130 research outputs found
Spectroscopy of Ultra-diffuse Galaxies in the Coma Cluster
We present spectra of 5 ultra-diffuse galaxies (UDGs) in the vicinity of the
Coma Cluster obtained with the Multi-Object Double Spectrograph on the Large
Binocular Telescope. We confirm 4 of these as members of the cluster,
quintupling the number of spectroscopically confirmed systems. Like the
previously confirmed large (projected half light radius 4.6 kpc) UDG, DF44,
the systems we targeted all have projected half light radii kpc. As
such, we spectroscopically confirm a population of physically large UDGs in the
Coma cluster. The remaining UDG is located in the field, about Mpc behind
the cluster. We observe Balmer and Ca II H \& K absorption lines in all of our
UDG spectra. By comparing the stacked UDG spectrum against stellar population
synthesis models, we conclude that, on average, these UDGs are composed of
metal-poor stars ([Fe/H] ). We also discover the first UDG with
[OII] and [OIII] emission lines within a clustered environment, demonstrating
that not all cluster UDGs are devoid of gas and sources of ionizing radiation.Comment: 5 pages, 4 figure
Pornography: Social Science, Legal, and Clinical Perspectives
Symposium: Seventh Annual Conference of the National Association of Women Judges: Conference Presentation
Pornography: Social Science, Legal, and Clinical Perspectives
Symposium: Seventh Annual Conference of the National Association of Women Judges: Conference Presentation
WALLABY pre-pilot survey: ultra-diffuse galaxies in the Eridanus supergroup
We present a pilot study of the atomic neutral hydrogen gas (H I) content of ultra-diffuse galaxy (UDG) candidates. In this paper, we use the pre-pilot Eridanus field data from the Widefield ASKAP L-band Legacy All-sky Blind Survey to search for H I in UDG candidates found in the Systematically Measuring Ultra-diffuse Galaxies survey (SMUDGes). We narrow down to 78 SMUDGes UDG candidates within the maximum radial extents of the Eridanus subgroups for this study. Most SMUDGes UDGs candidates in this study have effective radii smaller than 1.5 kpc and thus fail to meet the defining size threshold. We only find one H I detection, which we classify as a low-surface-brightness dwarf. Six putative UDGs are H I-free. We show the overall distribution of SMUDGes UDG candidates on the size–luminosity relation and compare them with low-mass dwarfs on the atomic gas fraction versus stellar mass scaling relation. There is no correlation between gas-richness and colour indicating that colour is not the sole parameter determining their H I content. The evolutionary paths that drive galaxy morphological changes and UDG formation channels are likely the additional factors to affect the H I content of putative UDGs. The actual numbers of UDGs for the Eridanus and NGC 1332 subgroups are consistent with the predicted abundance of UDGs and the halo virial mass relation, except for the NGC 1407 subgroup, which has a smaller number of UDGs than the predicted number. Different group environments suggest that these putative UDGs are likely formed via the satellite accretion scenario. © 2023 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical SocietyThis research was supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. This scientific work uses data obtained from Inyarrimanha Ilgari Bundara/the Murchison Radio-astronomy Observatory. We acknowledge the Wajarri Yamaji People as the Traditional Owners and native title holders of the Observatory site. CSIRO's ASKAP radio telescope is part of the Australia Telescope National Facility (https://ror.org/05qajvd42). Operation of ASKAP is funded by the Australian Government with support from the National Collaborative Research Infrastructure Strategy. ASKAP uses the resources of the Pawsey Supercomputing Research Centre. Establishment of ASKAP, Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-astronomy Observatory, and the Pawsey Supercomputing Research Centre are initiatives of the Australian Government, with support from the Government of Western Australia and the Science and Industry Endowment Fund. This research has made use of images of the Legacy Surveys. The Legacy Surveys consist of three individual and complementary projects: (DECaLS; Proposal ID #2014B-0404; PIs: David Schlegel and Arjun Dey), the Beijing-Arizona Sky Survey (BASS; NOAO Prop. ID #2015A-0801; PIs: Zhou Xu and Xiaohui Fan), and the Mayall z-band Legacy Survey (MzLS; Prop. ID #2016A-0453; PI: Arjun Dey). DECaLS, BASS, and MzLS together include data obtained, respectively, at the Blanco telescope, Cerro Tololo Inter-American Observatory, NSF's NOIRLab; the Bok telescope, Steward Observatory, University of Arizona, and the Mayall telescope, Kitt Peak National Observatory, NOIRLab. The Legacy Surveys project is honoured to be permitted to conduct astronomical research on Iolkam Du'ag (Kitt Peak), a mountain with particular significance to the Tohono O'odham Nation. We thank the anonymous referee for their constructive comments to improve this manuscript. BQF thanks A. Bosma, A. Boselli, B. Holwerda, A. Lopez-Sanchez, K. McQuinn, G. Muerer, J. Roman, and P. Zuo for their comments on the manuscript. KS acknowledges support from the Natural Sciences and Engineering Research Council of Canada (NSERC). AK acknowledges financial support from the grant CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033 and from the grant POSTDOC_21_00845 funded by the Economic Transformation, Industry, Knowledge and Universities Council of the Regional Government of Andalusia and financial support from the grant PID2021-123930OB-C21 funded by MCIN/AEI/10.13039/501100011033, by 'ERDF A way of making Europe' and by the 'European Union'. DZ and RD gratefully acknowledge financial support for SMUDGes from NSF AST-1713841 and AST-2006785. DZ thanks the Astronomy Department at Columbia University for their gracious welcome during his sabbatical
