2017 Observers Challenge List
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A Revised View of the Canis Major Stellar Overdensity with Decam And
MNRAS 501, 1690–1700 (2021) doi:10.1093/mnras/staa2655 Advance Access publication 2020 October 14 A revised view of the Canis Major stellar overdensity with DECam and Gaia: new evidence of a stellar warp of blue stars Downloaded from https://academic.oup.com/mnras/article/501/2/1690/5923573 by Consejo Superior de Investigaciones Cientificas (CSIC) user on 15 March 2021 Julio A. Carballo-Bello ,1‹ David Mart´ınez-Delgado,2 Jesus´ M. Corral-Santana ,3 Emilio J. Alfaro,2 Camila Navarrete,3,4 A. Katherina Vivas 5 and Marcio´ Catelan 4,6 1Instituto de Alta Investigacion,´ Universidad de Tarapaca,´ Casilla 7D, Arica, Chile 2Instituto de Astrof´ısica de Andaluc´ıa, CSIC, E-18080 Granada, Spain 3European Southern Observatory, Alonso de Cordova´ 3107, Casilla 19001, Santiago, Chile 4Millennium Institute of Astrophysics, Santiago, Chile 5Cerro Tololo Inter-American Observatory, NSF’s National Optical-Infrared Astronomy Research Laboratory, Casilla 603, La Serena, Chile 6Instituto de Astrof´ısica, Facultad de F´ısica, Pontificia Universidad Catolica´ de Chile, Av. Vicuna˜ Mackenna 4860, 782-0436 Macul, Santiago, Chile Accepted 2020 August 27. Received 2020 July 16; in original form 2020 February 24 ABSTRACT We present the Dark Energy Camera (DECam) imaging combined with Gaia Data Release 2 (DR2) data to study the Canis Major overdensity. The presence of the so-called Blue Plume stars in a low-pollution area of the colour–magnitude diagram allows us to derive the distance and proper motions of this stellar feature along the line of sight of its hypothetical core. The stellar overdensity extends on a large area of the sky at low Galactic latitudes, below the plane, and in the range 230◦ <<255◦. -
The Milky Way's Disk of Classical Satellite Galaxies in Light of Gaia
MNRAS 000,1{20 (2019) Preprint 14 November 2019 Compiled using MNRAS LATEX style file v3.0 The Milky Way's Disk of Classical Satellite Galaxies in Light of Gaia DR2 Marcel S. Pawlowski,1? and Pavel Kroupa2;3 1Leibniz-Institut fur¨ Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam, Germany 2Helmholtz-Institut fur¨ Strahlen- und Kernphysik, University of Bonn, Nussallee 14-16, D- 53115 Bonn, Germany 3Charles University in Prague, Faculty of Mathematics and Physics, Astronomical Institute, V Holeˇsoviˇck´ach 2, CZ-180 00 Praha 8, Czech Republic Accepted 2019 November 7. Received 2019 November 7; in original form 2019 August 26 ABSTRACT We study the correlation of orbital poles of the 11 classical satellite galaxies of the Milky Way, comparing results from previous proper motions with the independent data by Gaia DR2. Previous results on the degree of correlation and its significance are confirmed by the new data. A majority of the satellites co-orbit along the Vast Polar Structure, the plane (or disk) of satellite galaxies defined by their positions. The orbital planes of eight satellites align to < 20◦ with a common direction, seven even orbit in the same sense. Most also share similar specific angular momenta, though their wide distribution on the sky does not support a recent group infall or satellites- of-satellites origin. The orbital pole concentration has continuously increased as more precise proper motions were measured, as expected if the underlying distribution shows true correlation that is washed out by observational uncertainties. The orbital poles of the up to seven most correlated satellites are in fact almost as concentrated as expected for the best-possible orbital alignment achievable given the satellite posi- tions. -
Unusual Orbits in the Andromeda Galaxy Post-16
Unusual orbits in the Andromeda galaxy Post-16 Topics covered: spectra, Doppler effect, Newton’s law of gravitation, galaxy rotation curves, arc lengths, cosmological units, dark matter Teacher’s Notes In this activity students will use real scientific data to plot the rotation curve of M31 (Andromeda), our neighbouring spiral galaxy. They will use Kepler’s third law to predict the motion of stars around the centre of M31. They will then measure the wavelengths of hydrogen emission spectra taken at a range of radii. The Doppler equation will be used to determine whether these spectra come from the approaching or receding limb of the galaxy and the velocity of rotation at that point. They will plot a velocity vs radius graph and compare it with their predicted result. A flat rotation curve indicates the presence of dark matter within Andromeda. Equipment: