相关论文: ate helium flash in V605 Aql: PNe evolution and sh…

I review the current status of our theoretical understanding of Pulsar Winds and associated nebulae (PWNe). In recent years, axisymmetric models of pulsar winds with a latitude dependent energy flux have proved very successful at explaining…

Shell galaxies are considered the debris of recent accretion/merging episodes. Their high frequency in low density environments suggest that such episodes could drive the secular evolution for at least some fraction of the early-type galaxy…

We present a search for rings or arcs in the haloes of planetary nebulae (PNe). We discovered such structures in eight PNe, tripling the sample of PNe with known rings. This shows that, contrary to what was believed to date, the occurrence…

The most numerous source class that emerged from the H.E.S.S. Galactic Plane Survey are Pulsar Wind Nebulae (PWNe). The 2013 reanalysis of this survey, undertaken after almost 10 years of observations, provides us with the most sensitive…

Planetary nebulae (PNe) shown to be members of star clusters provide information on their properties and evolutionary histories that cannot be determined for PNe in the field, in particular the initial masses of their progenitor stars. Here…

In a Pulsar Wind Nebula (PWN), the lifetime of inverse Compton emitting electrons exceeds the lifetime of its progenitor pulsar, but it exceeds also the age of the electrons that emit via synchrotron radiation; i.e. during the evolution of…

We investigate the velocity structure of nebular gas in the central galaxies of four clusters: Abell 1835, PKS 0745-191, Abell 262, and RXJ0820.9+0752, using data from the Keck Cosmic Web Imager (KCWI). Velocity structure functions (VSFs)…

Nova shells are the remnants of a nova eruption in a cataclysmic variable system. By studying their geometry we can better understand the physical mechanisms that shape them during the nova eruption. A nova shell that challenges our current…

We explore different evolutionary scenarios to explain the helium deficiency observed in H1504+65, the most massive known PG1159 star. We concentrate mainly on the possibility that this star could be the result of mass loss shortly after…

High resolution ALMA observations of the recent (2.52 yrs old) shell of Nova V5668 Sgr (2015) show a highly structured ionised gas distribution with small (10$^{15}$ cm) clumps. These are the smallest structures ever observed in the remnant…

We report new Chandra X-ray observations of the shell supernova remnant (SNR) Kes 75 (G29.7-0.3) containing a pulsar and pulsar-wind nebula (PWN). Expansion of the PWN is apparent across the four epochs, 2000, 2006, 2009, and 2016. We find…

A classical nova is an eruption on the surface of a white dwarf in an accreting binary system. The material ejected from the white dwarf surface generally forms an axisymmetric shell. The shaping mechanisms of nova shells are probes of the…

CO(J = 2-1) and SiO(J = 5-4) emission has been observed from the molecular envelope around the nearby S star pi Gru. The CO line profile differs from the usual parabolic shape seen in uniformly expanding envelopes; it has a Voigt-like…

Pulsars are rapidly-rotating neutron stars born out of the death of stars. A diffuse nebula is formed when particles stream from these neutron stars and interact with the ambient medium. These pulsar wind nebulae (PWNe) are visible across…

The results of a NLTE model atmosphere analysis of 27 hydrogen-rich central stars of old planetary nebulae (PN) are reported. These stars were selected from a previous paper in this series, where we gave classifications for a total of 38…

Diffuse X-ray emission has been detected in a small number of planetary nebulae (PNe), indicating the existence of shocked fast stellar winds and providing support for the interacting-stellar-winds formation scenario of PNe. However, the…

We show that the termination of the star formation process by winds from massive stars in protocluster forming clumps imposes dual constraints on the star formation efficiencies (SFEs) and stellar age spreads ($\Delta \tau_{*}$) in stellar…

The New Horizons spacecraft's encounter with the cold classical Kuiper belt object (486958) Arrokoth (formerly 2014 MU69) revealed a contact-binary planetesimal. We investigate how it formed, finding it is the product of a gentle, low-speed…

The well known Crab Nebula is at the center of the SN1054 supernova remnant. It consists of a rotationally-powered pulsar interacting with a surrounding nebula through a relativistic particle wind. The emissions originating from the pulsar…

We present a $0.8-2.5\,\mu$m spectrum of the Very Late Thermal Pulse object V4334 Sgr (Sakurai's Object), obtained in 2020 September. The spectrum displays a continuum that rises strongly to longer wavelengths, and is considerably brighter…