Proceedings of the International Astronomical Union (Proc Int Astron Union)

Publisher: International Astronomical Union, Cambridge University Press (CUP)

Journal description

The Proceedings Series of the International Astronomical Union (IAU) comprises high-quality and timely previews and reviews of fundamental and state-of-the-art astrophysical developments around the world, as presented at some ten IAU-sponsored conferences per year. The organisation of scientific conferences is a key activity of the IAU. The results are recorded in the Proceedings of its Symposia, Colloquia, in its Transactions A and B, and in its Highlights of Astronomy that contains the Proceedings of Joint Discussions held at the triennial General Assemblies of the IAU. Subjects covered by the IAU conferences are fundamental astronomy; the sun and heliosphere; planetary systems, stars; interstellar matter; the galactic system; galaxies and the universe; optical and infrared techniques; radio astronomy; and space and high-energy astrophysics. The Proceedings of these conferences are published under the auspices of the IAU, as important records of the status of those scientific fields. The IAU Proceedings Series is essential reading for both professional astrophysicists and students, for finding comprehensive reviews and for studying new developments in specialized fields.

RG Journal Impact: 0.30 *

*This value is calculated using ResearchGate data and is based on average citation counts from work published in this journal. The data used in the calculation may not be exhaustive.

RG Journal impact history

2019Available summer 2020
20150.14
20140.22
20130.24
20120.36
20110.40
20100.46
20090.43
20080.36
20070.33
20060.26
20050.21
20040.25
20030.26
20020.25
20010.24
20000.18

RG Journal impact over time

RG Journal impact
RG Journal impact over timeGraph showing a linear path with a yearly representation of impact points of the journal

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Websitehttp://journals.cambridge.org/action/displayJournal?jid=IAU
Website descriptionProceedings of the International Astronomical Union website
Other titlesProceedings of the International Astronomical Union (Online), Proceedings series of the International Astronomical Union, IAU proceedings series
ISSN1743-9221
OCLC56894548
Material typeDocument, Periodical, Internet resource
Document typeInternet Resource, Computer File, Journal / Magazine / Newspaper

Publications in this journal

A new class of OH (1720 MHz) masers unaccompanied by main-line transitions have recently been discovered (Frail, Goss and Slysh 1994). These masers lie at the interface between supernova remnants (SNRs) interacting with molecular clouds. We discuss three new aspects of SN masers found in the direction toward the Galactic center: (i) the detection of a new --130 \kms OH (1720 MHz) maser in the southern lobe of the molecular ring at the Galactic center, (ii) the detection of extended OH (1720 MHz) maser emission from W28 accompanying the compact maser sources and (iii) the detection of linear polarization of the brightest OH (1720 MHz) maser in SNR G359.1--0.5.
Spiral galaxies can be affected by interactions in clusters, that also may distort the internal velocity field. If unrecognized from single-slit spectroscopy, this could lead to a wrong determination of the maximum rotation velocity as pointed out by Ziegler et al. (2003). This parameter directly enters into the Tully-Fisher relation, an important tool to investigate the evolution of spiral galaxies. To overcome this problem, we measure the 2D-velocity fields by observing three different slit positions per galaxy using FORS2 at the VLT providing us with full coverage of each galaxy and an adequate spatial resolution. The kinematic properties are compared to structural features determined on the HST/ACS images to assess possible interaction processes. As a next step, the whole analysis will be performed for three more clusters, so that we will be able to establish a high-accuracy TFR for spirals at z~0.5. Comment: 2 pages, 2 figures, going to be published in the proceedings of the IAU Symp. 241, "Stellar Populations as Building Blocks of Galaxies"
We study the color structure of disk galaxies in the Groth strip at redshifts 0.1<z<1.2. Our aim is to test formation models in which bulges form before/after the disk. We find smooth color distributions with gentle outward blueing across the galaxy image: bulges are not distinctly redder than their disks; and bulge colors strongly correlate with global colors. The results suggest a roughly coeval evolution of bulges and disks. About 50% of the nuclei of galaxies with central light excesses above the outer exponential profile hold passively evolving red populations. The remainder 50% are galaxies with central blue colors similar to their disks. They may be bulges in formation, or the central parts of disks with non-exponential surface brightness profiles. Comment: 4 pages, 2 figures, contributed paper to IAU Symposium 245 "Formation and Evolution of Galaxy Bulges", Oxford, 16-20 July 2007
Using our semi-linear inversion method, we measure the mass profile of the lens galaxy in the Einstein ring system 0047-2808. The lens is modelled as a baryonic component following the observed light, embedded in a dark matter generalised NFW halo. The semi-linear method makes full use of the information content in the ring image. We determine an unevolved B-band mass to light ratio for the baryons of 3.05 +0.45 -0.86 h_65 M_sol/L_sol (95% CL), accounting for 65% of the total projected mass within the radius of 1.16'' traced by the ring. This result is obtained without need of dynamical measurements. The inner logarithmic slope of the halo is found to be 0.87 +0.69 -0.61 (95% CL). We find that the halo is fairly well aligned with the light but has only half the ellipticity.
