Emilio José García

The AMIGA project - I. Optical characterization of the CIG catalog

The AMIGA project (Analysis of the Interstellar Medium of Isolated Galaxies) is compiling a multiwavelength database of isolated galaxies that includes optical (B and Hα), infrared (FIR and NIR) and radio (continuum plus HI and CO lines) properties. It involves a refinement of the pioneering Catalog of Isolated Galaxies. This paper is the first in a series and begins with analysis of the global properties of the nearly redshift-complete CIG with emphasis on the Optical Luminosity Function (OLF) which we compare with other recent estimates of the OLF for a variety of environments. The CIG redshift distribution for n = 956 galaxies re-enforces the evidence for a bimodal structure seen earlier in smaller samples. The peaks at redshift near 1500 and 6000 km s −1 , corresponding respectively to galaxies in the local supercluster and those in more distant large-scale components (particularly Perseus-Pisces). The two peaks in the redshift distribution are superimposed on 50% or more of the sample that is distributed in a much more homogeneous way. The CIG probably represents the most homogeneous local field example that has ever been compiled. Our derivation of the CIG OLF is consistent with other studies of the OLF for lower density environments. This comparison via the Schechter parameter formalization shows that: 1) M ∗ increases with galaxy surface density on the sky and 2) α shows a weaker tendency to do the same. The CIG represents the largest and most complete foundation for studies of isolated galaxies and is likely as close as we can come to a field sample.

The AMIGA sample of isolated galaxies. V. Quantification of the isolation

Context. The AMIGA project aims to build a well defined and statistically significant reference sample of isolated galaxies in order to estimate the environmental effects on the formation and evolution of galaxies. Aims. The goal of this paper is to provide a measure of the environment of the isolated galaxies in the AMIGA sample, quantifying the influence of the candidate neighbours identified in our previous work and their potential effects on the evolution of the primary galaxies. Here we provide a quantification of the isolation degree of the galaxies in this sample. Methods. Our starting sample is the Catalogue of Isolated Galaxies (CIG). We used two parameters to estimate the influence exerted by the neighbour galaxies on the CIG galaxy: the local number density of neighbour galaxies and the tidal strength affecting the CIG galaxy. We show that both parameters together provide a comprehensive picture of the environment. For comparison, those parameters have also been derived for galaxies in denser environments such as triplets, groups and clusters. Results. The CIG galaxies show a continuous spectrum of isolation, as quantified by the two parameters, from very isolated to interacting. The fraction of CIG galaxies whose properties are expected to be influenced by the environment is however low (159 out of 950 galaxies). The isolated parameters derived for the comparison samples gave higher values than for the CIG and we found clear differences for the average values of the 4 samples considered, proving the sensitivity of these parameters. Conclusions. The environment of the galaxies in the CIG has been characterised, using two complementary parameters quantifying the isolation degree, the local number density of the neighbour galaxies and the tidal forces affecting the isolated galaxies. A final catalogue of galaxies has been produced and the most isolated of these galaxies are consequently appropriate to serve as a reference sample for the AMIGA project.

The AMIGA sample of isolated galaxies III. IRAS data and infrared diagnostics

Aims. We describe the mid- (MIR) and far- (FIR) infrared properties of a large (∼1000) sample of the most isolated galaxies in the local Universe. This sample is intended as a “nurture-free” zero point against which more environmentally influenced samples can be compared. Methods. We reprocess IRAS MIR/FIR survey data using the ADDSCAN/SCANPI utility for 1030 out of 1050 galaxies from the Catalogue of Isolated Galaxies (CIG) as part of the AMIGA project. We focus on diagnostics (FIR luminosity LFIR, R = log(LFIR/LB), and IRAS colours) thought to be sensitive to effects of environment or interaction. Results. The distribution of log(LFIR) sharply peaks from 9.0–10.5, with very few (<2%) galaxies above 10.5. Review of available optical images of the most FIR luminous galaxies finds the majority likely to be interacting systems missed in our earlier morphological reevaluation. The optically normalised luminosity diagnostic R = log(LFIR/LB) shows a sharply peaked distribution between 0.0 and −1.0. These results were compared to the magnitude limited sample of the Center for Astrophysics that was selected without environmental discrimination. This modestly (e.g., compared to cluster, binary galaxy, and compact group samples) environmentally affected sample shows a significantly higher mean log(LFIR), and R, whereas the mean log(LB) is the same. Our sample shows a strong LFIR vs. LB correlation, with a slope steeper than one (LFIR ∝ L 1.41 B ). Interacting galaxies were found above this correlation, showing an enhancement in LFIR. With respect to the IRAS colours, we found higher F60/F100 values for ellipticals and late-type galaxies than for spirals, indicating a higher dust temperature. The mean value of F60/F100 was found to be lower than for interacting samples from the literature. Conclusions. The results indicate that the FIR emission is a variable enhanced by interaction, and that our sample probably shows the lowest possible mean value. This attests to the utility of our sample for defining a nurture-free zero point.

