bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of New Analysis Method for Mapping Observations of Clusters of Galaxies
Authors: Kikuchi K. , Ohashi T. , Ezawa H. , Hirayama M. , Honda H. , Shibata R.
Published: July 2016

Mapping observations of nearby large-extended clusters of galaxies (Coma, Perseus, Virgo, etc.) are being performed with ASCA. Such clusters allow us to map physical parameters of hot gas in the clusters, such as temperature, metal abundance, and X-ray surface brightness. To determine such parameters at each part of a cluster, one should take careful care of X-ray contamination from outside of a pointed field, which is mainly due to “stray-light” X-rays (Honda et al. 1997). For this reason, the only way to obtain the distribution of hot gas parameter is to process the whole cluster data in a self-consistent way. For this purpose, we are developing the new analysis system called TERRA.
Uncertainty in Mass Determination of Galaxy Clusters due to the Bulk Motion of Intracluster Medium
Authors: Takizawa M. , Mineshige S.
Published: July 2016

Determination of the mass of cluster of galaxies (CG) is very important mainly because it relates to determination of cosmological density parameter (Ω0).
ASCA Observation of Groups of Galaxies
Authors: Tawara Y. , Sato S. , Furuzawa A. , Yamashita K. , Isobe K. , Kumai Y.
Published: July 2016

Based on the ASCA observations, the X-ray features like spatial extentions and spectral properties of their component were analyzed for nearby four compact groups of galaxies; HCG62, NGC2300 group, HCG42 and HCG48. We found wide variety in their X-ray features. One of the brightest source of HCG62 shows the presence of cool component and enhanced abundance at its center, while HCG42 shows less extention and low abundance ratio of α-element to iron. For NGC 2300 group, we also found interesting feature which may be related to galaxy-intragroup medium interaction.
Matter Distribution in the Galaxy Clusters A 539 and A 2319
Authors: Trèvese D. , Cirimele G. , de Simone M.
Published: July 2016

We performed a combined X-ray and optical analysis of the two clusters A539 and A2319, based on ROSAT PSPC 0.4-2.4 keV images of the public archive and F band photometry from microdensitometric scans of Palomar 48 inch plates (Trèvese et al. 1992, A&AS, 94, 327). Assuming spherical symmetry and following the methods adopted in Cirimele, Nesci, and Trèvese (1997, ApJ, 475, 11 (CNT97)) we derived the radial distribution of gas and galaxy densities ρgasand ρgaland we have computed the morphological parameter βxo≡dln ρgas(r)/dln ρgal(r), introduced in CNT97. This allows to check the validity of the hydrostatic equilibrium condition, which reads, for an isotropic and uniform velocity distribution of r.m.s. dispersion σr. In the case of A539, adopting σr=629 km s−1from Fadda et al. (1996, ApJ, 473, 670) and T=1.57 keV David et al. (1996, ApJ, 473, 692), we obtained marginally consistent values of βspec= 1.54±0.50 and βxo=1.08±0.11. In the case of A2319 we took into account the presence of the secondary component A2319B (Oegerle et al. 1995, AJ, 110, 32) and the temperature gradient (Markevitch M. 1996, ApJ, 465, L1). The resulting radial increase of βspecis consistent with that of (βxo(r) +dlnT(r)/dln ρgal), suggesting that the hydrostatic equilibrium holds also in the presence of a temperature gradient. The radial distribution of the total binding mass, the mass in galaxies and intergalactic gas show that in both clusters the gas mass profile is steeper than galaxies and total masses consistently with our previous results (CNT97). Adopting a constant gas temperature, the relevant baryon fractions are larger than 20 %, adding new evidence to the “baryon catastrophe”. Taking into account the radial decrease of gas temperature, the baryon fraction is further increased. This implies that either Ωo< 0.25, or that large halos of dark matter surround galaxy clusters, as suggested by White & Fabian (1995, MNRAS, 273, 72).
Development of STJ as a New X-Ray Detector
Authors: Yamasaki N. Y. , Ohashi T. , Kikuchi K. , Miyazaki H. , Rokutanda E. , Kushino A. , Kurakado M.
Published: July 2016

STJs are promising X-ray detectors as high energy resolution spectrometers due to the small excitation energy to break the Cooper pairs to product detectable electrons. The expected energy resolution is about 5 eV for a 6 keV incident X-rays (see review by Kraus et al. and Esposito et al.). We have developed a large area (178 × 178μm2) Nb/Al/AlOX/Al/Nb STJs (Kurakado et al. 1993) and series-connected STJs with a position resolution of 35μm for α particles (Kurakado 1997) at Nippon Steel Corporation. As a focal plane detector in future X-ray missions, we are developing STJs whose targert characteristics are; an energy resolution of 20 eV at 6keV, an effective area of 1 cm2, and position resolution of 100μm.
Spin-Down of Neutron Stars and Compositional Transitions in the Cold Crustal Matter
Authors: Iida Kei , Sato Katsuhiko
Published: July 2016

Transitions of nuclear compositions in the crust of a neutron star induced by stellar spin-down are evaluated at zero temperature. We construct a compressible liquid-drop model for the energy of nuclei immersed in a neutron gas, including pairing and shell correction terms, in reference to the known properties of the ground state of matter above neutron drip density, 4.3 × 1011 g cm−3. Recent experimental values and extrapolations of nuclear masses are used for a description of matter at densities below neutron drip. Changes in the pressure of matter in the crust due to the stellar spin-down are calculated by taking into account the structure of the crust of a slowly and uniformly rotating relativistic neutron star. If the initial rotation period is of the order of milliseconds, these changes cause nuclei, initially being in the ground-state matter above a mass density of about 3 × 1013 g cm−3, to absorb neutrons in the equatorial region where the matter undergoes compression, and to emit them in the vicinity of the rotation axis where the matter undergoes decompression. Heat generation by these processes is found to have significant effects on the thermal evolution of old neutron stars with low magnetic fields; the surface emission predicted from this heating is compared with the ROSAT observations of X-ray emission from millisecond pulsars and is shown to be insufficient to explain the observed X-ray luminosities (Iida and Sato, 1997).
A Model for a Thin Magnetised Disc in LMC X-3
Authors: Hoyng P.
Published: July 2016

