Star formation history and dynamical evolution of the solar neighbourhood

2017 ◽  
Vol 13 (S334) ◽  
pp. 310-311
Author(s):  
Andreas Just ◽  
Kseniia Sysoliatina
Keyword(s):  
Star Formation ◽  
Galactic Plane ◽  
Dynamical Evolution ◽  
Star Formation History ◽  
Solar Neighbourhood ◽  
Data Set ◽  
Disc Model ◽  
Formation History ◽  
Number Counts ◽  
Good Agreement

AbstractWe used our detailed analytic local disc model to compare predictions in number counts, colour distribuitons and kinematics with a data set extracted from a combination of TGAS and RAVE catalogues. We find generally a very good agreement with some deviations close to the Galactic plane.

scholarly journals An Evolutionary Disc Model of NGC 5907

2006 ◽  
Vol 2 (S235) ◽  
pp. 112-112
Author(s):  
Andreas Just ◽  
C. Möllenhoff ◽  
A. Borch
Keyword(s):  
Star Formation ◽  
Dynamical Evolution ◽  
Star Formation History ◽  
Dust Extinction ◽  
Disc Model ◽  
Formation History ◽  
Multi Band

AbstractWe present the first physical disc model of NGC 5907, which reproduces simultaneouly the multi-band photometry in U, B, V, R, and I- band (Just et al., 2006, A&A in press, astro-ph/0608196). The model is based on the star formation history and dynamical evolution of the disc and includes dust extinction consistent with the dust properties derived from FIR observations. We also find naturally the stellar light eccess of the young sub-population near the midplane (hidden by the dust), which is required to heat the dust.

scholarly journals Star formation history of the solar neighbourhood as told by Gaia

2020 ◽  
Vol 501 (1) ◽  
pp. 302-328
Author(s):  
Jairo A Alzate ◽  
Gustavo Bruzual ◽  
Daniel J Díaz-González
Keyword(s):  
Star Formation ◽  
Binary Stars ◽  
Mass Function ◽  
Initial Mass Function ◽  
Star Formation History ◽  
Solar Neighbourhood ◽  
Data Set ◽  
Formation History ◽  
Solar Metallicity ◽  
History Of

ABSTRACT The Gaia data release 2 (DR2) catalogue is the best source of stellar astrometric and photometric data available today. The history of the Milky Way galaxy is written in stone in this data set. Parallaxes and photometry tell us where the stars are today, when were they formed, and with what chemical content, that is, their star formation history (SFH). We develop a Bayesian hierarchical model suited to reconstruct the SFH of a resolved stellar population. We study the stars brighter than $G\, =\, 15$ within 100 pc of the Sun in Gaia DR2 and derive an SFH of the solar neighbourhood in agreement with previous determinations and improving upon them because we detect chemical enrichment. Our results show a maximum of star formation activity about 10 Gyr ago, producing large numbers of stars with slightly below solar metallicity (Z  =  0.014), followed by a decrease in star formation up to a minimum level occurring around 8 Gyr ago. After a quiet period, star formation rises to a maximum at about 5 Gyr ago, forming stars of solar metallicity (Z  =  0.017). Finally, star formation has been decreasing until the present, forming stars of Z  =  0.03 at a residual level. We test the effects introduced in the inferred SFH by ignoring the presence of unresolved binary stars in the sample, reducing the apparent limiting magnitude, and modifying the stellar initial mass function.

scholarly journals Gaia DR1 completeness within 250 pc & star formation history of the Solar neighbourhood

2017 ◽  
Vol 12 (S330) ◽  
pp. 148-151 ◽  
Author(s):  
Edouard J. Bernard
Keyword(s):  
Star Formation ◽  
Star Formation History ◽  
Solar Neighbourhood ◽  
The Sun ◽  
Thick Disc ◽  
Formation History ◽  
Magnitude Diagram ◽  
History Of

