scholarly journals GLORIA and Study of Cataclysmic Variables

2015 ◽  
Vol 2 (1) ◽  
pp. 303-307
Author(s):  
R. Hudec ◽  
V. Šimon
Keyword(s):  
Open Access ◽  
Access Network ◽  
Cataclysmic Variables ◽  
X Ray ◽  
The World ◽  
Robotic Telescopes ◽  
Intermediate Polars

We report here on the ongoing EU FP7 Project GLORIA (GLObal Robotic-telescopes Intelligent Array) with emphasis on possibility of investigation of cataclysmic variables by users. GLORIA will enable the first free and open-access network of robotic telescopes in the world. We show several examples of the not often used topics (but suitable for GLORIA) for the studies of activity of cataclysmic variables, e.g. search for outbursts in intermediate polars and the fluctuations of brightness in their quiescence, and investigation of the optical counterparts of supersoft X-ray sources.

scholarly journals “PI OF THE SKY” OFF-LINE EXPERIMENT WITH GLORIA

2014 ◽  
Vol 54 (3) ◽  
pp. 205-209
Author(s):  
Ariel Majcher ◽  
Arkadiusz Cwiek ◽  
Mikołaj Cwiok ◽  
Lech Mankiewicz ◽  
Marcin Zaremba ◽  
...  
Keyword(s):  
Open Access ◽  
Web 2.0 ◽  
Access Network ◽  
Free Access ◽  
Astronomical Data ◽  
Research Level ◽  
The World ◽  
Robotic Telescopes ◽  
Robotic Telescope ◽  
The Web

GLORIA is the first free and open-access network of robotic telescopes in the world. Based on the Web 2.0 environment, amateur and professional users can do research in astronomy by observing with robotic telescope, and/or analyzing data acquired with GLORIA, or from other free access databases. The GLORIA project develops free standards, protocols and tools for controlling Robotic Telescopes and related instrumentation, for scheduling observations in the telescope network, and for conducting so-called off-line experiments based on the analysis of astronomical data. This contribution summarizes the implementation and results from the first research level off-line demonstrator experiment implemented in GLORIA, which was based on data collected with the “Pi of the Sky” telescope in Chile.

scholarly journals A Fuse Survey of Disk-Accreting Cataclysmic Variables

2004 ◽  
Vol 194 ◽  
pp. 251-251
Author(s):  
C. S. Froning ◽  
K. S. Long ◽  
P. Szkody ◽  
B. T. Gänsicke
Keyword(s):  
Cataclysmic Variables ◽  
Dwarf Novae ◽  
X Ray ◽  
Intermediate Polars ◽  
Far Ultraviolet ◽  
X Ray Binaries ◽  
Initial Results

We present initial results of a survey of the FUV spectra of disk-accreting cataclysmic variables obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE).FUSE covers the 905 - 1188 Å range at spectral resolutions ≃0.1 Å. To date, FUSE has observed more than 65 cataclysmic variables (CVs). Publicly-available data include observations of 11 dwarf novae (DN), 15 non-magnetic novalikes (NLs), 7 intermediate polars and DQ Her stars, at least 15 polars, and 4 super-soft X-ray binaries.

scholarly journals X-Ray Observations of Cataclysmic Variables

1987 ◽  
Vol 93 ◽  
pp. 207-223
Author(s):  
J.P. Osborne
Keyword(s):  
Light Curve ◽  
Spectral Range ◽  
Cataclysmic Variables ◽  
High Sensitivity ◽  
Light Curves ◽  
X Ray ◽  
Broad Spectral Range ◽  
Intermediate Polars ◽  
Recurrent Nova

AbstractThe X-ray observatory EXOSAT spent over 1000 hours observing cataclysmic variables. Some of the major results reviewed here are: soft X-ray light curve changes in AM Her objects, orbital effects in the X-ray light curves of intermediate polars and U Gem, regular behaviour in the inter-outburst X-ray flux of VW Hyi, and X-ray emission from the tenuous remnant of the recent recurrent nova RS Oph. The ability of EXOSAT to make long uninterupted observations at high sensitivity over a broad spectral range and to react quickly to cosmic events has yielded a dataset of a quality that will not be surpassed for many years.