A model for the stationary radial distribution of the magnetic energy-stress tensor  in a standard thin disc is presented, with allowance for magnetic torques and dissipation, see Fig. 1. The model is an extension of earlier work by Schramkowski et al. (1996). For LMC X-3, 1/2 reaches ~ 4 × 105 G near the inner edge of the disc, and the magnetic pressure is much smaller than the sum of gas and radiation pressure.
Disk Oscillations as the Origin of Quasi-Periodic Oscillations in Black Hole Candidates
Authors: Yamasaki T. , Mineshige S. , Kato S.
Published: July 2016

Quasi-periodic oscillations (QPOs) of a few Hz are observed in the very high state of some black hole candidates (GX 339-4 and GS 1124-68). This is the Kepler frequency at the radius of a few hundred Schwarzschild radii. As a possible mechanism of the QPOs in these objects, the trapped oscillations in the accretion disks are considered. The trapped oscillations of the disks were investigated by several authors. They studied the trapped oscillations in the standard radiative cooling-dominated disks. Recently, the advection-dominated accretion flow is considered, as a possible model to explain the hard X-ray spectra of the black hole candidates or the active galactic nuclei. In particular, in the very high state of some black hole candidates, the spectrum can be explained by the disk-corona model which comprises the cold standard accretion disk and the advection-dominated corona above the cold disk. We thus investigated the trapped axi-symmetric oscillations in the advection-dominated corona by the global linear analysis.
ASCA Observations of the Superluminal Jet Source GRS1915+105
Authors: Ebisawa Ken , Takeshima T. , White N. E. , Kotani T. , Dotani T. , Ueda Y. , Harmon B. A. , Robinson C. R. , Zhang S. N. , Paciesas W. S. , Tavani M. , Foster R.
Published: July 2016

GRS1915+105 is an extraordinary X-ray transient which exhibits superluminal radio jets. In this paper, ASCA observations of the GRS1915+105 conducted from 1994 to 1997 are reported. Observations are carried out on the following dates each for ~ 20 ksec exposure; Sep 27 1994, April 20 1995, Oct 23 1996 and Apr 25 1997.
Rapid Hard X-Ray Variability in GRO J0422+32
Authors: van der Hooft F. , van Paradijs J. , Van Der Klis M. , Kouveliotou C. , Crary D.J. , Finger M.H. , Rubin B.C. , Harmon B.A. , Fishman G.J. , Lewin W.H.G.
Published: July 2016

The soft X-ray transient (SXT) GRO J0422+32 (Nova Persei 1992) was detected with the Burst And Transient Source Experiment (BATSE) on board the CGRO on 1992 August 5 (Paciesas et al. 1992) (Truncated Julian Day [TJD] 8839). The source intensity of GRO J0422+32 increased rapidly, reaching a flux of ~ 3 Crab (40-230 keV) within days after its first detection (Harmon et al. 1992). Hereafter, the X-ray intensity of the source decreased exponentially with a decay time of ~ 43 days (Vikhlinin et al. 1995). A secondary maximum of the X-ray intensity was reached at TJD 8978, 139 days after the first detection of the source. The daily averaged flux history of GRO J0422+32 in the 40-150 keV energy band is presented in Figure 1.
Determination of NGC 4151 Nucleus Mass from Parameters of Narrow Satellites of Broad Lines
Authors: Bochkarev N.G.
Published: July 2016

The paper considers the possibility of AGN mass estimation from observations of spectral lines emitted by jets. Jets are a typical for AGNs.

Similar to SS433 the inner parts of AGN jets may emit spectral lines. 88433 spectra show that jet lines are week in comparison with those of slowly outflowing gas. Consequently the proper time for AGNs jet lines observations is the deep brightness minima (so-called transition from Sy1 type to Sy2 type of spectra). It is possibly the only chance for jet lines observations, because on the Sy1 stage gas surrounding the central object can. be optically thick in the broad lines wings or at least light up the week jet lines. The only well studied case of A(;N transition from Sy1 to Sy2 with evidence of jets is NGC 4151 when this galaxy was in a deep minimum of brightness during the 1984-1987.
X-Ray Properties of High-Z Radio-Quiet Quasars: ASCA Observations
Authors: Cappi M. , Matsuoka M. , Vignali C. , Comastri A. , Mihara T. , Otani C. , Palumbo G.G.C. , Xue S.J.
Published: July 2016

The first-ever high energy (~ 1-30 keV) X-ray spectra of three z ~ 2 radio-quiet quasars (RQQs) are presented. If confirmed, the most interesting result is the marginal, but consistent, evidence for FeKα emission lines in at least two of the sources. Further ASCA observations of high-z RQQs are needed for firm conclusions.
ASCA Observations of Narrow Line Seyfert 1 Galaxies
Authors: Hayashida K.
Published: July 2016

Study of nine Narrow Line Seyfert 1 galaxies (NLS1) observed with ASCA is presented. The X-ray spectra are fitted with a two component model. The soft component can be represented by a blackbody model with kT~100eV. To make the observed luminosity below the Eddignton limit, we have to assume the emission region has a size much smaller than 3Rs. The X-ray variabilities of the NLS1s have systematically shorter time scale than the typical (broad line) Seyferts 1 (BLS1), which suggests lower black hole masses in the NLS1s.

