77 research outputs found
HI asymmetry in the isolated galaxy CIG 85 (UGC 1547)
We present the results from the Giant Metrewave Radio Telescope (GMRT)
interferometric HI and 20 cm radio continuum observations of CIG 85, an
isolated asymmetric galaxy from the AMIGA (Analysis of the Interstellar Medium
of Isolated GAlaxies) sample. Despite being an isolated galaxy, CIG 85 showed
an appreciable optical and HI spectral asymmetry and therefore was an excellent
candidate for resolved HI studies to understand the reasons giving rise to
asymmetries in isolated galaxies. The galaxy was imaged in HI and 20 cm radio
continuum using the GMRT. For a detailed discussion of the results we also made
use of multi-wavelength data from archival SDSS, GALEX and Halpha imaging. We
find the HI in CIG 85 to have a clumpy, asymmetric distribution which in the NW
part is correlated with optical tail like features, but the HI velocity field
displays a relatively regular rotation pattern. Evaluating all the
observational evidence, we come to a conclusion that CIG 85 is most likely a
case of a disturbed spiral galaxy which now appears to have the morphology of
an irregular galaxy. Although it is currently isolated from major companions,
the observational evidence is consistent with HI asymmetries, a highly
disturbed optical disk and recent increase in star formation having been caused
by a minor merger, remnants of which are now projected in front of the optical
disk. If this is correct, the companion will be fully accreted by CIG 85 in the
near future.Comment: 10 pages, 9 figures, accepted in A&
Effects of the environment on galaxies in the Catalogue of Isolated Galaxies: physical satellites and large scale structure
We aim to identify and quantify the effects of the satellite distribution
around a sample of galaxies in the Catalogue of Isolated Galaxies (CIG), as
well as the effects of the Large Scale Structure (LSS) using the SDSS-DR9. To
recover the physically bound galaxies we focus on the satellites which are
within the escape speed of each CIG galaxy. We also propose a more conservative
method using the stacked Gaussian distribution of the velocity difference of
the neighbours. The tidal strengths affecting the primary galaxy are estimated
to quantify the effects of the local and LSS environments. We also define the
projected number density parameter at the 5 nearest neighbour to
characterise the LSS around the CIG galaxies. Out of the 386 CIG galaxies
considered in this study, at least 340 (88\% of the sample) have no physically
linked satellite. Out of the 386 CIG galaxies, 327 (85\% of the sample) have no
physical companion within a projected distance of 0.3 Mpc. The CIG galaxies are
distributed following the LSS of the local Universe, although presenting a
large heterogeneity in their degree of connection with it. A clear segregation
appears between early-type CIG galaxies with companions and isolated late-type
CIG galaxies. Isolated galaxies are in general bluer, with likely younger
stellar populations and rather high star formation with respect to older,
redder CIG galaxies with companions. Reciprocally, the satellites are redder
and with an older stellar populations around massive early-type CIG galaxies,
while they have a younger stellar content around massive late-type CIG
galaxies. This suggests that the CIG is composed of a heterogeneous population
of galaxies, sampling from old to more recent, dynamical systems of galaxies.Comment: 19 pages, 10 figures, 1 table, accepted for publication in Astronomy
& Astrophysic
Hemangiosarcoma pulmonar primario en un Pastor Alemán con neumotórax espontáneo
Se describe un caso clínico de un hemangiosarcoma (HSA) primario pulmonar, en un pastor alemán, evaluado por un cuadro agudo de disnea asociado a un neumotórax espontáneo.
The AMIGA sample of isolated galaxies XI. A First Look at Isolated Galaxy Colors
The basic properties of galaxies can be affected by both nature (internal
processes) or nurture (interactions and effects of environment). Deconvolving
the two effects is an important current effort in astrophysics. Observed
properties of a sample of isolated galaxies should be largely the result of
internal (natural) evolution. It follows that nurture-induced galaxy evolution
can only be understood through comparative study of galaxies in different
environments. We take a first look at SDSS (g-r) colors of galaxies in the
AMIGA sample involving many of the most isolated galaxies in the local
Universe. This leads us to simultaneously consider the pitfalls of using
automated SDSS colors. We focus on median values for the principal
morphological subtypes found in the AMIGA sample (E/S0 and Sb-Sc) and compare
them with equivalent measures obtained for galaxies in denser environments. We
find a weak tendency for AMIGA spiral galaxies to be redder than objects in
close pairs. We find no clear difference when we compare with galaxies in other
(e.g. group) environments. However, the (g-r) color of isolated galaxies shows
a Gaussian distribution as might be expected assuming nurture-free evolution.
