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A Study of 53 Radio Galaxies Selected from the Astronomical Database

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΢ρνιή Θεηηθώλ Δπηζηεκώλ & Σερλνινγίαο Πξνρσξεκέλεο ΢πνπδέο ζηε Φπζηθή (Π΢Φ) Πηπρηαθή / Γηπισκαηηθή Δξγαζία Μειέηε δείγκαηνο 53 ξαδηνπεγώλ από ηε βάζε δεδνκέλσλ Galex, θαη δύν ξαδηνγαιαμηώλ, ησλ Hercules A θαη 3C 310. Ξαλζνύια Σζαγθαιίδνπ Δπηβιέπσλ θαζεγεηήο: Νεθηαξία Γθηδάλε Αμηνινγεηήο Β: Βαζίιεο Υαξκαλδάξεο Πάηξα, Ινύιηνο 2020 Tsagkalidou X., A study of 55 radiosources. Περίληψη ΢ηελ παξνύζα εξγαζία παξνπζηάδνπκε ηε κειέηε ελόο δείγκαηνο 53 ξαδηνπεγώλ, νη νπνίεο βξίζθνληαη ζε ζρεηηθά θνληηλέο απνζηάζεηο, θαη παξνπζηάδνπλ κεηαηόπηζε ζην εξπζξό (redshift) κε ηηκέο από 0,001 έσο 0,008. Έμη εθ ησλ ξαδηνπεγώλ ηνπ δείγκαηνο (νη NGC 6822, LGS 3, Bol 520, Andromeda X, Andromeda XI θαη Andromeda XVI) θαίλεηαη λα έρνπλ αξλεηηθέο ηηκέο redshift, άξα παξνπζηάδνπλ κεηαηόπηζε πξνο ην θπαλό. Η έξεπλα πνπ δηεμήγακε ζηε βηβιηνγξαθία θαηέδεημε όηη 52 από ηα αληηθείκελα ηνπ δείγκαηόο καο είλαη γαιαμίεο, ελώ έλα, ν Bol 520, ζεσξείηαη ζθαηξηθό ζκήλνο (globular cluster) θαη όρη γαιαμίαο. Λακβάλνληαο ππόςε ηηο ηηκέο ππθλόηεηαο καγλεηηθώλ ξνώλ ζηελ πεξηνρή ησλ ξαδηνζπρλνηήησλ πνπ έρνπλ θαηαγξαθεί ζηε βηβιηνγξαθία, πξνρσξήζακε ζηνλ ππνινγηζκό ηεο ηζρύνο 38 γαιαμηώλ εθ ηνπ ζπλόινπ. Γηα λα δηεμάγνπκε ηνπο ππνινγηζκνύο, πηνζεηήζακε ΛCDM θνζκνινγία, κε ηηκέο παξακέηξσλ πνπ θαζνξίζηεθαλ από ηελ ηειεπηαία έθδνζε ηεο απνζηνιήο ηνπ δηαζηεκηθνύ ηειεζθνπίνπ Planck. Από ηα απνηειέζκαηα ησλ ππνινγηζκώλ ζπκπεξαίλνπκε όηη νη 38 γαιαμίεο είλαη ζρεηηθά κηθξήο ηζρύνο ζηελ πεξηνρή ησλ ξαδηνθπκάησλ. Ο ιόγνο γηα ηνλ νπνίν δελ πξνβήθακε ζε εθηηκήζεηο θαη γηα ηηο ππόινηπεο δεθαπέληε ξαδηνπεγέο ηνπ δείγκαηνο ήηαλ ε έιιεηςε θαηάιιεισλ ηηκώλ ππθλνηήησλ ξνώλ, θαζώο ε έξεπλα καο δελ απέδσζε αμηνπνηήζηκεο θαηαγεγξακκέλεο ηηκέο ζηελ πεξηνρή ησλ ξαδηνθπκάησλ. Δθ παξαιιήινπ, αμηνπνηώληαο ηα επξήκαηα ηεο έξεπλάο καο πξνζπαζήζακε λα παξνπζηάζνπκε κία ζύληνκε πεξηγξαθή θάζε ξαδηνπεγήο, εζηηάδνληαο –όπνπ ήηαλ εθηθηό– ζηα ραξαθηεξηζηηθά γλσξίζκαηά ηνπο πνπ είλαη εκθαλή ζηα ξαδηνθύκαηα. Μεγάιν ελδηαθέξνλ παξνπζηάδνπλ δέθα γαιαμίεο, νη νπνίνη ραξαθηεξίδνληαη από ηελ ύπαξμε ελεξγνύ γαιαμηαθνύ ππξήλα, θαζώο θαη έλαο starburst γαιαμίαο, ν NGC 5236. Οη δέθα γαιαμίεο κε ελεξγνύο γαιαμηαθνύο ππξήλεο ηαμηλνκνύληαη σο εμήο: πέληε (νη NGC 4945, NGC 0253, NGC4826, NGC 5322 θαη NGC 4736) είλαη Seyfert γαιαμίεο, δύν (νη Circinus θαη NGC 4136) είλαη ηύπνπ Seyfert I θαη ηξεηο (νη NGC 6744, NGC 2787 θαη NGC 2403) ζεσξνύληαη LINER γαιαμίεο. Ιδηαίηεξα νη NGC 4945, NGC 