Publications of the David Dunlap Observatory- University of Toronto
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The HERACLES View of the H -To-HI Ratio in Galaxies
The HERACLES View of the H2-to-HI Ratio in Galaxies Adam Leroy (NRAO, Hubble Fellow) Fabian Walter, Frank Bigiel, the HERACLES and THINGS teams The Saturday Morning Summary • Star formation rate vs. gas relation on ~kpc scales breaks apart into: A relatively universal CO-SFR relation in nearby disks Systematic environmental scalings in the CO-to-HI ratio • The CO-to-HI ratio is a strong function of radius, total gas, and stellar surface density correlated with ISM properties: dust-to-gas ratio, pressure harder to link to dynamics: gravitational instability, arms • Interpretation: the CO-to-HI ratio traces the efficiency of GMC formation Density and dust can explain much of the observed behavior heracles Fabian Walter Erik Rosolowsky MPIA UBC Frank Bigiel Eva Schinnerer UC Berkeley THINGS plus… MPIA Elias Brinks Antonio Usero Gaelle Dumas U Hertfordshire OAN, Madrid MPIA Erwin de Blok Andreas Schruba Helmut Wiesemeyer U Cape Town IRAM … MPIA Rob Kennicutt Axel Weiss Karl Schuster Cambridge MPIfR IRAM Barry Madore Carsten Kramer Karin Sandstrom Carnegie IRAM MPIA Michele Thornley Daniela Calzetti Kelly Foyle Bucknell UMass MPIA Collaborators The HERA CO-Line Extragalactic Survey First maps Leroy et al. (2009) • IRAM 30m Large Program to map CO J = 2→1 line • Instrument: HERA receiver array operating at 230 GHz • 47 galaxies: dwarfs to starbursts and massive spirals -2 • Very wide-field (~ r25) and sensitive (σ ~ 1-2 Msun pc ) NGS The HI Nearby Galaxy Survey HI Walter et al. (2008), AJ Special Issue (2008) • VLA HI maps of 34 galaxies: -
The Young Stellar Population of IC 1613 III
A&A 551, A74 (2013) Astronomy DOI: 10.1051/0004-6361/201219977 & c ESO 2013 Astrophysics The young stellar population of IC 1613 III. New O-type stars unveiled by GTC-OSIRIS,, M. Garcia1,2 and A. Herrero1,2 1 Instituto de Astrofísica de Canarias, C/Vía Láctea s/n, 38200 La Laguna, Tenerife, Spain e-mail: [email protected] 2 Departamento de Astrofísica, Universidad de La Laguna, Avda. Astrofísico Francisco Sánchez, s/n, 38071 La Laguna, Tenerife, Spain Received 9 July 2012 / Accepted 16 November 2012 ABSTRACT Context. Very low-metallicity massive stars are key to understanding the reionization epoch. Radiation-driven winds, chief agents in the evolution of massive stars, are consequently an important ingredient in our models of the early-Universe. Recent findings hint that the winds of massive stars with poorer metallicity than the SMC may be stronger than predicted by theory. Besides calling the paradigm of radiation-driven winds into question, this result would affect the calculated ionizing radiation and mechanical feedback of massive stars, as well as the role these objects play at different stages of the Universe. Aims. The field needs a systematic study of the winds of a large sample of very metal-poor massive stars. The sampling of spectral types is particularly poor in the very early types. This paper’s goal is to increase the list of known O-type stars in the dwarf irregular galaxy IC 1613, whose metallicity is lower than the SMC’s roughly by a factor 2. Methods. Using the reddening-free Q pseudo-colour, evolutionary masses, and GALEX photometry, we built a list of very likely O-type stars. -
1. Introduction
THE ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 122:109È150, 1999 May ( 1999. The American Astronomical Society. All rights reserved. Printed in U.S.A. GALAXY STRUCTURAL PARAMETERS: STAR FORMATION RATE AND EVOLUTION WITH REDSHIFT M. TAKAMIYA1,2 Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637; and Gemini 8 m Telescopes Project, 670 North Aohoku Place, Hilo, HI 96720 Received 1998 August 4; accepted 1998 December 21 ABSTRACT The evolution of the structure of galaxies as a function of redshift is investigated using two param- eters: the metric radius of the galaxy(Rg) and the power at high spatial frequencies in the disk of the galaxy (s). A direct comparison is made between nearby (z D 0) and distant(0.2 [ z [ 1) galaxies by following a Ðxed range in rest frame wavelengths. The data of the nearby galaxies comprise 136 broad- band images at D4500A observed with the 0.9 m telescope at Kitt Peak National Observatory (23 galaxies) and selected from the catalog of digital images of Frei et al. (113 galaxies). The high-redshift sample comprises 94 galaxies selected from the Hubble Deep Field (HDF) observations with the Hubble Space Telescope using the Wide Field Planetary Camera 2 in four broad bands that range between D3000 and D9000A (Williams et al.). The radius is measured from the intensity proÐle of the galaxy using the formulation of Petrosian, and it is argued to be a metric radius that should not depend very strongly on the angular resolution and limiting surface brightness level of the imaging data. It is found that the metric radii of nearby and distant galaxies are comparable to each other. -
