Search

The interaction between Active Galactic Nuclei (AGN) and their host galaxies is scarcely resolved. Narrow-line Seyfert 1 (NLS1) galaxies are believed to represent AGN at early stages of their evolution and allow to observe AGN feeding and feedback processes at high accretion rates. We apply a spectroastrometric analysis to VLT MUSE NFM-AO observations of Mrk 1044, a nearby super-Eddington accreting NLS1. This allows us to map two ionised gas outflows traced by [O$\,$III] which have velocities of $-560\pm20\,{\rm km\:s}^{-1}$ and $-144 \pm 5 \,{\rm km\:s}^{-1}$. Both outflows are spatially unresolved and located close to the galaxy nucleus ($, 17 pages. 12 figures. Re-submitted to A&A after minor revision. Comments welcome

We present IRAM-30m Telescope $^{12}$CO and $^{13}$CO observations of a sample of 55 luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) in the local universe. This sample is a subset of the Great Observatory All-Sky LIRG Survey (GOALS), for which we use ancillary multi-wavelength data to better understand their interstellar medium and star formation properties. Fifty-three (96%) of the galaxies are detected in $^{12}$CO, and 29 (52%) are also detected in $^{13}$CO above a 3$\sigma$ level. The median full width at zero intensity (FWZI) velocity of the CO line emission is 661km s$^{-1}$, and $\sim$54% of the galaxies show a multi-peak CO profile. Herschel photometric data is used to construct the far-IR spectral energy distribution of each galaxy, which are fit with a modified blackbody model that allows us to derive dust temperatures and masses, and infrared luminosities. We make the assumption that the gas-to-dust mass ratio of (U)LIRGs is comparable to local spiral galaxies with a similar stellar mass (i.e., gas/dust of mergers is comparable to their progenitors) to derive a CO-to-H$_2$ conversion factor of $\langle\alpha\rangle=1.8^{+1.3}_{-0.8}M_\odot$(K km s$^{-1}$pc$^{2}$)$^{-1}$; such a value is comparable to that derived for (U)LIRGs based on dynamical mass arguments. We derive gas depletion times of $400-600$Myr for the (U)LIRGs, compared to the 1.3Gyr for local spiral galaxies. Finally, we re-examine the relationship between the $^{12}$CO/$^{13}$CO ratio and dust temperature, confirming a transition to elevated ratios in warmer systems., Comment: 32 pages, 10 figures. Accepted for publication in Astronomy & Astrophysics

"The centimeter spectra of Wolf-Rayet (WR) binaries often sh ow a contribu- tion from a wind-wind collision region (WCR) between the sta rs. In short period systems ( ∼ < 1 yr), such a component is expected to be absorbed by the unsho cked winds, losing any effect from its binarity. Recent studies su ggest that the WCR in these systems may also contribute to the emission at both cen timeter and millimeter wavelengths. We analyzed and compared centimeter and milli meter observations of a total sample of 17 WR stars (including nine confirmed shor t-period systems) to detect any possible WCR contribution. More detailed obse rvations are required in order to distinguish between different scenarios. We high light the importance of analyzing the spectrum from quasi-simultaneous observa tions in a wide range of frequencies in order to properly characterize and distin guish any possible extra contribution."

To determine the incidence of outcomes, unanticipated admissions and cancellations in patients operated in an Ambulatory surgery unit, and to establish the relationships with their body mass index (BMI).An observational descriptive prospective study was conducted in the Ambulatory surgery unit of the University Hospital Virgen del Rocío of Seville, on ASA I or II adult patients proposed for day case surgery with loco-regional or general anesthesia. A cohort of 1,088 patients was classified according to their body mass index into four groups: no obesity (BMI30), obesity i (BMI 30-34.9), obesity ii (BMI 35-39.9), and morbid obesity iii (BMI 40-49.9). Postoperative outcomes (48h), inpatient admissions, and cancellations where calculated.The obesity ii (BMI 35-39.9) group showed a higher incidence of postoperative complications (7.69%), unplanned admissions (7.69%), and surgical cancellations (4.87%), doubling, at least, the incidence of adverse events of the other study groups, even when no significant difference was found. Outcomes where similar in all study groups.The results of this study suggest that moderate and severe obesity should be a risk factor for postoperative complications, unplanned admissions, and cancellations in outpatient surgery. Adequate patient selection and preoperative evaluation, as well as strategies for the prevention and control of the most frequents complications in obese patients are the key factors for their integration in major ambulatory surgery programs.

"We present a semi-analytic model for computing the thermal radio continuum emission from radiative shocks within colliding wind binaries. Assuming a thin shell approximation, we calculate the contribution of the wind collision region (WCR) to the total thermal emission for close binaries. We investigate the effect of the binary separation on the total spectrum. In addition, we point out the relevance of taking into account this contribution for the correct interpretation of the observations, and the accuracy of parameters derived from them."