0253 θαη Circinus απνηεινύλ εμαηξεηηθά ελδηαθέξνληα αληηθείκελα, θαζώο ραξαθηεξίδνληαη από ηε ζπλύπαξμε έληνλεο starburst δξαζηεξηόηεηαο θαη ελεξγνύ γαιαμηαθνύ ππξήλα. Δπηπξνζζέησο, πξνζπαζήζακε λα παξνπζηάζνπκε κηα εκπεξηζηαησκέλε βηβιηνγξαθηθή αλαζθόπεζε δύν κνλαδηθώλ ξαδηνγαιαμηώλ, ηνπ Ηξαθιή Α (3C 348) θαη ηνπ 3C 310 (VV 204). Η ξαδηνεθπνκπή απηώλ ησλ γαιαμηώλ ραξαθηεξίδεηαη από ηελ ύπαξμε δηπιώλ Πηπρηαθή / Γηπισκαηηθή Δξγαζία v Tsagkalidou X., A study of 55 radiosources. ξαδηνινβώλ, ηελ παξνπζία ελεξγνύ γαιαμηαθνύ ππξήλα αιιά έρεη ηελ ηδηαηηεξόηεηα ηεο παξνπζίαο θάπνησλ θνηλώλ –κεηαμύ ηνπο– ραξαθηεξηζηηθώλ, ηα νπνία είλαη αζπλήζηζηα γηα ξαδηνγαιαμίεο θαη ελεξγνύο γαιαμηαθνύο ππξήλεο ελ γέλεη. Η ύπαξμε ησλ ξαδηνινβώλ (jets) ππνδεηθλύεη ηελ ελεξγνπνίεζε ελόο κεραληζκνύ jet-mode θαηά ηελ αλαηξνθνδόηεζε ηνπ ελεξγνύ γαιαμηαθνύ ππξήλα θαη επνκέλσο νπηηθά ραξαθηεξίδνληαη σο low-excitation radio galaxies. Οη καύξεο ηξύπεο πνπ θηινμελνύλ εθηηκώληαη όηη έρνπλ 9 κάδα ηεο ηάμεο ησλ 10 Μ☉ πεξίπνπ γηα ηνλ 3C 348, ελώ γηα ηνλ 3C 310 ε αληίζηνηρε 8 κάδα θαηά πξνζέγγηζε είλαη ηεο ηάμεο ησλ 10 Μ☉. Η βηβιηνγξαθηθή αλαζθόπεζε ησλ Ηξαθιή Α θαη 3C 310 πνπ θάλακε πξνζπαζεί λα παξνπζηάζεη όια ηα ηειεπηαία δεδνκέλα από ην έηνο 2016 κέρξη θαη ζήκεξα. Λέξεις – Κλειδιά Ραδηνπεγέο, GALEX, ξαδηνηζρύο, Ηξαθιήο Α (3C 348), 3C 310 Πηπρηαθή / Γηπισκαηηθή Δξγαζία vi Tsagkalidou X., A study of 55 radiosources. A study of 53 radio sources selected from GALEX and of two radio galaxies, Hercules A and 3C 310. Xanthoula Tsagkalidou Abstract We present a study of 53 relatively nearby radio sources that are characterized by redshifts within the range of 0.001 < z < 0.008. Six radio sources (NGC 6822, LGS 3, Bol 520, Andromeda X, Andromeda XI and Andromeda XVI) demonstrate negative redshift values and therefore are classified as blueshifted. Searching the literature, it became evident that 52 objects in our sample are galaxies and the remaining one, Bol 520, is a globular cluster and not a galaxy. Assuming radio flux density measurements obtained by the literature, we estimated the radio power for 38 of the galaxies, using the concordance cosmological model with cosmological constants obtained by the latest release of the Planck mission. The results showed that they are relatively low-power radio sources. For the remaining 15 radio objects of our sample no flux density measurements exist in the literature that would enable us to estimate their radio powers. We also attempted a brief presentation of each one of the 53 radio objects, especially focusing on their radio properties. Galaxies which