DOCSLIB.ORG

The Hidden Universe Revealed at Submm Wavelengths - IV

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Hidden Universe Revealed at Submm Wavelengths - IV The Hidden Universe revealed at submm wavelengths - IV David Hughes INAOE, Tonantzintla, Puebla, Mexico Evolution of morphology, number-density, physical scale & luminosity of structure distance, redshift (z) or scale-factor of universe optical HST observer GTM dΩ submm JCMT provide N(>flux, mass|distance)/unit area • surveying the universe (i.e. counting the number of galaxies as a function of distance and brightness, and spatial distribution) is the most fundamental observation to understand the evolution of galaxies and clusters •the observed (submillimetre-wavelength luminosity provides a measure of the star formation rate (since dust absorbs UV-optical radiation from young stars and themally re-radiates at longer FIR-mm wavelengths) Arp 220 (z=0.018) Detecting dust (& galaxy formation) L = 2x1012 L FIR ~ at high-redshift redshift 850µm . z=0.1 ... Flux density z=1 Current SCUBA detection limit . z=3 z=6 z=11 radio 850µm IR observed wavelength Difference between SCUBA & Bolocam surveys of Lockman Hole Bolocam 1.1mm CSO survey 17 sources in 324 sq. arcmin (Laurent etal 2005 astro-ph/0503249) only 8 overlap with SCUBA UK 8mJy SCUBA 850um survey Sub-mm & mm extragalactic survey source-counts (from Laurent et al. 2005) IRAS FIR (60um) luminosity function z=2 z=1 L(z)= L (1+z)3 at z=1, L(z) = 8 L at z=2, L(z) = 27 L L 10L 100L G R I Saunders etal. 1990 L H MNRAS, 242, 318 ULIRG Soifer etal. 1986, ApJ Lett. 303, L41 Summary of results from confusion-limited (sub)mm surveys Access to the highest-redshift Universe, potentially un-limited at mm-λ Basic catalogue: • Less than 200 (sub)mm sources detected (S/N > 3) • Positions with uncertainty ~ 2-3 arcsecs (given 11-15” FWHM) • Sub-mm (SCUBA) and mm (MAMBO) surveys are sensitive 12 to the detection of galaxies with FIR luminosities > 3. 10 L~ and star-formation rates SFRs > 300 M~ /yr (cf. ULIRGS) .... if galaxies lie at z>1 Need identifications, redshifts, SEDs, morphology of hosts, environment (galaxy interaction rate), fraction of (buried?) AGN, stellar masses, gas (HI, HII, H2) masses ……… Most questions on the nature of the (sub)mm galaxy population require additional X-ray to radio follow-up larger telescopes higher resolution lower confusion limit increased sensitivity 170µm SPITZER 850µm JCMT SPITZER 3mm LMT larger-format cameras increased field-of-view faster mapping speed improved source statistics Plan of lectures I. The Cold Universe. Basic observational properties of the ISM and galaxies at FIR-mm wavelengths. Overview of reasons why submm observations are a necessary contribution to the understanding of the evolutionary history of galaxies and clusters. The early history of FIR-mm astronomy. II. Dust grains and thermal radiation. IR-mm wavelength spectral energy distributions of starburst galaxies. Calculation of dust masses & SFRs. K-corrections. Arguments to support expectation for luminous submm galaxies in the high-redshift universe. III. Dust-production by supernovae at high-z? Submm telescopes & instruments. Confusion limits, biases & survey design. Submm galaxy surveys. Evolutionary history of submm population. IV. Multi-wavelength follow-up of high-redshift submm population. Breaking