Several macrolensed systems exhibit photometric variability consistent with microlensing due to objects of stellar mass located in the lens. The degree of microlensing amplification is dependent upon the size of the source, with smaller sources being more amplified. In general, amplification of sources larger than an Einstein radius projected onto the source plane is negligible. For the quasar Q2237+0305, a quadrupole image lens (Huchra et al., 1985), this radius is 0.05 pc, larger than the predicted size of a continuum emitting accretion disk, but substantially smaller than the broad line region (Figure 1). This scale difference implies that the continuum will be amplified while the broad line emission remains essentially unchanged during a microlensing event (Sanitt, 1971; Kayser et al., 1986). The broad line emitting region, as a whole, is too large to be microlensed, but substructure on small scales may be significantly amplified. Although the total flux in the line is relatively unchanged, microlensing of substructure can result in changes in the shape of the emission line profiles, and produce measurable shifts in the central wavelength of the line (Nemiroff, 1988; Schneider and Wambsganss, 1990).
The long GRB 050730 observed at redshift z ~ 4 allowed the determination of the elemental abundances for a set of different chemical elements. We use detailed chemical evolution models taking into account also dust production to constrain the star formation history of the host galaxy of this long GRB. For the host galaxy of GRB 050730, we derive also some dust-related quantities and the the specific star formation rate, namely the star formation rate per unit stellar mass. We copare the properties of the GRB host galaxy with the ones of Quasar Damped Lyman Alpha absorbers.
Shortly after the discovery of PSR J1906+0746, some hints of profile variations were already interpreted as first signs of relativistic spin-precession occuring. Using observations from the Nan\c{c}ay, Arecibo and Green Bank Radio Observatories, we report here the measurement of pulse profile and polarimetric variations. Using the Rotating Vector Model, we show that PSR J1906+0746 is likely to be an orthogonal rotator ($\alpha \simeq 80^\circ$). Fitting our polarimetric data to a precession model, we determined the geometry of the pulsar and found a wide misalignment angle ($\delta = 89_{-44}^{+85}$ deg, 95% C.L.), although the uncertainty is large. Assuming this geometry, we constructed the beam maps of both magnetic poles.
The association of PSR B1757-24 and the supernova remnant (SNR) G5.4-1.2 was recently questioned by Thorsett et al. (2002) on the basis of proper motion measurements of the pulsar and the "incorrect" orientation of the vector of pulsar transverse velocity [inferred from the orientation of the cometary-shaped pulsar wind nebula (PWN)]. We showed, however, that the association could be real if both objects are the remnants of an off-centred cavity supernova (SN) explosion.
Many gravitationally lensed quasars exhibit flux ratio "anomalies" that cannot be explained under the hypothesis that the lensing potential is smooth on scales smaller than one kpc. Micro-lensing by stars is a natural source of granularity in the lens potential. The character of the expected fluctuations due to micro-lensing depends sensitively on the relative surface densities of micro-lenses (stars) and smoothly distributed (dark) matter. Observations of flux ratios may therefore be used to infer the ratio of stellar to dark matter along the line of sight -- typically at impact parameters 1.5 times the half light radius. Several recently discovered systems have anomalies that would seem to be explained by micro-lensing only by demanding that 70-90% of the matter along the line of sight be smoothly distributed.
