Globular Cluster Clustering and Tidal Features Around Ultra-Compact Dwarf Galaxies in the Halo of NGC 1399?
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A Revised View of the Canis Major Stellar Overdensity with Decam And
MNRAS 501, 1690–1700 (2021) doi:10.1093/mnras/staa2655 Advance Access publication 2020 October 14 A revised view of the Canis Major stellar overdensity with DECam and Gaia: new evidence of a stellar warp of blue stars Downloaded from https://academic.oup.com/mnras/article/501/2/1690/5923573 by Consejo Superior de Investigaciones Cientificas (CSIC) user on 15 March 2021 Julio A. Carballo-Bello ,1‹ David Mart´ınez-Delgado,2 Jesus´ M. Corral-Santana ,3 Emilio J. Alfaro,2 Camila Navarrete,3,4 A. Katherina Vivas 5 and Marcio´ Catelan 4,6 1Instituto de Alta Investigacion,´ Universidad de Tarapaca,´ Casilla 7D, Arica, Chile 2Instituto de Astrof´ısica de Andaluc´ıa, CSIC, E-18080 Granada, Spain 3European Southern Observatory, Alonso de Cordova´ 3107, Casilla 19001, Santiago, Chile 4Millennium Institute of Astrophysics, Santiago, Chile 5Cerro Tololo Inter-American Observatory, NSF’s National Optical-Infrared Astronomy Research Laboratory, Casilla 603, La Serena, Chile 6Instituto de Astrof´ısica, Facultad de F´ısica, Pontificia Universidad Catolica´ de Chile, Av. Vicuna˜ Mackenna 4860, 782-0436 Macul, Santiago, Chile Accepted 2020 August 27. Received 2020 July 16; in original form 2020 February 24 ABSTRACT We present the Dark Energy Camera (DECam) imaging combined with Gaia Data Release 2 (DR2) data to study the Canis Major overdensity. The presence of the so-called Blue Plume stars in a low-pollution area of the colour–magnitude diagram allows us to derive the distance and proper motions of this stellar feature along the line of sight of its hypothetical core. The stellar overdensity extends on a large area of the sky at low Galactic latitudes, below the plane, and in the range 230◦ <<255◦. -
R" ^ the Astrophysical Journal, 369:79-105,1991
O'! r" ^ The Astrophysical Journal, 369:79-105,1991 March 1 © 1991. The American Astronomical Society. All rights reserved. Printed in U.S.A. O'! \O'! 1 A DEEP IMAGING AND SPECTROSCOPIC SURVEY OF FAINT GALAXIES S. J. Lilly,1 L. L. Cowie,1 and J. P. Gardner1 Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 Received 1990 May 9 ; accepted 1990 August 22 ABSTRACT The results of a deep imaging and spectroscopic optical survey are presented. Three small areas of sky at 13 h, 17 h, and 22 h have been imaged to faint levels in four passbands (U', B, V, and I) in the optical window. These reach approximately 27th magnitude for galaxy images, at which point the surface density of galaxies is 5 -2 roughly 2.5 x 10 deg . A complete catalog of objects to JAB ~ 24.5 is provided as the basis for future studies of the faint extragalactic population. Spectroscopic observations of a small but essentially complete sample of galaxies in and around the 22 h field have yielded redshifts for a high fraction of galaxies with Bab <24.1. Detailed comparison of our deep images with similar data from other observers shows some broad similarities but also some significant differences. In particular, our faintest galaxies are in general con- siderably redder, and the fraction of galaxies with colors that are unrepresentable by normal galaxies is corre- spondingly much smaller. We also see evidence for a decline in the steep slope of the B-band number counts for magnitudes fainter than B ~ 24. -
The Milky Way's Disk of Classical Satellite Galaxies in Light of Gaia
MNRAS 000,1{20 (2019) Preprint 14 November 2019 Compiled using MNRAS LATEX style file v3.0 The Milky Way's Disk of Classical Satellite Galaxies in Light of Gaia DR2 Marcel S. Pawlowski,1? and Pavel Kroupa2;3 1Leibniz-Institut fur¨ Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam, Germany 2Helmholtz-Institut fur¨ Strahlen- und Kernphysik, University of Bonn, Nussallee 14-16, D- 53115 Bonn, Germany 3Charles University in Prague, Faculty of Mathematics and Physics, Astronomical Institute, V Holeˇsoviˇck´ach 2, CZ-180 00 Praha 8, Czech Republic Accepted 2019 November 7. Received 2019 November 7; in original form 2019 