DOCSLIB.ORG

The Evolution of Cluster E and S0 Galaxies Measured from The

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Evolution of Cluster E and S0 Galaxies Measured from The A Mon. Not. R. Astron. So c. 000, 000{000 (0000) Printed 12 May1999 (MN L T Xstyle le v1.4) E The evolution of cluster E and S0 galaxies measured from ? the Fundamental Plane 1;2 yzx 3;4;5 zx 6;7;8 x 3;5 x Inger Jrgensen Marijn Franx , Jens Hjorth , Pieter G. van Dokkum 1 McDonald Observatory, The University of Texas at Austin, RLM 15.308, Austin, TX 78712, USA 2 Gemini Observatory, 670 N. A`ohoku Pl., Hilo, HI 96720, USA (Postal address for IJ) 3 Kapteyn Institute, P.O.Box 800, 9700 AVGroningen, The Netherlands 4 Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 5 Leiden Observatory, P.O.Box 9513, 2300 RA Leiden, The Netherlands (Postal address for MF and PvD) 6 Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK 7 NORDITA, Blegdamsvej 17, DK-2100 Copenhagen , Denmark 8 Astronomical Observatory, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen , Denmark (Postal address for JH) May 5, 1999, accepted for publication in Mon. Not. Royal Astron. Sco., Gemini Preprint #43 ABSTRACT Photometry has b een obtained for magnitude limited samples of galaxies in the two rich clusters Ab ell 665 (37 galaxies) and Ab ell 2218 (61 galaxies). Both clusters have m a redshift of 0.18. The limiting magnitude of the samples is 19 in the I-band. Sp ec- troscopy has b een obtained for seven galaxies in A665 and nine galaxies in A2218, all of whichalsohaveavailable photometry. Sp ectroscopy has b een obtained for two additional galaxies in A2218, one of whichisabackground galaxy. E ectiveradiir and mean surface brightnesses <I> were derived from the pho- e e tometry. The typical uncertainties are 0:078 in log r and 0:12 in log <I> . The e e combination log r +0:82 log <I> that enters the Fundamental Plane (FP) has an un- e e certainty of only 0:018. The sp ectroscopywas used for measurements of the velo city disp ersions, . The typical uncertaintyis 0:023 on log . The data are used to establish the FP,logr = log + log <I> + , for the e e clusters. The FP for these two clusters adds imp ortantknowledge ab out the prop erties of E and S0 galaxies in the relatively unexplored redshift interval 0.05 to 0.3. Wehave compared the FP for A665 and A2218 with the FP for the three clusters CL0024+16, CL1358+62 and MS2053-04 with redshifts between 0.33 and 0.58, and with the FP for the Coma cluster. The scatter around the FP is similar for all six clusters. We nd that the FP for the intermediate redshift clusters has a smaller co ecient than found for the Coma cluster and other nearby clusters. This mayeitherbecausedby selection e ects for the intermediate redshift clusters or by di erences in the evolution of low luminosity galaxies and high luminosity galaxies. The mass-to-light (M/L) ratios, as measured from the FP,change with redshift. At z =0.18 the M/L ratio for photometry in Gunn r in the rest frame of the clusters is (11 7)% smaller than for the Coma cluster. Using the data for A665 and A2218 together with the previously published data for CL0024+16, CL1358+62 and MS2053- 04, we nd that the M/L ratios for photometry calibrated to Gunn r change with redshift as log M=L =(0:26 0:06)z for q =0:5. This change in the M/L ratio r o is equivalent to the absolute magnitudes changing as M =(0:65 0:15)z .These r T new results are consistent with the previously published analysis for CL0024+16, CL1358+62 and MS2053-04. For q =0:5 the results are consistent with passiveevolution of a stellar p opulation o which formed at a redshift larger than ve. For q =0:15 the formation redshift must o b e larger than 1.7. Our new data for A665 and A2218 con rm the gradual and slow evolution of the bright E and S0 galaxies. However, p ossible star formation in E and S0 galaxies during the last 3-4 Gyr of the history of the Universe, as well as the selection e ects complicate the interpretation of the data. Key words: galaxies: clusters: individual: Ab ell 665, Ab ell 2218 { galaxies: elliptical and lenticular, cD { galaxies: evolution { galaxies: stellar content. c 0000 RAS 2 I. Jrgensen, M. Franx, J. Hjorth, P. G. van Dokkum plies a relation b etween the M/L ratios and the masses of 1 INTRODUCTION the galaxies. Observational studies show that the formation and evolu- The scatter