“Aristarchos” Telescope Tel: +30-2310-998185 Manolis Plionis the European Southern Observatory Fax: +30-2310-995384 & Ioannis Georgantopoulos

Total Page:16

File Type:pdf, Size:1020Kb

“Aristarchos” Telescope Tel: +30-2310-998185 Manolis Plionis the European Southern Observatory Fax: +30-2310-995384 & Ioannis Georgantopoulos HIPPARCHOSHIPPARCHOS The Hellenic Astronomical Society Newsletter Volume 2, Issue 3 SPECIAL ISSUE: Present Status of the Hellenic Observational Astronomy ISSN: 1790-9252 Contents HIPPARCHOSHIPPARCHOS Volume 2, Issue 3 • September 2007 ISSN: 1790-9252 Special Issue: Present Status of the Hellenic Observational Astronomy Hipparchos publishes review papers, Editor: Manolis Plionis news and comments on topics of in- terest to astronomers, including mat- Message from the President. 2 The Skinakas Observatory in Crete: a short ters concerning members of the Hel- description of its infrastructure and activities The Helmos Observatory lenic Astronomical Society I. Papadakis & Y. Papamastorakis . 26 C. Goudis, P. Boumis, P. Hantzios, Editor: Kostas Kokkotas E. Xilouris, A. Dapergolas . 4 The Gerostathopoulio Observatory of the National & Kapodistrian Department of Physics, The Vernikos-Eugenides University of Athens Aristotle University of Thessaloniki, Wide Field CCD Camera P.G. Niarchos & P.G. Laskarides . 27 Thessaloniki 54124, Greece. of the 2.3m “Aristarchos” telescope Tel: +30-2310-998185 Manolis Plionis The European Southern Observatory Fax: +30-2310-995384 & Ioannis Georgantopoulos . 10 Iason Spyromilios . 30 Email: [email protected] The birth of “ARISTARCHOS” Participation of the Institute Editorial Advisors Evangelos Kontizas . 13 for Space Applications and Remote • V. Charmandaris (Crete) Sensing of the National Observatory The Kryoneri Observatory • D. Hatzidimitriou (Crete) of Athens in space science programs C. Goudis, A. Dapergolas, E. Xilouris, • M. Plionis (Athens) Ioannis A. Daglis, Anastasios Anastasiadis, P. Boumis . 15 • J.H. Seiradakis (Thessaloniki) Georgios Balasis, Anna Belehakis . 34 • N.K. Stergioulas (Thessaloniki) DIMM sampling of the “seeing” Observational X-ray Astronomy in Greece • K. Tsinganos (Athens) at Kryonerion I. Georgantopoulos, I. Papadakis, D. Mislis, E.T. Harlaftis, D. Buckley, Printed by ZITI Publications • www.ziti.gr M. Plionis . 36 K. Gazeas, K. Stathoulis, G. Dimou, J.-H. Seiradakis . 18 The Herschel Space Observatory and the Greek Involvement The Image quality E. M. Xilouris . 37 of the 1.2m telescope of the National Observatory of Athens Observations of the Sun Sue Worswick, Emilios T. Harlaftis, at the National Observatory of Athens George Dimou . 22 G. Tsiropoula & K. Tziotziou . 38 Message from the President Dear Hel.A.S. members, hus, C. Goudis et al. introduce us to This is a special issue of Hipparchos Tthe Helmos Astronomical Station Cover photo: devoted to Hellenic Observational As- which houses the most awaited new Hel- A space probe and tronomy: from the smaller University lenic astronomical instrument, the “Aris- the ARISTARCHOS telescope. telescopes and the historical Kryonerion tarchos” 2.3m telescope. In addition to telescope, to the new 2.3m “Aristarchos”, providing the structure, optics, perform- Editorial assistance now at the final stages of commissioning, ance and instrumentation of the tele- is needed! to the giant, state of the art, ESO tele- scope the article