X-Ray Astronomy
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Quantity Symbol Value One Astronomical Unit 1 AU 1.50 × 10
Quantity Symbol Value One Astronomical Unit 1 AU 1:50 × 1011 m Speed of Light c 3:0 × 108 m=s One parsec 1 pc 3.26 Light Years One year 1 y ' π × 107 s One Light Year 1 ly 9:5 × 1015 m 6 Radius of Earth RE 6:4 × 10 m Radius of Sun R 6:95 × 108 m Gravitational Constant G 6:67 × 10−11m3=(kg s3) Part I. 1. Describe qualitatively the funny way that the planets move in the sky relative to the stars. Give a qualitative explanation as to why they move this way. 2. Draw a set of pictures approximately to scale showing the sun, the earth, the moon, α-centauri, and the milky way and the spacing between these objects. Give an ap- proximate size for all the objects you draw (for example example next to the moon put Rmoon ∼ 1700 km) and the distances between the objects that you draw. Indicate many times is one picture magnified relative to another. Important: More important than the size of these objects is the relative distance between these objects. Thus for instance you may wish to show the sun and the earth on the same graph, with the circles for the sun and the earth having the correct ratios relative to to the spacing between the sun and the earth. 3. A common unit of distance in Astronomy is a parsec. 1 pc ' 3:1 × 1016m ' 3:3 ly (a) Explain how such a curious unit of measure came to be defined. Why is it called parsec? (b) What is the distance to the nearest stars and how was this distance measured? 4. -
Galaxy Clusters in Radio → Non-Thermal Phenomena
GalaxyGalaxy ClustersClusters inin radioradio ÎÎ NonNon--thermalthermal phenomenaphenomena Luigina Feretti Istituto di Radioastronomia CNR Bologna, Italy Tonanzintla, GH2005, 4-5 July 2005 Lecture 4 : Radio emission from cluster galaxies: Classical radio galaxies Radio – X-ray interaction Distorted structures: NAT and WAT Radio galaxies filling X-ray cavities Confinement : Trigger of radio emission: radio luminosity function Enhancement of star formation RadiogalaxiesRadiogalaxies X-ray:X-ray: ThermalThermal ggasas Radio:Radio: AA 119119 (z(z == 0.0441)0.0441) RadioRadio GalaxiesGalaxies PerseusPerseus X-rayX-ray ROSAROSATT PSPCPSPC HotHot gasgas NGC 1265 RadioRadio WSRTWSRT 4949 cmcm RadioRadio galaxiesgalaxies NGC 1275 IC310 RadioRadio galaxiesgalaxies ooff highhigh andand lowlow ppowerower havehave quitequite differentdifferent morphologiesmorphologies onon thethe largelarge scalescale (Fanaroff(Fanaroff && RileyRiley 11974)974) CygCyg AA FRFR IIII 24.24.55 -1-1 HighHigh popowewer:r: PP1.41.4 GHzGHz >> 1010 WW HzHz 3C3C 444499 24.524.5 -1-1 LowLow power:power: PP1.41.4 GHzGHz << 1010 WW HzHz FRFR II RADIORADIO GALAXIESGALAXIES ATAT INCREASINGINCREASING RADIORADIO POWERPOWER 1024 W Hz-1 at 1.4 GHz 3C 31 DA 240 4C 73.08 1026.5 W Hz-1 From Atlas of P.Leahy, powers computed With H0=75, q0=0.5 Owen and Ledlow 1994 TheThe radioradio emissionemission fromfrom INDIVIDUALINDIVIDUAL GALAXIESGALAXIES isis foufoundnd ttoo extendextend WELLWELL BEYONDBEYOND thethe physicalphysical sizesize ofof thethe hosthost opticaloptical galaxygalaxy (>(> oror -
Eclipsing Binary Pulsars
Binary Radio Pulsars ASP Conference Series, Vol. 328, 2005 F. A. Rasio and I. H. Stairs Eclipsing Binary Pulsars Paulo C. C. Freire Arecibo Observatory, HC 3 Box 53995, Arecibo, PR 00612, USA Abstract. The ¯rst eclipsing binary pulsar, PSR B1957+20, was discovered in 1987. Since then, 13 other eclipsing low-mass binary pulsars have been found; 12 of these are in globular clusters. In this paper we list the known eclipsing bi- nary pulsars and their properties, with special attention to the eclipsing systems in 47 Tuc. We ¯nd that there are two fundamentally di®erent groups of eclipsing binary pulsars, separated by their companion masses. The less massive systems (M 0:02 M¯) are a product of predictable stellar evolution in binary pulsars. c » The systems with more massive companions (Mc 0:2 M¯) were formed by ex- change encounters in globular clusters, and for that»reason are exclusive to those environments. This class of systems can be used to learn about the neutron star recycling fraction in the globular clusters actively forming pulsars. We suggest that most of these binary systems are undetectable at radio wavelengths. 