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1984 Statistics
NATIONAL RADIO ASTRONOMY OBSERVATORY Observing Summary - 1984 Statistics February 1985 NATIONAL RADIO ASTRONOMY OBSERVATORY Observing Summary - 1984 Statistics February 1985 Some Highlights of the 1984 Research Program • The 300-foot telescope was used to detect low-frequency carbon recombination lines from cold, diffuse Interstellar clouds in the direction of Cas A. Previously reported absorption lines were confirmed at 26 MHz and a number of other lines were identified in the 25 MHz to 68 MHz range. These lines promise to become an important diagnostic for the ionization conditions in cool interstellar clouds. • Extremely painstaking observations of several Abell clusters of galaxies with the 140-foot telescope have yielded three positive detections of the Sunyaev-Zeldovich effect. The dimunition in the brightness of the microwave background in the direction of clusters is the direct result of the Inverse Compton scattering of the 3° K blackbody photons by electrons in the Intracluster gas. The observations took full advantage of the low noise temperature, broadband, and excellent stability of the Green Bank 18-26 MHz maser system. • The J ■ 1*0 transition of the long-sought-after molecular ion, HCNff*", was detected with the 12-meter telescope at 74.1 GHz. The existence of protonated HCN is one of the prime tests of the theory of ion-molecule reaction schemes in interstellar chemistry. Virtually all CN-containing interstellar molecules, such as HCN, HNC, and many long-chain cyanopolyynes, form directly from HCNH+. • A high-resolution VLA survey of all catalogued, high surface brightness, compact objects in the southern galactic plane uncovered a few objects which are not classifiable into previously known SNR categories. -
Molecular Gas in the Elliptical Galaxy NGC 759 Cessfully Reproduce the Observed Properties (Hernquist & Barnes 1991)
A&A manuscript no. (will be inserted by hand later) ASTRONOMY AND Your thesaurus codes are: ASTROPHYSICS 09.13.2; 11.05.1; 11.09.1; 11.09.4; 11.11.1; 6.8.2018 Molecular gas in the elliptical galaxy NGC 759 Interferometric CO observations T. Wiklind1, F. Combes2, C. Henkel3, F. Wyrowski3,4 1 Onsala Space Observatory, S–43992 Onsala, Sweden 2 DEMIRM Observatoire de Paris, 61 Avenue de l’Observatoire, F–75014 Paris, France 3 Max-Planck-Institut f¨ur Radioastronomie, Auf dem H¨ugel 69, D–53121 Bonn, Germany 4 Physikalisches Institut der Universit¨at zu K¨oln, Z¨ulpicher Strasse 77, D–50937 K¨oln, Germany Received date; Accepted date Abstract. We present interferometric observations of CO(1–0) emission in the elliptical galaxy NGC 759 with an angular resolution of 3 ′′. 1 2 ′′. 3 (990 735pc at a distance × × 9 1. Introduction of 66Mpc). NGC759 contains 2.4 10 M⊙ of molecular × gas. Most of the gas is confined to a small circumnuclear Faber & Gallagher (1976) found the apparent absence of ◦ ring with a radius of 650 pc with an inclination of 40 . The an interstellar medium (ISM) in elliptical galaxies surpris- −2 maximum gas surface density in the ring is 750 M⊙ pc . ing since mass loss from evolved stars should contribute as 9 10 Although this value is very high, it is always less than much as 10 10 M⊙ of gas to the ISM during a Hubble or comparable to the critical gas surface density for large time. Today− we know that ellipticals do contain an ISM, scale gravitational instabilities. -
The Title of My
