-0127 a possible analogue of millisecond X-ray pulsars.We compare the properties of Swift J1753.5-0127 with other recently discovered short-period transients, which are now forming a separate population of high latitude BH transients located in the galactic halo.

Paper here

Quiescent X-Ray/Optical Counterparts of the Black Hole Transient H 1705-250

Yi-Jung Yang (Amsterdam), Albert K. H. Kong (Taiwan), David M. Russell (IAC), Fraser Lewis (FT), Rudy Wijnands (Amsterdam)

We report the result of a new Chandra observation of the black hole X-ray transient H 1705-250 in quiescence. H 1705-250 was barely detected in the new 50 ks Chandra observation. With 5 detected counts, we estimate the source quiescent luminosity to be Lx~9.1 x 10³⁰ erg/s in the 0.5-10 keV band (adopting a distance of 8.6 kpc). This value is in line with the quiescent luminosities
found among other black hole X-ray binaries with similar orbital periods. By using images taken with the Faulkes Telescope North, we derive a refined position of H 1705-250. We also present the long-term lightcurve of the optical counterpart from 2006 to 2012, and show evidence for variability in quiescence.

Paper here

Photometry and imaging of comet 103P/Hartley in the 2010-2011 apparition

Giannantonio Milani, Erik Bryssinck, Martino Nicolini, Herman Mikuž, Giovanni Sostero, Paolo Bacci, Walter Borghini, Dario Castellano, Mauro Facchini, Giancarlo Favero, Gianni Galli, Ernesto Guido, Bernhard Hausler, Kamil Hornoch, Nick Howes, Rolando Ligustri, Carmen Perrella, Enrico Prosperi, Jure Skvarč, Jiří Srba, Roberto Trabatti, Carlo Vinante, Gyula Szabó

The results of a CARA (Cometary Archive for Afρ) campaign on comet 103P/Hartley 2 are presented. The main goal was to monitor extensively the comet during the apparition with CCD R and I imaging and photometry, as a support of Epoxi Mission.

Paper here

Overview of an Extensive Multi-wavelength Study of GX 339-4 during the 2010 Outburst

1. Cadolle Bel (ESAC Madrid), J. Rodriguez (Universite Paris Diderot), P. D’Avanzo (Brera, Italy), D. M. Russell (Amsterdam), J. Tomsick (UC Berkeley), S. Corbel (Universite Paris Diderot), F. Lewis (FT), F. Rahoui (Harvard), M. Buxton (Yale), P. Goldoni (Universite Paris Diderot), E. Kuulkers (ESAC Madrid)

The microquasar GX 339-4 experienced a new outburst in 2010: it was observed simultaneously at various wavelengths from radio up to soft gamma-rays. We focused on observations that are quasi-simultaneous with those made with the INTEGRAL and RXTE satellites: these were collected in 2010 March-April during our INTEGRAL Target of Opportunity program, and during some of the other INTEGRAL observing programs with GX 339-4 in the field-of-view. X-ray transients are extreme systems that often harbour a black hole, and are known to emit throughout the whole electromagnetic spectrum when in outburst. The goals of our program are to understand the evolution of the physical processes close to the black hole and to study the connections between the accretion and ejection. We analysed radio, NIR, optical, UV, X-ray and soft gamma-ray observations. We studied the source evolution in detail by producing light curves, hardness-intensity diagrams and spectra. We fitted the broadband data with phenomenological, then physical, models to study the emission coming from the distinct components. Based on the energy spectra, the source evolved from the canonical hard state to the canonical soft state. The source showed X-ray spectral variations that were correlated with changes in radio, NIR and optical emission. The bolometric flux increased from 0.8 to 2.9 x 10⁸ erg / cm² / s while the relative flux and contribution of the hot medium globally decreased. Reprocessing in the disc was likely to be strong at the end of our observations. The source showed a behaviour similar to that of previous outbursts, with some small deviations in the hard X-rays parameters’ evolution. The radio, NIR and optical emission from jets was detected, and seen to fade as the source softened. The results are discussed within the context of disc and jet models.

