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The Kinematic Signature of the Galactic Warp in Gaia DR1-I. the Hipparcos Subsample
Astronomy & Astrophysics manuscript no. WarpGaia c ESO 2021 September 26, 2021 The kinematic signature of the Galactic warp in Gaia DR1 I. The Hipparcos sub-sample E. Poggio1; 2, R. Drimmel2, R. L. Smart2; 3, A. Spagna2, and M. G. Lattanzi2 1 Università di Torino, Dipartimento di Fisica, via P. Giuria 1, 10125 Torino, Italy 2 Osservatorio Astrofisico di Torino, Istituto Nazionale di Astrofisica (INAF), Strada Osservatorio 20, 10025 Pino Torinese, Italy 3 School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK ABSTRACT Context. The mechanism responsible for the warp of our Galaxy, as well as its dynamical nature, continues to remain unknown. With the advent of high precision astrometry, new horizons have been opened for detecting the kinematics associated with the warp and constraining possible warp formation scenarios for the Milky Way. Aims. The aim of this contribution is to establish whether the first Gaia data release (DR1) shows significant evidence of the kinematic signature expected from a long-lived Galactic warp in the kinematics of distant OB stars. As the first paper in a series, we present our approach for analyzing the proper motions and apply it to the sub-sample of Hipparcos stars. Methods. We select a sample of 989 distant spectroscopically-identified OB stars from the New Reduction of Hipparcos (van Leeuwen 2008), of which 758 are also in the first Gaia data release (DR1), covering distances from 0.5 to 3 kpc from the Sun. We develop a model of the spatial distribution and kinematics of the OB stars from which we produce the probability distribution functions of the proper motions, with and without the systematic motions expected from a long-lived warp. -
October 2015 BRAS Newsletter
October, 2015 Next Meeting: Monday, Oct. 12th at 7pm at the HRPO Lunar Eclipse on Sept 27th, 2015. Image by BRAS member David Leadingham, one of the few that got a clear view for a couple of minutes through the clouds in our area! Click on the pic for more info on upcoming eclipses What's In This Issue? President's Message AstroShort: Simulating the Universe Secretary's Summary of Sept. Meeting Message From the HRPO Recent BRAS Forum Entries 20/20 Vision Campaign Observing Notes by John Nagle (He's Back!) President's Message “Astronomy is useful because it raises us above ourselves; it is useful because it is grand. It shows us how small is man’s body, how great his mind, since his intelligence can embrace the whole of this dazzling immensity, where his body is only an obscure point, and enjoy its silent harmony." – Henri Poincare, 19th Century mathematician and physicist We all have our reasons for being involved in astronomy. That quote elegantly expresses just one man’s thoughts. What attracted you to astronomy? What do you tell people who ask? I think we all have experienced some indefinable draw to the night sky and the wonders of the universe. Maybe that is it. Wonder. At least for me it is. Wonder, beauty, harmony, perspective. Where does it end? Think about those things and let me know if you have something about that you would like to say at our next meeting. Alternately, you could write up something for this newsletter. Well the total lunar eclipse certainly was a washout. -
Variable Star Section Circular
British Astronomical Association VARIABLE STAR SECTION CIRCULAR No 112, June 2002 Contents Light Curves for some Eclipsing Binary Stars .............................. inside covers From the Director ............................................................................................. 1 Change in E-mail Address for Computer Secretary ......................................... 1 Letters ............................................................................................................... 2 Information on Photometry Available .............................................................. 