Research in Astronomy and Astrophysics manuscript no. (LATEX: cgw.tex; printed on January 14, 2020; 2:35) Constraints on individual supermassive binary black holes using observations of PSR J1909 3744 − Yi Feng1,2,3, Di Li1,3, Yan-Rong Li4 and Jian-Min Wang4 1 National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China ; [email protected] 2 University of Chinese Academy of Sciences, Beijing 100049, China 3 CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 4 Institute of High Energy Physics, Chinese Academy of Sciences,19B Yuquan Road, Beijing 100049, China Abstract We perform a search for gravitational waves (GWs) from several supermassive binary black hole (SMBBH) candidates (NGC 5548, Mrk 231, OJ 287, PG 1302-102, NGC 4151, Ark 120 and 3C 66B) in long-term timing observations of the pulsar PSR J1909 3744 − obtained using the Parkes radio telescope. No statistically significant signals were found. We constrain the chirp masses of those SMBBH candidates and find the chirp mass of NGC 5548 and3C66Btobeless than2.4 109 M and 2.5 109 M (with 95% confidence), respectively. × ⊙ × ⊙ Our upperlimits remaina factor of 3 to 370 abovethe likely chirp masses for these candidates as estimated from other approaches. The observations processed here provide upper limits on the GW strain amplitude that improve upon the results from the first Parkes Pulsar Timing arXiv:1907.03460v2 [astro-ph.IM] 13 Jan 2020 Array data release by a factor of 2 to 7. We investigate how information about the orbital pa- rameters can help improve the search sensitivity for individual SMBBH systems. -
The Interstellar and Circumnuclear Medium of Active Nuclei Traced by H I 21 Cm Absorption
The Astronomy and Astrophysics Review (2018) 26:4 https://doi.org/10.1007/s00159-018-0109-x REVIEW ARTICLE The interstellar and circumnuclear medium of active nuclei traced by H i 21 cm absorption Raffaella Morganti1,2 · Tom Oosterloo1,2 Received: 23 April 2018 © The Author(s) 2018 Abstract This review summarises what we have learnt in the last two decades based on H i 21 cm absorption observations about the cold interstellar medium (ISM) in the central regions of active galaxies and about the interplay between this gas and the active nucleus (AGN). Hi absorption is a powerful tracer on all scales, from the parsec-scales close to the central black hole to structures of many tens of kpc tracing interactions and mergers of galaxies. Given the strong radio continuum emission often associated with the central activity, H i absorption observations can be used to study the Hi near an active nucleus out to much higher redshifts than is possible using H i emission. In this way, Hi absorption has been used to characterise in detail the general ISM in active galaxies, to trace the fuelling of radio-loud AGN, to study the feedback occurring between the energy released by the active nucleus and the ISM, and the impact of such interactions on the evolution of galaxies and of their AGN. In the last two decades, significant progress has been made in all these areas. It is now well established that many radio loud AGN are surrounded by small, regularly rotating gas disks that contain a significant fraction of H i. -
The Third Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope M
The Astrophysical Journal, 810:14 (34pp), 2015 September 1 doi:10.1088/0004-637X/810/1/14 © 2015. The American Astronomical Society. All rights reserved. THE THIRD CATALOG OF ACTIVE GALACTIC NUCLEI DETECTED BY THE FERMI LARGE AREA TELESCOPE M. Ackermann1, M. Ajello2, W. B. Atwood3, L. Baldini4, J. Ballet5, G. Barbiellini6,7, D. Bastieri8,9, J. Becerra Gonzalez10,11, R. Bellazzini12, E. Bissaldi13, R. D. Blandford14, E. D. Bloom14, R. Bonino15,16, E. Bottacini14, T. J. Brandt10, J. Bregeon17, R. J. Britto18, P. Bruel19, R. Buehler1, S. Buson8,9, G. A. Caliandro14,20, R. A. Cameron14, M. Caragiulo13, P. A. Caraveo21, B. Carpenter10,22, J. M. Casandjian5, E. Cavazzuti23, C. Cecchi24,25, E. Charles14, A. Chekhtman26, C. C. Cheung27, J. Chiang14, G. Chiaro9, S. Ciprini23,24,28, R. Claus14, J. Cohen-Tanugi17, L. R. Cominsky29, J. Conrad30,31,32,70, S. Cutini23,24,28,R.D’Abrusco33,F.D’Ammando34,35, A. de Angelis36, R. Desiante6,37, S. W. Digel14, L. Di Venere38, P. S. Drell14, C. Favuzzi13,38, S. J. Fegan19, E. C. Ferrara10, J. Finke27, W. B. Focke14, A. Franckowiak14, L. Fuhrmann39, Y. Fukazawa40, A. K. Furniss14, P. Fusco13,38, F. Gargano13, D. Gasparrini23,24,28, N. Giglietto13,38, P. Giommi23, F. Giordano13,38, M. Giroletti34, T. Glanzman14, G. Godfrey14, I. A. Grenier5, J. E. Grove27, S. Guiriec10,2,71, J. W. Hewitt41,42, A. B. Hill14,43,68, D. Horan19, R. Itoh40, G. Jóhannesson44, A. S. Johnson14, W. N. Johnson27, J. Kataoka45,T.Kawano40, F. Krauss46, M. Kuss12, G. La Mura9,47, S. Larsson30,31,48, L. -
