Newtonian Explanation of Galaxy Rotation Curves Based on Distribution of Baryonic Matter Konstantin Pavlovich, Alex Pavlovich & Alan Sipols June 9, 2014
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(Dark) Matter! Luminous Matter Is Concentrated at the Center
Cosmology Two Mysteries and then How we got here Dark Matter Orbital velocity law Derivable from Kepler's 3rd law and Newton's Law of gravity r v2 M = r G M : mass lying within stellar orbit r r: radius from the Galactic center v: orbital velocity From Sun's r and v: there are about 100 billion solar masses inside the Sun's orbit! 4 Rotation curve of the Milky Way: Speed of stars and clouds of gas (from Doppler shift) vs distance from center Galaxy: rotation curve flattens out with distance Indicates much more mass in the Galaxy than observed as stars and gas! Mass not concentrated at center5 From the rotation curve, inferred distribution of dark matter: The Milky Way is surrounded by an enormous halo of non-luminous (dark) matter! Luminous matter is concentrated at the center 6 We can make measurements for other galaxies Weighing spiral galaxies C Compare shifts of spectral lines (in atomic H gas clouds) as a function of distance from the center 7 Rotation curves for various spiral galaxies First measured in 1960's by Vera Rubin They all flatten out with increasing radius, implying that all spiral galaxies have vast haloes of dark matter – luminous matter 1/6th of mass 8 This mass is the DARK MATTER: It's some substance that interacts gravitationally (equivalent to saying that it has mass)... It neither emits nor absorbs light in any form (equivalent to saying that it does not interact electromagnetically) Dark matter might conceivably have 'weak' (radioactive force) interactions 9 Gaggles of Galaxies • Galaxy groups > The Local group -
April Constellations of the Month
April Constellations of the Month Leo Small Scope Objects: Name R.A. Decl. Details M65! A large, bright Sa/Sb spiral galaxy. 7.8 x 1.6 arc minutes, magnitude 10.2. Very 11hr 18.9m +13° 05’ (NGC 3623) high surface brighness showing good detail in medium sized ‘scopes. M66! Another bright Sb galaxy, only 21 arc minutes from M65. Slightly brighter at mag. 11hr 20.2m +12° 59’ (NGC 3627) 9.7, measuring 8.0 x 2.5 arc minutes. M95 An easy SBb barred spiral, 4 x 3 arc minutes in size. Magnitude 10.5, with 10hr 44.0m +11° 42’ a bright central core. The bar and outer ring of material will require larger (NGC 3351) aperature and dark skies. M96 Another bright Sb spiral, about 42 arc minutes east of M95, but larger and 10hr 46.8m +11° 49’ (NGC 3368) brighter. 6 x 4 arc minutes, magnitude 10.1. Located about 48 arc minutes NNE of M96. This small elliptical galaxy measures M105 only 2 x 2.1 arc minutes, but at mag. 10.3 has very high surface brightness. 10hr 47.8m +12° 35’ (NGC 3379) Look for NGC 3384! (110NGC) and NGC 3389 (mag 11.0 and 12.2) which form a small triangle with M105. NGC 3384! 10hr 48.3m +12° 38’ See comment for M105. The brightest galaxy in Leo, this Sb/Sc spiral galaxy shines at mag. 9.5. Look for NGC 2903!! 09hr 32.2m +21° 30’ a hazy patch 11 x 4.7 arc minutes in size 1.5° south of l Leonis. -
A Case for Alternate Theories of Gravity C Sivaram Indian Institute Of
Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 19 June 2020 doi:10.20944/preprints202006.0239.v1 Non-detection of Dark Matter particles: A case for alternate theories of gravity C Sivaram Indian Institute of Astrophysics, Bangalore, 560 034, India e-mail: [email protected] Kenath Arun Christ Junior College, Bangalore, 560 029, India e-mail: [email protected] A Prasad Center for Space Plasma & Aeronomic Research, The University of Alabama in Huntsville, Huntsville, Alabama 35899 email: [email protected] Louise Rebecca Christ Junior College, Bangalore - 560 029, India e-mail: [email protected] Abstract: While there is overwhelming evidence for dark matter (DM) in galaxies and galaxy clusters, all searches for DM particles have so far proved negative. It is not even clear whether only one particle is involved or a