1. Chatzikos, M. and Bianchi, S. and Camilloni, F. and Chakraborty, P. and Gunasekera, C. M. and Guzm{\'a}n, F. and Milby, J. S. and Sarkar, A. and Shaw, G. and van Hoof, P. A. M. and Ferland, G. J. (2023) The 2023 Release of Cloudy. \rmxaa 59: 327-343 https://doi.org/10.22201/ia.01851101p.2023.59.02.12, https://ui.adsabs.harvard.edu/abs/2023RMxAA..59..327C, astro-ph.GA, atomic data, galaxies: active, globular clusters: general, molecular data, software: development, Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena, 软 件, 2308.06396, arXiv, We describe the 2023 release of the spectral synthesis code Cloudy. Since the previous major release, migrations of our online services motivated us to adopt git as our version control system. This change alone led us to adopt an annual release scheme, accompanied by a short release paper, the present being the inaugural. Significant changes to our atomic and molecular data have improved the accuracy of Cloudy predictions: we have upgraded our instance of the Chianti database from version 7 to 10; our H- and He-like collisional rates to improved theoretical values; our molecular data to the most recent LAMDA database, and several chemical reaction rates to their most recent UDfA and KiDA values. Finally, we describe our progress on upgrading Cloudy's capabilities to meet the requirements of the X-ray microcalorimeters aboard the upcoming XRISM and Athena missions, and outline future developments that will make Cloudy of use to the X-ray community., October
2. Foreman-Mackey, Daniel and Hogg, David W. and Lang, Dustin and Goodman, Jonathan (2013) emcee: The MCMC Hammer. \pasp 125(925): 306 https://doi.org/10.1086/670067, https://ui.adsabs.harvard.edu/abs/2013PASP..125..306F, astro-ph.IM, Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Computational Physics, Statistics - Computation, 软 件, 1202.3665, arXiv, We introduce a stable, well tested Python implementation of the affine- invariant ensemble sampler for Markov chain Monte Carlo (MCMC) proposed by Goodman & Weare (2010). The code is open source and has already been used in several published projects in the astrophysics literature. The algorithm behind emcee has several advantages over traditional MCMC sampling methods and it has excellent performance as measured by the autocorrelation time (or function calls per independent sample). One major advantage of the algorithm is that it requires hand-tuning of only 1 or 2 parameters compared to {\ensuremath{\sim}}N$$^{2}$$ for a traditional algorithm in an N-dimensional parameter space. In this document, we describe the algorithm and the details of our implementation. Exploiting the parallelism of the ensemble method, emcee permits any user to take advantage of multiple CPU cores without extra effort. The code is available online at http://dan.iel.fm/emcee under the GNU General Public License v2., March
3. Rodriguez-Gomez, Vicente and Snyder, Gregory F. and Lotz, Jennifer M. and Nelson, Dylan and Pillepich, Annalisa and Springel, Volker and Genel, Shy and Weinberger, Rainer and Tacchella, Sandro and Pakmor, R{\"u}diger and Torrey, Paul and Marinacci, Federico and Vogelsberger, Mark and Hernquist, Lars and Thilker, David A. (2019) The optical morphologies of galaxies in the IllustrisTNG simulation: a comparison to Pan-STARRS observations. \mnras 483(3): 4140-4159 https://doi.org/10.1093/mnras/sty3345, https://ui.adsabs.harvard.edu/abs/2019MNRAS.483.4140R, astro-ph.GA, methods: numerical, techniques: image processing, galaxies: formation, galaxies: statistics, galaxies: structure, Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics, :E\:/ 天 翼 云 盘 同 步 盘/17718135778/ 文 献/ 形 态 学/Rodriguez-Gomez-19.pdf:PDF, 1809.08239, arXiv, We have generated synthetic images of {\ensuremath{\sim}}27 000 galaxies from the IllustrisTNG and the original Illustris hydrodynamic cosmological simulations, designed to match Pan-STARRS observations of log$$_{10}$$(M$$_{*}$$/M$$_{{\ensuremath{\odot}}}$$) {\ensuremath{\approx}} 9.8-11.3 galaxies at z {\ensuremath{\approx}} 0.05. Most of our synthetic images were created with the SKIRT radiative transfer code, including the effects of dust attenuation and scattering, and performing the radiative transfer directly on the Voronoi mesh used by the simulations themselves. We have analysed both our synthetic and real Pan-STARRS images with the newly developed statmorph code, which calculates non-parametric morphological diagnostics - including the Gini-M$$_{20}$$ and concentration-asymmetry- smoothness statistics - and performs 2D S{\'e}rsic fits. Overall, we find that the optical morphologies of IllustrisTNG galaxies are in good agreement with observations, and represent a substantial improvement compared to the original Illustris simulation. In particular, the locus of the Gini-M$_{20}$ diagram is consistent with that inferred from observations, while the median trends with stellar mass of all the morphological, size and shape parameters considered in this work lie within the {\ensuremath{\sim}}1{\ensuremath{\sigma}} scatter of the observational trends. However, the IllustrisTNG model has some difficulty with more stringent tests, such as producing a strong morphology-colour relation. This results in a somewhat higher fraction of red discs and blue spheroids compared to observations. Similarly, the morphology-size relation is problematic: while observations show that discs tend to be larger than spheroids at a fixed stellar mass, such a trend is not present in IllustrisTNG., March
