Candidate Active Nuclei in Late-Type Spiral Galaxies
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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. -
Spiral Galaxy HI Models, Rotation Curves and Kinematic Classifications
Spiral galaxy HI models, rotation curves and kinematic classifications Theresa B. V. Wiegert A thesis submitted to the Faculty of Graduate Studies of The University of Manitoba in partial fulfillment of the requirements of the degree of Doctor of Philosophy Department of Physics & Astronomy University of Manitoba Winnipeg, Canada 2010 Copyright (c) 2010 by Theresa B. V. Wiegert Abstract Although galaxy interactions cause dramatic changes, galaxies also continue to form stars and evolve when they are isolated. The dark matter (DM) halo may influence this evolu- tion since it generates the rotational behaviour of galactic disks which could affect local conditions in the gas. Therefore we study neutral hydrogen kinematics of non-interacting, nearby spiral galaxies, characterising their rotation curves (RC) which probe the DM halo; delineating kinematic classes of galaxies; and investigating relations between these classes and galaxy properties such as disk size and star formation rate (SFR). To generate the RCs, we use GalAPAGOS (by J. Fiege). My role was to test and help drive the development of this software, which employs a powerful genetic algorithm, con- straining 23 parameters while using the full 3D data cube as input. The RC is here simply described by a tanh-based function which adequately traces the global RC behaviour. Ex- tensive testing on artificial galaxies show that the kinematic properties of galaxies with inclination > 40 ◦, including edge-on galaxies, are found reliably. Using a hierarchical clustering algorithm on parametrised RCs from 79 galaxies culled from literature generates a preliminary scheme consisting of five classes. These are based on three parameters: maximum rotational velocity, turnover radius and outer slope of the RC. -
CONSTELLATION TRIANGULUM, the TRIANGLE Triangulum Is a Small Constellation in the Northern Sky
CONSTELLATION TRIANGULUM, THE TRIANGLE Triangulum is a small constellation in the northern sky. Its name is Latin for "triangle", derived from its three brightest stars, which form a long and narrow triangle. Known to the ancient Babylonians and Greeks, Triangulum was one of the 48 constellations listed by the 2nd century astronomer Ptolemy. The celestial cartographers Johann Bayer and John Flamsteed catalogued the constellation's stars, giving six of them Bayer designations. The white stars Beta and Gamma Trianguli, of apparent magnitudes 3.00 and 4.00, respectively, form the base of the triangle and the yellow-white Alpha Trianguli, of magnitude 3.41, the apex. Iota Trianguli is a notable double star system, and there are three star systems with planets located in Triangulum. The constellation contains several galaxies, the brightest and nearest of which is the Triangulum Galaxy or Messier 33—a member of the Local Group. The first quasar ever observed, 3C 48, also lies within Triangulum's boundaries. HISTORY AND MYTHOLOGY In the Babylonian star catalogues, Triangulum, together with Gamma Andromedae, formed the constellation known as MULAPIN "The Plough". It is notable as the first constellation presented on (and giving its name to) a pair of tablets containing canonical star lists that were compiled around 1000 BC, the MUL.APIN. The Plough was the first constellation of the "Way of Enlil"—that is, the northernmost quarter of the Sun's path, which corresponds to the 45 days on either side of summer solstice. Its first appearance in the pre-dawn sky (heliacal rising) in February marked the time to begin spring ploughing in Mesopotamia. -
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. -
The Suzaku Broadband X-Ray Spectrum of the Dwarf Seyfert Galaxy NGC 4395 K
