DOCSLIB.ORG

Departures from Axisymmetric Morphology and Dynamics in Spiral Galaxies

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Departures from Axisymmetric Morphology and Dynamics in Spiral Galaxies View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server Departures From Axisymmetric Morphology and Dynamics in Spiral Galaxies David A. Kornreich1 Center for Radiophysics and Space Research Cornell University Space Sciences Building, Ithaca NY 14853 [email protected] Martha P. Haynes Center for Radiophysics and Space Research and National Astronomy and Ionosphere Center2 Cornell University Space Sciences Building, Ithaca NY 14853 [email protected] R. V. E. Lovelace Cornell University Department of Astronomy Cornell University Space Sciences Building, Ithaca NY 14853 [email protected] and Liese van Zee3 National Radio Astronomy Observatory4 [email protected] ABSTRACT New H I synthesis data have been obtained for six face{on galaxies with the Very Large Array. These data and reanalyses of three additional data sets make up a sam- ple of nine face{on galaxies analyzed for deviations from axisymmetry in morphology and dynamics. This sample represents a subsample of galaxies already analyzed for morphological symmetry properties in the R-band. Four quantitative measures of dy- namical nonaxisymmetry are compared to one another and to the quantitative measures of morphological asymmetry in H I and R-band to investigate the relationships between nonaxisymmetric morphology and dynamics. We find no significant relationship between 1NASA Space Grant Graduate Fellow. 2The National Astronomy and Ionosphere Center is operated by Cornell University under a cooperative agreement with the National Science Foundation. 3Present Address: Herzberg Institute of Astrophysics, 5071 W. Saanich Rd, Victoria BC, V8X 4M6, Canada. 4The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under a cooperative agreement by Associated Universities, Inc. 1 asymmetric morphology and most of the dynamical measures in our sample. A possi- ble relationship is found, however, between morphology and dynamical position angle differences between approaching and receding sides of the galaxy. Subject headings: galaxies: kinematics and dynamics | galaxies: structure | methods: observational 2 1. Introduction non–axisymmetric morphology, and that many field spirals exhibit asymmetric dynamics, the question of Despite the fact that most studies of spiral galaxy whether the two phenomena are correlated, or even dynamics concentrate on understanding the proper- represent two pictures of a single underlying effect, ties of axisymmetric disks, evidence is accumulating remains open. that many galaxies lack such overall symmetry. Bald- Both optical morphology and gas dynamics pro- win et al. (1980) were first to seriously examine the vide clues as to the overall structure of a galaxy. For asymmetries in galactic disks, pointing out that lop- instance, Zaritsky & Rix (1997) proposed that op- sided galaxies were a common phenomenon not local- tical lopsidedness arises from tidal interactions, mi- ized to interacting pairs. nor mergers, or possibly gradual accretion. Conselice More recently, frequency of morphological asym- et al. (2000), on the other hand, find a correla- metry in galactic disks has been quantitatively stud- tion between optical asymmetry and B−V color, and ied at optical wavelengths. Based on optical mor- are able to use morphological asymmetry to identify phology, approximately 30% of disk galaxies exhibit whether starbursts in a given galaxy are likely caused significant “lopsidedness” (Rix & Zaritsky 1995; Ko- by interactions and mergers. Similarly, the neutral rnreich et al. 1998, hereafter KHL). These studies are hydrogen dynamics of asymmetric galaxies should be based on data sets containing some 30 targets each. able to distinguish between tidally deformed galaxies Dynamical asymmetry, too, has been examined in and those which are dynamically isolated. For in- large samples of single–dish H I line profiles. Richter stance, while the strongly optically–lopsided galaxy & Sancisi (1994), followed by the 104 galaxy sample of NGC 5474 is well–known to be under the tidal influ- Haynes et al. (1998, hereafter HHMRvZ), examined ence of its neighbor M101, the disturbed morpholo- the symmetry properties of single–dish H I line pro- gies of the other relatively isolated objects in the KHL files and determined that as many as ∼ 50% of spiral sample are not well–explained by standard tidal inter- galaxies show departures from the expected symmet- action models, which require particular dynamics as ric two–horned profile. Nevertheless, asymmetries in well as interactions with (unobserved) nearby com- line profiles are ambiguous evidence at best for dis- panions. turbed dynamics, since they combine both dynamic Alternatively, asymmetries may arise from the ex- and spatial information. citation of unstable, one–armed spiral modes possibly Until recently, however, little work had been done triggered by a past interaction or minor merger (Taga