DOCSLIB.ORG

Inverse and Joint Variation 9.1.1

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Inverse and Joint Variation 9.1.1 Inverse and joint variation 9.1.1 One of the first things that scientists do with data is to graph it in various ways to see if a pattern emerges. If two variables are selected that lead to a smooth curve, the variables can be shown to lead to ‘correlated’ behavior that can either represent a direct, or inverse, variation. The specific shape of the curve indicates the exponent. The example to the left shows that for Cepheid variable stars, the Log of the star’s luminosity, L, is proportional to its period because the slope of the curve is ‘fit’ by a linear equation. Problem 1 – The radius of a black hole, R, is proportional to its mass, M, and inversely proportional to the square of the speed of light, c. If the constant of proportionality is twice Newton’s constant of gravity, G, what is the mathematical equation for the black hole radius? Problem 2 – The luminosity, L, of a star is proportional to the square of its radius, R, and proportional to its surface temperature, T, to the fourth power. What is the equation for L if the proportionality constant is C? Problem 3 – The thickness of a planetary atmosphere, H, is proportional to temperature, T, and inversely proportional to the product of its molecular mass, m, and the local acceleration of gravity, g. What is the equation for H if the constant of proportionality is k? Problem 4 – The temperature of a planet, T, to the fourth power is proportional to the luminosity, L, of the star that it orbits, and inversely proportional to the square of its distance from its star, D. If the proportionality constant is (1-A) where A is a constant indicating the reflectivity of the planet, what is the equation for the temperature? Space Math http://spacemath.gsfc.nasa.gov Answer Key 9.1.1 Problem 1 – The radius of a black hole, R, is proportional to its mass, M, and inversely proportional to the square of the speed of light, c. If the constant of proportionality is twice Newton’s constant of gravity, G, what is the equation for the black hole radius? 2GM Answer: R c2 Problem 2 – The luminosity, L, of a star is proportional to the square of its radius, R, and proportional to its surface temperature, T, to the fourth power. What is the equation for L if the proportionality constant is C? Answer: LCRT 24 Problem 3 – The thickness of a planetary atmosphere, H, is proportional to temperature, T, and inversely proportional to the product of its molecular mass, m, and the local acceleration of gravity, g. What is the equation for H if the constant of proportionality is k? T Answer: Hk mg Problem 4 – The temperature of a planet, T, to the fourth power is proportional to the luminosity, L, of the star that it orbits, and inversely proportional to the square of its distance from its star, D. If the proportionality constant is (1-A) where A is a constant indicating the reflectivity of the planet, what is the equation for the temperature? (1 A ) L Answer: T 4 D2 Space Math http://spacemath.gsfc.nasa.gov Inverse and joint variation 9.1.2 Since 1800, scientists have measured the average sea level using a variety of independent methods including hundreds of tide gauges and satellite data. The table below gives the average sea level change since 1910 based upon research published by the International Commission on Global Climate Change (2007) Year Height Year Height (cm) (cm) 1910 +1 1960 +11 1920 +2 1970 +12 1930 +4 1980 +13 1940 +5 1990 +14 1950 +7 2000 +18 Problem 1 – State whether there is a direct correlation, an inverse correlation or no correlation between the year and the average sea height change since 1910. Problem 2 – What is the mathematical formula that models the general behavior of the data in this table? Problem 3 - Assuming that the underlying physical conditions remain the same, and your model holds true, for a doubling of the period since 1910, what does your model predict for the sea level change in A) 2020? B) 2050? C) 2100? Space Math http://spacemath.gsfc.nasa.gov Answer Key 9.1.2 Problem 1 – State whether there is a direct correlation, an inverse correlation or no correlation between the year and the average sea height change since 1880. Answer: Students may graph the data to visually