combination or particles, their masses not precisely predicted. This non-detectability raises the possible relevance of modified gravity theories – MOND, MONG, etc. Here we consider a specific modification of Newtonian gravity (MONG) which involves gravitational self-energy, leading to modified equations whose solutions imply flat rotation curves and limitations of sizes of clusters. The results are consistent with current observations including that involving large spirals. This modification could also explain the current Hubble tension. We also consider effects of dark energy (DE) in terms of a cosmological constant. 1 © 2020 by the author(s). Distributed under a Creative Commons CC BY license. Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 19 June 2020 doi:10.20944/preprints202006.0239.v1 Over the past few decades there have been a plethora of sophisticated experiments involving massive sensitive detectors trying to catch faint traces of the elusive Dark Matter (DM) particles. -
Disk Galaxy Rotation Curves and Dark Matter Distribution
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server Disk galaxy rotation curves and dark matter distribution by Dilip G. Banhatti School of Physics, Madurai-Kamaraj University, Madurai 625021, India [Based on a pedagogic / didactic seminar given by DGB at the Graduate College “High Energy & Particle Astrophysics” at Karlsruhe in Germany on Friday the 20 th January 2006] Abstract . After explaining the motivation for this article, we briefly recapitulate the methods used to determine the rotation curves of our Galaxy and other spiral galaxies in their outer parts, and the results of applying these methods. We then present the essential Newtonian theory of (disk) galaxy rotation curves. The next two sections present two numerical simulation schemes and brief results. Finally, attempts to apply Einsteinian general relativity to the dynamics are described. The article ends with a summary and prospects for further work in this area. Recent observations and models of the very inner central parts of galaxian rotation curves are omitted, as also attempts to apply modified Newtonian dynamics to the outer parts. Motivation . Extensive radio observations determined the detailed rotation curve of our Milky Way Galaxy as well as other (spiral) disk galaxies to be flat much beyond their extent as seen in the optical band. Assuming a balance between the gravitational and centrifugal forces within Newtonian mechanics, the orbital speed V is expected to fall with the galactocentric distance r as V 2 = GM/r beyond the physical extent of the galaxy of mass M, G being the gravitational constant. -
SAC's 110 Best of the NGC
SAC's 110 Best of the NGC by Paul Dickson Version: 1.4 | March 26, 1997 Copyright °c 1996, by Paul Dickson. All rights reserved If you purchased this book from Paul Dickson directly, please ignore this form. I already have most of this information. Why Should You Register This Book? Please register your copy of this book. I have done two book, SAC's 110 Best of the NGC and the Messier Logbook. In the works for late 1997 is a four volume set for the Herschel 400. q I am a beginner and I bought this book to get start with deep-sky observing. q I am an intermediate observer. I bought this book to observe these objects again. q I am an advance observer. I bought this book to add to my collect and/or re-observe these objects again. The book I'm registering is: q SAC's 110 Best of the NGC q Messier Logbook q I would like to purchase a copy of Herschel 400 book when it becomes available. Club Name: __________________________________________ Your Name: __________________________________________ Address: ____________________________________________ City: __________________ State: ____ Zip Code: _________ Mail this to: or E-mail it to: Paul Dickson 7714 N 36th Ave [email protected] Phoenix, AZ 85051-6401 After Observing the Messier Catalog, Try this Observing List: SAC's 110 Best of the NGC [email protected] http://www.seds.org/pub/info/newsletters/sacnews/html/sac.110.best.ngc.html SAC's 110 Best of the NGC is an observing list of some of the best objects after those in the Messier Catalog. -