shows some of its “first To improve the contents of scopes and to the great space observa- light” images. The telescope will soon Hipparchos please provide us with tories. The issue provides the reader with be fully operational, providing excellent information related to your Insti- the satisfaction that in all those steps of observations with image quality <0.35”. tute or with exciting news from the ladder to the sky and the Universe It is important to note it will be auto- your field of research. there is a vibrant Hellenic involvement, mated and remotely controlled through of one form or another. the network. M. Plionis & I. Georganto- Message from the President (continued) poulos outline the technical details and Physics of the University of Athens. This space observatories and ESO one may feel the science of the new wide-field (10.1’ small but well equipped telescope not the satisfaction that the nation has final- x 10.1’) Vernikou-Eugenides CCD imag- only has been playing a catalytic role in ly built one of the greatest telescopes in ing camera (VEC) to be installed on the the astronomical education offered at the continental Europe (Aristarchos) and also “Aristarchos” telescope. VEC will provide University of Athens at the undergradu- has recently joined ESA. At the same time unique opportunities to undertake a rela- ate and postgraduate level, but the tele- however, one may wonder why Greece is tively high spatial resolution, deep, broad scope’s modern instrumentation enables not yet a member of the great ESO as- band imaging surveys of selected areas of it to carry out some specialized research tronomical organization, despite the unani- the sky, searching for extrasolar planets programs and participate in international mous call of an international experts com- and various transient objects, studying the networks for the observation of variable mittee that joining ESO should be the top physics of star formation in our galaxy and stars, as shown in the article. astronomy priority for the nation (Ter- other ones, stellar populations, galaxy for- zian report, mation and evolution, large scale structure, Daglis et al present the wide re- http://www.astro.noa.gr/gnca/NEWS/ etc. E. Kontizas, among the key people who search activities of the Institute for ca-report2000.htm, made Aristarchos a reality, describes the SpaceI. Applications and Remote Sensing first steps in the long process of building of NOA, in particular in this new era that the cost is a one-time entrance fee of the telescope focussing on the details orig- the country has joined ESA, while G. Tsi- about 10 million €, i.e., similar to the inal proposal to the Greek government in ropoula and K. Tziotziou present solar ESA annual membership fee, and an an- 1996 which was officially approved by the observations at ISARS/NOA. I. Georgan- nual membership fee of about 1 million General Secretariat of Research & Tech- topoulos, I. Papadakis and M. Plionis sum- €). Clearly the benefits of joining the Eu- nology in November 1997. marize the Observational X-ray Astron- ropean Southern Observatory, the ma- omy activities in Greece and finally E. M. jor astronomical organization of Europe, ext, C. Goudis, et al. describe the 1.2 Xilouris the upcoming Herschel Space are multiple and there is no doubt that m telescope of the National Ob- Observatory in which there is also a Hel- it is a worthwhile