2 Change to September Circular Deadline .......................................................... 2 The Fade of UY Cen ........................................................................................ 3 Meauring Times of Minimum of EBs using a CCD camera ............................ 4 Photometric Calibration of an MX516 CCD Camera ...................................... 7 Recent Papers on Variable Stars .................................................................... 14 IBVS............................................................................................................... 15 Eclipsing Binary Predictions .......................................................................... 18 ISSN 0267-9272 Office: Burlington House, Piccadilly, London, W1V 9AG PRELIMINARY ECLIPSING BINARY LIGHT CURVES TONY MARKHAM Here are some light curves showing the recent behaviour of some Eclipsing Binaries. The light curves for RZ Cas, Beta -
Atmospheric Activity in Red Dwarf Stars
CONTENTS SUMMARY AND CONCLUSIONS PAPERS ON CHROMOSPHERIC LINES IN RED DWARF FLARE STARS I. AD LEONIS AND GX ANDROMEDAE B. R. Pettersen and L. A. Coleman, 1981, Ap.J. 251, 571. II. EV LACERTAE, EQ PEGASI A, AND V1054 OPHIUCHI B. R. Pettersen, D. S. Evans, and L. A. Coleman, 1984, Ap.J. 282, 214. III. AU MICROSCOPII AND YY GEMINORUM B. R. Pettersen, 1986, Astr. Ap., in press. IV. V1005 ORIONIS AND DK LEONIS B. R. Pettersen, 1986, Astr. Ap., submitted. V. EQ VIRGINIS AND BY DRACONIS B. R. Pettersen, 1986, Astr. Ap., submitted. PAPERS ON FLARE ACTIVITY VI. THE FLARE ACTIVITY OF AD LEONIS B. R. Pettersen, L. A. Coleman, and D. S. Evans, 1984, Ap.J.suppl. 5£, 275. VII. DISCOVERY OF FLARE ACTIVITY ON THE VERY LOW LUMINOSITY RED DWARF G 51-15 B. R. Pettersen, 1981, Astr. Ap. 95, 135. VIII. THE FLARE ACTIVITY OF V780 TAU B. R. Pettersen, 1983, Astr. Ap. 120, 192. IX. DISCOVERY OF FLARE ACTIVITY ON THE LOW LUMINOSITY RED DWARF SYSTEM G 9-38 AB B. R. Pettersen, 1985, Astr. Ap. 148, 151. Den som påstår seg ferdig utlært, - han er ikke utlært, men ferdig. 1 ATMOSPHERIC ACTIVITY IN RED DWARF STARS SUMMARY AND CONCLUSIONS Active and inactive stars of similar mass and luminosity have similar physical conditions in their photospheres/ outside of magnetically disturbed regions. Such field structures give rise to stellar activity, which manifests itself at all heights of the atmosphere. Observations of uneven distributions of flux across the stellar disk have led to the discovery of photospheric starspots, chromospheric plage areas, and coronal holes. -
Gravitationally Lensed Quasars: Light Curves, Observational Constraints, Modeling and the Hubble Constant
Universit´ede Li`ege Facult´edes Sciences D´epartement d’Astrophysique, de G´eophysique et d’Oc´eanographie Gravitationally lensed quasars: light curves, observational constraints, modeling and the Hubble constant Artist view of gravitational distortions caused by a hypothetical black hole in front of the Large Magellanic Cloud. Credit: this file is licensed under the Creative Commons Attribution ShareAlike 2.5 license. Virginie Chantry Research Fellow, Belgian National Fund for Scientific Research (FNRS) - December 2009 - Astrophysique et Dissertation realized for the Traitement de l’image acquisition of the grade of Prof. Pierre Magain Doctor of Philosophy in Space Science Supervisor: Pr. dr. Pierre Magain Members of the thesis commitee: Pr. dr. Pierre Magain Dr. Fr´ed´eric Courbin Pr. dr. Hans Van Winckel Jury composed of: Pr. dr. Jean-Claude G´erard as president Pr. dr. Pierre Magain Dr. Fr´ed´eric Courbin Pr. dr. Hans Van Winckel Pr. dr. Jean Surdej Dr. Damien Hutsem´ekers Dr. C´ecile Faure Dr. G´eraldine Letawe Copyright © 2009 V. Chantry To dreamers. May their wish come true. We should do astronomy because it is beautiful and because it is fun. We should do it because people want to know. We want to know our place in the universe and how things happen. John N. Bahcall (1934 - 2005) Abstract The central topic of this thesis is gravitational lensing, a phenomenon that occurs when light rays from a background source pass near a massive object located on the line of sight and are deflected. It is one of the most wonderful observational fact in favour of the General Theory of Relativity (Einstein, 1916). -