calculator, ruler, graph paper (if needed) Questions to ask the class before the activity: What is the Universe composed of? Answer: energy, luminous matter, dark matter, dark energy. What is a spectrum and how so we get spectral lines? Answer: a ‘fingerprint’ of an object made of light. The spectrum of visible light is composed of the colours of the rainbow. Absorption lines arise from electrons absorbing photons of light and jumping an energy level or levels; emission lines occur when electrons fall down to a lower energy level and emit a photon in the process. What can a spectrum tell us? Answer: the composition of an object such as a star, its temperature, its pressure, the abundance of elements in the star, its motion (velocity). -
VI. Star-Forming Companions of Nearby Field Galaxies
A&A 486, 131–142 (2008) Astronomy DOI: 10.1051/0004-6361:20079297 & c ESO 2008 Astrophysics The Hα Galaxy Survey VI. Star-forming companions of nearby field galaxies P. A. James1, J. O’Neill2, and N. S. Shane1,3 1 Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD, UK e-mail: [email protected] 2 Wirral Grammar School for Girls, Heath Road, Bebington, Wirral CH63 3AF, UK 3 Planetary Science Group, Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK Received 20 December 2007 / Accepted 5 May 2008 ABSTRACT Aims. We searched for star-forming satellite galaxies that are close enough to their parent galaxies to be considered analogues of the Magellanic Clouds. Methods. Our search technique relied on the detection of the satellites in continuum-subtracted narrow-band Hα imaging of the central galaxies, which removes most of the background and foreground line-of-sight companions, thus giving a high probability that we are detecting true satellites. The search was performed for 119 central galaxies at distances between 20 and 40 Mpc, although spatial incompleteness means that we have effectively searched 53 full satellite-containing volumes. Results. We find only 9 “probable” star-forming satellites, around 9 different central galaxies, and 2 more “possible” satellites. After incompleteness correction, this is equivalent to 0.17/0.21 satellites per central galaxy. This frequency is unchanged whether we consider all central galaxy types or just those of Hubble types S0a–Sc, i.e. only the more luminous and massive spiral types. -
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. -
The Large Scale Universe As a Quasi Quantum White Hole
International Astronomy and Astrophysics Research Journal 3(1): 22-42, 2021; Article no.IAARJ.66092 The Large Scale Universe as a Quasi Quantum White Hole U. V. S. Seshavatharam1*, Eugene Terry Tatum2 and S. Lakshminarayana3 1Honorary Faculty, I-SERVE, Survey no-42, Hitech city, Hyderabad-84,Telangana, India. 2760 Campbell Ln. Ste 106 #161, Bowling Green, KY, USA. 3Department of Nuclear Physics, Andhra University, Visakhapatnam-03, AP, India. Authors’ contributions This work was carried out in collaboration among all authors. Author UVSS designed the study, performed the statistical analysis, wrote the protocol, and wrote the first draft of the manuscript. Authors ETT and SL managed the analyses of the study. All authors read and approved the final manuscript. Article Information Editor(s): (1) Dr. David Garrison, University of Houston-Clear Lake, USA. (2) Professor. Hadia Hassan Selim, National Research Institute of Astronomy and Geophysics, Egypt. Reviewers: (1) Abhishek Kumar Singh, Magadh University, India. (2) Mohsen Lutephy, Azad Islamic university (IAU), Iran. (3) Sie Long Kek, Universiti Tun Hussein Onn Malaysia, Malaysia. (4) N.V.Krishna Prasad, GITAM University, India. (5) Maryam Roushan, University of Mazandaran, Iran. Complete Peer review History: http://www.sdiarticle4.com/review-history/66092 Received 17 January 2021 Original Research Article Accepted 23 March 2021 Published 01 April 2021 ABSTRACT We emphasize the point that, standard model of cosmology is basically a model of classical general relativity and it seems inevitable to have a revision with reference to quantum model of cosmology. Utmost important point to be noted is that, ‘Spin’ is a basic property of quantum mechanics and ‘rotation’ is a very common experience. -
A Basic Requirement for Studying the Heavens Is Determining Where In
