93 research outputs found
AGN mass estimates in large spectroscopic surveys: the effect of host galaxy light
Virial-based methods for estimating active supermassive black hole masses are
now commonly used on extremely large spectroscopic quasar catalogues. Most
spectral analyses, though, do not pay enough attention to a detailed continuum
decomposition. To understand how this affects virial mass estimate results, we
test the influence of host galaxy light on them, along with Balmer continuum
component. A detailed fit with the new spectroscopic analysis software QSFit
demonstrated that the presence or absence of continuum components do not affect
significantly the virial-based results for our sample. Taking or not in
consideration a host galaxy component, instead, affects the emission line
fitting in a more pronounced way at lower redshifts, where in fact we observe
dimmer quasars and more visible host galaxies.Comment: 5 pages, 3 figures, accepted for publication on A&
Multiple Depth DB Tables Indexing on the Sphere
Any project dealing with large astronomical datasets should consider the use of a relational database server (RDBS). Queries requiring quick selections on sky regions, objects cross-matching and other high-level data investigations involving sky coordinates could be unfeasible if tables are missing an effective indexing scheme. In this paper we present the Dynamic Index Facility (DIF) software package. By using the HTM and HEALPix sky pixelization schema, it allows a very efficient indexing and management of spherical data stored into MySQL tables. Any table hosting spherical coordinates can be automatically managed by DIF using any number of sky resolutions at the same time. DIF comprises a set of facilities among which SQL callable functions to perform queries on circular and rectangular regions. Moreover, by removing the limitations and difficulties of 2-d data indexing, DIF allows the full exploitation of the RDBS capabilities. Performance tests on Giga-entries tables are reported together with some practical usage of the package
SDAMS: SPOrt Data Archiving and Management System
Abstract. SDAMS is the ensemble of database + software packages aimed to the archiving, quick-look analysis, off-line analysis, network accessibility and plotting of the SPOrt produced data. Many of the aspects related to data archiving, analysis and distribution are common to almost all the astronomical experiments. SDAMS ambition is to face and solve problems like accessibility and portability of the data on any hardware/software platform in a way as simpler as possible, though effective. The system is conceived in a way to be used either by the scientific community interested in background radiation studies or by a wider public with low or null knowledge of the subject. The user authentication system allows us to apply different levels of access, analysis and data retrieving. SDAMS will be accessible through any Web browser though the most efficient way to use it is by writing simple programs. Graphics and images useful for outreach purposes will be produced and put on the Web on a regular basis
La colecistectomia laparoscopica nel paziente uremico
Nel presente studio vengono valutati i vantaggi della colecistectomia
videolaparoscopica (VLC) eseguita in due pazienti uremici affetti da calcolosi
della colecisti.
Dal gennaio al luglio 2004, di 27 pazienti affetti da calcolosi della colecisti 15 sono stati sottoposti a VLC, delle quali 4 sono convertite. Due dei
pazienti sottoposti a VLC erano in trattamento dialitico: una donna di 42
anni, sintomatica, affetta anche da iperparatiroidismo primitivo e da iperaldosteronismo primitivo, e un uomo di 55 anni, asintomatico, in lista per il
trapianto renale. Non sono state osservate complicanze maggiori e minori ed
entrambi i pazienti sono stati dimessi in IV giornata postoperatoria.
Anche nei pazienti uremici la VLC deve essere il gold standard per il
trattamento della calcolosi della colecisti sintomatica o non
The first high-redshift changing-look quasars
We report on three redshift quasars with dramatic changes in their C IV
emission lines, the first sample of changing-look quasars (CLQs) at high
redshift. This is also the first time the changing-look behaviour has been seen
in a high-ionisation emission line. SDSS J1205+3422, J1638+2827, and J2228+2201
show interesting behaviour in their observed optical light curves, and
subsequent spectroscopy shows significant changes in the C IV broad emission
line, with both line collapse and emergence being displayed on rest-frame
timescales of 240-1640 days. These are rapid changes, especially when
considering virial black hole mass estimates of
for all three quasars. Continuum and emission line measurements from the three
quasars show changes in the continuum-equivalent width plane with the CLQs seen
to be on the edge of the full population distribution, and showing indications
of an intrinsic Baldwin effect. We put these observations in context with
recent state-change models, and note that even in their observed low-state, the
C IV CLQs are generally above 5\% in Eddington luminosity.Comment: 12 pages, 7 figures, 4 tables. All data, analysis code and text are
fully available at: github.com/d80b2t/CIV_CLQs. Comments, questions and
suggestions welcome and encourage
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