We also study the the X-ray spectral structure around 1.1 keV, which has been reported for some NLS1s. Although the structure has been interpreted as an absorption feature, we propose an alternative model employing emission lines. One possible origin of the emission lines is preprocessing from a highly ionized accretion disk.
How Unbiased is a [OIII]λ5007-Bright Sample?
Authors: Ueno Shiro , Law-Green J. Duncan , Awaki Hisamitsu , Koyama Katsuji
Published: July 2016

We have observed a dozen bright Seyfert 2's selected by their [OIII]λ5007 emission line flux (Ueno et al 1996, Awaki et al 1996). We chose this to be a flux-limited sample free from X-ray selection effects such as intrinsic absorbing columns (NH) and differences in viewing angle (Mulchaey et al 1994). Is it genuinely free from these selection effects? To investigate this, we compare the [OIII] luminosity of various Seyfert 2 galaxies. For this paper, we assume the Hubble constant to be H0 = 50km s−1 Mpc−1.
BeppoSAX Observation of the Quasar 3C273
Authors: Mineo T. , Cusumano G. , Guainazzi M. , Grandi P.
Published: July 2016

The quasar 3C273 was observed from 18th to 21st July 1996 with the Narrow Field Instruments (NFIs) onboard BeppoSAX satellite (Boella et al 1997). The total exposure time was 12 ksec for LECS, 131 ksec for MECS and 64 ksec for HPGSPC and PDS.
Change in the Warm Absorber in MR 2251-178
Authors: Otani C. , Kii T. , Miya K.
Published: July 2016

We report the results of the search for the change in the warm absorber of the quasar MR 2251-178 with ASCA. We detected its change along with the X-ray intensity change. In the bright phase in 1993, its X-ray spectra showed the absorption edge features by OVII and OVIII edges. In contrast, in the medium intensity (in 1996), the absorption apparently increased and the edge energy was shifted to the lower energy. These results are well explained by the ionization change of the same absorber. The timescale of the change requires moderately high density and the location to be nearer to the center than the Narrow Line Region. We briefly discuss the stability of the warm absorber.
ASCA Observations of the Quasar Concentration 1338+27
Authors: Yamada T. , Ueda Y. , Takahashi T. , Mihara T. , Kawai N. , Ishisaki Y.
Published: July 2016

There are several regions where a group of quasars are significantly clustered in the physical space. In the “CFHT grens survey” conducted by Crampton et al. (Crampton et al. 1989 and references therein), the 23 quasars between z=1.036 and 1.185 were found to be clustered over ~ 2° × 2° in the region denoted as 1338+27 At the mean redshift zave = 1.113, the angular extent 6000 arcsec (CHH89) of this cluster corresponds to 60 h−1Mpc(q0 = 0.5) and the dispergion of the redshift λz = 0.044 to 45 h−1Mpc.
The Black Hole Grazer
Authors: Taniguchi Y. , Kaburaki O.
Published: July 2016

We propose an alternative model for the powering of active galactic nuclei (AGN), based on the assumption that all AGN have experienced mergers. In our model (Kaburaki and Taniguchi 1996; Taniguchi and Kaburaki 1996), a close pair of super-massive black holes (the black hole grazer) orbit one another in a plane roughly perpendicular to the galactic center magnetic field. The orbital motion induces surface charges on the black holes which produce an electric field. This field is strong enough to cause pair creation so that the Roche lobe of the binary system is filled with pair plasmas. Rigid-body rotation of the Roche-lobe magnetosphere drives electrodynamically a powerful synchrotron jet emanating from the center of mass of the binary. Furthermore, a pair of equatorial jets flow from the outer Lagrangian points of the binary system. Although these jets are not so collimated, they interact with the accreting gas ring formed around the orbital plane of the binary, causing broad line regions or H2O maser emission regions (Taniguchi et al. 1996). In addition to the primary jet, two secondary jets are also driven by local accretion disks around the two black holes. The interaction among the primary and the secondary jets may explain detailed jet morphology observed by VLBI facilities.
Introductory overview
Authors: Andersen J.
Published: July 2016

The subject of this meeting is the confrontation between precise observational and theoretical determinations of fundamental stellar properties. Its goal is to better define the limits of our present understanding of the structure and evolution of stars, and of our own and other galaxies. That goal is not approached by keeping to the “safe” side of the border: The areas where significant disagreement is found between the best observations and the best theories also show the directions where progress is to be made.
Review of the ultraviolet flux calibration
Authors: Kruk Jeffrey W.
Published: July 2016

The practical difficulties in performing laboratory calibrations of instruments at ultraviolet wavelengths are considerably greater than at visible wavelengths, and the concommitant uncertainties are greater as well. In recent years theoretical models of white dwarf atmospheres have been adopted as UV flux standards, with impressive results. In this review, I will discuss the methodology of laboratory flux calibrations in the UV, the internal consistency and potential shortcomings of calibrations based on white dwarf model atmospheres, recent laboratory results, and future prospects.
The colours of the Sun
Authors: Taylor B. J.
Published: July 2016

In this paper, arguments are developed for treating (R–I)C as the most important colour to be derived for the Sun. The solar value of (R - I)C is then found to be 0.335 ± 0.002 mag. This result updates a counterpart given by Taylor in 1992.
Precise stellar mass and mass-luminosity data
Authors: Andersen J.
Published: July 2016

Recent progress in observing and data reduction methods for precise mass and mass-luminosity determinations in binary systems are briefly reviewed. The foundations appear to have been laid for a new burst of accurate data. Detailed model simulations of the individual systems are the best way to use these data to critically test the theoretical models and advance our understanding of the evolution of single and binary stars.
The stellar temperature scale from angular diameters and flux distributions
Authors: Booth A.J.
Published: July 2016