The phenomenon which produces the spectra classified as Seyfert 1.8 or 1.9 is investigated through CCD spectropolarimetry and through analysis of three highly variable objects. The Seyfert 1.9 galaxy IRAS 1958-183 has a highly polarized continuum and a broad H-alpha line which is 30 percent polarized. The variability of NGC 2622, NGC 7603 (= Mrk 530), and Mrk 1018 are studied. The changes in flux of the broad lines and the continuum near H-alpha and H-beta are consistent with changes in the extinction in all cases. Improved IRAS photometry supports the conclusion that most Seyfert 1.8s and 1.9s are normal Seyfert 1s seen through a screen of dust located in or just outside of the broad-line regions. Variability is due to changes in the optical depth of this screen.
We report the discovery of pulsed X-ray emission from the compact object CXOU J112439.1-591620 within the Galactic supernova remnant G292.0+1.8 using the High Resolution Camera on the Chandra X-Ray Observatory. The X-ray period is consistent with the extrapolation of the radio period and spindown rate of PSR J1124-5916. The X-ray pulse is single peaked and broad. There is no optical counterpart to a limit of M_V ~ 26. The pressure in the pulsar wind nebula is considerably less than that in the reverse-shock-heated ejecta and circumstellar medium, indicating that the reverse shock has not yet begun to interact with the nebula.
We present new insights about accretion and ejection physics based on joint RXTE/Chandra HETGS studies of rapid X-ray variability in GRS 1915+105. For the first time, with fast phase-resolved spectroscopy of the rho state, we are able to show that changes in the broadband X-ray spectrum (RXTE) on timescales of seconds are associated with measurable changes in absorption lines (Chandra HETGS) from the accretion disk wind. Additionally, we make a direct detection of material evaporating from the radiation-pressure-dominated inner disk. Our X-ray data thus reveal the black hole as it ejects a portion of the inner accretion flow and then drives a wind from the outer disk, all in a bizarre cycle that lasts fewer than 60 seconds but can repeat for weeks. We find that the accretion disk wind may be sufficiently massive to play an active role in GRS 1915+105, not only in quenching the jet on long timescales, but also in possibly producing or facilitating transitions between classes of X-ray variability. Comment: 3 pages, 1 Figure. Proceedings of IAU Symposium 275 (Jets at all Scales), Buenos Aires, 13-17.09.2010; eds. G. Romero, R. Sunyaev, T. Belloni
Among the topics discussed are: magnetic field reconnection in cosmic plasmas; energy dissipation mechanisms in the solar corona; and the acceleration of runaway electrons and Joule heating in solar flares. Consideration is also given to: the nonlinear evolution of the resistive tearing mode; anomalous transport in current sheets; equilibrium and instability in extragalactic jets; and magnetic field reconnection in differentially rotating accretion disks. Among additional topics discussed are: the creation of high energy electron tails by lower hybrid waves and its connection with type-II and type-III bursts; beam current systems in solar flares; and the spatio-temporal features of microwave emissions of active regions and flares.
The absorption spectra of Apollo 11 fine-grained rocks, 10017 and 10022 are due entirely to pyroxene minerals. Spectral bands due to Fe3+, Fe2+, Cr3+ and Ti4+ and Ti3+ are detected. Single crystals of olivine in rocks 12021 and 12018 show bands due to Fe3+, Fe2+, Cr3+, Ti3+, Mn3+, and Mn2+. Pyroxenes in the same rocks exhibit band maxima of the same cationic species as in the olivines. Spectral shifts are noted due to anisotrophy of the crystal structures. Heating sections 10017, 10022, and 12018 from the rock interiors at 200–225°C for 2 h caused large decreases in the spectral intensity of Fe3+, Cr3+ and Ti3+, indicating the following reaction: $$ \text{Fe}^{\text{3 + }} + \text{Cr}^{\text{3 + }} + \text{Ti}^{\text{3 + }} \to \text{Fe}^{\text{2 + }} + \text{Cr}^{\text{2 + }} + \text{Ti}^{\text{4 + }} $$ This suggests that Fe3+, Cr3+ and (a portion of) Ti3+ are not in equilibrium. It is most probable that they were produced subsequent to the formation of the rocks by a combination of secondary ionization processes following cosmic ray bombardment and by trace radioactivity present in the rocks. An orange glass, 150 µ in diam and 50 µ thick contained in brecciated rock, 10048.44, exhibited 15 identifiable absorption bands related to Fe2+, Cr3+, Ti3+, Mn3+ or Mn2+ ions. Plagioclase in 12021.65 has perfect transmission over the region studied. The limit of Fe3+ is in the order of < 1 ppm and Fe2+, 1000 ppm or less in this plagioclase single crystal of dimensions 0.6 mm × 0.2 mm × 30 µ.
