The Journal of the Royal Astronomical Society of New Zealand

Total Page:16

File Type:pdf, Size:1020Kb

The Journal of the Royal Astronomical Society of New Zealand Southern Stars THE JOURNAL OF THE ROYAL ASTRONOMICAL SOCIETY OF NEW ZEALAND Volume 58, No 2 2019 June ISSN Page0049-1640 1 Southern Stars Journal of the RASNZ Royal Astronomical Society Volume 58, Number 2 of New Zealand (Inc.) 2019 June Founded in 1920 as the New Zealand Astronomical Society and assumed its present title on receiving the Royal Charter in 1946. In 1967 it became a member body of the R oyal Society of New Zealand. CONTENTS P O Box 3181, Wellington 6140, New Zealand SWAPA Students Captivated by the Stars at the 2019 [email protected] http://www.rasnz.org.nz RASNZ Conference in New Plymouth John Drummond ...................................................... 3 Subscriptions (NZ$) for 2019: Ordinary member: $40.00 Student member: $20.00 The Morphology of Galaxies Aayushi Verma ........................................................ 7 Affiliated society: $3.75 per member. Minimum $75.00, Maximum $375.00 Corporate member: $200.00 Antony Gomez Chris Monigatti, Duncan Hall .................................. 11 Printed copies of Southern Stars (NZ$): $35.00 (NZ) AR12738: ‘Salvoes of Surges’ Harry Roberts ........................................................ 12 $45.00 (Australia & South Pacific) $50.00 (Rest of World) AR12738 Returns: Surging Renewed! Harry Roberts ........................................................ 13 Council & Officers 2018 to 2020 Exoplanet Research: News on the NUS_NZ President: Collaboration Nicholas Rattenbury Department of Physics, Timothy Banks & Edwin Budding .......................... 14 The University of Auckland, Private Bag 92019, Auckland 1142. [email protected] Grus and the Grus Galaxy Chain Andrew Robertson ................................................ 17 Immediate Past President: John Drummond P O Box 113, Patutahi 4045. [email protected] Adaptive Tracking Craig Young ........................................................... 20 Vice President: Steve Butler 30 Hoffman Court, Invercargill 9810. [email protected] John Drummond, FRASNZ Nalayini Davies ..................................................... 26 Secretary: Appointment pending. [email protected] Treasurer: Susan Shoebridge Apt 101/367 Great North Road, Grey Lynn, Auckland 1021. [email protected] Members’ Councillors: Hinerangi Curtis 96B Hinau St, Riccarton, Christchurch 8041. [email protected] FRONT COVER Craig Young standing beside his 16” Photometric Bob Evans 15 Taiepa Rd, Otatara RD9, Invercargill 9879. [email protected] telescope inside his Crystal Lake Observatory in the Waikato, New Zealand. John Hearnshaw 39 Kirkwood Ave, Christchurch 8041. [email protected] [email protected] BACK COVER Glen Rowe 23 Stanhope Grove, Korokoro, Lower Hutt 5012. The 2019 SWAPA Students. [email protected] Affiliated Societies’ Councillors: Nalayini Davies 9 Castle Drive, Epsom, Auckland 1023. [email protected] Peter Jaquiery 31 Wright St, Dunedin 9010. [email protected] Fellows’ Councillor: Karen Pollard School of Physical and Chemical Sciences, University of Canterbury, Page 2 Private Bag 4800, Christchurch 8140. Southern Stars [email protected] SWAPA Students Captivated by the Stars at the 2019 RASNZ Conference in New Plymouth:- John Drummond SWAPA Students Captivated by the Stars at the 2019 RASNZ Conference in New Plymouth John Drummond Students With A Passion for Astronomy The fifth SWAPA scheme at the recent RASNZ conference in New Plymouth was another resounding success. The SWAPA (Students With A Passion for Astronomy) scheme, binoculars and other goodies that RASNZ sponsor, ASTRONZ, instigated by Professor John Hearnshaw, invites senior high had at the conference. An additional blessing of the SWAPA school students from around Aotearoa to submit a 300-word scheme was that SWAPA winners from previous years were essay stating how they have a passion for astronomy and also at the conference – sometimes in roles of responsibility. why they should be chosen to attend the RASNZ conference free of charge. I sent out email invitations to nearly 500 high Here’s some statements made by the SWAPA students after the schools and received 88 excellent entries. Of these, ten were conference… chosen by Professor John Hearnshaw and me as winners. These ten SWAPA winners