to examine the symmetry properties of neutral hy- & Iye 1998a, 1998b; Lovelace et al. 1999). Librations drogen in synthesis data. As a result, the connection of the optical galaxy about the minimum of the grav- between disturbed morphology and disturbed dynam- itational potential might also be set in motion by a ics in field disk galaxies is only now beginning to be previous interaction. As density is dependent on ra- seriously studied. Schoenmakers et al. (1997, here- dius in a galaxy, one might expect that the natural after SFdZ) outline a method for measuring small de- modes of a galaxy also depend on radius. The result- viations from axisymmetry of the potential of a filled ing differential oscillation might result in both lop- gas disk by breaking down the observed velocity field sided appearance and kinematic decoupling from the into its harmonic components. Recently, Swaters et optical light distribution. An understanding of these al. (1999, hereafter S3vA) have applied this method modes, if they exist, could provide a direct measure to the H I synthesis data of two galaxies, DDO 9 and of the dark matter distribution (Jog 1997; SFdZ). NGC 4395, where the hallmark of dynamical asymme- Another type of nonaxisymmetry, warping of galac- try is found to be asymmetry in the rotation curve, tic disks due to non-planar motions, has been pro- where one side of the curve rises more steeply than posed as an indicator of inclined flattened halo po- I the other. H synthesis observations of several other tentials (e.g. Dekel & Shlosman 1983; Toomre 1983), galaxies, e.g. NGC 3631 (Knapen 1997), NGC 5474 which are required to stabilize the warp against differ- (Rownd et al. 1994, hereafter RDH), and NGC 7217 ential precession, as well as observational indicators of (Buta et al. 1995), have also curiously revealed asym- massive dark halos (Tubbs & Sanders 1979). Warps metries or offsets between the optical centers of light may also be due to tidal interactions and accretion, and the kinematic centers of the neutral gas. While and have been reported to be related to non–circular much evidence exists that many field spirals exhibit motions, particularly m = 1 modes (Weinberg 1998). 3 Although “sloshing” librations in the plane of the UGC 6420, and NGC 4688 were selected for H I 21-cm galaxy would not imply a correlation between warps synthesis observations based on their apparent degree and lopsided dynamics, “flapping” librations normal of asymmetry and position in the sky such that they to the galactic plane could contribute to warping. could be observed at night during the time sched- In this paper, we present HI synthesis data for nine uled for the CS array. As the photometric analysis galaxies whose optical asymmetry properties were conducted in KHL had not yet been completed at quantified by KHL. Data obtained from the archives the time of the target selection, estimates of asym- at the Very Large Array (VLA)5 have been reana- metry were made by eye. Night–time observations lyzed for the galaxies NGC 5474, NGC 5701, and were preferred in order to minimize solar interference. UGC 12732, and new VLA data are presented for the The KHL sample was an optically selected sample of galaxies NGC 991, NGC 1024, UGC 3685, NGC 3596, disk galaxies chosen on the basis of face–on appear- UGC 6420, and NGC 4688. These galaxies represent ance to permit estimation of the optical morphological a sample of face–on galaxies selected on the basis of asymmetry unencumbered by factors such as absorp- their optical properties. tion by dust and inclination errors. The KHL selec- In §2, we discuss the acquisition and reduction of tion criteria were: small axial ratio, narrow (typically W < −1 the new and archived data for our sample of nine 50 ∼ 100 km s ) velocity width obtained from galaxies. In §3, we analyze the data obtained for devi- the private database of Giovanelli & Haynes known ations from morphological and dynamical axisymme- as the Arecibo General Catalog (AGC), and (except try and describe methods of determining the magni- for NGC 5474 and NGC 1042) isolation from obvious tudes of such deviations. These quantitative measures companions. See KHL for details of the optical target are useful for quantifying warps in face–on galaxies selection. and for non–circular motions in more inclined galax- H I observations of these targets were conducted in ies. We then use the sample to draw correlations be- August 1997, December 1998, and January 1999 with tween the symmetry parameters of the galaxies to one the VLA in its CS configuration. The CS configu- another and to global H I properties. Finally, in §4, ration is a modification of the C configuration which we present our conclusions in the context of other re- provides the resolution of the C array while main- cent work on galaxy asymmetry. taining a sufficient number of short spacings to pro- vide sampling of large–scale structure by positioning 2. Observations and Data Reduction one or more antennas at D configuration locations. In 1997, the CS configuration consisted of the stan- 2.1.
