Evolution of compact groups from intermediate to final stages: A case study of the HI content of HCG 16

Hickson Compact Group (HCG) 16 is a prototypical compact group of galaxies, apparently in an intermediate stage of evolution, where its galaxies are losing gas to the intra-group medium (IGrM). The wide variety of ongoing process in HCG 16 make it an ideal case study for exploring which processes are likely to dominate the late stages of evolution in compact groups. In order to build a coherent picture of the evolution of this group we make use of the multi-wavelength data available, but focus particularly on HI as a tracer of interactions and evolutionary phase. We reprocess archival VLA L-band data of HCG 16 using the multi-scale CLEAN algorithm to accurately recover diffuse features. Despite the clear disruption of the HI component of HCG 16 we find that it is not globally HI deficient, even though HCG 16a and b have lost the majority of their HI and almost 50% of the group's HI is in the IGrM, including a 160 kpc long tail extending towards the SE. This study indicates that in the recent past (~1 Gyr) galaxies HCG 16a and b likely underwent major interactions that unbound gas without triggering significant star formation. This gas was then swept away by a high speed, close encounter with NGC 848. The starburst events HCG 16c and d have triggered galactic winds which, in the case of HCG 16d, appears to have disrupted its HI reservoir. The tidal features still connected to these galaxies indicate that more HI will soon be lost to the IGrM, while that which remains in the discs will likely be consumed by star formation episodes. This is expected to result in a collection of gas-poor galaxies embedded in a diffuse HI structure, which will gradually be evaporated by the UV background, resembling the final stage of the evolutionary model of compact groups. This work is accompanied by a complete workflow to reproduce the final data products, intended to improve reproducibility. (Abridged)Comment: Accepted for publication in A&A, 35 pages, 18 figure

Study o the origin of Hi asymmetries of highly isolated galaxy CIG 96 by means of deep optical and Hi observations

Throughout the years, many studies have addressed the numerous questions raised when trying to understand how the galaxies assemble and evolve. This topic constitutes one of the most studied fields of modern astronomy and, as we expand our knowledge of the different elements of a galaxy and their evolutionary roles, new problems arise. Some of them may be solved with deeper and higher resolution observations that let us detect the fine print of the processes shown in the different evolutionary stages. The Analysis of the interstellar Medium of Isolated GAlaxies project (AMIGA) seeks to provide a better understanding on the formation and evolution of galaxies focusing on those that lie in relatively uninhabited environments in comparison with denser ones, including the field galaxies. AMIGA has been performing a systematic multi−wavelength study of a selected and statistically significant sample of extremely isolated galaxies based on a refined version of the Catalog of Isolated Galaxies (CIG). In absence of companions, the CIG galaxies constitute an ideal laboratory to study secular evolution and. Since the foundation, the AMIGA project has been investigating the internal and environmental processes of these galaxies, as well as the implication in the theories of galaxy formation and evolution. This project constitutes the framework for the present dissertation. Asymmetries in the atomic hydrogen (HI) of galaxies are often caused by the interaction with close companions. The AMIGA project has demonstrated that isolated galaxies show the lowest levels of asymmetry in their HI integrated profiles compared to other samples, even field galaxies. However, some galaxies present high asymmetry ratios whose origins are poorly understood. Aiming to investigate the source of the asymmetries, we selected a sample that consists of 184 isolated galaxies from the CIG catalog. Out of them, the highly isolated galaxy CIG 96 (NGC864) shows a 16% asymmetry level in its HI integrated profile, representing a model case and main target of this study. In order to try to reveal the causes of the asymmetry, we performed deep optical observations of CIG 96 with the CAHA1.23m, CAHA2.2m and VST (with the OmegaCAM wide field camera) telescopes. We reach surface brightness limits of μCAHA2.2m =27.5 mag arcsec−2 (Cousins R) and μV ST =28.7 mag arcsec−2 (SDSS r) that show the pseudoring of the galaxy and its star forming regions in detail. Additionally, a wavelet filtering of the HI data cube from our deep observations with VLA/EVLA telescope allowed us to reach a column density of NHI =8.9×1018 cm−2 (5σ, 28”×28” beam), the lowest of any isolated galaxy to date. We confirm that the HI extends farther than 4×r25 in all directions and also detect two previously undetected gaseous structures (∼106M⊙) in the outskirts of the galaxy. The SDSS g−r colour index image from CAHA1.23m shows extremely blue colours in certain regions of the pseudoring (suggesting regions with star formation) where NHI >8.5×1020 cm−2, whereas the rest show red colours. Galactic cirrus contaminate some regions of the field, setting an unavoidable detection limit at 28.5 mag arcsec−2 (SDSS r). At the current surface brightness (SB) and HI column density (NHI) limit levels, we detect no stellar link within 1◦×1◦ neither gaseous link within 40’×40’ between CIG 96 and any companion. The isolation criteria rule out interactions with other similar sized galaxies for at least ∼2.7 Gyr. Using existing stellar evolution models, the age of the pseudoring is estimated to be 1 Gyr or older. Undetected companions previously accreted and cold gas accretion remain as the main hypothesis to explain its optical pseudoring and HI features. The deep optical and HI observations have let us unveil previously undetected features of CIG 96, showing they are a key tool for the study of the HI distribution asymmetry and their causes in isolated galaxies. Hence, all the deep optical data of CIG 96 and other targets presented in this dissertation guarantee the continuation of the project, they may potentially open new research paths within the AMIGA project and, in the end, help us to expand our knowledge on galaxy formation and evolution.Tesis Univ. Granada. Programa Oficial de Doctorado en Física y Matemática