1. Introduction The ¯rst eclipsing binary pulsar, PSR B1957+12, was discovered in 1987 (Fruchter, Stinebring, & Taylor 1987). Since its discovery, 13 other eclipsing binary pulsars with low-mass companions have been found, these are listed in Table 1, with relevant refer- ences. Of these systems, 12 are found in globular clusters (GCs). To these we add a list of binary systems with companion masses smaller than 0:02 M¯ that are, as we will see, intimately related to a subset of the eclipsing binary systems. -
Could a Nearby Supernova Explosion Have Caused a Mass Extinction? JOHN ELLIS* and DAVID N
Proc. Natl. Acad. Sci. USA Vol. 92, pp. 235-238, January 1995 Astronomy Could a nearby supernova explosion have caused a mass extinction? JOHN ELLIS* AND DAVID N. SCHRAMMtt *Theoretical Physics Division, European Organization for Nuclear Research, CH-1211, Geneva 23, Switzerland; tDepartment of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637; and *National Aeronautics and Space Administration/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 Contributed by David N. Schramm, September 6, 1994 ABSTRACT We examine the possibility that a nearby the solar constant, supernova explosions, and meteorite or supernova explosion could have caused one or more of the comet impacts that could be due to perturbations of the Oort mass extinctions identified by paleontologists. We discuss the cloud. The first of these has little experimental support. possible rate of such events in the light of the recent suggested Nemesis (4), a conjectured binary companion of the Sun, identification of Geminga as a supernova remnant less than seems to have been excluded as a mechanism for the third,§ 100 parsec (pc) away and the discovery ofa millisecond pulsar although other possibilities such as passage of the solar system about 150 pc away and observations of SN 1987A. The fluxes through the galactic plane may still be tenable. The supernova of y-radiation and charged cosmic rays on the Earth are mechanism (6, 7) has attracted less research interest than some estimated, and their effects on the Earth's ozone layer are of the others, perhaps because there has not been a recent discussed. -
RADIO ASTRONOMY OBERVTORY Quarterly Report CHARLOTTESVILLE, VA
1 ; NATIONAL RADIO ASTRONOMY OBSERVATORY Charlottesville, Virginia t PROPERTY OF TH E U.S. G - iM RADIO ASTRONOMY OBERVTORY Quarterly Report CHARLOTTESVILLE, VA. 4 OCT 2 2em , July 1, 1984 - September 30, 1984 .. _._r_.__. _.. RESEARCH PROGRAMS 140-ft Telescope Hours Scheduled observing 1853.75 Scheduled maintenance and equipment changes 205.00 Scheduled tests and calibration 145.25 Time lost due to: equipment failure 122.00 power 3.25 weather 0.25 interference 14.50 The following continuum program was conducted during this quarter. No. Observer Program W193 N. White (European Space Observations at 6 cm of the eclipsing Agency) RS CVn system AR Lac. J. Culhane (Cambridge) J. Kuijpers (Utrecht) K. Mason (Cambridge) A. Smith (European Space Agency) The following line programs were conducted during this quarter. No. Observer Program B406 M. Bell (Herzberg) Observations at 13.9 GHz in search of H. Matthews (Herzberg) C6 H in TMC1. T. Sears (Brookhaven) B422 M. Bell (Herzberg) Observations at 3 cm to search for H. Matthews (Herzberg) C5 H in TMC1 and examination of T. Sears (Brookhaven) spectral features in IRC+10216 thought to be due to HC 9 N or C5 H. B423 M. Bell (Herzberg) Observations at 9895 MHz in an attempt H. Matthews (Herzberg) to detect C3 N in absorption against Cas A. 2 No. Observer Program B424 W. Batria Observations at 9.1 GHz of a newly discovered comet. C216 F. Clark (Kentucky) Observations at 6 cm and 18 cm of OH S. Miller (Kentucky) and H20 to study stellar winds and cloud dynamics. -