determine the trend. From the table, they should notice that, as the year increases, so too does the sea level change, indicating a direct, rather than inverse, correlation. Problem 2 – What is the mathematical formula that models the general behavior of the data in this table? Answer: Students may use a variety of methods for ‘fitting’ the data. Since a direct correlation is of the form H = cY where H is the height in centimeters and Y is the number of years since 1910, selecting a point in the middle of the range, (1950, +7), leads to +7 = c (1950-1910) so c = 7/40 =0.175 and so H = 0.175Y. Problem 3 - Assuming that the underlying physical conditions remain the same, and your model holds true, for a doubling of the period since 1880, what does your model predict for the sea level change in A) 2020? B) 2050? C) 2100? Answer: A) H(2020) = 0.175(2020-1910) = +19 centimeters; B) H(2050) = 0.175(2050-1910) = +24 centimeters; C) H(2100) = 0.175(2100-1910) = +33 centimeters; Actual sea level change data from ICGCC report. Space Math http://spacemath.gsfc.nasa.gov Graphing Simple Rational Functions 9.2.1 In 2008, the Hubble and Spitzer Space Telescopes identified one of the farthest galaxies from our Milky Way. It is so distant that light has taken over 12.9 billion years to reach Earth, showing us what this galaxy looked like 12.9 billion years ago. The actual distance to this galaxy today is approximately given by the following formula: 877zz 7 7 Dz() 1 (1 z ) 8 8 8 4 The distance, D, is defined in units of billions of light years so that ‘D = 10’ means 10 billion light years. The quantity z is called the redshift of the galaxy. It can easily be measured by analyzing the light from the galaxy and is defined by the domain Z:[0,+infinity] Top image shows where the galaxy A1689-zD1 was found. Bottom image shows the galaxy at the center of the field studied by the Hubble Space Telescope. Problem 1 – Graph the function D(z) over the domain Z: [0,+10]. Problem 2 - The most distant known galaxy identified in 2008 is called A1689- zD1. The data from the Hubble Space Telescope indicated a redshift of z = 7.6. How far from Earth is this galaxy in terms of billions of light years? Problem 3 - An astronomer is studying two pairs of galaxies, A,B, and C, D, located in the Hubble Deep Field. He measures the redshifts to each galaxy and determines that Z(A) = 1.5, Z(B) = 2.5 and that Z(C) = 5.5 and Z(D) = 6.5. Which pair of galaxies have members that appear to be the closest together in actual distance, D? Space Math http://spacemath.gsfc.nasa.gov Answer Key 9.2.1 Problem 1 – Graph the function D(z) over the domain Z: [0,+10]. 45.0 40.0 35.0 30.0 25.0 D(z) 20.0 15.0 10.0 5.0 0.0 0246810 Z Problem 2 - The most distant known galaxy identified in 2008 is called A1689-zD1. The data from the Hubble Space Telescope indicated a redshift of z = 7.6. How far from Earth is this galaxy in terms of billions of light years? Answer: 1/2 D(7.6) = 877 [7.6/8 + 7/8 – 7/8(7.6/4 +1) )]/(1+7.6) = 877 [0.95 +0.875 – 0.875(1.70)]/8.6 = 877 (0.335)/8.6 = 34.2 billion light years. Problem 3 - An astronomer is studying two pairs of galaxies, A,B, and C, D, located in the Hubble Deep Field. He measures the redshifts to each galaxy and determines that Z(A) = 1.5, Z(B) = 1.6 and that Z(C) = 7.5 and Z(D) = 7.6. Which pair of galaxies have members that appear to be the closest together in actual distance, D? Answer: D(A) = 12.8 billion light years D(B) = 13.4 billion light years D(C) = 33.9 billion light years D(D) = 34.2 billion light years The pair of galaxies C and D are closer together (34.2 – 33.9 = 0.3 billion light years) than galaxies A and B which are 13.4 – 12.8 = 0.6 billion light years apart. Note: The equation for D(z) does not include additional cosmological factors that will change the answers downward by about 10%. Space Math http://spacemath.gsfc.nasa.gov Graphing Simple Rational Functions 9.2.2 When a source of light moves relative to an observer, the frequency of the light waves will be increased if the movement is towards the observer, or decreased if the motion is away from the observer. This phenomenon is called the Doppler Effect, and it is given by the formula: c ff s cV where V is the speed of the source, fs is the normal frequency of the light seen by The rotating sun causes a Doppler Effect.
