An infrared view of protostellar shocks

In questa tesi viene presentato lo studio di un campione di oggetti HERBIG-HARO, associati a sorgenti protostellari , tramite l’analisi di spettri nel vicino infrarosso (1-2,5 µ) acquisiti con due strumenti differenziati: Isaac e Sinfoni, montati sul VLT. Lo scopo è la caratterizzazione delle proprietà fisiche, chimiche e cinematiche attraverso l’analisi di righe di emissione molecolari (H₂) ed atomiche (principalmente [FeII]), osservate in queste regioni di shock. Utilizzando opportuni rapporti di righe si è stimata la temperatura, la densità e l’estinzione, mentre lo studio dei profili delle righe più brillanti ha fornito informazioni sulla geometria e sulla struttura di velocità. Questi risultati sono stati usati come vincoli osservativi per la formulazione di nuovi modelli di shock

Far-infrared line spectra of Seyfert galaxies from the Herschel-PACS Spectrometer

We present spectroscopic observations of FIR fine-structure lines of 26 Seyfert galaxies obtained with the Herschel-PACS spectrometer. These observations are complemented by spectroscopy with Spitzer-IRS and Herschel-SPIRE. The ratios of the OIII, NII, SIII and NeV lines have been used to determine electron densities in the ionised gas regions. The CI lines, observed with SPIRE, have been used to measure the densities in the neutral gas, while the OI lines provide a measure of the gas temperature, at densities below 10000 cm-3. Using the OI145/63um and SIII33/18um line ratios we find an anti-correlation of the temperature with the gas density. Using various fine-structure line ratios, we find that density stratification is common in these active galaxies. On average, the electron densities increase with the ionisation potential of the ions producing the NII, SIII and NeV emission. The infrared emission lines arise partly in the Narrow Line Region (NLR) photoionised by the AGN central engine, partly in HII regions photo ionised by hot stars and partly in neutral gas in photo-dissociated regions (PDRs). We attempt to separate the contributions to the line emission produced in these different regions by comparing our emission line ratios to empirical and theoretical values. In particular, we tried to separate the contribution of AGN and star formation by using a combination of Spitzer and Herschel lines, and we found that, besides the well known mid-IR line ratios, the mixed mid-IR/far-IR line ratio of OIII88um/OIV26um can reliably discriminate the two emission regimes, while the far-IR line ratio of CII157um/OI63um is only able to mildly separate the two regimes. By comparing the observed CII157um/NII205um ratio with photoionisation models, we also found that most of the CII emission in the galaxies we examined is due to PDRs.Comment: Accepted for publication in ApJ Main Journal on the 5th November 2014, 25 pages, 16 figure

Progetto Herschel - WP: IF web per CuTEx nei tool ASDC

Le specifiche contenute in questo documento si riferiscono alla attività descritta nel Piano delle Attività 2012 della Missione Herschel nel punto 5.1: “Integrazione nei tool on-line del software CuTEx per la detection e l’analisi fotometrica di sorgenti all’interno di campi affollati ed a background variabile” Il software CuTEx, sviluppato originariamente nel linguaggio IDL (Molinari et al. 2011), è un algoritmo in grado di effettuare la detezione (Detection) di sorgenti su immagini fotometriche e di ottenere il flusso (Photometry) di queste. I tool di Detection e di Photometry sono stati esportati nel linguaggio GDL. Sono stati, inoltre, testati e validati utilizzando diverse tipologie di campi fotometrici

Jython scripts for the achievement of the Herschel Archive at the MMIA

The jython scripts used to generate the the archive of Herschel data within the MMIA are developed and holden by the Herschel Team within the HIPE software environment. This document is intended to archive the scripts and to provide a quick description of their functionality