4. Yao, Yao and Song, Jie and Kong, Xu and Fang, Guanwen and Zhang, Hong-Xin and Chen, Xinkai (2023) Evolution of Nonparametric Morphology of Galaxies in the JWST CEERS Field at z 0.8-3.0. \apj 954(2): 113 https://doi.org/10.3847/1538-4357/ace7b5, https://ui.adsabs.harvard.edu/abs/2023ApJ...954..113Y, astro-ph.GA, Galaxy classification systems, Galaxy structure, High-redshift galaxies, Galaxy evolution, 582, 622, 734, 594, Astrophysics - Astrophysics of Galaxies, 2307.13975, 113, arXiv, Galaxy morphology is one of the most fundamental ways to describe galaxy properties, but the morphology we observe may be affected by wavelength and spatial resolution, which may introduce systematic bias when comparing galaxies at different redshift. Taking advantage of the broad wavelength coverage from optical to near-IR and the high-resolution NIRCam instrument of the JWST, we measure the nonparametric morphological parameters of a total of 1376 galaxies at z ≃ 0.8-3.0 in the CEERS field through an optimized code called statmorph\_csst. We divide our sample into three redshift intervals and investigate the wavelength and redshift dependence of the morphological parameters. We also explore how the widely used galaxy type classification methods based on the morphological parameters depend on wavelength and spatial resolution. We find that there are variations in all morphological parameters with rest-frame wavelength ({\ensuremath{\lambda}} $$_{rf}$$), especially at the short- wavelength end, and that {\ensuremath{\lambda}} $_{rf}$ mainly affects the classification between late- and early-type galaxies. As {\ensuremath{\lambda}} $_{rf}$ increases, the galaxies on the G-M $$_{20}$$ diagram move to the upper left with a slope of -0.23 {\ensuremath{\pm}} 0.03 on average. We find that spatial resolution mainly affects the merger identification. The merger fraction in F200W resolution can be {\ensuremath{\gtrsim}}2 times larger than that in F444W resolution. Furthermore, we compare the morphological parameter evolution of galaxies with different stellar masses. We find that there are differences in the morphological evolution of high- and low-mass (log M $$_{*}$$ {\ensuremath{\geq}} 10 and 9 < log M $_{*}$ < 10) galaxies in the studied redshift range, which may be caused by their different evolutionary paths., September
5. Conselice, Christopher J. (2014) The Evolution of Galaxy Structure Over Cosmic Time. \araa 52: 291-337 https://doi.org/10.1146/annurev-astro-081913-040037, https://ui.adsabs.harvard.edu/abs/2014ARA &A..52..291C, astro-ph.GA, Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics, :E\:/ 天 翼 云 盘 同 步 盘/17718135778/ 文 献/ 形 态 学/Conselice-14.pdf:PDF, 1403.2783, arXiv, I present a comprehensive review of the evolution of galaxy structure in the Universe from the first galaxies currently observable at z {\ensuremath{\sim}} 6 down to galaxies observable in the local Universe. Observed changes in galaxy structures reveal formation processes that only galaxy structural analyses can provide. This pedagogical review provides a detailed discussion of the major methods used to study galaxies morphologically and structurally, including the well-established visual method for morphology; S{\'e}rsic fitting to measure galaxy sizes and surface brightness profile shapes; and nonparametric structural methods [such as the concentration (C), asymmetry (A), clumpiness (S) (CAS) method and the Gini/M$$_{20}$$ parameters, as well as newer structural indices]. These structural indices measure fundamental properties of galaxies, such as their scale, star- formation rate, and ongoing merger activity. Extensive observational results demonstrate how broad galaxy morphologies and structures change with time up to z {\ensuremath{\sim}} 3, from small, compact and peculiar systems in the distant Universe to the formation of the Hubble sequence, dominated by spirals and ellipticals. Structural methods accurately identify galaxies in mergers and allow measurements of the merger history out to z {\ensuremath{\sim}} 3. I depict properties and evolution of internal structures of galaxies, such as bulges, disks, bars, and at z>1 large star-forming clumps. I describe the structure and morphologies of host galaxies of active galactic nuclei and starbursts/submillimeter galaxies, along with how morphological galaxy quenching occurs. The role of environment in producing structural changes in galaxies over cosmic time is also discussed. Galaxy sizes can also change with time, with measured sizes up to a factor of 2-5 smaller at high redshift at a given stellar mass. I conclude with a discussion of how the evolving trends, in sizes, structures, and morphologies, reveal the formation mechanisms behind galaxies and provides a new and unique way to test theories of galaxy formation., August