The AMIGA sample of isolated galaxies - II. Morphological refinement

Received / accepted Abstract. We present a complete refinement of the optical morphologies for galaxies in the Catalog of Isolated Galaxies (Karachentseva 1973) that forms the basis of the AMIGA (Analysis of the interstellar Medium of Isolated GAlaxies) project. Uniform reclassification using the digitized POSS II benefit ed from the high resolution and dynamic range of that sky survey. Comparison with independent classifications made for an SDS S overlap sample of more than 200 galaxies confirms the reli- ability of the early vs. late-type discrimination and the ac curacy of spiral subtypes withinT = 1-2. CCD images taken at the Observatorio de Sierra Nevada were also used to solve ambiguities in early versus late-type classifications. A consi derable number of galaxies in the catalog (n = 193) are flagged for the presence of nearby companions or sign s of distortion likely due to interaction. This most isolated sample of galaxies in the local Universe is dominated by two populations: 1) 82% spirals (Sa-Sd) with the bulk being luminous systems with small bulges (63% between types Sb-Sc) and 2) a significant population o f early-type E-S0 galaxies (14%). Most of the types later than Sd are low luminosity galaxies concentrated in the local superclus- ter where isolation is diffi cult to evaluate. The late-type spiral majority of the sampl e spans a luminosity range MB−corr =−18 to −22 mag. Few of the E/S0 population are more luminous than−21.0 marking an absence of, an often sought, super L ∗ merger (e.g. fossil elliptical) population. The rarity of high lum inosity systems results in a fainter derived M ∗ for this population com- pared to the spiral optical luminosity function (OLF). The E-S0 population is from 0.2 to 0.6 mag fainter depending how the sample is defined. This marks the AMIGA sample as almost unique among samples that compare early and late-type OLFs sep- arately. In other samples, which always involve galaxies in higher density environments, M ∗/S0 is almost always 0.3-0.5 mag brighter than M ∗, presumably reflecting a stronger correlation between M ∗ and environmental density for early-type galaxies.

The AMIGA sample of isolated galaxies IV. A catalogue of neighbours around isolated galaxies

Context. Studies of the effects of environment on galaxy properties and evolution require well defined control samples. Such isolated galaxy samples have up to now been small or poorly defined. The AMIGA project (Analysis of the interstellar Medium of Isolated GAlaxies) represents an attempt to define a statistically useful sample of the most isolated galaxies in the local (z ≤ 0.05) Universe. Aims. A suitable large sample for the AMIGA project already exists, the Catalogue of Isolated Galaxies (CIG, Karachentseva, 1973, Astrofizicheskie Issledovaniia Izvestiya Spetsial’noj Astrofizicheskoj Observatorii, 8, 3; 1050 galaxies), and we use this sample as a starting point to refine and perform a better quantification of its isolation properties. Methods. Digitised POSS-I E images were analysed out to a minimum projected radius R ≥ 0.5 Mpc around 950 CIG galaxies (those within Vr = 1500 km s −1 were excluded). We identified all galaxy candidates in each field brighter than B = 17.5 with a high degree of confidence using the LMORPHO software. We generated a catalogue of approximately 54 000 potential neighbours (redshifts exist for ≈30% of this sample). Results. Six hundred sixty-six galaxies pass and two hundred eighty-four fail the original CIG isolation criterion. The available redshift data confirm that our catalogue involves a largely background population rather than physically associated neighbours. We find that the exclusion of neighbours within a factor of four in size around each CIG galaxy, employed in the original isolation criterion, corresponds to ∆Vr ≈ 18 000 km s −1 indicating that it was a conservative limit. Conclusions. Galaxies in the CIG have been found to show different degrees of isolation. We conclude that a quantitative measure of this is mandatory. It will be the subject of future work based on the catalogue of neighbours obtained here.

The AMIGA sample of isolated galaxies VI. Radio continuum properties of isolated galaxies : a very radio-quiet sample

