Estudio de los reportes de las infecciones respiratorias agudas

Despite the deeper NIRI images (average seeing of0.33arcsecs(at worst

0.43arcsecs) using a pixel scale of0.12arcsecs, i.e. a factor of 3-4 better than the average SDSS images (ground-based seeing of typically1.5arcsecsand pixel scale of0._{4arcsecs)), the greatest uncertainty is that associated with not being able to}

resolve the bulge, or, adequately identify a galaxy as bulge-less. Bulge-less galaxies exist (see e.g.Simmons et al.,2013), and being able to accurately identify these is crucial in order to correctly infer the BH mass-host-galaxy-relations. It is

therefore necessary to develop a well-defined means, e.g. a criteria on the derived host-galaxy parameters, to help determine whether a bulge is present.

Pseudo-bulges are, in general relatively, small (compared to classical-bulges) inner disk-like structures (see e.g.Gadotti,2009), typically found in galaxies with developed bars. Due to these properties pseudo-bulges are by their nature harder to resolve and distinguish from the bright PSF than classical-bulges. This makes it harder to accurately estimate their parameters and thus their luminosities, and subsequently to determine whether pseudo-bulges are on or off the scaling relations, which is a key factor in our understanding of the BH scaling relations (as discussed in section 1.1.3). In this study we considered any bulge with effective radiusre,B <2as unresolved, unless the bulge had extended wings that

made the model parameters reliable. This caused us to conclude that 4 of the 15 host-galaxies had unresolved bulges or suffered from significant PSF-mismatches that made our measurements unreliable. For these objects we could only

determine an upper limit for the bulge luminosity. However, given our results, we see that the upper bulge luminosities for the galaxies lie in the very same region as those for the bulges that are clearly resolved. We could therefore argue that despitereB <2, the result may still be reliable. Assuming this is the case,

according to figure 4.1.1, one can conclude that pseudo-bulges are on the relations as much as are classical-bulges.

The most obvious path towards resolving small bulges and distinguishing them from the bright AGN is to increase image spatial-resolution even further. This could help determine whether our derived parameters, especially for host-galaxies whose models suffer suspected PSF mismatches or unresolved bulges, are accurate. This would in particular favor proper identification of pseudo-bulges. Provided our images have a FWHM of approximately0.3arcsec, the image quality is one of the best obtainable using earth-based telescopes. The next step forward is therefore to use space based telescopes. A Cycle 25 SNAP Proposal for the Hubble Space Telescope, aimed at imaging 84 galaxies (resulting in approximately30target images based on a normal SNAP success rate) from the parent sample (seeBennert et al.,2015) to obtain high-resolution data was

therefore submitted (April 2017) and accepted ( June 2017). The HST started obtaining data in October 2017 and Cycle 25 will continue until September 2018. Granted time with the Hubble Space Telescope, we will be provided unique data of unsurpassed quality. In a future project this data will be analyzed and used to help constrain the BH mass-luminosity scaling relations and include more certain measurements of pseudo-bulges allowed by the improved image resolution.

Another issue with our model accuracy is associated with improperly representing the PSF. Despite our attempts to model the AGN as accurately as possible with an image of a star, carefully selected to minimize systematic errors, this PSF-image is likely one of our biggest sources of error. Ideally the PSF-image should be one of infinite signal-to-noise ratio. In this case Galfit would not reject or underestimate the PSF-component because of noise in the wings which if amplified would cause theχ2_νto increase. In any future study an alternative approach may be to replace the PSF-images with model images of the PSF-images, i.e. the model image produced by letting Galfit fit a model containing Sérsic components to the PSF-image of a star. This would remove issues with signal-to-noise ratios, but might on the other hand introduce issues associated with producing PSF-images that do not account for asymmetric features present in the the true PSF. This method could however be standardized, allowing for a systematic and well-defined approach that could potentially be easier to analyze statistically.

Finally, we wish to point out that our host galaxies seem to be over-luminous. The principal difference between our sample and that ofLäsker et al.(2014a,b) is that our galaxies are active, whereas theirs are quiescent. Thus, our data suggest that active galaxies constitute a sub-sample of relatively more massive/luminous galaxies compared to quiescent galaxies. This observation is supported by the recent studyLäsker et al.(2016) in which a similar observation is made when studying megamasers. They exploit HST images of nine megamaser disk galaxies. Megamaser disks allow for precise BH mass measurements, which combined with decomposition of high-resolution HST images results in accurate BH mass - host galaxy scaling relations. Their findings are shown in figure 4.2.1 which is

excerpted from that paper. Our results are also in agreement with findings to be presented in a future paper Bennert et al. 2017 in which the full parent sample of host galaxies, based on the SDSS images, is found to be over-luminous.