The current situation for the measurement of effective temperatures from interferometrically determined angular diameters and spectrophometry in the UV, visible and IR is considered. Accuracies and reliabilities of the resulting temperatures are assessed and coverage of stellar types is discussed.
Stellar parameters in the bulge cluster NGC 6553
Authors: Barbuy B. , Ortolani S. , Bica E. , Renzini A. , Guarnieri M.D.
Published: July 2016

Globular clusters in the Galactic bulge form a flattened system, extending from the Galactic center to about 4.5 kpc from the Sun (Barbuy et al. 1997). A study of abundance ratios in these clusters is very important for a more complete understanding of the bulge formation. In this work we present a spectroscopic analysis of individual stars in NGC 6553. This cluster is a key one because it is located at d⊙ ≍ 5.1 kpc, therefore relatively close to us, and at the same time it is representative of the Galactic bulge stellar population: (a) Ortolani et al. (1995) showed that NGC 6553 and NGC 6528 show very similar Colour-Magnitude Diagrams (CMDs), and NGC 6528 is located at d⊙ ≍ 7.83 kpc, very close to the Galactic center; (b) the stellar populations of the Baade Window is also very similar to that of NGC 6553 and NGC 6528 as Ortolani et al. (1995) have shown by comparing their luminosity functions.
Atmosphere models for very low mass stars, brown dwarfs and exoplanets
Authors: Baraffe I. , Allard F.
Published: July 2016

Over the past decade considerable effort, both observational and theoretical, has been directed towards a more accurate determination of the stellar lower main sequence and of the sub-stellar domain covered by Brown Dwarfs and Planets. Astronomers have been looking for brown dwarfs for more than a decade, either with standard astronomical technics or with microlensing experiments. A breakthrough in the search for brown dwarfs was very recently achieved with the discovery of the first cool brown dwarf GL 229B (Nakajima et al. 1995). At the same epoch, the search for planets blossomed with the discovery of a Jupiter - mass companion of the star 51 Pegasi (Mayor and Queloz 199,5). Now, the number of faint, cool stars and substellar objects is rising rapidly.
Parameter identification – a new way of assessing errors in stellar atmosphere analysis
Authors: Wehrse R. , Rosenau Ph.
Published: July 2016

For the consistent and objective determination of stellar parameters and corresponding errors a constrained minimization approach is described which allows to take additional non-spectroscopic information into account and assures that the atmospheric structure equations are always fulfilled.
Bulge δ Scuti stars in the MACHO database
Authors: Minniti D. , Alcock C. , Alves D.R. , Axelrod T.S. , Becker A.C. , Bennett D.R. , Cook K.H. , Freeman K.C. , Griest K. , Lehner M.J. , Marshall S.L. , Peterson B.A. , Quinn P.J. , Pratt M.R. , Rodgers A.W. , Stubbs C.W. , Sutherland W. , Tomaney A. , Vandehei T. , Welch D.
Published: July 2016

We describe the search for δ Scuti stars in the MACHO database of bulge fields. Concentrating on a sample of high amplitude δ Scutis, we examine the light curves and pulsation modes. We also discuss their spatial distribution and evolutionary status using mean colors and absolute magnitudes.
RR Lyrae variables
Authors: Bono G. , Marconi M.
Published: July 2016

On the basis of a historical overview we outline the relevant results which allowed to approach on firm basis the physical mechanisms which govern the radial pulsation of RR Lyrae variables, revealing the astrophysical parameters which account for their limiting amplitude pulsational behavior.
The evolution of massive stars
Authors: Maeder A.
Published: July 2016

Massive stars are the crossroads of many important astrophysical problems and thus a proper understanding of their evolution is very needed. They are the main sources of UV radiation, by heating the interstellar dust they produce the far-IR luminosities of galaxies. They are the precursors of Supernovae and also the main sources of nucleosynthesis. They are visible in distant galaxies and the recent observations of starbursts have shown their major role in the spectral and chemical evolution of galaxies. They begin to be observed in the galactic center and in regions of star formation around galactic nuclei.
The effect of rotation on RGB surface abundances
Authors: Charbonnel C.
Published: July 2016

Pop II field and globular cluster giant stars (and, to a less extent, Pop I giants) exhibit chemical anomalies which are not predicted by standard stellar evolution theory. Two hypotheses have been proposed to explain these abundance variations, namely the primordial and the evolutionary explanations. A primordial origin for intracluster abundance anomalies (see e.g. Cottrel & Da Costa 1981) would be related to inhomogeneities in the cluster material due to pollution by a prior generation of massive stars. In the evolutionary hypothesis, abundance variations would be due to nuclear and mixing processes internal to the giant stars themselves. Many good reviews exist on the subject (see e.g. Briley et al. 1994a, Kraft 1994), in which observational evidence supporting both hypotheses are presented. In this conference, Da Costa recalls the most recent observational data, and some excellent poster contributions bring essential clues to the subject.
Non-variable horizontal-branch stars
Authors: Rood Robert T.
Published: July 2016

For 25 years our ignorance of the physical basis of this mass loss process has been the barrier to progress in understanding horizontal branch morphology. I review some recent observational and theoretical results which may be giving us clues about the nature of the mass loss process.
NLTE analyses of PG 1159 stars: constraints for the structure and evolution of post-AGB stars
Authors: Dreizler S. , Werner K. , Rauch T. , Heber U. , Reid I.N. , Koesterke L.
Published: July 2016