scholarly journals Mass Accretion in Intermediate Polar V1223 Sgr

2012 ◽  
Vol 8 (S290) ◽  
pp. 225-226
Author(s):  
Ladislav Hric ◽  
Emil Kundra ◽  
Rudolf Gális
Keyword(s):  
Accretion Rate ◽  
Spectral Band ◽  
Cataclysmic Variables ◽  
X Ray ◽  
Mass Accretion Rate ◽  
Intermediate Polars ◽  
Activity State

AbstractIntermediate polars (IPs) represent more than 70% of all cataclysmic variables (CVs) detected by INTEGRAL in hard X-ray. Nevertheless, only a quarter of all known IPs have been detected in this spectral band. This fact can be related to the activity state of these object ruled by changes in the mass accretion rate.

scholarly journals New transient Galactic bulge intermediate polar candidate XMMU J175035.2-293557

2018 ◽  
Vol 615 ◽  
pp. L7 ◽  
Author(s):  
F. Hofmann ◽  
G. Ponti ◽  
F. Haberl ◽  
M. Clavel
Keyword(s):  
Galactic Center ◽  
Cataclysmic Variables ◽  
Galactic Bulge ◽  
Optical Counterpart ◽  
X Ray ◽  
The Past ◽  
System A ◽  
Variable Factor ◽  
Intermediate Polars ◽  
X Ray Absorption

Context. For the past decades, a rare subclass of cataclysmic variables (CV), with magnetised white dwarfs (WD) as accretors, has been studied. They are called intermediate polars (IP) and have been suggested to be the main contributors to the diffuse, hard X-ray emission close to the Galactic center (GC) and in the Galactic bulge (GB), because most of them are unresolved there. Aims. In an ongoing X-ray survey (0.5–10 keV energy band) of 3° × 3° around the GC with the XMM-Newton observatory, we conducted a systematic search for transient X-ray sources. Methods. Promising systems were analyzed for spectral, timing, and multiwavelength properties to constrain their nature. Results. We discovered a new highly variable (factor ≳20) X-ray source about 1.25° south of the GC. We found evidence that makes the newly discovered system a candidate IP. The X-ray light curve shows a period of 511 ± 10 s, which can be interpreted as the spin period of the WD. The X-ray spectrum is well fit by a bremsstrahlung model with a temperature of 13.9 ± 2.5 keV, suggesting a WD mass of 0.4−0.5 M⊙. We were unable to identify a blue optical counterpart in any of the candidate sources, as would be expected for IPs. Conclusions. The high X-ray absorption and absence of a clear optical counterpart suggest that the source is most likely located in the GB. This would make the system a transient IP (GK Per class) with an especially high peak X-ray luminosity, which means that it is a very faint X-ray transient.

scholarly journals Monitoring of X-Ray Sources in the Optical Spectral Region

2010 ◽  
Vol 2010 ◽  
pp. 1-12
Author(s):  
Vojtěch Šimon
Keyword(s):  
Gamma Ray ◽  
Cataclysmic Variables ◽  
Physical Processes ◽  
X Ray ◽  
Low Mass ◽  
Intermediate Polars ◽  
Photometric Monitoring ◽  
The Individual ◽  
X Ray Binaries ◽  
Review Current

We review current results and perspectives of the photometric monitoring of the optical counterparts of X-ray sources of various kinds (binary X-ray sources (cataclysmic variables and low-mass X-ray binaries, supersoft X-ray sources, microquasars), gamma-ray bursts). We discuss the problems of the monitoring of the individual kinds of objects in the optical and X-ray passbands. We show the importance of multifilter monitoring to obtain a deeper understanding of the physical processes and to resolve between the individual emission mechanisms. We also show that there are brief, unique, and little understood phenomena which are very promising targets for the optical monitoring, for example, flares in intermediate polars.

scholarly journals Energy Distribution of Hard X-Ray Emitting Cataclysmic Variables

1983 ◽  
Vol 72 ◽  
pp. 173-180 ◽  
Author(s):  
Martine Mouchet
Keyword(s):  
Energy Distribution ◽  
Cataclysmic Variables ◽  
X Ray ◽  
Disc Model ◽  
Accretion Rates ◽  
Extreme Uv ◽  
Optical Continuum ◽  
Intermediate Polars ◽  
Standard Disc

