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Rapid keck spectroscopy of cataclysmic variables  [cached]
Warren Skidmore,Keith Horne,Kevin Pearson,Richard Gomer
Revista mexicana de astronomía y astrofísica , 2004,
Abstract: Presentamos un an alisis de Espectroscop a R apida de Keck de las CVs AM Her (polar) y SS-Cyg (nova enana). Descomponemos los espectros en componentes constantes y variables e identi camos diferentes tipos de variabilidad en AM Her con diferentes escalas caracter sticas de tiempo. Se aislaron la componente variable del ujo del disco de acreci on y las caracter sticas observacionales de una peque~na fulguraci on en SS Cyg.
Probing black hole X-ray binaries with the Keck telescopes  [PDF]
Emilios T. Harlaftis,Alexei V. Filippenko
Physics , 2000, DOI: 10.1117/12.390146
Abstract: The advent of the large effective apertures of the Keck telescopes has resulted in the determination with unprecedented accuracy of the mass functions and mass ratios of faint (R ~ 21 mag) X-ray transients (GS 2000+25, GRO J0422+32, Nova Oph 1977, Nova Vel 1993), as well as constraining the main-sequence companion star parameters and producing images of the accretion disks around the black holes.
X-ray Spectroscopy of Accretion Disks and Stellar Winds in X-Ray Binaries  [PDF]
Duane A. Liedahl,Patrick S. Wojdowski,Mario A. Jimenez-Garate,Masao Sako
Physics , 2001,
Abstract: From hot, tenuous gas dominated by Compton processes, to warm, photoionized emission-line regions, to cold, optically thick fluorescing matter, accreting gas flows in X-ray binaries span a huge portion of the parameter space accessible to astrophysical plasmas. The coexistence of such diverse states of material within small volumes (10^33-10^36 cm^3) leaves X-ray spectroscopists with a challenging set of problems, since all such matter produces various X-ray spectral signatures when exposed to hard X rays. Emission-line regions in X-ray binaries are characterized by high radiation energy densities, relatively high particle densities, and velocities ~1000 km/s. In this article, we describe some recent efforts to generate detailed X-ray line spectra from models of X-ray binaries, whose aims are to reproduce spectra acquired with the ASCA, Chandra, and XMM-Newton observatories. With emphasis on the global nature of X-ray line emission in these systems, the article includes separate treatments of high-mass and low-mass systems, as well as summaries of continuum spectroscopy
Rapid variations of polarization in low-mass X-ray binaries  [PDF]
David M. Russell,Piergiorgio Casella,Rob Fender,Paolo Soleri,Magaretha L. Pretorius,Fraser Lewis,Michiel van der Klis
Physics , 2011,
Abstract: Time-resolved optical and infrared polarimetric observations of black hole and neutron star low-mass X-ray binaries are presented. Data were acquired with the VLT, UKIRT and HIPPO on the SAAO 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.
Identification of 12 High Mass X-Ray Binaries detected by INTEGRAL through NIR photometry and spectroscopy  [PDF]
A. Coleiro,S. Chaty,J. A. Zurita Heras,F. Rahoui,J. A. Tomsick
Physics , 2013,
Abstract: Since it started observing the sky, the INTEGRAL satellite has revealed new categories of High Mass X-ray binaries in our Galaxy. These observations raise important questions on the formation and evolution of such rare and short-living objects. We present here new observations that enable us to reveal or constrain the nature of 15 new INTEGRAL sources. After previous photometric and spectroscopic campaigns of observations in optical and near infrared, new spectroscopy and photometry were performed at ESO in optical/NIR with EMMI and SOFI on the NTT in 2008 and 2010 on a sample of INTEGRAL sources. These observations and precisely the detection of specific features in their spectra allow the identification of such high-energy objects. Our results indicate that: 6 of these objects are Be High-Mass X-ray Binaries (BeHMXBs), 6 are Supergiant High-Mass X-ray Binaries (sgHMXBs) and 3 are still unidentified and need higher resolution data to be completely unveiled.
Optical spectroscopy of 20 Be/X-ray Binaries in the Small Magellanic Cloud  [PDF]
Vallia Antoniou,Despina Hatzidimitriou,Andreas Zezas,Pablo Reig
Physics , 2009, DOI: 10.1088/0004-637X/707/2/1080
Abstract: We present a large sample (20 in total) of optical spectra of Small Magellanic Cloud (SMC) High-Mass X-ray Binaries obtained with the 2dF spectrograph at the Anglo-Australian Telescope. All of these sources are found to be Be/X-ray binaries (Be-XRBs), while for 5 sources we present original classifications. Several statistical tests on this expanded sample support previous findings for similar spectral-type distributions of Be-XRBs and Be field stars in the SMC, and of Be-XRBs in the Large Magellanic Cloud and the Milky Way, although this could be the result of small samples. On the other hand, we find that Be-XRBs follow a different distribution than Be stars in the Galaxy, also in agreement with previous studies. In addition, we find similar Be spectral type distributions between the Magellanic Clouds samples. These results reinforce the relation between the orbital period and the equivalent width of the Halpha line that holds for Be-XRBs. SMC Be stars have larger Halpha equivalent widths when compared to Be-XRBs, supporting the notion of circumstellar disk truncation by the compact object.