won free conference registration, Breanna Camden free entry to the Saturday night banquet, free travel to/from The 2019 RASNZ conference in New the conference and their accommodation was paid for. This Plymouth, as part of the SWAPA due to the very generous donation of Michael Snowden last scheme, was an amazing opportunity year. In addition, the ten SWAPA students received a one-year which I am so thankful to have membership subscription to the Royal Astronomical Society of attended. It allowed me to connect with New Zealand. like-minded students who are going on to study similar areas of astronomy On the Saturday morning, before proceedings, the students met and astrophysics, and I hope to have with two professional astronomers – Professor Karen Pollard created many lasting contacts. I was (University of Canterbury) and Dr Nic Rattenbury (Auckland also lucky enough to meet a remarkable University) - to talk about possible careers in astronomy, group of university students who are a physics, etc. The questions asked by the students during this part of the New Zealand Students Space breakfast were excellent. In addition, the students met with Association, a student-led initiative whose aim is to get more the conference keynote speaker, Professor Lisa Kewley, for students of all ages involved in astronomy and space sciences. an hour while the RASNZ AGM was in progress on Saturday Meeting members of the scientific community in the fields of afternoon. astronomy and astrophysics was a wonderful experience and I was blown away by the passion which was present. Talking The students presented excellent short talks at the conference to these people allowed me to discover more about what it is about themselves, what got them into astronomy, how they are like to have a career in astronomy, and I was inspired by each actively involved in it and what they might do, study-wise, at and every person I met. Furthermore, I enjoyed listening to university. It was very pleasing to see the students meeting presentations on such a wide range of subjects, something with and discussing astronomy with professional and amateur which opened my eyes to some of the variety of amazing areas astronomers. The enthusiasm and maturity shown by them of research going on in this field, from asteroidal occultations was meritorious. They were also drooling over telescopes, and microlensing, to the evolution of galaxies and the universe. I particularly enjoyed listening SWAPA WINNERS - 2019 to the talk on 3-dimensional Name Age Yr School City spectroscopy given by the invited Breanna Camden 16 13 New Plymouth Girls’ High New Plymouth speaker Professor Lisa Kewley, a truly inspiring woman who we Bryn Thompson 17 13 Awatapu College Palmerston North were given the opportunity to Heather Sinclair - Wentworth 17 13 Motueka High School Motueka speak with, ask questions about Jack McCorkindale 17 13 Wakatipu High School Queenstown her career and receive advice and Joseph Chamberlain 17 13 Freyberg High School Palmerston North wisdom which I am sure we all appreciated. Leah Albrow 17 13 Riccarton High School Christchurch Natalie Bennett 17 13 Napier Girls’ High School Napier Opportunities such as these Niamh Stratton 17 13 Campion College Gisborne are of great importance for Sarah Poulter 17 13 St Mary’s College Auckland prospective science students, for they allow young people such as Vivek Panchal 16 13 Howick College Auckland myself to experience and become 58, 2, 2019 June Page 3 SWAPA Students Captivated by the Stars at the 2019 RASNZ Conference in New Plymouth:- John Drummond immersed in a range of potential careers, many which we may course still enjoyable. It was great have not been aware of. Astronomy in particular is a subject to meet fellow Astronomy nerds not commonly taught at secondary schools, making this an like myself, old and young, and to awesome opportunity where I was able to learn so much about catch up with those students I had this science. Speaking at the conference about my passion for met before. Having the opportunity astronomy and where I hoped it would take me in the future to talk about my small Astronomy was something I found so beneficial, as not only did it improve journey so far was an amazing my confidence in speaking in front of others, but it gave me a experience with the audience being sense of empowerment that as a young