DOCSLIB.ORG

Chemical Abundances in Virgo Spiral Galaxies II: Effects of Cluster

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Chemical Abundances in Virgo Spiral Galaxies II: Effects of Cluster CHEMICAL ABUNDANCES IN VIRGO SPIRAL GALAXIES I I EFFECTS OF CLUSTER ENVIRONMENT Evan D Skillman Astronomy Department University of Minnesota Church St S E Minneap olis MN skillmanzonspaumnedu Rob ert C Kennicutt Jr Steward Observatory University of Arizona Tucson AZ robkasarizonaedu Gregory A Shields Astronomy Department University of Texas Austin TX shieldsastroasutexasedu and Dennis Zaritsky UCOLick Observatory and Board of Astronomy and Astrophysics astro-ph/9511019 03 Nov 95 University of California Santa Cruz CA dennislickucscedu Received accepted Based on observations obtained at the Multiple Mirror Telescope a joint facility of the University of Arizona and the Smithsonian Institution ABSTRACT We present new measurements of chemical abundances in H II regions in spiral galaxies of the Virgo cluster and a comparison of Virgo galaxies and eld spirals With these new data there now exist nine Virgo spirals with abundance measurements for at least four H II regions Our sample of Virgo galaxies ranges from H I decient ob jects near the core of the cluster to galaxies with normal H I prop erties far from the cluster core We investigate the relationship b etween H I disk characteristics and chemical abundances to determine whether dynamical pro cesses that remove gas from the disk such as ram pressure stripping by the intracluster medium also aect the chemical abundances We divide the nine Virgo spirals into three groups of three galaxies each those with strong H I deciencies intermediate cases and those with no H I deciencies The three most H I decient Virgo spirals have larger mean abundances to dex in OH than the spirals on the p eriphery of the cluster This suggests that dynamical pro cesses asso ciated with the cluster environment are more imp ortant than cluster membership in determining the current chemical prop erties of spiral galaxies There is also weak evidence of shallower abundance gradients in the H I decient Virgo spirals We also compare the abundance prop erties of our Virgo sample to a large sample of eld spirals studied by Zaritsky Kennicutt Huchra Those authors found that the mean abundance of the disk gas increases with increasing maximum circular velocity increasing luminosity and decreasing earlier Hubble type but with a large disp ersion in the mean abundances and abundance gradients The disp ersion in the prop erties of eld galaxies and the small size of the Virgo sample make it dicult to draw denitive conclusions ab out any systematic dierence b etween the eld and Virgo spirals Nevertheless the H I decient Virgo galaxies have larger mean abundances than eld galaxies of comparable luminosity or Hubble type while the spirals at the p eriphery of the cluster are indistinguisha ble from the eld galaxies Simple illustrative chemical evolution mo dels with infall of metalp o or gas are constructed and compared to mo dels in which the infall is terminated The mo dels are constrained by comparison with observed gas mass fractions current star formation rates and gas consumption times The mo del results indicate that the curtailment of infall of metalp o or gas onto cluster core spirals may explain part of the enhanced abundance However additional work is needed particularly mo deling of the eects of truncating the outer gaseous disk within the context of mo dels with radial gas transp ort The increased abundances in cluster core latetype spirals relative to eld galaxies may b e imp ortant in the interpretation of observations of these galaxies Sp ecically we p oint to p ossible eects on the TullyFisher and Cepheid variable distance determinations and the interpretation of colors in the ButcherOemler eect Subject headings galaxies abundances galaxies clustering galaxies evolution galaxies interstellar medium galaxies intergalactic medium galaxies structure galaxies distances nebulae H II regions INTRODUCTION Spiral galaxies are mo died by the environment within a rich cluster of galaxies see reviews by Haynes and Whitmore and the introduction to Henry et al Such eects as tidal stripping ram pressure stripping and ablation by the intracluster medium must aect galaxy evolution The cluster environment clearly inuences galaxy morphology Dressler Postman Geller and so a natural question is whether it also aects the star formation history and chemical evolution of galaxies Do es the cluster environment predetermine galaxy morphology by solely inuencing initial conditions or do es it continually inuence the evolution of a member galaxy Comparing the chemical abundances of eld and cluster members may provide clues to these fundamental questions Moreover a systematic abundance dierential b etween cluster and eld galaxies would have implications for the stellar p opulations and could impact a number of currently p opular distance indicators The Virgo cluster due to its proximity provides the logical starting p oint for the study of environmental eects on abundances in cluster spirals The Virgo cluster is irregular and in some resp ects this compromises the study of environmental eects However the extensive catalog of the p ositions morphologies and radial velocities of galaxies by Binggeli Sandage Tammann allows a denition of the clusters structure In addition the structure of the hot gas comp onent which has b een revealed through sensitive mapping of the Xray emission made p ossible by ROSAT Boringer et al is very similar to the galaxy distribution Substantial evidence p oints to dierences b etween the spiral galaxies in the core of