IUE low-dispersion spectra and spectral scans made with the Lick Observatory IDS scanners have been combined for 16 shell stars. Eleven objects can be represented by Kurucz (1979) model atmospheres, although some of them display strong shell-type line spectra. Five among them are known binaries. The six remaining objects display complex spectra. A model involving continuum and line radiation from a hydrogen cloud surrounding the accreting component is proposed. A generalization of this model with optically thick segments of the cloud promises to explain even more exotic objects such as beta Lyrae, W Serpentis and possibly epsilon Aurigae.
Deep spectra of the far-ultraviolet sky background have been obtained by the Voyager 2 Ultraviolet Spectrometer (UVS) in the 500 to 1200 A wavelength range. New diffuse galactic background results, particularly in the 900 to 1100 A region, are presented, which extend the North Galactic Pole results of Holberg (1986) over a range of lower galactic latitudes. Twenty-four lines of sight are analyzed for the presence of residual diffuse continua. Typical upper limits of several hundred photons/cm s A sr are obtained for most lines of sight; however, a faint residual continuum is detected at several low-latitude locations. In Ophiuchus, a diffuse stellarlike continuum is attributed to scattering from interstellar dust.
The giant early-type merger remnant galaxy NGC 1316 is an ideal probe for studying the long-term effects of a major merger on its globular cluster (GC) system, given its spectroscopically derived merger age of 3 Gyr which we reported in a recent paper. Here we report several pieces of photometric evidence showing that the second-generation GCs in NGC 1316 are at an evolutionary phase in between that of luminous GCs found in younger merger remnants such as (e.g.) NGC 7252 and that of `red' GCs found in `normal, old' ellipticals. The observation that massive, second-generation GCs formed during major mergers can survive for at least 3 Gyr provides strong evidence that these clusters can have `normal' mass functions including low-mass stars, and hence that they can survive to reach `old age' similar to those of `normal' ellipticals.
We present an analysis of low-resolution infrared spectra for 25 brown dwarf candidates in the NGC 1333 molecular cloud. Candidates were chosen on the basis of their association with the high column density cloud core, and near-infrared fluxes and colors. We compare the depths of water vapor absorption bands in our candidate objects with a grid of dwarf, subgiant, and giant standards to determine spectral types which are independent of reddening. These data are used to derive effective temperatures and bolometric luminosities which, when combined with theoretical tracks and isochrones for pre-main sequence objects, enable us to estimate masses and ages. Depending on the models considered, a total of 9 to 20 brown dwarfs are identified with a median of age of < 1 Myr.
We investigate the outer halo globular cluster population of NGC 1399. This study uses wide-field imaging of this cluster system, which covers the largest area studied with CCD photometry until now. The cluster system of NGC 1399 is found to extend further than 100 kpc from the galaxy. A population of metal-rich, as well as metal-poor clusters has been identified at these large radii. At radii smaller than 55 kpc the specific frequency of the red cluster system remains constant, while that of the blue clusters increases proportional to $r^{0.8\pm0.2}$. For larger radii, the uncertainty of the galaxy light profile does not permit any reliable statement.
This report summarizes laboratory measurements of atomic wavelengths, energy levels, hyperfine and isotope structure, energy level lifetimes, and oscillator strengths. Theoretical calculations of lifetimes and oscillator strengths are also included. The bibliography is limited to species of astrophysical interest. Compilations of atomic data and internet databases are also included. Papers are listed in the bibliography in alphabetical order, with a reference number in the text.
