scholarly journals A new model for the infrared brightness of the Galaxy

2000 ◽  
Vol 313 (2) ◽  
pp. 263-270 ◽  
Author(s):  
J. R. D. Lepine ◽  
P. Leroy
Keyword(s):  
New Model ◽  
The Galaxy ◽  
Infrared Brightness

scholarly journals The Case for no field decay from improved pulsar population studies

1996 ◽  
Vol 160 ◽  
pp. 47-48
Author(s):  
J.W. Hartman ◽  
F. Verbunt ◽  
D. Bhattacharya ◽  
R. Wijers
Keyword(s):  
Population Studies ◽  
Solar Neighborhood ◽  
Radio Pulsar ◽  
Population Synthesis ◽  
Radio Pulsars ◽  
Free Electrons ◽  
New Model ◽  
Full Report ◽  
The Galaxy ◽  
Field Decay

We perform radio pulsar population synthesis to study the evolution of the pulsar population. In doing this, we continue our earlier work on this subject (Bhattacharya et al. 1992). We have extended our work by 1) calculating orbits in the whole galaxy (the simulation of the observations however is still limited to the solar neighborhood), 2) using the high birth velocities of radio pulsars from Lyne & Lorimer (1994) and 3) implementing the new model by Taylor & Cordes (1993) of the distribution of free electrons in the galaxy. A full report of this work will be given in Hartman et al. (1996).

A New Model for the Spiral Structure of the Galaxy: Superposition of 2‐ and 4‐armed Patterns

2001 ◽  
Vol 546 (1) ◽  
pp. 234-247 ◽  
Author(s):  
J. R. D. Lepine ◽  
Yu. N. Mishurov ◽  
S. Yu. Dedikov
Keyword(s):  
Spiral Structure ◽  
New Model ◽  
The Galaxy

scholarly journals New X-shaped bulge photometric model as a tool for measuring B/PS bulges and their X-structures in photometric studies

2020 ◽  
Vol 499 (1) ◽  
pp. 462-481
Author(s):  
Anton A Smirnov ◽  
Sergey S Savchenko
Keyword(s):  
Half Plane ◽  
Numerical Models ◽  
Spectral Characteristics ◽  
Analytical Models ◽  
Structure Parameters ◽  
New Model ◽  
Self Consistent ◽  
The Galaxy ◽  
Galaxy Model ◽  
Upper Half Plane

ABSTRACT Recent orbital studies of 3D bar structure in various numerical and analytical models show that X-structures that reside in boxy/peanut-shaped (B/PS) bulges are not delineated by some specific type of orbits, but are natural parts of them and formed by the same orbits that constitute such bulges. This implies that to accurately account for B/PS bulges and their X-structures in photometric studies, one needs the photometric model of B/PS bulge that includes an X-structure as its natural part. To find such a model, we considered a self-consistent numerical galaxy model where a typical B/PS bulge arises. Using spectral characteristics of particle-‘stars’, we decomposed the galaxy model on to the bar and non-bar components. We used the extracted 3D bar component to find an appropriate B/PS bulge photometric model, which can account for X-structures residing in such bulges. The resulted B/PS bulge photometric model has a truncated 2D Sersic profile with truncations introduced above (in the upper half-plane) and below (in the bottom half-plane) the rays of X-structures. We applied this model to represent B/PS bulges of various numerical models and some real galaxies. The comparison with previous works revealed that there are systematic shifts between the X-structure parameters of the same galaxies measured within the different approaches. We found that the geometric parameters of X-structures of real and modelled galaxies are consistent with each other if we measure them using our new model.

scholarly journals Observations of the near infrared survace brightness distribution of the galaxy

1979 ◽  
Vol 84 ◽  
pp. 377-380 ◽  
Author(s):  
H. Okuda ◽  
T. Maihara ◽  
N. Oda ◽  
T. Sugiyama
Keyword(s):  
Central Region ◽  
Near Infrared ◽  
Interstellar Extinction ◽  
Brightness Distribution ◽  
The Galaxy ◽  
Infrared Wavelengths ◽  
Optical Wavelengths ◽  
Inner Region ◽  
Infrared Brightness

Studies of the stellar distribution in the inner region of our Galaxy have been seriously hampered at optical wavelengths by strong interstellar extinction. The extinction decreases considerably at infrared wavelengths, allowing us to look deep into the Galaxy. Motivated by this, we have tried to observe the near infrared brightness distribution of the central region of the Galaxy (Okuda et al., 1977, Maihara et al., 1978, Oda et al., 1978). Similar observations have been carried out by Hayakawa et al., (1976), Ito et al., (1977), and Hofmann et al., (1977). These observations have provided valuable information on the distributions of stars and dust in the inner Galaxy (Hayakawa et al., 1977, Maihara et al., 1978, Oda et al., 1978).