the Virgo cluster and eld spiral galaxies Davies Lewis rst p ointed to a deciency in H I gas in Virgo spirals when compared to eld spirals Giovanelli Haynes showed that galaxies in the outer parts of the Virgo cluster and eight other clusters were less decient in H I than the galaxies in the core of the cluster From H I synthesis observations of Virgo cluster spirals Warmels concluded the H I deciencies could b e attributed to a depletion of the H I at large galacto centric radii This was supp orted by Cayatte et al CKBG Because the star formation history of a galaxy is related to its gas content it is logical to ask if the chemical abundances in the cluster spirals are dierent from those of eld galaxies Shields Skillman Kennicutt SSK presented sp ectrophotometry of H II regions in ve Virgo spirals The Virgo spirals app eared to b e considerably more metal rich dex than the typical galaxy in their eld sample SSK suggested that such a dierence could result from dierences in infall or radial inow rates Henry et al HPLC and Henry Pagel Chincarini HPC conducted intensive studies of two Virgo spirals and found the evidence of a Virgoeld dierential less convincing Hence the issue of chemical abundance anomalies in the Virgo cluster is unresolved The existing data sets have b een to o small to address the most fundamental physical question whether the chemical prop erties of the H I decient galaxies in the core of the Virgo cluster are dierent from those of undisturb ed galaxies in Virgo or elsewhere We have undertaken a larger investigation which is aimed at addressing these problems in four ways by enlarging the Virgo sample choosing galaxies within Virgo that span the range of observed H I prop erties using published data on the H I distributions within galaxies to examine the relationship b etween the H I distribution and chemical abundance and by comparing the prop erties of the Virgo galaxies to a much larger sample of eld spirals than was previously available This study includes measurements of more H II regions in the strongly H I decient galaxies NGC and NGC for which SSK had only one H II region each and in several spirals with mo derate or no H I deciency Our work increases the number of Virgo spirals with abundance measurements of four or more H II regions to nine For a comparison eld sample we use the data for eld spirals recently published by Zaritsky Kennicutt Huchra ZKH In this pap er we describ e the observations and discuss the implications for the questions raised ab ove In Section we discuss the sample selection new observations data reduction pro cedures and OH abundance determinations In Section we discuss the abundance prop erties of the Virgo spirals test for any dep endence of abundance prop erties on cluster lo cation or H I deciency and use the ZKH results to determine whether there are any systematic dierences b etween the eld and cluster galaxies In Section we characterize and quantify the abundance dierential seen for the H I decient spiral galaxies In Section we assess these results in the context of a simple mo del for environmental eects on chemical evolution and in Section we outline future observational pro jects and discuss the implications of elevated abundances for other studies of cluster spirals OBSERVATIONS Galaxy Selection The primary ob jective of this program is to measure H II region abundances for a large number of Virgo cluster spirals that span a larger range of H I deciency Following SSK we chose to restrict our sample to latetype spirals those classied as type Sb c or later in the Revised ShapleyAmes Catalog RSA Sandage Tammann This was done to limit the variation in abundances due to variations in galaxy type Oey Kennicutt OK ZKH and to take advantage of the brighter H II regions in latetype galaxies We compiled a list of spirals in this type range that were mapp ed in H I by Warmels or Cayatte et al We then selected a subset of galaxies exhibiting the full
Load more

Recommended publications
  • A Multivariate Statistical Analysis of Spiral Galaxy Luminosities. I. Data and Results
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server A Multivariate Statistical Analysis of Spiral Galaxy Luminosities. I. Data and Results Alice Shapley California Institute of Technology, Pasadena CA, 91125, USA G. Fabbiano Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 P. B. Eskridge Ohio State University, Dept. of Astronomy, 140 W 18th Ave, Columbus, OH 43210 ABSTRACT We have performed a multiparametric analysis of luminosity data for a sample of 234 normal spiral and irregular galaxies observed in X-rays with the Einstein Observatory. This sample is representative of S and Irr galaxies, with a good coverage of morphological types and absolute magnitudes. In addition to X-ray and optical data, we have compiled H-band magnitudes, IRAS near- and far-infrared, and 6cm radio continuum observations for the sample from the literature. We have also performed a careful compilation of distance estimates. We have explored the effect of morphology by dividing the sample into early (S0/a-Sab), intermediate (Sb-Sbc), and late-type (Sc-Irr) subsamples. The data were analysed with bivariate and multivariate survival analysis techniques that make full use of all the information available in both detections and limits. We find that most pairs of luminosities are correlated when considered individually, and this is not due to a distance bias. Different luminosity-luminosity correlations follow different power-law relations. Contrary to previous reports, the LX LB correlation follows a power-law with exponent − larger than 1. Both the significances of some correlations and their power-law relations are morphology dependent.