A&A 514, A58 (2010) Astronomy DOI: 10.1051/0004-6361/200912431 & c ESO 2010 Astrophysics The Suzaku broadband X-ray spectrum of the dwarf Seyfert galaxy NGC 4395 K. Iwasawa1,, Y. Tanaka2, and L. C. Gallo3 1 INAF-Ossservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy e-mail: [email protected] 2 Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße 1, 85748 Garching, Germany e-mail: [email protected] 3 Department of Astronomy and Physics, Saint Mary’s University, Halifax, NS B3H 3C3, Canada e-mail: [email protected] Received 6 May 2009 / Accepted 21 December 2009 ABSTRACT 5 We present a Suzaku observation of the dwarf Seyfert galaxy NGC 4395 with an estimated black hole mass of ∼10 M. Rapid and strong X-ray variability with an rms amplitude of ∼60 per cent is observed in the 0.4–10 keV band with the XIS cameras. The shape of the light curve appears to depend on energies. The hard X-ray emission is detected up to 35 keV with the HXD-PIN detector at a similar flux level as observed with the INTEGRAL IBIS. The X-ray spectrum below 10 keV is strongly absorbed by partially ionized (ξ ∼ 35 erg s cm−1) gas with a mean equivalent hydrogen column density of ∼2 × 1022 cm−2, when a simple absorption model is applied. The spectral shape is also strongly variable but not a simple function of the source brightness. The spectral variability appears to be accounted for mainly by continuum slope changes, but variability in the ionized absorber may also play some part. -
Deep Submillimeter Images of NGC 7331; Dust at the Periphery of Spiral Disks
A&A 366, 451–465 (2001) Astronomy DOI: 10.1051/0004-6361:20000405 & c ESO 2001 Astrophysics Deep submillimeter images of NGC 7331; dust at the periphery of spiral disks P. B. Alton1, J. Lequeux2, S. Bianchi3, D. Churches1,J.Davies1, and F. Combes2 1 Department of Physics & Astronomy, University of Wales, PO Box 913, Cardiff CF2 3YB, UK 2 DEMIRM, Observatoire de Paris, 61 avenue de l’Observatoire, 75014 Paris, France 3 ESO, Karl-Schwarzschild-Strasse 2, 85748 Garching bei Muenchen, Germany Received 11 September 2000 / Accepted 29 November 2000 Abstract. We present deep 450 and 850 µm SCUBA images of the nearby spiral galaxy NGC 7331. Using the submillimeter emissivity inferred from COBE observations of Milky Way dust, we convert our SCUBA images into maps of optical depth. The opacity derived in this way is quite low at the visible limit of NGC 7331 (τB ≤ 0.22 at the R25 radius for the disk seen face-on). In a similar fashion, we exploit SCUBA and ISOPHOT images of a further 10 galaxies and, collectively, these data indicate τB =0.1–0.2attheR25 radius. Our constraints on disk opacity are fed into a simulation of how light emanating from high redshifts is attenuated by foreground spirals. In making this calculation, we consider the possibility that galactic disks may have also contained different dust masses in the past. We estimate that less than 10% of the light emitted by Hubble Deep Field galaxies fails to reach the B-band observer due to intervening spirals. Key words. ISM: dust, extinction – ISM: molecules – galaxies: spiral – galaxies: ISM – infrared: galaxies – galaxies: NGC 7331 1. -
Cold Gas and Baryon-Induced Dark Matter Cores in Nearby Galaxies
Cold gas and baryon-induced dark matter cores in nearby galaxies Flor Allaert Supervisors: Prof. Dr. Maarten Baes, Dr. Gianfranco Gentile A dissertation submitted to Ghent University in partial fulfilment of the requirements for the degree of Doctor of Science: Astronomy September 2017 Supervisors: Prof. Dr. Maarten Baes Vakgroep Fysica en Sterrenkunde Universiteit Gent Dr. Gianfranco Gentile Vakgroep Fysica en Sterrenkunde Vrije Universiteit Brussel Jury members: Prof. Dr. Dirk Poelman (President) Vakgroep Vastestofwetenschappen Universiteit Gent Dr. Karel Van Acoleyen (Secretary) Vakgroep Fysica en Sterrenkunde Universiteit Gent Prof. Dr. Sven De Rijcke Vakgroep Fysica en Sterrenkunde Universiteit Gent Prof. Dr. Herwig Dejonghe Vakgroep Fysica en Sterrenkunde Universiteit Gent Prof. Dr. Uli Klein Argelander-Institut fur¨ Astronomie Universitat¨ Bonn Prof. Dr. Erwin de Blok Netherlands Institute for Radio Astronomy Contents 1 Introduction1 1.1 Galaxies - building blocks of the Universe.................1 1.1.1 Classification............................2 1.1.2 Chemical evolution.........................4 1.1.3 Accretion and mergers.......................6 1.2 Observing the different components....................8 1.2.1 Stars................................8 1.2.2 Gas.................................9 1.2.3 Dust................................. 12 1.3 Panchromatic SED modelling and dust radiative transfer......... 