We find a smaller median absolute deviation in colors for isolated galaxies
compared to both wide and close pairs. The majority of the deviation on median
colors for spiral subtypes is caused by a color-luminosity correlation.
Surprisingly isolated and non-isolated early-type galaxies show similar (g-r).
We see little evidence for a green valley in our sample with most spirals
redder than (g-r)=0.7 having spurious colors. The redder colors of AMIGA
spirals and lower color dispersions for AMIGA subtypes -compared with close
pairs- is likely due to a more passive star formation in very isolated
galaxies.Comment: Accepted for publication in A&A. 9 pages, 7 Figures, and 2 tables,
one only available onlin
The AMIGA sample of isolated galaxies. XI. Optical characterisation of nuclear activity
Context.- This paper is part of a series involving the AMIGA project
(Analysis of the Interstellar Medium of Isolated GAlaxies), which identifies
and studies a statistically-significant sample of the most isolated galaxies in
the northern sky. Aims.- We present a catalogue of nuclear activity, traced by
optical emission lines, in a well-defined sample of the most isolated galaxies
in the local Universe, which will be used as a basis for studying the effect of
the environment on nuclear activity. Methods.- We obtained spectral data from
the 6th Data Release of the Sloan Digital Sky Survey, which were inspected in a
semi-automatic way. We subtracted the underlying stellar populations from the
spectra (using the software Starlight) and modelled the nuclear emission
features. Standard emission-line diagnostics diagrams were applied, using a new
classification scheme that takes into account censored data, to classify the
type of nuclear emission. Results.- We provide a final catalogue of
spectroscopic data, stellar populations, emission lines and classification of
optical nuclear activity for AMIGA galaxies. The prevalence of optical active
galactic nuclei (AGN) in AMIGA galaxies is 20.4%, or 36.7% including transition
objects. The fraction of AGN increases steeply towards earlier morphological
types and higher luminosities. We compare these results with a matched analysis
of galaxies in isolated denser environments (Hickson Compact Groups). After
correcting for the effects of the morphology and luminosity, we find that there
is no evidence for a difference in the prevalence of AGN between isolated and
compact group galaxies, and we discuss the implications of this result.
Conclusions.- We find that a major interaction is not a necessary condition for
the triggering of optical AGN.Comment: 16 pages, 11 figures, 12 tables, published in Astronomy and
Astrophysics. Figure 5 corrected: [OI] diagram adde
Does the LFIR-LHCN correlation hold for low LFIR isolated galaxies?
International conference “Galaxies in Isolation: Exploring Nature vs. Nurture” held in Granada (Spain), May 12–15, 2009.Low LFIR Isolated Galaxies (IGs) from the AMIGA sample have
low level of Star Formation (SF) activity. We observed the HCN(1-0) emission
in a sample of IGs in order to test whether they follow the tight relation between
LHCN and LFIR found for galaxies with more active SF
Knowledge, Attitudes, and Beliefs About Human Papillomavirus (HPV) Vaccination Among Puerto Rican Mothers and Daughters, 2010: A Qualitative Study
IntroductionThe incidence of human papillomavirus (HPV) infection and cervical cancer can be reduced by increasing vaccination for HPV. Yet vaccination uptake and completion of the 3-dose series remain low among Puerto Rican females. This study explored psychosocial factors associated with HPV vaccination uptake decisions among Puerto Rican mothers and daughters.MethodsWe conducted 7 focus groups with young women aged 16 to 24 (n = 21) and their mothers (n = 9) to assess knowledge, attitudes, and beliefs related to cervical cancer, HPV, and HPV vaccination. We analyzed the focus group transcripts and identified themes by using a constant comparison method of qualitative data analysis and interpretation, guided by a grounded theory approach.ResultsThe analysis identified several emergent themes related to vaccine uptake: 1) low knowledge