Implications for galaxy formation models from observations of globular clusters around ultradiffuse galaxies
We present an analysis of Hubble Space Telescope observations of globular clusters (GCs) in six ultradiffuse galaxies (UDGs) in the Coma cluster, a sample that represents UDGs with large effective radii (Re), and use the results to evaluate competing formation models. We eliminate two significant sources of systematic uncertainty in the determination of the number of GCs, NGC by using sufficiently deep observations that (i) reach the turnover of the globular cluster luminosity function (GCLF) and (ii) provide a sufficient number of GCs with which to measure the GC number radial distribution. We find that NGC for these galaxies is on average ∼ 20, which implies an average total mass, Mtotal, ∼ 1011 M⊙ when applying the relation between NGC and Mtotal. This value of NGC lies at the upper end of the range observed for dwarf galaxies of the same stellar mass and is roughly a factor of two larger than the mean. The GCLF, radial profile, and average colour are more consistent with those observed for dwarf galaxies than with those observed for the more massive (L*) galaxies, while both the radial and azimuthal GC distributions closely follow those of the stars in the host galaxy. Finally, we discuss why our observations, specifically the GC number and GC distribution around these six UDGs, pose challenges for several of the currently favoured UDG formation models
KIMA: Noise: A visual sound installation on urban noise
KIMA: Noise is a participatory art piece inviting audiences to explore impact of urban noises interactively. Using specific urban sound sources, the audience experiences noise as spatial soundscapes, responding to it, physically engaging and interacting with it. KIMA: Noise creates awareness for the phenomenon of noise pollution. The paper looks at preeminent research in the field, and draws conclusions of how sound affects us as individuals. The art project KIMA: Noise is introduced technically and conceptually
One hundred SMUDGes in S-PLUS: ultra-diffuse galaxies flourish in the field
We present the first systematic study of the stellar populations of ultra-diffuse galaxies (UDGs) in the field, integrating the large area search and characterization of UDGs by the SMUDGes survey with the twelve-band optical photometry of the S-PLUS survey. Based on Bayesian modeling of the optical colors of UDGs, we determine the ages, metallicities and stellar masses of 100 UDGs distributed in an area of deg in the Stripe 82 region. We find that the stellar masses and metallicities of field UDGs are similar to those observed in clusters and follow the trends previously defined in studies of dwarf and giant galaxies. However, field UDGs have younger luminosity-weighted ages than do UDGs in clusters. We interpret this result to mean that field UDGs have more extended star formation histories, including some that continue to form stars at low levels to the present time. Finally, we examine stellar population scaling relations that show that UDGs are, as a population, similar to other low-surface brightness galaxies.Instituto de Astrofísica de La PlataFacultad de Ciencias Astronómicas y Geofísica
Sexual Priming, Gender Stereotyping, and Likelihood to Sexually Harass: Examining the Cognitive Effects of Playing a Sexually-Explicit Video Game
The present study examines the short-term cognitive effects of playing a sexually explicit video game with female “objectification” content on male players. Seventy-four male students from a university in California, U.S. participated in a laboratory experiment. They were randomly assigned to play either a sexually-explicit game or one of two control games. Participants’ cognitive accessibility to sexual and sexually objectifying thoughts was measured in a lexical decision task. A likelihood-to-sexually-harass scale was also administered. Results show that playing a video game with the theme of female “objectification” may prime thoughts related to sex, encourage men to view women as sex objects, and lead to self-reported tendencies to behave inappropriately towards women in social situations
“Shake It Baby, Shake It”: Media Preferences, Sexual Attitudes and Gender Stereotypes Among Adolescents
In this study exposure to and preferences for three important youth media (TV, music styles/music TV, internet) were examined in relation to adolescents’ permissive sexual attitudes and gender stereotypes (i.e., views of men as sex-driven and tough, and of women as sex objects). Multivariate structural analysis of data from a school-based sample of 480 13 to 16-year-old Dutch students revealed that preferences, rather than exposure were associated with attitudes and stereotypes. For both girls and boys, preferences for hip-hop and hard-house music were associated positively with gender stereotypes and preference for classical music was negatively associated with gender stereotypes. Particularly for boys, using internet to find explicit sexual content emerged as a powerful indicator of all attitudes and stereotypes
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