The Extragalactic Distance Scale
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Stellar Populations of Bulges of Disc Galaxies in Clusters
Astronomical Science Stellar Populations of Bulges of Disc Galaxies in Clusters Lorenzo Morelli1, 5 brightness radial profile of large bulges is assembly. We present a photometric and Emanuela Pompei 2 well described by the de Vaucouleurs spectroscopic study of the bulge-domi- Alessandro Pizzella1 law, although this law can be drastically nated region of a sample of spiral galax- Jairo Méndez-Abreu1, 3 changed taking into account the small- ies in clusters. Our aim is to estimate the Enrico Maria Corsini1 scale inner structures, smoothed by the age and metallicity of the stellar popula- Lodovico Coccato 4 seeing in ground-based observations. tion and the efficiency and timescale of Roberto Saglia 4 Some bulges are rotationally-flattened the last episode of star formation in order Marc Sarzi 6 oblate spheroids with little or no anisot- to disentangle early rapid assembly from Francesco Bertola1 ropy. But, the intrinsic shape of a large late slow growth of bulges. fraction of early-type bulges is triaxial, as shown by the isophotal misalignment 1 Dipartimento di Astronomia, Università with respect to their host discs and non- Sample, photometry, and spectroscopy di Padova, Italy circular gas motions. The bulk of their 2 ESO stellar population formed between red- In order to simplify the interpretation of 3 INAF-Osservatorio Astronomico di shifts 3 and 5 (~ 12 Gyr ago) over a short the results, we selected a sample of disc Padova, Italy timescale. The enrichment of the inter- galaxies, which do not show any mor- 4 Max-Planck-Institut für Extraterres- stellar medium is strongly related to the phological signature of having undergone trische Physik, Garching, Germany time delay between type II and type Ia a recent interaction event. -
CO Multi-Line Imaging of Nearby Galaxies (COMING) IV. Overview Of
Publ. Astron. Soc. Japan (2018) 00(0), 1–33 1 doi: 10.1093/pasj/xxx000 CO Multi-line Imaging of Nearby Galaxies (COMING) IV. Overview of the Project Kazuo SORAI1, 2, 3, 4, 5, Nario KUNO4, 5, Kazuyuki MURAOKA6, Yusuke MIYAMOTO7, 8, Hiroyuki KANEKO7, Hiroyuki NAKANISHI9 , Naomasa NAKAI4, 5, 10, Kazuki YANAGITANI6 , Takahiro TANAKA4, Yuya SATO4, Dragan SALAK10, Michiko UMEI2 , Kana MOROKUMA-MATSUI7, 8, 11, 12, Naoko MATSUMOTO13, 14, Saeko UENO9, Hsi-An PAN15, Yuto NOMA10, Tsutomu, T. TAKEUCHI16 , Moe YODA16, Mayu KURODA6, Atsushi YASUDA4 , Yoshiyuki YAJIMA2 , Nagisa OI17, Shugo SHIBATA2, Masumichi SETA10, Yoshimasa WATANABE4, 5, 18, Shoichiro KITA4, Ryusei KOMATSUZAKI4 , Ayumi KAJIKAWA2, 3, Yu YASHIMA2, 3, Suchetha COORAY16 , Hiroyuki BAJI6 , Yoko SEGAWA2 , Takami TASHIRO2 , Miho TAKEDA6, Nozomi KISHIDA2 , Takuya HATAKEYAMA4 , Yuto TOMIYASU4 and Chey SAITA9 1Department of Physics, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan 2Department of Cosmosciences, Graduate School of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan 3Department of Physics, School of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan 4Division of Physics, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan 5Tomonaga Center for the History of the Universe (TCHoU), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan 6Department of Physical Science, Osaka Prefecture University, Gakuen 1-1, -
Distances to Local Group Galaxies
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server Distances to Local Group Galaxies Alistair R. Walker Cerro Tololo Inter-American Observatory, NOAO, Casilla 603, la Serena, Chile Abstract. Distances to galaxies in the Local Group are reviewed. In particular, the distance to the Large Magellanic Cloud is found to be (m M)0 =18:52 0:10, cor- − ± responding to 50; 600 2; 400 pc. The importance of M31 as an analog of the galaxies observed at greater distances± is stressed, while the variety of star formation and chem- ical enrichment histories displayed by Local Group galaxies allows critical evaluation of the calibrations of the various distance indicators in a variety of environments. 1 Introduction The Local Group (hereafter LG) of galaxies has been comprehensively described in the monograph by Sidney van den Berg [1], with update in [2]. The zero- velocity surface has radius of a little more than 1 Mpc, therefore the small sub-group of galaxies consisting of NGC 3109, Antlia, Sextans A and Sextans B lie outside the the LG by this definition, as do galaxies in the direction of the nearby Sculptor and IC342/Maffei groups. Thus the LG consists of two large spirals (the Galaxy and M31) each with their entourage of 11 and 10 smaller galaxies respectively, the dwarf spiral M33, and 13 other galaxies classified as either irregular or spherical. We have here included NGC 147 and NGC 185 as members of the M31 sub-group [60], whether they are actually bound to M31 is not proven. -
Analysis of New High-Precision Transit Light Curves of WASP-10 B: Starspot