the redshift deadlock: spectroscopic vs. photometric redshift techniques. Physical nature of submm galaxies. Identifying clusters at submm wavelengths via the Sunyaev-Zeldovich effect. Prospects for the future (including the LMT). UK 8 mJy SCUBA survey of the Lockman Hole & ELAIS N2 fields (Scott et al. 2002, Fox etal. 2002) Lockman Hole Hubble Deep Field (850um SCUBA survey Hughes et al. 1998) UK 8mJy survey 260 sq. arcmin 850um survey 2.5mJy r.m.s. at 850um 19 sources (S/N > 4), 38 sources (S/N > 3.5) 10 arcsecs SCUBA survey of the Hubble Deep Field Hughes etal. 1998, Nature, 394, 241 160 arcsecs 15-m James Clerk Maxwell Telescope (JCMT) Mauna Kea, Hawaii ~ 4100 m 15 arcsecond beam-size at 850um σposition ≈Θbeam / (2 S/N) e.g. S/N ~ 4 ~2 “ Problems associated with identifying counterparts to FIR, sub-mm & mm sources with low-resolution experiments • Positional uncertainty of submm sources due to S/N of source-extraction σposition ≈Θbeam / (2 S/N), + random pointing uncertainty of telescope (~ 1 – 2”) • Invisible or extremely faint optical, IR or radio counterparts and hence ambiguity in identifying counterparts. causes difficulty in determining the nature and star formation history of the submm population z = 0.7 (opt) z =2.35 (IR) 30 arcsec 30 arcsec 10 arcsec z = 0.7 (opt) z > 2 (IR) 10 arcsec Before - which optical/IR counterpart ? Now (with HST) - which component of which counterpart? ~4 arcsec ~150 arcsec IRAM PdB 1.3mm (Downes et al. 1999) JCMT 850µm SCUBA MERLIN+VLA 1.4GHz (Dunlop et al. 2002) (Hughes et al. 1998) Follow up of HDF SCUBA survey: HDF850.1 K = 23.5±0.2 Subaru 9 hours VLA follow-up at 1.4GHz HST/NICMOS From our Monte-Carlo simulations, I > 28.7, I-K > 5.2 we determine that in order to detect 80% of the 8mJy sub-mm galaxies with a significance >3σ, the 1.4GHz follow-up observations have to be carried out to a 3σ depth of ~5µJy. Typical depths are a few × 10 µJy over limited-areas The optical data (with the 3σ error-bars) constrain 3.0 ≤ zphot ≤ 5.2 Dunlop et al. 2004 Hughes et al. 2002, MNRAS, 335, 871 Ambiguity in optical/IR identifications redshift? luminosity? SFR ? z = 0.7 (opt) z > 2 (IR) The Achilles heel of all photometric redshift techniques Only a few dozens of well measured SEDs known, including starbursts, ULIRGs and AGN. Are they representative enough of the high-z Universe? Is there any luminosity or redshift evolution of the SEDs? None is included in order to play conservatively Library of 20 SEDs of nearby starbursts galaxies, ULIRGs and AGN, normalized at 60µm. They cover the luminosity range 9 12 10 ≤ LFIR/L ≤ 3 × 10 and the temperature range 25 ≤ T/K ≤ 65 (model dependent!) which offers a wide range of shape dispersion Radio to sub-mm photometric-z estimation normalised at 60um L(1.4 GHz) L(FIR) SEDs of local 20 AGN and starburst galaxies normalised at 60um synchrotron/ rel. electrons SN OB stars dust thermal/dust SEDs of local 20 AGN and starburst galaxies Radio to sub-mm photometric-z estimation using 850µm & 1.4GHz - assumes FIR/radio correlation holds at high-z (Hughes et al. 1998, Carilli & Yun 1999, Yun & Carilli 2000, Dunne et al. 2000, Eales et al. 2000) (Carilli & Yun 2000) Lacking a rigorous analysis of photometric, calibration errors, and uncertainties in SED population Radio identifications of UK 8 mJy survey (Ivison et al. 2002) Optical K-band + submm