person I am capable of very supportive and interested “putting myself out there” in the astronomical community. I in hearing from all of us, how was gratified and pleasantly surprised when following my talk, Astronomy fitted into our lives. I was approached by some of the conference attendees who Meeting the newly formed NZSSA (New Zealand Student were interested to learn more about where and what I hoped Space Association) was inspiring as even though I plan to to study, or who wanted to share with me some fascinating study Astronomy, it was good to see that as a student there is cosmological theories and astronomical discoveries. a group I can be a part of to get more involved in Astronomy. One talk I particularly enjoyed was from one of the University Attending the conference has fuelled my passion for astronomy, of Canterbury students, Aayushi Verma, about her research
Recommended publications
  • The Local Radio-Galaxy Population at 20
    Mon. Not. R. Astron. Soc. 000, 1–?? (2013) Printed 2 December 2013 (MN LATEX style file v2.2) The local radio-galaxy population at 20GHz Elaine M. Sadler1⋆, Ronald D. Ekers2, Elizabeth K. Mahony3, Tom Mauch4,5, Tara Murphy1,6 1Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006, Australia 2Australia Telescope National Facility, CSIRO, PO Box 76, Epping, NSW 1710, Australia 3ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA, Dwingeloo, The Netherlands 4Oxford Astrophysics, Department of Physics, Keble Road, Oxford OX1 3RH 5SKA Africa, 3rd Floor, The Park, Park Road, Pinelands, 7405, South Africa 6School of Information Technologies, The University of Sydney, NSW 2006, Australia Accepted 0000 December 08. Received 0000 December 08; in original form 0000 December 08 ABSTRACT We have made the first detailed study of the high-frequency radio-source population in the local universe, using a sample of 202 radio sources from the Australia Telescope 20GHz (AT20G) survey identified with galaxies from the 6dF Galaxy Survey (6dFGS). The AT20G- 6dFGS galaxies have a median redshift of z=0.058 and span a wide range in radio luminosity, allowing us to make the first measurement of the local radio luminosity function at 20GHz. Our sample includes some classical FR-1 and FR-2 radio galaxies, but most of the AT20G-6dFGS galaxies host compact (FR-0) radio AGN which appear lack extended radio emission even at lower frequencies. Most of these FR-0 sources show no evidence for rela- tivistic beaming, and the FR-0 class appears to be a mixed population which includes young Compact Steep-Spectrum (CSS) and Gigahertz-Peaked Spectrum (GPS) radio galaxies.
    [Show full text]
  • The Origin of the Iron Lines in NGC 7213
    A&A 407, L21–L24 (2003) Astronomy DOI: 10.1051/0004-6361:20031054 & c ESO 2003 Astrophysics The origin of the iron lines in NGC 7213 S. Bianchi, G. Matt, I. Balestra, and G. C. Perola Dipartimento di Fisica, Universit`a degli Studi Roma Tre, Italy Received 20 June 2003 / Accepted 8 July 2003 Letter to the Editor Abstract. The analysis of a simultaneous XMM-Newton/BeppoSAX plus three previous BeppoSAX observations revealed that NGC 7213 is a rather peculiar Seyfert 1. No significant Compton reflection component was observed, while an iron line complex, best explained in terms of three narrow lines, is clearly apparent in the data. Due to the absence of the reflection component, the neutral iron line is likely not produced in a Compton-thick material, but current data do not allow to choose between a Compton-thin torus and the BLR. The two ionized iron lines from Fe xxv and Fe xxvi may be produced in a 23 2 photoionized gas with a column density of a few 10 cm− , in analogy with the case of NGC 5506. Key words. galaxies: individual: NGC 7213 – galaxies: Seyfert – X-rays: galaxies 1. Introduction the BeppoSAX PDS instrument. On the other hand, if the line is produced in the BLR, a much fainter Compton reflection Iron Kα emission lines are common features in Seyfert 1s. The component is expected, and the intrinsic width of the iron line profile of the line provides fundamental information on their should be the same as that of the optical broad lines. origin. If it is produced in the innermost regions of the accre- The nuclear activity of NGC 7213 (z = 0:005977) was tion disk, kinematic and relativistic effects contribute to forge discovered by the HEAO A-2 satellite (Marshall et al.