Brillo de fondo de cielo con AstMon-UCM

AstMon-UCM (All Sky Transmission MONitor) es una cámara de todo el cielo dedicada a medir la calidad astronómica del cielo nocturno. Este instrumento está instalado en el Observatorio UCM (Facultad de CC. Físicas) y de manera autónoma toma imágenes en bandas B, V y R de Johnson para determinar las constantes de extinción atmosférica y realizar mapas de brillo de fondo de cielo nocturno. Es el primer instrumento de su clase instalado en un observatorio astronómico urbano y por lo tanto sirve para estudiar los efectos de la contaminación lumínica en el brillo del cielo. Se muestran detalles de su instalación, operación y resultados hasta la fecha de publicación de esta memoria. ---------------------------------- AstMon-UCM (All Sky Transmission MONitor) is an all-sky camera devoted to measure the astronomical quelity of the night sky. This device belongs to the astronomical observatory of the UCM (Observatorio UCM) on top of the Physics building. Images in B, V and R bands of the Johnson system taken by AstMon-UCM are used to determine atmospheric extinction and to map the night sky brightness. It is the first device of its type installed in an urban observatory and it is useful to study the effects of Light Pollution on the night sky brightness. A description of AstMon-UCM and its operation is included in this report. Results up to the publication date are also included

Study of the origin of HI asymmetries of the highly isolated galaxy CIG 96 by means of deep optical and HI observations

