The near-infrared spectrum of Mrk 1239: direct evidence of the dusty torus?

We report 0.8-4.5 micron SpeX spectroscopy of the narrow-line Seyfert 1 galaxy Mrk1239. The spectrum is outstanding because the nuclear continuum emission in the near-infrared is dominated by a strong bump of emission peaking at 2.2 micron, with a strength not reported before in an AGN. A comparison of the Mrk1239 spectrum to that of Ark564 allowed us to conclude that the continuum is strongly reddened by E(B-V)=0.54. The excess of emission, confirmed by aperture photometry and additional NIR spectroscopy, follows a simple blackbody curve at T=1200 K. This suggest that we may be observing direct evidence of dust heated near to the sublimation temperature, likely produced by the putative torus of the unification model. Although other alternatives are also plausible, the lack of star formation, the strong polarization and low extinction derived for the emission lines support the scenario where the hot dust is located between the narrow line region and the broad line region.Comment: 5 pages, 3 figures. Accepted to MNRAS letter

Hidden starburst in Seyfert 1 Galaxies

We report the detection of the 3.3 mu Polycyclic Aromatic Hydrocarbon (PAH) feature in two Seyfert 1 galaxies - NGC 3227 and Mrk 766, and one QSO - Mrk 478, observed with SpeX at IRTF at a spectral resolution not previously attained for this type of objects. Except for NGC 3227, this is the first time that the 3.3 mu PAH emission is detected in Mrk 766 and Mrk 478. The widths of the emission, reported also for the first time, are rather similar, ranging from 450 A to 550 A. The luminosity of the 3.3 mu PAH emission measured in the QSO Mrk 478 places it at a level similar of that found in starburst and infrared luminous galaxies and implies that this object is having a vigorous burst of star formation. The spatial resolution of the spectra allows us to constrain the location of the star-forming region to the inner 1 Kpc for the QSO and 150 pc for the Seyferts. Our results support the idea that these objects resides in molecular gas-rich galaxies and that their observed infrared excess is primarily due to star formation, as previously indicated by CO and H_2 observations. We also report, for Mrk 1239, the presence of a broad emission feature centred at 3.43 mu, not previosly detected in an extragalactic object and whose origin is not yet clear.Comment: 5 pages, 1 figure. Accepted to MNRAS pink page

Extended Coronal Emission Lines in Active Galactic Nuclei

VLT and NTT spectra are used to examine the nuclear and extended coronal line emission in a sample of well-known Seyfert 1 and 2 galaxies. The excellent spatial resolution obtained with VLT allowed us to map [SiVI] 1.963 $\mu$m and [SiVII] 2.48 $\mu$m on scales of up to 20 pc. Coronal line emission, extended to distances of $\sim$100 pc, is detected in some of the lines analyzed, particularly in [FeX] 6374\AA, [FeXI] 7891\AA, and [SiVII] 2.48$\mu$m. Most coronal lines are strongly asymmetric towards the blue and broader than low-ionization lines. This result is particularly important for Circinus, where previous observations had failed at detecting larger widths for high-ionization lines. Photoionization models are used to investigate the physical conditions and continuum luminosities necessary to produced the observed coronal emission. We found that an ionization parameter U> 0.10 is necessary to reproduce the observations, although the clouds should be located at distances < 30 pc.Comment: 4 pages, 6 figures, to appear in proceedings of IAU Symposium No. 222, The Interplay Among Black Holes, Stars and ISM in Galacti Nucle

Infrared FeII Emission in Narrow-Line Seyfert 1 Galaxies

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 kinematics of the low-ionization broad lines. We found that the 1 micron FeII lines (9997 A, 10501 A, 10863 A and 11126 A) are the strongest FeII lines in the observed interval. For the first time, primary cascade lines of FeII arising from the decay of upper levels pumped by Ly-alpha fluorescence are resolved and identified in active galactic nuclei. Excitation mechanisms leading to the emission of the 1 micron FeII features are discussed. A combination of Ly-alpha fluorescence and collisional excitation are found to be the main contributors. The flux ratio between near-IR FeII lines varies from object to object, in contrast to what is observed in the optical region. A good correlation between the 1 micron and optical FeII emission is found. This suggests that the upper z4Fo and z4Do levels from which the bulk of the optical lines descend are mainly populated by the transitions leading to the 1 micron lines. The width and profile shape of FeII 11127, CaII 8642 and OI 8446 are very similar but significantly narrower than Pa-beta, giving strong observational support to the hypothesis that the region where FeII, CaII and OI are produced are co-spatial, interrelated kinematically and most probably located in the outermost portion of the BLR.Comment: Accepted for publication in ApJ - 35 page

Understanding the two-dimensional ionization structure in luminous infrared galaxies. A near-IR integral field spectroscopy perspective

