We present multi-wavelength temporal and spectral characteristics of a magnetic cataclysmic variable (MCV) Swift J0503.7-2819, using far ultraviolet (FUV) and X-ray data from AstroSat, supplemented with optical data from the Southern African Large Telescope and X-ray data from the XMM-Newton and Swift observatories. The X-ray modulations at 4897.6657 s and 3932.0355 s are interpreted as the orbital ($P_{\Omega}$) and spin ($P_{\omega}$) period, respectively, and are consistent with prior reports. With a spin-orbit period ratio of 0.8 and $P_{\Omega}$ falling below the period gap (2-3 hrs) of CVs, Swift J0503.7-2819 would be the newest addition to the growing population of nearly synchronous MCVs, which we call EX Hya-like systems. Hard X-ray luminosity of $<$ $2.5\times10^{32} erg s^{-1}$, as measured with the Swift Burst Alert Telescope, identifies it to be a low-luminosity intermediate polar, similar to other EX Hya-like systems. The phenomenology of the light curves and the spectral characteristics rule out a purely disc-fed/stream-fed model and instead reveal the presence of complex accretion structures around the white dwarf. We propose a ring-like accretion flow, akin to EX Hya, using period ratio, stability arguments, and observational features. An attempt is made to differentiate between the asynchronous polar/nearly-synchronous intermediate polar nature of Swift J0503.7-2819. Further, we note that with the advent of sensitive surveys, a growing population of MCVs that exhibit characteristics of both polars and intermediate polars is beginning to be identified, likely forming a genealogical link between the two conventional classes of MCVs.

We present our AstroSat soft X-ray observations of a compact binary system, AR Sco, and analysis of its X-ray observations with Chandra that were taken only about a week before the AstroSat observations. An analysis of the soft X-ray (0.3–2.0 keV) data limits the modulation of the spin, orbital, or beat periods to less than 0.03 counts s $$^{-1}$$ or <10% of the average count rate. The X-ray flux obtained from both observatories is found to be almost identical (within a few percent) in flux, and about 30% lower than reported from the nine months older observations with XMM-Newton. A two-temperature thermal plasma model with the same spectral parameters fit Chandra and AstroSat data very well, and requires very little absorption in the line of sight to the source. The low-temperature component has the same temperature ( $$\sim $$ 1 keV) as reported earlier, but the high-temperature component has a lower temperature of 5.0 $$^{+0.8}_{-0.7}$$  keV as compared to 8.0 keV measured earlier, however, the difference is not statistically significant.

We summarize the results of a line-by-line fitting analysis of the available spectra obtained using the Chandra High-Energy Transmission Grating. We confirm the existence of broad ionization and electron temperature ranges and high number densities in cataclysmic variables (CVs) of all subtypes. Temperatures range from ∼0.4 keV to ∼5–10 keV or more with a broad range detected in any given CV. In other words, single-temperature models do not describe the line emission. Number densities also cover a broad range, from 1012 to >1016 cm−3. We demonstrate that much of the plasma is in a nonequilibrium state; the Fe emission, however, may arise from plasma in the ionization equilibrium.

: JMAPS is a small, space-based, all-sky visible wavelength astrometric and photometric survey mission for oth through 14th V-band magnitude stars with a 2012 launch. The primary objective of the JMAPS mission is the generation of an astrometric star catalog with better than 1 milliarcsecond positional accuracy and photometry to the 1% accuracy level or better at 1st to 12th mag. A I-mas all-sky survey will have a significant impact on our current understanding of galactic and stellar astrophysics. JMAPS will improve our understanding of the origins of nearby young stars, provide insight into the dynamics of star formation regions and associations, investigate the dynamics and membership of nearby open clusters, and discover the smallest brown dwarfs at distances up to 5 pc after a 2-year mission, and Jupiter-like planets out to 3 pc after 4 years.