How Astronomical Objects Are Named
How Astronomical Objects Are Named Jeanne E. Bishop Westlake Schools Planetarium 24525 Hilliard Road Westlake, Ohio 44145 U.S.A. bishop{at}@wlake.org Sept 2004 Introduction “What, I wonder, would the science of astrono- use of the sky by the societies of At the 1988 meeting in Rich- my be like, if we could not properly discrimi- the people that developed them. However, these different systems mond, Virginia, the Inter- nate among the stars themselves. Without the national Planetarium Society are beyond the scope of this arti- (IPS) released a statement ex- use of unique names, all observatories, both cle; the discussion will be limited plaining and opposing the sell- ancient and modern, would be useful to to the system of constellations ing of star names by private nobody, and the books describing these things used currently by astronomers in business groups. In this state- all countries. As we shall see, the ment I reviewed the official would seem to us to be more like enigmas history of the official constella- methods by which stars are rather than descriptions and explanations.” tions includes contributions and named. Later, at the IPS Exec- – Johannes Hevelius, 1611-1687 innovations of people from utive Council Meeting in 2000, many cultures and countries. there was a positive response to The IAU recognizes 88 constel- the suggestion that as continuing Chair of with the name registered in an ‘important’ lations, all originating in ancient times or the Committee for Astronomical Accuracy, I book “… is a scam. Astronomers don’t recog- during the European age of exploration and prepare a reference article that describes not nize those names. -
THE REFLECTOR Volume 5, Issue 8 November 2006 Editorial
ISSN 1712-4425 PETERBOROUGH ASTRONOMICAL ASSOCIATION THE REFLECTOR Volume 5, Issue 8 November 2006 Editorial he month of October wasn’t very T good for observing, but despite all of that rain there were some high points. Astronaut Chris Hadfield gave a couple of talks in Peterborough on October 26th. In this issue of the Reflector is a picture of our PAA President getting an autograph! At the October 27th PAA meeting we had Steve Dodson for a guest speaker. He talked about his work in astronomy and intrigued us with the mysteries of our universe. Check out an article on all of this and more on pgs. 8-9. Shawna Miles [email protected] Cassiopeia A. taken by the Spitzer Space Telescope. Image credit: NASA/JPL/ Caltech remnants would be mixed and mashed When Cassiopeia A exploded, most Supernova Remnant together in one big cloud. of the original layers flew out in succes- sive order, but some layers went out fast, Finally Explained During the supernova, as the layers while others moved at slower speeds, shot outward, they hit the shockwave depending on where they started. t’s name is Cassiopeia A. The star from the explosion. Materials that hit I was 15 to 20 times the mass of our the shockwave first have had more time For more information go to:http:// Sun. It is located in the Milky Way gal- to heat up into X-rays and visible light. www.nasa.gov/mission_pages/spitzer/ axy, and exploded relatively recently. For We have been able to see these, but main/index.html or http:// years astronomers have been trying to Spitzer has allowed for us to see the www.spitzer.caltech.edu/spitzer figure out how this supernova remnant missing pieces. -
1945Apj. . .102. .318S SIX-COLOR PHOTOMETRY of STARS III. THE