13 1.3.1 SED fitting............................. 13 1.3.2 Dust radiative transfer....................... 14 1.3.3 The energy balance problem.................... 15 1.4 FRIEDL, HEROES and NHEMESES................... 17 1.4.1 The energy balance problem revisited............... 18 1.5 Dark matter................................. 18 1.5.1 History............................... 19 1.5.2 Dark matter in cosmology..................... 21 1.5.3 Cosmological simulations..................... 23 1.5.4 The cusp-core controversy..................... 24 1.5.5 Baryons to the rescue?...................... -
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. -
Torus Model Properties of an Ultra-Hard X-Ray Selected Sample of Seyfert Galaxies.', Monthly Notices of the Royal Astronomical Society., 486 (4)
Durham Research Online Deposited in DRO: 16 July 2019 Version of attached le: Published Version Peer-review status of attached le: Peer-reviewed Citation for published item: Garc¡a-Bernete,I. and RamosAlmeida, C. and Alonso-Herrero, A. and Ward, M. J. and Acosta-Pulido, J. A. and Pereira-Santaella, M. and Hern¡an-Caballero,A. and AsensioRamos, A. and Gonz¡alez-Mart¡n,O. and Levenson, N. A. and Mateos, S. and Carrera, F. J. and Ricci, C. and Roche, P. and Marquez, I. and Packham, C. and Masegosa, J. and Fuller, L. (2019) 'Torus model properties of an ultra-hard X-ray selected sample of Seyfert galaxies.', Monthly notices of the Royal Astronomical Society., 486 (4). pp. 4917-4935. Further information on publisher's website: https://doi.org/10.1093/mnras/stz1003 Publisher's copyright statement: c 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. Additional information: Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full DRO policy for further details. Durham University Library, Stockton Road, Durham DH1 3LY, United Kingdom Tel : +44 (0)191 334 3042 | Fax : +44 (0)191 334 2971 https://dro.dur.ac.uk MNRAS 486, 4917–4935 (2019) doi:10.1093/mnras/stz1003 Advance Access publication 2019 April 10 Torus model properties of an ultra-hard X-ray selected sample of Seyfert galaxies I. -
Arxiv:0907.4718V1 [Astro-Ph.GA] 27 Jul 2009 Nnab Aais Hi Ihlmnste ( Luminosities High Their Objects Point-Like Galaxies
Submitted to Astrophysical Journal A Preprint typeset using L TEX style emulateapj v. 04/03/99 ULTRALUMINOUS X-RAY SOURCE CORRELATIONS WITH STAR-FORMING REGIONS Douglas A. Swartz1 Allyn F. Tennant2, and Roberto Soria3 Submitted to Astrophysical Journal ABSTRACT Maps of low-inclination nearby galaxies in Sloan Digitized Sky Survey u − g, g − r and r − i colors are used to determine whether Ultraluminous X-ray sources (ULXs) are predominantly associated with star-forming regions of their host galaxies. An empirical selection criterion is derived from colors of H ii regions in M 81 and M 101 that differentiates between the young, blue stellar component and the older disk and bulge population. This criterion is applied to a sample of 58 galaxies of Hubble type S0 and later and verified through an application of Fisher’s linear discriminant analysis. It is found that 60% (49%) of ULXs in optically-bright environments are within regions blueward of their host galaxy’s H ii regions compared to only 27% (0%) of a control sample according to the empirical (Fisher) criterion. This is an excess of 3σ above the 32% (27%) expected if the ULXs were randomly distributed within their galactic hosts. This indicates a ULX preference for young, ∼<10 Myr, OB associations. However, none of the ULX environments have the morphology and optical brightness suggestive of a massive young super star cluster though several are in extended or crowded star-forming (blue) environments that may contain clusters unresolved by Sloan imaging. Ten of the 12 ULX candidates with estimated X-ray luminosities in excess of 3×1039 ergs s−1 are equally divided among the group of ULX environments redward of H ii regions and the group of optically faint regions. -
Synapses of Active Galactic Nuclei: Comparing X-Ray and Optical Classifications Using Artificial Neural Networks?