August 26 ABSTRACT We study the correlation of orbital poles of the 11 classical satellite galaxies of the Milky Way, comparing results from previous proper motions with the independent data by Gaia DR2. Previous results on the degree of correlation and its significance are confirmed by the new data. A majority of the satellites co-orbit along the Vast Polar Structure, the plane (or disk) of satellite galaxies defined by their positions. The orbital planes of eight satellites align to < 20◦ with a common direction, seven even orbit in the same sense. Most also share similar specific angular momenta, though their wide distribution on the sky does not support a recent group infall or satellites- of-satellites origin. The orbital pole concentration has continuously increased as more precise proper motions were measured, as expected if the underlying distribution shows true correlation that is washed out by observational uncertainties. The orbital poles of the up to seven most correlated satellites are in fact almost as concentrated as expected for the best-possible orbital alignment achievable given the satellite posi- tions. -
A Dusty, Normal Galaxy in the Epoch of Reionization
A dusty, normal galaxy in the epoch of reionization Darach Watson1, Lise Christensen1, Kirsten Kraiberg Knudsen2, Johan Richard3, Anna Gallazzi4,1, and Michał Jerzy Michałowski5 Candidates for the modest galaxies that formed most of the stars in the early universe, at redshifts z > 7, have been found in large numbers with extremely deep restframe-UV imaging1. But it has proved difficult for existing spectrographs to characterise them in the UV2,3,4. The detailed properties of these galaxies could be measured from dust and cool gas emission at far-infrared wavelengths if the galaxies have become sufficiently enriched in dust and metals. So far, however, the most distant UV-selected galaxy detected in dust emission is only at z = 3.25, and recent results have cast doubt on whether dust and molecules can be found in typical galaxies at this early epoch6,7,8. Here we report thermal dust emission from an archetypal early universe star-forming galaxy, A1689-zD1. We detect its stellar continuum in spectroscopy and determine its redshift to be z = 7.5±0.2 from a spectroscopic detection of the Lyα break. A1689-zD1 is representative of the star-forming population during reionisation9, with a total star- –1 formation rate of about 12 M yr . The galaxy is highly evolved: it has a large stellar mass, and is heavily enriched in dust, with a dust-to-gas ratio close to that of the Milky Way. Dusty, evolved galaxies are thus present among the fainter star-forming population at z > 7, in spite of the very short time since they first appeared. -
VI. Star-Forming Companions of Nearby Field Galaxies
A&A 486, 131–142 (2008) Astronomy DOI: 10.1051/0004-6361:20079297 & c ESO 2008 Astrophysics The Hα Galaxy Survey VI. Star-forming companions of nearby field galaxies P. A. James1, J. O’Neill2, and N. S. Shane1,3 1 Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD, UK e-mail: [email protected] 2 Wirral Grammar School for Girls, Heath Road, Bebington, Wirral CH63 3AF, UK 3 Planetary Science Group, Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK Received 20 December 2007 / Accepted 5 May 2008 ABSTRACT Aims. We searched for star-forming satellite galaxies that are close enough to their parent galaxies to be considered analogues of the Magellanic Clouds. Methods. Our search technique relied on the detection of the satellites in continuum-subtracted narrow-band Hα imaging of the central galaxies, which removes most of the background and foreground line-of-sight companions, thus giving a high probability that we are detecting true satellites. The search was performed for 119 central galaxies at distances between 20 and 40 Mpc, although spatial incompleteness means that we have effectively searched 53 full satellite-containing volumes. Results. We find only 9 “probable” star-forming satellites, around 9 different central galaxies, and 2 more “possible” satellites. After incompleteness correction, this is equivalent to 0.17/0.21 satellites per central galaxy. This frequency is unchanged whether we consider all central galaxy types or just those of Hubble types S0a–Sc, i.e. only the more luminous and massive spiral types. -