Load more

Recommended publications
  • CO Multi-Line Imaging of Nearby Galaxies (COMING) IV. Overview Of
    Publ. Astron. Soc. Japan (2018) 00(0), 1–33 1 doi: 10.1093/pasj/xxx000 CO Multi-line Imaging of Nearby Galaxies (COMING) IV. Overview of the Project Kazuo SORAI1, 2, 3, 4, 5, Nario KUNO4, 5, Kazuyuki MURAOKA6, Yusuke MIYAMOTO7, 8, Hiroyuki KANEKO7, Hiroyuki NAKANISHI9 , Naomasa NAKAI4, 5, 10, Kazuki YANAGITANI6 , Takahiro TANAKA4, Yuya SATO4, Dragan SALAK10, Michiko UMEI2 , Kana MOROKUMA-MATSUI7, 8, 11, 12, Naoko MATSUMOTO13, 14, Saeko UENO9, Hsi-An PAN15, Yuto NOMA10, Tsutomu, T. TAKEUCHI16 , Moe YODA16, Mayu KURODA6, Atsushi YASUDA4 , Yoshiyuki YAJIMA2 , Nagisa OI17, Shugo SHIBATA2, Masumichi SETA10, Yoshimasa WATANABE4, 5, 18, Shoichiro KITA4, Ryusei KOMATSUZAKI4 , Ayumi KAJIKAWA2, 3, Yu YASHIMA2, 3, Suchetha COORAY16 , Hiroyuki BAJI6 , Yoko SEGAWA2 , Takami TASHIRO2 , Miho TAKEDA6, Nozomi KISHIDA2 , Takuya HATAKEYAMA4 , Yuto TOMIYASU4 and Chey SAITA9 1Department of Physics, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan 2Department of Cosmosciences, Graduate School of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan 3Department of Physics, School of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan 4Division of Physics, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan 5Tomonaga Center for the History of the Universe (TCHoU), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan 6Department of Physical Science, Osaka Prefecture University, Gakuen 1-1,
    [Show full text]
  • The Radio Properties of a Complete Sample of Bright Galaxies
    Aust. J. Phys., 1982,35,321-50 The Radio Properties of a Complete Sample of Bright Galaxies J. I. Harnett School of Physics, University of Sydney, Sydney, N.S.W. 2006. Abstract Results are given for the radio continuum properties of an optically complete sample of 294 bright galaxies, 147 of which have been detected. Data were obtained with the 408 MHz Molonglo Radio Telescope. The radio luminosity functions for all galaxies and for spiral galaxies alone are derived and the radio emission for different galaxy types is investigated. Spectral indices of 73 galaxies which had been detected at other frequencies were derived; the mean index of a reliable subsample is <ex) = -0,71. 1. Introduction There have been many extensive surveys of continuum radio emission from bright galaxies. The earliest comprehensive survey of high sensitivity was that of Cameron (1971a, 1971b) using the Molonglo Cross Radio Telescope at 408 MHz. Cameron observed two optically complete samples south of b = + 18° and defined the radio luminosity function with reasonable statistics at radio powers of ~ 1022 W HZ-I. In the past decade the optical properties of galaxies have been revised so that the selection of an optically complete sample is more reliable. In addition, between 1970 and 1978 the sensitivity of the 408 MHz Molonglo Cross was improved by more than a magnitude, permitting more detections and more accurate measurements of weak' radio emission. Before observations at 408 MHz with the Molonglo Cross ceased in 1978, a new survey was made to improve Cameron's results and provide the best possible data base for subsequent investigations at different frequencies.