Abasic requirement for studying the heavens is determining where in the sky things are. To specify sky positions, astronomers have developed several coordinate systems. Each uses a coordinate grid projected on to the celestial sphere, in analogy to the geographic coordinate system used on the surface of the Earth. The coordinate systems differ only in their choice of the fundamental plane, which divides the sky into two equal hemispheres along a great circle (the fundamental plane of the geographic system is the Earth's equator) . Each coordinate system is named for its choice of fundamental plane. The equatorial coordinate system is probably the most widely used celestial coordinate system. It is also the one most closely related to the geographic coordinate system, because they use the same fun damental plane and the same poles. The projection of the Earth's equator onto the celestial sphere is called the celestial equator. Similarly, projecting the geographic poles on to the celest ial sphere defines the north and south celestial poles. However, there is an important difference between the equatorial and geographic coordinate systems: the geographic system is fixed to the Earth; it rotates as the Earth does . The equatorial system is fixed to the stars, so it appears to rotate across the sky with the stars, but of course it's really the Earth rotating under the fixed sky. The latitudinal (latitude-like) angle of the equatorial system is called declination (Dec for short) . It measures the angle of an object above or below the celestial equator. The longitud inal angle is called the right ascension (RA for short). -
Sky & Telescope
Eclipse from the See Sirius B: The Nearest Spot the Other EDGE OF SPACE p. 66 WHITE DWARF p. 30 BLUE PLANETS p. 50 THE ESSENTIAL GUIDE TO ASTRONOMY What Put the Bang in the Big Bang p. 22 Telescope Alignment Made Easy p. 64 Explore the Nearby Milky Way p. 32 How to Draw the Moon p. 54 OCTOBER 2013 Cosmic Gold Rush Racing to fi nd exploding stars p. 16 Visit SkyandTelescope.com Download Our Free SkyWeek App FC Oct2013_J.indd 1 8/2/13 2:47 PM “I can’t say when I’ve ever enjoyed owning anything more than my Tele Vue products.” — R.C, TX Tele Vue-76 Why Are Tele Vue Products So Good? Because We Aim to Please! For over 30-years we’ve created eyepieces and telescopes focusing on a singular target; deliver a cus- tomer experience “...even better than you imagined.” Eyepieces with wider, sharper fields of view so you see more at any power, Rich-field refractors with APO performance so you can enjoy Andromeda as well as Jupiter in all their splendor. Tele Vue products complement each other to pro- vide an observing experience as exquisite in performance as it is enjoyable and effortless. And how do we score with our valued customers? Judging by superlatives like: “in- credible, truly amazing, awesome, fantastic, beautiful, work of art, exceeded expectations by a mile, best quality available, WOW, outstanding, uncom- NP101 f/5.4 APO refractor promised, perfect, gorgeous” etc., BULLSEYE! See these superlatives in with 110° Ethos-SX eye- piece shown on their original warranty card context at TeleVue.com/comments. -
Facilitator Information – Galaxies
Facilitator Information (All you need to know about galaxies to survive the day) What is a galaxy? Galaxies are large collections of stars and gas and dust. They have millions to billions of stars, all held into a cluster by gravitational attraction. Most galaxies are flat, but there are different shapes — some are spirals, some are elliptical, and some are irregular. Our Galaxy The Milky Way is a galaxy, a slowly rotating cluster of more than 200,000,000,000 stars! Our Milky Way Galaxy looks a little like a pinwheel. It is a spiral galaxy, about 100,000 light years across. Spiral galaxies have: a bulge in the center (called the nuclear bulge) that contains the nucleus; a wide, flat disk with distinct spiral arms containing stars; and a surrounding halo of stars. There are several “spiral arms” in our Milky Way: Sagittarius, Cygnus, Perseus, and Orion. Where are we in the Milky Way Galaxy? We are in one of the spiral arms, about 30,000 light years from the center of the Milky Way Galaxy — or about two-thirds of the way from the center. Can you see the Milky Way? Yes! On a very dark night, away from bright lights, you can see a faint, hazy — or milky — band in the sky. This is the Milky Way. The hazy appearance is because there so many stars that are very distant; your eye cannot distinguish the stars as separate points of light. By using binoculars or a telescope, you can see the individual stars. The Milky Way is like a big, flat disk in space. -
The Andromeda Galaxy's Most Important Merger