    [Show full text]
  • Download This Article in PDF Format
    A&A 598, A114 (2017) Astronomy DOI: 10.1051/0004-6361/201629213 & c ESO 2017 Astrophysics Bars as seen by Herschel and Sloan Guido Consolandi1, Massimo Dotti1, Alessandro Boselli2, Giuseppe Gavazzi1, and Fabio Gargiulo1 1 Dipartimento di Fisica G. Occhialini, Università di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy e-mail: [email protected] 2 Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille), UMR 7326, 13388 Marseille, France Received 30 June 2016 / Accepted 30 December 2016 ABSTRACT We present an observational study of the effect of bars on the gas component and on the star formation properties of their host galaxies in a statistically significant sample of resolved objects, the Herschel Reference Sample. The analysis of optical and far-infrared images allows us to identify a clear spatial correlation between stellar bars and the cold-gas distribution mapped by the warm dust emission. We find that the infrared counterparts of optically identified bars are either bar-like structures or dead central regions in which star formation is strongly suppressed. Similar morphologies are found in the distribution of star formation directly traced by Hα maps. The sizes of such optical and infrared structures correlate remarkably well, hinting at a causal connection. In the light of previous observations and of theoretical investigations in the literature, we interpret our findings as further evidence of the scenario in which bars drive strong inflows toward their host nuclei: young bars are still in the process of perturbing the gas and star formation clearly delineates the shape of the bars; old bars on the contrary already removed any gas within their extents, carving a dead region of negligible star formation.
    [Show full text]
  • Stellar Tidal Streams As Cosmological Diagnostics: Comparing Data and Simulations at Low Galactic Scales
    RUPRECHT-KARLS-UNIVERSITÄT HEIDELBERG DOCTORAL THESIS Stellar Tidal Streams as Cosmological Diagnostics: Comparing data and simulations at low galactic scales Author: Referees: Gustavo MORALES Prof. Dr. Eva K. GREBEL Prof. Dr. Volker SPRINGEL Astronomisches Rechen-Institut Heidelberg Graduate School of Fundamental Physics Department of Physics and Astronomy 14th May, 2018 ii DISSERTATION submitted to the Combined Faculties of the Natural Sciences and Mathematics of the Ruperto-Carola-University of Heidelberg, Germany for the degree of DOCTOR OF NATURAL SCIENCES Put forward by GUSTAVO MORALES born in Copiapo ORAL EXAMINATION ON JULY 26, 2018 iii Stellar Tidal Streams as Cosmological Diagnostics: Comparing data and simulations at low galactic scales Referees: Prof. Dr. Eva K. GREBEL Prof. Dr. Volker SPRINGEL iv NOTE: Some parts of the written contents of this thesis have been adapted from a paper submitted as a co-authored scientific publication to the Astronomy & Astrophysics Journal: Morales et al. (2018). v NOTE: Some parts of this thesis have been adapted from a paper accepted for publi- cation in the Astronomy & Astrophysics Journal: Morales, G. et al. (2018). “Systematic search for tidal features around nearby galaxies: I. Enhanced SDSS imaging of the Local Volume". arXiv:1804.03330. DOI: 10.1051/0004-6361/201732271 vii Abstract In hierarchical models of galaxy formation, stellar tidal streams are expected around most galaxies. Although these features may provide useful diagnostics of the LCDM model, their observational properties remain poorly constrained. Statistical analysis of the counts and properties of such features is of interest for a direct comparison against results from numeri- cal simulations. In this work, we aim to study systematically the frequency of occurrence and other observational properties of tidal features around nearby galaxies.