    [Show full text]
  • Breaking the Radio – Gamma-Ray Connection in Arp 220
    MNRAS 000, 000{000 (0000) Preprint 16 January 2019 Compiled using MNRAS LATEX style file v3.0 Breaking the Radio { Gamma-Ray Connection in Arp 220 Tova M. Yoast-Hull? and Norman Murrayy Canadian Institute for Theoretical Astrophysics, University of Toronto, ON, M5S 3H8, Canada 16 January 2019 ABSTRACT Recent analyses of the γ-ray spectrum from the ultra-luminous infrared galaxy Arp 220 have revealed a discrepancy in the cosmic ray energy injection rates derived from the γ-rays versus the radio emission. While the observed radio emission is consistent with the star formation rate inferred from infrared observations, a significantly higher cosmic ray population is necessary to accurately model the measured γ-ray flux. To resolve this discrepancy between the radio and γ-ray observations, we find that we must increase the cosmic ray energy injection rate and account for an infrared optical depth greater than unity. Raising the energy injection rate naturally raises the total γ-ray flux but also raises the radio flux unless there is also an increase in the energy loss rate for cosmic ray leptons. A optically thick medium results in an increase in energy losses via inverse Compton for cosmic ray leptons and preserves agreement with submillimeter, millimeter, and infrared wavelength observations. Key words: cosmic rays { galaxies: individual (Arp 220) { galaxies: starburst { gamma rays: galaxies { radiative transfer { radio continuum: galaxies 1 INTRODUCTION collide with the ISM to produce neutral pions that subse- quently decay into γ-rays. Over the past decade, eight star-forming galaxies (mostly gi- In our current understanding, the correlation between ant spirals) have been detected in γ-rays by Fermi, including radio and FIR emission seen in star-forming galaxies requires M31 (NGC 0224), NGC 0253, NGC 1068, NGC 2146, M82 two additional conditions to hold.
    [Show full text]
  • Structure and Star Formation in Disk Galaxies I. Sample Selection And
    Mon. Not. R. Astron. Soc. 000, 1–9 (2003) Printed 31 October 2018 (MN LATEX style file v1.4) Structure and star formation in disk galaxies I. Sample selection and near infrared imaging J. H. Knapen1,2, R. S. de Jong3, S. Stedman1 and D. M. Bramich4 1University of Hertfordshire, Department of Physical Sciences, Hatfield, Herts AL10 9AB 2Isaac Newton Group of Telescopes, Apartado 321, E-38700 Santa Cruz de La Palma, Spain 3Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 4School of Physics and Astronomy, University of St. Andrews, Scotland KY16 9SS Accepted March 2003. Received ; in original form ABSTRACT We present near-infrared imaging of a sample of 57 relatively large, Northern spiral galaxies with low inclination. After describing the selection criteria and some of the basic properties of the sample, we give a detailed description of the data collection and reduction procedures. The Ks λ =2.2µm images cover most of the disk for all galaxies, with a field of view of at least 4.2 arcmin. The spatial resolution is better than an arcsec for most images. We fit bulge and exponential disk components to radial profiles of the light distribution. We then derive the basic parameters of these components, as well as the bulge/disk ratio, and explore correlations of these parameters with several galaxy parameters. Key words: galaxies: spiral – galaxies: structure – infrared: galaxies 1 INTRODUCTION only now starting to be published (e.g., 2MASS: Skrutskie et al. 1997, Jarrett et al. 2003; Seigar & James 1998a, 1998b; Near-infrared (NIR) imaging of galaxies is a better tracer Moriondo et al.
