Related papers: Time-Variable Jet Ejections from RW Aur A, RY Tau …

We present observations of four T Tauri stars using long baseline infrared interferometry from the Palomar Testbed Interferometer. The target sources, T Tau N, SU Aur, RY Tau and DR Tau, are all known to be surrounded by dusty circumstellar…

Classical T Tauri stars show a plethora of in- and outflow signatures in a variety of wavelengths bands. In order to constrain gas velocities and temperatures we analyse the emission in the hot ion lines. We use all available archival FUSE…

Young stars are known to show variability due to non-steady mass accretion rate from their circumstellar disks. Accretion flares can produce strong energetic irradiation and heating that may affect the disk in the planet formation region,…

Aim: The focus of this paper is on two famous but still poorly understood RV Tauri stars: RV Tau and DF Cyg. We aim at confirming their suspected binary nature and deriving their orbital elements to investigate the impact of their orbits on…

We present high resolution optical spectra obtained with the HIRES spectrograph on the Keck I telescope of low mass T Tauri stars and brown dwarfs (LMTTs) in Taurus-Auriga. Of particular interest is the previously classified "continuum T…

We investigate the variability timescales in the jet of M87 with two goals. The first is to use the rise times and decay times in the radio, ultraviolet and X-ray lightcurves of HST-1 to constrain the source size and the energy loss…

The relationship between observed variability time and emission region geometry is explored for the case of emission by relativistic jets. The approximate formula for the jet-frame size of the emission region, $R'=Dc\Delta t_{\rm obs}$ is…

{Abridged version for ArXiv}. We provide direct constraints on the origin of the [Ne II] emission in 15 young stars using high-spatial and spectral resolution observations with VISIR at the VLT that allow us to study the kinematics of the…

We present results from adaptive optics imaging of the T Tauri triple system obtained at the Keck and Gemini Observatories in 2015-2019. We fit the orbital motion of T Tau Sb relative to Sa and model the astrometric motion of their center…

We present a near-IR study of the EXor variable V1118 Ori, performed by following a slightly declining phase after a recent outburst. In particular, the near-IR (0.8 - 2.3 micron) spectrum, obtained for the first time, shows a large variety…

Classical T Tauri Stars (CTTSs) are young, low-mass stars which accrete material from their surrounding protoplanetary disk. To better understand accretion variability, we conducted a multi-epoch, multi-wavelength photometric monitoring…

We present $I$-band time-series photometric variability studies of three known nearby ($\sim$ 140 pc) and young ( $\sim$ 1 Myr) brown dwarfs (BD) in the Taurus star-forming region in the Perseus Molecular Cloud. From 10 nights of…

(Abridged) High-resolution spectroscopic monitoring of RW Aur A was carried out in 1996, 1998 and 1999 with simultaneous B, V photometry. A multicomponent spectrum is revealed with a veiled photospheric spectrum, broad emissions, narrow…

The fine-scale structure and the kinematics of relativistic active galactic nuclei (AGN) jets have been studied by very-long-baseline interferometry at very high resolutions since 1998 at 2 cm wavelength for a sample of over a hundred radio…

We present photometric observations of RW Aurigae, a Classical T Tauri system, that reveal two remarkable dimming events. These events are similar to that which we observed in 2010-2011, which was the first such deep dimming observed in RW…

We analyze ISO/SWS spectra of the RV Tau star R Scuti. The infrared spectra are dominated by H2O emission bands. The near- and mid-infrared excess is attributed to H2O; the dust contribution is less important. We also identify CO, SiO and…

We present simultaneous observations of three recurring jets in EUV and soft X-ray (SXR), which occurred in an active region on 2007 June 5. By comparing their morphological and kinematic characteristics in these two different wavelengths,…

We present the X-ray images of all the available Chandra observations of the galactic jet source SS 433. We have studied the morphology of the X-ray images and inspected the evolution of the arcsec X-ray jets, recently found to be…

We present measurements of the longitudinal magnetic field in the circumstellar environment of seven classical T Tauri stars. The measurements are based on high-resolution circular spectropolarimetry of the He I 5876 emission line, which is…

Spectroscopy of the infrared He I (10830A) line with KECK/NIRSPEC and IRTF/CSHELL, and of the ultraviolet C III (977A) and O VI (1032A) emission with FUSE reveals that the classical T Tauri star TW Hydrae exhibits P Cygni profiles, line…