Publications of the Astronomical Society of the Pacific Vol. 109 1997
Publications of the Astronomical Society of the Pacific Vol. 109 1997 July No. 737 Publications of the Astronomical Society of the Pacific 109: 745-758, 1997 July Invited Review Paper Low-Surface-Brightness Galaxies: Hidden Galaxies Revealed Greg Bothun Department of Physics, University of Oregon, Eugene, Oregon 97403 Electronic mail: [email protected] Chris Impey Steward Observatory, University of Arizona, Tucson, Arizona 85721 Electronic mail: [email protected] Stacy McGaugh Department of Terrestrial Magnetism, Carnegie Institution of Washington, DC 20005 Electronic mail: [email protected] Received 1997 February 12; accepted 1997 April 29 ABSTRACT. In 20 years, low-surface-brightness (LSB) galaxies have evolved from being an idiosyncratic notion to being one of the major baryonic repositories in the Universe. The story of their discovery and the characterization of their properties is told here. Their recovery from the noise of the night-sky background is a strong testament to the severity of surface-brightness selection effects. LSB galaxies have a number of remarkable properties which distinguish them from the more familiar Hubble sequence of spirals. The two most important are (1) they evolve at a significantly slower rate and may well experience star formation outside of the molecular-cloud environment, (2) they are embedded in dark-matter halos which are of lower density and more extended than the halos around high-surface-brightness (HSB) disk galaxies. Compared to HSB disks, LSB disks are strongly dark-matter dominated at all radii and show a systematic increase in M/L with decreasing central surface brightness. In addition, the recognition that large numbers of LSB galaxies actually exist has changed the form of the galaxy luminosity function and has clearly increased the space density of galaxies at ζ = 0. -
Carnegie Institution of Washington Department of Terrestrial Magnetism Washington, DC 20015-1305
43 Carnegie Institution of Washington Department of Terrestrial Magnetism Washington, DC 20015-1305 This report covers astronomical research carried out during protostellar outflows have this much momentum out to rela- the period July 1, 1994 – June 30, 1995. Astronomical tively large distances. Planetary nebulae do not, but with studies at the Department of Terrestrial Magnetism ~DTM! their characteristic high post-shock temperatures, collapse of the Carnegie Institution of Washington encompass again occurs. Hence all three outflows appear to be able to observational and theoretical fields of solar system and trigger the collapse of molecular clouds to form stars. planet formation and evolution, stars and star formation, Foster and Boss are continuing this work and examining galaxy kinematics and evolution, and various areas where the possibility of introducing 26Al into the early solar system these fields intersect. in a heterogeneous manner. Some meteoritical inclusions ~chondrules! show no evidence for live 26Al at the time of their formation. So either the chondrules formed after the 1. PERSONNEL aluminium had decayed away, or the solar nebula was not Staff Members: Sean C. Solomon ~Director!, Conel M. O’D. Alexander, Alan P. Boss, John A. Graham, Vera C. Rubin, uniformly populated with the isotope. Foster & Boss are ex- Franc¸ois Schweizer, George W. Wetherill ploring the injection of shock wave particles into the collaps- Postdoctoral Fellows: Harold M. Butner, John E. Chambers, ing solar system. Preliminary results are that ;40% of the Prudence N. Foster, Munir Humayun, Stacy S. McGaugh, incident shock particles are swallowed by the collapsing Bryan W. Miller, Elizabeth A. Myhill, David L. -
Galaxy Clusters: Waking Perseus