Throughout the years, many studies have addressed the numerous questions raised when trying to understand how the galaxies assemble and evolve. This topic constitutes one of the most studied fields of modern astronomy and, as we expand our knowledge of the different elements of a galaxy and their evolutionary roles, new problems arise. Some of them may be solved with deeper and higher resolution observations that let us detect the fine print of the processes shown in the different evolutionary stages. The Analysis of the interstellar Medium of Isolated GAlaxies project (AMIGA) seeks to provide a better understanding on the formation and evolution of galaxies focusing on those that lie in relatively uninhabited environments in comparison with denser ones, including the field galaxies. AMIGA has been performing a systematic multi−wavelength study of a selected and statistically significant sample of extremely isolated galaxies based on a refined version of the Catalog of Isolated Galaxies (CIG). In absence of companions, the CIG galaxies constitute an ideal laboratory to study secular evolution and. Since the foundation, the AMIGA project has been investigating the internal and environmental processes of these galaxies, as well as the implication in the theories of galaxy formation and evolution. This project constitutes the framework for the present dissertation. Asymmetries in the atomic hydrogen (HI) of galaxies are often caused by the interaction with close companions.The AMIGA project has demonstrated that isolated galaxies show the lowest levels of asymmetry in their HI integrated profiles compared to other samples, even field galaxies. However, some galaxies present high asymmetry ratios whose origins are poorly understood. Aiming to investigate the source of the asymmetries, we selected a sample that consists of 184 isolated galaxies from the CIG catalog. Out of them, the highly isolated galaxy CIG 96 (NGC 864) shows a 16% asymmetry level in its HI integrated profile, representing a model case and main target of this study. In order to try to reveal the causes of the asymmetry, we performed deep optical observations of CIG 96 with the CAHA1.23m, CAHA2.2m and VST (with the OmegaCAM wide field camera) telescopes. We reach surface brightness limits of µCAHA2.2m = 27.5 mag arcsec−2 (Cousins R) and µV ST = 28.7 mag arcsec−2 (SDSS r) that show the pseudoring of the galaxy and its star forming regions in detail. Additionally, a wavelet filtering of the HI data cube from our deep observations with VLA/EVLA telescope allowed us to reach a column density of NHI = 8.9 ×1018 cm−2 (5σ, 28” × 28” beam), the lowest of any isolated galaxy to date. We confirm that the HI extends farther than 4×r25 in all directions and also detect two previously undetected gaseous structures (∼106 M⊙) in the outskirts of the galaxy.The SDSS g−r colour index image from CAHA1.23m shows extremely blue colours in certain regions of the pseudoring (suggesting regions with star formation) where NHI > 8.5 × 1020 cm−2 , whereas the rest show red colours. Galactic cirrus contaminate some regions of the field, setting an unavoidable detection limit at 28.5 mag arcsec−2 (SDSS r). At the current surface brightness (SB) and HI column density (NHI ) limit levels, we detect no stellar link within 1◦×1 ◦ neither gaseous link within 40’×40’ between CIG 96 and any companion. The isolation criteria rule out interactions with other similar sized galaxies for at least ∼2.7 Gyr. Using existing stellar evolution models, the age of the pseudoring is estimated to be 1 Gyr or older. Undetected companions previously accreted and cold gas accretion remain as the main hypothesis to explain its optical pseudoring and HI features. The deep optical and HI observations have let us unveil previously undetected features of CIG 96, showing they are a key tool for the study of the HI distribution asymmetry and their causes in isolated galaxies. Hence, all the deep optical data of CIG 96 and other targets presented in this dissertation guarantee the continuation of the project, they may potentially open new research paths within the AMIGA project and, in the end, help us to expand our knowledge on galaxy formation and evolutionPeer reviewe

ISS nocturnal images as a scientific tool against Light Pollution

The potential of the night pictures taken from the International Space Station (ISS) with a Nikon D3s digital camera to fight against light pollution is shown. A scientific analysis of ISS026-E-26493 RAW image of Madrid at night with techniques used by astronomers and cartographers is performed. We suggest an observational setup to obtain useful scientific information from the pictures including series of exposures and calibration frames

A comprehensive examination of the optical morphologies of 719 isolated galaxies in the AMIGA sample

Using images from Sloan Digital Sky Survey Data Release 8, we have re-examined the morphology of 719 galaxies from the Analysis of the interstellar Medium in Isolated GAlaxies (AMIGA) project, a sample consisting of the most isolated galaxies that have yet been identified. The goal is to further improve the classifications of these galaxies by examining them in the context of the Comprehensive de Vaucouleurs revised Hubble-Sandage (CVRHS) system, which includes recognition of features that go beyond the original de Vaucouleurs point of view. Our results confirm previous findings that isolated galaxies are found across the complete revised Hubble sequence, with intermediate- to late-type (Sb-Sc) spirals being relatively more common. Elmegreen Arm Classifications are also presented, and show that more than 50 per cent of the 514 spirals in the sample for which an arm class (AC) could be judged are grand design (AC 8,9,12). The visual bar fraction for the sample is ≈50 per cent, but only 16 per cent are classified as strongly barred (SB). The dominant family classification is SA (non-barred), the dominant inner variety classification is (s) (pure spiral), and the dominant outer variety classification is no outer ring, pseudo-ring, or lens. The Kolmogorov–Smirnov test is used to check for potential biases in the morphological interpretations, and for any possible relation between rings, bars, and ACs with local environment and far-infrared excess. The connection between morphology and stellar mass is also examined for a subset of the sample. © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.We acknowledge the support of grant AYA2015-65973-C3-1-R from the European Regional Development Fund (FEDER), through the Spanish Ministry of Economy and Competitveness (MINECO). This work has also been supported by the Spanish Science Ministry 'Centro de Excelencia Severo Ochoa' Program under grant SEV-2017-0709. MJ is supported by a Juan de la Cierva formacion fellowship. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England.Peer reviewe