investment. The GC servatoryN of Athens situated at 22 km lenic participation. of the Hel.A.S. firmly believes, that this SW from Kiato Corinthias, near the vil- should be the next goal for the Greek lage of Kryonerion at a height of 930 m. Spyromilios, provides a panoramic astronomy. This historical, for the Hellenic Astron- view of the impressive state of the omy, telescope, which is equipped with artI. ESO telescopes and equipments, the ue to lack of space in this special several instruments, used in the past to product of the European active collabora- issue we mainly concentrated to perform mainly photometric and spectro- tion on La Silla (the 3.6-m telescope, the theD larger Hellenic telescopes. That by graphic observations, seems to also have NTT and the 2.2-m telescope, etc), Cer- no means should be interpreted that we a modern future: an agreement recently ro Paranal (the four very well equipped do not appreciate the role of the small- has been reached with members of the 8.2-m Unit Telescopes known as the VLT), er ones, in particular, in Astronomy ed- Cork Institute of Technology, Ireland, to APEX and the under-construction Atac- ucation (Michalitsianos, Ioannina, Stephan- fund, upgrade and robotize the telescope. ama Large Millimetre Array (ALMA). It is ion), or, public outreach (NOA, Penteli). All Then there are two articles on the image also noted that recently the ESO Council have their place and contribution in the quality of the 1.2m Kryonerion telescope decided to go ahead with the construc- present status of Hellenic Observational by Sue Worswick et al and D. Mislis, et al, tion of the European Extremely Large Astronomy. test-studies of the “seeing” at the Kryo- Telescope (EELT) which will have un- nerion Station during July and October precedented discovery capabilities. The t should be mentioned that the first ar- 2002, wherein they find a median “seeing” exciting science from ESO telescopes is ticles, submitted for this special issue of 0.68 arcseconds and 1.42 arcseconds, also reviewed, for example, finding plan- quiteI some years ago, were co-authored respectively. etary systems to the most exciting limits by the late Emilios Harlaftis, one of the with the recent discovery of Gliese 581c, most aspiring members of the Hellen- Papadakis & Y. Papamastorakis provide the first almost earth-like planet in the ic Observational Astronomy family, who a short description of the Skinakas habitable zone. The quoted statistics is passed away tragically on the 13 February observatory,I. operating in central Crete at remarkable: refereed publications from 2005. For this reason the governing board an altitude of 1750 m and on a site with ESO telescopes exceed 600 per year, with of Hel.A.S. decided to devote this issue to excellent seeing conditions (the median the VLT alone producing more than one Emilios memory. seeing has been measured to be sub-arc paper per day! second) and providing impressive results n addition to the authors of the articles since 1986 (a more detailed article on Ski- n particular, focusing for a moment to for their contributions, I would like to nakas can be found in the previous issue the more sophisticated means of as- alsoI thank Manolis Plionis who did all the of Hipparchos). P.G. Niarchos and P.G. tronomicalI observations and the ladder editing and excellent coordination making Laskarides present the 40 cm telescope to the Universe involving some form of this issue a reality. atop the building of the Department of Hellenic participation, i.e., Aristarchos, the Kanaris Tsinganos HIPPARCHOS | Volume 2, Issue 3 3 The Helmos Observatory by C.
