scholarly journals The Galactic bulge: a review

2007 ◽  
Vol 3 (S245) ◽  
pp. 323-332 ◽  
Author(s):  
Dante Minniti ◽  
Manuela Zoccali
Keyword(s):  
Chemical Composition ◽  
Central Region ◽  
Milky Way ◽  
Galactic Center ◽  
Current Understanding ◽  
Ir Detectors ◽  
Individual Stars ◽  
Near Ir ◽  
Great Progress ◽  
Formation And Evolution

AbstractThe Milky Way is the only galaxy for which we can resolve individual stars at all evolutionary phases, from the Galactic center to the outskirt. The last decade, thanks to the advent of near IR detectors and 8 meter class telescopes, has seen a great progress in the understanding of the Milky Way central region: the bulge. Here we review the most recent results regarding the bulge structure, age, kinematics and chemical composition. These results have profound implications for the formation and evolution of the Milky Way and of galaxies in general. This paper provides a summary on our current understanding of the Milky Way bulge, intended mainly for workers on other fields.

scholarly journals The Distance to the Galactic Center: RO

1989 ◽  
Vol 136 ◽  
pp. 37-46 ◽  
Author(s):  
Mark J. Reid
Keyword(s):  
Milky Way ◽  
Galactic Center ◽  
Best Value ◽  
Great Progress ◽  
The Galaxy

Great progress has been made toward measuring the size of the Milky Way. There are now several methods that employ independent calibrations to estimate the distance to the center of the Galaxy, Ro, and these methods have been applied to many types of astronomical objects. Ro estimates generally have been decreasing over the last 15 years. At this time a reasonable “best value” estimate for Ro is 7.7 ± 0.7 kpc.

scholarly journals Galaxy simulations in the Gaia era

2017 ◽  
Vol 12 (S330) ◽  
pp. 127-135
Author(s):  
Ivan Minchev
Keyword(s):  
Chemical Composition ◽  
Numerical Simulations ◽  
Spectroscopic Data ◽  
Milky Way ◽  
Disk Galaxies ◽  
Physical Processes ◽  
Radial Migration ◽  
Cosmological Context ◽  
Enormous Amount ◽  
Formation And Evolution

AbstractWe live in an age where an enormous amount of astrometric, photometric, asteroseismic, and spectroscopic data of Milky Way stars are being acquired, many orders of magnitude larger than about a decade ago. Thanks to the Gaia astrometric mission and followup ground-based spectroscopic surveys in the next 5-10 years about 10-20 Million stars will have accurate 6D kinematics and chemical composition measurements. KEPLER-2, PLATO, and TESS will provide asteroseismic ages for a good fraction of those. In this article we outline some outstanding problems concerning the formation and evolution of the Milky Way and argue that, due to the complexity of physical processes involved in the formation of disk galaxies, numerical simulations in the cosmological context are needed for the interpretation of Milky Way observations. We also discuss in some detail the formation of the Milky Way thick disk, chemodynamical models, and the effects of radial migration.

scholarly journals The Formation and Evolution of ONe White Dwarfs: Prospects for Accretion Induced Collapse

2011 ◽  
Vol 7 (S281) ◽  
pp. 52-59
Author(s):  
Enrique García–Berro
Keyword(s):  
Chemical Composition ◽  
Mass Loss ◽  
Electron Capture ◽  
White Dwarfs ◽  
Stellar Mass ◽  
Asymptotic Giant Branch ◽  
Current Understanding ◽  
Convective Mixing ◽  
Formation And Evolution ◽  
Carbon Burning

AbstractI review our current understanding of the evolution of stars which experience carbon burning under conditions of partial electron degeneracy and ultimately become thermally pulsing “super” asymptotic giant branch (SAGB) stars with electron-degenerate cores composed primarily of oxygen and neon. The range in stellar mass over which this occurs is very narrow and the interior evolutionary characteristics vary rapidly over this range. Consequently, while those stars with larger masses (~11 M⊙) are likely to undergo electron-capture accretion induced collapse, those models with smaller masses (8.5 ≲ M/M⊙ ≲ 10.5) will presumably form massive (M ≳ 1.1 M⊙) white dwarfs. The final outcome depends sensitively on the adopted mass-loss rates, the chemical composition of the massive envelopes, and on the adopted prescription for convective mixing.

