Variation in the near-infrared surface brightness distribution of the bipolar nebula OH 231.8 + 4.2

1992 ◽  
Vol 398 ◽  
pp. 552 ◽  
Author(s):  
Joel H. Kastner ◽  
David A. Weintraub ◽  
B. Zuckerman ◽  
E. E. Becklin ◽  
I. McLean ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Near Infrared ◽  
Brightness Distribution

scholarly journals A dichotomy between HSB and LSB galaxies

1999 ◽  
Vol 171 ◽  
pp. 92-101
Author(s):  
Marc Verheijen ◽  
Brent Tully
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Luminosity Function ◽  
Near Infrared ◽  
Brightness Distribution ◽  
Dark Matter Mass ◽  
Total Luminosity ◽  
Major Cluster ◽  
Baryonic Mass ◽  
Lsb Galaxies

AbstractA complete sample of spiral galaxies in the Ursa Major cluster is imaged at various optical wavelengths and in the Near-Infrared K′-band. HI rotation curves were obtained for all gas rich systems. The Near-Infrared surface brightness distribution of disk galaxies turns out to be bimodal; galaxies avoid a domain around mag/arcsec2. This bimodality is particularly striking when only the more isolated, non-interacting systems are considered. The Luminosity Function of the HSB family of galaxies is truncated well above the completion limit while the Luminosity Function of the LSB family is still sharply rising at our limiting magnitude. Near-Infrared mass-to-light ratios suggest that HSB galaxies are close to a kinematic maximum-disk situation while LSB galaxies are dark matter dominated at all radii. Assuming equal Near-Infrared mass-to-light ratios for both HSB and LSB systems, we find that the gap in the surface brightness distribution corresponds to a situation in which the baryonic mass is marginally self-gravitating. We finally conclude that the luminosity-line width relation is a fundamental correlation between the amount and distribution of dark matter mass and the total luminosity, regardless of how the luminous mass is distributed within the dark mater halo.

scholarly journals Galaxy disc central surface brightness distribution in the optical and near-infrared bands

2019 ◽  
Vol 484 (2) ◽  
pp. 1549-1562
Author(s):  
L Zhou ◽  
W Du ◽  
H Wu ◽  
Y C Liang ◽  
M He ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Near Infrared ◽  
Brightness Distribution ◽  
Central Surface

scholarly journals The Near-Infrared Surface Brightness Distribution of NGC 4696

2006 ◽  
Vol 23 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Pablo Arnalte Mur ◽  
Simon C. Ellis ◽  
Matthew Colless
Keyword(s):  
Free Parameter ◽  
Surface Brightness ◽  
Near Infrared ◽  
Elliptical Galaxy ◽  
Brightness Distribution ◽  
Effective Radius ◽  
Two Dimensional ◽  
Cluster Of Galaxies ◽  
Sky Survey ◽  
Fitting Algorithm

AbstractWe present H-band observations of the elliptical galaxy NGC 4696, the brightest member of the Centaurus cluster of galaxies. We have measured its light profile, using a two-dimensional fitting algorithm, out to a radius of 180 arcsec (37 h70−1 kpc). The profile is well described by a de Vaucouleurs law, with an effective radius of 35.3 ± 1.0 h70−1 kpc. There is no need for the extra free parameter allowed by a Sérsic law. Allowing for a variation of 0.3% in the sky level, the profile obtained is compatible with data from the Two-Micron All Sky Survey (2MASS). The profile shows no sign of either a truncation or an extended halo.

scholarly journals Near-infrared surface brightness fluctuations and optical colours of Magellanic star clusters

2005 ◽  
Vol 363 (4) ◽  
pp. 1279-1289 ◽  
Author(s):  
R. A. González-Lópezlira ◽  
M. Y. Albarrán ◽  
M. Mouhcine ◽  
M. C. Liu ◽  
G. Bruzual-A. ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Near Infrared ◽  
Star Clusters ◽  
Surface Brightness Fluctuations

scholarly journals When Darwin Met Einstein: Gravitational Lens Inversion with Genetic Algorithms

2005 ◽  
Vol 22 (2) ◽  
pp. 128-135 ◽  
Author(s):  
Brendon J. Brewer ◽  
Geraint F. Lewis
Keyword(s):  
Genetic Algorithms ◽  
Gravitational Lensing ◽  
Surface Brightness ◽  
Initial Study ◽  
Brightness Distribution ◽  
Gravitational Lens ◽  
Atmospheric Effects ◽  
Lens Model ◽  
New Approach ◽  
Genetic Algorithm Approach

AbstractGravitational lensing can magnify a distant source, revealing structural detail which is normally unresolvable. Recovering this detail through an inversion of the influence of gravitational lensing, however, requires optimisation of not only lens parameters, but also of the surface brightness distribution of the source. This paper outlines a new approach to this inversion, utilising genetic algorithms to reconstruct the source profile. In this initial study, the effects of image degradation due to instrumental and atmospheric effects are neglected and it is assumed that the lens model is accurately known, but the genetic algorithm approach can be incorporated into more general optimisation techniques, allowing the optimisation of both the parameters for a lensing model and the surface brightness of the source.

