87,557 research outputs found
On the distance and mass-radius relation of neutron stars in X-ray burst sources
No full textWe present constraints on the mass-radius relation for the neutron star in the X-ray burst source 18 by using model spectra for X-ray bursts based on the theory developed by Titarchuk 1994. Under the assumption of isotropic burst emission the derived results exclude the stiffer equations of state of neutron star matter. The theory can be used to derive distances to X-ray burst sources from which only burst luminosities below the Eddington limit are observed
Comparative reasoning in constitutional litigation: functions, methods and selected case law of the German Federal Constitutional Court
No full textThe German Federal Constitutional Court: History, Jurisdiction and Composition.Structure and Style of the Judgments. Comparative Reasoning in Constitutional Litigation: Comparative Law as a “fifth” Method of Interpretation, numbers and statistics and selcted case law. The Affirmative Function of Foreign Case Law. The Dismissive or Distinguishing Function of Foreign Case Law. The Implicit or “hidden” Use of Comparative Reasoning. Questions of Methodology
The Bursting Behavior of 4U 1728-34: Parameters of a Neutron Star and Geometry of a NS-disk system
No full textWe analyze a set of Type I X-ray bursts from the low mass X-ray binary 4U 1728-34, observed with Rossi X-ray Timing Explorer (RXTE). We infer the dependence of the neutron star (NS) mass and radius with respect to the assumed distance to the system using an analytical model of X-ray burst spectral formation. The model behavior clearly indicates that the burster atmosphere is helium-dominated. Our results strongly favor the soft equation of state (EOS) of NS for 4U 1728-34. We find that distance to the source should be within 4.5-5.0 kpc range. We obtain rather narrow constrains for the NS radius in 8.7-9.7 km range and interval 1.2-1.6 Ma for NS mass for this particular distance range. We uncover a temporal behavior of red-shift corrected burst flux for the radial expansion episodes and we put forth a dynamical evolution scenario for the NS accretion disk geometry during which an expanded envelope affects the accretion disk and increases the area of the neutron star exposed to the Earth observer. In the framework of this scenario we provide a new method for the estimation of the inclination angle which leads to the value of approximately 50 degrees for 4U 1728-34
The isolated neutron star X-ray pulsars RX J0420.0–5022 and RX J0806.4–4123 : new X-ray and optical observations
No full textWe report on the analysis of new X-ray data obtained with XMM-Newton and Chandra from two ROSAT-discovered X-ray dim isolated neutron stars (XDINs). RX J0806.4−4123 was observed with XMM-Newton in April 2003, 2.5 years after
the first observation. The EPIC-pn data confirm that this object is an X-ray pulsar with 11.371 s neutron star spin period. The X-ray spectrum is consistent with absorbed black-body emission with a temperature kT = 96 eV and N H = 4 × 10 19 cm −2 without significant changes between the two observations. Four XMM-Newton observations of RX
J0420.0−5022 between December 2002 and July 2003 did not confirm the 22.7 s pulsations originally indicated in ROSAT data, but clearly reveal a 3.453 s period. A fit to the X-ray spectrum using an absorbed black-body model yields kT = 45 eV, the lowest value found from the small group of XDINs and N H = 1.0 × 10 20 cm −2. Including a broad absorption line improves the quality of the spectral fits considerably for both objects and may indicate the presence of absorption features similar to those reported from RBS1223, RX J1605.3+3249 and RX J0720.4−3125. For both targets we derive accurate X-ray positions from the Chandra data and present an optical counterpart candidate for RX J0420.0−5022 with B = 26.6 ± 0.3 mag from VLT imaging
Magister choralis; theoretisch-praktische Anweisung zum Verständnis und Vortrag des authentischen römischen Choralgesanges, bearbeitet von Fr. Xav. Haberl.
No full textActive mode-locking of a neodymium-doped fiber laser using intra-cavity pulse compression
No full textActive mode locking of a Nd3+doped fiber laser with piezoelectrically induced Raman-Nath diffraction modulation ie demonstrated. By using intracavity pulse compression, stable pulses of 2.4-psec length are generated at a wavelength of 1054 nm
Timing analysis of the isolated neutron star RX J0720.4-3125 revisited
No full textWe present a reanalysis of the X-ray data for RX J0720.4-3125 presented in our previous paper, Zane et al., using more data recently available from XMM-Newton and Chandra. This analysis also corrects the ROSAT data used in that paper to the barycentric dynamical time (TDB) system, incorporates the revised XMM-Newton barycentric correction available since then, and corrects the definition of the instantaneous period in the maximum likelihood periodogram search. However, we are now unable to find a single coherent period that is consistent with all ROSAT, Chandra and XMM-Newton data sets. From an analysis of the separate data sets, we have derived limits on the period change of (P)over dot = (1.4 +/- 0.6) x 10(-13) s s(-1) at 99 per cent confidence level. This is stronger than the value presented in Zane et al., but sufficiently similar that their scientific conclusions remain unchanged. We examine the implications in more detail, and find that RX J0720.4-3125 can have been born as a magnetar provided that it has a young age of similar to10(4) yr. A more conservative interpretation is that the field strength has remained relatively unchanged at just over 10(13) G, over the similar to10(6)-yr lifetime of the star
Erstes Buch der Messen /
No full textEditorial notes by F. X. Haberl in German dated 20 Oktober 1880.Added t.p. in Latin (Romae : Apud Alexandrum Gardanum, 1591).For 4-6 voices, unacc.Includes bibliographical references.Cum quatour vocibus: Missa Ecce sacerdos Magnus ; Missa O regem Celi ; Missa Virtute Magna ; Missa Gabriel Arcangelus -- Cum quinque vocibus: Missa ad Cenam Agni providi ; Missa Pro defunctis -- Cum sex vocibus: Missa sine nomine.Mode of access: Internet
Modelling the spin pulse profile of the isolated neutron star RX J0720.4-3125 observed with XMM-Newton
No full textWe model the spin pulse intensity and hardness ratio profiles of the isolated neutron star RX J0720.4-3125 using XMM-Newton data. The observed variation is approximately sinusoidal with a peak-to-peak amplitude of 15%, and the hardness ratio is softest slightly before flux maximum. By using polar cap models we are able to derive maximum polar cap sizes and acceptable viewing geometries. The inferred sizes of the caps turn out to be more compatible with a scenario in which the neutron star is heated by accretion, and place limits on the magnetic field strength. The hardness ratio modulation can then be explained in terms of energy-dependent beaming effects, and this constrains the acceptable models of the emerging radiation to cases in which softer photons are more strongly beamed than harder photons. An alternative explanation in terms of spatially variable absorption co-rotating in the magnetosphere is also discussed
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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