00E the Construction of the Universe Symphony
The basic construction of the Universe Symphony. There are 30 asterisms (Suites) in the Universe Symphony. I divided the asterisms into 15 groups. The asterisms in the same group, lay close to each other. Asterisms!! in Constellation!Stars!Objects nearby 01 The W!!!Cassiopeia!!Segin !!!!!!!Ruchbah !!!!!!!Marj !!!!!!!Schedar !!!!!!!Caph !!!!!!!!!Sailboat Cluster !!!!!!!!!Gamma Cassiopeia Nebula !!!!!!!!!NGC 129 !!!!!!!!!M 103 !!!!!!!!!NGC 637 !!!!!!!!!NGC 654 !!!!!!!!!NGC 659 !!!!!!!!!PacMan Nebula !!!!!!!!!Owl Cluster !!!!!!!!!NGC 663 Asterisms!! in Constellation!Stars!!Objects nearby 02 Northern Fly!!Aries!!!41 Arietis !!!!!!!39 Arietis!!! !!!!!!!35 Arietis !!!!!!!!!!NGC 1056 02 Whale’s Head!!Cetus!! ! Menkar !!!!!!!Lambda Ceti! !!!!!!!Mu Ceti !!!!!!!Xi2 Ceti !!!!!!!Kaffalijidhma !!!!!!!!!!IC 302 !!!!!!!!!!NGC 990 !!!!!!!!!!NGC 1024 !!!!!!!!!!NGC 1026 !!!!!!!!!!NGC 1070 !!!!!!!!!!NGC 1085 !!!!!!!!!!NGC 1107 !!!!!!!!!!NGC 1137 !!!!!!!!!!NGC 1143 !!!!!!!!!!NGC 1144 !!!!!!!!!!NGC 1153 Asterisms!! in Constellation Stars!!Objects nearby 03 Hyades!!!Taurus! Aldebaran !!!!!! Theta 2 Tauri !!!!!! Gamma Tauri !!!!!! Delta 1 Tauri !!!!!! Epsilon Tauri !!!!!!!!!Struve’s Lost Nebula !!!!!!!!!Hind’s Variable Nebula !!!!!!!!!IC 374 03 Kids!!!Auriga! Almaaz !!!!!! Hoedus II !!!!!! Hoedus I !!!!!!!!!The Kite Cluster !!!!!!!!!IC 397 03 Pleiades!! ! Taurus! Pleione (Seven Sisters)!! ! ! Atlas !!!!!! Alcyone !!!!!! Merope !!!!!! Electra !!!!!! Celaeno !!!!!! Taygeta !!!!!! Asterope !!!!!! Maia !!!!!!!!!Maia Nebula !!!!!!!!!Merope Nebula !!!!!!!!!Merope -
High-Resolution Measurements of the Halos of Four Dark Matter
Accepted for publication in The Astrophysical Journal A Preprint typeset using LTEX style emulateapj v. 6/22/04 HIGH-RESOLUTION MEASUREMENTS OF THE HALOS OF FOUR DARK MATTER-DOMINATED GALAXIES: DEVIATIONS FROM A UNIVERSAL DENSITY PROFILE1 Joshua D. Simon2, Alberto D. Bolatto2, Adam Leroy2, and Leo Blitz Department of Astronomy, 601 Campbell Hall, University of California at Berkeley, CA 94720 and Elinor L. Gates Lick Observatory, P.O. Box 85, Mount Hamilton, CA 95140 Accepted for publication in The Astrophysical Journal ABSTRACT We derive rotation curves for four nearby, low-mass spiral galaxies and use them to constrain the shapes of their dark matter density profiles. This analysis is based on high-resolution two-dimensional Hα velocity fields of NGC 4605, NGC 5949, NGC 5963, and NGC 6689 and CO velocity fields of NGC 4605 and NGC 5963. In combination with our previous study of NGC 2976, the full sample of five galaxies contains density profiles that span the range from αDM =0 to αDM =1.20, where αDM is the power law index describing the central density profile. The scatter in αDM from galaxy to galaxy is 0.44, three times as large as in Cold Dark Matter (CDM) simulations, and the mean density profile slope is αDM =0.73, shallower than that predicted by the simulations. These results call into question the hypothesis that all galaxies share a universal dark matter density profile. We show that one of the galaxies in our sample, NGC 5963, has a cuspy density profile that closely resembles those seen in CDM simulations, demonstrating that while galaxies with the steep central density cusps predicted by CDM do exist, they are in the minority. -
Vol. 73, No. 1 December 2020