    [Show full text]
  • The Applicability of Far-Infrared Fine-Structure Lines As Star Formation
    A&A 568, A62 (2014) Astronomy DOI: 10.1051/0004-6361/201322489 & c ESO 2014 Astrophysics The applicability of far-infrared fine-structure lines as star formation rate tracers over wide ranges of metallicities and galaxy types? Ilse De Looze1, Diane Cormier2, Vianney Lebouteiller3, Suzanne Madden3, Maarten Baes1, George J. Bendo4, Médéric Boquien5, Alessandro Boselli6, David L. Clements7, Luca Cortese8;9, Asantha Cooray10;11, Maud Galametz8, Frédéric Galliano3, Javier Graciá-Carpio12, Kate Isaak13, Oskar Ł. Karczewski14, Tara J. Parkin15, Eric W. Pellegrini16, Aurélie Rémy-Ruyer3, Luigi Spinoglio17, Matthew W. L. Smith18, and Eckhard Sturm12 1 Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, 9000 Gent, Belgium e-mail: [email protected] 2 Zentrum für Astronomie der Universität Heidelberg, Institut für Theoretische Astrophysik, Albert-Ueberle Str. 2, 69120 Heidelberg, Germany 3 Laboratoire AIM, CEA, Université Paris VII, IRFU/Service d0Astrophysique, Bat. 709, 91191 Gif-sur-Yvette, France 4 UK ALMA Regional Centre Node, Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK 5 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK 6 Laboratoire d0Astrophysique de Marseille − LAM, Université Aix-Marseille & CNRS, UMR7326, 38 rue F. Joliot-Curie, 13388 Marseille CEDEX 13, France 7 Astrophysics Group, Imperial College, Blackett Laboratory, Prince Consort Road, London SW7 2AZ, UK 8 European Southern Observatory, Karl
    [Show full text]
  • 1987Apj. . .320. .2383 the Astrophysical Journal, 320:238-257
    .2383 The Astrophysical Journal, 320:238-257,1987 September 1 © 1987. The American Astronomical Society. AU rights reserved. Printed in U.S.A. .320. 1987ApJ. THE IRÁS BRIGHT GALAXY SAMPLE. II. THE SAMPLE AND LUMINOSITY FUNCTION B. T. Soifer, 1 D. B. Sanders,1 B. F. Madore,1,2,3 G. Neugebauer,1 G. E. Danielson,4 J. H. Elias,1 Carol J. Lonsdale,5 and W. L. Rice5 Received 1986 December 1 ; accepted 1987 February 13 ABSTRACT A complete sample of 324 extragalactic objects with 60 /mi flux densities greater than 5.4 Jy has been select- ed from the IRAS catalogs. Only one of these objects can be classified morphologically as a Seyfert nucleus; the others are all galaxies. The median distance of the galaxies in the sample is ~ 30 Mpc, and the median 10 luminosity vLv(60 /mi) is ~2 x 10 L0. This infrared selected sample is much more “infrared active” than optically selected galaxy samples. 8 12 The range in far-infrared luminosities of the galaxies in the sample is 10 LQ-2 x 10 L©. The far-infrared luminosities of the sample galaxies appear to be independent of the optical luminosities, suggesting a separate luminosity component. As previously found, a correlation exists between 60 /¿m/100 /¿m flux density ratio and far-infrared luminosity. The mass of interstellar dust required to produce the far-infrared radiation corre- 8 10 sponds to a mass of gas of 10 -10 M0 for normal gas to dust ratios. This is comparable to the mass of the interstellar medium in most galaxies.