    [Show full text]
  • University of Southampton Research Repository Eprints Soton
    University of Southampton Research Repository ePrints Soton Copyright © and Moral Rights for this thesis are retained by the author and/or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder/s. The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders. When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given e.g. AUTHOR (year of submission) "Full thesis title", University of Southampton, name of the University School or Department, PhD Thesis, pagination http://eprints.soton.ac.uk UNIVERSITY OF SOUTHAMPTON FACULTY OF PHYSICAL SCIENCES AND ENGINEERING Physics And Astronomy Fast Spectral Variability in the X-ray Emission of Accreting Black Holes by Chris J. Skipper Thesis for the degree of Doctor of Philosophy October 2013 UNIVERSITY OF SOUTHAMPTON ABSTRACT FACULTY OF PHYSICAL SCIENCES AND ENGINEERING Physics And Astronomy Doctor of Philosophy FAST SPECTRAL VARIABILITY IN THE X-RAY EMISSION OF ACCRETING BLACK HOLES by Chris J. Skipper The X-ray emission from accreting black holes provides the perfect probe for testing the geometry, behaviour and conditions present in the innermost regions of the accretion flow. In this thesis I use X-ray spectral analysis to investigate the properties of accret- ing black holes that extend over several orders of magnitude in accretion rate (m˙ E) and black hole mass (MBH), from the stellar mass black holes in X-ray binary systems (XRBs) to the supermassive black holes in active galactic nuclei (AGN).
    [Show full text]
  • Lopsided Spiral Galaxies: Evidence for Gas Accretion
    A&A 438, 507–520 (2005) Astronomy DOI: 10.1051/0004-6361:20052631 & c ESO 2005 Astrophysics Lopsided spiral galaxies: evidence for gas accretion F. Bournaud1, F. Combes1,C.J.Jog2, and I. Puerari3 1 Observatoire de Paris, LERMA, 61 Av. de l’Observatoire, 75014 Paris, France e-mail: [email protected] 2 Department of Physics, Indian Institute of Science, Bangalore 560012, India 3 Instituto Nacional de Astrofísica, Optica y Electrónica, Calle Luis Enrique Erro 1, 72840 Tonantzintla, Puebla, Mexico Received 3 January 2005 / Accepted 15 March 2005 Abstract. We quantify the degree of lopsidedness for a sample of 149 galaxies observed in the near-infrared from the OSUBGS sample, and try to explain the physical origin of the observed disk lopsidedness. We confirm previous studies, but for a larger sample, that a large fraction of galaxies have significant lopsidedness in their stellar disks, measured as the Fourier amplitude of the m = 1 component normalised to the average or m = 0 component in the surface density. Late-type galaxies are found to be more lopsided, while the presence of m = 2 spiral arms and bars is correlated with disk lopsidedness. We also show that the m = 1 amplitude is uncorrelated with the presence of companions. Numerical simulations were carried out to study the generation of m = 1viadifferent processes: galaxy tidal encounters, galaxy mergers, and external gas accretion with subsequent star formation. These simulations show that galaxy interactions and mergers can trigger strong lopsidedness, but do not explain several independent statistical properties of observed galaxies. To explain all the observational results, it is required that a large fraction of lopsidedness results from cosmological accretion of gas on galactic disks, which can create strongly lopsided disks when this accretion is asymmetrical enough.
    [Show full text]
  • Probing the Physics of Narrow Line Regions in Active Galaxies II: the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7)
    Probing the Physics of Narrow Line Regions in Active Galaxies II: The Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) Michael A. Dopita1,2, Prajval Shastri3, Rebecca Davies1, Lisa Kewley1,4, Elise Hampton1, Julia Scharw¨achter5, Ralph Sutherland1, Preeti Kharb3, Jessy Jose3, Harish Bhatt3, S. Ramya 3, Chichuan Jin6, Julie Banfield7, Ingyin Zaw8, St´ephanie Juneau9, Bethan James10 & Shweta Srivastava11 [email protected] ABSTRACT Here we describe the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) and present results on 64 galaxies drawn from the first data release. The S7 uses the Wide Field Spectrograph (WiFeS) mounted on the ANU 2.3m telescope located at the Siding Spring Observatory to deliver an integral field of 38×25 arcsec at a spectral resolution of R = 7000 in the red (530−710nm), and R = 3000 in the blue (340 − 560nm). From these data cubes we have extracted the Narrow Line Region (NLR) spectra from a 4 arc sec aperture centred on the nucleus. We also determine the Hβ and [O III] λ5007 fluxes in the narrow lines, the nuclear reddening, the reddening-corrected relative intensities of the observed emission lines, and the Hβ and [O III] λ5007 luminosities determined 1RSAA, Australian National University, Cotter Road, Weston Creek, ACT 2611, Australia 2Astronomy Department, King Abdulaziz University, P.O. Box 80203, Jeddah, Saudi Arabia 3Indian Institute of Astrophysics, Koramangala 2B Block, Bangalore 560034, India 4Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI, USA 5LERMA, Observatoire de Paris, CNRS, UMR 8112, 61 Avenue de l’Observatoire, 75014, Paris, France 6Qian Xuesen Laboratory for Space Technology, Beijing, China 7CSIRO Astronomy & Space Science, P.O.