    [Show full text]
  • Structure, Properties and Formation Histories of S0 Galaxies
    Structure, Properties and Formation Histories of S0 Galaxies by Kaustubh Vaghmare Thesis Supervisor Prof. Ajit K. Kembhavi A thesis presented for the degree of Doctor of Philosophy to IUCAA & Jawaharlal Nehru University India July, 2015 Structure, Properties and Formation Histories of S0 Galaxies by Kaustubh Vaghmare c 2015 All rights reserved. Certificate This is to certify that the thesis entitled Structure, Properties and Formation Histories of S0 Galaxies submitted by Mr. Kaustubh Vaghmare for the award of the degree of Doctor of Philosophy to Jawaharlal Nehru University, New Delhi is his original work. This has not been published or submitted to any other University for any other Degree or Diploma. Pune July 30th, 2015 Prof. Ajit K. Kembhavi (Thesis Advisor & Director, IUCAA) Declaration I hereby declare that the work reported in this thesis is entirely original. This thesis is composed independently by me at the Inter-University Centre for Astronomy and Astrophysics, Pune under the supervision of Prof. Ajit K. Kembhavi. I further declare that the subject matter presented in the thesis has not previously formed the basis for the award of any degree, diploma, associateship, fellowship or any other similar title of any University or Institution. Pune July 30th, 2015 Prof. Ajit K. Kembhavi Mr. Kaustubh Vaghmare (Thesis Advisor) (Ph.D. Candidate) 3 Dedicated to ... Prathama & Prakash (my parents, my Gods) Rahul (my brother, whose ever presence with my parents and unquestioning support allowed me to work in peace) & Sneha (my beloved) 5 Acknowledgements For all students and regular visitors, it is clear that Prof. Ajit Kembhavi is one of the busiest people with frequent meetings, visits abroad, directorial duties and several other responsibilities.
    [Show full text]
  • And Ecclesiastical Cosmology
    GSJ: VOLUME 6, ISSUE 3, MARCH 2018 101 GSJ: Volume 6, Issue 3, March 2018, Online: ISSN 2320-9186 www.globalscientificjournal.com DEMOLITION HUBBLE'S LAW, BIG BANG THE BASIS OF "MODERN" AND ECCLESIASTICAL COSMOLOGY Author: Weitter Duckss (Slavko Sedic) Zadar Croatia Pусскй Croatian „If two objects are represented by ball bearings and space-time by the stretching of a rubber sheet, the Doppler effect is caused by the rolling of ball bearings over the rubber sheet in order to achieve a particular motion. A cosmological red shift occurs when ball bearings get stuck on the sheet, which is stretched.“ Wikipedia OK, let's check that on our local group of galaxies (the table from my article „Where did the blue spectral shift inside the universe come from?“) galaxies, local groups Redshift km/s Blueshift km/s Sextans B (4.44 ± 0.23 Mly) 300 ± 0 Sextans A 324 ± 2 NGC 3109 403 ± 1 Tucana Dwarf 130 ± ? Leo I 285 ± 2 NGC 6822 -57 ± 2 Andromeda Galaxy -301 ± 1 Leo II (about 690,000 ly) 79 ± 1 Phoenix Dwarf 60 ± 30 SagDIG -79 ± 1 Aquarius Dwarf -141 ± 2 Wolf–Lundmark–Melotte -122 ± 2 Pisces Dwarf -287 ± 0 Antlia Dwarf 362 ± 0 Leo A 0.000067 (z) Pegasus Dwarf Spheroidal -354 ± 3 IC 10 -348 ± 1 NGC 185 -202 ± 3 Canes Venatici I ~ 31 GSJ© 2018 www.globalscientificjournal.com GSJ: VOLUME 6, ISSUE 3, MARCH 2018 102 Andromeda III -351 ± 9 Andromeda II -188 ± 3 Triangulum Galaxy -179 ± 3 Messier 110 -241 ± 3 NGC 147 (2.53 ± 0.11 Mly) -193 ± 3 Small Magellanic Cloud 0.000527 Large Magellanic Cloud - - M32 -200 ± 6 NGC 205 -241 ± 3 IC 1613 -234 ± 1 Carina Dwarf 230 ± 60 Sextans Dwarf 224 ± 2 Ursa Minor Dwarf (200 ± 30 kly) -247 ± 1 Draco Dwarf -292 ± 21 Cassiopeia Dwarf -307 ± 2 Ursa Major II Dwarf - 116 Leo IV 130 Leo V ( 585 kly) 173 Leo T -60 Bootes II -120 Pegasus Dwarf -183 ± 0 Sculptor Dwarf 110 ± 1 Etc.
