We present a method for knowledge analysis in large astronomical spectrophotometric archives. The method is based on a type of unsupervised learning Artificial Neural Networks named Self-organizing maps (SOMs). SOMs are used to organize the information in clusters of objects, as homogeneously as possible according to their spectral energy distributions, and to project them onto a 2D grid where the data structure can be visualized.

Our algorithm has been tested by means of simulated Gaia spectrophotometry (150,000 objects), which is based on SDSS observations and theoretical spectral libraries covering a wide sample of astronomical objects. We demonstrate the usefulness of the method by analyzing over 10,000 objects, mostly fainted objects and unsuccessful observations, that were rejected by the SDSS spectroscopic classification pipeline and thus classified as “UNKNOWN”. This dataset was transformed to Gaia BP and RP format by the use of GOG simulator.

GUASOM provides a useful toolbox to study the data distribution in extense archives. Even more, the discovered neighbourhood relationships help to unveil the physical nature of objects never observed before. To this effect, we used the SIMBAD catalog to perform crossmatching with the SDSS astrometry, seeking for more identifications.

Type Ia supernovae are thought to be the outcome of the thermonuclear explosion of a carbon–oxygen white dwarf in a close binary system. In this review we discuss the observational background, the possible progenitors, the mechanisms leading to the instability and the development of the explosion itself as well as the remaining uncertainties.

The three instruments on the Herschel Space Observatory, HIFI, SPIRE, and PACS, cover together over a decade in frequency, from 450 GHz to 5000 GHz, with spectral resolutions δν/ν between 0.3 and 10-6. The equivalent temperature range, defined by T = hν/k is 21 K ≤ Teq ≤ 240 K, and thus for dust emission, Herschel will cover the peak of the Planck function in many sources associated with both quiescent and star-forming molecular clouds, both in the Milky Way and other galaxies. The temperature equivalence of the Herschel frequency range also means that essentially all portions of giant molecular clouds will be well probed by the many spectral lines in the Herschel wavelength range of 0.67 mm to 60 µm. My focus in this paper is on gas phase spectral lines of molecules, atoms, and ions, which will be well resolved with the heterodyne receivers on HIFI, but typically not resolved in Galactic sources with the other two instruments. Kinematic interpretation of spectral lines with HIFI is of great interest, along with determination of temperature, density, and column density. I briefly summarize in this review the most important species for Herschel observations, and discuss how one can derive important astronomical quantities from data obtained with the Herschel Space Observatory. Along with describing techniques for analyzing data from the Herschel instruments, I will cover briefly what supplementary ground–based observations are necessary to extract the most from the valuable observing time of the space–based facility.

This paper analyses cosmological observations within inhomogeneous and exact solutions of the Einstein equations. In some way the analyses presented here can be freed from assumptions such as small amplitude of the density contrast.The supernova observations are analysed using the Lemaître–Tolman model and the CMB observations are analysed using the quasispherical Szekeres model.The results show that it is possible to fit the supernova datawithout the cosmological constant. However ifinhomogeneities of sizes and amplitudes as observed in the local Universeare considered, their impact on cosmological observations is small.

We analyze two X-shooter spectra of the GRB 120327A afterglow, acquired    2.1 and    30hrs after the trigger. The ISM in the GRB host galaxy at z = 2.8145 isextremely rich in absorption features, with three components contributing to the lineprofiles. The hydrogen column density associated with GRB 120327A islog NHI / cm2 = 22.01 ± 0.09,and the metallicity of the host galaxy is in the range [X/H] =  − 1.7 to  − 1 with respectto the solar values, i.e., a typical value for a GRB host galaxy. Inaddition to the ground state lines, we detect in the first observation several excitedabsorption features, which disappeared in the second observation. Using these features, wederive that component I is at dI = 200+100-60 pc from the GRB, while component II is located closer,at dII = 100+4030 pc. These values are among the lowest found in GRBs.Comparing the abundances with star formation history models, we find that the GRB 120327Ahost galaxy abundances are compatible with a star formation efficiency of 10Gyr-1, typical of spheroids (elliptical or bulge).

We investigate the nature of the clumpy structures seen at high redshift.For this we use a 3D chemodynamical simulationincluding dark matter, stars and a multiphase interstellar medium aswell as feedback processes from the stars. The infall of baryonicmatter leads to the formation of a disk which later fragments anddevelops starforming sub-galactic clumps. Calculating U, B, V, Kcolors of the model including absorption by interstellar material wefind similar morphology and colors as for multiple clump and chaingalaxies in the HDF.