The majority of all stars (Mi < 8M⊙) end their lives as white dwarfs (WD). On the tip of the Asymptotic Giant Branch (AGB) the star ejects its outer layers which become a Planetary Nebula and the stellar core evolves rapidly towards very high effective temperatures (Teff > 100 kK). When the nuclear burning in the H or He shell ceases the star enters the WD cooling sequence. The evolution starting from the AGB is separated in a H–rich and a H–deficient sequence where the latter contributes with a number fraction of ≈ 20%. In this paper we describe our recent effort in the analysis of one group of these stars, the PG 1159 stars.
New model atmosphere analyses of cool white dwarfs: a revised luminosity function and constraints on the age of the Galaxy
Authors: Leggett S.K. , Bergeron P. , Ruiz Maria Teresa
Published: July 2016

We have obtained new photometric and spectroscopic data for a large sample of cool white dwarfs. These data have been analysed with state-of-the-art model atmospheres and effective temperatures and atmospheric compositions have been determined (Bergeron, Ruiz & Leggett 1997). Radii and masses have also been obtained for those stars with accurate parallax measurements. These high quality data and models allow us to produce an improved cool white dwarf luminosity function based on the Liebert, Dahn & Monet (1988) proper motion sample. The turn-over seen at the faint end of this luminosity function, combined with theoretical cooling sequences, enable us to constrain the age of the local region of the Galaxy.
Cosmic Star Formation from the Milky Way and its Satellites
Authors: Hartwick F.D.A.
Published: July 2016

We use observations and evolutionary models of local objects to interpret a recent determination of the star-formation history of the universe. By fitting the global star-formation rate, the model predicts the ratio of spheroid to disk mass of ~1, an intergalactic medium (IGM) whose mass is ~2.3 times the mass in stars, and whose metallicity is ~0.1 Z⊙.
The UM/CTIO Magellanic Cloud Emission-line Survey
Authors: Chris Smith R. ,   the MCELS team
Published: July 2016

The Magellanic Clouds are unique in providing sites to study the interstellar medium (ISM) and its components at all scales. To promote the pursuit of such studies, we have begun the Magellanic Cloud Emission-line Survey (MCELS), a deep imaging survey of both of these nearby galaxies in the emission of Hα, [S II], and [O III]. The emission-line images will be used in detailed optical and multiwavelength studies of H II regions, supernova remnants, planetary nebulae, superbubbles, and supergiant shells. Together with parallel surveys at other wavelengths, this survey will provide the foundation upon which to build a deeper understanding of the ISM in the Clouds and other galaxies, from small scales (~1 pc) all the way up to global scales. We present a sample of recent and current work using the MCELS dataset.
Coronal C+3 in the LMC: Evidence for a Hot Halo
Authors: Wakker Bart
Published: July 2016

Observations of interstellar C IV toward six stars in the Large Magellanic Cloud are described. These data were obtained with the GHRS on HST and with IUE. They provide the first unambiguous evidence that C+3 exists in the Large Magellanic Cloud away from regions where it could have been produced locally, as the six stars are of spectral type later than 08, as well as away from hot early-type stars or active regions. Significant differences between the velocities of the C+3 absorption and those of Hα emission near the stars shows that these ions are not co-spatial, implying that the C+3 originates in the halo of the LMC. It is shown that photo-ionization is unlikely to be the sole source of the C+3 and that the LMC halo thus contains hot gas.
A Digital Emission-Line Survey of the Small Magellanic Cloud
Authors: Winkler P. Frank , Rathore Yasser , Smith R. Chris
Published: July 2016

We present results on the SMC from the first full season of the Michigan/CTIO Magellanic Cloud Emission-Line Survey, being carried out from CTIO. Images are being obtained in Hα, [S II] λλ 6717, 6731, and [O III] λ 5007, plus red and green continuum bands for star subtraction. Data from the 1996–97 season have been assembled into large mosaic images which reveal the rich variety of nebulosity in the SMC in unprecedented detail. These are providing definitive samples of the active, occasionally violent, ISM on scales including superbubbles, wind-blown bubbles, supernova remnants, H II regions, and planetary nebulae.
How to Interpret the Bubble-Dominated ISM in the LMC?
Authors: Palouš Jan , Ehlerová Soňa
Published: July 2016

3D computer simulations are used to discuss shapes, expansion velocties, masses and fragmentation of expanding shells in the LMC.
Molecular Clouds in the LMC Observed with NANTEN: I. Physical Properties of the Clouds
Authors: Mizuno N. , Abe R. , Hara A. , Hayakawa T. , Kato S. , Kawamura A. , Mizuno A. , Ogawa H. , Onishi T. , Saito H. , Tachihara K. , Xiao K. C. , Yamaguchi N. , Yamaguchi R. , Fukui Y. , Yonekura Y.
Published: July 2016

Fully sampled 12CO(J=1−0) observations of the whole extent of the LMC have been made with a linear resolution of ~ 30 pc at a detection limit of N(H2) = 2 × 1021 cm−2. In addition, several selected regions have been mapped with higher sensitivity corresponding to a detection limit of 1 × 1021 cm−2. Based on these results, a new estimate of the molecular mass in the LMC is presented.
Detection of H2 in UV Absorption in the LMC
Authors: Richter P. , de Boer K.S. , Bomans D. J. , Heithausen A. , Koornneef J.
Published: July 2016

Based on measurements with the ORFEUS far UV echelle spectrograph, we present the first detection of H2 in absorption in the Large Magellanic Cloud (LMC) in the spectrum of the star LH 10:3120.
Photodissociation Regions in the Large Magellanic Cloud and IC 10
Authors: Bolatto Alberto D. , Jackson James M. , Wilson Christine D. , Zhang Xiaolei
Published: July 2016