PUBLISHED: 2 JUNE 2017 | VOLUME: 1 | ARTICLE NUMBER: 164 news & views GALAXY CLUSTERS Waking Perseus The Perseus cluster contains over 1,000 a Kelvin–Helmholtz instability, which galaxies packed into a region ~3,500 kpc propagates in the wave direction and in extent. It is inevitable that such close- causes the dark area indicated in the packed galaxies will interact, and the image. This dark ‘bay-like’ feature is Chandra X-ray Observatory has observed approximately the size of the Milky Way, the beautiful result of that interaction and may be the result of a cold front in (pictured). This is no snapshot — the cluster gas: an interface where the Chandra observed the galaxy cluster temperature drops dramatically on scales for over 16 days in order to capture this much smaller than the mean free path. image. Stephen Walker and colleagues An advantage of this comparison of have retrieved the archival data and observations and simulations is that processed it to enhance the edges of (unmeasurable) physical quantities the surface brightness distribution. This can be estimated. In this case, the bay analysis, reported last year (Sanders et al., 50 kpc feature only appears in this form when Mon. Not. R. Astron. Soc. 460, 1898–1911; the ratio of the thermal pressure to the ROYAL ASTRONOMICAL SOCIETY ASTRONOMICAL ROYAL 2016), highlighted two features in the magnetic pressure is ~200, and this X-ray emission that are discussed by determination in turn allows the authors Walker et al. (Mon. Not. R. Astron. Soc. pattern seen in the image could have been to obtain an order-of-magnitude estimate 468, 2506–2516; 2017): the swirling wave generated by a passing galaxy cluster about of the magnetic field. -
A Spectroscopic Redshift Measurement for a Luminous Lyman Break Galaxy at Z = 7.730 Using Keck/Mosfire
Draft version May 5, 2015 Preprint typeset using LATEX style emulateapj v. 5/2/11 A SPECTROSCOPIC REDSHIFT MEASUREMENT FOR A LUMINOUS LYMAN BREAK GALAXY AT Z = 7:730 USING KECK/MOSFIRE P. A. Oesch1,2, P. G. van Dokkum2, G. D. Illingworth3, R. J. Bouwens4, I. Momcheva2, B. Holden3, G. W. Roberts-Borsani4,5, R. Smit6, M. Franx4, I. Labbe´4, V. Gonzalez´ 7, D. Magee3 Draft version May 5, 2015 ABSTRACT We present a spectroscopic redshift measurement of a very bright Lyman break galaxy at z = 7:7302 ± 0:0006 using Keck/MOSFIRE. The source was pre-selected photometrically in the EGS field as a robust z ∼ 8 candidate with H = 25:0 mag based on optical non-detections and a very red Spitzer/IRAC [3.6]−[4.5] broad-band color driven by high equivalent width [O III]+Hβ line emission. The Lyα line is reliably detected at 6:1σ and shows an asymmetric profile as expected for a galaxy embedded in a relatively neutral inter-galactic medium near the Planck peak of cosmic reionization. ˚ +90 The line has a rest-frame equivalent width of EW0 = 21 ± 4 A and is extended with VFWHM = 360−70 km s−1. The source is perhaps the brightest and most massive z ∼ 8 Lyman break galaxy in the 9:9±0:2 full CANDELS and BoRG/HIPPIES surveys, having assembled already 10 M of stars at only 650 Myr after the Big Bang. The spectroscopic redshift measurement sets a new redshift record for galaxies. This enables reliable constraints on the stellar mass, star-formation rate, formation epoch, as well as combined [O III]+Hβ line equivalent widths. -
The Large Scale Universe As a Quasi Quantum White Hole
International Astronomy and Astrophysics Research Journal 3(1): 22-42, 2021; Article no.IAARJ.66092 The Large Scale Universe as a Quasi Quantum White Hole U. V. S. Seshavatharam1*, Eugene Terry Tatum2 and S. Lakshminarayana3 1Honorary Faculty, I-SERVE, Survey no-42, Hitech city, Hyderabad-84,Telangana, India. 2760 Campbell Ln. Ste 106 #161, Bowling Green, KY, USA. 3Department of Nuclear Physics, Andhra University, Visakhapatnam-03, AP, India. Authors’ contributions This work was carried out in collaboration among all authors. Author UVSS designed the study, performed the statistical analysis, wrote the protocol, and wrote the first draft of the manuscript. Authors ETT and SL managed the analyses of the study. All authors read and approved the final manuscript. Article Information Editor(s): (1) Dr. David Garrison, University of Houston-Clear Lake, USA. (2) Professor. Hadia Hassan Selim, National Research Institute of Astronomy and Geophysics, Egypt. Reviewers: (1) Abhishek Kumar Singh, Magadh University, India. (2) Mohsen