Age and Interstellar Absorption in Young Star-Formation Regions In
ISSN 1063-7729, Astronomy Reports, 2008, Vol. 52, No. 9, pp. 714–728. c Pleiades Publishing, Ltd., 2008. Original Russian Text c A.S. Gusev, V.I. Myakutin, A.E. Piskunov, F.K. Sakhibov, M.S. Khramtsova, 2008, published in Astronomicheski˘ı Zhurnal, 2008, Vol. 85, No. 9, pp. 794–809. Age and Interstellar Absorption in Young Star-Formation Regions in the Galaxies NGC 1068, NGC 4449, NGC 4490, NGC 4631, and NGC 4656/57 Derived from Multicolor Photometry A. S. Gusev1, V.I.Myakutin2, A.E.Piskunov2,F.K.Sakhibov3, 4,andM.S.Khramtsova5 1Sternberg Astronomical Institute, Universitetski ˘ı pr. 13, Moscow, 119991, Russia 2Institute of Astronomy, Russian Academy of Sciences, ul. Pyatnitskaya 48, Moscow, 109017 Russia 3Giessen–Friedberg University for Applied Studies, Friedberg, Germany 4Institute of Astrophysics, Academy of Sciences of Tajikistan, ul. Bukhoro 22, Dushanbe, 734670 Tajikistan 5Ural State University, pr. Lenina 51, Yekaterinburg, 620083 Received October 3, 2007; in final form, October, 26, 2007 Abstract—We have compared the results of multicolor UBVR and Hα photometry for 169 young star-formation complexes in five galaxies using a grid of evolutionary models for young star clusters. The ages and interstellar absorptions are estimated for 102 star-formation complexes with the standard m uncertainties σt =0.30 dex and σAV =0.45 . The accuracies of these parameters were verified using numerical simulations. PACS num b e r s : 98.52.Nr, 98.62.Ai, 97.10.Bt DOI: 10.1134/S1063772908090035 1. INTRODUCTION several evolutionary models, instead considering a set The evolution of galaxies depends on their history of models encompassing the entire interval of the of star formation, i.e., the history of variations of IMF and SFR. -
Probing the Birth of Super Star Clusters
Probing the Birth of Super Star Clusters Kelsey Johnson With help from: Alan Aversa, Crystal Brogan, Rosie Chen, Jeremy Darling, Miller Goss, Remy Indebetouw, Amanda Kepley, Chip Kobulnicky, Amy Reines, Bill Vacca, David Whelan NOAO Summer Program 1995 Remy Regina Indebetouw Jorgenson Angelle Tanner Seth Redfield Reed Riddle Kelsey Johnson Amy Winebarger Super Star Clusters: Cluster formaon in the Extreme • Plausibly proto‐globular clusters • Formaon common in early universe • Impact on the ISM & IGM 1) What physical conditions are required to form these clusters? 2) Does this extreme environment affect affect the SF process itself? Strategy: Look for sources with similar SEDs to Ultracompact HII regions Compact, “inverted spectrum” sources Very dense HII regions non-thermal Sn free-free optically-thick free-free 100 1 l (cm) Wood & Churchwell 1989 II ZW 40 NGC 4490 NGC 4449 Aversa et al.sub Image credit: Michael Gariepy/ Kepley et al. in prep, Beck et et al. Adam Block/NOAO/AURA/NSF Reines et al. 08 NGC 2537 NGC 5253 NGC 3125 Aversa et al. sub Turner et al. 00 Aversa et al. sub Image Credit: Sloan Digital Sky Survey Image credit: Angel Lopez-Sanchez Haro 3 IC 4662 NGC 4214 Beck et al. 00 Image Credit: NASA and Hubble Heritage Team (STScI) Johnson et al. 03 Johnson et al. 04 Natal Clusters are rare! (i.e. short‐lived) Recent radio survey of nearby “star-forming” galaxies: Only 9/28 have detected thermal sources Aversa, Johnson, et al.submitted Henize 2-10 ACS optical, Vacca et al. in prep NICMOS Pa a, Reines et al. -
Astronomy Magazine Special Issue