.318S SIX-COLOR PHOTOMETRY OF STARS .102. III. THE COLORS OF 238 STARS OF DIFFERENT SPECTRAL TYPES* Joel Stebbins1 and A. E. Whiteord2 1945ApJ. Mount Wilson Observatory and Washburn Observatory Received June 8,1945 ABSTRACT Colors have been obtained for 238 stars of all spectral types from O to M by measuring intensities i six spectral regions from X 3530 to X 10,300 A (Tables 2 and 3). The early-type stars from O to B3 sho small dispersion in intrinsic color, but many are strongly affected by space reddening. A dozen late-tyx giants in low latitudes are likewise affected. The most marked effect of absolute magnitude is near spe< trum K0, where the colors of dwarfs, ordinary giants, and supergiants are all different {Fig. 1). The observed colors of the stars agree closely with the colors of a black body at suitable temperatur« (Fig. 2). The derived relative color temperatures are based upon the mean of ten stars of spectrum dG with an assumed temperature of 5500°K. On this scale the values are 23,000° for O stars, 11,000° for A( and 5950° for dGO. An alternative scale, with 6700° and spectrum dG2 for the sun, gives 140,000° fc O stars, 16,000° for A0, and 6900° for dGO (Table 7). A definitive zero point for the temperature seal has not been determined. The bluest O and B stars agree very well with each other, but there is still the possibility that all ai slightly affected by space reddening. A dozen bright stars of the Pleiades seem normal for their type. -
A New Measurement of the Hubble Constant and Matter Content of the Universe Using Extragalactic Background Light Γ-Ray Attenuation
The Astrophysical Journal, 885:137 (7pp), 2019 November 10 https://doi.org/10.3847/1538-4357/ab4a0e © 2019. The American Astronomical Society. All rights reserved. A New Measurement of the Hubble Constant and Matter Content of the Universe Using Extragalactic Background Light γ-Ray Attenuation A. Domínguez1 , R. Wojtak2 , J. Finke3 , M. Ajello4 , K. Helgason5 , F. Prada6, A. Desai4 , V. Paliya7 , L. Marcotulli4 , and D. H. Hartmann4 1 IPARCOS and Department of EMFTEL, Universidad Complutense de Madrid, E-28040 Madrid, Spain; [email protected] 2 DARK, Niels Bohr Institute, University of Copenhagen, Lyngbyvej 2, DK-2100 Copenhagen, Denmark; [email protected] 3 U.S. Naval Research Laboratory, Code 7653, 4555 Overlook Avenue SW, Washington, DC 20375-5352, USA 4 Department of Physics and Astronomy, Clemson University, Kinard Lab of Physics, Clemson, SC 29634-0978, USA 5 Science Institute, University of Iceland, IS-107 Reykjavik, Iceland 6 Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía, E-18080 Granada, Spain 7 Deutsches Elektronen-Synchrotron, D-15738 Zeuthen, Germany Received 2019 March 28; revised 2019 September 24; accepted 2019 September 28; published 2019 November 8 Abstract The Hubble constant H0 and matter density Ωm of the universe are measured using the latest γ-ray attenuation results from Fermi-LAT and Cerenkov telescopes. This methodology is based upon the fact that the extragalactic background light supplies opacity for very high energy photons via photon–photon interaction. The amount of γ-ray attenuation along the line of sight depends on the expansion rate and matter content of the universe. This +6.0 −1 −1 +0.06 novel strategy results in a value of H0 = 67.4-6.2 km s Mpc and W=m 0.14-0.07. -
Constellations
Your Guide to the CONSTELLATIONS INSTRUCTOR'S HANDBOOK Lowell L. Koontz 2002 ii Preface We Earthlings are far more aware of the surroundings at our feet than we are in the heavens above. The study of observational astronomy and locating someone who has expertise in this field has become a rare find. The ancient civilizations had a keen interest in their skies and used the heavens as a navigational tool and as a form of entertainment associating mythology and stories about the constellations. Constellations were derived from mankind's attempt to bring order to the chaos of stars above them. They also realized the celestial objects of the night sky were beyond the control of mankind and associated the heavens with religion. Observational astronomy and familiarity with the night sky today is limited for the following reasons: • Many people live in cities and metropolitan areas have become so well illuminated that light pollution has become a real problem in observing the night sky. • Typical city lighting prevents one from seeing stars that are of fourth, fifth, sixth magnitude thus only a couple hundred stars will be seen. • Under dark skies this number may be as high as 2,500 stars and many of these dim stars helped form the patterns of the constellations. • Light pollution is accountable for reducing the appeal of the night sky and loss of interest by many young people as the night sky is seldom seen in its full splendor. • People spend less time outside than in the past, particularly at night. • Our culture has developed such a profusion of electronic devices that we find less time to do other endeavors in the great outdoors. -