of the FP is very low, equivalent to a scatter tion of galaxies is a complex pro cess, whichmayinvolve in- of 23% in the M/L ratio (e.g., JFK96). Thus, the FP o ers teractions, star bursts and infall (e.g., Dressler et al. 1994ab; the p ossibility of detecting even small di erences in the M/L Lilly et al. 1996; Mo ore et al. 1996). It has also b een found ratios by observing a handful of galaxies in a distant cluster. that some nearby E and S0 galaxies mayhave exp erienced The FP has been used to study the evolution of the star formation in the last 3-4 Gyr. Caldwell et al. (1993) M/L ratios of cluster galaxies as a function of redshift up found some E and S0 galaxies in the Coma cluster to have to a redshift of 0.83 (van Dokkum & Franx 1996; Kelson p ost-starburst sp ectra, and Fab er et al. (1995) suggest that et al. 1997; Bender et al. 1998; van Dokkum et al. 1998; nearby eld E galaxies havea substantial variation in the Pahre, Djorgovski & de Carvalho 1999). All of these studies mean age of their stellar p opulations. nd the M/L ratios of the galaxies to increase slowly with In order to study the evolution of galaxies we need to decreasing redshift. Only the study byPahre et al. contains study b oth the morphological evolution as well as the evolu- clusters with redshifts b etween 0.05 and 0.3. In this pap er tion of the luminosities and the mass-to-light (M/L) ratios of we establish the FP for the tworich clusters Ab ell 665 and the galaxies. High-resolution imaging with the Hubble Space Ab ell 2218. Both clusters have a redshift of 0.18, adding Telescop e (HST) and from the ground, combined with sp ec- data to a redshift interval not well-covered by the previous troscopy from the ground make it p ossible to carry out this studies. kind of studies. Studies of the morphological evolution show We use the data for A665 and A2218, data for the three that the fraction of spiral galaxies and irregular galaxies in clusters studied byvan Dokkum & Franx (1996) and Kelson clusters was higher at larger redshifts (e.g., Dressler et al. et al. (1997), and data for the Coma and the HydraI clusters 1994ab; Oemler et al. 1997; Dressler et al. 1997; Couchet to study how the FP and the M/L ratios of the E and S0 al. 1998). A detailed investigation of how the luminosities galaxies change with redshift. The full sample covers ab out of disk galaxies change with redshift is p ossible using the half the age of the Universe. Tully-Fisher (1977) relation. Vogt et al. (1996) established The available photometry and sp ectroscopy,aswell as the Tully-Fisher relation for a sample of eld galaxies with the derivation of the photometric and sp ectroscopic parame- redshifts b etween 0.1 and 1 and found a luminosityevolution ters is describ ed in Sections 2 and 3, resp ectively. The details m in the B-band of 0: 6between z = 1 and the present. of the data reduction are provided in App endix A and B. The Fundamental Plane (FP) (Dressler et al. 1987; App endix A also contains photometric parameters (e ective Djorgovski & Davis 1987) for elliptical galaxies makes it radii, mean surface brightnesses and colors) of magnitude p ossible to study how the luminosities and the M/L ra- limited samples of galaxies in A665 and A2218. Section 4 tios of these galaxies change with redshift. Also, S0 galaxies brie y describ es the data for the other clusters. The FP is in nearby clusters follow the FP (e.g., Jrgensen, Franx & analyzed in Section 5. In this section we also discuss the Kjrgaard 1996, hereafter JFK96). The FP relates the ef- evolution of the M/L ratios of the galaxies. The conclusions fective radius, r , the mean surface brightness within this e are summarized in Section 6. radius, <I> , and the (central) velo city disp ersion, , in e a tight relation, which is linear in log-space. For 226 E and S0 galaxies in nearby clusters JFK96 found log r = e 2 THE PHOTOMETRY 1:24 log 0:82 log <I> + cst, for photometry in Gunn r . e 0:24 0:02 This relation may be interpreted as M=L / M r e The central parts of the two rich clusters Ab ell 665 and (cf., Fab er et al. 1987). The change of the M/L ratio with Ab ell 2218 were observed with the Nordic Optical Telescop e the mass is partly caused bychanges in the stellar p opula- (NOT), La Palma, in March 1994. Observations were done in tions. Some of the apparentchange may also b e explained the I-band and the V-band.