radio Star formation history Ivison et al. 2002 based on radio-FIR photometric redshifts Spectroscopic observations of SCUBA galaxies targeted 34 radio-detected submm galaxies with ESI and LRIS on Keck ESI couterparts I=22.2 – 26.4, i.e. assumes all have radio IDs and optical counterparts yet, already seen evidence to the contrary quotes from Chapman et al. “taught ourselves to recognise the counterpart” “go for the most disturbed-looking object” “even if it’s the wrong object, it’s probably a galaxy associated with the correct ID” Chapman et al. 2003, Nature, 422, 695 Redshift distribution of blank-field sub-mm sources 14 “well-constrained” sources in the UK 8mJy survey (Scott et al. 2002) Keck z’s “missing” due to radio-selection bias 70-80% of submm galaxies at 2 < z < 4 50% of galaxies at 1.9 < z < 2.8 (Aretxaga et al. 2003) (Chapman et al. 2003) Chapman et al 2003 Chapman et al 2005 astroph/0412573 median z = 2.2, 1.7(25%) – 2.8 (75%) median L(FIR) ~ 9e12 Lsun sub-mm surveys undertaken have detected 200 sources, however, in general, their identifications and redshifts are uncertain, hence their evolutionary history is uncertain. radio-submm redshifts discriminate z<2 from z> 2,andIR seems the most successful method to identify counterparts, provided K=21-23. z = 0.7 (opt) z > 2 (IR) Is there a better way to estimate redshifts? Conclusions from exisiting sub-mm follow-up; • the consequence of the ambiguity and inherent biases in the identifications of the optical, IR and radio counterparts to blank-field submm sources is that the z-distribution for the whole population is still poorly constrained •the observing time required to provide ultra-deep radio/mm (e.g. VLA, IRAM PdB), optical and IR imaging, and then optical and/or IR spectroscopic follow-up for each sub-mm source is prohibitive (>> 20 hours/galaxy) • therefore, there is both an increasing need for larger samples from wider-area and deeper submm surveys to better constrain counts and clustering (i.e. to challenge formation models and history of evolution), and to provide robust and unambiguous means to derive the redshift distribution and to unambiguously identify counterparts P.I. Mark Devlin Constraining the star formation history of obscured galaxies • requires FIR luminosities (SFR) and redshifts Need photometric colours that bracket the rest-frame FIR peak in the SED at all redshifts – ideally data at 1000 – 50um. TFIR=70K z=1 Flux density TFIR=70K z=4 350 IR radio 500µm 250µm observed wavelength Long-duration balloon-flight mirror Test-flight mirror 2-m (by COI) 1.8 m (by Bosma) September 2003 http://chile1.physics.upenn.edu/blastpublic/ BLAST overview • 2-m primary aperture • Simultaneous imaging 250, 350 & 500 microns • Resolution 30, 45, 60 arcsecs •Arrays -FOV 85 sq. arcmins (cf. 3 sq. arcmin with SCUBA, MAMBO) • Conduct 10-15 day long duration balloon (LDB) flights • Example 50-hr survey – map 1 sq deg, 1 sigma = 5 mJy in all 3 bands and detect 800 galaxies • goal: to combine with existing & future ground-based (mm) and satellite (FIR) surveys provide additional colour information and constrain redshifts, and hence luminosities and SFRs • Kiruna (Sweden) April-May-June 2005 Long-Duration Balloon (LDB) flight • Antarctica December 2006 LDB 10-15 days 250 µm 350 µm BLAST observes simultaneously at 3 wavelengths each array has FOV ~ 85 sq.