Paper here

A variable mid-infrared synchrotron break associated with the compact jet in GX 339-4

1. Gandhi (JAXA, Japan), A.W. Blain (Leicester), D.M. Russell (Amsterdam), P. Casella (Southampton), J. Malzac (Toulouse), S. Corbel (Universite Paris Diderot), P. D’Avanzo (Brera, Italy), F.W. Lewis (FT), S. Markoff (Amsterdam), M. Cadolle Bel (ESAC Madrid), P. Goldoni (CEA Saclay), S. Wachter (Caltech), D. Khangulyan (JAXA, Japan), A. Mainzer (JPL)

Many X-ray binaries remain undetected in the mid-infrared, a regime where emission from their compact jets is likely to dominate. Here, we report the detection of the black hole binary GX 339-4 with the Wide-field Infrared Survey Explorer (WISE) during a very bright, hard accretion state in 2010. Combined with a rich contemporaneous multiwavelength dataset, clear spectral curvature is found in the infrared, associated with the peak flux density expected from the compact jet. An optically-thin slope of ~-0.7 and a jet radiative power of > 6 x 10³⁵ erg/s (d/8 kpc)² are measured. A ~24 h WISE light curve shows dramatic variations in mid-infrared spectral slope on timescales at least as short as the satellite orbital period ~95 mins. There is also significant change during one pair of observations spaced by only 11 s. These variations imply that the spectral break associated with the transition from self-absorbed to optically-thin jet synchrotron radiation must be varying across the full wavelength range of ~3-22 microns that WISE is sensitive to, and more. Based on four-band simultaneous mid-infrared detections, the break lies at ~5 x10¹³ Hz in at least two epochs of observation, consistent with a magnetic field B~1.5 x 10⁴ G assuming a single-zone synchrotron emission region. The observed variability implies that either B, or the size of the acceleration zone above the jet base, are being modulated by factors of ~10 on relatively-short timescales.

Paper here

A late jet rebrightening revealed from multi-wavelength monitoring of the black hole candidate XTE J1752-223

D.M. Russell (Amsterdam), P.A. Curran (CEA Saclay), T. Muñoz-Darias (Brera, Italy), F. Lewis (FT), S. Motta, H. Stiele, T. Belloni (Brera, Italy), J.C.A. Miller-Jones (Curtin University, Australia), P.G. Jonker (SRON, Harvard, Nijmegen), K. O’Brien (UC Santa Barbara), J. Homan (MIT), P. Casella (Southampton), P. Gandhi (JAXA, Japan), P. Soleri (Groningen), S. Markoff (Amsterdam), D. Maitra, E. Gallo (Michigan), M. Cadolle Bel (ESAC, Madrid)

We present optical monitoring of the black hole candidate XTE J1752-223 during its 2009 – 2010 outburst and decay to quiescence. The optical light curve can be described by an exponential decay followed by a plateau, then a more rapid fade towards quiescence. The plateau appears to be due to an extra component of optical emission that brightens and then fades over ~ 40 days. We show evidence for the origin of this optical ‘flare’ to be the synchrotron jet during the decaying hard state, and we identify and isolate both disc and jet components in the spectral energy distributions. The optical flare has the same morphology and amplitude as a contemporaneous X-ray rebrightening. This suggests a common origin, but no firm conclusions can be made favouring or disfavouring the jet producing the X-ray flare. The quiescent optical magnitudes are B > 20.6, V > 21.1, R > 19.5, i’ > 19.2. From the optical outburst amplitude we estimate a likely orbital period of < 22 h. We also present near-infrared (NIR) photometry and polarimetry and rare mid-infrared imaging (8 – 12 microns) when the source is nearing quiescence. The fading jet component, and possibly the companion star may contribute to the NIR flux. We derive deep mid-IR flux upper limits and NIR linear polarization upper limits. With the inclusion of radio data, we measure an almost flat jet spectral index between radio and optical; F_nu ~ nu^(~0.05). The data favour the jet break to optically thin emission to reside in the infrared, but may shift to frequencies as high as the optical or UV during the peak of the flare.