Load more

Recommended publications
  • Experiencing Hubble
    PRESCOTT ASTRONOMY CLUB PRESENTS EXPERIENCING HUBBLE John Carter August 7, 2019 GET OUT LOOK UP • When Galaxies Collide https://www.youtube.com/watch?v=HP3x7TgvgR8 • How Hubble Images Get Color https://www.youtube.com/watch? time_continue=3&v=WSG0MnmUsEY Experiencing Hubble Sagittarius Star Cloud 1. 12,000 stars 2. ½ percent of full Moon area. 3. Not one star in the image can be seen by the naked eye. 4. Color of star reflects its surface temperature. Eagle Nebula. M 16 1. Messier 16 is a conspicuous region of active star formation, appearing in the constellation Serpens Cauda. This giant cloud of interstellar gas and dust is commonly known as the Eagle Nebula, and has already created a cluster of young stars. The nebula is also referred to the Star Queen Nebula and as IC 4703; the cluster is NGC 6611. With an overall visual magnitude of 6.4, and an apparent diameter of 7', the Eagle Nebula's star cluster is best seen with low power telescopes. The brightest star in the cluster has an apparent magnitude of +8.24, easily visible with good binoculars. A 4" scope reveals about 20 stars in an uneven background of fainter stars and nebulosity; three nebulous concentrations can be glimpsed under good conditions. Under very good conditions, suggestions of dark obscuring matter can be seen to the north of the cluster. In an 8" telescope at low power, M 16 is an impressive object. The nebula extends much farther out, to a diameter of over 30'. It is filled with dark regions and globules, including a peculiar dark column and a luminous rim around the cluster.
    [Show full text]
  • Star Formation Relations and CO Sleds Across the J-Ladder and Redshift 3 on the ESA Herschel Space Observatory20 (Pilbratt Et Al
    Draft version July 17, 2014 Preprint typeset using LATEX style emulateapj v. 5/2/11 STAR FORMATION RELATIONS AND CO SPECTRAL LINE ENERGY DISTRIBUTIONS ACROSS THE J-LADDER AND REDSHIFT T. R. Greve1, I. Leonidaki2, E. M. Xilouris2, A. Weiß3, Z.-Y. Zhang4,5, P. van der Werf6, S. Aalto7, L. Armus8, T. D´ıaz-Santos8, A.S. Evans9,10, J. Fischer11, Y. Gao12, E. Gonzalez-Alfonso´ 13, A. Harris14, C. Henkel3, R. Meijerink6,15, D. A. Naylor16 H. A. Smith17 M. Spaans15 G. J. Stacey18 S. Veilleux14 F. Walter19 Draft version July 17, 2014 ABSTRACT 0 We present FIR[50 − 300 µm]−CO luminosity relations (i.e., log LFIR = α log LCO + β) for the full CO rotational ladder from J = 1 − 0 up to J = 13 − 12 for a sample of 62 local (z ≤ 0:1) (Ultra) 11 Luminous Infrared Galaxies (LIRGs; LIR[8−1000 µm] > 10 L ) using data from Herschel SPIRE-FTS and ground-based telescopes. We extend our sample to high redshifts (z > 1) by including 35 (sub)- millimeter selected dusty star forming galaxies from the literature with robust CO observations, and sufficiently well-sampled FIR/sub-millimeter spectral energy distributions (SEDs) so that accurate FIR luminosities can be deduced. The addition of luminous starbursts at high redshifts enlarge the range of the FIR−CO luminosity relations towards the high-IR-luminosity end while also significantly increasing the small amount of mid-J/high-J CO line data (J = 5 − 4 and higher) that was available prior to Herschel. This new data-set (both in terms of IR luminosity and J-ladder) reveals linear FIR−CO luminosity relations (i.e., α ' 1) for J = 1 − 0 up to J = 5 − 4, with a nearly constant normalization (β ∼ 2).