Results from a study of Fe Kα emission lines for a sample of six nonmagnetic cataclysmic variables (CVs) using high-resolution X-ray data from the Chandra High Energy Transmission Grating (HETG) are presented. Two of the sources, SS Cyg and U Gem, are observed in both quiescent and outburst states, whereas V603 Aql, V426 Oph, WX Hyi, and SU UMa are observed only in quiescence. The fluorescent Fe line is prominent in V603 Aql, V426 Oph, and SS Cyg during quiescence, indicating the presence of a conspicuous reflection component in these sources. The observed equivalent width of the fluorescent Fe line is consistent with reflection from a white dwarf surface that subtends a 2π solid angle at the X-ray source. During the outburst in SS Cyg, the fluorescent line is redshifted by about 2300 km s-1. The Fe XXV triplet at 6.7 keV is found to be dominant in all sources. The value of the G ratio derived from the Fe XXV triplet indicates that the plasma is in collisional ionization equilibrium during the quiescent state. The Fe XXV line is significantly broadened in U Gem and SS Cyg during the outbursts compared to quiescence, indicating the presence of high-velocity material near the white dwarf during the outburst. The ratio of Fe XXVI/XXV indicates a higher ionization temperature during quiescence than in outburst in U Gem and SS Cyg.

Results from a study of high resolution spectra obtained with the Chandra X-ray observatory for a sample of 6 Cataclysmic Variables (CVs) are presented. A global fit approach has been employed to obtain the spectral characteristics of the sources. The line-rich high-resolution spectra of these sources clearly indicate multi-temperature nature of the emitting plasma. Multi-temperature APEC models describe the spectra very well. Detection of significantly broad emission lines, indicates the presence of high velocity gas in SS Cyg and U Gem during the optical Outbursts. (C) 2006 COSPAR. Published by Elsevier Ltd. All rights reserved.

Results from spectral analysis of X-ray data, with the RXTE and X M M-Newton for an asynchronous polar V1432 Aql are presented based on two spectral models - a multi-temperature plasma model and a photo-ionized plasma model. Using a multi-temperature plasma model, the RXTE PCA data are used to constrain the mass of the white dwarf to be 1.2 +/- 0.1 M-circle dot. A strong soft X-ray excess below 0.8 keV, seen with X M M MOS, is modelled by a black body component having temperature of 80-90 eV. The emission lilies seen at 6.7 and 7.0 keV are well fit rising the multi-temperature plasma model, however the 6.4 keV line requires an additional Gaussian component. Two absorbers, one that fully covers the source and another that covers similar to 65% of the source are required. The results from spin phase resolved spectroscopy indicate varying absorption parameters and varying 6.4 keV line flux. X-ray spectral characteristics and their variation with the spin period suggest that V1432 Aql is all unusual hot Polar. The photo-ionized plasma model with a range of column densities for the Fe ions gives a slightly better overall fit and fits all emission line features.

A detailed analysis of X-ray data obtained with ROSAT, ASCA, XMM-Newton, and the Rossi X-ray Timing Explorer (RXTE) for the asynchronous polar V1432 Aquilae is presented. An analysis of Stokes polarimetry data obtained from the South African Astronomical Observatory (SAAO) is also presented. Power spectra from long-baseline ROSAT data show a spin period of 12,150 s along with several frequency components related to the source. However, the second harmonic of the spin period dominates the power spectrum in the XMM-Newton data. For the optical circular polarization, the dominant period corresponds to half the spin period (or its first harmonic). The ROSAT data can be explained as due to accretion onto two hot spots that are not antipodal. The variations seen in the optical polarization and the ASCA and XMM-Newton X-ray data suggest the presence of at least three accretion footprints on the surface of the white dwarf. Two spectral models, a multitemperature plasma model and a photoionized plasma model, are used to understand the spectral properties of V1432 Aql. The data from the RXTE Proportional Counter Array (PCA) with its extended high-energy response are used to constrain the white dwarf mass to 1.2 ± 0.1 M☉ using a multitemperature plasma model. The data from the European Photon Imaging Camera (EPIC) on-board XMM-Newton are well fitted by both models. A strong soft X-ray excess (<0.8 keV) is well modeled by a blackbody component having a temperature of 80-90 eV. The plasma emission lines seen at 6.7 and 7.0 keV are well fitted using the multitemperature plasma model. However, the fluorescent line at 6.4 keV from cold Fe requires an additional Gaussian component. The multitemperature plasma model requires two absorbers: one that covers the source homogeneously and another partial absorber covering ~65% of the source. The photoionized plasma model, with a range of column densities for the Fe ions, gives a slightly better overall fit and fits all emission line features. The intensity and spectral modulations due to the rotation of the white dwarf at a period of 12,150 s require varying absorber densities and a varying covering fraction of the absorber for the multitemperature plasma model. The presence of a strong blackbody component, a rotation period of 12,150 s, modulation of the Fe fluorescence line flux with 12,150 s period, and a very hard X-ray component suggest that V1432 Aql is an unusual polar with X-ray spectral properties similar to that of a soft intermediate polar.