The nearby dwarf spheroidal galaxy Draco with its high mass to light ratio is one of the most auspicious targets for indirect dark matter searches. Annihilation of hypothetical DM particles can result in high-energy gamma-rays, e.g. from neutralino annihilation in the supersymmetric framework. With the MAGIC telescope a search for a possible DM signal originating from Draco was performed during 2007. The analysis of the data results in a flux upper limit of 1.1x10^-11 photons cm^-2 sec^-1 for photon energies above 140 GeV, assuming a point like source. Furthermore, a comparison with predictions from supersymmetric models is given. While our results do not constrain the mSUGRA phase parameter space, a very high flux enhancement can be ruled out., Comment: Accepted for publication by Astrophysical Journal

We present high-resolution observations of the supernova SN1986J in the galaxy NGC891 at the frequency of 5 GHz, more than 15 years after its explosion. The image shows a highly distorted shell of radio emission, suggesting that the shock front has been strongly deformed. The brightness distribution within the shell is also highly asymmetric, and we propose that such asymmetry could be due to the collision of the supernova ejecta with an anisotropic, clumpy medium. The average speed of the shell has decreased from about 7400 km s−1 in 1988.74 down to ~ 6300 km s−1 in 1999.14, pointing to a mild deceleration in the expansion of SN 1986J. Assuming a standard density profile for the progenitor wind, we infer a swept-up mass by the shock front of ≈ 2.2 M⊙. Since the supernova has not yet suffered a strong deceleration, momentum conservation arguments point to a mass of the hydrogen-rich envelope ejected at explosion as large as ~ 12 M⊙.

We present continuum VLA measurements of SN1993J in M81 taken on 17 and 21 December 2000, about 2820 days after the supernova explosion, spanning the frequency range from 0.32 to 14.9 GHz. These observations aimed at discerning the main absorbing processes acting in SN1993J at late epochs. We discuss three models for the late radio emission of SN1993J: (i) a simple power-law spectrum, (ii) a power-law spectrum free-free absorbed by a screen of homogeneously distributed ionized gas, and (iii) a power-law spectrum free-free absorbed by a “clumpy” medium. We find that the best fit to the data is yielded by a power-law spectrum free-free absorbed by either a homogeneous, or a clumpy, distribution of ionized gas. The radio spectrum between 0.32 and 14.9 GHz is well characterized by α = −0.67 ± 0.02 (Sv α vα), typical of an optically thin radio supernova, and is significantly different from that obtained at epochs ≲1000 days between 1.4 and 14.9 GHz, which indicates an ongoing spectral evolution in the radio emission from SN1993J. Since the spectral index γ of the electron distribution (N E = NoE −γ), is related to the observed spectral index by γ = 1–2 α, our value of α translates into γ = 2.34 ± 0.04, which agrees with that predicted by Fransson & Bjornsson (1998, ApJ, 509, 861) for t ≳ 1000 days. We also fit the available radio continuum data of SN1993J for the period from ∼ 70 up to 2820 days since the explosion, using a power-law spectrum free-free absorbed by a screen of homogeneously distributed ionized gas. The fit shows that the observed spectral index of SN1993J has been slowly evolving since t ∼ 1000 days on, with α increasing from a value close to −1 to −0.67. This spectral evolution seems to suggest that, in addition to the radiative (synchrotron) losses, adiabatic cooling and ionization (Coulomb) losses at the lowest frequencies might be contributing significantly to the integrated electron spectrum.

We present wide-field images of the quadruple gravitational lenses B 1422+231 and MG J0414+0534 obtained from global Very Long Baseline Interferometry (VLBI) observations at 8.4 GHz on 23rd November 1997. We present also a lens model for MG J0414+0534, which reproduces the core positions and flux densities of the VLBI images, combining a singular isothermal ellipsoid with external shear, and a singular isothermal sphere to represent, respectively, the main lens galaxy and its neighbor, a faint galaxy near one of the images.

The standard interaction model (SIM) for radio supernovae considers the synchrotron radio emission to arise in a shell optically thin to its own radio emission, and to be partially absorbed due to ionized thermal electrons in the circumstellar wind of the progenitor star. Although such model has been successful in interpreting the light curves of several radio supernovae, it has been suggested that synchrotron self-absorption could play a relevant role for some of them.

The standard model for radio supernovae considers the synchrotron radio emission to be only partially absorbed by ionized thermal electrons in the circumstellar wind of the progenitor star. However, for the best studied radio supernova, SN 1993J, we present evidence of synchrotron self-absorption based on modelfits to all available radio data. We show that while external absorption is the main absorption mechanism at early times, synchrotron self-absorption is the dominant mechanism at late epochs.