Load more

Recommended publications
  • Structure and Kinematics of the Virgo Cluster of Galaxies? Olga G
    A&A 635, A135 (2020) Astronomy https://doi.org/10.1051/0004-6361/201936172 & c ESO 2020 Astrophysics Structure and kinematics of the Virgo cluster of galaxies? Olga G. Kashibadze1;??, Igor D. Karachentsev1, and Valentina E. Karachentseva2 1 Special Astrophysical Observatory of the Russian Academy of Sciences, Nizhnij Arkhyz, Karachay-Cherkessia 369167, Russia e-mail: [email protected] 2 Main Astronomical Observatory of the National Academy of Sciences, 27 Akademika Zabolotnoho St., Kyiv 03143, Ukraine Received 25 June 2019 / Accepted 24 January 2020 ABSTRACT Aims. This work considers the Virgo cluster of galaxies, focusing on its structure, kinematics, and morphological landscape. Our principal aim is to estimate the virial mass of the cluster. For this purpose, we present a sample of 1537 galaxies with radial velocities −1 ◦ ◦ VLG < 2600 km s situated within a region of ∆SGL = 30 and ∆SGB = 20 around M 87. About half of the galaxies have distance estimates. Methods. We selected 398 galaxies with distances in a (17 ± 5) Mpc range. Based on their 1D and 2D number-density profiles and their radial velocity dispersions, we made an estimate for the virial mass of the Virgo cluster. Results. We identify the infall of galaxies towards the Virgo cluster core along the Virgo Southern Extension filament. From a 1D 14 profile of the cluster, we obtain the virial mass estimate of (6:3 ± 0:9) × 10 M , which is in tight agreement with its mass estimate via the external infall pattern of galaxies. Conclusions. We conclude that the Virgo cluster outskirts between the virial radius and the zero-velocity radius do not contain significant amounts of dark matter beyond the virial radius.
    [Show full text]
  • SMG20 - Twenty Years of Submillimetre Galaxies Star-Forming Galaxies at High Redshifts 31St July – 2Nd August 2017
    SMG20 - Twenty years of Submillimetre Galaxies Star-forming galaxies at high redshifts 31st July – 2nd August 2017 Monday 31th July Session 1 Loretta Dunne “Results from Herschel on galaxy formation and evolution” Cardiff Review talk covering results from Herschel on galaxy formation and evolution. James Geach “The SCUBA-2 Cosmology Legacy Survey and beyond” University of Hertfordshire The SCUBA-2 Cosmology Legacy Survey (S2CLS) is the largest 850 mm survey to date, detecting 1000’s of sub-mm sources over about 5 square degrees and providing exceptionally deep 450+850 mm maps in several extragalactic fields. It is enabling detailed studies of the SMG population and feeds directly into ALMA follow-up programmes. Now complete, I will present an overview of S2CLS and highlight some of the key science results so far. I will conclude with a look to the future of large ground-based sub-mm surveys, in particular what could be achieved with a new large single dish located on the Chajnantor Plateau. SMG20 31st July - 2nd August 2017 2 Scott Chapman “Identifying the brightest galaxies in the SCUBA-2 Cosmology Legacy Survey” Dalhousie University Using the SMA and complemented by ALMA in the UDS, we have identified the 120 brightest SCUBA-2 sources in the SCUBA-2 Cosmology Legacy Survey. This consists of all sources with S850mm > 9 mJy, and includes several unlensed sources with single component fluxes close to 20 mJy. Previous studies have had little sta- tistical constraint on the true bright end count, and therefore on the properties of these maximal star formers. Spectroscopic surveys with Keck, Gemini, and VLT have measured redshifts and line properties for about 30% of these sources.
