122 citations · 3.4k across the 145 of their papers we have counts for
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The defining characteristics of Intermediate Polars - the case of three candidate systems
Gavin Ramsay, Peter J. Wheatley, A. J. Norton +2
Intermediate Polars (IPs) are a group of cataclysmic variables (CVs) which are thought to contain white dwarfs which have a magnetic field strength in the range ~0.1-10MG. A signif…
The Coherent Radio Emission from the RS CVn Binary HR 1099
O. B. Slee, W. Wilson, G. Ramsay
We used the Australia Telescope in March-April 2005 to observe the RS CVn binary HR 1099 at 1.384 and 2.368 GHz at two epochs, each of 9 h in duration and 11 days apart. During two…
The X-ray spectrum of RX J1914.4+2456 revisited
Gavin Ramsay
It has been proposed that RX J1914.4+2456 is a stellar binary system with an orbital period of 9.5 mins. As such it shares many similar properties with RX J0806.3+1527 (5.4 mins).…
A search for electron cyclotron maser emission from compact binaries
Gavin Ramsay, Catherine Brocksopp, Kinwah Wu +2
Unipolar induction (UI) is a fundamental physical process, which occurs when a conducting body transverses a magnetic field. It has been suggested that UI is operating in RX J0806+…
A study of Jupiter's aurorae with XMM-Newton
G. Branduardi-Raymont, A. Bhardwaj, R. F. Elsner +6
We present a detailed analysis of Jupiter's X-ray (0.2-10 keV) auroral emissions as observed by XMM-Newton in Nov. 2003 and compare it with that of an Apr. 2003 observation. We dis…
SDSS J0926+3624, the first eclipsing AM CVn star, as seen by ULTRACAM
T. R. Marsh, V. S. Dhillon, S. Littlefair +6
We present light curves of SDSS J0926+3624, the first eclipsing AM CVn star, observed with the high-speed CCD camera ULTRACAM on the WHT. We find unusually that the accreting white…
Recent observational progress in AM CVn binaries
G. Ramsay, C. Brocksopp, P. Groot +9
We present the results of some recent research on AM CVn systems. We present: X-ray/UV observations made using XMM-Newton; the X-ray grating spectrum of RX J1914+24; preliminary re…
Latest results on Jovian disk X-rays from XMM-Newton
G. Branduardi-Raymont, A. Bhardwaj, R. F. Elsner +6
We present the results of a spectral study of the soft X-ray emission (0.2-2.5 keV) from low-latitude (`disk') regions of Jupiter. The data were obtained during two observing campa…
A search for stellar X-ray sourcesin the Sagittarius and Carina dwarf galaxies - I: X-ray observations
G. Ramsay, K. Wu
ROSAT observations found no convincing evidence for X-ray sources located in local dwarf spheroidal galaxies (dSph). Now with more sensitive instruments on board Chandra and XMM-Ne…
Multi-band Astronomy with LISA
G. Branduardi-Raymont, G. Ramsay, C. Wang +2
We discuss astrophysical scenarios relevant to the generation of gravitational waves (GW) and effects expected to arise from the interaction of GW and electromagnetic (EM) radiatio…
XMM-Newton observations of AM CVn binaries: V396 Hya & SDSS J1240-01
Gavin Ramsay, Paul J. Groot, Tom Marsh +3
We present the results of XMM-Newton observations of two AM CVn systems - V396 Hya and SDSS J1240-01. Both systems are detected in X-rays and in the UV: neither shows coherent vari…
RApid Temporal Survey - RATS II: Followup observations of 4 newly discovered short period variables
Gavin Ramsay, Ralf Napiwotzki, Pasi Hakala +1
The RApid Temporal Survey (RATS) is a survey to detect objects whose optical intensity varies on timescales of less than ~70 min. In our pilot dataset taken with the INT and the Wi…
XMM-Newton and Chandra observations of the ultra-compact binary RX J1914+24
Gavin Ramsay, Mark Cropper, Pasi Hakala
The nature of the X-ray source RX J1914+24 has been the subject of much debate. It shows a prominent period of 569 sec in X-rays and the optical/infra-red: in most models this has…
XMM-Newton observations of X-ray emission from Jupiter
G. Branduardi-Raymont, A. Bhardwaj, R. F. Elsner +6
We present the results of two XMM-Newton observations of Jupiter carried out in 2003 for 100 and 250 ks (or 3 and 7 planet rotations) respectively. X-ray images from the EPIC CCD c…
Chandra observations of the globular cluster M54
Gavin Ramsay, Kinwah Wu
We have carried out a Chandra observation of the globular cluster M54. We detected 7 sources located within the half-mass radius of M54, at a flux limit of 1.5x10^-15 erg/s/cm in t…
XMM-Newton observations of AM CVn binaries
Gavin Ramsay, Pasi Hakala, Tom Marsh +3
We present the results of XMM-Newton observations of four AM CVn systems -- AM CVn, CR Boo, HP Lib and GP Com. Their light curves show very different characteristics. The X-ray lig…
Solar Control on Jupiter's Equatorial X-ray Emissions: 26-29 November 2003 XMM-Newton Observation
Anil Bhardwaj, Graziella Branduardi-Raymont, Ronald F. Elsner +6
During November 26-29, 2003 XMM-Newton observed soft (0.2-2 keV) X-ray emission from Jupiter for 69 hours. The low-latitude X-ray disk emission of Jupiter is observed to be almost…
Two-temperature accretion flows in magnetic cataclysmic variables: Structures of post-shock emission regions and X-ray spectroscopy
Curtis Saxton, Kinwah Wu, Mark Cropper +1
We use a two-temperature hydrodynamical formulation to determine the temperature and density structures of the post-shock accretion flows in magnetic cataclysmic variables (mCVs) a…
XMM-Newton EPIC and OM Observations of Her X-1 over the 35 d Beat Period and an Anomalous Low State
S. Zane, G. Ramsay, M. A. Jimenez-Garate +4
We present the results of a series of XMM-Newton EPIC and OM observations of Her X-1, spread over a wide range of the 35 d precession period. We confirm that the spin modulation of…
RApid Temporal Survey - RATS I: Overview and first results
Gavin Ramsay, Pasi Hakala
We present the aim and first results of the RApid Temporal Survey (RATS) made using the Wide Field Camera on the Isaac Newton Telescope. Our initial survey covers 3 square degrees,…
High-speed, energy-resolved, STJ observations of the AM Her system V2301 Oph
A. P. Reynolds, G. Ramsay, J. H. J. de Bruijne +4
We present high time-resolution optical energy-resolved photometry of the eclipsing cataclysmic variable V2301 Oph made using the ESA S-Cam detector, an array of photon counting su…
Geometrical constraints upon the unipolar model of V407 Vul and RXJ0806.3+1527
S. C. C. Barros, T. R. Marsh, P. Groot +5
V407 Vul and RX J0806.3+1527 are X-ray emitting stars with X-ray light curves that are 100% modulated on periods of 569 and 321 seconds respectively. These periods and no others ar…
XMM-Newton observations of the ultra-compact binary RX J1914+24
Gavin Ramsay, Pasi Hakala, Kinwah Wu +4
We present XMM-Newton observations of the 569 sec period system RX J1914+24 (V407 Vul). This period is believed to represent the binary orbital period making it an ultra-compact bi…
XMM-Newton observations of UW CrB -- detection of X-ray bursts and evidence for accretion disc evolution
P. Hakala, G. Ramsay, P. Muhli +4
UW CrB (MS1603+2600) is a peculiar short period X-ray binary that exhibits extraordinary optical behaviour. The optical light curve shape of the system changes drastically from nig…