Recommended publications
  • Society News Science News the Antikythera Mechanism Skinakas Observatory Spectroscopic Diagnostics of Galactic Nuclei Eclipsing Binaries
    HIPPARCHOSHIPPARCHOS The Hellenic Astronomical Society Newsletter Volume 2, Issue 2 Society News Science News The Antikythera Mechanism Skinakas observatory Spectroscopic Diagnostics of Galactic Nuclei Eclipsing Binaries ISSN: 1790-9252 ʸ˱ˤ˳˶˱˹˯˩˭ˮˬ˰˱˙ ƋƜƠƦƓ6SHFLDO(GLWLRQ °ĆāąĆąõýĉýĊýĈØĉĊćąăąĂõ÷Ĉ çąÿąĈāóûÿĒĊÿý÷ĉĊćąăąĂõ÷ĆćóĆûÿă÷ûõă÷ÿĆûćõĆāąĀýØČôĉĊû Ċą 1H[6WDU 6( ă÷ ĉ÷Ĉ øąýþôĉûÿ ă÷ øćûõĊû čÿāÿòúûĈ ÷ĉĊóćûĈ Ćā÷ăôĊûĈù÷ā÷ĄõûĈĀ÷ÿòāā÷ĂûĊąĆòĊýĂ÷ûăĒĈĀąċĂĆÿąēÞ ăó÷ ąÿĀąùóăûÿ÷ 1H[6WDU 6( ĉċăúċòüûÿ ĆćďĊąČ÷ăô ûċčćýĉĊõ÷ Ăû ûĄûāÿùĂóăûĈ āûÿĊąċćùõûĈ Ā÷ÿ ÷ĆõĉĊûċĊą āĒùą ÷Ąõ÷Ĉ ĆćąĈ ĊÿĂô Ûûă Ćûćÿā÷ĂøòăûĊ÷ÿ ý Ćÿþ÷ăĒĊýĊ÷ ă÷ Ċą ĂûĊ÷ăÿĔĉûÿ ą ÷ùąć÷ĉĊôĈ ƌƞƢƜƨơƱƠƥ ăó÷ ąÿĀąùóăûÿ÷ 1H[6WDU 6( öÁ &HOHVWURQ ´¹ÅÀ«µ´¸ 1H[6WDU6( ĊýăĊûāûċĊ÷õ÷āóĄýĊýĈĊûčăąāąùõ÷ĈĒĆďĈĆāôćďĈ ÷ċĊąĂ÷ĊąĆąÿýĂóăą āûÿĊąċćùÿĀĒ ĉēĉĊýĂ÷ úċă÷ĊĒĊýĊ÷ ÷ă÷øòþĂÿĉýĈ Ăóĉď IODVK Ċąċ čûÿćÿĉĊýćõąċ ĊÿĈ ĀąćċČ÷õûĈ ãæäêÜâæ 1H[6WDU6( êëçæé 0DNVXWRY&DVVHJUDLQ¡¾»¿¾Ã¸¹Ë*R7R ûĆÿĉĊćĔĉûÿĈ 6WDU%ULJKW ;/7 Ċą ûĆ÷ă÷ĉĊ÷ĊÿĀĒ āąùÿĉĂÿĀĒ ÛàØãÜêèæéáØêæçêèæë PP l ûċþċùćòĂĂÿĉýĈĊąċĊýāûĉĀąĆõąċ6N\$OLJQpĀ÷ÿĆąāāòòāā÷ ÜéêØçæéêØéÞ PP ÜéêâæÚæé I £¢ ¢£¡¨¢¢ 6WDU%ULJKW;/7 ãûĊą1H[6WDU6(ûõĉĊûĉĊýþóĉýĊąċąúýùąēØĆāòûĆÿāóĄĊû ãÜÚïìÜâãÜÚÜßëäéÞ [ óă÷÷ăĊÿĀûõĂûăą÷ĆĒĊąĂûăąēĀ÷ÿĊąĊýāûĉĀĒĆÿąþ÷Ċąøćûÿùÿ÷ æèàØáæìØàäãÜÚÜßæé éêÞèàåÞ ØāĊ÷üÿĂąċþÿ÷Āô»´»¾Ã¬À ĉ÷ĈíćýĉÿùƹÿĔăĊ÷ĈĊýăĊûčăąāąùõ÷1H[6WDUĊ÷ĊýāûĉĀĒĆÿ÷ ¡¢¥ PP PP(/X[ 6( óčąċă Ċýă ÿĀ÷ăĒĊýĊ÷ ă÷ ûăĊąĆõĉąċă ĆûćõĆąċ ¡¤£¢ 6WDU3RLQWHU ÷ăĊÿĀûõĂûă÷ êą ĂĒăą Ćąċ óčûĊû ă÷ ĀòăûĊû ûõă÷ÿ ă÷ ĀąÿĊòĄûĊû £¡ ¢ 뺸¼¾Á ¨ PP »´kIOLSPLUURUl Ăóĉ÷÷ĆĒĊąĆćąĉąČþòāĂÿąĀ÷ÿă÷÷Ćąā÷ēĉûĊûĊąþó÷Ă÷ ÙØèæé NJ Ûûă ĄóćûĊû Ćąÿą ÷ăĊÿĀûõĂûăą ă÷ ûĆÿāóĄûĊû
    [Show full text]
  • Project's User Guide
    User guide Editors: Sofoklis Sotirou, Nikolaos Dalamagkas Artwork: Sylvia Pentheroudaki, Evaggelos Anastasiou Ellinogermaniki Agogi This edition is co-financed by European Commission Copyright 2006 by Ellinogermaniki Agogi All rights reserved Reproduction or translation of any part of this work without the written permission of the copyright owners is unlawful. Request for permission or further information should be addressed to the copyright owners. Printed by Epinoia S.A. 4 Contents For the user of the D-Space service p.7 Chapter 1 p.9 1 The D-Space project p.11 Chapter 2 p.15 2 Technical description of the D-Space service p.17 2.1 The D-Space network of robotic telescopes p.17 2.2 The D-Space user interface p.21 2.2.1 Go observing p.23 2.2.2 The D-Space Resource Center p.25 2.2.3 The D-Space Communication Area p.25 Chapter 3 p.27 3 Scenarios of use p.29 3.1 Scenarios of use in formal learning settings p.29 3.2 Scenarios of Use in informal learning settings p.31 Appendix p.37 References p.47 5 6 For the user of the D-Space service The Discovery Space (D-Space) project focuses on the educational use of a network of remotely controlled telescopes. The aim of this short guide is to support the teach- ers in using the service. This Guide aims also to help users (teachers, students, astronomers, visitors of sci- ence parks and museums) to use the D-Space service in the optimum way.