    [Show full text]
  • Atomic Gas Far Away from the Virgo Cluster Core Galaxy NGC 4388
    Astronomy & Astrophysics manuscript no. H4396 November 5, 2018 (DOI: will be inserted by hand later) Atomic gas far away from the Virgo cluster core galaxy NGC 4388 A possible link to isolated star formation in the Virgo cluster? B. Vollmer, W. Huchtmeier Max-Planck-Institut f¨ur Radioastronomie, Auf dem H¨ugel 69, D-53121 Bonn, Germany Received / Accepted 7 ′ Abstract. We have discovered 6 10 M⊙ of atomic gas at a projected distance greater than 4 (20 kpc) from the highly inclined Virgo spiral galaxy NGC 4388. This gas is most probably connected to the very extended Hα plume detected by Yoshida et al. (2002). Its mass makes a nuclear outflow and its radial velocity a minor merger as the origin of the atomic and ionized gas very unlikely. A numerical ram pressure simulation can account for the observed Hi spectrum and the morphology of the Hα plume. An additional outflow mechanism is still needed to reproduce the velocity field of the inner Hα plume. The extraplanar compact Hii region recently found by Gerhard et al. (2002) can be explained as a stripped gas cloud that collapsed and decoupled from the ram pressure wind due to its increased surface density. The star-forming cloud is now falling back onto the galaxy. Key words. Galaxies: individual: NGC 4388 – Galaxies: interactions – Galaxies: ISM – Galaxies: kinematics and dynamics 1. Introduction stripping. Based on their data they favoured a combina- tion of (iii) and (iv). Yoshida et al. (2002) on the other The Virgo cluster spiral galaxy NGC 4388 is located at hand favoured scenario (i) and (iv).
    [Show full text]
  • Messier Objects
    Messier Objects From the Stocker Astroscience Center at Florida International University Miami Florida The Messier Project Main contributors: • Daniel Puentes • Steven Revesz • Bobby Martinez Charles Messier • Gabriel Salazar • Riya Gandhi • Dr. James Webb – Director, Stocker Astroscience center • All images reduced and combined using MIRA image processing software. (Mirametrics) What are Messier Objects? • Messier objects are a list of astronomical sources compiled by Charles Messier, an 18th and early 19th century astronomer. He created a list of distracting objects to avoid while comet hunting. This list now contains over 110 objects, many of which are the most famous astronomical bodies known. The list contains planetary nebula, star clusters, and other galaxies. - Bobby Martinez The Telescope The telescope used to take these images is an Astronomical Consultants and Equipment (ACE) 24- inch (0.61-meter) Ritchey-Chretien reflecting telescope. It has a focal ratio of F6.2 and is supported on a structure independent of the building that houses it. It is equipped with a Finger Lakes 1kx1k CCD camera cooled to -30o C at the Cassegrain focus. It is equipped with dual filter wheels, the first containing UBVRI scientific filters and the second RGBL color filters. Messier 1 Found 6,500 light years away in the constellation of Taurus, the Crab Nebula (known as M1) is a supernova remnant. The original supernova that formed the crab nebula was observed by Chinese, Japanese and Arab astronomers in 1054 AD as an incredibly bright “Guest star” which was visible for over twenty-two months. The supernova that produced the Crab Nebula is thought to have been an evolved star roughly ten times more massive than the Sun.
    [Show full text]
  • Downloading Rectification Matrices the first Step Will Be Downloading the Correct Rectification Matrix for Your Data Off of the OSIRIS Website
    UNDERGRADUATE HONORS THESIS ADAPTIVE-OPTICS INTEGRAL-FIELD SPECTROSCOPY OF NGC 4388 Defended October 28, 2016 Skylar Shaver Thesis Advisor: Dr. Julie Comerford, Astronomy Honor Council Representative: Dr. Erica Ellingson, Astronomy Committee Members: Dr. Francisco Müller-Sánchez, Astrophysics Petger Schaberg, Writing Abstract Nature’s most powerful objects are well-fed supermassive black holes at the centers of galaxies known as active galactic nuclei (AGN). Weighing up to billions of times the mass of our sun, they are the most luminous sources in the Universe. The discovery of a number of black hole-galaxy relations has shown that the growth of supermassive black holes is closely related to the evolution of galaxies. This evidence has opened a new debate in which the fundamental questions concern the interactions between the central black hole and the interstellar medium within the host galaxy and can be addressed by studying two crucial processes: feeding and feedback. Due to the nature of AGN, high spatial resolution observations are needed to study their properties in detail. We have acquired near infrared Keck/OSIRIS adaptive optics-assisted integral field spectroscopy data on 40 nearby AGN as part of a large program aimed at studying the relevant physical processes associated with AGN phenomenon. This program is called the Keck/OSIRIS nearby AGN survey (KONA). We present here the analysis of the spatial distribution and two-dimensional kinematics of the molecular and ionized gas in NGC 4388. This nearly edge-on galaxy harbors an active nucleus and exhibits signs of the feeding and feedback processes. NGC 4388 is located in the heart of the Virgo cluster and thus is subject to possible interactions with the intra-cluster medium and other galaxies.