To set the context of our current exploration of the Moon, it is well to recall: Apollo 11 landed near the equator and was capable of affording the astronauts only a few hours on the lunar surface; Apollo 12 checked out pin-point landing which then permitted going to more difficult, non-equatorial sites; in Apollo 14 enlarged propellant tanks permitted some 42 kg of samples to be brought back. Three more Apollo missions follow Apollo 14. The Apollo missions, complemented by unmanned missions to the various planets, form a program to explore the solar system.
The current report covers the period from the second half of 2003 to the first half of 2011, bringing the Working Group's efforts up to date, and is divided into three main sections covering rotational, vibrational, and electronic spectroscopy. Rather than being exhaustive, space limitations only allow us to highlight a representative sample of work on molecular spectra. Related research on collisions, reactions on grain surfaces, and astrochemistry appear in the report by another Working Group. These also recount recent conferences and workshops on molecular astrophysics.
In order to test the prediction that the compact components in NRAO 140 should appear to separate at a speed exceeding about 4c, further VLBI observations of NRAO 140 at 2.8 cm were obtained in February 1981 and June 1981. The correlated flux densities and closure phases show clear, systematic changes compared with April 1980 data that are modeled very well by an increase in the separation of the compact components corresponding to velocities of separation ranging from 6.7c to 12c for cosmological distances and H(0) = 50 and q(0) = 0. When H(0) = 100 and q(0) = 1, the range is 2.1c to 3.7c. From these results, a prescription for the determination of upper limits to the cosmological parameters H(0) and q(0) is outlined.
The narrow line QSO PG1211+143 has been a focus of recent attempts to understand the soft excess in AGN, while the 2001 XMM-Newton observation of this luminous AGN also provided evidence for a massive and energetic outflow. Here we consider a physical link between the energetic outflow and the variable soft excess. Comment: to be published in 'Black Holes: from Stars to Galaxies - across the Range of Masses. Proceedings IAU Symposium No. 238, 2006. V.Karas and G.Matt, eds
In 2011, Bailes et al. reported on the discovery of a detached companion in a 131 minute orbit around PSR J1719-1438, a 173 Hz millisecond pulsar. The combination of the very low mass function and such a short orbital period is unique. The discoverers suggested that the progenitor system could be an ultracompact X-ray binary (UCXB), which is a binary with a sub-hour orbital period in which a (semi-)degenerate donor fills its Roche lobe and transfers mass to a neutron star. The standard gravitational-wave driven UCXB scenario, however, cannot produce a system like PSR J1719-1438 as it would take longer than the age of the Universe to reach an orbital period of 131 min. We investigate two modifications to the standard UCXB evolution that may resolve this discrepancy. The first involves significant heating and bloating of the donor by pulsar irradiation, and in the second modification the system loses orbital angular momentum via a fast stellar wind from the irradiated donor, additional to the losses via the usual gravitational wave radiation. In particular a donor wind is effective in accelerating orbital expansion, and even a mild wind could produce the 131 minute period within the age of the Universe. We note that UCXBs could be an important class of progenitors of solitary millisecond radio pulsars.
We present Spitzer 8 micron transit observations of the extrasolar planet system HD 149026. At this wavelength, transit light curves are weakly affected by stellar limb-darkening, allowing for a simpler and more accurate determination of planetary parameters. We measure a planet-star radius ratio of R_p/R_s = 0.05158 +/- 0.00077, and in combination with ground-based data and independent constraints on the stellar mass and radius, we derive an orbital inclination of i = 85.4 +0.9/-0.8 deg. and a planet radius of 0.755 +/- 0.040 Jupiter radii. These measurements further support models in which the planet is greatly enriched in heavy elements. Comment: To appear in the Proceedings of the 253rd IAU Symposium: "Transiting Planets", May 2008, Cambridge, MA
Radio observations have clearly demonstrated that the kinematic twin-jet model (Milgrom 1979; Abell and Margon 1979) is the correct description of the general behavior of SS433 and have determined the orientation parameters that could not be obtained from the optical observations (Gilmore and Seaquist 1980; Hjellming and Johnston 1981 (HJ); Niell, Lockhart, and Preston 1981 (NLP)). Figure 1 shows the observed position angle of the radio jet at a distance of approximately 0′.′15 from the core during the period 1979 May to 1981 May as determined from our VLBI measurements at 2.3 GHz. The mean position angle is 98°±2° for a 20° half-angle cone of precession about an inclination of 79° to the line of sight. The phase is consistent with the expected propagation time out to 0′.′15 (1016cm) at a speed of 0.26c for a distance to SS433 of 5 kiloparsecs (HJ; NLP).