The Herschel Science Archive at the ASDC Multi-Mission Interactive Archive

The science archive of the Herschel Space Observatory at the ASCD is conceived for including public high level products of the Herschel mission within the structure of the ASDC Multi-Mission Interactive Archive (MMIA). High level products are scientific products (Level 2) and they are available to the users in formats (FITS, ASCII tables) that can be directly used for scientific analysis without further processing steps. The users access to the scientific products through an user-friendly web interfaces, which does not assumes a particular knowledge about the satellite, the on-board instruments and the related observing modes. Scientific products are firstly Standard Level 2 products, which are released by the HSC. The Standard products are obtained by performing queries at HSA using jython scripts developed within the HIPE environments. The Level 2 Standard Products are extracted from the Observational Context and are archived in the section of the Multi-Mission Interactive Archived dedicated at the Herschel data. Together with the standard products extracted from the HSA, an observation can present reprocessed products obtained by using both the standard pipelines, which are released by the HSC, and non-standard pipelines, which are developed outside the ICC and that are currently available at the ASDC. The reprocessing is aimed for optimizing the final products in the case of specific observing modes. The standard recipes are used for combining observations acquired in large map photometric modes with the PACS and SPIRE instruments, and for performing further processing steps on HIFI spectra, in order to improve the quality of the final results. Non-standard pipeline are developed by the astronomical community with the purpose of obtaining scientific products with increased quality with respect to the standard pipeline. The efforts have been mainly focused in reducing large photometric maps obtained using PACS and SPIRE instruments. Two non-standard pipelines are currently available at the ASDC that can be used to populate the archive: "Scanamorphos" (Roussel, H. 2011, submitted to A & A), and "Romagal" (Traficante, A. 2011, MNRAS submitted). Scanamorphos is a pipeline already released to the community, while Romagal is still a private code, since it is in a optimization phase, and the ASDC actively contributes to the development and maintenance of the code. The Herschel Team at the ASDC is in charge of developing the scripts able to produce the archive and the auxiliary files, together with the statements necessary for developing the web interfaces to the Herschel archive and for correctly performing the queries to the database. The development environment, where the the data archive is created and tested, is set in the virtual machine vmherschel64bit; whenever the archive is ready to be released, it is exported to the server mysql by using the technical support provide by Telspazio. This document is intended to provide a complete description of the Herschel Science Archive at the ASDC and the implementation of scientific data within the MMIA. Therefore, the Herschel instruments and, in particular, the observing modes associated are not described in details and they are reported without further explanations. It is remanded to the Observer Manuals (see bibliograpy) for having detailed information about observing capabilities of the scientific instruments

Advanced GLS map-making for the Herschel's photometers

We discuss Generalised Least Squares (GLS) map-making for the data of the Herschel satellite's photometers, which is a difficult task, due to the many disturbances affecting the data, and requires appropriate pre- and post-processing. Taking an existing map-maker as a reference, we propose several advanced techniques, which can improve both the quality of the estimate and the efficiency of the software. As a main contribution we discuss two disturbances, which have not been studied yet and may be detrimental to the image quality. The first is a data shift, due to delays in the timing system or in the processing chain. The second is a random noise, termed pixel noise, due to the jitter and the approximation of the pointing information. For both these disturbances, we develop a mathematical model and propose a compensation method. As an additional contribution, we note that the performance can be improved by properly adapting the algorithm parameters to the data being processed and discuss an automatic setting method. We also provide a rich set of examples and experiments, illustrating the impact of the proposed techniques on the image quality and the execution spee

Least squares time-series synchronization in image acquisition systems

We consider an acquisition system constituted by an array of sensors scanning an image. Each sensor produces a sequence of readouts, called a time series. In this framework, we discuss the image estimation problem when the time series are affected by noise and by a time shift. In particular, we introduce an appropriate data model and consider the least squares (LS) estimate, showing that it has no closed form. However, the LS problem has a structure that can be exploited to simplify the solution. In particular, based on two known techniques, namely, separable nonlinear LS and alternating LS, we propose and analyze several practical estimation methods. As an additional contribution, we discuss the application of these methods to the data of the photodetector array camera and spectrometer, which is an infrared photometer onboard the Herschel satellite. In this context, we investigate the accuracy and the computational complexity of the methods, using both true and simulated dat

UNIMAP. A generalized least-squares map maker for Herschel data

The Herschel space telescope hosts two infrared photometers having an unprecedented resolution, sensitivity and dynamic range. The map making, i.e. the formation of sky images from the instruments' data, is critical for the full exploitation of the satellite and is a difficult task, since the readouts are affected by several disturbances, most notably by correlated noise. An effective map making approach is based on generalized least squares (GLS). However, when applied to Herschel data this approach poses several challenges and requires a specific pre- and post-processing. In the paper, we describe these challenges and introduce a set of algorithms and procedures which successfully address the issues. We also describe the implementation of the procedures and how these are integrated into an image formation software called UNIMAP, which is the first GLS map maker capable of automatically producing quality Herschel images with manageable memory and complexity requirements.The Herschel space telescope hosts two infrared photometers having an unprecedented reso- lution, sensitivity and dynamic range. The map making, i.e. the formation of sky images from the instruments’ data, is critical for the full exploitation of the satellite and is a difficult task, since the readouts are affected by several disturbances, most notably by correlated noise. An effective map making approach is based on generalized least squares (GLS). However, when applied to Herschel data this approach poses several challenges and requires a specific pre- and post-processing. In the paper, we describe these challenges and introduce a set of algorithms and procedures which successfully address the issues. We also describe the implementation of the procedures and how these are integrated into an image formation software called UNIMAP , which is the first GLS map maker capable of automatically producing quality Herschel images with manageable memory and complexity requirements