    [Show full text]
  • Meeting Program
    A A S MEETING PROGRAM 211TH MEETING OF THE AMERICAN ASTRONOMICAL SOCIETY WITH THE HIGH ENERGY ASTROPHYSICS DIVISION (HEAD) AND THE HISTORICAL ASTRONOMY DIVISION (HAD) 7-11 JANUARY 2008 AUSTIN, TX All scientific session will be held at the: Austin Convention Center COUNCIL .......................... 2 500 East Cesar Chavez St. Austin, TX 78701 EXHIBITS ........................... 4 FURTHER IN GRATITUDE INFORMATION ............... 6 AAS Paper Sorters SCHEDULE ....................... 7 Rachel Akeson, David Bartlett, Elizabeth Barton, SUNDAY ........................17 Joan Centrella, Jun Cui, Susana Deustua, Tapasi Ghosh, Jennifer Grier, Joe Hahn, Hugh Harris, MONDAY .......................21 Chryssa Kouveliotou, John Martin, Kevin Marvel, Kristen Menou, Brian Patten, Robert Quimby, Chris Springob, Joe Tenn, Dirk Terrell, Dave TUESDAY .......................25 Thompson, Liese van Zee, and Amy Winebarger WEDNESDAY ................77 We would like to thank the THURSDAY ................. 143 following sponsors: FRIDAY ......................... 203 Elsevier Northrop Grumman SATURDAY .................. 241 Lockheed Martin The TABASGO Foundation AUTHOR INDEX ........ 242 AAS COUNCIL J. Craig Wheeler Univ. of Texas President (6/2006-6/2008) John P. Huchra Harvard-Smithsonian, President-Elect CfA (6/2007-6/2008) Paul Vanden Bout NRAO Vice-President (6/2005-6/2008) Robert W. O’Connell Univ. of Virginia Vice-President (6/2006-6/2009) Lee W. Hartman Univ. of Michigan Vice-President (6/2007-6/2010) John Graham CIW Secretary (6/2004-6/2010) OFFICERS Hervey (Peter) STScI Treasurer Stockman (6/2005-6/2008) Timothy F. Slater Univ. of Arizona Education Officer (6/2006-6/2009) Mike A’Hearn Univ. of Maryland Pub. Board Chair (6/2005-6/2008) Kevin Marvel AAS Executive Officer (6/2006-Present) Gary J. Ferland Univ. of Kentucky (6/2007-6/2008) Suzanne Hawley Univ.
    [Show full text]
  • The History of Enrichment of the Intergalactic Medium Using Cosmological Simulations
    The History of Enrichment of the Intergalactic Medium Using Cosmological Simulations Item Type text; Electronic Dissertation Authors Oppenheimer, Benjamin Darwin Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 03/10/2021 02:22:25 Link to Item http://hdl.handle.net/10150/194237 THE HISTORY OF ENRICHMENT OF THE INTERGALACTIC MEDIUM USING COSMOLOGICAL SIMULATIONS by Benjamin Darwin Oppenheimer A Dissertation Submitted to the Faculty of the DEPARTMENT OF ASTRONOMY In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College THE UNIVERSITY OF ARIZONA 2 0 0 8 2 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Dissertation Committee, we certify that we have read the dissertation prepared by Benjamin Darwin Oppenheimer entitled “The History of Enrichment of the Intergalactic Medium Using Cosmological Simulations” and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of Doctor of Philosophy. Date: August 6, 2008 Romeel Dave´ Date: August 6, 2008 Chris Impey Date: August 6, 2008 Jill Bechtold Date: August 6, 2008 Buell Jannuzi Date: August 6, 2008 John Bieging Final approval and acceptance of this dissertation is contingent upon the candi- date's submission of the final copies of the dissertation to the Graduate College. I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requirement.