The salient features of quasi-periodic oscillations (QPOs) observed in type 2 bursts and in the persistent emission from the rapid burster MXB 1730-335 are discussed. In addition, a brief review is given of the models that have recently been proposed to explain high-frequency QPOs observed in several bright low-mass X-ray binaries. Little is known about the mechanism(s) of the QPOs, not even whether they are magnetospheric in origin. However, some of the proposed ideas could well be relevant to the various rather complex aspects of the QPOs. It is likely that more than one mechanism is at work.
KS 1741-293 is a transient neutron star low-mass X-ray binary that is located at an angular distance of ~20' from the Galactic center. We map out the historic activity of the source since its discovery in 1989, characterize its most recent X-ray outbursts observed with Swift (2007, 2008, 2010, and 2011), and discuss its quiescent X-ray properties using archival Chandra data. KS 1741-293 is frequently active, exhibiting outbursts that typically reach a 2-10 keV luminosity of Lx~1E36 (D/6.2 kpc)^2 erg/s and last for several weeks-months. However, Swift also captured a very short and weak accretion outburst that had a duration of <4 days and did not reach above Lx~5E34 (D/6.2 kpc)^2 erg/s. The source is detected in quiescence with Chandra at a 2-10 keV luminosity of Lx~2.5E32 (D/6.2 kpc)^2 erg/s.
Omnidirectional cosmic gamma ray flux near one MeV observed by ERS-18 satellite, plotting spectral energy distribution
During the 1971 opposition of Mars, new infrared spectra covering the region 1800-3200 per cm were taken at a resolution of 0.095 per cm using a Connes'-type Fourier spectrometer on a 2.7 m telescope. No new trace constituents have, as yet, been found in the spectra, but several previously unobserved combination of isotopic bands of CO2 are visible. It has also been found possible to fit fairly well defined kinetic temperatures and Bond albedos to the data. The kinetic temperatures have been determined by a new technique. It is found that the albedo at 33 deg phase, which was determined a few days after the onset of the great dust storm of 1971, was significantly higher than for the clear atmosphere. The explanation for this phenomenon must await detailed radiative transfer calculations for a dust-laden atmosphere.
The original sunspot observations by Heinrich Samuel Schwabe of 1825-1867 were digitized and a first subset of spots was measured. In this initial project, we determined more than 14 000 sunspot positions and areas comprising about 11% of the total amount of spots available from that period. The resulting butterfly diagram has a typical appearance, but with evident north-south asymmetries.
An analysis of polar-motion data for 125 years, spanning the period from 1846 to 1971, is shown to indicate that a model with at least two degrees of freedom is necessary for a determination of the polar motion. The natural frequencies of the earth are 428 and 437.5.
This report summarizes laboratory measurements of atomic wavelengths, energy levels, hyperfine and isotope structure, energy level lifetimes, and oscillator strengths. Theoretical calculations of lifetimes and oscillator strengths are also included. The bibliography is limited to species of astrophysical interest. Compilations of atomic data and internet databases are also included. Papers are listed in the bibliography in alphabetical order, with a reference number in the text.
To set the context of our current exploration of the Moon, it is well to recall: Apollo 11 landed near the equator and was capable of affording the astronauts only a few hours on the lunar surface; Apollo 12 checked out pin-point landing which then permitted going to more difficult, non-equatorial sites; in Apollo 14 enlarged propellant tanks permitted some 42 kg of samples to be brought back. Three more Apollo missions follow Apollo 14. The Apollo missions, complemented by unmanned missions to the various planets, form a program to explore the solar system.
The current report covers the period from the second half of 2003 to the first half of 2011, bringing the Working Group's efforts up to date, and is divided into three main sections covering rotational, vibrational, and electronic spectroscopy. Rather than being exhaustive, space limitations only allow us to highlight a representative sample of work on molecular spectra. Related research on collisions, reactions on grain surfaces, and astrochemistry appear in the report by another Working Group. These also recount recent conferences and workshops on molecular astrophysics.
