Related papers: The EXor phenomenon
We present the results of a comparison between classical and newly identified EXor based on literature data and aimed at recognizing possible differences or similarities of both categories. Optical and near-IR two-color diagrams, modalities…
Eruptive variables are young stars that show episodic variations of brightness: EXors/FUors variations are commonly associated with enhanced accretion outbursts occurring at intermittent cadence of months/years (EXors) and decades/centuries…
Recent years have seen a surge of interest in the community studying the effect of ultraviolet radiation environment, predominantly set by OB stars, on protoplanetary disc evolution and planet formation. This is important because a…
Here we present two of our interesting results obtained over the last 18 months from spectroscopic monitoring of binary pulsating stars and exoplanet host stars. Our investigations are very promising by demonstrating that modern fiber-fed…
The observational evidence for jets and phenomena arising from rotation powered radio pulsars is reviewed, including many recent and exciting discoveries at X-ray wavelengths. The well studied jets of the Crab pulsar are summarised,…
Star-forming regions have been the targets of X-ray observations since the dawn of satellite X-ray astronomy. The increase in sensitivity and/or spatial resolution offered by XMM-Newton and Chandra allows a dramatic improvement, both…
Direct techniques for cosmic ray observations have reached an unprecedented level of precision, unveiling fine-details of the energy spectra. I will introduce the evidence for new spectral features which has been accumulated by new…
Numerous eruptive variable young stellar objects (YSOs), mostly Class I systems, were recently detected by the near-infrared Vista Variables in the Via Lactea (VVV) survey. We present an exploratory near-infrared spectroscopic variability…
V1118 Ori is a classical EXor source whose light curve has been monitored over the past thirty years (although not continuously). It underwent a powerful outburst in 2005, followed by ten years of quiescence and a less intense outburst in…
In recent times, 3.6m Devasthal Optical Telescope (DOT) has installed an optical to near infra-red spectrograph, TANSPEC, which provides spectral coverage from 0.55-2.5 microns. Using TANSPEC, we have obtained a single epoch spectrum of a…
Many X-ray observations of GigaHertz Peaked Spectrum and Compact Steep Spectrum sources have been made with Chandra X-ray Observatory and XMM-Newton Observatory over the last few years. The X-ray spectra contribute the important information…
Recent results are presented and discussed regarding the EUV and X-ray emission of nonmagnetic cataclysmic variables. Emphasis is given to high accretion rate systems (novalike variables and dwarf novae in outburst), and to a number of…
EXor objects are young variables that show episodic variations of brightness commonly associated to enhanced accretion outbursts. With the aim of investigating the long-term photometric behaviour of a few EXor sources, we present here data…
EX Lup is the prototype of the EXor class of eruptive young stars. These objects show optical outbursts which are thought to be related to runaway accretion onto the star. In a previous study we observed in-situ crystal formation in the…
The EXTraS project (Exploring the X-ray Transient and variable Sky) will harvest the hitherto unexplored temporal domain information buried in the serendipitous data collected by the European Photon Imaging Camera (EPIC) instrument onboard…
The occurrence of successive extreme observations can have an impact on society. In extreme value theory there are parameters to evaluate the effect of clustering of high values, such as the extremal index. The estimation of the extremal…
The outbursts of novae are among the strongest explosions in the Universe. The eruptions involve physical processes that span the whole electromagnetic spectrum, demanding multifrequency observations. The photometric and spectroscopic…
In early 2008, the young low-mass star EX Lupi, the prototype of the EXor class of eruptive variables, optically brightened by over five magnitudes for a period of 7 months. The previous time a change of such amplitude had been observed in…
In recent years, blazar surveys at radio and X-ray energies have greatly increased our understanding of this type of active galaxy. The combination of multi-wavelength data has shown that blazars follow a well defined sequence in terms of…
The recent detections of microquasars at energies above a few hundred keV up to the TeV in one case has stimulated a strong interest and raised several questions. How are the MeV, GeV, and even TeV emissions, produced? What are the emission…