The B3-VLA CSS Sample⋆
A&A 528, A110 (2011) Astronomy DOI: 10.1051/0004-6361/201015379 & c ESO 2011 Astrophysics The B3-VLA CSS sample VIII. New optical identifications from the Sloan Digital Sky Survey The ultraviolet-optical spectral energy distribution of the young radio sources C. Fanti1,R.Fanti1, A. Zanichelli1, D. Dallacasa1,2, and C. Stanghellini1 1 Istituto di Radioastronomia – INAF, via Gobetti 101, 40129 Bologna, Italy e-mail: [email protected] 2 Dipartimento di Astronomia, Università di Bologna, via Ranzani 1, 40127 Bologna, Italy Received 12 July 2010 / Accepted 22 December 2010 ABSTRACT Context. Compact steep-spectrum radio sources and giga-hertz peaked spectrum radio sources (CSS/GPS) are generally considered to be mostly young radio sources. In recent years we studied at many wavelengths a sample of these objects selected from the B3-VLA catalog: the B3-VLA CSS sample. Only ≈60% of the sources were optically identified. Aims. We aim to increase the number of optical identifications and study the properties of the host galaxies of young radio sources. Methods. We cross-correlated the CSS B3-VLA sample with the Sloan Digital Sky Survey (SDSS), DR7, and complemented the SDSS photometry with available GALEX (DR 4/5 and 6) and near-IR data from UKIRT and 2MASS. Results. We obtained new identifications and photometric redshifts for eight faint galaxies and for one quasar and two quasar candi- dates. Overall we have 27 galaxies with SDSS photometry in five bands, for which we derived the ultraviolet-optical spectral energy distribution (UV-O-SED). We extended our investigation to additional CSS/GPS selected from the literature. -
October 2006
OCTOBER 2 0 0 6 �������������� http://www.universetoday.com �������������� TAMMY PLOTNER WITH JEFF BARBOUR 283 SUNDAY, OCTOBER 1 In 1897, the world’s largest refractor (40”) debuted at the University of Chica- go’s Yerkes Observatory. Also today in 1958, NASA was established by an act of Congress. More? In 1962, the 300-foot radio telescope of the National Ra- dio Astronomy Observatory (NRAO) went live at Green Bank, West Virginia. It held place as the world’s second largest radio scope until it collapsed in 1988. Tonight let’s visit with an old lunar favorite. Easily seen in binoculars, the hexagonal walled plain of Albategnius ap- pears near the terminator about one-third the way north of the south limb. Look north of Albategnius for even larger and more ancient Hipparchus giving an almost “figure 8” view in binoculars. Between Hipparchus and Albategnius to the east are mid-sized craters Halley and Hind. Note the curious ALBATEGNIUS AND HIPPARCHUS ON THE relationship between impact crater Klein on Albategnius’ southwestern wall and TERMINATOR CREDIT: ROGER WARNER that of crater Horrocks on the northeastern wall of Hipparchus. Now let’s power up and “crater hop”... Just northwest of Hipparchus’ wall are the beginnings of the Sinus Medii area. Look for the deep imprint of Seeliger - named for a Dutch astronomer. Due north of Hipparchus is Rhaeticus, and here’s where things really get interesting. If the terminator has progressed far enough, you might spot tiny Blagg and Bruce to its west, the rough location of the Surveyor 4 and Surveyor 6 landing area. -
Counting Gamma Rays in the Directions of Galaxy Clusters