    [Show full text]
  • CFAS Astropicture of the Month
    1 NGC 4651: The Umbrella Galaxy is a mere 62 million light-years distant, toward the well-groomed northern constellation Coma Berenices. About the size of our Milky Way, this island universe is seen to have a faint umbrella-shaped structure that seems to extend (left) some 100 thousand light-years beyond the bright galactic disk. The giant cosmic umbrella is now known to be composed of tidal star streams - extensive trails of stars gravitationally stripped from a smaller satellite galaxy. The small galaxy was eventually torn apart in repeated encounters as it swept back and forth on eccentric orbits through NGC 4651. In fact, the picture insert zooms in on the smaller galaxy's remnant core, identified in an extensive exploration of the system, using data from the large Subaru and Keck telescopes on Mauna Kea. Work begun by a remarkable collaboration of amateur and professional astronomers to image faint structures around bright galaxies suggests that even in nearby galaxies, tidal star streams are common markers of such galactic mergers. The result is explained by models of galaxy formation that also apply to our own Milky Way.4651 2 Spiral galaxy NGC 4651 is a mere 35 million light-years distant, toward the well- groomed constellation Coma Berenices. About 50 thousand light-years across, this galaxy is seen to have a faint umbrella-shaped structure (right) that seems to extend some 50 thousand light-years farther, beyond the bright galactic disk. The giant cosmic umbrella is now known to be composed of tidal star streams. The streams themselves are extensive trails of stars gravitationally stripped from a smaller satellite galaxy that was eventually torn apart.
    [Show full text]
  • Classification of Galaxies Using Fractal Dimensions
    UNLV Retrospective Theses & Dissertations 1-1-1999 Classification of galaxies using fractal dimensions Sandip G Thanki University of Nevada, Las Vegas Follow this and additional works at: https://digitalscholarship.unlv.edu/rtds Repository Citation Thanki, Sandip G, "Classification of galaxies using fractal dimensions" (1999). UNLV Retrospective Theses & Dissertations. 1050. http://dx.doi.org/10.25669/8msa-x9b8 This Thesis is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Thesis has been accepted for inclusion in UNLV Retrospective Theses & Dissertations by an authorized administrator of Digital Scholarship@UNLV. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted.
    [Show full text]
  • RA Dec Max @ @ Rise Tran Sets 2000.0 2000.0 Alt° Time Azm
    RA Dec Max @ @ Rise Tran Sets Size M# Seq Type Cons mv Remarks Observed / Details 2000.0 2000.0 Alt° time Azm° @ @ @ (arcmin) A large, face-on, faint, illusive spiral. One of the most difficult of the Messier objects especially in M74 1 G-SAc Psc 1 hr 37m 15° 47' 29.12 18:09 255.94 xx:xx xx:xx 21:27 10.2 10.2x9.5 small telescopes and for northern marathoners due to its low altitude at sunset in March. A bright, compact Seyfert galaxy with a star-like nucleus - use high power. The closest Messier to the ecliptic (next is M78). Tough for northern M77 2 G-SABab Cet 2 hr 43m 0° 1' 24.2 18:09 231.09 xx:xx xx:xx 21:01 8.9 7x6 marathoners due to its low altitude at sunset in March. (There is a 64.3 minute RA gap between M77 and M45.) A large diffuse spiral - requires a dark sky. This face- on spiral can be difficult to see due to it's large size. M33 3 G-SAcd Tri 1 hr 34m 30° 39' 40.27 18:09 267.98 04:15 xx:xx 23:28 6.7 73x45 Use low power (may be easier to spot in finder or binoculars). !! The Andromeda Galaxy - the brightest galaxy in M31 4 G-SAb And 0 hr 43m 41° 16' 40.38 18:09 287.43 xx:xx xx:xx xx:xx 4.8 178 the sky, 4° wide. Look for dust lanes. (The smallest Messier RA gap is between M31 and M32.) The closest companion to M31 - located slightly S M32 5 G-E5pec And 0 hr 43m 40° 52' 40.11 18:09 287.04 xx:xx xx:xx xx:xx 8.7 8x6 of M31 and visible in the same low power field.