about cervical cancer, HPV, and the HPV vaccine; 2) inconsistent beliefs about susceptibility to HPV infection and cervical cancer; 3) vaccine effectiveness; 4) vaccine safety and side effects; 5) concerns that the vaccine promotes sexual disinhibition; and 6) availability of insurance coverage and overall cost of the vaccine.ConclusionOur study found that adolescent girls and young women in Puerto Rico have low levels of knowledge about HPV and cervical cancer, low perceived susceptibility to HPV, and concerns about the safety and efficacy of the vaccine, and these factors may influence uptake and completion of HPV vaccination. Interventions are needed for both mothers and daughters that address these psychosocial factors and increase access to vaccination
Unveiling the environment and faint features of the isolated galaxy CIG 96 with deep optical and HI observations
AbstractContext: Asymmetries in atomic hydrogen (HI) in galaxies are often caused by the interaction with close companions, making isolated galaxies an ideal framework to study secular evolution. The AMIGA project has demonstrated that isolated galaxies show the lowest level of asymmetry in their HI integrated profiles compared to even field galaxies, yet some present significant asymmetries. CIG 96 (NGC 864) is a representative case reaching a 16% level.Aims: Our aim is to investigate the HI asymmetries of the spiral galaxy CIG 96 and what processes have triggered the star-forming regions observed in the XUV pseudo-ring.Methods: We performed deep optical observations at CAHA1.23m, CAHA2.2m and VST (OmegaCAM wide-field camera) telescopes. We reach surface brightness (SB) limits of μCAHA2.2m = 27.5 mag arcsec⁻² (Cousins R) and μVST = 28.7 mag arcsec⁻² (SDSS r) that show the XUV pseudo-ring of the galaxy 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), lower than in any isolated galaxy.Results: We confirm that the HI of CIG 96 extends farther than 4 × r₂₅ in all directions. Furthermore, we detect for the first time two gaseous structures (∼10⁶ M⊙) in the outskirts. The SDSS g - r colour index image from CAHA1.23m shows extremely blue colours in certain regions of the pseudo-ring where NHI > 8.5 × 10²⁰ cm⁻², whereas the rest show red colours. Galactic cirrus contaminate the field, setting an unavoidable detection limit at 28.5 mag arcsec⁻² (SDSS r).Conclusions: At the current SB and NHI levels, we detect no stellar link within 1° × 1° or 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 pseudo-ring is estimated at 1 Gyr or older. Undetected previously accreted companions and cold gas accretion remain as the main hypothesis to explain the optical pseudo-ring and HI features of CIG 96.Abstract
Context: Asymmetries in atomic hydrogen (HI) in galaxies are often caused by the interaction with close companions, making isolated galaxies an ideal framework to study secular evolution. The AMIGA project has demonstrated that isolated galaxies show the lowest level of asymmetry in their HI integrated profiles compared to even field galaxies, yet some present significant asymmetries. CIG 96 (NGC 864) is a representative case reaching a 16% level.
Aims: Our aim is to investigate the HI asymmetries of the spiral galaxy CIG 96 and what processes have triggered the star-forming regions observed in the XUV pseudo-ring.
Methods: We performed deep optical observations at CAHA1.23m, CAHA2.2m and VST (OmegaCAM wide-field camera) telescopes. We reach surface brightness (SB) limits of μCAHA2.2m = 27.5 mag arcsec⁻² (Cousins R) and μVST = 28.7 mag arcsec⁻² (SDSS r) that show the XUV pseudo-ring of the galaxy 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), lower than in any isolated galaxy.
Results: We confirm that the HI of CIG 96 extends farther than 4 × r₂₅ in all directions. Furthermore, we detect for the first time two gaseous structures (∼10⁶ M⊙) in the outskirts. The SDSS g - r colour index image from CAHA1.23m shows extremely blue colours in certain regions of the pseudo-ring where NHI > 8.5 × 10²⁰ cm⁻², whereas the rest show red colours. Galactic cirrus contaminate the field, setting an unavoidable detection limit at 28.5 mag arcsec⁻² (SDSS r).