Load more

Recommended publications
  • UNIVERSIT`A DEGLI STUDI DI TRIESTE Using Hydrodynamical
    UNIVERSITA` DEGLI STUDI DI TRIESTE Facolt`adi Scienze Matematiche, Fisiche e Naturali Dottorato di Ricerca in Fisica - XX Ciclo Using hydrodynamical simulations to combine Sunyaev–Zeldovich and X–ray studies of galaxy clusters DOTTORANDA COORDINATORE DEL COLLEGIO DEI DOCENTI Silvia Ameglio Chiar.mo Prof. Gaetano Senatore, Universit`adi Trieste TUTORE Chiar.mo Prof. Stefano Borgani, Universit`adi Trieste RELATORE Chiar.mo Prof. Stefano Borgani, Universit`adi Trieste a.a. 2006/2007 Contents 1 Introduction 1 2 Clusters of galaxies: an overview 5 2.1 X–rayemission ................................. 6 2.2 The Sunyaev–Zeldovich effect (SZ) . ... 8 2.2.1 The thermal Sunyaev–Zeldovich effect (tSZ) . .... 8 2.2.2 The kinetic Sunyaev–Zeldovich effect . 11 2.3 Statusofobservations . .. .. .. .. .. .. .. .. 11 2.3.1 X–rays.................................. 11 2.3.2 The Sunyaev–Zeldovich effect . 17 2.4 Cosmology with galaxy clusters . 23 2.5 Conclusions ................................... 29 3 Hydrodynamical simulations of galaxy clusters 31 3.1 The gravitational dynamics: the N–body TREE code . ...... 31 3.2 The gas physics: Smoothed Particle Hydrodynamics (SPH) ........ 33 3.3 Thesetofsimulatedclusters . 35 3.3.1 Thermal processes in the IntraCluster Medium (ICM) . ..... 38 3.3.2 The sample of simulated clusters . 40 3.3.3 Generation of tSZ, X–ray and temperature maps . 41 3.4 Definitionsoftemperature. 45 4 The angular diameter distance measurement 51 4.1 The polytropic β–model ............................ 53 4.2 DA from combined X-ray and tSZ observations . 53 4.3 Results...................................... 55 4.3.1 Resultsfromtheisothermalmodel . 55 4.3.2 Resultsfromthepolytropicfit . 57 4.3.3 Implications for cosmological parameters . ...... 60 4.4 Conclusions ..................................
    [Show full text]
  • 2006-2007 Science Planning Summaries
    Project Indexes Find information about projects approved for the 2006-2007 USAP field season using the available indexes. Project Web Sites Find more information about 2006-2007 USAP projects by viewing project web sites. More Information Additional information pertaining to the 2006-2007 Field Season. Home Page Station Schedules Air Operations Staffed Field Camps Event Numbering System 2006-2007 USAP Field Season Project Indexes Project Indexes Find information about projects approved for the 2006-2007 USAP field season using the USAP Program Indexes available indexes. Aeronomy and Astrophysics Dr. Bernard Lettau, Program Director (acting) Project Web Sites Biology and Medicine Dr. Roberta Marinelli, Program Director Find more information about 2006-2007 USAP projects by Geology and Geophysics viewing project web sites. Dr. Thomas Wagner, Program Director Glaciology Dr. Julie Palais, Program Director More Information Ocean and Climate Systems Additional information pertaining Dr. Bernhard Lettau, Program Director to the 2006-2007 Field Season. Artists and Writers Home Page Ms. Kim Silverman, Program Director Station Schedules USAP Station and Vessel Indexes Air Operations Staffed Field Camps Amundsen-Scott South Pole Station Event Numbering System McMurdo Station Palmer Station RVIB Nathaniel B. Palmer ARSV Laurence M. Gould Special Projects Principal Investigator Index Deploying Team Members Index Institution Index Event Number Index Technical Event Index Project Web Sites 2006-2007 USAP Field Season Project Indexes Project Indexes Find information about projects approved for the 2006-2007 USAP field season using the Project Web Sites available indexes. Principal Investigator/Link Event No. Project Title Aghion, Anne W-218-M Works and days: An antarctic Project Web Sites chronicle Find more information about 2006-2007 USAP projects by Ainley, David B-031-M Adélie penguin response to viewing project web sites.