Infrared spectroscopy of low-mass X-ray binaries II  [PDF]
R. M. Bandyopadhyay,T. Shahbaz,P. A. Charles,T. Naylor
Physics , 1999, DOI: 10.1046/j.1365-8711.1999.02547.x
Abstract: Using CGS4 on UKIRT, we have obtained 2.00-2.45 micron infrared spectra of a number of low-mass X-ray binaries including Sco X-1, Sco X-2, and GX13+1. Sco X-1 shows emission lines only, supporting our previous conclusion that the spectral type of the evolved secondary must be earlier than G5. Emission lines are also seen in the spectrum of Sco X-2, confirming the identity of the IR counterpart. We report the detection of CO bands in GX13+1 and estimate the most likely spectral type of the secondary to be K5 III. We also find P Cygni type profiles in the Brackett gamma lines of Sco X-1 and GX13+1, indicating the presence of high velocity outflows in these systems. We present spectra of candidate IR counterparts to several other elusive X-ray binaries. Finally, implications for the nature and classification of these systems are discussed.
The Extended Chandra Deep Field-South Survey: Optical spectroscopy of faint X-ray sources with the VLT and Keck  [PDF]
J. D. Silverman,V. Mainieri,M. Salvato,G. Hasinger,J. Bergeron,P. Capak,G. Szokoly,A. Finoguenov,R. Gilli,P. Rosati,P. Tozzi,C. Vignali,D. M. Alexander,W. N. Brandt,B. D. Lehmer,B. Luo,D. Rafferty,Y. Q. Xue,I. Balestra,F. E. Bauer,M. Brusa,A. Comastri,J. Kartaltepe,A. M. Koekemoer,T. Miyaji,D. P. Schneider,E. Treister,L. Wisotski,M. Schramm
Physics , 2010, DOI: 10.1088/0067-0049/191/1/124
Abstract: We present the results of a program to acquire high-quality optical spectra of X-ray sources detected in the E-CDF-S and its central area. New spectroscopic redshifts are measured for 283 counterparts to Chandra sources with deep exposures (t~2-9 hr per pointing) using multi-slit facilities on both the VLT and Keck thus bringing the total number of spectroscopically-identified X-ray sources to over 500 in this survey field. We provide a comprehensive catalog of X-ray sources detected in the E-CDF-S including the optical and near-infrared counterparts, and redshifts (both spectroscopic and photometric) that incorporate published spectroscopic catalogs thus resulting in a final sample with a high fraction (80%) of X-ray sources having secure identifications. We demonstrate the remarkable coverage of the Lx-z plane now accessible from our data while emphasizing the detection of AGNs that contribute to the faint end of the luminosity function at 1.5
High time resolution optical/X-ray cross-correlations for X-ray binaries: anti-correlations and rapid variability  [PDF]
Martin Durant,Tariq Shahbaz,Poshak Gandhi,Remon Cornelisse,Teodoro Munoz-Darias,Jorge Casares,Vik Dhillon,Tom Marsh,Hendrik Spruit,Kieran O'Brien,Danny Steeghs,Rob Hynes
Physics , 2010, DOI: 10.1111/j.1365-2966.2010.17604.x
Abstract: Using simultaneous observations in X-rays and optical, we have performed a homogeneous analysis of the cross-correlation behaviours of four X-ray binaries: SWIFT J1753.5-0127, GX 339-4, Sco X-1, and Cyg X-2. With high time-resolution observations using ULTRACAM and RXTE, we concentrate on the short time-scale, dt<20 s, variability in these sources. Here we present our database of observations, with three simultaneous energy bands in both the optical and the X-ray, and multiple epochs of observation for each source, all with ~second or better time resolution. For the first time, we include a dynamical cross-correlation analysis, i.e., an investigation of how the cross-correlation function changes within an observation. We describe a number of trends which emerge. We include the full dataset of results, and pick a few striking relationships from among them for further discussion. We find, that the surprising form of X-ray/optical cross-correlation functions, a positive correlation signal preceded by an anti-correlation signal, is seen in all the sources at least some of the time. Such behaviour suggests a mechanism other than reprocessing as being the dominant driver of the short-term variability in the optical emission. This behaviour appears more pronounced when the X-ray spectrum is hard. Furthermore, we find that the cross-correlation relationships themselves are not stable in time, but vary significantly in strength and form. This all hints at dynamic interactions between the emitting components which could be modelled through non-linear or differential relationships.
A Method of Mass Measurement in Black Hole Binaries Using Timing and High Resolution X-ray Spectroscopy  [PDF]
A. Vikhlinin
Physics , 1999, DOI: 10.1086/312175
Abstract: In X-ray binaries, several percent of the compact object luminosity is intercepted by the surface of the normal companion and re-radiated through Compton reflection and the K-fluorescence. This reflected emission follows the variability of the compact object with a delay approximately equal to the orbital radius divided by the speed of light. This provides the possibility of measuring the orbital radius and thus substantially refining the compact object mass determination compared to using optical data alone. We demonstrate that it may be feasible to measure the time delay between the direct and reflected emission using cross-correlation of the light curves observed near the Kalpha line and above the K-edge of neutral iron. In the case of Cyg X-1, the time delay measurement is feasible with a 300--1000 ksec observation by a telescope with a 1000 cm^2 effective area near 6.4 keV and with a ~5eV energy resolution. With longer exposures, it may be possible to obtain mass constraints even if an X-ray source in the binary system lacks an optical counterpart.
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