Based on my direct personal experience as an author, referee, editor, and PhD thesissupervisor, I present in this paper some advice and guidelines on writing scientificpapers. This article copes with the preparation of manuscripts, with the handling ofcopyrights and permissions to reproduce, with communicating with editors and referees, andwith avoiding common errors. More than two dozen FAQs are dealt with, among others: whoshould be coauthor, what is honorary authorship, how to settle the order of author names,may the list of authors change during the review process, who submits the manuscript tothe Editor, must one wait for coauthors’ consent to submit, when to submit a manuscript toastro-ph, how to communicate with the referee, with whom to share a referee report, canstudents be referee, how to cite and quote a straying paper, how to cope with writer’sblock, should others be allowed to completely rewrite a manuscript, how to review a paper,how to revise a multi-author paper, when to ask for another referee, why do Editors edit,and why do referees review?

This paper aims at describing (broad lines) the various instrumental concepts for nulling interferometry and how some observational constraints have driven the evolution from the initial Bracewell configuration to the ESA-Darwin mission configuration. Before this short overview, basic principles of interferometry and of nulling interferometry are recalled. Since a key point in the nulling mode is to insert achromatic phase shifts between interfering waves, a short description of several Achromatic Phase Shifters concepts is given as well as the associated constraints.

The analysis of a sample of 30 isolated spiral galaxies with andwithout an Active Galactic Nucleus (AGN) results in active and control galaxies having similarbulge and disk properties. Secondary bars also seem to beindistinguishable. Circumnuclear kinematics are also analyzed todisentangle what kind of mechanisms are taking place in thecircumnuclear regions. From long slit spectra of a subsample ofisolated active and non-active spiral galaxies in the Hαemission line region, the shape and properties of the rotation curvesare obtained together with the line ratios used to estimate themetallicity of all the detected HII regions. Kinematics andmetallicities are also studied in comparison with the propertiesdetermined for a family of 111 spiral galaxies with a welldetermined environmental status, ranging from isolation to close, though not disruptive, interaction with satellites or companions. Thestellar kinematics are also studied in some cases, with as mainresult the detection of a stellar velocity dispersion drop in thecenters of four Seyfert galaxies. Together with previous findings, ourresults from the comparison between active and non-active isolatedgalaxies point to AGNs being an episode in the life of galaxies,provided that the fuel is available and the accumulation mechanismsare at work.

We present two newly discovered cE galaxies with tidal tails, the “smoking gun” of the stripping scenario for cE formation.

In this talk I have presented the data analysis results of extracting properties of halo WIMPs: the mass and the (ratios between the) spin–independent and spin–dependent couplings/cross sections on nucleons by the amidas website. Although non–standard astronomical setup has been used to generate pseudodata sets for our analyses, it has been found that, without prior information/assumption about the local density and velocity distribution of halo Dark Matter, these WIMP properties have been reconstructed with  ~5% to ≲40% deviations from the input values.

The internal antarctic plateau revealed in the last years to be a site with interesting potentialities for the astronomical applications due to the extreme dryness and low temperatures, the typical high altitude of the plateau, the weak level of turbulence in the free atmosphere down to a just few tens of meters from the ground and the thin optical turbulence layer developed at the ground. The main goal of a site testing assessment above the internal antarctic plateau is to characterize the site (optical turbulence and classical meteorological parameters) and to quantify which is the gain we might obtain with respect to equivalent astronomical observations done above mid-latitude sites to support plans for future astronomical facilities. Our group has been involved, since a few years, in studies related to the assessment of this site for astronomical applications that include the characterization of the meteorological parameters and optical turbulence provided by general circulation models as well as mesoscale atmospherical models and the quantification of the performances of Adaptive Optics (AO) systems. In this talk I will draw the status of art of this site assessment putting our studies in the context of the wide international site testing activity that has been done in Antarctica. I will focus on the site assessment relevant to astronomical applications to be done in the visible up to the near infrared ranges, i.e. those ranges for which the optical turbulence represents a perturbing element for the quality of the images and the AO techniques an efficient tool to correct these wavefront perturbations.