γ ι ζ γ δ α κ β κ ε γ β ρ ε ζ υ α φ ψ ω χ α π χ φ γ ω ο ι δ κ α ξ υ λ τ μ β α σ θ ε β σ δ γ ψ λ ω σ η ν θ Aι must-have for all stargazers η δ μ NEW EDITION! ζ λ β ε η κ NGC 6664 NGC 6539 ε τ μ NGC 6712 α υ δ ζ M26 ν NGC 6649 ψ Struve 2325 ζ ξ ATLAS χ α NGC 6604 ξ ο ν ν SCUTUM M16 of the γ SERP β NGC 6605 γ V450 ξ η υ η NGC 6645 M17 φ θ M18 ζ ρ ρ1 π Barnard 92 ο χ σ M25 M24 STARS M23 ν β κ All-in-one introduction ALL NEW MAPS WITH: to the night sky 42,000 more stars (87,000 plotted down to magnitude 8.5) AND 150+ more deep-sky objects (more than 1,200 total) The Eagle Nebula (M16) combines a dark nebula and a star cluster. In 100+ this intense region of star formation, “pillars” form at the boundaries spectacular between hot and cold gas. You’ll find this object on Map 14, a celestial portion of which lies above. photos PLUS: How to observe star clusters, nebulae, and galaxies AS2-CV0610.indd 1 6/10/10 4:17 PM NEW EDITION! AtlAs Tour the night sky of the The staff of Astronomy magazine decided to This atlas presents produce its first star atlas in 2006. -
The Extragalactic Distance Scale
The Extragalactic Distance Scale Published in "Stellar astrophysics for the local group" : VIII Canary Islands Winter School of Astrophysics. Edited by A. Aparicio, A. Herrero, and F. Sanchez. Cambridge ; New York : Cambridge University Press, 1998 Calibration of the Extragalactic Distance Scale By BARRY F. MADORE1, WENDY L. FREEDMAN2 1NASA/IPAC Extragalactic Database, Infrared Processing & Analysis Center, California Institute of Technology, Jet Propulsion Laboratory, Pasadena, CA 91125, USA 2Observatories, Carnegie Institution of Washington, 813 Santa Barbara St., Pasadena CA 91101, USA The calibration and use of Cepheids as primary distance indicators is reviewed in the context of the extragalactic distance scale. Comparison is made with the independently calibrated Population II distance scale and found to be consistent at the 10% level. The combined use of ground-based facilities and the Hubble Space Telescope now allow for the application of the Cepheid Period-Luminosity relation out to distances in excess of 20 Mpc. Calibration of secondary distance indicators and the direct determination of distances to galaxies in the field as well as in the Virgo and Fornax clusters allows for multiple paths to the determination of the absolute rate of the expansion of the Universe parameterized by the Hubble constant. At this point in the reduction and analysis of Key Project galaxies H0 = 72km/ sec/Mpc ± 2 (random) ± 12 [systematic]. Table of Contents INTRODUCTION TO THE LECTURES CEPHEIDS BRIEF SUMMARY OF THE OBSERVED PROPERTIES OF CEPHEID -
The RHN Bulletin October-07
THE BULLETIN October 2007 No. 466 2005-2006 EXECUTIVE President Marianne Yake . 905-883-3047 Events calendar [email protected] Past President Natalie Helferty Botany Group Meeting Monday November 5, 2007. 12:30pm & Speakers [email protected] 2nd Vice President -- Position Available -- Executive Meeting Tuesday November 13, 2007. 7:30pm Secretary -- Position Available -- Where: Robert Holland Centre Treasurer Gene Denzel [email protected] Bird Goup Meeting Wednesday November 14, 2007. 7:30pm th 50 Anniversary Michael White Topic: Vesper Sparrow and Field Sparrow Field Trips Tom Waechter Host: Theo Hofmann, 199 Arnold Av. Thornhill [email protected] Environment -- Position Available -- General Meeting Thursday November 15, 2007. 7:30pm Publicity Nancy Zalman [email protected] Joint meeting with West Humber Naturalists Bulletin Editor Lloyd Helferty . 905-707-8754 Speaker: Anne Parker [email protected] Topic: An Inconvenient Truth–Climate Change Membership Mike Turk Location: Richmond Hill Presbyterian Church, [email protected] Wallace Hall. 10066 Yonge St. Events -- Position Available – Ontario Nature Rep Diana Piché -- Reminder: There is NO meeting in December -- Website coordinator Rod Potter [email protected] Check for more Events and Outings on Page 2 Gladys McLatchy Fall is always welcomed to the Richmond Hill Naturalists members and friends. It is a time to embark on work and play and set out the future for our membership. Our annual corn roast has been hosted for 44 years at Russell Tilt’s home, and we greatly acknowledge the work he has done for our club and the community. We were able to enjoy and catch up with each other after our summer. -
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. -
Neutral Hydrogen in Dwarf Galaxies