Paper here

Testing the jet quenching paradigm with an ultradeep observation of a steadily soft state black hole

1. M. Russell (Amsterdam), J. C. A. Miller-Jones (ICRAR – Curtin), T. J. Maccarone, Y. J. Yang, R. P. Fender (Southampton), F. Lewis (Faulkes Telescope Project, Univ. of Glamorgan, Open University)
   

We present ultradeep radio observations with the Expanded Very Large Array of 4U 1957+11, a Galactic black hole candidate X-ray binary known to exist in a persistent soft X-ray state. We derive a stringent upper limit of 11.4 micro-Jy / beam (3 sigma) at 5-7 GHz, which provides the most rigorous upper limit to date on the presence of jets in a soft state black hole X-ray binary. X-ray, UV and optical fluxes obtained within a few weeks of the radio data can be explained by thermal emission from the disk. At this X-ray luminosity, a hard state black hole X-ray binary that follows the established empirical radio–X-ray correlation would be at least 330-810 times brighter at radio frequencies, depending on the distance to 4U 1957+11. This jet quenching of > 2.5 orders of magnitude is greater than some models predict, and implies the jets are prevented from being launched altogether in the soft state. 4U 1957+11 is also more than one order of magnitude fainter than the faintest of the ‘radio-quiet’ population of hard state black holes. In addition, we show that on average, soft state stellar-mass BHs probably have fainter jets than most active galactic nuclei in a state equivalent to the soft state. These results have implications for the conditions required for powerful, relativistic jets to form, and provide a new empirical constraint for time- and accretion mode-dependent jet models, furthering our understanding of jet production and accretion onto BHs.

Rapid variations of polarization in low-mass X-ray binaries

D.M. Russell (Amsterdam), P.G. Casella, R.P. Fender (Southampton), P. Soleri (Groningen), M.L. Pretorius (ESO, Santiago), F. Lewis (FT), M. van der Klis (Amsterdam)

Time-resolved optical and infrared polarimetric observations of black hole and neutron star lowmass X-ray binaries are presented. Data were acquired with the VLT, UKIRT and HIPPO on the AAO 1.9-m. We find that for some sources in outburst, a rapidly variable component of polarization is evident that is stronger in the redder wavebands. We attribute this to the polarimetric signature of synchrotron emission from jets in these systems, the emission of which is known to dominate these redder bands. Such synchrotron emission from jets launched close to black holes and neutron stars can be highly linearly polarized, depending on the configuration of the magnetic field. The variability of the polarization is suggestive of a tangled and turbulent magnetic field at the location of the compact jet. For some sources the position angle of polarization is consistent with a magnetic field that is parallel to the observed radio jet. These are some of the first observational constraints of the geometry and magnetic structure at the inner regions of the outflow. We also present the first ever simultaneous optical polarization and X-ray campaign of an X-ray binary, using data taken simultaneously with HIPPO and RXTE with sub-second time resolution.

Paper here

A dwarf nova in the globular cluster M13

1. Servillat (Harvard), N.A. Webb (Toulouse), F. Lewis (FT), C. Knigge (Southampton), M. van den Berg (Utrecht/Harvard), A. Dieball (Southampton) and J. Grindlay (Harvard)

Dwarf novae in globular clusters seem to be rare with only 12 detections in the 157 known Galactic globular clusters. We report the identification of a new dwarf nova in M13, the 13th dwarf nova identified in a globular cluster to date. Using the 2m Faulkes Telescope North, we conducted a search for stars in M13 that show variability over a year (2005–2006) on timescales of days and months. This led to the detection of one dwarf nova showing several outbursts. A Chandra X-ray source is coincident with this dwarf nova and shows both a spectrum and variability consistent with that expected from a dwarf nova, thus supporting the identification. We searched for a counterpart in Hubble Space Telescope ACS/WFC archived images and found at least 11 candidates, of which we could characterize only the 7 brightest, including one with a 3 sigma H-alpha excess and a faint blue star. The detection of one dwarf nova when more could have been expected likely indicates that our knowledge of the global Galactic population of cataclysmic variables is too limited. The proportion of dwarf novae may be lower than found in catalogs, or they may have a much smaller duty cycle in general as proposed by some population synthesis models and recent observations in the field.