    [Show full text]
  • Progress in Multi-Wavelength and Multi-Messenger Observations of Blazars and Theoretical Challenges
    Article Progress in Multi-Wavelength and Multi-Messenger Observations of Blazars and Theoretical Challenges Markus Böttcher Centre for Space Research, North-West University, Potchefstroom 2520, South Africa; [email protected]; Tel.: +27-18-299-2418 Received: 6 November 2018; Accepted: 9 January 2019; Published: 18 January 2019 Abstract: This review provides an overview of recent advances in multi-wavelength and multi-messenger observations of blazars, the current status of theoretical models for blazar emission, and prospects for future facilities. The discussion of observational results will focus on advances made possible through the Fermi Gamma-Ray Space Telescope and ground-based gamma-ray observatories (H.E.S.S., MAGIC, VERITAS), as well as the recent first evidence for a blazar being a source of IceCube neutrinos. The main focus of this review will be the discussion of our current theoretical understanding of blazar multi-wavelength and multi-messenger emission, in the spectral, time, and polarization domains. Future progress will be expected in particular through the development of the first X-ray polarimeter, IXPE, and the installation of the Cherenkov Telescope Array (CTA), both expected to become operational in the early to mid 2020s. Keywords: active galaxies; blazars; multi-wavelength astronomy; muti-messenger astronomy; neutrino astrophysics; polarization 1. Introduction Blazars are the class of jet-dominated, radio-loud active galactic nuclei (AGN) whose relativistic jets point close to our line of sight. Due to this viewing geometry, all emissions from a region moving 2 −1/2 with Lorentz factor G ≡ (1 − bG) , where bGc is the jet speed, along the jet, at an angle qobs with −1 respect to our line of sight, will be Doppler boosted in frequency by a factor d = (G[1 − bG cos qobs]) and in bolometric luminosity by a factor d4 with respect to quantities measured in the co-moving frame of the emission region.
    [Show full text]
  • Multi-Band Intra-Night Optical Variability of BL Lacertae
    Article Multi-Band Intra-Night Optical Variability of BL Lacertae Haritma Gaur 1,*, Alok C. Gupta 2, Rumen Bachev 3, Anton Strigachev 3, Evgeni Semkov 3, Paul J. Wiita 4,5, Minfeng Gu 1 and Sunay Ibryamov 6 1 Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, China; [email protected] 2 Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital 263002, India; [email protected] 3 Institute of Astronomy and National Astronomical Observatory, Bulgarian Academy of Sciences, 72 Tsarigradsko Shosse Blvd., 1784 Sofia, Bulgaria; [email protected] (R.B); [email protected] (A.S); [email protected] (E.S) 4 Department of Physics, The College of New Jersey, P.O. Box 7718, Ewing, NJ 08628-0718, USA; [email protected] 5 Kavli Institute for Particle Astrophysics and Cosmology, SLAC, 2575 Sand Hill Rd, Menlo Park, CA 94025, USA 6 Department of Theoretical and Applied Physics, Faculty of Natural Sciences, University of Shumen, 115, Universitetska Str., 9712 Shumen, Bulgaria; [email protected] * Correspondence: [email protected] Received: 30 October 2017; Accepted: 5 December 2017; Published: 8 December 2017 Abstract: We monitored BL Lacertae frequently during 2014–2016 when it was generally in a high state. We searched for intra-day variability for 43 nights using quasi-simultaneous measurements in the B, V, R, and I bands (totaling 143 light curves); the typical sampling interval was about eight minutes. On hour-like timescales, BL Lac exhibited significant variations during 13 nights in various optical bands.
    [Show full text]
  • Optical Counterpart to Swift J0243. 6+ 6124
    Astronomy & Astrophysics manuscript no. ms c ESO 2020 September 23, 2020 Optical counterpart to Swift J0243.6+6124 P. Reig1, 2, J. Fabregat3, and J. Alfonso-Garzón4 1 Institute of Astrophysics, Foundation for Research and Technology-Hellas, 71110 Heraklion, Greece 2 Physics Department, University of Crete, 71003 Heraklion, Greece e-mail: [email protected] 3 Observatorio Astronómico, Universidad de Valencia, Catedrático José Beltrán 2, 46980 Paterna, Spain 4 Centro de Astrobiología-Departamento de Astrofísica (CSIC-INTA), Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Spain Received ; accepted ABSTRACT Context. Swift J0243.6+6124 is a unique system. It is the first and only ultra-luminous X-ray source in our Galaxy. It is the first and only high-mass Be X-ray pulsar showing radio jet emission. It was discovered during a giant X-ray outburst in October 2017. While there are numerous studies in the X-ray band, very little is known about the optical counterpart. Aims. Our aim is to characterize the variability timescales in the optical and infrared bands in order to understand the nature of this intriguing system. Methods. We performed optical spectroscopic observations to determine the spectral type. Long-term photometric light curves to- gether with the equivalent width of the Hα line were used to monitor the state of the circumstellar disk. We used BVRI photometry to estimate the interstellar absorption and distance to the source. Continuous photometric monitoring in the B and V bands allowed us to search for intra-night variability. Results. The optical counterpart to Swift J0243.6+6124 is a V = 12.9, O9.5Ve star, located at a distance of ∼ 5 kpc.