Two competing theories posit that Ultra Compact Dwarfs (UCDs) form either as the stripped nuclei of dwarf galaxies or as giant globular clusters (GGCs) associated with the largest globular cluster (GC) systems. By focussing on the field and group environments where young UCDs may be most common, we have discovered the first UCD that is clearly the result of recent (< 4Gyr ago) stripping of a companion galaxy during a minor galaxy merger. However, we have also found a definitive case of a multiple-UCD system created via GC formation processes, which are likely associated with major galaxy mergers.

Spectral data reduction is a crucial step, as so important as the acquisition process. Rigor shall be as well applied at this stage to not degrade the quality of the data acquired. It is the last step before the computation of the astrophysical quantities. It is thus necessary to understand what is involved in each processing steps and the underlying limitations. Thus limitations or limit conditions are usually embedded and then hidden in a specific software command that everyone use without completely mastering what is really at stake. In this chapter we will introduced the different type of processing and spectral analysis which can dispose an amateur in several software packages. The first processing will treat about basic images correction which are linked to the CCD acquisition and the processes pipeline. We will then describe the different strategy to calibrate the spectral profile in wavelength and the few corrections driven by the earth environment to increase the accuracy of the future measurements. We will end with the description of few tools on quantitative spectral analysis and their limitations. The practice of spectral acquisition and processing is just at its beginning in amateur world. We hope that this section will demystify the essential step of spectral processing and will motivate the amateur to go beyond the contemplative watching of sky wonders.

Recent observations of broad-band afterglow of gamma-ray bursts (GRBs) suggest that thestandard external shock model cannot account for all the data. The observed “afterglow” ofsome GRBs includes the contributions from at least three emission components.Theoretically, there are naturally three emission sites. Besides the traditional externalforward shock, the existence of X-ray flares demands late central engine activities of theGRB central engine, so that an “internal dissipation” region of the late wind is anotheremission site. After dissipation, this late wind would inevitably catch up with theblastwave, giving rise to a third emission site at a long-lasting reverse shock. Somerecent efforts in understanding the broadband afterglow are reviewed.

The BATSE experiment on the Compton Gamma-ray Observatory was the first large detectorsystem designed for the study of gamma-ray bursts. The eight large-area detectors allowedfull-sky coverage and were optimized to operate in the primary energy region of emissionof most GRBs. BATSE provided detailed observations of the temporal and spectralcharacteristics of several thousand GRBs, and it was the first experiment to provide rapidnotifications of the coarse location of many them. It also provided strong evidence forthe cosmological distances to GRBs through the observation of the sky distribution andintensity distribution of numerous GRBs. The large number of GRBs observed with the high-sensitivity BATSE detectors continues to provide a database of GRB spectral and temporalproperties in the primary energy range of GRB emission that will likely not be exceededfor at least another decade. The origin and development of the BATSE experiment, somehighlights from the mission and its continuing legacy are described in this paper.

It has been claimed in the past that in low-metallicity Blue Compact Dwarf (BCDs) galaxies, the N/O value is independent of metallicity (O/H ratio), implying the need to invoke a primary production of nitrogen in intermediate-mass stars, in addition to the secondary nitrogen produced from the CNO cycle in high-mass stars. In order to better understand this controversial issue we undertook an integral field spectroscopic study of the nebular gas within a sample of BCDs previously thought to have anomalously high N/O values. Here we present the results of this study for 3 BCDs: two with anomalous N/O values (Mrk 996 and UM 420) and one with more normal N/O values (UM 462). We describe in detail how we derived the physical conditions (Te, Ne) as a function of position within the galaxy, and as a consequence, how this revealed both revised metallicities and normal N/O ratios and uncovered one of the first clear evidences of nitrogen self-enrichment of an H ii  region from WR stars.

By giving three different definitions of peak flux(original peak flux, corrected peak flux, and scaled peak flux), we analyze the frequency distributions of 14057 flares recorded by GOES from 2000 to 2005. We find a significant result that the frequency distribution of the scaled peak flux for all the sample flares can be approximated by a perfect power-law function with an index of 2.18, without any usually deviating from the power-law at the lower fluxes.

We present new parsec-scale resolution data from a multi-phase study of the ISM in the walls of Galactic supershells. Hi synthesis images and CO survey data reveal a wealth of substructure, including dense-tipped fingers and extended molecular clouds embedded in shell walls. We briefly consider formation scenarios for these features, and suggest that both the interaction of an expanding shell with pre-existing dense clouds, as well as in-situ formation of CNM and molecular gas, are likely to be relevant. Future work will also examine the role of instabilities in structure formation and breakup, and will investigate the presence of high-altitude gas associated with supershells and chimneys.