scholarly journals Galactic dynamics feeding the Galactic center

2013 ◽  
Vol 9 (S303) ◽  
pp. 174-176
Author(s):  
Florent Renaud ◽  
Eric Emsellem ◽  
Frédéric Bournaud
Keyword(s):  
Black Hole ◽  
Hierarchical Structure ◽  
Central Region ◽  
Milky Way ◽  
Galactic Center ◽  
Rapid Evolution ◽  
Galactic Dynamics ◽  
Supermassive Black Hole ◽  
The Hierarchical Structure

AbstractWe present the hierarchical structure of the gas and its rapid evolution in the central region of a simulation of the entire Milky Way, run at subparsec resolution. We emphasize the coupling between the kpc-scale dynamics, the molecular ring and the central 5 pc disk feeding the supermassive black hole.

scholarly journals CNO abundances in the Galactic bulge

2009 ◽  
Vol 5 (S265) ◽  
pp. 285-288
Author(s):  
Nils A. E. Ryde
Keyword(s):  
Ir Spectra ◽  
Milky Way ◽  
Recent Analysis ◽  
Line Of Sight ◽  
Galactic Bulge ◽  
Elemental Abundances ◽  
Near Ir ◽  
Visual Extinction ◽  
Formation And Evolution ◽  
Cno Abundances

AbstractThe carbon, nitrogen, and oxygen abundances and trends in the bulge are discussed in the context of our recent analysis of these elements in an on-going project based on near-IR spectra (Ryde et al. 2009). We obtained these using the CRIRES spectrometer on the VLT. The formation and evolution of the Milky Way bulge can be constrained by studying elemental abundances of bulge stars. Due to the large and variable visual extinction in the line-of-sight towards the bulge, an analysis in the near-IR is preferred.

scholarly journals Unveiling the Secrets of the Galactic bulge through stellar abundances in the near-IR: a VLT/Crires project

2008 ◽  
Vol 4 (S254) ◽  
pp. 159-164
Author(s):  
Nils Ryde
Keyword(s):  
Milky Way ◽  
Line Of Sight ◽  
Galactic Bulge ◽  
Stellar Abundances ◽  
Preliminary Results ◽  
Elemental Abundances ◽  
Near Ir ◽  
Visual Extinction ◽  
Formation And Evolution

AbstractThe formation and evolution of the Milky Way bulge can be constrained by studying elemental abundances of bulge stars. Due to the large and variable visual extinction in the line-of-sight towards the bulge, an analysis in the near-IR is preferred. Here, I will present some preliminary results of an on-going project in which elemental abundances, especially those of the C, N, and O elements, of bulge stars are investigated by analysing CRIRES spectra observed with the VLT.

scholarly journals Impact of solar radiation and environmental temperature on Art Nouveau glass windows

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Teresa Palomar ◽  
Miguel Silva ◽  
Marcia Vilarigues ◽  
Isabel Pombo Cardoso ◽  
David Giovannacci
Keyword(s):  
Chemical Composition ◽  
Solar Radiation ◽  
Surface Temperature ◽  
Environmental Temperature ◽  
Summer Solstice ◽  
Art Nouveau ◽  
Ir Thermography ◽  
Hot Air ◽  
Near Ir ◽  
Air Pocket

Abstract This work presents the results of the evaluation of two Art Nouveau glass windows from the Casa-Museu Dr. Anastácio Gonçalves (Lisbon, Portugal) with IR-thermography during the summer solstice. According to the measurements, the surface temperature of glass depended on the outdoor environmental temperature and, mainly, on the direct solar radiation. Colored glasses presented a higher surface temperature due to the absorption of their chromophores at near-IR wavelengths. Enamels and grisailles showed higher surface temperatures than their support glasses due to both their chemical composition and color. The protective glazing, with small slits in one of the window panels, induced a hot-air pocket in its upper part due to the insufficient ventilation.