    [Show full text]
  • Long-Term Variability of High-Mass X-Ray Binaries. I. Photometry? P
    Astronomy & Astrophysics manuscript no. ms_charts c ESO 2018 October 16, 2018 Long-term variability of high-mass X-ray binaries. I. Photometry? P. Reig1; 2 and J. Fabregat3 1 IESL, Foundation for Research and Technology-Hellas, 71110, Heraklion, Greece 2 Physics Department, University of Crete, 71003, Heraklion, Greece e-mail: [email protected] 3 Observatorio Astronómico, Universidad de Valencia, E-46100 Burjassot, Spain Received ; accepted ABSTRACT We present photometric observations of the field around the optical counterparts of high-mass X-ray binaries. Our aim is to study the long-term photometric variability in correlation with their X-ray activity and derive a set of secondary standard stars that can be used for time series analysis. We find that the donors in Be/X-ray binaries exhibit larger amplitude changes in the magnitudes and colours than those hosting a supergiant companion. The amplitude of variability increases with wavelength in Be/X-ray binaries and remains fairly constant in supergiant systems. When time scales of years are considered, a good correlation between the X-ray and optical variability is observed. The X-rays cease when optical brightness decreases. These results reflect the fact that the circumstellar disk in Be/X-ray binaries is the main source of both optical and X-ray variability. We also derive the colour excess, E(B − V), selecting data at times when the contribution of the circumstellar disk was supposed to be at minimum, and we revisit the distance estimates. Key words. X-rays: binaries – stars: neutron – stars: binaries close –stars: emission line, Be 1.
    [Show full text]
  • Section of Astrophysics & Space Physics: 2004 Annual Report
    UNIVERSITY OF CRETE DEPARTMENT OF PHYSICS SECTION OF ASTROPHYSICS & SPACE PHYSICS ANNUAL REPORT FOR 2004 TABLE OF CONTENTS 1. Introduction 1 2. Staff 1 3. Facilities 1 3.1. Skinakas Observatory 1 3.2. Ionospheric Physics Laboratory 2 4. Teaching 3 5. Scientific Research 3 5.1. Theoretical Astrophysics 3 5.2. Observational Astrophysics 4 5.2.1. Observational Galactic Astrophysics 4 5.2.2. Observational Extragalactic Astrophysics 5 5.3 Atmospheric & Ionospheric Physics 6 6. Research Funding 7 7. Collaborations with other institutes 7 8. National & International Committees 8 9. Publications 8 10. Contact 11 Univ. of Crete, Dept. of Physics Section of Astrophysics & Space Physics 2004 Annual Report 1. INTRODUCTION The present document summarizes the activities of the members of the Section of Astrophysics and Space Physics at the Department of Physics of the University of Crete, during the 2004 calendar year. The staff of the Section consisted of 11 PhD research scientists, 5 graduate students and 4 technicians. Members of the Section were involved in teaching undergraduate and graduate courses in the University of Crete, while doing research in the fields of theoretical and observational astrophysics, as well as in atmospheric and ionospheric physics. Their work has been funded by national and international research grants, and in 2004, it resulted in 37 papers published in international refereed journals. Significant efforts were also devoted in the operation and improvement of the infrastructure and hardware at Skinakas Observatory and the Ionospheric Physics Laboratory. This document was prepared in April 2005, based on contributions from all members of the Section.