present very interesting features, are the starburst galaxy NGC 5236 and ten galaxies that are characterized as active galactic nuclei and are classified as follows: five are Seyfert galaxies (NGC 4945, NGC 0253, NGC4826, NGC 5322, NGC 4736), two (Circinus, NGC 4136) have been identified as Seyfert type I and three (NGC 6744, NGC 2787, NGC 2403) are LINER galaxies. NGC 4945, NGC 0253 and Circinus pose very interesting cases, as they are characterized as composite starburst/active galactic nucleus systems. We have also conducted a literature review concerning the study of two exceptional radio galaxies, Hercules A (3C 348) and 3C 310 (VV 204). The two double-lobed radio galaxies Πηπρηαθή / Γηπισκαηηθή Δξγαζία vii Tsagkalidou X., A study of 55 radiosources. are classified as active galactic nuclei and appear to have features akin to each other that are uncommon to radiogalaxies and active galactic nuclei in general. They appear to be driven by jet-mode mechanisms and are optically designated as low-excitation radio 9 galaxies. They host supermassive black holes with estimated mass of ≃ 10 Μ☉ for 8 Hercules A and ≃ 10 Μ☉ for 3C 310. Our literature review attempted to keep track of the latest data concerning Hercules A and 3C 310, which were published over the last four years to date. Keywords Radiosources, GALEX, radio power, Hercules A (3C 348), 3C 310 Πηπρηαθή / Γηπισκαηηθή Δξγαζία viii Tsagkalidou X., A study of 55 radiosources. References Abdo, A. A., et al., 2010, Fermi Large Area Telescope First Source Catalog, ApJS, 188, 405A Abidin, Z. Z., Umar, R., Ibrahim, Z. A., Rosli, Z., Asanok, K., Gasiprong, N., 2013, Investigation on the Frequency Allocation for Radio Astronomy at the L Band, PASA, 30, 47A Abramowski, A., et al., 2012, Spectral Analysis and Interpretation of the γ-Ray Emission from the Starburst Galaxy NGC 253, ApJ, 757, 158A Adams, E. A. K., & Oosterloo, T. A., 2018, Deep neutral hydrogen observations of Leo T with the Westerbork Synthesis Radio Telescope, A&A, 612, A26 Ade, P.A.R., et al., 2014, Planck 2013 results. XXIX. The Planck catalogue of Sunyaev- Zeldovich sources, A&A, 571, A29 Aghanim, N., et al., 2018, Planck 2018 results. VI. Cosmological parameters, arXiv180706209P Akrami, Y., et al., 2018, Planck intermediate results. LIV. The Planck multi-frequency catalogue of non-thermal sources., A&A, 619A, 94P Alabi, A., et al., 2015, The SLUGGS survey globular cluster kinematics in a `double sigma' galaxy - NGC 4473, MNRAS,452, 2208A Allen, M. G., et al., 2002, Ultraviolet Hubble Space Telescope Snapshot Survey of 3CR Radio Source Counterparts at Low Redshift, ApJS, 139, 411A Argyle, R. W., Clements, E. D., 1990, Optical positions of miscellaneous galaxies. Obs, 110, 93A Baldassare, V. F., Gallo, El., Miller, B. P., Plotkin, R. M., Treu, T., Valluri, M., Woo, J.