ABSTRACTWe present the energy distribution of three hard X-ray sources H2252-035, 4U1849-31 and 2A0526-328 identified with intermediate polars. The ultraviolet and optical continuum can be well described by the standard disc model but this requires rather large discs and high accretion rates. Other possible contributions to the energy distribution are estimated. The predicted high accretion rates as well as the amplitude of the optical pulsations are in disagreement with the observed X-ray luminosity suggesting the existence of an unseen soft X-ray or extreme UV component.

scholarly journals Cataclysmic Variables — X-rays and Optical Activity in V1223 Sgr and V709 Cas

10.14311/1464 ◽  
2011 ◽  
Vol 51 (6) ◽  
Author(s):  
R. Gális ◽  
L. Hric ◽  
E. Kundra ◽  
F. Münz
Keyword(s):  
Optical Activity ◽  
Cataclysmic Variables ◽  
Galactic Centre ◽  
Source Population ◽  
X Rays ◽  
Major Fraction ◽  
X Ray ◽  
Physical Mechanisms ◽  
Intermediate Polars ◽  
Activity State

Intermediate polars are a major fraction of all cataclysmic variables detected by INTEGRAL in hard X-ray. These objects have recently been proposed to be the dominant X-ray source population detected near the Galactic centre, and they also contribute significantly to X-ray diffuse Galactic ridge emission. Nevertheless, only 25% of all known intermediate polars have been detected in hard X-ray. This fact can be related to the activity state of these close interacting binaries.A multi-frequency (from optical to X-ray) investigation of intermediate polars is essential for understanding the physical mechanisms responsible for the observed activity of these objects.

scholarly journals Exploring the space density of X-ray selected cataclysmic variables

2018 ◽  
Vol 619 ◽  
pp. A62 ◽  
Author(s):  
A. D. Schwope
Keyword(s):  
Cataclysmic Variables ◽  
Scale Height ◽  
Space Density ◽  
Sky Surveys ◽  
X Ray ◽  
Long Period ◽  
Upper Limits ◽  
Intermediate Polars ◽  
The Impact ◽  
Larger Sample

The space density of the various classes of cataclysmic variables (CVs) has up to now only been weakly constrained, due to the small number of objects in complete X-ray flux-limited samples and the difficulty in deriving precise distances to CVs. The former limitation still exists. Here the impact of Gaia parallaxes and implied distances on the space density of X-ray-selected complete, flux-limited samples is studied. These samples have been described in the literature: Those of non-magnetic CVs are based on ROSAT (RBS – ROSAT Bright Survey & NEP – North Ecliptic Pole) and that of the intermediate polars (IPs) stems from Swift/BAT. All CVs appear to be rarer than previously thought, although the new values are all within the errors of past studies. Upper limits at 90% confidence for the space densities of non-magnetic CVs are ρRBS < 1.1 × 10−6 pc−3 and ρRBS+NEP < 5.1 × 10−6 pc−3 for an assumed scale height of h = 260 pc and ρIPs < 1.3 × 10−7 pc−3 for the long-period IPs at a scale height of 120 pc. Most of the distances to the IPs have previously been under-estimated. The upper limits to the space densities are only valid in cases where CVs do not have lower X-ray luminosities than the lowest-luminosity member of the sample. These results require confirmation using larger sample sizes, soon to be established through sensitive X-ray all-sky surveys to be performed with eROSITA on the Spektrum-X-Gamma mission.

scholarly journals Suzaku View of Magnetic Cataclysmic Variables

2015 ◽  
Vol 2 (1) ◽  
pp. 99-102
Author(s):  
T. Yuasa
Keyword(s):  
Cataclysmic Variables ◽  
Emission Lines ◽  
Spectral Model ◽  
Cataclysmic Variable ◽  
X Ray ◽  
Intermediate Polars ◽  
Magnetic Cataclysmic Variables

Results of magnetic cataclysmic variable studies performed with the Suzaku satellite are reviewed in this article. Particular emphasis is placed on the recent update of X-ray spectral model of intermediate polars, possible kinematically redshifted fluorescent Fe K emission lines, and the magnetic CV contribution to the Galactic ridge X-ray emission.

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