    [Show full text]
  • Detection of Intergalactic Red-Giant-Branch Stars in the Virgo Cluster
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Embry-Riddle Aeronautical University Publications Summer 8-28-1998 Detection of Intergalactic Red-Giant-Branch Stars in the Virgo Cluster Henry C. Ferguson Space Telescope Science Institute, [email protected] Ted von Hippel University of Wisconsin, [email protected] Nial R. Tanvir University of Cambridge, [email protected] Follow this and additional works at: https://commons.erau.edu/publication Part of the Stars, Interstellar Medium and the Galaxy Commons Scholarly Commons Citation Ferguson, H. C., von Hippel, T., & Tanvir, N. R. (1998). Detection of Intergalactic Red-Giant-Branch Stars in the Virgo Cluster. Nature, 391(). https://doi.org/10.1038/35087 This Article is brought to you for free and open access by Scholarly Commons. It has been accepted for inclusion in Publications by an authorized administrator of Scholarly Commons. For more information, please contact [email protected]. Detection of Intergalactic Red Giant Branch Stars in the Virgo Cluster Henry C. Ferguson Space Telescope Science Institute, Baltimore, MD 21218, USA [email protected] Nial R. Tanvir University of Cambridge, Institute of Astronomy Madingley Road, Cambridge CB3 0HA, UK [email protected] Ted von Hippel Department of Astronomy, University of Wisconsin Address: WIYN Telescope, NOAO, PO Box 26732, Tucson, AZ 85726, USA [email protected] August 28, 2018 It has been suspected for nearly 50 years that clusters of galax- ies contain a population of intergalactic stars, ripped from galaxies during cluster formation or when the galaxies’ orbits take them through the cluster center.1, 2, 3 Support for the existence of such a population of free-floating stars comes from measurements of the diffuse light in clusters 4, 5, 6, 7, 8, 9, and from recent detections of planetary nebulae with positions and/or velocities far removed from any observed cluster galaxy.
    [Show full text]
  • Spring Constellations Leo
    Night Sky 101: Spring Constellations Leo Leo, the lion, is very recognizable by the head of the lion, which looks like a backwards question mark, and is commonly known as “the sickle.” Regulus, Leo’s brightest star, is also easy to pick out in most lights. The constellation is best seen in April and May, but rises after the Spring Equinox in March. Within the constellation, there are several spiral galaxies: M65, M66, M95, and M96. It is possible to fit M65 and M66 into the same view on a low powered telescope. In Greek mythology, Leo was the Nemean lion, who was completely impervious to bronze, steel and any kind of metal. As part of his 12 labors, Hercules was charged to fight the lion and killed him Photo Credit: Starry Night by strangling him. Hercules took the lion’s pelt as a prize and Leo, the lion, was placed in the stars to commemorate their fight. Virgo Virgo is best seen in the late spring and early summer, usually May to June. The bright star Arcturus, in the constellation Boötes, lines up with the Virgo’s brightest star Spica, which makes it easy to find. Within the constellation is the Virgo Galaxy Cluster, which is a conglomerate of thousands of unnamed galaxies. These galaxies are about 65 million light years away, and usually only appear as smudges in a telescope. Virgo, the maiden, is also known as Persephone, or the daughter of the Demeter. Hades, god of the Un- derworld, fell in love with Virgo and took her to the Underworld.