Paper here

The VLT-FLAMES Tarantula Survey II: R139 revealed as a massive binary system

1. D. Taylor, C. J. Evans, H. Sana, N. R. Walborn, S. E. de Mink, V. E. Stroud, A. Alvarez-Candal, R. H. Barb, J. M. Bestenlehner, A. Z. Bonanos, I. Brott, P. A. Crowther A. de Koter, K. Friedrich, G. Grafener, V. H´enault-Brunet, A. Herrero, L. Kaper, N. Langer, D. J. Lennon, J. Maız Apellaniz, N. Markova, N. Morrell, L. Monaco, and J. S. Vink

We report the discovery that R139 in 30 Doradus is a massive spectroscopic binary system. Multi-epoch optical spectroscopy of R139 was obtained as part of the VLT-FLAMES Tarantula Survey, revealing a double-lined system. The two components are of similar spectral types; the primary exhibits strong C III 4650 emission and is classified as an O6.5 Iafc supergiant, while the secondary is an O6 Iaf supergiant. The radial-velocity variations indicate a highly eccentric orbit with a period of 153.9 days. Photometry obtained with the Faulkes Telescope South shows no evidence for significant variability within an 18 month period. The orbital solution yields lower mass limits for the components of M1 sin³ i = 78 +/- 8 M and M2 sin³ i = 66 +/-7 M. As R139 appears to be the most massive binary system known to contain two evolved Of supergiants, it will provide an excellent test for atmospheric and evolutionary models.

paper here

Isolating the jet in broadband spectra of XBs

1. M. Russell (Amsterdam), F. Lewis (FT), D. Maitra (Michigan), R.J.H. Dunn (Munich), S. Markoff (Amsterdam), P.G. Jonker (SRON, Harvard, Nijmegen), M. Linares (MIT), V. Tudose (Netherlands Institute for Radio Astronomy)

Most accretion-powered relativistic jet sources in our Galaxy are transient X-ray binaries (XBs). Efforts to coordinate multiwavelength observations of these objects have improved dramatically over the last decade. Now the challenge is to interpret broadband spectral energy distributions (SEDs) of XBs that are well sampled in both wavelength and time. Here we focus on the evolution of the jet in their broadband spectra. Some of the most densely sampled broadband SEDs of a neutron star transient (IGR J00291+5934) are used to constrain the optically thick–thin break in the jet spectrum. For the black hole transient XTE J1550-564, infrared – X-ray correlations, evolution of broadband spectra and timing signatures indicate that synchrotron emission from the jet likely dominates the X-ray power law at low luminosities  during the hard state outburst decline.

Paper here

Observational detection of eclipses of J5 Amalthea by the Galilean satellites

A.A. Christou (Armagh), F. Lewis, P. Roche (FT), M.G. Hidas, T.M. Brown (LCOGT, Santa Barbara)

Aims. We carried out observations of the small jovian satellite Amalthea (J5) as it was being eclipsed by the Galilean satellites near the 2009 equinox of Jupiter in order to apply the technique of mutual event photometry to the astrometric determination of this satellite’s position.

Methods. The observations were carried out during the period 06/2009−09/2009 from the island of Maui, Hawaii and Siding Spring, Australia with the 2m Faulkes Telescopes North and South respectively. We observed in the near-infrared part of the spectrum using a PanStarrs-Z filter with Jupiter near the edge of the field in order to mitigate against the glare from the planet. Frames were acquired at rates > 1/min during eclipse times predicted using recent JPL ephemerides for the satellites. Following subtraction of the sky background from these frames, differential aperture photometry was carried out on Amalthea and a nearby field star.