A&A 567, A92 (2014) Astronomy DOI: 10.1051/0004-6361/201322592 & c ESO 2014 Astrophysics Synapses of active galactic nuclei: Comparing X-ray and optical classifications using artificial neural networks? O. González-Martín1;2;??, D. Díaz-González3, J. A. Acosta-Pulido1;2, J. Masegosa4, I. E. Papadakis5;6, J. M. Rodríguez-Espinosa1;2, I. Márquez4, and L. Hernández-García4 1 Instituto de Astrofísica de Canarias (IAC), C/Vía Láctea s/n, 38205 La Laguna, Spain e-mail: [email protected] 2 Departamento de Astrofísica, Universidad de La Laguna (ULL), 38205 La Laguna, Spain 3 Shidix Technologies, 38320, La Laguna, Spain 4 Instituto de Astrofísica de Andalucía, CSIC, C/ Glorieta de la Astronomía s/n, 18005 Granada, Spain 5 Physics Department, University of Crete, PO Box 2208, 710 03 Heraklion, Crete, Greece 6 IESL, Foundation for Research and Technology, 711 10 Heraklion, Crete, Greece Received 2 September 2013 / Accepted 3 April 2014 ABSTRACT Context. Many classes of active galactic nuclei (AGN) have been defined entirely through optical wavelengths, while the X-ray spectra have been very useful to investigate their inner regions. However, optical and X-ray results show many discrepancies that have not been fully understood yet. Aims. The main purpose of the present paper is to study the synapses (i.e., connections) between X-ray and optical AGN classifications. Methods. For the first time, the newly implemented efluxer task allowed us to analyse broad band X-ray spectra of a sample of emission-line nuclei without any prior spectral fitting. Our sample comprises 162 spectra observed with XMM-Newton/pn of 90 lo- cal emission line nuclei in the Palomar sample. -
Pos(10Th EVN Symposium)081 ]), We Have Targeted a Few Additional 3 ∗ [email protected] [email protected] Speaker
More discoveries of compact radio cores in Seyfert galaxies with the EVN PoS(10th EVN Symposium)081 Marcello Giroletti∗ INAF Istituto di Radioastronomia via Gobetti 101, 40129 Bologna (Italy) E-mail: [email protected] Francesca Panessa INAF IASF, via Fosso del Cavaliere 100, 00133 Rome, Italy E-mail: [email protected] Following the high detection rate achieved by EVN observations of the central regions of local Seyfert galaxies (Giroletti & Panessa 2009, ApJL 706, 260, [3]), we have targeted a few additional sources from a complete sample. We have detected three more sources (NGC 3982, NGC 3227, and NGC 4138) at both 1.6 and 5 GHz and present preliminary results. Moreover, the declination of the sources was suitable to include Arecibo in the EVN observations, which provides important clues on the compactness of the emission region. 10th European VLBI Network Symposium and EVN Users Meeting: VLBI and the new generation of radio arrays September 20-24, 2010 Manchester Uk ∗Speaker. c Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. http://pos.sissa.it/ More discoveries of compact radio cores in Seyfert galaxies with the EVN Marcello Giroletti PoS(10th EVN Symposium)081 Figure 1: Combined optical and EVN images of Seyfert galaxies. Clockwise from top left: NGC 4051, NGC 4388, NGC 5033, and NGC 4501. Optical images from Sloan Digital Sky Survey, radio ones from EVN observations at 1.6 GHz ([3], typical beam 10 × 5 mas). 1. Background: recent VLBI observations of local Seyfert galaxies It is a well established fact that radio quiet Active Galactic Nuclei (AGNs) are not radio silent: indeed, VLA observations reveal emission at milliJansky level in most AGNs, even in low- luminosity AGNs [5].