We investigate the 2D excitation structure of the ISM in a sample of LIRGs and Seyferts using near-IR IFS. This study extends to the near-IR the well-known optical and mid-IR emission line diagnostics used to classify activity in galaxies. Based on the spatially resolved spectroscopy of prototypes, we identify in the [FeII]1.64/Br$\gamma$ - H_2 1-0S(1)/Br$\gamma$ plane regions dominated by the different heating sources, i.e. AGNs, young MS massive stars, and evolved stars i.e. supernovae. The ISM in LIRGs occupy a wide region in the near-IR diagnostic plane from -0.6 to +1.5 and from -1.2 to +0.8 (in log units) for the [FeII]/Br$\gamma$ and H_2/Br$\gamma$ line ratios, respectively. The corresponding median(mode) ratios are +0.18(0.16) and +0.02(-0.04). Seyferts show on average larger values by factors ~2.5 and ~1.4 for the [FeII]/Br$\gamma$ and H_2/Br$\gamma$ ratios, respectively. New areas and relations in the near-IR diagnostic plane are defined for the compact, high surface brightness regions dominated by AGN, young ionizing stars, and SNe explosions, respectively. In addition, the diffuse regions affected by the AGN radiation field cover an area similar to that of Seyferts, but with high values in [FeII]/Br$\gamma$ that are not as extreme. The extended, non-AGN diffuse regions cover a wide area in the diagnostic diagram that overlaps that of individual excitation mechanisms (i.e. AGN, young stars, and SNe), but with its mode value to that of the young SF clumps. This indicates that the excitation conditions of the diffuse ISM are likely due to a mixture of the different ionization sources. The integrated line ratios in LIRGs show higher excitation conditions i.e. towards AGNs, than those measured by the spatially resolved spectroscopy. If this behaviour is representative, it would have clear consequences when classifying high-z, SF galaxies based on their near-IR integrated spectra.Comment: 18 pages, 13 figures, accepted for publication in A&

Multicolor photometry of ten Seyfert 1 galaxies

We present BVI photometry of ten Seyfert 1 galaxies and narrow band H-alpha images for six of these objects as well. The results indicate that the luminosity sample distribution has an amplitude of almost 4 magnitudes with an average of M_B=-20.7. The observed morphologies are confined to early type galaxies. A barred structure is found in only 2 objects. Despite that early morphological types are dominant in this sample, integrated (B-V) colors are very blue. For instance, the SO galaxies show, on average, a (B-V)=0.78. This effect seems to be caused by the luminosity contribution of the active nucleus and/or the disk to the total luminosity of the galaxy. In the B band, the contribution of the active galactic nucleus to the total luminosity of the galaxy varies from 3% to almost 60% and the bulge to disk luminosity ratio (L_bulge/L_disk) ranges from 0.6 to 22. Signs of tidal interactions seems to be a common characteristic since they are observed in 6 of the objects and one of them seems to be located in a poor cluster not yet identified in the literature. H_alpha extended emission is rare, with only 1 galaxy showing clear evidence of it. Luminosity profile decomposition shows that the model Gauss + bulge + disk properly reproduces the surface brightness of the galaxies. However, in order to account for the luminosity profile, most of the disk galaxies needs the inner truncated exponential form with a central cutoff radius ranging from 3 to 10 kpc. This is interpreted in terms of reddened regions that are well identified in the B-V color maps. These regions present very similar colors among them, with (B-V)~1.2. This fact could be associated to the presence of dust confined in the inner regions of the galaxies.Comment: 14 pages, 25 figures. Accepted to Astronomy & Astrophysic

Energy Consumption Analysis Of Machining Centers Using Bayesian Analysis And Genetic Optimization

Responding to the current urgent need for low carbon emissions and high efficiency in manufacturing processes, the relationships between three different machining factors (depth of cut, feed rate, and spindle rate) on power consumption and surface finish (roughness) were analysed by applying a Bayesian seemingly unrelated regressions (SUR) model. For the analysis, an optimization criterion was established and minimized by using an optimization algorithm that combines evolutionary algorithm methods with a derivative-based (quasi-Newton) method to find the optimal conditions for energy consumption that obtains a good surface finish quality. A Bayesian ANOVA was also performed to identify the most important factors in terms of variance explanation of the observed outcomes. The data were obtained from a factorial experimental design performed in two computerized numerical control (CNC) vertical machining centers (Haas UMC-750 and Leadwell V-40iT). Some results from this study show that the feed rate is the most influential factor in power consumption, and the depth of cut is the factor with the stronger influence on roughness values. An optimal operational point is found for the three factors with a predictive error of less than 0.01% and 0.03% for the Leadwell V-40iT machine and the Haas UMC-750 machine, respectively

The OI Line Emission in Active Galactic Nuclei Revisited

UV, visible, and near-infrared spectroscopy is used to study the transitions of neutral oxygen leading to the emission of broad OI $\lambda$8446, $\lambda$11287 and $\lambda$1304 in Active Galactic Nuclei. From the strength of the former two lines, contrary to the general belief, we found that in six out of seven galaxies, L-beta fluorescence is not the only mechanism responsible for the formation of these three lines. Because OI $\lambda$13165 is almost reduced to noise level, continuum fluorescence is ruled out as an additional excitation mechanism, but the presence of OI $\lambda$7774 in one of the objects suggests that collisional ionization may have an important role in the formation of OI $\lambda$8446. The usefulness of the OI lines as a reliable reddening indicator for the broad line region is discussed. The values of E(B-V) derived from the OI $\lambda 1304/\lambda$8446 ratio agree with those obtained using other reddening indicators. The observations point toward a break in the one-to-one photon relation between OI $\lambda$8446 and OI $\lambda$1304, attributable to several destruction mechanisms that may affect the latter line.Comment: 26 pages, 5 figures. Accepted for publication in Ap