    [Show full text]
  • Observational Cosmology - 30H Course 218.163.109.230 Et Al
    Observational cosmology - 30h course 218.163.109.230 et al. (2004–2014) PDF generated using the open source mwlib toolkit. See http://code.pediapress.com/ for more information. PDF generated at: Thu, 31 Oct 2013 03:42:03 UTC Contents Articles Observational cosmology 1 Observations: expansion, nucleosynthesis, CMB 5 Redshift 5 Hubble's law 19 Metric expansion of space 29 Big Bang nucleosynthesis 41 Cosmic microwave background 47 Hot big bang model 58 Friedmann equations 58 Friedmann–Lemaître–Robertson–Walker metric 62 Distance measures (cosmology) 68 Observations: up to 10 Gpc/h 71 Observable universe 71 Structure formation 82 Galaxy formation and evolution 88 Quasar 93 Active galactic nucleus 99 Galaxy filament 106 Phenomenological model: LambdaCDM + MOND 111 Lambda-CDM model 111 Inflation (cosmology) 116 Modified Newtonian dynamics 129 Towards a physical model 137 Shape of the universe 137 Inhomogeneous cosmology 143 Back-reaction 144 References Article Sources and Contributors 145 Image Sources, Licenses and Contributors 148 Article Licenses License 150 Observational cosmology 1 Observational cosmology Observational cosmology is the study of the structure, the evolution and the origin of the universe through observation, using instruments such as telescopes and cosmic ray detectors. Early observations The science of physical cosmology as it is practiced today had its subject material defined in the years following the Shapley-Curtis debate when it was determined that the universe had a larger scale than the Milky Way galaxy. This was precipitated by observations that established the size and the dynamics of the cosmos that could be explained by Einstein's General Theory of Relativity.
    [Show full text]
  • National Science Foundation
    This document has been archived. National Science Foundation U.S. Antarctic Program 1999-2000 National Science Foundation U.S. Antarctic Program 1999-2000 i CONTENTS U.S. Antarctic Program, 1999-2000 . .ii Aeronomy and Astrophysics . 1 Biology and Medicine . 12 Antarctic Pack Ice Seals . 25 Long-term ecological research . 28 Environmental Monitoring Program . 31 Geology and Geophysics . 32 Cape Roberts International Drilling Project . 47 Glaciology . 51 Siple Dome Ice Coring . 55 International Trans-Antarctic Scientific Expedition . 57 Ocean and Climate Systems . 60 ii During the 1999-2000 austral summer and the Station by a team of scientists from the PROGRAM,U.S. ANTARCTIC 1999-2000 2000 austral winter, the U.S. Antarctic Program United States, New Zealand, Italy, Australia, will support more than 800 researchers and the United Kingdom, and Germany other participants in the U.S. Antarctic Program • long-term ecological research in the at three year-round stations (McMurdo, McMurdo Dry Valleys and in the Palmer Amundsen-Scott South Pole, and Palmer), Station region of the Antarctic Peninsula aboard two research ships (Laurence M. Gould and Nathaniel B. Palmer) in the Ross Sea and in Science teams also will use networks of the Antarctic Peninsula region, at remote field automatic weather stations, automated geo- camps, and in cooperation with the national physical observatories, ultraviolet-radiation antarctic programs of the other Antarctic Treaty monitors, and a high-altitude, long-duration nations. These projects, funded and managed balloon that will circumnavigate the continent by the National Science Foundation (NSF), are and carry instruments for an optical investiga- part of the international effort to understand tion of solar activity.
    [Show full text]
  • Cosmology from Antarctica Antony A
    Cosmology from Antarctica Antony A. Stark ABSTRACT. We are in a golden age of observational cosmology, where measurements of the universe have progressed from crude estimates to precise knowledge. Many of these observations are made from the Antarctic, where conditions are particularly favorable. When we use telescopes to look out at the distant universe, we are also looking back in time because the speed of light is finite. Looking out 13.7 billion years, the cosmic micro- wave background (CMB) comes from a time shortly after the big bang. The first attempt at CMB observations from the Antarctic plateau was an expedition to the South Pole in December 1986 by the Radio Physics Research group at Bell Laboratories. The measured sky noise and opacity were highly encouraging. In the austral summer of 1988–1989, three CMB groups participated in the “Cucumber” campaign, where a temporary summer- only site dedicated to CMB anisotropy measurements was set up 2 km from South Pole Sta- tion. Winter observations became possible with the establishment in 1990 of the Center for Astrophysical Research in Antarctica (CARA), a U.S. National Science Foundation Science and Technology Center, which developed year- round observing facilities in the “Dark Sector,” a section of Amundsen- Scott South Pole Station dedicated to astronomical observations. Scientists at CARA fielded several astronomical instruments: Antarctic Sub- millimeter Telescope and Remote Observatory (AST/RO), South Pole Infrared Explorer (SPIREX), White Dish, Python, Viper, Arcminute Cosmology Bolometer Array Receiver (ACBAR), and Degree- Angular Scale Interferometer (DASI). By 2001, data from CARA, together with Balloon Observations of Millimetric Extragalactic Radiation and Geophys- ics (BOOMERANG), a CMB experiment on a long- duration balloon launched from Mc- Murdo Station on the coast of Antarctica, showed clear evidence that the overall geometry of the universe is flat, as opposed to being open or closed.