Results. We have obtained three lightcurves which show a clear drop in the flux from Amalthea, indicating that an eclipse took place as predicted. These were model-fitted to yield best estimates of the time of maximum flux drop and the impact parameter. These are consistent with Amalthea’s ephemeris but indicate that Amalthea is slightly ahead of, and closer to Jupiter than, its predicted position by approximately half the ephemeris uncertainty in these directions. We argue that a ground-based campaign of higher-cadence photometry accurate at the 5% level or better during the next season of eclipses in 2014-15 should yield positions to within 0.̣05″ and affect a corresponding improvement in Amalthea’s ephemeris.

Paper here

Quiescent limits of GRO J1655-40 & XTE J1550-564

by D. E. Calvelo (Southampton), R. P. Fender (Southampton), D. M. Russell (Amsterdam), E. Gallo (UC Santa Barbara, MIT), S. Corbel (Paris), A. K. Tzioumis (Australia Telescope National Facility), M. E. Bell (Southampton), F. Lewis (FT), T. J. Maccarone(Southampton)

We present the results of radio observations of the black hole binaries GRO J1655-40 and XTE J1550-564 in quiescence, with the upgraded Australia Telescope Compact Array. Neither system was detected. Radio flux density upper limits (3 sigma) of 26 micro Jy (at 5.5 GHz), 47 micro Jy (at 9 GHz) for GRO J1655-40, and 1.4 mJy (at 1.75 GHz), 27 micro Jy (at 5.5 GHz), 47 micro Jy (at 9 GHz) for XTE J1550-564 were measured. In conjunction with quasi-simultaneous Chandra X-ray observations (in the case of GRO J1655-40) and Faulkes Telescope optical observations (XTE J1550-564) we find that these systems provide the first evidence of relatively `radio quiet’ black hole binaries at low luminosities; indicating that the scatter observed in the hard state X-ray:radio correlation at higher luminosities may also extend towards quiescent levels.

preprint here

The Double-Peaked 2008 Outburst of the Accreting Milli-Second X-ray Pulsar, IGR J00291+5934

by F.Lewis (FT), D.M.Russell (Amsterdam), P.G.Jonker (SRON, Harvard, Nijmegen), M.Linares (Amsterdam, MIT), V.Tudose(Netherlands Institute for Radio Astronomy), P.Roche (FT), J.S.Clark (Open), M.A.P.Torres (Harvard), D.Maitra (Amsterdam, Michigan), C.G.Bassa (Jodrell Bank), D.Steeghs (Harvard, Warwick), A.Patruno (Amsterdam), S.Migliari (ESAC), R.Wijnands(Amsterdam), G.Nelemans (Nijmegen), L.J.Kewley (Hawaii), V.E.Stroud (FT), M.Modjaz (Hawaii, Berkeley), J.S.Bloom (Berkeley), C.H.Blake (Harvard), D.Starr (Berkeley, LCOGT)

In August 2008, the accreting milli-second X-ray pulsar (AMXP), IGR J00291+5934, underwent an outburst lasting ~ 100 days, the first since its discovery in 2004. We present data from the double-peaked outburst from Faulkes Telescope North, the INT, the Keck Telescope, PAIRITEL, the Westerbork Synthesis Radio Telescope and the Swift, XMM-Newton and RXTE X-ray missions. We study the outburst’s evolution at various wavelengths. We study the light curve morphology, presenting the first radio-X-ray Spectral Energy Distributions (SEDs) for this source and the most detailed UV-IR SEDs for any outbursting AMXP. We show simple models that attempt to identify the emission mechanisms responsible. We analyse short-timescale optical variability, and compare a medium resolution optical spectrum with those from 2004. The outburst morphology is unusual for an AMXP, comprising two peaks, the second containing a ‘plateau’ of ~ 10 days at maximum brightness within 30 days of the initial activity. This has implications on duty cycles of short-period X-ray transients. The X-ray spectrum can be fitted by a single, hard power-law. We detect optical variability of ~ 0.05 magnitudes, on timescales of minutes, but find no periodic modulation. In the optical, the SEDs contain a blue component, indicative of an irradiated disc, and a transient near-infrared (NIR) excess. This excess is consistent with a simple model of an optically thick synchrotron jet (as seen in other outbursting AMXPs). The optical spectrum shows a double-peaked H alpha profile, a diagnostic of an accretion disc, but we do not clearly see other lines (e.g. He I, II) reported in 2004. Optical/IR observations of AMXPs are excellent for studying the evolution of both the outer accretion disc and the inner jet, and may eventually provide us with tight constraints to model disc-jet coupling in accreting neutron stars.