scholarly journals An Atmospheric Origin for HCN-Derived Polymers on Titan

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 965
Author(s):  
Zoé Perrin ◽  
Nathalie Carrasco ◽  
Audrey Chatain ◽  
Lora Jovanovic ◽  
Ludovic Vettier ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Gas Phase ◽  
Formation Process ◽  
Upper Atmosphere ◽  
Gas Mixture ◽  
Space Probe ◽  
Atmospheric Haze ◽  
Formation And Evolution ◽  
Haze Formation

Titan’s haze is strongly suspected to be an HCN-derived polymer, but despite the first in situ measurements by the ESA-Huygens space probe, its chemical composition and formation process remain largely unknown. To investigate this question, we simulated the atmospheric haze formation process, experimentally. We synthesized analogues of Titan’s haze, named Titan tholins, in an irradiated N2–CH4 gas mixture, mimicking Titan’s upper atmosphere chemistry. HCN was monitored in situ in the gas phase simultaneously with the formation and evolution of the haze particles. We show that HCN is produced as long as the particles are absent, and is then progressively consumed when the particles appear and grow. This work highlights HCN as an effective precursor of Titan’s haze and confirms the HCN-derived polymer nature of the haze.

scholarly journals A Statistical Estimation of the Occurrence of Extraterrestrial Intelligence in the Milky Way Galaxy

Galaxies ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 5
Author(s):  
Xiang Cai ◽  
Jonathan H. Jiang ◽  
Kristen A. Fahy ◽  
Yuk L. Yung
Keyword(s):  
Statistical Estimation ◽  
Milky Way ◽  
Galactic Center ◽  
Model Simulation ◽  
Temporal Variations ◽  
Extraterrestrial Intelligence ◽  
Milky Way Galaxy ◽  
The Galaxy ◽  
Peak Location ◽  
Intelligent Life

In the field of astrobiology, the precise location, prevalence, and age of potential extraterrestrial intelligence (ETI) have not been explicitly explored. Here, we address these inquiries using an empirical galactic simulation model to analyze the spatial–temporal variations and the prevalence of potential ETI within the Galaxy. This model estimates the occurrence of ETI, providing guidance on where to look for intelligent life in the Search for ETI (SETI) with a set of criteria, including well-established astrophysical properties of the Milky Way. Further, typically overlooked factors such as the process of abiogenesis, different evolutionary timescales, and potential self-annihilation are incorporated to explore the growth propensity of ETI. We examine three major parameters: (1) the likelihood rate of abiogenesis (λA); (2) evolutionary timescales (Tevo); and (3) probability of self-annihilation of complex life (Pann). We found Pann to be the most influential parameter determining the quantity and age of galactic intelligent life. Our model simulation also identified a peak location for ETI at an annular region approximately 4 kpc from the galactic center around 8 billion years (Gyrs), with complex life decreasing temporally and spatially from the peak point, asserting a high likelihood of intelligent life in the galactic inner disk. The simulated age distributions also suggest that most of the intelligent life in our galaxy are young, thus making observation or detection difficult.

scholarly journals Radial metallicity gradients with Galactic nebular probes

2018 ◽  
Vol 14 (A30) ◽  
pp. 240-241 ◽  
Author(s):  
Jorge García-Rojas
Keyword(s):  
Milky Way ◽  
Galactic Disc ◽  
Formation And Evolution

AbstractThe study of radial metallicity gradients in the disc of the Milky Way is a powerful tool to understand the mechamisms that have been acting in the formation and evolution of the Galactic disc. In this proceeding, I will put the eye on some problems that should be carefully addressed to obtain precise determinations of the metallicity gradients.

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