    [Show full text]
  • Astronomy Magazine 2011 Index Subject Index
    Astronomy Magazine 2011 Index Subject Index A AAVSO (American Association of Variable Star Observers), 6:18, 44–47, 7:58, 10:11 Abell 35 (Sharpless 2-313) (planetary nebula), 10:70 Abell 85 (supernova remnant), 8:70 Abell 1656 (Coma galaxy cluster), 11:56 Abell 1689 (galaxy cluster), 3:23 Abell 2218 (galaxy cluster), 11:68 Abell 2744 (Pandora's Cluster) (galaxy cluster), 10:20 Abell catalog planetary nebulae, 6:50–53 Acheron Fossae (feature on Mars), 11:36 Adirondack Astronomy Retreat, 5:16 Adobe Photoshop software, 6:64 AKATSUKI orbiter, 4:19 AL (Astronomical League), 7:17, 8:50–51 albedo, 8:12 Alexhelios (moon of 216 Kleopatra), 6:18 Altair (star), 9:15 amateur astronomy change in construction of portable telescopes, 1:70–73 discovery of asteroids, 12:56–60 ten tips for, 1:68–69 American Association of Variable Star Observers (AAVSO), 6:18, 44–47, 7:58, 10:11 American Astronomical Society decadal survey recommendations, 7:16 Lancelot M. Berkeley-New York Community Trust Prize for Meritorious Work in Astronomy, 3:19 Andromeda Galaxy (M31) image of, 11:26 stellar disks, 6:19 Antarctica, astronomical research in, 10:44–48 Antennae galaxies (NGC 4038 and NGC 4039), 11:32, 56 antimatter, 8:24–29 Antu Telescope, 11:37 APM 08279+5255 (quasar), 11:18 arcminutes, 10:51 arcseconds, 10:51 Arp 147 (galaxy pair), 6:19 Arp 188 (Tadpole Galaxy), 11:30 Arp 273 (galaxy pair), 11:65 Arp 299 (NGC 3690) (galaxy pair), 10:55–57 ARTEMIS spacecraft, 11:17 asteroid belt, origin of, 8:55 asteroids See also names of specific asteroids amateur discovery of, 12:62–63
    [Show full text]
  • September 2017 BRAS Newsletter
    September 2017 Issue September 2017 Next Meeting: Monday, September 11th at 7PM at HRPO nd (2 Mondays, Highland Road Park Observatory) September Program: GAE (Great American. Eclipse) Membership Reports. Club members are invited to “approach the mike. ” and share their experiences travelling hither and thither to observe the August total eclipse. What's In This Issue? HRPO’s Great American Eclipse Event Summary (Page 2) President’s Message Secretary's Summary Outreach Report - FAE Light Pollution Committee Report Recent Forum Entries 20/20 Vision Campaign Messages from the HRPO Spooky Spectrum Observe The Moon Night Observing Notes – Draco The Dragon, & Mythology Like this newsletter? See past issues back to 2009 at http://brastro.org/newsletters.html Newsletter of the Baton Rouge Astronomical Society September 2017 The Great American Eclipse is now a fond memory for our Baton Rouge community. No ornery clouds or“washout”; virtually the entire three-hour duration had an unobstructed view of the Sun. Over an hour before the start of the event, we sold 196 solar viewers in thirty-five minutes. Several families and children used cereal box viewers; many, many people were here for the first time. We utilized the Coronado Solar Max II solar telescope and several nighttime telescopes, each outfitted with either a standard eyepiece or a “sun funnel”—a modified oil funnel that projects light sent through the scope tube to fabric stretched across the front of the funnel. We provided live feeds on the main floor from NASA and then, ABC News. The official count at 1089 patrons makes this the best- attended event in HRPO’s twenty years save for the historic Mars Opposition of 2003.
    [Show full text]
  • Arxiv:1701.08720V1 [Astro-Ph.CO]
    Foundations of Physics manuscript No. (will be inserted by the editor) Tests and problems of the standard model in Cosmology Mart´ın L´opez-Corredoira Received: xxxx / Accepted: xxxx Abstract The main foundations of the standard ΛCDM model of cosmology are that: 1) The redshifts of the galaxies are due to the expansion of the Uni- verse plus peculiar motions; 2) The cosmic microwave background radiation and its anisotropies derive from the high energy primordial Universe when matter and radiation became decoupled; 3) The abundance pattern of the light elements is explained in terms of primordial nucleosynthesis; and 4) The formation and evolution of galaxies can be explained only in terms of gravi- tation within a inflation+dark matter+dark energy scenario. Numerous tests have been carried out on these ideas and, although the standard model works pretty well in fitting many observations, there are also many data that present apparent caveats to be understood with it. In this paper, I offer a review of these tests and problems, as well as some examples of alternative models. Keywords Cosmology · Observational cosmology · Origin, formation, and abundances of the elements · dark matter · dark energy · superclusters and large-scale structure of the Universe PACS 98.80.-k · 98.80.E · 98.80.Ft · 95.35.+d · 95.36.+x · 98.65.Dx Mathematics Subject Classification (2010) 85A40 · 85-03 1 Introduction There is a dearth of discussion about possible wrong statements in the foun- dations of standard cosmology (the “Big Bang” hypothesis in the present-day Instituto de Astrof´ısica de Canarias, E-38205 La Laguna, Tenerife, Spain Departamento de Astrof´ısica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain arXiv:1701.08720v1 [astro-ph.CO] 30 Jan 2017 Tel.: +34-922-605264 Fax: +34-922-605210 E-mail: [email protected] 2 Mart´ın L´opez-Corredoira version of ΛCDM, i.e.