Published by the Astronomical League Vol. 73, No. 1 December 2020 PUBLIC OUTREACH DURING A PANDEMIC THE ULTIMATE OBSERVING CHALLENGE th 75 GEAR UP FOR SOLAR CYCLE 25 THE ASTRONOMICAL LEAGUE’S 75TH ANNIVERSARY Contents AN EMPLOYEE-OWNED COMPANY NEW FREE SHIPPING on order of $75 or more INSTALLMENT BILLING on orders over $350 PRODUCTS & PAGE 16 Standard Shipping. Some exclusions apply. Exclusions apply. 4 . To the Editor 4 . Star Beams (from the President) 5 . International Dark-Sky Association 5 . Night Sky Network Orion® StarShoot™ Compact Astro 6 . Full STEAM Ahead Orion® StarShoot™ Mini 6.3mp Tracker Imaging Cameras (sold separately) Orion® StarShoot™ G26 APS-C Orion® GiantView™ BT-100 ED #21192 $280 7 . Wanderers in the Neighborhood Color #51883 $400 Color Imaging Camera 90-degree Binocular Telescope (Mount not Mono #51884 $430 #51458 $1,800 #51878 $2,600 included) PAGE 12 9 . Deep-Sky Objects computer not 10 . From Around the League Trust 2019 included 12 . Public Outreach During a Pandemic Proven reputation for Orion® U-Mount innovation, dependability and and Paragon Plus . service… for over 45 years! XHD Package 14 My Herschel Objects Project #22115 $600 Is Complete Superior Value Orion® StarShoot™ Deep Space High quality products at Orion® StarShoot™ G21 Deep Space Imaging Cameras (sold separately) Orion® HDX 12" Truss RC Ultimate 16 . First Light: Astronomical League affordable prices Color Imaging Camera G10 Color #51452 $1,200 Astro- Imaging Package PAGE 23 Origins and History #54290 $950 G16 Mono #51457 $1,300 #21101 $9,500 Wide Selection 18 . Everest of the Sky Extensive assortment of award winning Orion brand 2019 20 . -
Rotation and Mass in the Milky Way and Spiral Galaxies
Publ. Astron. Soc. Japan (2014) 00(0), 1–34 1 doi: 10.1093/pasj/xxx000 Rotation and Mass in the Milky Way and Spiral Galaxies Yoshiaki SOFUE1 1Institute of Astronomy, The University of Tokyo, Mitaka, 181-0015 Tokyo ∗E-mail: [email protected] Received ; Accepted Abstract Rotation curves are the basic tool for deriving the distribution of mass in spiral galaxies. In this review, we describe various methods to measure rotation curves in the Milky Way and spiral galaxies. We then describe two major methods to calculate the mass distribution using the rotation curve. By the direct method, the mass is calculated from rotation velocities without employing mass models. By the decomposition method, the rotation curve is deconvolved into multiple mass components by model fitting assuming a black hole, bulge, exponential disk and dark halo. The decomposition is useful for statistical correlation analyses among the dynamical parameters of the mass components. We also review recent observations and derived results. Full resolution copy is available at URL: http://www.ioa.s.u-tokyo.ac.jp/∼sofue/htdocs/PASJreview2016/ Key words: Galaxy: fundamental parameters – Galaxy: kinematics and dynamics – Galaxy: structure – galaxies: fundamental parameters – galaxies: kinematics and dynamics – galaxies: structure – dark matter 1 INTRODUCTION rotation curves of the Milky Way and spiral galaxies, respec- tively, and describe the general characteristics of observed rota- tion curves. The progress in the rotation curve studies will be Rotation of spiral galaxies is measured by spectroscopic ob- also reviewed briefly. In section 4 we review the methods to de- arXiv:1608.08350v1 [astro-ph.GA] 30 Aug 2016 servations of emission lines such as Hα, HI and CO lines from termine the mass distributions in disk galaxies using the rotation disk objects, namely population I objects and interstellar gases. -
Was 49B: an Overmassive AGN in a Merging Dwarf Galaxy?
A Preprint typeset using LTEX style emulateapj v. 5/2/11 WAS 49B: AN OVERMASSIVE AGN IN A MERGING DWARF GALAXY? Nathan J. Secrest1,5, Henrique R. Schmitt2, Laura Blecha3, Barry Rothberg4,5, and Jacqueline Fischer2 1National Academy of Sciences NRC Research Associate, resident at Naval Research Laboratory; [email protected] 2Naval Research Laboratory, Remote Sensing Division, 4555 Overlook Ave. SW, Washington, DC 20375, USA 3University of Maryland Dept. of Astronomy, 1113 PSC, Bldg. 415, College Park, MD 20742, USA 4LBT Observatory, University of Arizona, 933 N. Cherry Ave., Tuscan, AZ 85721, USA and 5Department of Physics & Astronomy, George Mason University, MS 3F3, 4400 University Drive, Fairfax, VA 22030, USA ABSTRACT We present a combined morphological and X-ray analysis of Was 49, an isolated, dual AGN system notable for the presence of a dominant AGN Was 49b in the disk of the primary galaxy Was 49a, at a projected radial distance of 8 kpc from the nucleus. Using X-ray data from Chandra, NuSTAR, and 45 −1 Swift, we find that this AGN has a bolometric luminosity of Lbol ∼ 2 × 10 erg s , with a black +2.9 8 hole mass of MBH =1.3−0.9 × 10 M⊙. Despite its large mass, our analysis of optical data from the Discovery Channel Telescope shows that the supermassive black hole is hosted by a stellar counterpart +4.9 9 with a mass of only 5.6−2.6 ×10 M⊙, making the SMBH potentially larger than expected from SMBH- galaxy scaling relations, and the stellar counterpart exhibits a morphology that is consistent with dwarf elliptical galaxies. -