- H., 2014, AMUSE-Field. II. Nucleation of Early-type Galaxies in the Field versus Cluster Environment, ApJ, 791, 133B Balmaverde, B., et al., 2019, The MURALES survey. II. Presentation of MUSE observations of 20 3C low-z radio galaxies and first results, A&A, 632A, 124 Πηπρηαθή / Γηπισκαηηθή Δξγαζία 153 Tsagkalidou X., A study of 55 radiosources. Barnes, D. G., & de Blok, W. J. G., 2001, On the Neutral Gas Content and Environment of NGC 3109 and the Antlia Dwarf Galaxy, AJ, 122, 825 Baum et al., 1996, Hubble Space Telescope Observations of Obscuration Rings in Hercules A: Implications for Energy Transport in Powerful Radio Galaxies, ApJL., 465, 5 Beck, R., et al., 2002, Magnetic fields in barred galaxies. I. The atlas, A&A, 391, 83B Becker, R. H., White, R. L., Helfand, D. J., 1995, The FIRST Survey: Faint Images of the Radio Sky at Twenty Centimeters, ApJ, 450, 559B Begum, A., Chengalur, J. N., Karachentsev, I. D., Sharina, M. E., 2005, Resolving the mystery of the dwarf galaxy HIZSS003, MNRAS, 359, 53B Ben Bekhti, N., et al., 2016, HI4PI: A full-sky H I survey based on EBHIS and GASS, A&A, 594A,116H Best, P. N., Röttgering, H. J. A., Lehnert, M. D., 1999, A 98 per cent spectroscopically complete sample of the most powerful equatorial radio sources at 408MHz, MNRAS, 310, 223B Best, P. N., Röttgering, H. J. A., Lehnert, M. D., 1999, A 98 per cent spectroscopically complete sample of the most powerful equatorial radio sources at 408MHz, MNRAS, 310, 223B Blandford, R., Meier, D., Readhead, A., 2019, Relativistic Jets from Active Galactic Nuclei, ARA&A, 57, 467B Blitz, L., Robishaw, T., 2000, Gas-Rich Dwarf Spheroidals, ApJ, 541, 675B Boch, T., Fernique, P., 2014, Aladin Lite: Embed your Sky in the Browser, ASPC, 485, 277B Böhringer, H., et al., 2000, The Northern ROSAT All-Sky (NORAS) Galaxy Cluster Survey. I. X-Ray Properties of Clusters Detected as Extended X-Ray Sources, ApJS, 129, 435B Bonnarel, F, et al., 2000, The ALADIN interactive sky atlas. A reference tool for identification of astronomical sources, A&AS, 143, 33B Πηπρηαθή / Γηπισκαηηθή Δξγαζία 154 Tsagkalidou X., A study of 55 radiosources. Boselli, A., Fossati, M., Gavazzi, G., Ciesla, L., Buat, V., Boissier, S., Hughes, T. M., 2015, Hα imaging of the Herschel Reference Survey.
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    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.