    [Show full text]
  • 18. Mapping the Universe the Local Group: Over 30 Galaxies
    Astronomy 242: Foundations of Astrophysics II 18. Mapping the Universe The Local Group: Over 30 Galaxies two large spirals with satellites one smaller spiral many dwarf elliptical and irregular galaxies Local Group The M81 Group M81 and M82 deep field The M81 Group in HI Tidal dwarfs in the M81 group The M81 Group M81 and M82 deep field The Virgo Cluster:: Over 1000 Galaxies! Distance: ~16 Mpc three massive elliptical galaxies many MW-sized galaxies The Virgo Cluster Abell 1689 Distance: ~754 Mpc Abell 1689: A Galaxy Cluster Makes Its Mark Abell 1689 in X-rays 7 keV Fe line (redshifted) X-ray Spectrum Abell 1689: A Galaxy Cluster Makes Its Mark Abell 1689 Central Galaxy Abell 1689: A Galaxy Cluster Makes Its Mark Abell 1689 Lensed galaxy in background Abell 1689: A Galaxy Cluster Makes Its Mark The Super-Galactic Plane Cosmography of the Local Universe Local Cosmography Pavo-Indus Super-Galactic Plane Perseus-Pisces Virgo Cluster 0 4000 8000 vr (km/s) Fornax Cluster Cosmography of the Local Universe The 2MASS Redshift Survey RESEARCH LETTER Extended Data Figure 3 | One of three orthogonal views that illustrate SGY 5 0 showing the region obscured by the plane of the Milky Way. As in the limits of the Laniakea supercluster. This SGX–SGY view at SGZ 5 0 Fig 2 in the main text, the orange contour encloses the inflowing streams, extends the scene shown in Fig. 2 with the addition of dark blue flow lines away hence, defines the limits of the LaniakeaThe Laniakea Supercluster supercluster of Galaxies containing the mass of from the Laniakea local basin of attraction, and also includes a dark swath at 1017 Suns and 100,000 large galaxies.
    [Show full text]
  • Messier 58, 59, 60, 89, and 90, Galaxies in Virgo
    Messier 58, 59, 60, 89, and 90, Galaxies in Virgo These are five of the many galaxies of the Coma-Virgo galaxy cluster, a prime hunting ground for galaxy observers every spring. Dozens of galaxies in this cluster are visible in medium to large amateur telescopes. This star hop includes elliptical galaxies M59, M60, and M89, and spiral galaxies M58 and M90. These galaxies are roughly 50 to 60 million light years away. All of them are around magnitude 10, and should be visible in even a small telescope. Start by finding the Spring Triangle, which consists of three widely- separated first magnitude stars-- Arcturus, Spica, and Regulus. The Spring Triangle is high in the southeast sky in early spring, and in the southwest sky by mid-Summer. (To get oriented, you can use the handle of the Big Dipper and "follow the arc to Arcturus"). For this star hop, look in the middle of the Spring Triangle for Denebola, the star representing the back end of Leo, the lion, and Vindemiatrix, a magnitude 2.8 star in Virgo. The galaxies of the Virgo cluster are found in the area between these two stars. From Vindemiatrix, look 5 degrees west and slightly south to find ρ (rho) Virginis, a magnitude 4.8 star that is easy to identify because it is paired with a slightly dimmer star just to its north. Center ρ in the telescope with a low-power eyepiece, and then just move 1.4 degrees north to arrive at the oval shape of M59. Continuing with a low-power eyepiece and using the chart below, you can take hops of less than 1 degree to find M60 to the east of M59, and M58, M89, and M90 to the west and north.
    [Show full text]
  • General Disclaimer One Or More of the Following Statements May Affect This Document
    General Disclaimer One or more of the Following Statements may affect this Document This document has been reproduced from the best copy furnished by the organizational source. It is being released in the interest of making available as much information as possible. This document may contain data, which exceeds the sheet parameters. It was furnished in this condition by the organizational source and is the best copy available. This document may contain tone-on-tone or color graphs, charts and/or pictures, which have been reproduced in black and white. This document is paginated as submitted by the original source. Portions of this document are not fully legible due to the historical nature of some of the material. However, it is the best reproduction available from the original submission. Produced by the NASA Center for Aerospace Information (CASI) N79-28092 (NASA-T"1-80294) A SEARCH FOR X-RAY FM13STON FROM RICH CLUSTF.'+S, F.XTFNt1Et'• F1ALOS AWIND CLUSTERS, AND SUPERCLUSTERS (NASA) 37 p rinclas HC AOl/ N F A01 CSCL 038 G3/90 29952 Technical Memorandum 80294 A Search for X- Ray Emission from Riche Clusters, Extended Halos around Clusters, and Superclusters S. H. Pravdo, E. A. Boldt, F. E. Marshall, J. Mc Kee, R. F. Mushotzky, B. W. Smith, and G. Reichert JUNE 1979 A Naticnal Aeronautics and Snn,^ Administration "` Goddard Space Flight Center Greenbelt, Maryland 20771 A SEARCH FOR X-RAY EMISSION FROM RICH CLUSTERS, EXTENDED HALOS AROUND CLUSTERS, ANU SUPERCLUSTERS • S.H Pravdo E A Boldt, F.E Marshall J. McKee R.F Mushotzky , B.W.