    [Show full text]
  • 194 9 Ce Le B Rating 65 Ye Ars O F Br Inging As Tr on Omy T O No Rth Te X As 2
    1949 Celebrating 65 Years of Bringing Astronomy to North Texas 2014 Contact information: Inside this issue: Info Officer (General Info) – [email protected] Website Administrator – [email protected] Page Postal Address: November Club Calendar 3 Fort Worth Astronomical Society Celestial Events 4 c/o Matt McCullar 5801 Trail Lake Drive Sky Chart 5 Fort Worth, TX 76133 Moon Phase Calendar 6 Web Site: http://www.fortworthastro.org Facebook: http://tinyurl.com/3eutb22 Lunar Occultations/Conjs 7 Twitter: http://twitter.com/ftwastro Yahoo! eGroup (members only): http://tinyurl.com/7qu5vkn Mercury/Venus Chart 8 Officers (2014-2015): Mars/Minor Planets Charts 9 President – Bruce Cowles, [email protected] Jupiter Charts 10 Vice President – Russ Boatwright, [email protected] Sec/Tres – Michelle Theisen, [email protected] Planet Vis & ISS Passes 11 Board Members: CSAC Event Update 12 2014-2016 Mike Langohr Young Astronomer News 12 Tree Oppermann ‘66 Leonids Remembered 13 2013-2015 Bill Nichols Cloudy Night Library 15 Jim Craft Cover Photo: Monthly AL Observing Club 17 Composite image taken by FWAS mem- bers: Left to right, from top to bottom— Constellation of the Month 18 Laura Cowles, Mike Ahner, Brian Wortham, Constellation Mythology 19 Shawn Kirchdorfer, Mark Wainright, Phil Stage, Patrick McMahon, Dennis Webb, Ben Prior Club Meeting Minutes 20 Hudgens, Shawn Kirchdorfer, John McCrea, and Chris Mlodnicki General Club Information 21 That’s A Fact 21 Observing Site Reminders: Be careful with fire, mind all local burn bans! Full Moon Name 21 Dark Site Usage Requirements (ALL MEMBERS): FWAS Foto Files 22 Maintain Dark-Sky Etiquette (http://tinyurl.com/75hjajy) Turn out your headlights at the gate! Sign the logbook (in camo-painted storage shed.
    [Show full text]
  • The Large Scale Distribution of Radio Continuum in Ε and So Galaxies
    THE LARGE SCALE DISTRIBUTION OF RADIO CONTINUUM IN Ε AND SO GALAXIES R.D. Ekers, Kapteyn Astronomical Institute, University of Groningen If we look at the radio properties of the nearby ellipticals we find a situation considerably different from that just described by van der Kruit for the spiral galaxies. For example NGC 5128 (Cen A), the nearest giant elliptical galaxy, is a thousand times more powerful a radio source than the brightest spiral galaxies and furthermore its radio emission comes from a multiple lobed radio structure which bears no resemblance to the optical light distribution (e.g. Ekers, 1975). The other radio emitting elliptical galaxies in our neighbourhood, NGC 1316 (Fornax A), IC 4296 (1333-33), have similar morphology. A question which then arises is whether at lower levels we can detect radio emission coming from the optical image of the elliptical galaxies and which may be more closely related to the kind of emission seen in the spiral galaxies. Since elliptical galaxies are less numerous than spiral galaxies we have to search out to the Virgo cluster to obtain a good sample. Some results from a Westerbork map of the central region of the Virgo cluster at 1.4 GHz (Kotanyi and Ekers, in preparation) is given in the Table. Radio Emission from Galaxies in the core of the Virgo Cluster Name Hubble m Flux density NGC Type Ρ (JO"29 W m-2 Hz-1) 4374 El 10.8 6200 3C 272.1 4388 Sc 12.2 140 4402 Sd 13.6 60 4406 E3 10.9 < 4 4425 SO 13.3 < 4 4435 SO 1 1.9 < 5 4438 S pec 12.0 150 This result is typical for spiral and elliptical galaxies and illustrates the different properties quite well.
