scholarly journals Improved modelling for spatially resolved spectroscopy of a P Cyg envelope

1994 ◽  
Vol 162 ◽  
pp. 502-504
Author(s):  
M. Bourguine ◽  
A. Chalabaev
Keyword(s):  
Angular Resolution ◽  
Theoretical Models ◽  
Progress Report ◽  
High Angular Resolution ◽  
Physical Parameters ◽  
Base Length ◽  
Spatially Resolved ◽  
Wide Range ◽  
Spatially Resolved Spectroscopy ◽  
Stellar Envelopes

Our study, of which we give here a progress report, addresses two problems. The first is to develop methods and software permitting to compare a wide range of theoretical models of stars with envelopes with observational data produced or expected to be produced by high angular resolution optical interferometry combined with spectroscopy. The second problem is to find out the modes of interferometric observations (base length, spectral resolution etc) that are most informative for determining the physical parameters of stellar envelopes.

scholarly journals Chandra and XMM Observations of Galaxy Groups: The Influence of Central AGN at the Low End of the Cluster Mass Scale

2006 ◽  
Vol 2 (S235) ◽  
pp. 255-255
Author(s):  
J. M. Vrtilek ◽  
E. J. O'Sullivan ◽  
L. P. David
Keyword(s):  
Angular Resolution ◽  
Mass Scale ◽  
Heavy Elements ◽  
High Angular Resolution ◽  
Galaxy Interactions ◽  
X Ray ◽  
Galaxy Groups ◽  
Spatially Resolved ◽  
Formation And Evolution ◽  
Spatially Resolved Spectroscopy

AbstractChandra and XMM, offering between them high angular resolution, substantial collecting area, and spatially-resolved spectroscopy at good spectral resolution, have given us the means to discover hitherto unanticipated phenomena, in groups as in clusters, and to explore a new set of issues that bring us closer to understanding the formation and evolution of groups and their constituent galaxies: the distribution of heavy elements, the presence of X-ray cavities and their relation to radio observations, the nature of cooling cores, and X-ray signatures of recent galaxy interactions. We here show Chandra and XMM data selected to illustrate recent results regarding some of these themes.

scholarly journals High gas-to-dust size ratio indicating efficient radial drift in the mm-faint CX Tauri disk

2019 ◽  
Vol 626 ◽  
pp. L2 ◽  
Author(s):  
S. Facchini ◽  
E. F. van Dishoeck ◽  
C. F. Manara ◽  
M. Tazzari ◽  
L. Maud ◽  
...  
Keyword(s):  
Near Infrared ◽  
Angular Resolution ◽  
Spectral Energy Distribution ◽  
Theoretical Models ◽  
Intensity Profile ◽  
Continuum Emission ◽  
Spectral Energy ◽  
High Angular Resolution ◽  
Sharp Drop ◽  
Large Program

The large majority of protoplanetary disks have very compact continuum emission (≲15 AU) at millimeter wavelengths. However, high angular resolution observations that resolve these small disks are still lacking, due to their intrinsically fainter emission compared with large bright disks. In this Letter we present 1.3 mm ALMA data of the faint disk (∼10 mJy) orbiting the TTauri star CX Tau at a resolution of ∼40 mas, ∼5 AU in diameter. The millimeter dust disk is compact, with a 68% enclosing flux radius of 14 AU, and the intensity profile exhibits a sharp drop between 10 and 20 AU, and a shallow tail between 20 and 40 AU. No clear signatures of substructure in the dust continuum are observed, down to the same sensitivity level of the DSHARP large program. However, the angular resolution does not allow us to detect substructures on the scale of the disk aspect ratio in the inner regions. The radial intensity profile closely resembles the inner regions of more extended disks imaged at the same resolution in DSHARP, but with no rings present in the outer disk. No inner cavity is detected, even though the disk has been classified as a transition disk from the spectral energy distribution in the near-infrared. The emission of 12CO is much more extended, with a 68% enclosing flux radius of 75 AU. The large difference of the millimeter dust and gas extents (> 5) strongly points to radial drift, and closely matches the predictions of theoretical models.

scholarly journals Herbig Ae/Be Star Disks at High Angular Resolution

2004 ◽  
Vol 221 ◽  
pp. 389-394
Author(s):  
C. P. Dullemond ◽  
C. Dominik ◽  
R. van Boekel ◽  
R. Waters ◽  
M. van den Ancker
Keyword(s):  
Angular Resolution ◽  
Protoplanetary Disks ◽  
Spectral Energy ◽  
High Angular Resolution ◽  
Be Stars ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Spatially Resolved ◽  
Be Star ◽  
Geometric Picture