    [Show full text]
  • An Ultra-Deep Survey of Low Surface Brightness Galaxies in Virgo
    ' $ An Ultra-Deep Survey of Low Surface Brightness Galaxies in Virgo Elizabeth Helen (Lesa) Moore, BSc(Hons) Department of Physics Macquarie University May 2008 This thesis is presented for the degree of Master of Philosophy in Physics & % iii Dedicated to all the sentient beings living in galaxies in the Virgo Cluster iv CONTENTS Synopsis : :::::::::::::::::::::::::::::::::::::: xvii Statement by Candidate :::::::::::::::::::::::::::::: xviii Acknowledgements ::::::::::::::::::::::::::::::::: xix 1. Introduction ::::::::::::::::::::::::::::::::::: 1 2. Low Surface Brightness (LSB) Galaxies :::::::::::::::::::: 5 2.1 Surface Brightness and LSB Galaxies De¯ned . 6 2.2 Physical Properties and Morphology . 8 2.3 Cluster and Field Distribution of LSB Dwarfs . 14 2.4 Galaxies, Cosmology and Clustering . 16 3. Galaxies and the Virgo Cluster :::::::::::::::::::::::: 19 3.1 Importance of the Virgo Cluster . 19 3.2 Galaxy Classi¯cation . 20 3.3 Virgo Galaxy Surveys and Catalogues . 24 3.4 Properties of the Virgo Cluster . 37 3.4.1 Velocity Distribution in the Direction of the Virgo Cluster . 37 3.4.2 Distance and 3D Structure . 38 vi Contents 3.4.3 Galaxy Population . 42 3.4.4 The Intra-Cluster Medium . 45 3.4.5 E®ects of the Cluster Environment . 47 4. Virgo Cluster Membership and the Luminosity Function :::::::::: 53 4.1 The Schechter Luminosity Function . 54 4.2 The Dwarf-to-Giant Ratio (DGR) . 58 4.3 Galaxy Detection . 59 4.4 Survey Completeness . 62 4.5 Virgo Cluster Membership . 63 4.5.1 Radial Velocities . 64 4.5.2 Morphology . 65 4.5.3 Concentration Parameters . 66 4.5.4 Scale Length Limits . 68 4.5.5 The Rines-Geller Threshold .
    [Show full text]
  • ON the PROGENITORS of TWO TYPE II-P SUPERNOVAE in the VIRGO CLUSTER1,2 Weidong Li,3 Xiaofeng Wang,3,4 Schuyler D
    The Astrophysical Journal, 661:1013 Y 1024, 2007 June 1 # 2007. The American Astronomical Society. All rights reserved. Printed in U.S.A. ON THE PROGENITORS OF TWO TYPE II-P SUPERNOVAE IN THE VIRGO CLUSTER1,2 Weidong Li,3 Xiaofeng Wang,3,4 Schuyler D. Van Dyk,5 Jean-Charles Cuillandre,6 Ryan J. Foley,3 and Alexei V. Filippenko3 Received 2007 January 2; accepted 2007 February 14 ABSTRACT Direct identification of the progenitors of supernovae (SNe) is rare because of the required spatial resolution and depth of the archival data prior to the SN explosions. Here we report on the identification of the progenitors of two nearby SNe in the Virgo Cluster: SN 2006my in NGC 4651 and SN 2006ov in M61. We obtained high-quality ground-based images of SN 2006my with the Canada-France-Hawaii Telescope, and are able to locate the site of the SN on pre-SN Hubble Space Telescope (HST ) Wide Field Planetary Camera 2 images to a high precision (1 uncer- tainty of Æ0.0500). We pinpoint the site of SN 2006ov to within 0.0200 from HSTAdvanced Camera for Surveys images of the SN. We detected a red supergiant progenitor for each SN within the error circles, with an inferred zero-age main- sequence mass (M )of10þ5 and 15þ5 M for the progenitors of SNe 2006my and 2006ov, respectively. The mass zams À3 À3 estimates for the progenitors of both SNe confirm a suggested trend that the most common Type IIYplateau SNe Y originate from low-mass supergiants with Mzams 8 20 M .