Lutephy, Azad Islamic university (IAU), Iran. (3) Sie Long Kek, Universiti Tun Hussein Onn Malaysia, Malaysia. (4) N.V.Krishna Prasad, GITAM University, India. (5) Maryam Roushan, University of Mazandaran, Iran. Complete Peer review History: http://www.sdiarticle4.com/review-history/66092 Received 17 January 2021 Original Research Article Accepted 23 March 2021 Published 01 April 2021 ABSTRACT We emphasize the point that, standard model of cosmology is basically a model of classical general relativity and it seems inevitable to have a revision with reference to quantum model of cosmology. Utmost important point to be noted is that, ‘Spin’ is a basic property of quantum mechanics and ‘rotation’ is a very common experience. -
An Extended Star Formation History in an Ultra-Compact Dwarf
MNRAS 451, 3615–3626 (2015) doi:10.1093/mnras/stv1221 An extended star formation history in an ultra-compact dwarf Mark A. Norris,1‹ Carlos G. Escudero,2,3,4 Favio R. Faifer,2,3,4 Sheila J. Kannappan,5 Juan Carlos Forte4,6 and Remco C. E. van den Bosch1 1Max Planck Institut fur¨ Astronomie, Konigstuhl¨ 17, D-69117 Heidelberg, Germany 2Facultad de Cs. Astronomicas´ y Geof´ısicas, UNLP, Paseo del Bosque S/N, 1900 La Plata, Argentina 3Instituto de Astrof´ısica de La Plata (CCT La Plata – CONICET – UNLP), Paseo del Bosque S/N, 1900 La Plata, Argentina 4Consejo Nacional de Investigaciones Cient´ıficas y Tecnicas,´ Rivadavia 1917, C1033AAJ Ciudad Autonoma´ de Buenos Aires, Argentina 5Department of Physics and Astronomy UNC-Chapel Hill, CB 3255, Phillips Hall, Chapel Hill, NC 27599-3255, USA 6Planetario Galileo Galilei, Secretar´ıa de Cultura, Ciudad Autonoma´ de Buenos Aires, Argentina Accepted 2015 May 29. Received 2015 May 28; in original form 2015 April 2 ABSTRACT Downloaded from There has been significant controversy over the mechanisms responsible for forming compact stellar systems like ultra-compact dwarfs (UCDs), with suggestions that UCDs are simply the high-mass extension of the globular cluster population, or alternatively, the liberated nuclei of galaxies tidally stripped by larger companions. Definitive examples of UCDs formed by either route have been difficult to find, with only a handful of persuasive examples of http://mnras.oxfordjournals.org/ stripped-nucleus-type UCDs being known. In this paper, we present very deep Gemini/GMOS spectroscopic observations of the suspected stripped-nucleus UCD NGC 4546-UCD1 taken in good seeing conditions (<0.7 arcsec). -
The Dynamical State of the Coma Cluster with XMM-Newton?
A&A 400, 811–821 (2003) Astronomy DOI: 10.1051/0004-6361:20021911 & c ESO 2003 Astrophysics The dynamical state of the Coma cluster with XMM-Newton? D. M. Neumann1,D.H.Lumb2,G.W.Pratt1, and U. G. Briel3 1 CEA/DSM/DAPNIA Saclay, Service d’Astrophysique, L’Orme des Merisiers, Bˆat. 709, 91191 Gif-sur-Yvette, France 2 Science Payloads Technology Division, Research and Science Support Dept., ESTEC, Postbus 299 Keplerlaan 1, 2200AG Noordwijk, The Netherlands 3 Max-Planck Institut f¨ur extraterrestrische Physik, Giessenbachstr., 85740 Garching, Germany Received 19 June 2002 / Accepted 13 December 2002 Abstract. We present in this paper a substructure and spectroimaging study of the Coma cluster of galaxies based on XMM- Newton data. XMM-Newton performed a mosaic of observations of Coma to ensure a large coverage of the cluster. We add the different pointings together and fit elliptical beta-models to the data. We subtract the cluster models from the data and look for residuals, which can be interpreted as substructure. We find several significant structures: the well-known subgroup connected to NGC 4839 in the South-West of the cluster, and another substructure located between NGC 4839 and the centre of the Coma cluster. Constructing a hardness ratio image, which can be used as a temperature map, we see that in front of this new structure the temperature is significantly increased (higher or equal 10 keV). We interpret this temperature enhancement as the result of heating as this structure falls onto the Coma cluster. We furthermore reconfirm the filament-like structure South-East of the cluster centre.