The Andromeda Galaxy’s most important merger ~ 2 Gyrs ago as M32’s likely progenitor Richard D’Souza* & Eric F. Bell Although the Andromeda Galaxy’s (M31) proximity offers a singular opportunity to understand how mergers affect galaxies1, uncertainty remains about M31’s most important mergers. Previous studies focused individually on the giant stellar stream2 or the impact of M32 on M31’s disk3,4, thereby suggesting many significant satellite interactions5. Yet, models of M31’s disk heating6 and the similarity between the stellar populations of different tidal substructures in M31’s outskirts7 both suggested a single large merger. M31’s outer low- surface brightness regions (its stellar halo) is built up from the tidal debris of satellites5 and provides decisive guidance about its important mergers8. Here we use cosmological models of galaxy formation9,10 to show that M31’s massive11 and metal-rich12 stellar halo, containing intermediate-age stars7, dramatically narrows the range of allowed interactions, requiring a 10 single dominant merger with a large galaxy (M*~2.5x10 M¤, the third largest member of the Local Group) ~2 Gyr ago. This single event explains many observations that were previously considered separately: its compact and metal-rich satellite M3213 is likely to be the stripped core of the disrupted galaxy, M31’s rotating inner stellar halo14 contains most of the merger debris, and the giant stellar stream15 is likely to have been thrown out during the merger. This interaction may explain M31’s global burst of star formation ~2 Gyr ago16 in which ~1/5 of its stars were formed. -
Afterschool Universe Session 9 Slide Notes: Galaxies
This presentation supports the “Background” material in Session 9 of the Afterschool Universe program. This session is about galaxies. The picture shows the Whirlpool galaxy, a large, iconic, spiral galaxy. 1 Let us summarize the main concepts in this Session. We will discuss these in the rest of this presentation. 2 A galaxy is a huge collection of stars, gas and dust. A typical galaxy has about 100 billion stars (that’s 100,000,000,000 stars!), and light takes about 100,000 years to cross a galaxy (in other words, they are typically 100,000 light years ago). But some galaxies are much bigger and some are much smaller. 3 If you look at the sky from a DARK location, you can see a band of light stretching across the sky which is known as the Milky Way. This is our view of our Galaxy - more precisely, this is our view of the disk of our galaxy as seen from the INSIDE. 4 This picture shows another view of our galaxy taken in the infra-red part of the spectrum. The advantage of the infra-red is that it can penetrate the dust that pervades our galaxy’s disk and let us view the central parts of our galaxy. This picture also shows the full sky. The flat disk and central bulge of our galaxy can be seen in this picture. 5 We live in the suburbs of our galaxy. The Sun and its planetary system are about 25,000 light years from the center of the galaxy. This is about half way out to the edge of the disk. -
Corrugated Velocity Patterns in the Spiral Galaxies: NGC 278, NGC 1058, NGC 2500 & UGC 3574
Mem. S.A.It. Suppl. Vol. 25, 86 Memorie della c SAIt 2013 Supplementi Corrugated velocity patterns in the spiral galaxies: NGC 278, NGC 1058, NGC 2500 & UGC 3574 M. C. Sanchez´ Gil1, E. J. Alfaro2, and E. Perez´ 2 1 Universidad de Cadiz,´ Facultad de Ciencias Poligono Rio San Pedro 11510 - Puerto Real, Spain, e-mail: [email protected] 2 Instituto de Astrof´ısica de Andaluc´ıa (CSIC), E18008, Granada, Spain Abstract. In this work we address the study of the detection in Hα of a radial corruga- tion in the vertical velocity field in a sample of four nearly face-on, spiral galaxies. The geometry of the problem is a main criterion in the selection of the sample as well as of the azimuthal angle of the slits. These spatial corrugations must be equally associated with wavy vertical motions in the galactic plane with a strong large-scale consistency. Evidence of these kinematic waves were first detected in the analysis of the rotation curves of spiral galaxies (eg Vaucoleurs & de Vaucaleurs 1963, Pismis 1965), but it was not until 2001 that Alfaro et al. analyzed in more detail the velocity corrugations in NGC 5427 and a possi- ble physical mechanism for their origin. The aim of this study is to analyze the corrugated velocity pattern in terms of the star formation processes. We describe the geometry of the problem and establish its fundamental relationships. Key words. Techniques: spectroscopic–Galaxies: kinematics and dynamics - spiral - struc- ture 1. Introduction & Delgado 1992) and both in the azimuthal direction along different spiral arms (Spicker The disks of spiral galaxies are highly struc- & Feitzinger 1986), as in the radial, in differ- tured.