    [Show full text]
  • Evidence for Connecting Them to Boxy/Peanut Bulges M
    A&A 599, A43 (2017) Astronomy DOI: 10.1051/0004-6361/201628849 & c ESO 2017 Astrophysics Colors of barlenses: evidence for connecting them to boxy/peanut bulges M. Herrera-Endoqui1, H. Salo1, E. Laurikainen1, and J. H. Knapen2; 3 1 Astronomy Research Unit, University of Oulu, 90014 Oulu, Finland e-mail: [email protected] 2 Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain 3 Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain Received 3 May 2016 / Accepted 7 September 2016 ABSTRACT Aims. We aim to study the colors and orientations of structures in low and intermediate inclination barred galaxies. We test the hy- pothesis that barlenses, roundish central components embedded in bars, could form part of the bar in a similar manner to boxy/peanut bulges in the edge-on view. Methods. A sample of 79 barlens galaxies was selected from the Spitzer Survey of Stellar Structure in Galaxies (S4G) and the Near IR S0 galaxy Survey (NIRS0S), based on previous morphological classifications at 3.6 µm and 2.2 µm wavelengths. For these galaxies the sizes, ellipticities, and orientations of barlenses were measured, parameters which were used to define the barlens regions in the color measurements. In particular, the orientations of barlenses were studied with respect to those of the “thin bars” and the line-of- nodes of the disks. For a subsample of 47 galaxies color index maps were constructed using the Sloan Digital Sky Survey (SDSS) images in five optical bands, u, g, r, i, and z. Colors of bars, barlenses, disks, and central regions of the galaxies were measured using two different approaches and color−color diagrams sensitive to metallicity, stellar surface gravity, and short lived stars were constructed.
    [Show full text]
  • Detection of Multiple Stellar Streams in the Environment of NGC 1052 Oliver Müller1, R
    Astronomy & Astrophysics manuscript no. new c ESO 2021 September 18, 2021 Letter to the Editor A tidal’s tale: detection of multiple stellar streams in the environment of NGC 1052 Oliver Müller1, R. Michael Rich2, Javier Román34, Mustafa K. Yıldız156, Michal Bílek1, Pierre-Alain Duc1, Jérémy Fensch7, Ignacio Trujillo34, and Andreas Koch8 1 Université de Strasbourg, Observatoire Astronomique de Strasbourg (ObAS), CNRS UMR 7550 Strasbourg, France e-mail: [email protected] 2 Dept. of Physics and Astronomy, UCLA, Los Angeles, CA 90095-1547 3 Instituto de Astrofísica de Canarias (IAC), La Laguna, 38205, Spain 4 Departamento de Astrofísica, Universidad de La Laguna (ULL), E-38200, La Laguna, Spain 5 Astronomy and Space Sciences Department, Science Faculty, Erciyes University, Kayseri, 38039 Turkey 6 Erciyes University, Astronomy and Space Sciences Observatory Applied and Research Center (UZAYBIMER),˙ 38039, Kayseri, Turkey 7 European Southern Observatory, Karl-Schwarzschild Strasse 2, 85748, Garching, Germany 8 Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12–14, 69120 Heidelberg, Germany Received tba; accepted tba ABSTRACT The possible existence of two dark matter free galaxies (NGC1052-DF2 and NGC1052-DF4) in the field of the early-type galaxy NGC 1052 faces a challenge to current theories of dwarf galaxy formation according to the current cosmological paradigm. We carried out a search for signatures of past interactions connected to the putative hosts of NGC 1052-DF2 and NGC 1052-DF4 using a very deep image obtained with the 0.7 m Jeanne Rich telescope that reach a surface brightness limit of ∼29 mag arcsec−2 in the r band.