AbstractWe took advantage of the Gaia DR1 to combine TGAS parallaxes with Tycho-2 and APASS photometry to calculate the star formation history (SFH) of the solar neighbourhood within 250 pc using the colour-magnitude diagram fitting technique. We present the determination of the completeness within this volume, and compare the resulting SFH with that calculated from the Hipparcos catalogue within 80 pc of the Sun. We also show how this technique will be applied out to ~5 kpc thanks to the next Gaia data releases, which will allow us to quantify the SFH of the thin disc, thick disc and halo in situ, rather than extrapolating based on the stars from these components that are today in the solar neighbourhood.

scholarly journals BGM FASt: Besançon Galaxy Model for big data

2018 ◽  
Vol 620 ◽  
pp. A79 ◽  
Author(s):  
R. Mor ◽  
A. C. Robin ◽  
F. Figueras ◽  
T. Antoja
Keyword(s):  
Distribution Function ◽  
Star Formation ◽  
Mass Density ◽  
Mass Range ◽  
Star Formation History ◽  
Solar Neighbourhood ◽  
Parameter Inference ◽  
Formation History ◽  
Galaxy Model ◽  
Validation Tests

Aims. We develop a new theoretical framework to generate Besançon Galaxy Model Fast Approximate Simulations (BGM FASt) to address fundamental questions of the Galactic structure and evolution performing multi-parameter inference. As a first application of our strategy we simultaneously infer the initial-mass function (IMF), the star formation history and the stellar mass density in the solar neighbourhood. Methods. The BGM FASt strategy is based on a reweighing scheme, that uses a specific pre-sampled simulation, and on the assumption that the distribution function of the generated stars in the Galaxy can be described by an analytical expression. To evaluate the performance of our strategy we execute a set of validation tests. Finally, we use BGM FASt together with an approximate Bayesian computation algorithm to obtain the posterior probability distribution function of the inferred parameters, by automatically comparing synthetic versus Tycho-2 colour-magnitude diagrams. Results. The validation tests show a very good agreement between equivalent simulations performed with BGM FASt and the standard BGM code, with BGM FASt being ∼104 times faster. From the analysis of the Tycho-2 data we obtain a thin-disc star formation history decreasing in time and a present rate of 1.2 ± 0.2 M ⊙ yr−1. The resulting total stellar volume mass density in the solar neighbourhood is 0.051−0.005+0.002 M⊙ pc−3 and the local dark matter density is 0.012 ± 0.001 M ⊙ pc−3. For the composite IMF, we obtain a slope of α2 = 2.1−0.3+0.1 in the mass range between 0.5 M⊙ and 1.53 M⊙. The results of the slope at the high-mass range are trustable up to 4 M⊙ and highly dependent on the choice of extinction map (obtaining α3 = 2.9−0.2+0.2 and α3 = 3.7−0.2+0.2, respectively, for two different extinction maps). Systematic uncertainties coming from model assumptions are not included. Conclusions. The good performance of BGM FASt demonstrates that it is a very valuable tool to perform multi-parameter inference using Gaia data releases.

Reconstructing the star formation history of the Solar neighbourhood with Gaia

2017 ◽  
Vol 13 (S334) ◽  
pp. 158-161
Author(s):  
Edouard J. Bernard
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Star Formation History ◽  
Solar Neighbourhood ◽  
The Past ◽  
Formation History ◽  
Magnitude Diagram ◽  
History Of

AbstractTaking advantage of the Gaia DR1, we combined TGAS parallaxes with the Tycho-2 and APASS photometry to calculate the star formation history (SFH) of the solar neighbourhood within 250 pc using the colour-magnitude diagram fitting technique. Our dynamically-evolved SFH is in excellent agreement with that calculated from the Hipparcos catalogue within 80 pc of the Sun, showing an enhanced star formation rate (SFR) in the past ~4 Gyr. We then correct the SFR for the disc thickening with age to obtain a SFR that is representative of the whole solar cylinder, and show that even with an extreme correction our results are not consistent with an exponentially decreasing SFR as found by recent studies. Finally, we discuss how this technique can be applied out to ~5 kpc thanks to the next Gaia data releases, which will allow us to quantify the SFH of the thin disc, thick disc and halo in situ.

