We report the discovery of peculiar features in the optical spectrum of
4C+22.25, a flat spectrum radio quasar at z=0.4183 observed in the SDSS
and in a dedicated spectroscopic follow-up from the Nordic Optical
Telescope. The Hbeta and Halpha lines show broad profiles (FWHM~12,000
km/s), faint fluxes and extreme offsets (Delta v=8,700+/-1,300 km/s)
with respect to the narrow emission lines. These features show no
significant variation in a time lag of ~3.1 yr (rest frame). We rule out
possible interpretations based on the superposition of two sources or on
recoiling black holes, and...
Radial velocity studies have provided the majority of all exoplanet
discoveries. Using the radial velocity techniques on young stars suffers
from problems with magnetic activity jitter, which has been studied for
years, and the effects of circumstellar disks, which has remained
unstudied. Here we study the disk-embedded star BP Psc using high
resolution, high accuracy HARPS spectra. We derive radial velocities,
activity indices, and line profile information. We find that the
presence of a disk severely limits information about the star. We find
that even the line profiles are...
We present time-resolved V photometry of the old nova RRPictoris
(RRPic). Apart from the hump-like variability, the light curves show the
strong flickering and random variation typical for RRPic. We do not find
any convincing evidence for the previously reported eclipse. The
extrapolated eclipse phase coincides with a broad minimum, but comparing
the overall shape of the light curve suggests that the eclipse should
actually be located around phase 0.2. The orbital period which we derive
from these data agrees well with the old one, any uncertainty is too
small to account for the...
ara.roma.it utilizza cookie tecnici necessari al funzionamento del sito e, previo consenso, cookie di terze parti (es. video YouTube, meteo).
Cookie Policy
