In this work we present the photometric and spectroscopic observations of type IIb supernova 2017gpn. This supernova was discovered in the error-box of the LIGO/Virgo G299232 gravitational-wave event. We obtained the light curves in the B and R passbands and modelled them numerically using the one-dimensional radiation hydrocode stella. The best-fitting model has the following parameters: the pre-SN star mass and the radius are M ≈ 3.5 M⊙ and R ≈ 50 R⊙, respectively; the explosion energy is $E_{\rm exp} \approx 1.2\times 10^{51}$ erg; the mass of radioactive nickel is $M_{\rm ^{56}Ni} \approx 0.11$ M⊙, which is completely mixed throughout the ejecta; and the mass of the hydrogen envelope $M_{\rm H\_{env}}$ ≈ 0.06 M⊙. Moreover, SN 2017gpn is a confirmed SN IIb that is located at the farthest distance from the centre of its host galaxy NGC 1343 (i.e. the projected distance is ∼21 kpc). This challenges the scenario of the origin of type IIb supernovae from massive stars.

Aims. The formation process of multiple populations in globular clusters is still up for debate. These populations are characterized by different light-element abundances. Kinematic differences between the populations are particularly interesting in this respect, because they allow us to distinguish between single-epoch formation scenarios and multi-epoch formation scenarios. We derive rotation and dispersion profiles for 25 globular clusters and aim to find kinematic differences between multiple populations in 21 of them to constrain the formation process. Methods. We split red-giant branch (RGB) stars in each cluster into three populations (P1, P2, P3) for the type-II clusters and two populations (P1 and P2) otherwise using Hubble photometry. We derive the global rotation and dispersion profiles for each cluster by using all stars with radial velocity measurements obtained from MUSE spectroscopy. We also derive these profiles for the individual populations of each cluster. Based on the rotation and dispersion profiles, we calculate the rotation strength in terms of ordered-overrandom motion (v/σ) HL evaluated at the half-light radius of the cluster. We then consistently analyse all clusters for differences in the rotation strength of their populations. Results. We detect rotation in all but four clusters.

No abstract

No abstract

Были выполнены наблюдения СН 2017gpn с помощью ПЗСфотометра телескопа Цейсс-1000 (САО РАН) и проведена фотометрия 20 эпох наблюдений. На основе фотометрических данных были построены кривые блеска СН 2017gpn в B-и R-фильтрах. С помощью радиационного гидродинамического кода STELLA было проведено моделирование двухцветной кривой блеска и определены параметры пред-сверхновой звезды. Также мы изучили вопрос исключительного положения СН 2017gpn относительно центра родительской галактики NGC 1343.