arXiv subjects

J. León-Tavares

Publications and source records attributed to J. León-Tavares.

21 records · Page 2Linked to original sources

arXiv2010

Multi-band properties of superluminal AGN detected by Fermi/LAT

We perform a multi-band statistical analysis of core-dominated superluminal active galactic nuclei (AGN) detected with Fermi Large Area Telescope (LAT). The detection rate of $γ$-ray jets is found to be high for optically bright AGN. There is a significant correlation between the $γ$-ray luminosity and the optical nuclear and radio (15 GHz) luminosities of AGN. We report a well defined positive correlation between the $γ$-ray luminosity and the radio-loudness for quasars and BL Lacertae type objects (BL Lacs). The slope of the best-fit line is significantly different for quasars and BL Lacs. The relations between the optical and radio luminosities and the $γ$-ray loudness are also examined, showing a different behavior for the populations of quasars and BL Lacs. Statistical results suggest that the $γ$-ray, optical and radio emission is generated at different locations and velocity regimes along the parsec-scale jet.

astro-ph.CO↗

arXiv2010

Spectral optical monitoring of 3C390.3 in 1995-2007: I. Light curves and flux variation of the continuum and broad lines

Here we present the results of the long-term (1995-2007) spectral monitoring of the broad line radio galaxy \object{3C~390.3}, a well known AGN with the double peaked broad emission lines, usually assumed to be emitted from an accretion disk. To explore dimensions and structure of the BLR, we analyze the light curves of the broad H$α$ and H$β$ line fluxes and the continuum flux. In order to find changes in the BLR, we analyze the H$α$ and H$β$ line profiles, as well as the change in the line profiles during the monitoring period. First we try to find a periodicity in the continuum and H$β$ light curves, finding that there is a good chance for quasi-periodical oscillations. Using the line shapes and their characteristics (as e.g. peaks separation and their intensity ratio, or FWHM) of broad H$β$ and H$α$ lines, we discuss the structure of the BLR. Also, we cross-correlate the continuum flux with H$β$ and H$α$ lines to find dimensions of the BLR. We found that during the monitoring period the broad emission component of the H$α$ and H$β$ lines, and the continuum flux varied by a factor of $\approx $4-5. Also, we detected different structure in the line profiles of H$α$ and H$β$. It seems that an additional central component is present and superposed to the disk emission. In the period of high activity (after 2002), H$β$ became broader than H$α$ and red wing of H$β$ was higher than the one of H$α$. We found time lags of $\sim$95 days between the continuum and H$β$ flux, and about 120 days between the continuum and H$α$ flux. Variation in the line profiles, as well as correlation between the line and continuum flux during the monitoring period is in the favor of the disk origin of the broad lines with the possible contribution of some additional region and/or some kind of perturbation in the disk.

astro-ph.GA↗

arXiv2009

The Expanding Nebular Remnant of the Recurrent Nova RS Ophiuchi (2006): II. Modeling of Combined Hubble Space Telescope Imaging and Ground-based Spectroscopy

We report Hubble Space Telescope imaging, obtained 155 and 449 days after the 2006 outburst of the recurrent nova RS Ophiuchi, together with ground-based spectroscopic observations, obtained from the Observatorio Astronómico Nacional en San Pedro Mártir, Baja California, México and at the Observatorio Astrofísico Guillermo Haro, at Cananea, Sonora, México. The observations at the first epoch were used as inputs to model the geometry and kinematic structure of the evolving RS Oph nebular remnant. We find that the modeled remnant comprises two distinct co-aligned bipolar components; a low-velocity, high-density innermost (hour glass) region and a more extended, high-velocity (dumbbell) structure. This overall structure is in agreement with that deduced from radio observations and optical interferometry at earlier epochs. We find that the asymmetry observed in the west lobe is an instrumental effect caused by the profile of the HST filter and hence demonstrate that this lobe is approaching the observer. We then conclude that the system has an inclination to the line of sight of 39$^{+1}_{-10}$ degrees. This is in agreement with the inclination of the binary orbit and lends support to the proposal that this morphology is due to the interaction of the outburst ejecta with either an accretion disk around the central white dwarf and/or a pre-existing red giant wind that is significantly denser in the equatorial regions of the binary than at the poles. The second epoch HST observation was also modeled. However, as no spectra were taken at this epoch, it is more difficult to constrain any model. Nevertheless, we demonstrate that between the two HST epochs the outer dumbbell structure seems to have expanded linearly.

astro-ph.SR↗