Both theory and observation suggest that metallicity profoundly alters the properties and structure of the Photodissociation Regions (PDRs; e.g., Madden et al. 1997). Several factors contribute to the differences between high and low metallicity systems: altered gas phase and grain surface chemistry due to the low Si, C and S elemental abundances, and diminished dust shielding because of the low dust-to-gas ratio. Since there is less dust shielding, UV photons penetrate more deeply into the molecular clouds leaving H2 unaffected but photodissociating most other molecules everywhere except in the most opaque clumps. Thus, a low-metallicity system contains large regions where hydrogen remains molecular but the usual tracers of molecular gas like CO are photodissociated.
Birth of Supernova Remnant 1987A
Authors: Sonneborn George , Pun C. S. J. , Garnavich Peter , Kirshner Robert
Published: July 2016

Recent observations of SN 1987A made with HST/STIS show that the shock interaction of supernova debris with the innermost edge of the circumstellar ring has begun.
Molecular Clouds in the LMC Observed with NANTEN: II. Comparison with Stellar Clusters
Authors: Yamaguchi R. , Abe R. , Hara A. , Hayakawa T. , Kato S. , Kawamura A. , Mizuno A. , Mizuno N. , Ogawa H. , Onishi T. , Saito H. , Tachihara K. , Xiao K. C. , Yamaguchi N. , Fukui Y. , Yonekura Y.
Published: July 2016

We have made 12CO(J=1−0) observations of the LMC with the NANTEN millimeter-wave telescope and identified about 100 distinct giant molecular clouds (GMCs). A detailed comparison of the GMCs with stellar clusters and a UV image is discussed.
Kinematic Study of the Northwestern Part of the Bar of the LMC
Authors: Ambrocio-Cruz P. , Laval A. , Marcelin M. , Amram P.
Published: July 2016

We have been conducting a Fabry-Perot kinematic survey of ionized gas in the Magellanic Clouds in the Hα and [O III]λ5007 lines, using a 36-cm telescope at the European Southern Observatory. This poster presents our kinematic study of HII regions located at the northwestern parts of the LMC bar.
The Physics of 106 K Gas in LMC Supergiant Shells
Authors: Bomans D. J. , Dennerl K.
Published: July 2016

We present first results of our study of the interplay between the 106 K, 104 K, 102 K gas phases in the supergiant shell LMC 4.
The ISM near SN 1987A: Kinematics and 3-D Structure
Authors: Crotts Arlin P.S. , Xu Jun
Published: July 2016

We present two views of the region around SN 1987A: a three-dimensional map of structure revealed by light echoes, and a multicomponent velocity map at 10 km s−1 resolution in [N II], correlating the various superbubble structures found in both, with implications for their age and dynamics, as well as the history of the SN progenitor.
A Radio-Continuum Study of the Magellanic Clouds
Authors: Filipović M. , Staveley-Smith L. , Haynes R. , White G. , Jones P.
Published: July 2016

We review all radio-continuum surveys of the Magellanic Clouds (MCs) and also present latest results from our new mosaic surveys.
Massive Star Evolution
Authors: Langer N. , Heger A.
Published: July 2016

The evolution of massive stars is far from being fully understood, as we outline by pointing to a number of open problems related to massive stars in the Magellanic Clouds. We argue that rotation may be a key ingredient in the physics of massive stars. We report on recent results obtained including rotation, and their relevance to these remaining questions.
Massive Stars Spectroscopy in the Magellanic Clouds
Authors: Venn K. A.
Published: July 2016

Recent results from spectroscopic studies of Magellanic Cloud stars are discussed. Emphasis is placed on how to interpret CNO abundances to examine stellar evolution scenarios. Observed CNO abundances are best explained by the new rotating stellar evolution models (see Langer & Heger, these proceedings). In addition, the Rolleston et al. (these proceedings) abundances for B stars in the Magellanic Bridge are discussed.
30 Doradus: The Low-Mass Stars
Authors: Zinnecker Hans , Brandl Bernhard , Brandner Wolfgang , Moneti Andrea , Hunter Deidre
Published: July 2016

We present a first analysis of our deep NICMOS/HST F160W images of the 30 Doradus cluster, aimed at detecting the low-mass stellar population (M ≤ 2 M⊙). We find that the infrared luminosity function keeps rising towards the faint end and that there is no indication of a low-mass IMF cut-off down to at least 1.5 M⊙. We also find a change of slope (steepening) in the luminosity function as a function of radial distance from the cluster center. The faintest stars we have detected have H=22.5 mag, corresponding to about M = 0.4 M⊙ at an age of 2 Myr.
30 Doradus as a Nearby Infrared Guide to Starbursts
Authors: Thornley M. D. , Förster Schreiber N.M. , Spoon H.W.W. , Genzel R. , Lutz D. , Kunze D.
Published: July 2016

We are exploring the properties of obscured starburst galaxies, using observations of atomic fine structure lines taken with the Short Wavelength Spectrometer aboard ISO. However, it is important to ascertain how well our starburst models can recover the properties of the stellar populations in more distant starbursts. For this purpose, we use observations of a nebular “shell” in the 30 Doradus region, to show that our models reliably predict the presence of the very massive stars observed directly in the 30 Doradus region.
A High Resolution Optical Summary of the Structure and Dynamics of 30 Doradus
Authors: Scowen P. , Chu Y.-H. , Gruendl R.
Published: July 2016

We present the first comparison between high resolution echelle velocity fields and a mosaic of all Hubble Space Telescope narrowband observations of 30 Doradus.
A New Investigation of the 30 Doradus Region with the Australia Telescope Compact Array
Authors: Lazendic J. S. , Haynes R. F. , Dickel J. R. , Jones P. A. , White G. L. , Costa M.
Published: July 2016