Conclusions: At the current SB and NHI levels, we detect no stellar link within 1° × 1° or 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 pseudo-ring is estimated at 1 Gyr or older. Undetected previously accreted companions and cold gas accretion remain as the main hypothesis to explain the optical pseudo-ring and HI features of CIG 96
Morphologies of galaxies within voids
Context. Among the largest structures in which matter is distributed in the Universe, we find cosmic voids, which are large, under-dense regions almost devoid of galaxies. The study of these structures and the galaxies that inhabit them, the void galaxies, provides key information for understanding galaxy evolution.Aims. In this work we investigate the effects of the environment on the evolution of void galaxies. In particular, we study their morphology and explore its dependence on the location within the void where the galaxies reside, as well as on the properties of the void, such as its size and the galaxy number density.Methods. The sample of void galaxies that we use in this study is based on the catalogue of cosmic voids and void galaxies in the Sloan Digital Sky Survey Data Release 7 (SDSS-DR7). As we are interested in studying the morphology of void galaxies, we select galaxies in the redshift range of 0.005 ≤ z ≤ 0.080, and use the public galaxy morphologies of the SDSS sample together with deep learning algorithms to divide the sample into early- and late-type void galaxies. We analyse the fractions of galaxies of each morphological type as a function of the void-centric distance, the size of the voids, and the density of galaxies in each void.Results. There is a higher abundance of late-type galaxies with respect to early-type galaxies within voids, which remains nearly constant from the inner to the outer part of the voids. We do not find any dependence of the fraction of early- and late-type galaxies on void size or on the number-density of galaxies in the voids.Conclusions. Galaxies in voids follow the morphology–density relation, in the sense that the majority of the galaxies in voids (the most under-dense large-scale environments) are late-type galaxies. However, we find no difference between voids with lower or higher volume number-density of galaxies: the fractions of early- and late-type galaxies do not depend on the density of the voids. The physical processes responsible for the evolution from late towards earlier types (such as external environmental quenching) are not sufficiently effective in voids or are so slow (internal secular quenching) that their contributions do not appear in the morphology–density relation. © The Authors 2024The authors thank the anonymous referee for the thorough reading and constructive feedback. This paper is partially based on data obtained by the CAVITY project, funded by the Spanish Ministry of Science and Innovation under grants PID2020-113689GB-I00 and PID2023.149578NB.I00 as well as by Consejería de Universidad, Investigación e Innovación and Gobierno de España and Unión Europea – NextGenerationEU through grant AST22_4.4. We acknowledge financial support by the research project PID2020-114414GB-I00, financed by MCIN/AEI/10.13039/501100011033, the project A-FQM-510-UGR20 financed from FEDER/Junta de Andalucía-Consejería de Transforamción Económica, Industria, Conocimiento y Universidades/Proyecto and by the grants P20_00334 and FQM108, financed by the Junta de Andalucía (Spain). M.A-F. acknowledges support from ANID FONDECYT iniciación project 11200107 and the Emergia program (EMERGIA20_38888) from Consejería de Universidad, Investigación e Innovación de la Junta de Andalucía. S.D.P. acknowledges financial support from Juan de la Cierva Formación fellowship (FJC2021-047523-I) financed by MCIN/AEI/10.13039/501100011033 and by the European Union “NextGenerationEU”/PRTR, Ministerio de Economía y Competitividad under grant PID2019-107408GB-C44 and PID2022-136598NB-C32, and also from the Fonds de Recherche du Québec – Nature et Technologies. DE acknowledges support from a Beatriz Galindo senior fellowship (BG20/00224) from the Spanish Ministry of Science and Innovation. LSM acknowledges support from Juan de la Cierva fellowship (IJC2019-041527-I). Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the U.S. Department of Energy Office of Science. The SDSS-III web site is http://www.sdss3.org/. SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration including the University of Arizona, the Brazilian Participation Group, Brookhaven National Laboratory, Carnegie Mellon University, University of Florida, the French Participation Group, the German Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for Extraterrestrial Physics, New Mexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington, and Yale University. This research made use of Astropy, a community-developed core Python (http://www.python.org) package for Astronomy (Astropy Collaboration 2013, 2018); ipython (Pérez & Granger 2007); matplotlib (Hunter 2007); SciPy, a collection of open source software for scientific computing in Python (Virtanen et al. 2020); pandas, an open source data analysis and manipulation tool (pandas development team 2020; Wes McKinney 2010); and NumPy, a structure for efficient numerical computation (van der Walt et al. 2011).Peer reviewe
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