    [Show full text]
  • PDF (Accepted Manuscript)
    Swinburne Research Bank http://researchbank.swinburne.edu.au Kilborn, V. A., Forbes, D. A., Barnes, D. G., et al. (2009). Southern GEMS groups II: HI distribution, mass functions and HI deficient galaxies. Originally published in Monthly Notices of the Royal Astronomical Society, 400(4): 1962–1985. Available from: http://dx.doi.org/10.1111/j.1365-2966.2009.15587.x. This version of the article copyright © 2009 The Authors. This is the author’s version of the work. It is posted here with the permission of the publisher for your personal use. No further distribution is permitted. If your library has a subscription to this journal, you may also be able to access the published version via the library catalogue. The definitive version is available at www.interscience.wiley.com. Accessed from Swinburne Research Bank: http://hdl.handle.net/1959.3/71244 Mon. Not. R. Astron. Soc. 000, 1–15 (2005) Printed 3 September 2009 (MN LATEX style file v2.2) Southern GEMS groups II: HI distribution, mass functions and HI deficient galaxies⋆ Virginia A. Kilborn1,2†, Duncan A. Forbes1, David G. Barnes1,3, B¨arbel S. Koribalski2, Sarah Brough1, and Katie Kern1,2 1Centre for Astrophysics & Supercomputing, Swinburne University of Technology, Mail H39, PO Box 218, Hawthorn, VIC 3122, Australia 2Australia Telescope National Facility, CSIRO, P.O. Box 76, Epping, NSW 1710, Australia 3School of Physics, University of Melbourne, Parkville, VIC 3010, Australia ABSTRACT We investigate the neutral hydrogen (H i) content of sixteen groups for which we have multi-wavelength data including X-ray observations. Wide-field imaging of the groups was obtained with the 20-cm multibeam system on the 64-m Parkes telescope.
    [Show full text]
  • Atlante Grafico Delle Galassie
    ASTRONOMIA Il mondo delle galassie, da Kant a skylive.it. LA RIVISTA DELL’UNIONE ASTROFILI ITALIANI Questo è un numero speciale. Viene qui presentato, in edizione ampliata, quan- [email protected] to fu pubblicato per opera degli Autori nove anni fa, ma in modo frammentario n. 1 gennaio - febbraio 2007 e comunque oggigiorno di assai difficile reperimento. Praticamente tutte le galassie fino alla 13ª magnitudine trovano posto in questo atlante di più di Proprietà ed editore Unione Astrofili Italiani 1400 oggetti. La lettura dell’Atlante delle Galassie deve essere fatto nella sua Direttore responsabile prospettiva storica. Nella lunga introduzione del Prof. Vincenzo Croce il testo Franco Foresta Martin Comitato di redazione e le fotografie rimandano a 200 anni di studio e di osservazione del mondo Consiglio Direttivo UAI delle galassie. In queste pagine si ripercorre il lungo e paziente cammino ini- Coordinatore Editoriale ziato con i modelli di Herschel fino ad arrivare a quelli di Shapley della Via Giorgio Bianciardi Lattea, con l’apertura al mondo multiforme delle altre galassie, iconografate Impaginazione e stampa dai disegni di Lassell fino ad arrivare alle fotografie ottenute dai colossi della Impaginazione Grafica SMAA srl - Stampa Tipolitografia Editoria DBS s.n.c., 32030 metà del ‘900, Mount Wilson e Palomar. Vecchie fotografie in bianco e nero Rasai di Seren del Grappa (BL) che permettono al lettore di ripercorrere l’alba della conoscenza di questo Servizio arretrati primo abbozzo di un Universo sempre più sconfinato e composito. Al mondo Una copia Euro 5.00 professionale si associò quanto prima il mondo amatoriale. Chi non è troppo Almanacco Euro 8.00 giovane ricorderà le immagini ottenute dal cielo sopra Bologna da Sassi, Vac- Versare l’importo come spiegato qui sotto specificando la causale.