    [Show full text]
  • The Large Amplitude Outburst of the Young Star HBC 722 in NGC 7000/IC 5070 Tral Lines, the Only Three Lines Visible in Emission in Their Spec- Tra
    Astronomy & Astrophysics manuscript no. Semkov c ESO 2021 July 7, 2021 Letter to the Editor The large amplitude outburst of the young star HBC 722 in NGC 7000/IC 5070, a new FU Orionis candidate E. H. Semkov1, S. P. Peneva1, U. Munari2, A. Milani3, and P. Valisa3 1 Institute of Astronomy and National Astronomical Observatory, Bulgarian Academy of Sciences, 72 Tsarigradsko Shose blvd., BG-1784 Sofia, Bulgaria, e-mail: [email protected] 2 INAF Osservatorio Astronomico di Padova, Sede di Asiago, I-36032 Asiago (VI), Italy 3 ANS Collaboration, Astronomical Observatory, I-36012 Asiago (VI), Italy Received ; accepted ABSTRACT Context. The investigations of the photometric and spectral variability of PMS stars are essential to a better understanding of the early phases of stellar evolution. We are carrying out a photometric monitoring program of some fields of active star formation. One of our targets is the dark cloud region between the bright nebulae NGC 7000 and IC 5070. Aims. We report the discovery of a large amplitude outburst from the young star HBC 722 (LkHα 188 G4) located in the region of NGC 7000/IC 5070. On the basis of photometric and spectroscopic observations, we argue that this outburst is of the FU Orionis type. Methods. We gathered photometric and spectroscopic observations of the object both in the pre-outburst state and during a phase of increase in its brightness. The photometric BVRI data (Johnson-Cousins system) that we present were collected from April 2009 to September 2010. To facilitate transformation from instrumental measurements to the standard system, fifteen comparison stars in the field of HBC 722 were calibrated in the BVRI bands.
    [Show full text]
  • Discovery of the Optical Counterpart to the X-Ray Pulsar SAX J2103.5+4545
    A&A 421, 673–680 (2004) Astronomy DOI: 10.1051/0004-6361:20035786 & c ESO 2004 Astrophysics Discovery of the optical counterpart to the X-ray pulsar SAX J2103.5+4545 P. Reig 1,4, I. Negueruela2,J.Fabregat3,R.Chato1,P.Blay1, and F. Mavromatakis4 1 GACE, Instituto de Ciencias de los Materiales, Universitad de Valencia, 46071 Paterna-Valencia, Spain e-mail: [pere.blay; rachid.chato]@uv.es 2 Departamento de F´ısica, Ingenier´ıa de Sistemas y Teor´ıa de la Se˜nal, Universidad de Alicante, 03080 Alicante, Spain e-mail: [email protected] 3 Observatorio Astron´omico de Valencia, Universitad de Valencia, 46071 Paterna-Valencia, Spain e-mail: [email protected] 4 University of Crete, Physics Department, PO Box 2208, 710 03 Heraklion, Crete, Greece e-mail: [email protected] Received 2 December 2003 / Accepted 26 March 2004 Abstract. We report optical and infrared photometric and spectroscopic observations that identify the counterpart to the 358.6-s X-ray transient pulsar SAX J2103.5+4545 with a moderately reddened V = 14.2 B0Ve star. This identification makes SAX J2103.5+4545 the Be/X-ray binary with the shortest orbital period known, Porb = 12.7 days. The amount of absorption to the system has been estimated to be AV = 4.2 ± 0.3, which for such an early-type star implies a distance of about 6.5 kpc. The optical spectra reveal major and rapid changes in the strength and shape of the Hα line. The Hα line was ini- tially observed as a double peak profile with the ratio of the intensities of the blue over the red peak greater than one (V/R > 1).