In order to test the prediction that the compact components in NRAO 140 should appear to separate at a speed exceeding about 4c, further VLBI observations of NRAO 140 at 2.8 cm were obtained in February 1981 and June 1981. The correlated flux densities and closure phases show clear, systematic changes compared with April 1980 data that are modeled very well by an increase in the separation of the compact components corresponding to velocities of separation ranging from 6.7c to 12c for cosmological distances and H(0) = 50 and q(0) = 0. When H(0) = 100 and q(0) = 1, the range is 2.1c to 3.7c. From these results, a prescription for the determination of upper limits to the cosmological parameters H(0) and q(0) is outlined.
The narrow line QSO PG1211+143 has been a focus of recent attempts to understand the soft excess in AGN, while the 2001 XMM-Newton observation of this luminous AGN also provided evidence for a massive and energetic outflow. Here we consider a physical link between the energetic outflow and the variable soft excess. Comment: to be published in 'Black Holes: from Stars to Galaxies - across the Range of Masses. Proceedings IAU Symposium No. 238, 2006. V.Karas and G.Matt, eds
In 2011, Bailes et al. reported on the discovery of a detached companion in a 131 minute orbit around PSR J1719-1438, a 173 Hz millisecond pulsar. The combination of the very low mass function and such a short orbital period is unique. The discoverers suggested that the progenitor system could be an ultracompact X-ray binary (UCXB), which is a binary with a sub-hour orbital period in which a (semi-)degenerate donor fills its Roche lobe and transfers mass to a neutron star. The standard gravitational-wave driven UCXB scenario, however, cannot produce a system like PSR J1719-1438 as it would take longer than the age of the Universe to reach an orbital period of 131 min. We investigate two modifications to the standard UCXB evolution that may resolve this discrepancy. The first involves significant heating and bloating of the donor by pulsar irradiation, and in the second modification the system loses orbital angular momentum via a fast stellar wind from the irradiated donor, additional to the losses via the usual gravitational wave radiation. In particular a donor wind is effective in accelerating orbital expansion, and even a mild wind could produce the 131 minute period within the age of the Universe. We note that UCXBs could be an important class of progenitors of solitary millisecond radio pulsars.
We present Spitzer 8 micron transit observations of the extrasolar planet system HD 149026. At this wavelength, transit light curves are weakly affected by stellar limb-darkening, allowing for a simpler and more accurate determination of planetary parameters. We measure a planet-star radius ratio of R_p/R_s = 0.05158 +/- 0.00077, and in combination with ground-based data and independent constraints on the stellar mass and radius, we derive an orbital inclination of i = 85.4 +0.9/-0.8 deg. and a planet radius of 0.755 +/- 0.040 Jupiter radii. These measurements further support models in which the planet is greatly enriched in heavy elements. Comment: To appear in the Proceedings of the 253rd IAU Symposium: "Transiting Planets", May 2008, Cambridge, MA
Radio observations have clearly demonstrated that the kinematic twin-jet model (Milgrom 1979; Abell and Margon 1979) is the correct description of the general behavior of SS433 and have determined the orientation parameters that could not be obtained from the optical observations (Gilmore and Seaquist 1980; Hjellming and Johnston 1981 (HJ); Niell, Lockhart, and Preston 1981 (NLP)). Figure 1 shows the observed position angle of the radio jet at a distance of approximately 0′.′15 from the core during the period 1979 May to 1981 May as determined from our VLBI measurements at 2.3 GHz. The mean position angle is 98°±2° for a 20° half-angle cone of precession about an inclination of 79° to the line of sight. The phase is consistent with the expected propagation time out to 0′.′15 (1016cm) at a speed of 0.26c for a distance to SS433 of 5 kiloparsecs (HJ; NLP).
The salient features of quasi-periodic oscillations (QPOs) observed in type 2 bursts and in the persistent emission from the rapid burster MXB 1730-335 are discussed. In addition, a brief review is given of the models that have recently been proposed to explain high-frequency QPOs observed in several bright low-mass X-ray binaries. Little is known about the mechanism(s) of the QPOs, not even whether they are magnetospheric in origin. However, some of the proposed ideas could well be relevant to the various rather complex aspects of the QPOs. It is likely that more than one mechanism is at work.