scholarly journals Mass extinction and the structure of the milky way

2013 ◽  
pp. 43-52 ◽  
Author(s):  
M.D. Filipovic ◽  
J. Horner ◽  
E.J. Crawford ◽  
N.F.H. Tothill ◽  
G.L. White
Keyword(s):  
Mass Extinction ◽  
Milky Way ◽  
The Sun ◽  
Spiral Arms ◽  
New Model ◽  
The Galaxy ◽  
The Times ◽  
Extinction Events ◽  
Mass Extinction Events ◽  
Solar Orbit

We use the most up-to-date Milky Way model and solar orbit data in order to test the hypothesis that the Sun's galactic spiral arm crossings cause mass extinction events on Earth. To do this, we created a new model of the Milky Way's spiral arms by combining a large quantity of data from several surveys. We then combined this model with a recently derived solution for the solar orbit to determine the timing of the Sun's historical passages through the Galaxy's spiral arms. Our new model was designed with a symmetrical appearance, with the major alteration being the addition of a spur at the far side of the Galaxy. A correlation was found between the times at which the Sun crosses the spiral arms and six known mass extinction events. Furthermore, we identify five additional historical mass extinction events that might be explained by the motion of the Sun around our Galaxy. These five additional significant drops in marine genera that we find include significant reductions in diversity at 415, 322, 300, 145 and 33 Myr ago. Our simulations indicate that the Sun has spent ~60% of its time passing through our Galaxy's various spiral arms. Also, we briefly discuss and combine previous work on the Galactic Habitable Zone with the new Milky Way model.

scholarly journals A new model for the infrared emission of IRAS F10214+4724

2011 ◽  
Vol 7 (S284) ◽  
pp. 205-209
Author(s):  
Andreas Efstathiou ◽  
Natalie Christopher ◽  
Aprajita Verma ◽  
Ralf Siebenmorgen
Keyword(s):  
Energy Distribution ◽  
Gravitational Lensing ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Infrared Emission ◽  
Spectral Energy ◽  
New Model ◽  
Average Spectrum ◽  
Line Region ◽  
The Galaxy

AbstractWe present a new model for the infrared emission of the high redshift hyperluminous infrared galaxy IRAS F10214+4724 which takes into account recent photometric data from Spitzer and Herschel that sample the peak of its spectral energy distribution. We first demonstrate that the combination of the AGN tapered disc and starburst models of Efstathiou and coworkers, while able to give an excellent fit to the average spectrum of type 2 AGN measured by Spitzer, fails to match the spectral energy distribution of IRAS F10214+4724. This is mainly due to the fact that the ν Sν distribution of the galaxy falls very steeply with increasing frequency (a characteristic of heavy absorption by dust) but shows a silicate feature in emission. We propose a model that assumes two components of emission: clouds that are associated with the narrow-line region and a highly obscured starburst. The emission from the clouds must suffer significantly stronger gravitational lensing compared to the emission from the torus to explain the observed spectral energy distribution.

scholarly journals Near-infrared studies of the Milky Way

1985 ◽  
Vol 106 ◽  
pp. 123-126 ◽  
Author(s):  
H. Okuda
Keyword(s):  
Near Infrared ◽  
Milky Way ◽  
Field Configuration ◽  
Magnetic Field Configuration ◽  
Infrared Observations ◽  
Infrared Studies ◽  
The Galaxy ◽  
Inner Region ◽  
The Magnetic Field ◽  
Infrared Brightness

The inner region of the Galaxy has been explored by means of near-infrared observations; the distribution and population of the stars are studied from the near-infrared brightness mapping and star counts in the Milky Way, while the magnetic-field configuration is probed by the near-infrared polarimetry.

Statistical criteria of stellar population types

1966 ◽  
Vol 24 ◽  
pp. 101-110
Author(s):  
W. Iwanowska
Keyword(s):  
Stellar Population ◽  
Chemical Properties ◽  
Spectrophotometric Study ◽  
Physical And Chemical Properties ◽  
Population Type ◽  
The Galaxy ◽  
Distribution Parameters ◽  
Physical And Chemical ◽  
Statistical Criteria ◽  
And Chemical Properties

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.

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