    [Show full text]
  • New Planerary Nebulae Towards the Galactic Bulge
    Planetary Nebulae in Our Galaxy and Beyond Proceedings IAU Symposium No. 234, 2006 c 2006 International Astronomical Union M. J. Barlow & R. H. M´endez, eds. DOI: 00.0000/X000000000000000X New Planerary Nebulae towards the Galactic bulge P. Boumis1, S. Akras1, P. A. M. van Hoof2, G. C. Van de Steene2, J. Papamastorakis3 and J. A. Lopez4 1Institute of Astronomy & Astrophysics, National Observatory of Athens, I. Metaxa & V. Pavlou, GR-152 36 P. Penteli, Athens, Greece 2 Royal Observatory of Belgium, Ringlaan 3, B-1180 Brussels, Belgium 3 Department of Physics, University of Crete, GR-710 03 Heraklion, Crete, Greece 4 Instituto de Astronoma, UNAM, Apdo. Postal 877, Ensenada, BC 22800, Mexico Abstract. New Planetary Nebulae (PNe) were discovered through an [O iii] 5007 A˚ emission line survey in the Galactic bulge region with l> 0◦. We detected 240 objects, including 44 new PNe. Deep Hα+[N ii] CCD images as well as low resolution spectra were obtained for the new PNe in order to study them in detail. Preliminary photo–ionization models of the new PNe with Cloudy resulted in first estimates of the physical parameters and abundances. They are compared to the abundances of Galactic PNe. Keywords. surveys, ISM: abundances, ISM: planetary nebulae: general. 1. Introduction Galactic Planetary Nebulae (PNe) are of great interest because of their important role in the chemical enrichment history of the interstellar medium as well as in the stellar evolution of our Galaxy (Beaulieu et al. 2000 and references therein). Many surveys have been made in the past in order to discover new PNe (Boumis et al.
    [Show full text]
  • Astronomy, Astrophysics, and Space Physics in Greece
    Paper to be published in “Organizations and Strategies in Astronomy – Vol. 7, Ed. A. Heck, 2006, Springer, Dordrecht.” A Preprint typeset using LTEX style emulateapj v. 6/22/04 ASTRONOMY, ASTROPHYSICS & SPACE PHYSICS IN GREECE Vassilis Charmandaris1 University of Crete, Department of Physics, P. O. Box 2208, GR-71003, Heraklion, Greece Paper to be published in “Organizations and Strategies in Astronomy – Vol. 7, Ed. A. Heck, 2006, Springer, Dordrecht.” ABSTRACT In the present document I review the current organizational structure of Astronomy, Astrophysics and Space Physics in Greece. I briefly present the institutions where professional astronomers are pursuing research, along with some notes of their history, as well as the major astronomical facilities currently available within Greece. I touch upon topics related to graduate studies in Greece and present some statistics on the distribution of Greek astronomers. Even though every attempt is made to substantiate all issues mentioned, some of the views presented have inevitably a personal touch and thus should be treated as such. Subject headings: 1. INTRODUCTION fessor and Full Professor. A minimum of three years is The framework within which astronomers – a term that required on each rank before applying for promotion the will be used rather loosely in the rest of the document to next. Tenure is obtained upon successful evaluation after indicate individuals performing research in Astronomy, spending three years at the level of Assistant Professor. Astrophysics and Space Physics (AA&SP) – have been A university faculty can, in principle pursue his/her own functioning in Greece is not too different from other Eu- research direction, teach courses, and supervise graduate ropean countries.
    [Show full text]
  • The Physical Structure of the Planetary Nebula NGC 6781
    A&A 374, 280–287 (2001) Astronomy DOI: 10.1051/0004-6361:20010752 & c ESO 2001 Astrophysics The physical structure of the planetary nebula NGC 6781 F. Mavromatakis1, J. Papamastorakis1,2, and E. V. Paleologou2 1 University of Crete, Physics Department, PO Box 2208, 710 03 Heraklion, Crete, Greece 2 Foundation for Research and Technology-Hellas, PO Box 1527, 711 10 Heraklion, Crete, Greece Received 22 March 2001 / Accepted 15 May 2001 Abstract. The planetary nebula NGC 6781 was imaged in major optical emission lines. These lines allow us to construct maps of the projected, two dimensional Balmer decrement, electron density, electron temperature, ionization and abundance structure. The average electron density, determined from the [S ii] lines, is ∼500 cm−3, while the electron temperature distribution, determined from the [N ii] lines, is flat at ∼10 000 K. The Balmer decrement map shows that there are variations in extinction between the north and south areas of the planetary nebula. The higher extinction observed to the north of the central star is probably caused by dust spatially associated with CO emission at blue–shifted velocities. The [N ii] image reveals the known optical halo, at a flux level of ∼0.2% of the strong shell emission in the east, but now the angular extent of 21600×19000 is much larger than previous measurements. The halo is also present in [O iii], where we measure an extent of 19000×16200.The ionization maps indicate substantial ionization along the caps of the ellipsoid as well as in the halo. The maps also show a sharp decrease in ionization along the outer edge of the shell in the west and the east, south–east.
    [Show full text]