Searching for Debris Disks around Isolated Pulsars
Zhongxiang Wang
备注：
23 pages, 3 figures, based on an invited talk at the Cosmic Dust VI conference, significant comments from referees incorporated, accepted for publication in Planetary and Space Science
Different pieces of observational evidence suggest the existence of disks around isolated neutron stars. Such disks could be formed from supernova fallback when neutron stars are born in core-collapse supernova explosions. Efforts have been made to search for disks around different classes of pulsars, which include millisecond pulsars, young neutron star classes (magnetars, central compact objects, and X-ray dim isolated neutron stars), and regular radio pulsars. We review the main results from observations at wavelengths of from optical to sub-millimeter/millimeter.
HD49798/RX J0648.0-4418 is a peculiar binary including a hot subdwarf of O spectral type and a compact companion in a 1.55 day orbit. According to the steady spin period derivative $\dot{P}=(-2.17\pm0.01)\times10^{-15} ~\rm s\,s^{-1}$ , the compact object was thought to be a contracting young white dwarf (WD). However, the X-ray luminosity producing by the wind accretion of massive WD is one order of magnitude smaller than the observed value. In this work, we propose an alternative model to account for the observed X-ray luminosity. If the WD was surrounded by a debris disk, the accretion from…
Context: Debris discs orbiting young stars are key to understand dust evolution and the planetary formation process. We take advantage of a recent membership analysis of the 30 Myr nearby open cluster IC 4665 based on the Gaia and DANCe surveys to revisit the disc population of this cluster. Aims: We aim to study the disc population of IC 4665 using Spitzer (MIPS and IRAC) and WISE photometry. Methods: We use several colour-colour diagrams with empirical photospheric sequences to detect the sources with an infrared excess. Independently, we also fit the spectral energy distribution (SED) of ou…
Searching for Spider-Like Pulsars from TESS Ellipsoidal Lightcurves with X-ray counterparts
School of Physics and Astronomy, Sun Yat-Sen University（中山大学物理学院）；CSST Science Center for the Guangdong-Hongkong-Macau Greater Bay Area, Sun Yat-Sen University（中山大学CSST粤港澳大湾区科学中心）；Laboratory for Space Research, The University of Hong Kong（香港大学空间研究实验室）；Institute of Astronomy Space and Earth Science, P177, CIT Road, Scheme-7M, Kolkata, 700054, West Bengal, India（印度西孟加拉邦加尔各答CIT路P177号 scheme-7M 天体物理学、空间与地球科学研究所）
The nature of the few known solar-mass stars simultaneously containing debris disks and planets remains an open question. A number of works have shown that this property appears to be independent of planetary masses as well as of stellar age, but possible correlations with stellar kinematics and metallicity have not been investigated. In this paper, we show that the majority of known stars containing both debris disks and planets belong to the metal-enriched Galactic thin disk. The few exceptions are stars that seem to be born in the star formation peak occurring in times of thick disk formati…
Discovering radio pulsars, particularly millisecond pulsars (MSPs), is important for a range of astrophysical applications, such as testing theories of gravity or probing the magneto-ionic interstellar medium. We aim to discover pulsars that may have been missed in previous pulsar searches by leveraging known pulsar observables (primarily polarisation) in the sensitive, low-frequency radio images from the Low-Frequency Array (LOFAR) Two-metre Sky Survey (LoTSS), and have commenced the Targeted search, using LoTSS images, for polarised pulsars (TULIPP) survey. For this survey, we identified lin…
Observing and timing a group of millisecond pulsars (MSPs) with high rotational stability enables the direct detection of gravitational waves (GWs). The GW signals can be identified from the spatial correlations encoded in the times-of-arrival of widely spaced pulsar-pairs. The Chinese Pulsar Timing Array (CPTA) is a collaboration aiming at the direct GW detection with observations carried out using Chinese radio telescopes. This short article serves as a `table of contents' for a forthcoming series of papers related to the CPTA Data Release 1 (CPTA DR1) which uses observations from the Five-h…
Debris disks around stars are considered as components of planetary systems. Constrain the dust properties of these disks can give crucial information to formation and evolution of planetary systems. As an all-sky survey, \textit{InfRared Astronomical Satellite} (\iras) gave great contribution to the debris disk searching which discovered the first debris disk host star (Vega). The \iras-detected debris disk sample published by Rhee \citep{rhe07} contains 146 stars with detailed information of dust properties. While the dust properties of 45 of them still can not be determined due to the limit…
Planets and their host stars carry a long-term memory of their origin in their chemical compositions. Thus, identifying planets formed in different environments improves our understating of planetary formation. Although restricted to detecting exoplanets within the solar vicinity, we might be able to detect planetary systems that formed in small external galaxies and later merged with the Milky Way. In fact, Gaia data have unequivocally shown that the Galaxy underwent several significant minor mergers during its first billion years of formation. The stellar debris of one of these mergers, Gaia…
The co-existence of hot and cold gas in debris discs
碎片盘经常被描述为贫气盘，因为气体与尘埃的比率预计要比原始的原行星盘低得多。然而，最近的观测证实，在年轻的主序星周围的星周碎片盘中存在着不可忽略的冷气体，这种冷气体被认为与微行星和类彗星天体的脱气有关。该文件的目的是调查在周围的恒星轴承冷气碎片盘的热气的存在。除了$β$ Pic和北落师门外，我们已经从不同的天文台获得了所有目前已知的含冷气的碎片盘系统的高分辨率光谱，我们分析了Ca II H & K和Na I D线，寻找通常归因于类彗星活动的CS起源的非光球层反射。狭窄的，稳定的钙II和/或钠I吸收功能已被检测到叠加到光球线在10个观察到的15个冷气体轴承碎片disption.Features被发现在恒星的径向速度，或略有蓝移或红移，和/或在当地的星际介质（ISM）的速度。有些恒星也呈现出向红色波长延伸的瞬变事件或反射。这是第一次在15颗观测到的恒星中的7颗中检测到这种Ca II特征。在这些恒星中的一些，结果表明，稳定和可变的反射来自相对较热的气体位于CS接近环境。这种热气体被检测到在至少~ 80%，边缘上的冷气轴承碎片光盘，而在只有~10%的光盘看到接近face-on. We解释这是一个几何效应，并建议，未检测到热气体的反射是由于光盘的倾斜，而不是没有热气体成分。