    [Show full text]
  • Astronomy in Antarctica
    The Astronomy and Astrophysics Review (2011) DOI 10.1007/s00159-010-0032-2 REVIEWARTICLE Michael G. Burton Astronomy in Antarctica Received: 3 May 2010 c Springer-Verlag 2010 Abstract Antarctica provides a unique environment for astronomers to practice their trade. The cold, dry and stable air found above the high Antarctic plateau, as well as the pure ice below, offers new opportunities for the conduct of obser- vational astronomy across both the photon and the particle spectrum. The sum- mits of the Antarctic plateau provide the best seeing conditions, the darkest skies and the most transparent atmosphere of any earth-based observing site. Astro- nomical activities are now underway at four plateau sites: the Amundsen-Scott South Pole Station, Concordia Station at Dome C, Kunlun Station at Dome A and Fuji Station at Dome F, in addition to long duration ballooning from the coastal station of McMurdo, at stations run by the USA, France/Italy, China, Japan and the USA, respectively. The astronomy conducted from Antarctica includes op- tical, infrared, terahertz and sub-millimetre astronomy, measurements of cosmic microwave background anisotropies, solar astronomy, as well as high energy as- trophysics involving the measurement of cosmic rays, gamma rays and neutrinos. Antarctica is also the richest source of meteorites on our planet. An extensive range of site testing measurements have been made over the high plateau sites. In this article, we summarise the facets of Antarctica that are driving developments in astronomy there, and review the results of the site testing experiments undertaken to quantify those characteristics of the Antarctic plateau relevant for astronomical observation.
    [Show full text]
  • United States Antarctic Activities 2001-2002
    United States Antarctic Activities 2001-2002 This site fulfills the annual obligation of the United States of America as an Antarctic Treaty signatory to report its activities taking place in Antarctica. This portion details planned activities for July 2001 through June 2002. Modifications to these plans will be published elsewhere on this site upon conclusion of the 2001-2002 season. National Science Foundation Arlington, Virginia 22230 November 30, 2001 Information Exchange Under United States Antarctic Activities Articles III and VII(5) of the ANTARCTIC TREATY Introduction Organization and content of this site respond to articles III(1) and VII(5) of the Antarctic Treaty. Format is as prescribed in the Annex to Antarctic Treaty Recommendation VIII-6, as amended by Recommendation XIII-3. The National Science Foundation, an agency of the U.S. Government, manages and funds the United States Antarctic Program. This program comprises almost the totality of publicly supported U.S. antarctic activities—performed mainly by scientists (often in collaboration with scientists from other Antarctic Treaty nations) based at U.S. universities and other Federal agencies; operations performed by firms under contract to the Foundation; and military logistics by units of the Department of Defense. Activities such as tourism sponsored by private U.S. groups or individuals are included. In the past, some private U.S. groups have arranged their activities with groups in another Treaty nation; to the extent that these activities are known to NSF, they are included. Visits to U.S. Antarctic stations by non-governmental groups are described in Section XVI. This document is intended primarily for use as a Web-based file, but can be printed using the PDF option.
