相关论文: New Radiative and Collisional Atomic Data for Sr {…

Yttrium (Y), a key s-process element, is commonly used in nucleosynthesis studies and as a Galactic chemical clock when combined with magnesium (Mg). We study the applicability of the previously assumed LTE line formation assumption in Y…

The neutron star merger is a promising site of heavy element production. By producing heavy elements, the neutron star merger gives rise to a thermal transient called a kilonova. Studying kilonova spectra enables us to quantify the heavy…

Kilonovae are key to advancing our understanding of r-process nucleosynthesis. To date, only two kilonovae have been spectroscopically observed, AT 2017gfo and AT 2023vfi. Here, we present an analysis of the James Webb Space Telescope…

The dominant site(s) of the $r$-process are a subject of current debate. Ejecta from $r$-process enrichment events like kilonovae are difficult to directly measure, so we must instead probe abundances in metal-poor stars to constrain…

Kilonovae are likely a key site of heavy r-process element production in the Universe, and their optical/infrared spectra contain insights into both the properties of the ejecta and the conditions of the r-process. However, the event…

Kilonova spectra provide us with the direct information of r-process nucleosynthesis in neutron star mergers. In this paper, we study the signatures of elements beyond the third r-process peak expected to be produced in neutron-rich ejecta…

Kilonovae, the electromagnetic transients produced from two merging neutron stars, exhibit evolving spectral signatures in ultraviolet, visible, and infrared radiation. Starting around one week post-merger, equilibrium assumptions…

The kilonova (KN) associated with the binary neutron star (BNS) merger GW170817 is the only known electromagnetic counterpart to a gravitational wave source. Here we produce a sequence of radiative transfer models (using $\textsc{tardis}$)…

We present the spectroscopic and photometric study of five intermediate-luminosity red transients (ILRTs), namely AT 2010dn, AT 2012jc, AT 2013la, AT 2013lb, and AT 2018aes. They share common observational properties and belong to a family…

Results of calculations for inelastic e+Mg effective collision strengths for the lowest 25 physical states of Mg I (up to 3s6p 1P), and thus 300 transitions, from the convergent close-coupling (CCC) and the B-spline R-matrix (BSR) methods…

The observations of GW170817/AT2017gfo have provided us with evidence that binary neutron star mergers are sites of $r$-process nucleosynthesis. However, the observed signatures in the spectra of GW170817/AT2017gfo have not been fully…

The spectral features in the optical/near-infrared counterparts of neutron star mergers (kilonovae, KNe), evolve dramatically on hour timescales. To examine the spectral evolution we compile a temporal series complete at all observed epochs…

The characteristic rapid rise and decline at optical wavelengths of a kilonova is the product of the low ejecta mass ($\lesssim 0.05 M_\odot$) and high ejecta velocity ($\gtrsim 0.1$c). We show that, even at very early times ($\lesssim 2$…

We investigate the role of hydrogen collisions in NLTE spectral line synthesis, and introduce a new general empirical recipe to determine inelastic charge transfer (CT) and bound-bound hydrogen collisional rates. This recipe is based on…

More than 3000 spectroscopically confirmed Type Ia supernovae (SNe Ia) are presented in the Zwicky Transient Facility SN Ia Data Release 2 (ZTF DR2). In this paper, we detail the spectral properties of 482 SNe Ia near maximum light, up to a…

We obtained optical and near-infrared spectra of Type$\,$Ia supernovae (SNe$\,$Ia) at epochs ranging from 224 to 496 days after the explosion. The spectra show emission lines from forbidden transitions of singly ionised iron and cobalt…

We have calculated fast direct spectral model fits to two early-time spectra of the Type-II plateau SN 1999em, using the SYNOW synthetic spectrum code. The first is an extremely early blue optical spectrum and the second a combined HST and…

We perform the non-local thermodynamic equilibrium (NLTE) calculations for Ca I-II with the updated model atom that includes new quantum-mechanical rate coefficients for Ca I + H I collisions from two recent studies, that is, by Barklem and…

We measure the spectrum of tellurium-130 in the vicinity of the 461~nm ${}^1\text{S}_0-{}^{1}\text{P}_1$ cycling transition in neutral strontium, a popular element for atomic clocks, quantum information, and quantum-degenerate gases. The…

We present extensive calculations of radiative transition rates and electron impact collision strengths for Fe II. The data sets involve 52 levels from the $3d\,^7$, $3d\,^64s$, and $3d\,^54s^2$ configurations. Computations of $A$-values…