    [Show full text]
  • Radio Emission of the Nuclei of Barred Spiral Galaxies
    RADIO EMISSION OF THE NUCLEI OF BARRED SPIRAL GALAXIES By H. M. TOVMASSIAN* [Manuscript received May 27, 1966] Summary The results of radio observations of 98 barred galaxies at 11, 21, and 75 cm are presented. The observations were carried out with the 210 ft radio telescope of the Australian National Radio Astronomy Observatory and with the Mills Oross of the Sydney University Molonglo Radio Observatory. Radio emission originating within 1· 5 minutes of arc of the centre of corresponding galaxies was detected in 21 cases. It is concluded that the central parts of galaxies (possibly their nuclei) are responsible for the radio emission. Spectral indices of detected sources were determined. Radio indices show that radio emissivity of the majority of the investi­ gated galaxies is higher than that of normal galaxies. I. INTRODUCTION For some years after the discovery of radio galaxies, collisions between galaxies were accepted by many as the cause of the intense radio emission (Baade and Minkowski 1954; Shklowski 1954; and others). Ambartsumian (1956a) was the first to reject the idea of random collisions as an explanation of the observed phenomena. He came to this conclusion by considering certain observational data, particularly that a collision is an extremely rare event among the superluminous galaxies to which the radio galaxies belong. Subsequently he proposed and developed (Ambartsumian 1956b, 1958, 1962) a theory stressing the importance of the activity of the nuclei in the formation and evolution of galaxies. Some forms of nuclear activ­ ity result in powerful radio emission. Nowadays the hypothesis of nuclear activity is widely accepted and there is much observational evidence in favour of it.
    [Show full text]
  • Cold Molecular Gas and PAH Emission in the Nuclear and Circumnuclear Regions of Seyfert Galaxies.', Astronomy Astrophysics., 639
    Durham Research Online Deposited in DRO: 06 August 2020 Version of attached le: Published Version Peer-review status of attached le: Peer-reviewed Citation for published item: Alonso-Herrero, A. and Pereira-Santaella, M. and Rigopoulou, D. and Garc¡a-Bernete,I. and Garc¡a-Burillo, S. and Dom¡nguez-Fern¡andez,A. J. and Combes, F. and Davies, R. I. and D¡az-Santos, T. and Esparza-Arredondo, D. and Gonz¡alez-Mart¡n,O. and Hern¡an-Caballero, A. and Hicks, E. K. S. and H¤onig,S. F. and Levenson, N. A. and Ramos Almeida, C. and Roche, P. F. and Rosario, D. (2020) 'Cold molecular gas and PAH emission in the nuclear and circumnuclear regions of Seyfert galaxies.', Astronomy astrophysics., 639 . A43. Further information on publisher's website: https://doi.org/10.1051/0004-6361/202037642 Publisher's copyright statement: Alonso-Herrero, A., Pereira-Santaella, M., Rigopoulou, D., Garc¡a-Bernete,I., Garc¡a-Burillo,S., Dom¡nguez-Fern¡andez,A. J., Combes, F., Davies, R. I., D¡az-Santos, T., Esparza-Arredondo, D., Gonz¡alez-Mart¡n, O., Hern¡an-Caballero,A., Hicks, E. K. S., H¤onig,S. F., Levenson, N. A., Ramos Almeida, C., Roche, P. F. Rosario, D. (2020). Cold molecular gas and PAH emission in the nuclear and circumnuclear regions of Seyfert galaxies. Astronomy Astrophysics 639: A43, reproduced with permission, c ESO. 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.