30 Doradus is a giant H II region in the Large Magellanic Cloud (Bode 1801). It is the nearest extragalactic giant H II region and the location of active star formation. The complex nature of this extended region provides an excellent opportunity to investigate the impact of massive stars on the structure of the interstellar medium. Specifically the presence of supernova remnants (SNRs) is expected to play an important role.
The Low End of the Initial Mass Function for the R136 Cluster in the LMC
Authors: Sirianni M. , Nota A. , Leitherer C. , Clampin M. , De Marchi G.
Published: July 2016

Multiple images of the R136 cluster in the Large Magellanic Cloud taken with the HST/WFPC2 and the F555W and F814W filters were combined to obtain very deep images of the cluster, with total exposure times of 1240 and 760 sec respectively. The objective of the study was to extend the luminosity function below the limit of 2.8 M⊙ published by Hunter et al. (1995, 1996).
Interstellar Abundances in the Magellanic Clouds
Authors: Welty D. E. , Frisch P. C. , Hobbs L. M. , York D. G. , Blades J. C. , Lauroesch J. T. , Sonneborn G.
Published: July 2016

We discuss the relative gas-phase abundances found for the predominantly neutral interstellar clouds — located in the Galactic disk and halo, in the LMC or SMC, and (perhaps) in between — along the lines of sight to Sk 108 in the SMC and to SN 1987A in the LMC.
Chemical Abundances and Physical Parameters of H II Regions in the Magellanic Clouds
Authors: Reyes R.E. Carlos
Published: July 2016

I present the results of the photoionization modeling of eleven H II regions in the Magellanic Clouds (MCs). A comparison of their abundances with other systems are also presented.
Star Formation History of the Disk of the Large Magellanic Cloud
Authors: Gallagher J. S. , Cole Andrew A. , Holtzman J. , Smecker-Hane T.
Published: July 2016

New optical observations of field stars in the Large Magellanic Cloud from the ground and with the Hubble Space Telescope provide the basis for investigations of the history of field star formation in our nearest galactic neighbor. Results from WFPC2 photometry of field stars indicate that the stellar initial mass function for stars around 1 M⊙ is similar to that in the solar neighborhood. Long-term variations occurred in the average SFR with enhanced activity in the past 2–4 Gyr, a fallow period about 2–10 Gyr in the past, and an initial phase of astration ~12 Gyr ago. The recent increase in field star formation is less than that for the birth of compact star clusters; the cluster formation rate does not give a complete evolutionary picture.
Results from the EROS Microlensing Survey
Authors: Beaulieu J. P. , Lamers H.J.G.L.M. , de Wit W.J.
Published: July 2016

We present a status report of the original EROS and the on-going EROS-2 microlensing surveys, which were created to search for dark matter in the Galactic halo via microlensing effects on LMC/SMC stars. Microlensing surveys provide long-term systematic observations of millions of stars in both Clouds which yield a unique database of stellar photometry and variability. We review the results obtained on pulsating stars and detail the similarities and differences of the Magellanic Cloud Herbig Ae/Be stars with their Galactic counterparts.
Isochrone Probability Functions for Old Stellar Systems
Authors: Bergbusch Peter A.
Published: July 2016

The isochrone probability function (IPF) is derived from the slope of the mass–distance relation on an isochrone in where the distance along the isochrone is computed with respect to some arbitrary, well-defined point. IPFs contain the information needed to calculate both luminosity functions and color functions, and they provide a straightforward way of generating synthetic stellar populations.
The Star Formation History of the Magellanic Clouds: A Preliminary Report
Authors: Harris Jason , Zaritsky Dennis , Grebel Eva K. , Thompson Ian
Published: July 2016

We present a method to determine the star formation history (SFH) of a mixed stellar population, based on an iterative maximum Likelihood comparison of stellar photometry to model color-magnitude diagrams. We demonstrate the algorithm on a subregion of the Large Magellanic Cloud, observed as part of our ongoing Magellanic Clouds Photometric Survey. We will eventually perform this analysis on hundreds of regions in both Clouds, resulting in a homogeneous SFH map of these galaxies.
Peculiarities of the Stellar Population of Bars in the LMC and Other Barred Galaxies
Authors: Gusev A. S.
Published: July 2016

The age distributions in the bar and disk of the Large Magellanic Cloud are studied using data for 262 clusters with known ages, of which 89 are located in the bar. The spatial distributions for clusters in different age groups are investigated. Epochs of active star formation are determined for the bar and disk of the LMC. The ages of the stellar populations in the bar differ from that for the galaxy as a whole: in the bar, there is a deficit of intermediate-age clusters (5 × 108–6 × 109 yr) and an excess of young clusters with ages 3 × 107–5 × 108 yr. This indicates that the star formation history in the bar differs from that in regions outside the bar at the same distances from the center of the galaxy. Data on the composition of the old stellar populations in the bar and the disk of the LMC and the spatial distribution of intermediate-age clusters in the galaxy suggest that the LMC bar formed (2–6) × 109 years ago. Deviation of colors of bars from the normal color sequence of galaxies on several two-color diagrams is found using multicolor surface photometry for eight barred galaxies. Using results of evolutionary synthesis modeling, I can model the abnormal colors of bars by an intermediate-age star (~ 109 yr) deficiency. I find that the deficiency of an intermediate-age stellar population is a general property of bars.
HST FOC and Broad Band Colors for Young and Intermediate Simple Stellar Populations
Authors: Brocato E. , Castellani V. , Raimondo G. , Romaniello M.
Published: July 2016

We present theoretical HST and broad band colors from young and intermediate stellar populations with age ranging from t = 8 Myr to t = 5 Gyr and three different metallicities Z=0.02, 0.006 and 0.001. We suggest the combined use of HST UV colors and IR colors (V-K in particular) to disentangle the metallicity-age effect in integrated colors of young stellar populations (t ≤ 1 Gyr).
Pre-main-sequence Stars in the SMC and LMC
Authors: Brandner Wolfgang , Grebel Eva K. , Zinnecker Hans , Brandl Bernhard
Published: July 2016