    [Show full text]
  • Virgo the Virgin
    Virgo the Virgin Virgo is one of the constellations of the zodiac, the group tion Virgo itself. There is also the connection here with of 12 constellations that lies on the ecliptic plane defined “The Scales of Justice” and the sign Libra which lies next by the planets orbital orientation around the Sun. Virgo is to Virgo in the Zodiac. The study of astronomy had a one of the original 48 constellations charted by Ptolemy. practical “time keeping” aspect in the cultures of ancient It is the largest constellation of the Zodiac and the sec- history and as the stars of Virgo appeared before sunrise ond - largest constellation after Hydra. Virgo is bordered by late in the northern summer, many cultures linked this the constellations of Bootes, Coma Berenices, Leo, Crater, asterism with crops, harvest and fecundity. Corvus, Hydra, Libra and Serpens Caput. The constella- tion of Virgo is highly populated with galaxies and there Virgo is usually depicted with angel - like wings, with an are several galaxy clusters located within its boundaries, ear of wheat in her left hand, marked by the bright star each of which is home to hundreds or even thousands of Spica, which is Latin for “ear of grain”, and a tall blade of galaxies. The accepted abbreviation when enumerating grass, or a palm frond, in her right hand. Spica will be objects within the constellation is Vir, the genitive form is important for us in navigating Virgo in the modern night Virginis and meteor showers that appear to originate from sky. Spica was most likely the star that helped the Greek Virgo are called Virginids.
    [Show full text]
  • Angular Momentum of Galaxies in the Densest Environments: a FLAMES/GIRAFFE IFS Study of the Massive Cluster Abell 1689 at Z = 0
    Astronomical Science Angular Momentum of Galaxies in the Densest Environments: A FLAMES/GIRAFFE IFS Study of the Massive Cluster Abell 1689 at z = 0.18 Francesco D’Eugenio1 of these empirical laws — alongside their bined with the collecting power of the Ryan C. W. Houghton1 very small scatter — imposes strong ESO Very Large Telescope (VLT), are the Roger L. Davies1 constraints on the structure and evolution ideal tools for this task. Elena Dalla Bontà2, 3 of ETGs (Bower et al., 1992). This makes them ideal testing grounds for any galaxy formation theory. Their study, important FLAMES/GIRAFFE observations of 1 Sub-department of Astrophysics, in its own right, is also fundamental Abell 1689 Department of Physics, University of for our understanding of the process of Oxford, United Kingdom structure formation in the Universe. Abell 1689, a massive galaxy cluster at 2 Dipartimento di Fisica e Astronomia redshift z = 0.183, has regular, concen- “G. Galilei”, Università degli Studi di The advent of integral field spectroscopy tric X-ray contours suggesting that it Padova, Italy (IFS) started a revolution in the study of is re laxed. Its X-ray luminosity outshines 3 INAF–Osservatorio Astronomico di ETGs. The SAURON survey discovered Coma by a factor of three, and Virgo Padova, Italy the existence of two kinematically distinct by over an order of magnitude. Its comov- classes of ETGs, slow and fast rotators ing distance is 740 Mpc, giving a scale (SRs and FRs, see Emsellem et al. [2007]) of 1 arcsecond per 3.0 kpc. Alongside its Early-type galaxies (ETGs) exhibit kine- and Cappellari et al.
    [Show full text]