Hands-On Radio Astronomy Mapping the Milky Way
Hands-On Radio Astronomy Mapping the Milky Way Cathy Horellou & Daniel Johansson Onsala Space Observatory Chalmers University of Technology Date of last revision: 2010 October 4, CH SE-439 92 Onsala Sweden Contents Abstract 3 1 Welcome to the Galaxy 4 1.1 WhereareweintheMilkyWay? . 5 1.1.1 Galactic longitude and latitude . ..... 5 1.1.2 Notations ................................... 5 1.2 Lookingforhydrogen.............................. ... 6 1.3 TheDopplereffect ................................. 7 2 The theory behind the Milky Way 9 2.1 Preliminarycalculations . ...... 9 2.2 Howdoesthegasrotate?............................ 10 2.3 Whereisthegas?................................... 11 2.4 EstimatingthemassofourGalaxy . ..... 13 3 Observing with Such A Lovely Small Antenna (SALSA) 14 3.1 SALSA-Onsala .................................... 14 3.2 Beforetheobservations. ..... 14 3.3 HowtoobservewithSALSA-Onsala. ..... 14 3.3.1 NX....................................... 15 3.3.2 qradio ..................................... 15 3.3.3 kstars: A planetarium program to control the radio telescope . 17 4 After the observations – my first maps of the Milky Way 19 4.1 Software........................................ 19 4.2 Dataprocessing.................................. 19 4.3 Dataanalysis .................................... 20 4.3.1 Rotationcurve ................................ 20 4.3.2 MapoftheMilkyWay ............................ 22 Appendices 24 A Rotation curves 25 A.1 Solid-bodyrotation .............................. 25 A.2 Keplerianrotation: theSolarsystem -
Dark Matter Halos of Spiral Galaxies
Dark Matter Halos of Spiral Galaxies Arunima Banerjee National Centre for Radio Astrophysics Tata Institute of Fundamental Research Pune, India email: [email protected] Web: http://www.ncra.tifr.res.in/~arunima PLAN OF THE TALK • Spiral Galaxies: An Overview • Dark Matter: A Brief History • LCDM model: Success & Failure • Tracking DM halos using HI Rotation Curve & Scale height data • Application & Results • Summary Spiral Galaxies: An Overview OUR MILKY WAY OTHER SPIRAL GALAXIES NGC 891 NGC 628 THE GALAXY CLASSIFICATION SCHEME NGC 628 FACE-ON SPIRAL GALAXY NGC 891 M87 EDGE-ON SPIRAL GALAXY ELLIPTICAL GALAXY BASIC BUILDING BLOCKS OF A SPIRAL GALAXY σ MASS ∆R ∆Z (km/s) (Msun ) (KPC) (KPC) Differential Rotation DM 10 12 200 200 STARS 10 11 10 0.350 18 Caveat: Not to Scale! GAS(HI) 10 10 30 0.15 - 1 7-9 R A MULTI-WAVELENGTH VIEW OF THE MILKY WAY GALAXY ENVIRONMENT: CLUSTER, GROUP, FIELD Cluster Group Abell 1689 Field Robert’s Quartet NGC 891 Dark Matter: A Brief History DARK MATTER: CLUSTER KINEMATICS (1933) Fritz Zwicky From Virial Theorem, Coma Cluster (Abell 1669) T + V = 0 Estimable from the Doppler Shifts of the i.e. V = -T galaxy spectra Hints at the existence of Dark Matter! But Estimable from the lumininosities of the V >> Vobs !! galaxies DARK MATTER: GALAXY ROTATION CURVE (1980) Vera Rubin Observed M(R) ~ R !! VROT =(GM/R)½ R Vrot (km/s) R(kpc) DARK MATTER: LARGE SCALE STRUCTURE AND COSMOLOGY Observed Large Scale Structure (SDSS) Ansotropies in the Cosmic Microwave Background (WMAP) Abundance of H, He, Li ΛCDM: STANDARD MODEL OF COSMOLOGY ORDINARY MATTER! Matter-energy budget in the LCDM universe which consists of dark energy and cold, dissipationless and collisionless dark matter LCDM Model: Success & Failure DARK MATTER DISTRIBUTION IN THE UNIVERSE AT PRESENT TIME Millenium Simulation LCDM HALOS: A ONE-SLIDE PRIMER Bett et al.