We present first results of a survey for pre-main-sequence stars in the Magellanic Clouds. Our search concentrated on NGC 346, the most prominent OB association in the Small Magellanic Cloud, and on the 30 Dor starburst cluster in the Large Magellanic Cloud. The identification of the young low- to intermediate-mass stellar population in the SMC and LMC allows us to study whether or not these populations formed simultaneously with high-mass stars, and to what an extent lower metallicity affects the low-mass IMF. We can also evaluate the duration of star formation in a starburst region.
Radiation-Pressure Ejection of Planetary Nebulae in Asymptotic-Giant-Branch Stars
Authors: Sweigart A. V.
Published: July 2016

We have investigated the possibility that radiation pressure might trigger planetary nebula (PN) ejection during helium-shell flashes in asymptotic-giant-branch (AGB) stars. We find that the outward flux at the base of the hydrogen envelope during a flash will reach the Eddington limit when the envelope mass Menv falls below a critical value that depends on the core mass MH and composition. These results may help to explain the helium-burning PN nuclei found in the Magellanic Clouds.
Red Giant Stars in Magellanic Cloud Clusters: Constraining Population Synthesis Models
Authors: Girardi Léo
Published: July 2016

We have developed a population synthesis code, aimed mainly at the interpretation of CMDs. Magellanic Cloud clusters have been largely used for the test/calibration of the underlying stellar tracks.
ISO Observations of Compact HII Regions in the Large Magellanic Cloud
Authors: Moneti A. , Laureijs R. J. , van der Hulst J.M. , Israel F. , van der Werf P.P.
Published: July 2016

With the detection of strong PAH features and H2 emission in selected knots of the N159, N11A, and 30 Dor regions in the LMC, we present the first results of a study that is part of a coordinated Guaranteed Time ISO programme to investigate star formation in the Magellanic Clouds. The PAH features have different ratios than the ones in Galactic reflection nebulae.
Ages and Metallicities of LMC Clusters and Their Surrounding Fields
Authors: Geisler Doug , Bica Eduardo , Dottori Horacio , Clariá Juan J. , Piatti Andrés E. , Santos João F.C.
Published: July 2016

We report on a survey of 25 candidate old LMC clusters. Washington photometry was obtained on the CTIO 0.9m in < 1h, reaching below the turnoff. Ages based on the magnitude difference δT1 between the giant branch clump and the turnoff revealed that no new old clusters were found. The candidates all turned out to be of intermediate age (1–3 Gyr). We confirm that there was apparently no cluster formation in the LMC from 3–9 Gyr ago, and that there was a pronounced epoch of cluster formation beginning 3 Gyrs ago that peaked at ~1.5 Gyrs ago. We also determine ages for the surrounding fields, as well as metallicities for both the clusters and fields from the color of the giant branch. In most cases the stellar population of each cluster is quite similar to that of its field. The mean metallicity for the intermediate age outer disk clusters is −0.65. A few clusters stand out in the age-metallicity relation in the sense that they are intermediate age clusters at relatively low metallicity. In the northern part of the LMC disk 3 fields all have a secondary clump ~0.45 mag fainter than the dominant clump, suggesting a component located behind the LMC at a distance comparable to that of the SMC.
Star Cluster Encounters in the Magellanic Clouds
Authors: de Oliveria M.R. , Dottori H. , Bica E.
Published: July 2016

The study of star cluster pairs in the Magellanic Clouds (MCs) has been explored extensively in the past years (Bhatia & Hatzidimitriou 1988; Rodrigues et al. 1994; de Oliveira et al. 1998). The evolution of these pairs can provide fundamental insight into the past history of cluster formation in the MCs.

We have selected MC clusters (Bica & Schmitt 1995; Bica et al. 1998) with morphologies resembling those of the present models. The images in this selection of pairs were obtained from the Digital Sky Survey (DSS). We have also performed N-body simulations of star cluster encounters under different initial conditions, with the total number of particles per simulation ranging from 1024 to 20480.
The Recent Star Formation History of the LMC Southwest Quadrant
Authors: Battinelli Paolo , Demers Serge
Published: July 2016

Recently, Demers & Battinelli (1998) have shown that the young intercloud stellar aggregates are 10 to 25 Myr old, thus younger than the estimated age (200 Myr) of the last close LMC–SMC encounter (see, e.g., Irwin et al. 1996). These stellar aggregates show a distance gradient that confirms the existence of a “link” between the two Magellanic Clouds. Numerous blue stars have been detected by Demers & Irwin (1991) east of the aggregate ICA76 (the closest to the LMC). These blue stars, that extend to the southwestern periphery of the LMC, may be an aftermath of the close LMC–SMC encounter. Our present study is aimed to survey this SW part of the LMC and to determine the origin of these blue stars.
The Aftermaths of the SMC/LMC Encounter
Authors: Demers Serge , Kunkel W. E.
Published: July 2016

We present structural and kinematic evidence pointing to a gravitational interaction between the two Magellanic Clouds. We discuss, in particular, the results of our kinematic survey of carbon stars in the periphery of the LMC. Stars with peculiar velocities, in the LMC southwest, are identified as part of debris left on the SMC orbit around the LMC.
The Magellanic Cloud Interaction: Interpretation and Constraints from Observations of Carbon Stars as “Test Particles”
Authors: Kunkel William , Demers Serge
Published: July 2016

Since gravity alone acts on them, and their evolutionary age restricts sampling to “mid-life”, carbon stars are examined as tracers of recent dynamical evolution of the Magellanic Clouds. Ablation processes modify the distribution of HI, and velocity outliers reflect recent tidal interactios.