scholarly journals Galactic Archaeology with TESS: Prospects for Testing the Star Formation History in the Solar Neighbourhood

2017 ◽  
Vol 160 ◽  
pp. 05006
Author(s):  
Alexandra Thomas ◽  
Emma Stevenson ◽  
Fabian W. R. Gittins ◽  
Andrea Miglio ◽  
Guy Davies ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation History ◽  
Solar Neighbourhood ◽  
Formation History

scholarly journals Wide-area photometric and astrometric (Gaia DR2) study of the young cluster NGC 6530

2019 ◽  
Vol 623 ◽  
pp. A25 ◽  
Author(s):  
F. Damiani ◽  
L. Prisinzano ◽  
G. Micela ◽  
S. Sciortino
Keyword(s):  
Star Formation ◽  
Galactic Plane ◽  
Star Formation History ◽  
Cluster Membership ◽  
Motion Data ◽  
Main Cluster ◽  
Near Ir ◽  
Formation History ◽  
Great Confidence ◽  
Cluster Distance

Context. NGC 6530 is a young cluster, with a complex morphology and star-formation history. We present a statistical study of its global properties, using a new, large list of candidate members down to masses of 0.2−0.4 M⊙ and Gaia DR2 astrometry. Aims. We consider a larger sky region compared to previous studies, to investigate the entire cluster until its periphery, including any diffuse population all around the main cluster. We study the distribution of extinction and age across the different regions, and obtain constraints on the star-formation history. We also study the dynamics of cluster members. Methods. Cluster membership was determined on the basis of literature X-ray data, Hα emission, near-IR and UV excesses from the VPHAS+ and UKIDSS photometric surveys and published near-IR catalogs, and Gaia DR2 astrometry; moreover, we used a method for photometric selection of M-type pre-main-sequence cluster members, which we recently developed and used for other star-formation regions. The list of candidates includes nearly 3700 stars, of which we estimate approximately 2700 to be genuine NGC 6530 members. Results. Using Gaia parallaxes, the cluster distance is found to be 1325 pc, with errors of 0.5% (statistical) and 8.5% (systematic), in agreement with previous determinations. The cluster morphology and boundaries are established with great confidence, from the agreement between the subsamples of members selected using different criteria. There is no diffuse population of members around the cluster, but there are minor condensations of true members in addition to the two main groups in the cluster core and in the Hourglass nebula. Two such subgroups are spatially associated with the stars 7 Sgr (F2II-III) and HD 164536 (O7.5V). There is a definite pattern of sequential star formation across the cluster, within an age range from less than 0.5 Myr to ∼5 Myr. Extinction is spatially non-uniform, with part of the population still embedded or obscured by thick dust. The precise Gaia proper motion data indicate that the NGC 6530 parent cloud collided with the Galactic plane around 4 Myr ago, and we suggest that event as the trigger of the bulk of star formation in NGC 6530. The internal cluster dynamics is also partially resolved by the Gaia data, indicating expansion of the main cluster population with respect to its center.

Star formation history and dynamical evolution of the solar neighbourhood

2018 ◽  
Vol 14 (S344) ◽  
pp. 90-93
Author(s):  
Andreas Just ◽  
Reza Moetazedian ◽  
Evgeny Polyachenko
Keyword(s):  
Star Formation ◽  
Dynamical Evolution ◽  
Star Formation History ◽  
Minor Effect ◽  
Thin Disc ◽  
Formation History ◽  
Satellite Galaxies ◽  
A Minor ◽  
The Impact ◽  
Bar Formation

AbstractBased on cosmological re-simulations we have shown that the impact of satellite galaxies has a minor effect on the thin disc heating. In contrast satellite galaxies can generate long-lived warps of the outer disc and they can advance or delay bar formation significantly.

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