    [Show full text]
  • The Search for the Missing Baryons at Low Redshift
    Bregman 1 The Search for the Missing Baryons at Low Redshift Joel N. Bregman Department of Astronomy, University of Michigan Key Words astrophysics, cosmology, intergalactic medium Abstract The baryon content of the universe is known from Big Bang nucleosynthesis and cosmic microwave background considerations, yet at low redshift, only about one-tenth of these baryons lie in galaxies or the hot gas seen in galaxy clusters and groups. Models posit that these “missing baryons” are in gaseous form in overdense filaments that connect the much denser virialized groups and clusters. About 30% of the baryons are cool (<105 K) and are detected in Lyα absorption studies, but about half the mass is predicted to lie in the 105-107 K regime, where detection is very challenging. Material has been detected in the 2-5×105 K range through OVI absorption studies, indicating that this gas accounts for about 7% of the baryons. Hotter gas (0.5-2×106 K) has been detected at zero redshift by OVII and OVIII Kα absorption at X-ray energies. However, this appears to be correlated with the Galactic soft X-ray background, so it is probably Galactic Halo gas, rather than a cosmologically significant Local Group medium. There are no compelling detections of the intergalactic hot gas (0.5-10×106 K) either in absorption or in emission. Early claims of intergalactic X-ray absorption lines have not been confirmed, but this is consistent with theoretical models, which predited equivalent widths below current detection thresholds. There have been many investigations for emission from this gas, within and beyond the virial radius of clusters, but the positive signals for this soft emission are largely artifacts of background subtraction and field-flattening.
    [Show full text]
  • Dark Matter: Motivation, Candidates and Searches
    DARK MATTER: MOTIVATION, CANDIDATES AND SEARCHES G.G. RAFFELT Max-Planck-Institut fur Physik (Werner-Heisenberg-Institut) Fohringer Ring 6, 80805 Munchen, Germany Abstract The physical nature of most of the gravitating mass in the universe is com- pletely mysterious. The astrophysical evidence for the presence of this dark matter and astrophysical constraints on its properties will be reviewed. The most popular dark-matter candidates will be introduced, and current and fu- ture attempts to search for them directly and indirectly will be discussed. 1 INTRODUCTION The question of what makes up the mass density of the universe is practically as old as extragalactic as- tronomy which began with the recognition that nebulae such as M31 in Andromeda are actually galaxies like our own. Some of them appear in gravitationally bound clusters. From the Doppler shifts of the spectral lines of the galaxies in the Coma cluster, Zwicky derived in 1933 their velocity dispersion and could thus estimate the cluster mass with the help of the virial theorem [1]. He concluded that the Coma cluster contained far more dark than luminous matter when he translated the luminosity of the galaxies into a corresponding mass. Since then evidence has mounted that on galactic scales and above the mass density associated with luminous matter (stars, hydrogen clouds, x-ray gas in clusters, etc.) cannot ac- count for the observed dynamics on those scales [2, 3, 4, 5]. In the mid 1970s it had become clear that dark matter was an unavoidable reality [6] and by the mid 1980s the view had become canonical that the universe is dominated by an unknown form of matter or by an unfamiliar class of dark astrophysical Fig.