preprint here

A Long-term optical X-ray correlation in 4U 1957+11

by D.M. Russell (Amsterdam), F. Lewis, P. Roche (FT), J.S. Clark (Open University), E. Breedt, R.P. Fender (Southampton)

We present three years of optical monitoring with the Faulkes Telescopes of the Low-Mass X-ray Binary, 4U 1957+11. We see long-term variations which are correlated with X-ray flux as measured by the RXTE satellite’s ASM instrument.

preprint here

The VLT-FLAMES Tarantula Survey

by Chris Evans (UK ATC, Royal Observatory, Edinburgh) et al.

The Tarantula Survey is an ambitious ESO Large Programme that has obtained multi-epoch spectroscopy of over 1,000 massive stars in the 30 Doradus region of the Large Magellanic Cloud. Here we introduce the scienti c motivations of the survey and give an overview of the observational sample. Ultimately, quantitative analysis of every star, paying particular attention to the effects of rotational mixing and binarity, will be used to address fundamental questions in both stellar and cluster evolution.

preprint here

CCD BV Photometry of three southern galactic open clusters using Faulkes Telescope South

A paper to be published in the August issue of the British Astronomical Association (BAA) Journal by David Boyd along with staff and students of Kennet School, Thatcham.

Boyd paper

Jupiter – IAU Circular 9055

23. A. Christou, Armagh Observatory, reports that his CCD photometry of Jupiter V (Amalthea), obtained by F. Lewis (Faulkes Telescope Project, Open University) using the 2-m Faulkes Telescope South (+ Pan-STARRS z’ filter) reveals an eclipse of this satellite by Jupiter I (Io) on June 23 UT. Twenty-five 5-sec exposures were acquired between June 23.64799 and 23.66425. Amalthea was visible in all these frames with the exception of those starting at June 23.65317 and 23.65379 UT, consistent with a totality between June 23.65292 and 23.65401 predicted by utilizing a generic mutual- eclipse model (Christou 2005, Icarus 178, 171) in combination with the SPICE ephemeris kernel JUP230 for the Galilean satellites and Amalthea. Observations at high cadence (<< 60 s) of further eclipses of Amalthea by Io are encouraged during the current Jovian equinox season. Predictions for July and August 2009 are givenhere

Robotic Astronomy with the Faulkes Telescopes and Las Cumbres Observatory Global Telescope

by F. Lewis (FT), R. Street (LCOGT), P. Roche, V. Stroud (FT), D.M. Russell (Amsterdam)

submitted to the ‘Robotic Astronomy’ issue of ‘Advances in Astronomy’

We present results from ongoing science projects conducted by members of the Faulkes Telescope (FT) team and Las Cumbres Observatory Global Telescope (LCOGT). Many of these projects incorporate observations carried out and analysed by FT users, comprising amateur astronomers and schools. We also discuss plans for the further development of the LCOGT network.

Malaga proceedings

The Faulkes Telescope Project: Not Just Pretty Pictures

by F. Lewis (FT), P. Roche (FT)

published in “.Astronomy: Networked Astronomy and the New Media”, 2009, edited by R.J. Simpson, D. Ward-Thompson

The Faulkes Telescope (FT) Project is an educational and research arm of the Las Cumbres Observatory Global Telescope Network (LCOGTN). As well as producing spectacular images of galaxies, nebulae, supernovae remnants, star clusters, etc., the FT team is involved in several projects pursuing scientific goals. Many of these projects also incorporate data collected and analysed by schools and amateur astronomers.