  • Review Article Star Formation Histories of Dwarf Galaxies from the Colour-Magnitude Diagrams of Their Resolved Stellar Populations

    Review Article Star Formation Histories of Dwarf Galaxies from the Colour-Magnitude Diagrams of Their Resolved Stellar Populations

    Hindawi Publishing Corporation Advances in Astronomy Volume 2010, Article ID 158568, 25 pages doi:10.1155/2010/158568 Review Article Star Formation Histories of Dwarf Galaxies from the Colour-Magnitude Diagrams of Their Resolved Stellar Populations Michele Cignoni1, 2 and Monica Tosi2 1 Astronomy Department, Bologna University, Via Ranzani 1, 40127 Bologna, Italy 2 Osservatorio Astronomico di Bologna, INAF, Via Ranzani 1, 40127 Bologna, Italy Correspondence should be addressed to Michele Cignoni, [email protected] Received 5 May 2009; Accepted 12 August 2009 Academic Editor: Ulrich Hopp Copyright © 2010 M. Cignoni and M. Tosi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In this tutorial paper we summarize how the star formation (SF) history of a galactic region can be derived from the colour- magnitude diagram (CMD) of its resolved stars. The procedures to build synthetic CMDs and to exploit them to derive the SF histories (SFHs) are described, as well as the corresponding uncertainties. The SFHs of resolved dwarf galaxies of all morphological types, obtained from the application of the synthetic CMD method, are reviewed and discussed. To summarize: (1) only early-type galaxies show evidence of long interruptions in the SF activity; late-type dwarfs present rather continuous, or gasping, SF regimes; (2) a few early-type dwarfs have experienced only one episode of SF activity concentrated at the earliest epochs, whilst many others show extended or recurrent SF activity; (3) no galaxy experiencing now its first SF episode has been found yet; (4) no frequent evidence of strong SF bursts is found; (5) there is no significant difference in the SFH of dwarf irregulars and blue compact dwarfs, except for the current SF rates.
  • Synapses of Active Galactic Nuclei: Comparing X-Ray and Optical Classifications Using Artificial Neural Networks?

    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.
  • Arxiv:1912.02186V1 [Astro-Ph.GA] 4 Dec 2019 Early in the Formation of an L∗ Galaxy

    Arxiv:1912.02186V1 [Astro-Ph.GA] 4 Dec 2019 Early in the Formation of an L∗ Galaxy

    Draft version December 6, 2019 Typeset using LATEX twocolumn style in AASTeX63 Elemental Abundances in M31: The Kinematics and Chemical Evolution of Dwarf Spheroidal Satellite Galaxies∗ Evan N. Kirby,1 Karoline M. Gilbert,2, 3 Ivanna Escala,1, 4 Jennifer Wojno,3 Puragra Guhathakurta,5 Steven R. Majewski,6 and Rachael L. Beaton4, 7, y 1California Institute of Technology, 1200 E. California Blvd., MC 249-17, Pasadena, CA 91125, USA 2Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218, USA 3Department of Physics & Astronomy, Bloomberg Center for Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 4Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544 5Department of Astronomy & Astrophysics, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA 6Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325, USA 7The Observatories of the Carnegie Institution for Science, 813 Santa Barbara St., Pasadena, CA 91101 (Accepted 3 December 2019) Submitted to AJ ABSTRACT We present deep spectroscopy from Keck/DEIMOS of Andromeda I, III, V, VII, and X, all of which are dwarf spheroidal satellites of M31. The sample includes 256 spectroscopic members across all five dSphs. We confirm previous measurements of the velocity dispersions and dynamical masses, and we provide upper limits on bulk rotation. Our measurements confirm that M31 satellites obey the same relation between stellar mass and stellar metallicity as Milky Way (MW) satellites and other dwarf galaxies in the Local Group. The metallicity distributions show similar trends with stellar mass as MW satellites, including evidence in massive satellites for external influence, like pre-enrichment or gas accretion.