A&A 389, 29–41 (2002) Astronomy DOI: 10.1051/0004-6361:20020352 & c ESO 2002 Astrophysics Neutral hydrogen in dwarf galaxies I. The spatial distribution of HI J. M. Stil1,2 andF.P.Israel1 1 Sterrewacht Leiden, PO Box 9513, 2300 RA Leiden, The Netherlands 2 Physics Department, Queen’s University, Kingston ON K7L 4P1, Canada Received 13 December 2001 / Accepted 1 March 2002 Abstract. This paper is the first in a series presenting a sample of 30 late-type dwarf galaxies, observed with the Westerbork Synthesis Radio Telescope (WSRT) in the 21-cm line of neutral atomic hydrogen (HI). The sample itself, the HI content of and the HI distribution in the sample galaxies are briefly discussed. Four sample galaxies were also detected in the continuum. Key words. galaxies: irregular – galaxies: dwarf 1. Introduction those galaxies that are in the northern hemisphere, i.e. have declinations above 14◦ (soastobeobservablewith Galaxies come in a wide variety of shapes and sizes. The the WSRT). There is no single unambiguous definition larger galaxies are usually accompanied by a number of of a dwarf galaxy. Often, a galaxy is considered to be a smaller (dwarf) galaxies, although dwarf galaxies also oc- dwarf if its absolute luminosity corresponds to the light of cur by themselves. Late-type dwarf galaxies are generally no more than half a billion suns (M > −16), about one rich in neutral atomic hydrogen (HI) gas, usually more B per cent of the luminosity of a spiral galaxy such as the so than much larger late type spiral galaxies. Their opti- Milky Way or M 31. -
What's in This Issue?
A JPL Image of surface of Mars, and JPL Ingenuity Helicioptor illustration. July 11th at 4:00 PM, a family barbeque at HRPO!!! This is in lieu of our regular monthly meeting.) (Monthly meetings are on 2nd Mondays at Highland Road Park Observatory) This is a pot-luck. Club will provide briskett and beverages, others will contribute as the spirit moves. What's In This Issue? President’s Message Member Meeting Minutes Business Meeting Minutes Outreach Report Asteroid and Comet News Light Pollution Committee Report Globe at Night SubReddit and Discord BRAS Member Astrophotos ARTICLE: Astrophotography with your Smart Phone Observing Notes: Canes Venatici – The Hunting Dogs Like this newsletter? See PAST ISSUES online back to 2009 Visit us on Facebook – Baton Rouge Astronomical Society BRAS YouTube Channel Baton Rouge Astronomical Society Newsletter, Night Visions Page 2 of 23 July 2021 President’s Message Hey everybody, happy fourth of July. I hope ya’ll’ve remembered your favorite coping mechanism for dealing with the long hot summers we have down here in the bayou state, or, at the very least, are making peace with the short nights that keep us from enjoying both a good night’s sleep and a productive observing/imaging session (as if we ever could get a long enough break from the rain for that to happen anyway). At any rate, we figured now would be as good a time as any to get the gang back together for a good old fashioned potluck style barbecue: to that end, we’ve moved the July meeting to the Sunday, 11 July at 4PM at HRPO. -
The Properties of Ten O-Type Stars in the Low-Metallicity Galaxies IC 1613, WLM, and NGC 3109?
A&A 572, A36 (2014) Astronomy DOI: 10.1051/0004-6361/201424312 & c ESO 2014 Astrophysics The properties of ten O-type stars in the low-metallicity galaxies IC 1613, WLM, and NGC 3109? F. Tramper1, H. Sana2, A. de Koter1;3, L. Kaper1, and O. H. Ramírez-Agudelo1 1 Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, PO Box 94249, 1090 GE Amsterdam, The Netherlands e-mail: [email protected] 2 ESA/Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 3 Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium Received 30 May 2014 / Accepted 30 September 2014 ABSTRACT Context. Massive stars likely played an important role in the reionization of the Universe, and the formation of the first black holes. They are potential progenitors of long-duration gamma-ray bursts, seen up to redshifts of about ten. Massive stars in low-metallicity environments in the local Universe are reminiscent of their high redshift counterparts, emphasizing the importance of the study of their properties and evolution. In a previous paper, we reported on indications that the stellar winds of low-metallicity O stars may be stronger than predicted, which would challenge the current paradigm of massive star evolution. Aims. In this paper, we aim to extend our initial sample of six O stars in low-metallicity environments by four. The total sample of ten stars consists of the optically brightest sources in IC 1613, WLM, and NGC 3109. We aim to derive their stellar and wind parameters, and compare these to radiation-driven wind theory and stellar evolution models.