Our multi-epoch observations show that UW Pic undergoes very pronounced changes in accretion geometry. We explain our observations in terms of changing accretion rates of UW Pic coupled with a particular orientation of the system to the observer.

This BoF will be chaired by Paul Barrett and will begin with an introduction to Python in astronomy, be followed by reports of current Python projects, and conclude with a discussion about the current state of Python in astronomy. The introduction will give a brief overview of the language, highlighting modules, resources, and aspects of the language that are important to scientific programming and astronomical data analysis. The closing discussion will provide an opportunity for questions and comments.

We present the results of a 22.5 ks pointed ROSAT PSPC observation of the 3.4-h period eclipsing polar MN Hya (RX J0929.1-2404). The X-ray light curve exhibits a 'double-humped' shape, with a secondary minimum occuring at phi similar to 0.45, a morphology consistent with two-pole accretion. Strong aperiodic flaring activity, with flux enhancements of similar to 6x the quiescent level, is also observed. A pre-eclipse 'dip' occurs in the phase interval phi = 0.87-0.95 with the X-rays becoming harder, indicative of photoelectric absorption by the pre-shock flow. There is also evidence of a secondary spectrally hard 'dip' near phi = 0.45-0.55, which might be associated with a second accretion stream flowing to the other magnetic pole.The X-ray spectrum is best represented by a combination of a similar to 50 eV blackbody and a thermal bremsstrahlung component of kT greater than or similar to 1.6 keV, with a total absorption column of N-H = 2.9 x 10(20)cm(-2).The primary maximum (phi similar to 0.65) has a slightly larger column and normalization compared to the secondary maximum. Although there are few photons, the dip spectrum is very flat in comparison to other phases, and is best represented by a single bremsstrahlung component. This is indicative of the spectral hardening seen in the light curves attributed to photoabsorption. The ratio of unabsorbed bremsstrahlung and blackbody luminosities is similar to 0.1 for the best-fitting average spectral models. This implies a magnetic field strength less than or similar to 30 MG on the basis of the empirical L-hard/L-soft - B relationships, although consideration of the cyclotron flux and aspect effects could allow for an even higher field (less than or similar to 55 MG).

We observed the counterpart to the X-ray source RX J1802.1+1804, an object recently discovered as part of a survey to identify the optical counterparts to ultrasoft X-ray sources in the ROSAT point-source catalog that was subsequently identified as a magnetic cataclysmic variable, with the ultraviolet spectrometers on IUE in low dispersion mode. We report on the results of these observations and interpret our data within the context of other UV spectroscopic studies of magnetic CVs (polars). RX J1802.1+1804 is a relatively bright UV source, with a UV-to-optical flux ratio and emission-line spectrum similar to other well-studied CVs. Our observations insufficiently sample the binary orbit to discern any phase-dependent effects. We found RX J1802.1+1804 to have an unusually large He II λ2733 emission-line strength, and we have also made probable detections of weaker He II lines at 2511, 3203, and possibly 2386 Å, in addition to the more commonly detected He II at 1640 Å. We suggest that RX J1802.1+1804 is thus anomalous in terms of its overall He II emission-line spectrum among the sample. Several lines of O III λλ3047 and 3133 are apparently detected as well, which is unusual for CVs at the signal-to-noise ratio levels obtainable with IUE long-wavelength spectrograph. Given the seemingly rich spectrum of helium and oxygen emission lines, and the known relationship between He II Lyα and the oxygen lines, i.e., the Bowen fluorescence mechanism, we can, in principle, constrain the size and thermodynamics of the emitting region. This analysis suggests that R ~ 109 cm and ne ~ 1011 cm-3. This physical scale is consistent with the line-emission originating in the accretion column rather than in a hot spot on the white dwarf surface.