We show that there exists a simple geometric picture for the geometries of protoplanetary disks around Herbig Ae/Be stars that explains the two main kinds of spectral energy distributions found for these objects, and that makes predictions that are qualitatively in agreement with currently available spatially resolved images and/or interferometric measurements. Also it qualitatively explains the phenomenon of UX Orionis variability.

scholarly journals ISM / Radio Material Interaction Modeling

1996 ◽  
Vol 175 ◽  
pp. 465-466
Author(s):  
P. Ferruit ◽  
L. Binette ◽  
E. Pecontal
Keyword(s):  
Good Description ◽  
Theoretical Models ◽  
High Angular Resolution ◽  
Atomic Physic ◽  
Dynamical Models ◽  
Full Account ◽  
Spatially Resolved ◽  
Interaction Modeling ◽  
Resolution Imaging ◽  
Material Interaction

With the outcoming of high angular resolution imaging and 3D spectrographic facilities (HST, TIGER-OASIS at the CFH Telescope…), the need of spatially resolved theoretical models of the kinematic interaction of radio material with the ISM (or the IGM for radio-galaxies) is increasing dramatically. In order to fill the gap between pure hydro dynamical models (3D approach, but very poor atomic physic) and photoionisation/shocks ones (planar description, full account for atomic physic processes), we have started to develop 2D or 3D hydro dynamical models including a good description of atomic physic processes (using photoionisation routines from the code MAPPINGS).

scholarly journals Introduction to the Joint Commission Meeting on High Resolution Imaging from the Ground

1989 ◽  
Vol 8 ◽  
pp. 545-546
Author(s):  
John Davis
Keyword(s):  
High Resolution ◽  
Angular Resolution ◽  
High Angular Resolution ◽  
High Resolution Imaging ◽  
Wide Range ◽  
High Resolution Images ◽  
Resolution Imaging ◽  
Optical Wavelengths ◽  
To Come ◽  
Very High

As a result of advances in instrumentation and techniques, from radio through to optical wavelengths, we have before us the prospect of producing very high resolution images of a wide range of objects across this entire spectral range. This prospect, and the new knowledge and discoveries that may be anticipated from it, lie behind an upsurge in interest in high resolution imaging from the ground. Several new high angular resolution instruments for radio, infrared, and optical wavelengths are expected to come into operation before the 1991 IAU General Assembly.

scholarly journals Radio Continuum Observations of Large Supernova Remnants

1983 ◽  
Vol 101 ◽  
pp. 377-379
Author(s):  
W. Reich ◽  
E. Fürst ◽  
W. Sieber
Keyword(s):  
Supernova Remnants ◽  
Angular Resolution ◽  
Field Structure ◽  
Radio Continuum ◽  
High Angular Resolution ◽  
Physical Parameters ◽  
Field Orientation ◽  
Low Frequencies ◽  
Magnetic Field Orientation ◽  
Polarization Characteristics

Radio observations of large supernova remnants (SNRs) with high angular resolution have been provided by modern synthesis instruments preferentially at frequencies below 2 GHz. Since these instruments are sensitive mainly to unresolved emission spots, weak extended SNRs usually remain undetected. Besides this, there are numerous physical parameters, which can be studied more properly at higher frequencies. In particular, the polarization characteristics can be more easily analyzed and reduced to the intrinsic magnetic field orientation. In some cases foreground effects substantially disturb the SNR's field structure at low frequencies.

A New Very High Angular Resolution Stellar Interferometer

1985 ◽  
Vol 6 (1) ◽  
pp. 38-43 ◽  
Author(s):  
J . Davis ◽  
W . J . Tango
Keyword(s):  
Angular Resolution ◽  
High Angular Resolution ◽  
Stellar Interferometer ◽  
Wide Range ◽  
New Instrument ◽  
The University ◽  
Very High

AbstractThe Chatterton Astronomy Department of the University of Sydney is proposing the construction of a very high angular resolution stellar interferometer of major astronomical and international significance. Based on the prototype modern Michelson stellar interferometer which the Department has developed, the new instrument will be used in a wide range of astrophysical programmes. The siting, specification, design and costing of the instrument are outlined.

scholarly journals A CO-multilayer outer atmosphere for eight evolved stars revealed with VLTI/AMBER