    [Show full text]
  • H-Alpha Imaging of Early-Type (Sa-Sab) Spiral Galaxies I
    Hα Imaging of Early-Type(Sa-Sab) Spiral Galaxies I1 Salman Hameed2, Nick Devereux2 Astronomy Department, New Mexico State University, Las Cruces, NM 88003 ABSTRACT Hα and continuum images are presented for 27 nearby early-type(Sa-Sab) spiral galaxies. Contrary to popular perception, the images reveal copious massive star formation in some of these galaxies. A determination of the Hα morphology and a measure of the Hα luminosity suggests that early-type spirals can be classified into two broad categories based on the luminosity of largest H II region in the disk. The first category includes galaxies for which the 39 −1 individual H II regions have LHα < 10 ergs . Most of the category 1 galaxies appear to be morphologically undisturbed, but show a wide diversity in nuclear Hα properties. The second category includes galaxies which have at least one 39 −1 H II region in the disk with LHα ≥ 10 ergs . All category 2 galaxies show either prominent dust lanes or other morphological peculiarities such as tidal tails which suggests that the anomalously luminous H II regions in category 2 galaxies may have formed as a result of a recent interaction. The observations, which are part of an on-going Hα survey, reveal early-type spirals to be a heterogeneous class of galaxies that are evolving in the current epoch. We have also identified some systematic differences between the classifications of spiral galaxies in the Second General Catalog (RC2) and the Revised Shapley- Ames Catalog (RSA) which may be traced to subtle variations in the application of the criteria used for classifying spiral galaxies.
    [Show full text]
  • Observer's Guide to Galaxies
    Observer’s Guide to Galaxies By Rob Horvat (WSAAG) Mar 2020 This document has evolved from a supplement to Night-Sky Objects for Southern Observers (Night-Sky Objects for short), which became available on the web in 2009. The document has now been split into two, this one being called the Observer’s Guide to Galaxies. The maps have been designed for those interested in locating galaxies by star-hopping around the constellations. However, like Night-Sky Objects, the resource can be used to simply identify interesting galaxies to GOTO. As with Night-Sky Objects, the maps have been designed and oriented for southern observers with the limit of observation being Declination +55 degrees. Facing north, the constellations are inverted so that they are the “right way up”. Facing south, constellations have the usual map orientation. Pages are A4 in size and can be read as a pdf on a computer or tablet. Note on copyright. This document may be freely reproduced without alteration for educational or personal use. Contributed images by WSAAG members remain the property of their authors. Types of Galaxies Spiral (S) galaxies consist of a rotating disk of stars, dust and gas that surround a central bulge or concentration of stars. Bulges often house a central supermassive black hole. Most spiral galaxies have two arms that are sites of ongoing star formation. Arms are brighter than the rest of the disk because of young hot OB class stars. Approx. 2/3 of spiral galaxies have a central bar (SB galaxies). Lenticular (S0) galaxies have a rather formless disk (no obvious spiral arms) with a prominent bulge.
    [Show full text]
  • Books About the Southern Sky
    Books about the Southern Sky Atlas of the Southern Night Sky, Steve Massey and Steve Quirk, 2010, second edition (New Holland Publishers: Australia). Well-illustrated guide to the southern sky, with 100 star charts, photographs by amateur astronomers, and information about telescopes and accessories. The Southern Sky Guide, David Ellyard and Wil Tirion, 2008 (Cambridge University Press: Cambridge). A Walk through the Southern Sky: A Guide to Stars and Constellations and Their Legends, Milton D. Heifetz and Wil Tirion, 2007 (Cambridge University Press: Cambridge). Explorers of the Southern Sky: A History of Astronomy in Australia, R. and R. F. Haynes, D. F. Malin, R. X. McGee, 1996 (Cambridge University Press: Cambridge). Astronomical Objects for Southern Telescopes, E. J. Hartung, Revised and illustrated by David Malin and David Frew, 1995 (Melbourne University Press: Melbourne). An indispensable source of information for observers of southern sky, with vivid descriptions and an extensive bibliography. Astronomy of the Southern Sky, David Ellyard, 1993 (HarperCollins: Pymble, N.S.W.). An introductory-level popular book about observing and making sense of the night sky, especially the southern hemisphere. Under Capricorn: A History of Southern Astronomy, David S. Evans, 1988 (Adam Hilger: Bristol). An excellent history of the development of astronomy in the southern hemisphere, with a good bibliography that names original sources. The Southern Sky: A Practical Guide to Astronomy, David Reidy and Ken Wallace, 1987 (Allen and Unwin: Sydney). A comprehensive history of the discovery and exploration of the southern sky, from the earliest European voyages of discovery to the modern age. Exploring the Southern Sky, S.
    [Show full text]