    [Show full text]
  • New Evidence for Dark Matter
    New evidence for dark matter A. Boyarsky1,2, O. Ruchayskiy1, D. Iakubovskyi2, A.V. Macci`o3, D. Malyshev4 1Ecole Polytechnique F´ed´erale de Lausanne, FSB/ITP/LPPC, BSP CH-1015, Lausanne, Switzerland 2Bogolyubov Institute for Theoretical Physics, Metrologichna str., 14-b, Kiev 03680, Ukraine 3Max-Planck-Institut f¨ur Astronomie, K¨onigstuhl 17, 69117 Heidelberg, Germany 4Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2, Ireland Observations of star motion, emissions from hot ionized gas, gravitational lensing and other tracers demonstrate that the dynamics of galaxies and galaxy clusters cannot be explained by the Newtonian potential produced by visible matter only [1–4]. The simplest resolution assumes that a significant fraction of matter in the Universe, dominating the dynamics of objects from dwarf galaxies to galaxy clusters, does not interact with electromagnetic radiation (hence the name dark matter). This elegant hypothesis poses, however, a major challenge to the highly successful Standard Model of particle physics, as it was realized that dark matter cannot be made of known elementary particles [4]. The quest for direct evidence of the presence of dark matter and for its properties thus becomes of crucial importance for building a fundamental theory of nature. Here we present a new universal relation, satisfied by matter distributions at all observed scales, and show its amaz- ingly good and detailed agreement with the predictions of the most up-to-date pure dark matter simulations of structure formation in the Universe [5–7]. This behaviour seems to be insensitive to the complicated feedback of ordinary matter on dark matter.
    [Show full text]
  • A Hubble & Spitzer Space Telescope Survey for Gravitationally-Lensed
    A Hubble & Spitzer Space Telescope Survey for Gravitationally-Lensed Galaxies: Further Evidence for a Significant Population of Low Luminosity Galaxies beyond Redshift Seven Johan Richard 1, Daniel P. Stark1, Richard S. Ellis1, Matthew R. George1,3, Eiichi Egami4, Jean-Paul Kneib 1,2, Graham P. Smith 1,5 ABSTRACT We present the results of a systematic search for gravitationally-lensed con- tinuum Lyman break ‘drop-outs’ beyond a redshift 7 conducted via very deep imaging through six foreground clusters undertaken with the Hubble and Spitzer Space Telescopes. The survey has yielded 10 z-band and 2 J-band drop-out can- didates to photometric limits of J 26.2 AB (5σ). Taking into account the 110 ≃ magnifications afforded by our clusters (1-4 magnitudes), we probe the presence of z >7 sources to unlensed limits of J 30 AB, fainter than those charted in 110 ≃ the Hubble Ultradeep Field. To verify the fidelity of our candidates we conduct a number of tests for instrumental effects which would lead to spurious detections, and carefully evaluate the likelihood of foreground contamination by consider- ing photometric uncertainties in the drop-out signature, the upper limits from stacked IRAC data and the statistics of multiply-imaged sources. Overall, we conclude that we can expect about half of our sample of z-band drop-outs to be at high redshift. An ambitious infrared spectroscopic campaign undertaken with the NIRSPEC spectrograph at the WM Keck Observatory for seven of the most promising candidates failed to detect any Lyman α emission highlighting the challenge of making further progress in this field.
    [Show full text]
  • Tesi Magistralee
    Investigating backgrounds to Dark Higgs searches at PADME Facoltà di Scienze Matematiche, Fisiche e Naturali Corso di Laurea Magistrale in Particle and Astroparticle Physics Candidate Gabriele Martelli ID number 1647148 Thesis Advisor Co-Advisor Prof. Mauro Raggi Dr. Gabriele Piperno Academic Year 2018/2019 Thesis defended on 24/01/2020 in front of a Board of Examiners composed by: Prof. Antonio Capone (chairman) Prof. Valerio Parisi Prof. Cesare Bini Prof. Paola Leaci Prof. Marco Nardecchia Prof. Roberto Maoli Prof. Fabio Anulli Investigating backgrounds to Dark Higgs searches at PADME Master thesis. Sapienza – University of Rome © 2019 Gabriele Martelli. All rights reserved This thesis has been typeset by LATEX and the Sapthesis class. Author’s email: [email protected] v Acknowledgments Firstly, I would like to express my sincere gratitude to my advisor Prof. Mauro Raggi for the continuous support of my thesis work, for his patience, and motivation. His guidance helped me in all the time of work and writing of this thesis. I could not have imagined having a better advisor and mentor for my university study. Besides my advisor, I would like to thank my co-advisor Dr. Gabriele Piperno and Dr. Emanuele Leonardi from the PADME collaboration for their insightful comments and encouragement, but also for the hard question which stimulated me to extend my work from various perspectives. Last but not the least, I would like to thank my family and my friends for supporting me spiritually throughout writing this thesis and my life in general. vii Contents Introduction ix 1 The Dark Matter problem 1 1.1 Standard Cosmological Model .
    [Show full text]