A&A 567, A93 (2014) Astronomy DOI: 10.1051/0004-6361/201322454 & c ESO 2014 Astrophysics Counting gamma rays in the directions of galaxy clusters D. A. Prokhorov1 and E. M. Churazov1,2 1 Max Planck Institute for Astrophysics, Karl-Schwarzschild-Strasse 1, 85741 Garching, Germany e-mail: [email protected] 2 Space Research Institute (IKI), Profsouznaya 84/32, 117997 Moscow, Russia Received 6 August 2013 / Accepted 19 May 2014 ABSTRACT Emission from active galactic nuclei (AGNs) and from neutral pion decay are the two most natural mechanisms that could establish a galaxy cluster as a source of gamma rays in the GeV regime. We revisit this problem by using 52.5 months of Fermi-LAT data above 10 GeV and stacking 55 clusters from the HIFLUCGS sample of the X-ray brightest clusters. The choice of >10 GeV photons is optimal from the point of view of angular resolution, while the sample selection optimizes the chances of detecting signatures of neutral pion decay, arising from hadronic interactions of relativistic protons with an intracluster medium, which scale with the X-ray flux. In the stacked data we detected a signal for the central 0.25 deg circle at the level of 4.3σ. Evidence for a spatial extent of the signal is marginal. A subsample of cool-core clusters has a higher count rate of 1.9 ± 0.3 per cluster compared to the subsample of non-cool core clusters at 1.3 ± 0.2. Several independent arguments suggest that the contribution of AGNs to the observed signal is substantial, if not dominant. -
198 8Apj. . .329. .532K the Astrophysical Journal, 329:532-550
.532K The Astrophysical Journal, 329:532-550,1988 June 15 © 1988. The American Astronomical Society. All rights reserved. Printed in U.S.A. .329. 8ApJ. 198 THE OPTICAL CONTINUA OF EXTRAGALACTIC RADIO JETS1 William C. Keel Sterrewacht Leiden Received 1987 August 11 ; accepted 1987 December 11 ABSTRACT Multicolor optical images have been used to measure the broad-band spectral shapes of radio jets known to show optical counterparts, and to search for such counterparts in additional objects. One new detection, the brightest knot in the NGC 6251 jet, is reported. In all cases, except part of the 3C 273 jet, the jet continua are well-represented by synchrotron spectra from truncated power-law electron distributions, with emitted-frame critical frequencies between 3 x 1014 and 2 x 1015 Hz. This may be due to fine structure in the jets or to the particle (re)acceleration process. Two hot spots (Pic A and 3C 303) differ from the jets, in showing unbroken power-law spectra from the radio to the B band. Image restoration has been used to examine the sub-arcsecond structure of the M87 jet and derive spectral shapes for various knots free of blending problems. The structure matches that seen in the radio to the Ol'S level, implying that the jet structure prevents particles from streaming freely over this distance (~30pc) Significant changes in turnover frequency occur from knot to knot, with an overall trend of higher frequency closer to the nucleus. Knot A is an exception, with a spectrum like the features near the core. An Appendix gives results of surface photometry for the program galaxies. -
Lemmings. I. the Emerlin Legacy Survey of Nearby Galaxies. 1.5-Ghz Parsec-Scale Radio Structures and Cores
MNRAS 000,1{44 (2018) Preprint 8 February 2018 Compiled using MNRAS LATEX style file v3.0 LeMMINGs. I. The eMERLIN legacy survey of nearby galaxies. 1.5-GHz parsec-scale radio structures and cores R. D. Baldi1?, D. R. A. Williams1, I. M. McHardy1, R. J. Beswick2, M. K. Argo2;3, B. T. Dullo4, J. H. Knapen5;6, E. Brinks7, T. W. B. Muxlow2, S. Aalto8, A. Alberdi9, G. J. Bendo2;10, S. Corbel11;12, R. Evans13, D. M. Fenech14, D. A. Green15, H.-R. Kl¨ockner16, E. K¨ording17, P. Kharb18, T. J. Maccarone19, I. Mart´ı-Vidal8, C. G. Mundell20, F. Panessa21, A. B. Peck22, M. A. P´erez-Torres9, D. J. Saikia18, P. Saikia17;23, F. Shankar1, R. E. Spencer2, I. R. Stevens24, P. Uttley25 and J. Westcott7 1 School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ, UK 2 Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK 3 Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE, UK 4 Departamento de Astrofisica y Ciencias de la Atmosfera, Universidad Complutense de Madrid, E-28040 Madrid, Spain 5 Instituto de Astrofisica de Canarias, Via Lactea S/N, E-38205, La Laguna, Tenerife, Spain 6 Departamento de Astrofisica, Universidad de La Laguna, E-38206, La Laguna, Tenerife, Spain 7 Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield, AL10 9AB, UK 8 Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, 43992 Onsala, Sweden 9 Instituto de Astrofisica de Andaluc´ıa(IAA, CSIC); Glorieta de la Astronom´ıa s/n, 18008-Granada, Spain 10 ALMA Regional Centre Node, UK 11 Laboratoire AIM (CEA/IRFU - CNRS/INSU - Universit´eParis Diderot), CEA DSM/IRFU/SAp, F-91191 Gif-sur-Yvette, France 12 Station de Radioastronomie de Nan¸cay, Observatoire de Paris, PSL Research University, CNRS, Univ. -