scholarly journals CO line and radio continuum study of elephant trunks: the Pillars of Creation in M16

2020 ◽  
Vol 492 (4) ◽  
pp. 5966-5979 ◽  
Author(s):  
Yoshiaki Sofue
Keyword(s):  
Surface Brightness ◽  
Galactic Plane ◽  
Brightness Distribution ◽  
Radio Continuum ◽  
Very Large Array ◽  
Heating Source ◽  
Velocity Gradients ◽  
Magnetic Oscillation ◽  
H Ii Region ◽  
Line Survey

ABSTRACT Molecular line and radio continuum properties of the elephant trunks (ET, Pillars of Creation) in M16 are investigated by analysing 12CO(J = 1−0) , 13CO(J = 1−0) and C18O(J = 1−0) line survey data from the Nobeyama 45-m telescope and the Galactic plane radio survey at 20 and 90 cm with the Very Large Array. The head clump of Pillar West I is found to be the brightest radio source in M16, showing a thermal spectrum and the properties of a compact H ii region, with the nearest O5 star in NGC 6611 being the heating source. The radio pillars have a cometary structure concave to the molecular trunk head, and the surface brightness distribution obeys a simple illumination law from a remote excitation source. The molecular density in the pillar head is estimated to be several 104 H2 cm−3 and the molecular mass is $\sim 13\!-\!40 \, \mathrm{M}_\odot$. CO-line kinematics reveals random rotation of the clumps in the pillar tail at ∼1–2 km s−1, comparable with the velocity dispersion and estimated Alfvén velocity. It is suggested that the random directions of the velocity gradients would manifest as torsional magnetic oscillation of the clumps around the pillar axis.

scholarly journals The mergers in Abell 2256: displaced gas and its connection to the radio-emitting plasma

2020 ◽  
Vol 495 (4) ◽  
pp. 5014-5026 ◽  
Author(s):  
J P Breuer ◽  
N Werner ◽  
F Mernier ◽  
T Mroczkowski ◽  
A Simionescu ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Large Scale ◽  
Cold Front ◽  
Low Frequency ◽  
Brightness Distribution ◽  
Analytical Models ◽  
Line Of Sight ◽  
Cluster Galaxy ◽  
X Ray ◽  
Low Entropy

ABSTRACT We present the results of deep Chandra and XMM–Newton X-ray imaging and spatially resolved spectroscopy of Abell 2256, a nearby (z = 0.058) galaxy cluster experiencing multiple mergers and displaying a rich radio morphology dominated by a large relic. The X-ray data reveal three subclusters: (i) the ‘main cluster’; (ii) the remnant of an older merger in the east of the cluster with an ∼600 kpc-long tail; (iii) a bright, bullet-like, low-entropy infalling system, with a large line-of-sight velocity component. The low-entropy system displays a 250 kpc-long cold front with a break and an intriguing surface brightness decrement. Interestingly, the infalling gas is not co-spatial with bright galaxies and the radio-loud brightest cluster galaxy of the infalling group appears dissociated from the low-entropy plasma by ∼50 kpc in projection, to the south of the eastern edge of the cold front. Assuming that the dark matter follows the galaxy distribution, we predict that it is also significantly offset from the low-entropy gas. Part of the low-frequency radio emission near the cold front might be revived by magnetic field amplification due to differential gas motions. Using analytical models and numerical simulations, we investigate the possibility that the supersonic infall of the subcluster generates a large-scale shock along our line of sight, which can be detected in the X-ray temperature map but is not associated with any clear features in the surface brightness distribution.

scholarly journals Cepheid distances from the Baade–Wesselink method

2012 ◽  
Vol 8 (S289) ◽  
pp. 138-144 ◽  
Author(s):  
Wolfgang Gieren ◽  
Jesper Storm ◽  
Nicolas Nardetto ◽  
Alexandre Gallenne ◽  
Grzegorz Pietrzyński ◽  
...  
Keyword(s):  
Excellent Agreement ◽  
Surface Brightness ◽  
Recent Progress ◽  
Main Sequence ◽  
Near Infrared ◽  
Open Cluster ◽  
Open Clusters ◽  
Distance Scale ◽  
Systematic Uncertainties ◽  
Classical Cepheids

AbstractRecent progress on Baade–Wesselink (BW)-type techniques to determine the distances to classical Cepheids is reviewed. Particular emphasis is placed on the near-infrared surface-brightness (IRSB) version of the BW method. Its most recent calibration is described and shown to be capable of yielding individual Cepheid distances accurate to 6%, including systematic uncertainties. Cepheid distances from the IRSB method are compared to those determined from open cluster zero-age main-sequence fitting for Cepheids located in Galactic open clusters, yielding excellent agreement between the IRSB and cluster Cepheid distance scales. Results for the Cepheid period–luminosity (PL) relation in near-infrared and optical bands based on IRSB distances and the question of the universality of the Cepheid PL relation are discussed. Results from other implementations of the BW method are compared to the IRSB distance scale and possible reasons for discrepancies are identified.

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