Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 33 for “"Gyr"”.
-
Rotational evolution between 120 Myr and 1 Gyr
… stelle definite "slow-rotators" tra 100Myr e 1 Gyr. Questa analisi ha delineato un comportamento complesso che richiede il miglioramento della modellazione del trasporto interno di momento angolare e della perdita di momento angolare attraverso il vento magnetizzato. Lascia perlessi il …
-
Modelling biogeochemical controls on planetary habitability
… within habitable temperature limits for 6.34 Gyr (1.8 Gyr from present), but photosynthetic primary producers will experience carbon-starvation due to greatly increased terrestrial weathering from 5.38 Gyr (0.84 Gyr from present) onwards, with significant implications for planetary …
-
Disentangling the chemodynamical history of the Milky Way disc with asteroseismology and spectroscopy
… kpc) and a large age baseline (0.5 Gyr $\lesssim \tau\lesssim$ 13 Gyr), allowing us to study the age- and radius-dependence of the [$\alpha$/Fe] vs. [Fe/H] distributions. We find that the age distribution of the high-[$\alpha$/Fe] sequence appears to be broader than expected from a …
-
Constraining the Major Merging History of Massive Galaxies: A Comprehensive Analysis of Close Pairs and Tidal Features Using Empirical and Simulated Data
… during the key epoch of galaxy growth (7-11 Gyr ago), highlighting that the merger contribution to galaxy growth remains poorly constrained. As a step towards addressing key open questions pertaining to empirical merger identification methodologies, we carryout comprehensive analysis of close …
-
Jet Definitions in Effective Field Theory and Decaying Dark Matter
… dark matter are constrained by Gamma^{-1} > 100 Gyr and (f*Gamma)^{-1} > 5.3 x 10^8 Gyr (at 95.4% confidence level), where the phenomenological parameter f is the fraction of decay energy deposited into the baryonic gas. This allows us to constrain particle physics models with dark matter …
-
Development and Testing of a New Method for Velocity-Selecting White Dwarfs from Gaia by Galactic Population
… distribution which is singly-peaked near 6 Gyr, with a peak FWHM of 0.64 Gyr. This may suggest that the sample of high-velocity white dwarfs in the solar neighbourhood is contaminated by stars from a later merger event, supernovae within prior binaries, or gravitational scattering due to …
-
Chemical abundance analysis of HE 2324-0215, an r-process-enhanced metal-poor star
… decay, resulting in the age of 13.0 ± 1.0 Gyr. The age and the metallicity of the star suggest that HE 2324-0215 formed in a dwarf galaxy which was later accreted and became part of the Milky Way.
-
Regiões genómicas associadas à variação da coloração da pelagem em bovinos da raça GIR
… mechanisms that explain coat variations in Gyr cattle, the objective was to perform a GWAS to identify candidate genes for the coat phenotype and perform fine mapping of the MC1R gene, a gene that has already been reported to affect the coat in other cattle breeds. A total of 574 Gir animals …
-
A thermotectonic framework for the growth and stabilization of the eastern Kaapvaal craton, southern Africa
… crust and mantle lithosphere assembled over -4 Gyr and are therefore our best record of the early Earth. Exposures of rocks -3.0-3.7 Ga cover -20,000 km2 of eastern S. Africa and Swaziland, and provide a record of the continental assembly and subsequent stabilization of the eastern Kaapvaal …
-
Surfing the Bar to the Solar Circle
… the cluster is estimated to be approximately 8 Gyr old. Despite experiencing evaporation and tidal shocks, this cluster still exists defying expectations of its impending dissolution. With this purpose, a suite of tracer particle simulations are created to explore the orbits of stars placed at …
-
Evolution of Supermassive Black Hole Feedback in Galaxy Clusters
… central galaxies and SMBHs spanning almost 10 Gyr of cosmic evolution. By studying how the largest galaxies and black holes in the universe co-evolve under extreme and chaotic environments, we can gain a great deal of insight into how the universe we see around us today came to be.
-
The Formation of Distal Impact Ejecta
… flux on Earth was significantly higher ~2-3.5 Gyr ago than it is today. Our model for the less energetic material ejected as part of the ejecta curtain predicts how ejecta particle sizes depend on impactor size and ejection velocity. In the future, this model can also be used to estimate the …
-
Intergalactic baryon enrichment and implications for galaxy evolution at high redshift
… and intergalactic gas in the first several Gyr of the Universe. At z ~ 3.5, we study chemical abundances of Lyman limit systems (LLSs) and evaluate their potential to represent expected reservoirs of cold, low-metallicity gas whose accretion onto galaxies is necessary to maintain star …
-
Star-forming Galaxies and Quenched Systems throughout Cosmic Time
… find the target to have been quiescent for 0.6 Gyr with a mass-weighted average stellar age of 0.8 - 1.7 Gyr (dominated by systematics). The galaxy displays a colour gradient (redder towards the edge), consistent with outside-in, environment-driven quenching. Based on a combination of …
-
Precision CCD photometry of globular clusters
… The age of the cluster is determined as 16 +3 Gyr, by comparison with theoretical isochrones. This result is consistent with recent determinations for other clusters, and supports the theory that the Galactic globular cluster system is essentially coeval. The cluster main sequence luminosity …
-
Search for post-starburst (E+A) galaxies in the cluster Abell 3266
… than one merger in this cluster in the past 3 Gyr or so. This might explain the rather disparate conclusions that have been obtained in the past about the merger history of this cluster. To compare with other nearby clusters, "E+A" galaxies were also searched for among nearly 2400 galaxies in …
-
Dual active galactic nuclei within Romulus25
… are rarely in post-merger galaxies and are > 1 Gyr away from their SMBHs merging. We also identify a novel in-situ formation channel for DAGNs that does not require any galaxy merger, which is afforded to the Romulus25 simulation due to its unique SMBH seeding prescription, and quantify how much …
-
A spectroscopic and photometric study of stellar populations in a sample of clusters in the Magellanic Clouds
… 9 LMC clusters (with ages between 100 Myr and 13 Gyr) with the optical high-resolution spectrograph FLAMES@VLT (ESO, Paranal) and 4 very young (<30 Myr) clusters (3 in the LMC and 1 in the SMC) with the near-infrared high-resolution spectrograph CRIRES@VLT. • The study of the photometric …
-
Characterizing sub-mm observations of protoplanetary disks at super-resolution scales
… as astrophysical objects across epochs that span Gyr of evolution, from their formation in protoplanetary disks and continued growth in debris disks to their dynamical evolution in exoplanetary systems and ultimate accretion onto white dwarfs. Measurements in each of these eras can be used to …
-
Near-IR Spectroscopic Analysis of the Primary Volatile Composition of Long and Short-Period Comets
… that formed in the protosolar nebula ∼4.5 Gyr ago. Hence, they are important for understanding various aspects of the formation, evolution, and habitability of the solar system. Multiple primary volatiles (molecules directly sublimating into the coma from the nucleus) emit via rovibrational …
Page 1 of 2