2019 ◽  
Vol 489 (2) ◽  
pp. 2595-2614
Author(s):  
M Hadjara ◽  
P Cruzalèbes ◽  
C Nitschelm ◽  
X Chen ◽  
E A Michael ◽  
...  
Keyword(s):  
Angular Resolution ◽  
High Angular Resolution ◽  
Physical Parameters ◽  
Fine Grid ◽  
Stellar Radius ◽  
Evolved Stars ◽  
Very Large Telescope ◽  
Outer Atmosphere ◽  
Red Giant ◽  
The Individual

Abstract We determine the physical parameters of the outer atmosphere of a sample of eight evolved stars, including the red supergiant α Scorpii, the red giant branch stars α Bootis and γ Crucis, the K giant λ Velorum, the normal M giants BK Virginis and SW Virginis, and the Mira star W Hydrae (in two different luminosity phases) by spatially resolving the stars in the individual carbon monoxide (CO) first overtone lines. We used the Astronomical Multi-BEam combineR (AMBER) instrument at the Very Large Telescope Interferometer (VLTI), in high-resolution mode (λ/Δλ ≈ 12 000) between 2.28 and 2.31 $\, \mu {\rm m}$ in the K band. The maximal angular resolution is 10 mas, obtained using a triplet telescope configuration, with baselines from 7 to 48 m. By using a numerical model of a molecular atmosphere in a spherical shells (MOLsphere), called pampero (an acronym for the ‘physical approach of molecular photospheric ejection at high angular resolution for evolved stars’), we add multiple extended CO layers above the photospheric marcs model at an adequate spatial resolution. We use the differential visibilities and the spectrum to estimate the size (R) of the CO molsphere, its column density (NCO) and temperature (Tmol) distributions along the stellar radius. The combining of the χ2 minimization and a fine grid approach for uncertainty analysis leads to reasonable NCO and Tmol distributions along the stellar radius of the MOLsphere.

Slumped glass optics with interfacing ribs for high angular resolution x-ray astronomy: a progress report

2015 ◽  
Author(s):  
M. Civitani ◽  
S. Basso ◽  
C. Brizzolari ◽  
M. Ghigo ◽  
G. Pareschi ◽  
...  
Keyword(s):  
Angular Resolution ◽  
Progress Report ◽  
High Angular Resolution ◽  
X Ray ◽  
Glass Optics

scholarly journals Active gas features in three HSC-SSP CAMIRA clusters revealed by high angular resolution analysis of MUSTANG-2 SZE and XXL X-ray observations

2020 ◽  
Vol 501 (2) ◽  
pp. 1701-1732
Author(s):  
Nobuhiro Okabe ◽  
Simon Dicker ◽  
Dominique Eckert ◽  
Tony Mroczkowski ◽  
Fabio Gastaldello ◽  
...  
Keyword(s):  
Large Scale ◽  
Angular Resolution ◽  
Major Axis ◽  
High Angular Resolution ◽  
X Ray ◽  
Spatially Resolved ◽  
Sunyaev Zel'dovich Effect ◽  
Major Merger ◽  
Resolution Analysis ◽  
A Minor

ABSTRACT We present results from simultaneous modelling of high angular resolution GBT/MUSTANG-2 90 GHz Sunyaev–Zel’dovich effect (SZE) measurements and XMM-XXL X-ray images of three rich galaxy clusters selected from the HSC-SSP Survey. The combination of high angular resolution SZE and X-ray imaging enables a spatially resolved multicomponent analysis, which is crucial to understand complex distributions of cluster gas properties. The targeted clusters have similar optical richnesses and redshifts, but exhibit different dynamical states in their member galaxy distributions: a single-peaked cluster, a double-peaked cluster, and a cluster belonging to a supercluster. A large-scale residual pattern in both regular Compton-parameter y and X-ray surface brightness distributions is found in the single-peaked cluster, indicating a sloshing mode. The double-peaked cluster shows an X-ray remnant cool core between two SZE peaks associated with galaxy concentrations. The temperatures of the two peaks reach ∼20–30 keV in contrast to the cool core component of ∼2 keV, indicating a violent merger. The main SZE signal for the supercluster is elongated along a direction perpendicular to the major axis of the X-ray core, suggesting a minor merger before core passage. The SX and y distributions are thus perturbed at some level, regardless of the optical properties. We find that the integrated Compton y parameter and the temperature for the major merger are boosted from those expected by the weak-lensing mass and those for the other two clusters show no significant deviations, which is consistent with predictions of numerical simulations.

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