    [Show full text]
  • Arxiv:0707.1075V1 [Astro-Ph] 9 Jul 2007 Pole Station Reporting Science Results in the Parallel Sessions: One Neutrino Telescope, Icecube (K
    CMB FROM THE SOUTH POLE: PAST, PRESENT, AND FUTURE J.M. KOVAC and D. BARKATS California Institute of Technology, Department of Physics, 1200 E California Bd, MC 59-33, Pasadena, CA 91125 South Pole Station offers a unique combination of high, dry, stable conditions and well- developed support facilities. Over the past 20 years, a sequence of increasingly sophisticated CMB experiments at Pole have built on the experience of early pioneering efforts, producing a number of landmark contributions to the field. Telescopes at the South Pole were among the first to make repeated detections of degree-scale CMB temperature anisotropy and to map out the harmonic structure of its acoustic peaks. More recent achievements include the first detection of polarization of the CMB and the most precise measurements of the temperature power spectrum at small angular scales. New CMB telescopes at the South Pole are now mak- ing ultra-deep observations of the large-scale polarization of the CMB and of its secondary temperature anisotropies on arcminute scales. These two observing goals represent the current frontiers of CMB research, focused on constraining Inflation and the nature of Dark Energy. The South Pole now hosts an array of CMB observing platforms covering a wide range of angular scales and supporting very long integration times on the cleanest sky available, and thus should play an increasing role in pushing these frontiers of CMB research. 1 Introduction The bottom of the world is surprisingly well represented at this 6th Rencontres du Vietnam 2006, with four separate experiments sited at the U.S. National Science Foundation’s South arXiv:0707.1075v1 [astro-ph] 9 Jul 2007 Pole Station reporting science results in the parallel sessions: one neutrino telescope, IceCube (K.
    [Show full text]
  • United States Antarctic Activities 2003-2004
    United States Antarctic Activities 2003-2004 This site fulfills the annual obligation of the United States of America as an Antarctic Treaty signatory to report its activities taking place in Antarctica. This portion details planned activities for July 2003 through June 2004. Modifications to these plans will be published elsewhere on this site upon conclusion of the 2003-2004 season. National Science Foundation Arlington, Virginia 22230 November 30, 2003 Information Exchange Under United States Antarctic Activities Articles III and VII(5) of the ANTARCTIC TREATY Introduction Organization and content of this site respond to articles III(1) and VII(5) of the Antarctic Treaty. Format is as prescribed in the Annex to Antarctic Treaty Recommendation VIII-6, as amended by Recommendation XIII-3. The National Science Foundation, an agency of the U.S. Government, manages and funds the United States Antarctic Program. This program comprises almost the totality of publicly supported U.S. antarctic activities—performed mainly by scientists (often in collaboration with scientists from other Antarctic Treaty nations) based at U.S. universities and other Federal agencies; operations performed by firms under contract to the Foundation; and military logistics by units of the Department of Defense. Activities such as tourism sponsored by private U.S. groups or individuals are included. In the past, some private U.S. groups have arranged their activities with groups in another Treaty nation; to the extent that these activities are known to NSF, they are included. Visits to U.S. Antarctic stations by non-governmental groups are described in Section XVI. This document is intended primarily for use as a Web-based file, but can be printed using the PDF option.
    [Show full text]
  • Cosmology from Antarctica
    Cosmology from Antarctica Robert W. Wilson & Antony A. Stark Smithsonian Astrophysical Observatory, 60 Garden St., Cambridge, MA 02138 Abstract. Four hundred thousand years after the Big Bang, electrons and nuclei combined to form atoms for the first time, allowing a sea of photons to stream freely through a newly- transparent Universe. After billions of years, those photons, highly redshifted by the universal cosmic expansion, have become the Cosmic Microwave Background Radiation (CMB) we see coming from all directions today. Observation of the CMB is central to observational cosmology, and the Antarctic Plateau is an exceptionally good site for this work. The first attempt at CMB observations from the Plateau was an expedition to the South Pole in December 1986 by the Radio Physics Research group at Bell Laboratories. No CMB anisotropies were observed, but sky noise and opacity were measured. The results were sufficiently encouraging that in the Austral summer of 1988-1989, three CMB groups participated in the “Cucumber” campaign, where a temporary site dedicated to CMB anisotropy measurements was set up 2 km from South Pole Station. These were summer-only campaigns. Winter-time observations became possible with the establishment in 1990 of the Center for Astrophysical Research in Antarctica (CARA), a National Science Foundation Science and Technology Center. CARA developed year-round observing facilities in the “Dark Sector”, a section of Amundsen-Scott South Pole Station dedicated to astronomical observations. CARA scientists fielded several astronomical instruments: AST/RO, SPIREX, White Dish, Python, Viper, ACBAR, and DASI. By 2001, data from CARA, together with BOOMERANG, a CMB experiment on a long-duration balloon launched from McMurdo Station on the coast of Antarctica, showed clear evidence that the overall geometry of the Universe is flat, as opposed to being positively or negatively curved.