KS 1741-293 is a transient neutron star low-mass X-ray binary that is located at an angular distance of ~20' from the Galactic center. We map out the historic activity of the source since its discovery in 1989, characterize its most recent X-ray outbursts observed with Swift (2007, 2008, 2010, and 2011), and discuss its quiescent X-ray properties using archival Chandra data. KS 1741-293 is frequently active, exhibiting outbursts that typically reach a 2-10 keV luminosity of Lx~1E36 (D/6.2 kpc)^2 erg/s and last for several weeks-months. However, Swift also captured a very short and weak accretion outburst that had a duration of <4 days and did not reach above Lx~5E34 (D/6.2 kpc)^2 erg/s. The source is detected in quiescence with Chandra at a 2-10 keV luminosity of Lx~2.5E32 (D/6.2 kpc)^2 erg/s.
Omnidirectional cosmic gamma ray flux near one MeV observed by ERS-18 satellite, plotting spectral energy distribution
During the 1971 opposition of Mars, new infrared spectra covering the region 1800-3200 per cm were taken at a resolution of 0.095 per cm using a Connes'-type Fourier spectrometer on a 2.7 m telescope. No new trace constituents have, as yet, been found in the spectra, but several previously unobserved combination of isotopic bands of CO2 are visible. It has also been found possible to fit fairly well defined kinetic temperatures and Bond albedos to the data. The kinetic temperatures have been determined by a new technique. It is found that the albedo at 33 deg phase, which was determined a few days after the onset of the great dust storm of 1971, was significantly higher than for the clear atmosphere. The explanation for this phenomenon must await detailed radiative transfer calculations for a dust-laden atmosphere.
The original sunspot observations by Heinrich Samuel Schwabe of 1825-1867 were digitized and a first subset of spots was measured. In this initial project, we determined more than 14 000 sunspot positions and areas comprising about 11% of the total amount of spots available from that period. The resulting butterfly diagram has a typical appearance, but with evident north-south asymmetries.
An analysis of polar-motion data for 125 years, spanning the period from 1846 to 1971, is shown to indicate that a model with at least two degrees of freedom is necessary for a determination of the polar motion. The natural frequencies of the earth are 428 and 437.5.
We present the surface photometry of star clusters in the nearby dwarf elliptical galaxies NGC 185 and NGC 205, obtained from deep HST WFPC2 F555W (V) and F814W (I) images. We have obtained surface brightness and color profiles of six star clusters in NGC 185, seven star clusters in NGC 205, and one recently discovered non-stellar object in NGC 205. The surface brightness profiles of ten star clusters are fitted well by the King model, and those of four star clusters are fitted well by the power-law. Three out of ten star clusters fitted well with King model show signs of tidal tails.
The WIYN open cluster study (WOCS) has been working to yield precise magnitudes in the Johnson-Kron-Cousins UBVRI system for all stars in the field of a selection of ``prototypical'' open clusters. Additionally, WOCS is using radial velocities to obtain orbit solutions for all cluster binary stars with periods of less than 1000 days. Recently, WOCS is being expanded to include the near-infrared JHK_s (deep ground-based plus 2MASS) and mid-infrared ([3.6], [4.5], [5.8], [8.0]) photometry from Spitzer/IRAC observations. This multi-wavelength data (0.3--8.0 microns) allows us photometrically to identify binaries, with mass ratios from 1.0--0.3, across a wide range of primary masses. The spectral energy distribution (SED) fitter by Robitaille et al. (2007) is used to fit the fluxes of 10--12 bands, converted from the observed magnitudes, to Kurucz stellar models. Using this photometric technique, we find that NGC 188 has a binary fraction of 36--49% and provide a star-by-star comparison to the WOCS radial velocity-based binary study. Comment: 2 pages, 2 figures, Conference Proceedings from "Dynamical Evolution of Dense Stellar Systems'', IAU Symposium 246, Eds. E. Vesperini, M. Giersz, & A. Sills

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