Astronomy 1973-2000 Title Index
Astronomy magazine title index 1973-2000 Afocal and Projection Astrophotography, 8/81:57–59 # Afro-American Skylore Studied, 1/79:61 Against All Odds: Matter and Evolution in the Universe, 100 Years on Mars, 6/94:28–39, 28–39 9/84:67–70 10-Meter Keck Telescope to Gain Twin, 8/91:18, 20, 22 Age of Nearby Stars, The, 7/75:22–27, 22–27 11-Mintute Binary?, An, 1/87:85–86 Age of the Universe, The, 7/81:66–71 12 1/2 -inch Ritchey-Chretien, A, 11/82:55–57 Age Paradox, The, 6/93:38–43 12.5 Inch Portaball, The, 3/95:80–85, 80–85 Aid to Long Exposure Astrophotography, An, 10/73:35–39, 35–39 13th Jovian Moon Discovered, 11/74:55 Aiming at Neptune, 11/87:6–17 14th Jovian Moon, 1/76:60 Airborne Assault on Comet Halley, 3/86:90–95 15 Years of Space, 1/77:55 Alan B. Shepard (1923-1998), 11/98:32, 34 169th Meeting of the American Astronomical Society, The, Alcock's Nova Resurges, 2/77:59 4/87:76 ALCON Lands in Rockford, 1/97:32, 34 17th-Century Nova Indicates Novae are More Numerous then Aldebaran's Girth, 7/79:60 Estimated, 5/86:72 Alexis Lives!, 3/94:24 1976 AA: Discovery of a Minor Planet, 6/76:12–13, 12–13, 12–13, Alien Skies, 4/82:90–95 12–13 Alignment By Laser Light, 4/95:82–83, 82–83 1989 Ends With a Leap Second, 12/89:12 A List, The, 2/98:34 1990 Radio-Video Star Party, The, 4/91:26 All About Telesto, 7/84:62 1 Billion Degree Plasma Discovered by Voyager 2, 1/82:64–65 All Eyes on the Comet Crash, 6/94:40–45, 40–45 1st Extragalactic Pulsar Discovered, 2/76:63 All in the Family, 2/93:36–41 1st Shuttle Payload to Study Resources and Environment, -
Constellations
www.astrosociety.org/uitc No. 21 - Fall 1992 © 1992, Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, CA 94112 Constellations Throughout the centuries, people have looked to the stars to help them navigate across open oceans or featureless deserts, know when to plant and harvest, and preserve their myths and folklore. Ancient peoples used the appearance or disappearance of certain stars over the course of each year to mark the changing seasons. To make it easier to "read" this celestial calendar, they grouped the brighter stars into readily recognizable shapes, the constellations. How many constellations are there? Who invented them? Are there obsolete constellations? Where do individual star names come from? Did other cultures also see constellations in the sky? Are all the stars in a constellation the same distance away from us? Are the constellations permanent? TABLE: The Constellations Activity Corner Resources How many constellations are there? Astronomers officially recognize 88 constellations covering the entire sky in the northern and southern hemispheres. Currently, 14 men and women, 9 birds, two insects, 19 land animals, 10 water creatures, two centaurs, one head of hair, a serpent, a dragon, a flying horse, a river and 29 inanimate objects are represented in the night sky (the total comes to more than 88 because some constellations include more than one creature.) It is important to realize that the great majority of star patterns bear little, if any, resemblance to the figures they are supposed to represent and whose name they bear. The ancient constellation-makers probably meant for them to be symbolic, not literal, representations of their favorite animals or fabled heroes, a kind of celestial "Hall of Fame." Who invented them? Our modern constellation system comes to us from the ancient Greeks.