    [Show full text]
  • Anisotropies of the Cosmic Microwave Background 3
    IL NUOVO CIMENTO Vol. ?, N. ? ? Anisotropies of the Cosmic Microwave Background M. Bersanelli(1), D. Maino(1) and A. Mennella(2) (1) Universit´adegli Studi di Milano, Via Celoria 16, I-20133, Milano, Italy (2) CNR-IASF (Sez. di Milano), Via Bassini 15, I-20133, Milano, Italy Summary. — We review the present status of Cosmic Microwave Background (CMB) anisotropy observations and discuss the main related astrophysical issues, instrumental effects and data analysis techniques. We summarise the balloon-borne and ground-based experiments that, after COBE-DMR, yielded detection or significant upper limits to CMB fluctuations. A comparison of subsets of combined data indicates that the acoustic features observed today in the angular power spectrum are not dominated by undetected systematics. Pushing the accuracy of CMB anisotropy measurements to their ultimate limits represents one of the best opportunities for cosmology to develop into a precision science in the next decade. We discuss the forthcoming sub-orbital and space programs, as well as future prospects of CMB observations. PACS 98.80 – Cosmology. 1. – INTRODUCTION arXiv:astro-ph/0209215v2 27 Sep 2002 The Cosmic Microwave Background (CMB) radiation has played a central role in modern cosmology since the time of its discovery by Penzias and Wilson in 1965 [1]. The existence of a background of cold photons was predicted several years before by Gamow, Alpher and Herman [2, 3] following their assumption that primordial abundances were produced during an early phase dominated by thermal radiation. Traditionally, the CMB is considered one of the three observational pillars supporting the cosmological scenario of the Hot Big Bang, together with light elements primordial abundances (see, e.g., [4]) and the cosmic expansion [5].
    [Show full text]
  • Fidy Andriamanankasina Ramamonjisoa NON-CIRCULARITY of BEAMS in the CMB POLARIZATION POWER SPECTRUM ESTIMATION
    Fidy Andriamanankasina Ramamonjisoa NON-CIRCULARITY OF BEAMS IN THE CMB POLARIZATION POWER SPECTRUM ESTIMATION by Fidy Andriamanankasina Ramamonjisoa Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy School of Mathematics, Statistics & Computer Science University of KwaZulu-Natal November 2013 As the candidate’s supervisor I have approved this thesis for submission. Signed: Name: Subharthi Ray Date: Abstract Precise measurements of the Cosmic Microwave Background (CMB) anisotropies have been one of the foremost concerns in modern cosmology as it provides valuable information on the cosmology of the Universe. However, an accurate estimation of the CMB power spectrum faces many challenges as the CMB experiments sensitivity increases. Furthermore, for the polarization experiments, the precision of the measurements is complicated by the fact that the polarization signal is very faint compared to the measured total intensity and could be impossible to detect in the presence of high level of systematics. One of the most important source of errors in CMB polarization experiment is the beam non-circularity (asymmetry). In addition, the non-uniform and partial sky coverage resulting from the masking of the CMB foreground contaminants as well as point sources bias the estimation of the power spectrum. Consequently, a reasonable estima- tion of the power spectrum must account for, at least, the beam asymmetry and incomplete sky coverage. Accurate estimation of the angular power spectrum can be done using the standard optimal Maximum Likelihood (ML), although for high resolution CMB experiments with large data set this method is unfeasible due to the enormous computation time involved in the process.
    [Show full text]