Distances and Magnitudes Distance Measurements the Cosmic Distance
Distances and Magnitudes Prof Andy Lawrence Astronomy 1G 2011-12 Distance Measurements Astronomy 1G 2011-12 The cosmic distance ladder • Distance measurements in astronomy are a chain, with each type of measurement relative to the one before • The bottom rung is the Astronomical Unit (AU), the (mean) distance between the Earth and the Sun • Many distance estimates rely on the idea of a "standard candle" or "standard yardstick" Astronomy 1G 2011-12 Distances in the solar system • relative distances to planets given by periods + Keplers law (see Lecture-2) • distance to Venus measured by radar • Sun-Earth = 1 A.U. (average) • Sun-Jupiter = 5 A.U. (average) • Sun-Neptune = 30 A.U. (average) • Sun- Oort cloud (comets) ~ 50,000 A.U. • 1 A.U. = 1.496 x 1011 m Astronomy 1G 2011-12 Distances to nearest stars • parallax against more distant non- moving stars • 1 parsec (pc) is defined as distance where parallax = 1 second of arc in standard units D = a/✓ (radians, metres) in AU and arcsec D(AU) = 1/✓rad = 206, 265/✓00 in parsec and arcsec D(pc) = 1/✓00 nearest star Proxima Centauri 1.30pc Very hard to measure less than 0.1" 1pc = 206,265 AU = 3.086 x 1016m so only good for stars a few parsecs away... until launch of GAIA mission in 2014..... Astronomy 1G 2011-12 More distant stars : standard candle technique If a star has luminosity L (total energy emitted per sec) then at L distance D we will observe flux density F (i.e. energy per second F = 2 per sq.m. -
Arxiv:2009.03244V1 [Astro-Ph.HE] 7 Sep 2020
Advances in Understanding High-Mass X-ray Binaries with INTEGRAL and Future Directions Peter Kretschmara, Felix Furst¨ b, Lara Sidolic, Enrico Bozzod, Julia Alfonso-Garzon´ e, Arash Bodagheef, Sylvain Chatyg,h, Masha Chernyakovai,j, Carlo Ferrignod, Antonios Manousakisk,l, Ignacio Negueruelam, Konstantin Postnovn,o, Adamantia Paizisc, Pablo Reigp,q, Jose´ Joaqu´ın Rodes-Rocar,s, Sergey Tsygankovt,u, Antony J. Birdv, Matthias Bissinger ne´ Kuhnel¨ w, Pere Blayx, Isabel Caballeroy, Malcolm J. Coev, Albert Domingoe, Victor Doroshenkoz,u, Lorenzo Duccid,z, Maurizio Falangaaa, Sergei A. Grebenevu, Victoria Grinbergz, Paul Hemphillab, Ingo Kreykenbohmac,w, Sonja Kreykenbohm nee´ Fritzad,ac, Jian Liae, Alexander A. Lutovinovu, Silvia Mart´ınez-Nu´nez˜ af, J. Miguel Mas-Hessee, Nicola Masettiag,ah, Vanessa A. McBrideai,aj,ak, Andrii Neronovh,d, Katja Pottschmidtal,am,Jer´ omeˆ Rodriguezg, Patrizia Romanoan, Richard E. Rothschildao, Andrea Santangeloz, Vito Sgueraag,Rudiger¨ Staubertz, John A. Tomsickap, Jose´ Miguel Torrejon´ r,s, Diego F. Torresaq,ar, Roland Walterd,Jorn¨ Wilmsac,w, Colleen A. Wilson-Hodgeas, Shu Zhangat Abstract High mass X-ray binaries are among the brightest X-ray sources in the Milky Way, as well as in nearby Galaxies. Thanks to their highly variable emissions and complex phenomenology, they have attracted the interest of the high energy astrophysical community since the dawn of X-ray Astronomy. In more recent years, they have challenged our comprehension of physical processes in many more energy bands, ranging from the infrared to very high energies. In this review, we provide a broad but concise summary of the physical processes dominating the emission from high mass X-ray binaries across virtually the whole electromagnetic spectrum. -