Towards a FAIR understanding of compact group evolution: A case study of HCG16

Contributions to the XIV.0 Scientific Meeting (virtual) of the Spanish Astronomical Society, held 13-15 July 2020, online at https://www.sea-astronomia.es/reunion-cientifica-2020, id.52With funding from the Spanish government through the Severo Ochoa Centre of Excellence’accreditation SEV-2017-070

Towards a FAIR understanding of compact group evolution: A case study of HCG16

The 2019 SKA Science Meeting, entitled “New Science enabled by New Technologies in the SKA Era”, held at Alderley Park in Alderley Edge (UK) on April 8th to 12th, 2019

Evolution of compact groups from intermediate to final stages. A case study of the H

Hickson Compact Group (HCG) 16 is a prototypical compact group of galaxies in an intermediate stage of the previously proposed evolutionary sequence, where its galaxies are losing gas to the intra-group medium (IGrM). The group hosts galaxies that are H I-normal, H I-poor, and centrally active with both AGNs and starbursts, in addition to a likely new member and a H I tidal feature of similar to 160 kpc in length. Despite being a well-studied group at all wavelengths, no previous study of HCG16 has focused on its extraordinary H I component. Aims. The characteristics of HCG16 make it an ideal case study for exploring which processes are likely to dominate the late stages of evolution in compact groups, and ultimately determine their end states. In order to build a coherent picture of the evolution of this group we make use of the multi-wavelength data available, but focus particularly on H I as a tracer of interactions and evolutionary phase. Methods. We reprocess archival VLA L-band observations of HCG16 using the multi-scale CLEAN algorithm to accurately recover diffuse features. Tidal features and galaxies are separated in three dimensions using the SlicerAstro package. The H I deficiency of the separated galaxies is assessed against the benchmark of recent scaling relations of isolated galaxies. This work has been performed with particular attention to reproducibility and is accompanied by a complete workflow to reproduce all the final data products, figures, and results. Results. Despite the clear disruption of the H I component of HCG16 we find that it is not globally H I deficient, even though HCG16a and b have lost the majority of their H I and almost 50% of the group's H I is in the IGrM. The H I content of HCG16d shows highly disturbed kinematics, with only a marginal velocity gradient that is almost perpendicular to its optical major axis. The tail of similar to 160 kpc in length extending towards the southeast appears to be part of an even larger structure which spatially and kinematically connects NGC848 to the northwest corner of the group. Conclusions. This study indicates that in the recent past (similar to 1 Gyr) galaxies HCG16a and b likely underwent major interactions that unbound gas without triggering significant star formation. This gas was then swept away by a close, high-speed encounter with NGC848. The starburst events HCG16c and d, likely initiated by their mutual interaction, triggered galactic winds which, in the case of HCG16d, appear to have disrupted its H I reservoir. The tidal features still connected to all these galaxies indicate that more H I will soon be lost to the IGrM, while that which remains in the discs will likely be consumed by star-formation episodes triggered by their ongoing interaction. This is expected to result in a collection of gas-poor galaxies embedded in a diffuse H I structure, which will gradually (over several Gyr) be evaporated by the UV background, resembling the final stage of the evolutionary model of compact groups.MGJ is supported by a Juan de la Cierva formacion fellowship. We also acknowledge support from the grants AYA2015-65973-C3-1-R and RTI2018-096228-B-C31 (MINECO/FEDER, UE). This work has been supported by the Spanish Science Ministry >Centro de Excelencia Severo Ochoa> program under grant SEV-2017-0709. MGJ wishes to thank B. Koribalski, K. Lee-Waddell, and S. Cazzoli for helpful discussions. We also thank the referee for his thorough comments which helped to improve this paper. This project used archival data from the VLA. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This project used data obtained with the Dark Energy Camera (DECam), which was constructed by the Dark Energy Survey (DES) collaboration (full acknowledgement at legacysurvey.org/acknowledgment). This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. We also acknowledge the use of the HyperLeda database (Makarov et al. 2014). This research made use of APLpy, an open-source plotting package for Python (Robitaille & Bressert 2012; Robitaille 2019), astropy (Astropy Collaboration 2013, 2018), Aladin (Bonnarel et al. 2000), mayavi (Ramachandran & Varoquaux 2011), and SAOImageDS9 (Joye & Mandel 2003)