Available here

Astrometric observations of the Uranian satellites with the Faulkes Telescope North in 2007 September

by M.Y. Khovritchev (Central Astronomical Observatory of Russian Academy of Science)

published in MNRAS, 2009, 393, 1353-1358

Available here

Observational detection of eight mutual eclipses and occultations between the satellites of Uranus

by A. A. Christou (Armagh Observatory), F. Lewis (FT), P. Roche(FT), Y. Hashimoto (SAAO, SALT), D. O’Donoghue (SAAO), H. Worters (SAAO, SALT), D. A. H. Buckley (SAAO, SALT), T. Michalowski (Poznan), D. J. Asher (Armagh), A. Bitsaki (Athens), A. Psalidas (Patras), V. Tsamis (Athens), K. N. Gourgouliatos (Cambridge), A. Liakos (Athens), M. G. Hidas (LCOGT), T. M. Brown (LCOGT)

Published in Astronomy and Astrophysics (A&A)

Available here

Social Networking: An astronomer’s field guide

by Gomez, E.L., Gomez H.L., Yardley, J.

published in “.astronomy: Networked Astronomy and the New Media”, 2009, edited by R.J. Simpson, D. Ward-Thompson

We present a brief introduction to the phenomenon of “social networking” and its potentially powerful use as an astronomy outreach and educational tool. We briefly discuss the development of applications for websites and Facebook, and the use of web trackers such as Google Analytics to analyze the audience. Finally we discuss how social bookmarking can be used to promote work to unexpected audiences.

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Optical spectroscopy and photometry of SAX J1808.4-3658 in outburst

by P. Elebert (Cork), M. T. Reynolds (Michigan), P. J. Callanan (Cork), D. J. Hurley (Cork), G. Ramsay (Armagh), F. Lewis (FT), D. M. Russell (Amsterdam), B. Nord (Michigan), S. R. Kane (Caltech), D. L. DePoy (Texas A&M), P. Hakala (Turku)

published in MNRAS

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An observation of a mutual event between two satellites of Uranus

by M.G. Hidas (LCOGT), A.A. Christou (Armagh), T.M. Brown (LCOGT)

published in MNRAS, 2008, 384, L38-L40

We present observations of the occultation of Umbriel by Oberon on 2007 May 4. We believe this is the first observed mutual event between satellites of Uranus. Fitting a simple geometric model to the light curve, we measure the mid-event time with a precision of 4 s. We assume previously measured values for the albedos of the two satellites, and measure the impact parameter to be 500 +/- 80 km. These measurements are more precise than estimates based on current ephemerides for these satellites. Therefore observations of additional mutual events during the 2007-2008 Uranian equinox will provide improved estimates of their orbital and physical parameters.

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Unifying disc-jet behaviour in X-ray binaries: an optical/IR approach

by D.M. Russell (Amsterdam), D. Maitra (Amsterdam), R.P. Fender (Southampton), F. Lewis (FT)

published in Proceedings of the 7th Microquasar Workshop: Microquasars and Beyond, September 2008, Foca, Turkey

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Continued Monitoring of LMXBs with the Faulkes Telescopes

by F. Lewis (FT) D.M. Russell (Amsterdam), R.P. Fender (Southampton), Paul Roche (FT), J.S. Clark (Open University)

published in Proceedings of the 7th Microquasar Workshop: Microquasars and Beyond, September 2008, Foca, Turkey

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The nature of the close magnetic white dwarf + probable brown dwarf binary SDSS J121209.31+013627.7

by M.R. Burleigh (Leicester), T.R. Marsh (Warwick), B.T. Gänsicke (Warwick), M.R. Goad (Leicester), V.S. Dhillon (Sheffield), S.P. Littlefair (Sheffield), M.Wells (Oundle School), N.P. Bannister, C.P. Hurkett, A. Martindale, P.D. Dobbie, S.L. Casewell, D.E.A. Baker, J. Duke (Leicester), J. Farihi (Gemini Observatory), M.J. Irwin (Cambridge), P.C. Hewett (Cambridge), P. Roche (FT), F. Lewis (FT)

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