    [Show full text]
  • DGSAT: Dwarf Galaxy Survey with Amateur Telescopes
    Astronomy & Astrophysics manuscript no. arxiv30539 c ESO 2017 March 21, 2017 DGSAT: Dwarf Galaxy Survey with Amateur Telescopes II. A catalogue of isolated nearby edge-on disk galaxies and the discovery of new low surface brightness systems C. Henkel1;2, B. Javanmardi3, D. Mart´ınez-Delgado4, P. Kroupa5;6, and K. Teuwen7 1 Max-Planck-Institut f¨urRadioastronomie, Auf dem H¨ugel69, 53121 Bonn, Germany 2 Astronomy Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia 3 Argelander Institut f¨urAstronomie, Universit¨atBonn, Auf dem H¨ugel71, 53121 Bonn, Germany 4 Astronomisches Rechen-Institut, Zentrum f¨urAstronomie, Universit¨atHeidelberg, M¨onchhofstr. 12{14, 69120 Heidelberg, Germany 5 Helmholtz Institut f¨ur Strahlen- und Kernphysik (HISKP), Universit¨at Bonn, Nussallee 14{16, D-53121 Bonn, Germany 6 Charles University, Faculty of Mathematics and Physics, Astronomical Institute, V Holeˇsoviˇck´ach 2, CZ-18000 Praha 8, Czech Republic 7 Remote Observatories Southern Alps, Verclause, France Received date ; accepted date ABSTRACT The connection between the bulge mass or bulge luminosity in disk galaxies and the number, spatial and phase space distribution of associated dwarf galaxies is a dis- criminator between cosmological simulations related to galaxy formation in cold dark matter and generalised gravity models. Here, a nearby sample of isolated Milky Way- class edge-on galaxies is introduced, to facilitate observational campaigns to detect the associated families of dwarf galaxies at low surface brightness. Three galaxy pairs with at least one of the targets being edge-on are also introduced. Approximately 60% of the arXiv:1703.05356v2 [astro-ph.GA] 19 Mar 2017 catalogued isolated galaxies contain bulges of different size, while the remaining objects appear to be bulgeless.
    [Show full text]
  • 2 0 0 3MNRAS.34 6.1215B Mon. Not. R. Astron. Soc. 346,1215-1230
    Mon. Not. R. Astron. Soc. 346,1215-1230 (2003) 6.1215B The star formation rate in dise galaxies: thresholds 3MNRAS.34 0 and dependence on gas amount 0 2 S. Boissier,1* N. Prantzos,2 A. Boselli3 and G. Gavazzi4 1 Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101, USA 2Institut d’Astrophysique de Paris, 98bis BdArago, 75104 Paris, France 2Laboratoire d’Astrophysique de Marseille, Traverse du Siphon, F-13376 Marseille Cedex 12, France 4 Universita degli Studi di Milano, Bicocca, Pizza delTAteneo Nuovo 1, 20126 Milano, Italy Accepted 2003 September 3. Received 2003 September 2; in original form 2003 July 22 ABSTRACT We reassess the applicability of the Toomre criterion in galactic discs and we study the local star formation law in 16 disc galaxies for which abundance gradients are published. The data we use consist of stellar light profiles, atomic and molecular gas (deduced from CO with a metallicity-dependent conversion factor), star formation rates (from Ha emissivities), metal- licities, dispersion velocities and rotation curves. We show that the Toomre criterion applies successfully to the case of the Milky Way disc, but it has limited success with the data of our sample; depending on whether or not the stellar component is included in the stability analysis, we find average values for the threshold ratio of the gas surface density to the critical surface density in the range 0.5-0.7. We also test various star formation laws proposed in the literature, i.e. either the simple Schmidt law or modifications of it, that take into account dynamical fac- tors.
    [Show full text]