Related papers: Accretion and outflow activity in proto-brown dwar…

Very high resolution (R~160,000-210,000), high signal-to-noise ratio (S/N>300) spectra of nine bright K-dwarfs were obtained with the 2dcoude spectrograph on the 2.7m Telescope at McDonald Observatory to determine wavelength shifts and…

Jets around low- and intermediate-mass young stellar objects (YSOs) contain a fossil record of the recent accretion and outflow activity of their parent star-forming systems. We aim to understand whether the accretion/ejection process is…

This work aims to derive accretion rates for a sample of 38 HAeBe stars. We apply magnetospheric accretion (MA) shock modelling to reproduce the observed Balmer excesses. We look for possible correlations with the strength of the Halpha,…

Using SpeX at the NASA Infrared Telescope Facility and the Spitzer Infrared Spectrograph, we have obtained infrared spectra from 0.7 to 30um for three young brown dwarfs in the TW Hydra Association (~10 Myr), 2M J1207-3932, 2M J1139-3159,…

We obtained 0.8-2.4 micron spectra at a resolution of 320 km/s of four narrow-line Seyfert 1 galaxies in order to study the near-infrared properties of these objects. We focus on the analysis of the FeII emission in that region and the…

Low-mass pre-main sequence (PMS) stars are strong X-ray sources, because they possess hot corona like their older main-sequence counterparts. Unique to young stars, however, are X-rays from accretion and outflows, and both processes are of…

The inner regions of protoplanetary disks are the locations where most of planets are thought to form and where processes that influence the global evolution of the disk, such as MHD-winds and photoevaporation, originate. Transition disks…

Echelle spectroscopy of H2, [FeII] and Br-gamma line emission from a very young planetary nebula, IRAS 21282+5050, and from four proto-planetary nebulae, IRAS 19343+2926 (M 1-92), IRAS 17150-3224 (AFGL 6815), IRAS 17423-1755 (Hen 3-1475),…

We discover that the very low-mass brown dwarf OTS44 (M9.5, ~12 M_Jup) has significant accretion and a substantial disk, which demonstrates that the processes that accompany canonical star formation occur down to a central mass of a few…

Young stars and planetary systems form in molecular clouds. For classical T Tauri stars (CTTS, F-K type precursors) the accretion disk does not reach down to the central star, but it is truncated near the co-rotation radius. The inner edge…

Fanaroff-Riley II low-excitation radio galaxies (FRII-LERGs) are characterized by weak nuclear excitation on pc-scales and by properties typical of powerful FRIIs (defined as high-excitation, hereafter HERGs/BLRGs) on kp-scales. Since a…

Short abstract: We present fully 3-D simulations of supersonic, radiatively cooling intermittent jets with intermediate and long variability periods (that is, periods of the order of or longer than, the dynamical time scale of the jet).…

X-ray absorption line spectroscopy has recently shown evidence for previously unknown Ultra-fast Outflows (UFOs) in radio-quiet AGNs. In the previous paper of this series we defined UFOs as those absorbers with an outflow velocity higher…

We present proper motion measurements of 37 jets and HH objects in the Carina Nebula measured in two epochs of H$\alpha$ images obtained $\sim 10$ yrs apart with HST/ACS. Transverse velocities in all but one jet are faster than $\gtrsim 25$…

We present optical spectroscopy of EX Hya during its 1991 outburst. This outburst is characterised by strong irradiation of the front face of the secondary star by the white dwarf, an overflowing stream which is seen strongly in HeII and by…

We have followed up on our observations of the ~ 40-Myr, and still accreting, PMC Delorme 1 (AB)b. We used high-resolution spectroscopy to characterise the accretion process further by accessing the wealth of emission lines in the near-UV.…

We present continued analysis of a sample of low-redshift iron low-ionization broad absorption-line quasars (FeLoBALQs). Choi et al. (2022) presented $SimBAL$ spectral analysis of BAL outflows in 50 objects. Leighly et al. (2022) analyzed…

Investigating the outflows emanating from young stellar objects (YSOs) on sub-arcsecond scales provides important clues to the nature of the underlying accretion-ejection process occurring near the central protostar. We have investigated…

As part of a multi-faceted program to investigate the origin and early evolution of sub-stellar objects, we present high-resolution Keck optical spectra of 14 very low mass sources in the IC 348 young cluster and the Taurus star-forming…

In this paper, we establish and calibrate mid-infrared hydrogen recombination lines observed with JWST as accretion tracers for pre-main-sequence stars that accrete from circumstellar disks. This work is part of a coordinated,…