Cfa in the News ~ Week Ending 3 January 2010
Wolbach Library: CfA in the News ~ Week ending 3 January 2010 1. New social science research from G. Sonnert and co-researchers described, Science Letter, p40, Tuesday, January 5, 2010 2. 2009 in science and medicine, ROGER SCHLUETER, Belleville News Democrat (IL), Sunday, January 3, 2010 3. 'Science, celestial bodies have always inspired humankind', Staff Correspondent, Hindu (India), Tuesday, December 29, 2009 4. Why is Carpenter defending scientists?, The Morning Call, Morning Call (Allentown, PA), FIRST ed, pA25, Sunday, December 27, 2009 5. CORRECTIONS, OPINION BY RYAN FINLEY, ARIZONA DAILY STAR, Arizona Daily Star (AZ), FINAL ed, pA2, Saturday, December 19, 2009 6. We see a 'Super-Earth', TOM BEAL; TOM BEAL, ARIZONA DAILY STAR, Arizona Daily Star, (AZ), FINAL ed, pA1, Thursday, December 17, 2009 Record - 1 DIALOG(R) New social science research from G. Sonnert and co-researchers described, Science Letter, p40, Tuesday, January 5, 2010 TEXT: "In this paper we report on testing the 'rolen model' and 'opportunity-structure' hypotheses about the parents whom scientists mentioned as career influencers. According to the role-model hypothesis, the gender match between scientist and influencer is paramount (for example, women scientists would disproportionately often mention their mothers as career influencers)," scientists writing in the journal Social Studies of Science report (see also ). "According to the opportunity-structure hypothesis, the parent's educational level predicts his/her probability of being mentioned as a career influencer (that ism parents with higher educational levels would be more likely to be named). The examination of a sample of American scientists who had received prestigious postdoctoral fellowships resulted in rejecting the role-model hypothesis and corroborating the opportunity-structure hypothesis. -
A Search for Transiting Extrasolar Planets in the Open Cluster NGC 4755
ResearchOnline@JCU This file is part of the following reference: Jayawardene, Bandupriya S. (2015) A search for transiting extrasolar planets in the open cluster NGC 4755. DAstron thesis, James Cook University. Access to this file is available from: http://researchonline.jcu.edu.au/41511/ The author has certified to JCU that they have made a reasonable effort to gain permission and acknowledge the owner of any third party copyright material included in this document. If you believe that this is not the case, please contact [email protected] and quote http://researchonline.jcu.edu.au/41511/ A SEARCH FOR TRANSITING EXTRASOLAR PLANETS IN THE OPEN CLUSTER NGC 4755 by Bandupriya S. Jayawardene A thesis submitted in satisfaction of the requirements for the degree of Doctor of Astronomy in the Faculty of Science, Technology and Engineering June 2015 James Cook University Townsville - Australia i STATEMENT OF ACCESS I the undersigned, author of this work, understand that James Cook University will make this thesis available for use within the University Library and, via the Australian Digital Thesis network, for use elsewhere. I understand that, as an unpublished work, a thesis has significant protection under the Copyright Act and; I do not wish to place any further restriction on access to this work. 2 STATEMENT OF SOURCES DECLARATION I declare that this thesis is my own work and has not been submitted in any form for another degree or diploma at any University or other institution of tertiary education. Information derived from the published or unpublished work of others has been acknowledged in the text and list of references is given.