    [Show full text]
  • 190 Index of Names
    Index of names Ancora Leonis 389 NGC 3664, Arp 005 Andriscus Centauri 879 IC 3290 Anemodes Ceti 85 NGC 0864 Name CMG Identification Angelica Canum Venaticorum 659 NGC 5377 Accola Leonis 367 NGC 3489 Angulatus Ursae Majoris 247 NGC 2654 Acer Leonis 411 NGC 3832 Angulosus Virginis 450 NGC 4123, Mrk 1466 Acritobrachius Camelopardalis 833 IC 0356, Arp 213 Angusticlavia Ceti 102 NGC 1032 Actenista Apodis 891 IC 4633 Anomalus Piscis 804 NGC 7603, Arp 092, Mrk 0530 Actuosus Arietis 95 NGC 0972 Ansatus Antliae 303 NGC 3084 Aculeatus Canum Venaticorum 460 NGC 4183 Antarctica Mensae 865 IC 2051 Aculeus Piscium 9 NGC 0100 Antenna Australis Corvi 437 NGC 4039, Caldwell 61, Antennae, Arp 244 Acutifolium Canum Venaticorum 650 NGC 5297 Antenna Borealis Corvi 436 NGC 4038, Caldwell 60, Antennae, Arp 244 Adelus Ursae Majoris 668 NGC 5473 Anthemodes Cassiopeiae 34 NGC 0278 Adversus Comae Berenices 484 NGC 4298 Anticampe Centauri 550 NGC 4622 Aeluropus Lyncis 231 NGC 2445, Arp 143 Antirrhopus Virginis 532 NGC 4550 Aeola Canum Venaticorum 469 NGC 4220 Anulifera Carinae 226 NGC 2381 Aequanimus Draconis 705 NGC 5905 Anulus Grahamianus Volantis 955 ESO 034-IG011, AM0644-741, Graham's Ring Aequilibrata Eridani 122 NGC 1172 Aphenges Virginis 654 NGC 5334, IC 4338 Affinis Canum Venaticorum 449 NGC 4111 Apostrophus Fornac 159 NGC 1406 Agiton Aquarii 812 NGC 7721 Aquilops Gruis 911 IC 5267 Aglaea Comae Berenices 489 NGC 4314 Araneosus Camelopardalis 223 NGC 2336 Agrius Virginis 975 MCG -01-30-033, Arp 248, Wild's Triplet Aratrum Leonis 323 NGC 3239, Arp 263 Ahenea
    [Show full text]
  • Making a Sky Atlas
    Appendix A Making a Sky Atlas Although a number of very advanced sky atlases are now available in print, none is likely to be ideal for any given task. Published atlases will probably have too few or too many guide stars, too few or too many deep-sky objects plotted in them, wrong- size charts, etc. I found that with MegaStar I could design and make, specifically for my survey, a “just right” personalized atlas. My atlas consists of 108 charts, each about twenty square degrees in size, with guide stars down to magnitude 8.9. I used only the northernmost 78 charts, since I observed the sky only down to –35°. On the charts I plotted only the objects I wanted to observe. In addition I made enlargements of small, overcrowded areas (“quad charts”) as well as separate large-scale charts for the Virgo Galaxy Cluster, the latter with guide stars down to magnitude 11.4. I put the charts in plastic sheet protectors in a three-ring binder, taking them out and plac- ing them on my telescope mount’s clipboard as needed. To find an object I would use the 35 mm finder (except in the Virgo Cluster, where I used the 60 mm as the finder) to point the ensemble of telescopes at the indicated spot among the guide stars. If the object was not seen in the 35 mm, as it usually was not, I would then look in the larger telescopes. If the object was not immediately visible even in the primary telescope – a not uncommon occur- rence due to inexact initial pointing – I would then scan around for it.
    [Show full text]