Context. This paper is part of a series that describes the results of the AMIGA (Analysis of the interstellar Medium of Isolated GAlaxies) project, studying the largest sample of very isolated galaxies in the local Universe. Aims. The study of the radio properties of the AMIGA sample is intended to characterize the radio continuum emission for a sample least affected by the local environment, thus providing a reference against which less isolated and interacting samples can be compared. Methods. Radio continuum data at 325, 1420, and 4850 MHz were extracted from the WENSS, NVSS/FIRST, and GB6 surveys, respectively. The source extractions have been obtained from reprocessing the data and new detections added to the cross-matched detections with the respective survey catalogs. We focus on the complete AMIGA subsample composed of 719 galaxies. Results. A catalog of radio fluxes was obtained from the above four surveys. Comparison between the NVSS and FIRST detections indicates that the radio continuum is coming from disk-dominated emission in spiral galaxies, in contrast to the results found in high-density environments where nuclear activity is more frequent. The comparison of the radio continuum power with a comparable sample, which is however not selected with respect to its environment, the Condon et al. UGC-SF sample of starforming field galaxies, shows a lower mean value for the AMIGA sample. We have obtained radio-to-optical flux ratios (R) using the NVSS radio continuum flux. The distribution of R for the AMIGA galaxies is consistent with a sample dominated by radio emission from star formation (SF) and a small number of active galactic nuclei (AGN), with less than 3% of the sample with R > 100. We derived the radio luminosity function (RLF) and total power density of the radio continuum emission for the AMIGA sample at 1.4 GHz, and compared them with results from other low-redshift studies. The Schechter fit of the RLF indicates a major weight of the low-luminosity galaxies. Conclusions. The results indicate the very low level of radio continuum emission in our sample of isolated galaxies, which is dominated by mild disk SF. It confirms thus the AMIGA sample as a suitable template to effectively quantify the role of interactions in samples extracted from denser environments.

Virtual Observatory Activities in the AMIGA Group

The AMIGA (Analysis of the interstellar Medium of Isolated GAlaxies) project is an international collaboration led from the Instituto de Astrofisica de Andalucia (CSIC). The group’s experience in radio astronomy databases turned, as a natural evolution, into an active participation in the development of data archives and radio astronomy software. The contributions of the group to the Virtual Observatory (VO) have been mostly oriented towards the deployment of large VO compliant databases and the development of access interfaces (IRAM 30 m Pico Veleta, DSS–63 70 m in Robledo de Chavela). We also have been working in the development of an API for VO tools that will ease access to VO registries and communication between different VO software. A collaboration with the Kapteyn Astronomical Institute has started recently in order to perform a complete renovation of the only existing high-level software (GIPSY) for the analysis of datacubes, allowing its fully integration in the VO.

Building a VO-compliant Radio Astronomical DAta Model for Single-dish radio telescopes (RADAMS)

The Virtual Observatory (VO) is becoming the de-facto standard for astronomical data publication. However, the number of radio astronomical archives is still low in general, and even lower is the number of radio astronomical data available through the VO. In order to facilitate the building of new radio astronomical archives, easing at the same time their interoperability with VO framework, we have developed a VO-compliant data model which provides interoperable data semantics for radio data. That model, which we call the Radio Astronomical DAta Model for Single-dish (RADAMS) has been built using standards of (and recommendations from) the International Virtual Observatory Alliance (IVOA). This article describes the RADAMS and its components, including archived entities and their relationships to VO metadata. We show that by using IVOA principles and concepts, the effort needed for both the development of the archives and their VO compatibility has been lowered, and the joint development of two radio astronomical archives have been possible. We plan to adapt RADAMS to be able to deal with interferometry data in the future.

ISM of Galaxies in Extremely Different Environments: Isolated vs Compact Groups

1 Instituto de Astrofisica de Andalucia, CSIC, Apdo. 3004, 18080 Granada, Spain lourdes@iaa.es,daniel@iaa.es,gilles@iaa.es,garcia@iaa.es,jsm@iaa.es, simon@iaa.es 2 Department of Astronomy, University of Massachussetts, Amherst, MA 01003, USA myun@bonito.astro.umass.edu,sanchayeeta-lg@yahoo.com 3 National Research Institute of Astronomy and Geophysics, Cairo Egypt ibrahimselim@hotmail.com 4 Observatoire de Marseille, 2 Place le Verrier, 13248 Marseille Cedez 4, France lia@oamp.fr,bosma@oamp.fr 5 LERMA, Observatoire de Paris, 61 Av. de l’Observatoire, 75014 Paris, France Simon.Verley@obspm.fr 6 Max-Planck-Institut fur Radiostronomie, Auf dem Hugel 69, 53121 Bonn, Germany p083huc@mpifr-bonn.mpg.de 7 Departamento de Fisica Teorica y del Cosmos, Facultad de Ciencias, Universidad de Granada, Spain ute@ugr.es 8 sco@astro.as.utexas.edu 9 tjp@xun0.sr.bham.ac.uk,jesper@star.sr.bham.ac.uk 10 Department of Astronomy, Univ. of Alabama, AL 35487, USA giacomo@merlot.astr.ua.edu

Design and Control of a Manipulator for Landmine Detection

Antipersonnel mines infest fields all over the world. According to recent estimates, landmines are killing and maiming more than 2,000 innocent civilians per month [1]. The problem of landmine detection and removal requires the cooperation of various engineering fields. For this purpose, new technologies such as improved sensors, efficient manipulators and mobile robots are needed. This paper describes the configuration and control architecture of a scanning manipulator to detect antipersonnel landmines. The main features of the system that consists of a sensor head able to detect some kind of landmines and a manipulator to move the sensor head over large areas, conveniently sensorized to scan irregular terrains in the presence of obstacles are presented. Experiments show the performance of the whole system.