Astronomy & Astrophysics manuscript no. wasp10 c ESO 2018 September 10, 2018 Analysis of new high-precision transit light curves of WASP-10 b: starspot occultations, small planetary radius, and high metallicity⋆ G. Maciejewski1,2, St. Raetz2, N.Nettelmann3, M. Seeliger2, Ch. Adam2, G. Nowak1, and R. Neuh¨auser2 1 Toru´nCentre for Astronomy, Nicolaus Copernicus University, Gagarina 11, PL–87100 Toru´n, Poland e-mail: [email protected] 2 Astrophysikalisches Institut und Universit¨ats-Sternwarte, Schillerg¨asschen 2–3, D–07745 Jena, Germany 3 Institut f¨ur Physik, Universit¨at Rostock, D–18051 Rostock, Germany Received ...; accepted ... ABSTRACT Context. The WASP-10 planetary system is intriguing because different values of radius have been reported for its transiting exoplanet. The host star exhibits activity in terms of photometric variability, which is caused by the rotational modulation of the spots. Moreover, a periodic modulation has been discovered in transit timing of WASP-10 b, which could be a sign of an additional body perturbing the orbital motion of the transiting planet. Aims. We attempt to refine the physical parameters of the system, in particular the planetary radius, which is crucial for studying the internal structure of the transiting planet. We also determine new mid-transit times to confirm or refute observed anomalies in transit timing. Methods. We acquired high-precision light curves for four transits of WASP-10 b in 2010. Assuming various limb-darkening laws, we generated best-fit models and redetermined parameters of the system. The prayer-bead method and Monte Carlo simulations were used to derive error estimates. -
A Hot Subdwarf-White Dwarf Super-Chandrasekhar Candidate
A hot subdwarf–white dwarf super-Chandrasekhar candidate supernova Ia progenitor Ingrid Pelisoli1,2*, P. Neunteufel3, S. Geier1, T. Kupfer4,5, U. Heber6, A. Irrgang6, D. Schneider6, A. Bastian1, J. van Roestel7, V. Schaffenroth1, and B. N. Barlow8 1Institut fur¨ Physik und Astronomie, Universitat¨ Potsdam, Haus 28, Karl-Liebknecht-Str. 24/25, D-14476 Potsdam-Golm, Germany 2Department of Physics, University of Warwick, Coventry, CV4 7AL, UK 3Max Planck Institut fur¨ Astrophysik, Karl-Schwarzschild-Straße 1, 85748 Garching bei Munchen¨ 4Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106, USA 5Texas Tech University, Department of Physics & Astronomy, Box 41051, 79409, Lubbock, TX, USA 6Dr. Karl Remeis-Observatory & ECAP, Astronomical Institute, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Sternwartstr. 7, 96049 Bamberg, Germany 7Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA 8Department of Physics and Astronomy, High Point University, High Point, NC 27268, USA *[email protected] ABSTRACT Supernova Ia are bright explosive events that can be used to estimate cosmological distances, allowing us to study the expansion of the Universe. They are understood to result from a thermonuclear detonation in a white dwarf that formed from the exhausted core of a star more massive than the Sun. However, the possible progenitor channels leading to an explosion are a long-standing debate, limiting the precision and accuracy of supernova Ia as distance indicators. Here we present HD 265435, a binary system with an orbital period of less than a hundred minutes, consisting of a white dwarf and a hot subdwarf — a stripped core-helium burning star. -
The Young Stellar Population of IC 1613 III
A&A 551, A74 (2013) Astronomy DOI: 10.1051/0004-6361/201219977 & c ESO 2013 Astrophysics The young stellar population of IC 1613 III. New O-type stars unveiled by GTC-OSIRIS,, M. Garcia1,2 and A. Herrero1,2 1 Instituto de Astrofísica de Canarias, C/Vía Láctea s/n, 38200 La Laguna, Tenerife, Spain e-mail: [email protected] 2 Departamento de Astrofísica, Universidad de La Laguna, Avda. Astrofísico Francisco Sánchez, s/n, 38071 La Laguna, Tenerife, Spain Received 9 July 2012 / Accepted 16 November 2012 ABSTRACT Context. Very low-metallicity massive stars are key to understanding the reionization epoch. Radiation-driven winds, chief agents in the evolution of massive stars, are consequently an important ingredient in our models of the early-Universe. Recent findings hint that the winds of massive stars with poorer metallicity than the SMC may be stronger than predicted by theory. Besides calling the paradigm of radiation-driven winds into question, this result would affect the calculated ionizing radiation and mechanical feedback of massive stars, as well as the role these objects play at different stages of the Universe. Aims. The field needs a systematic study of the winds of a large sample of very metal-poor massive stars. The sampling of spectral types is particularly poor in the very early types. This paper’s goal is to increase the list of known O-type stars in the dwarf irregular galaxy IC 1613, whose metallicity is lower than the SMC’s roughly by a factor 2. Methods. Using the reddening-free Q pseudo-colour, evolutionary masses, and GALEX photometry, we built a list of very likely O-type stars. -
October 2006
OCTOBER 2 0 0 6 �������������� http://www.universetoday.com �������������� TAMMY PLOTNER WITH JEFF BARBOUR 283 SUNDAY, OCTOBER 1 In 1897, the world’s largest refractor (40”) debuted at the University of Chica- go’s Yerkes Observatory. Also today in 1958, NASA was established by an act of Congress. More? In 1962, the 300-foot radio telescope of the National Ra- dio Astronomy Observatory (NRAO) went live at Green Bank, West Virginia. It held place as the world’s second largest radio scope until it collapsed in 1988. Tonight let’s visit with an old lunar favorite. Easily seen in binoculars, the hexagonal walled plain of Albategnius ap- pears near the terminator about one-third the way north of the south limb. Look north of Albategnius for even larger and more ancient Hipparchus giving an almost “figure 8” view in binoculars. Between Hipparchus and Albategnius to the east are mid-sized craters Halley and Hind. Note the curious ALBATEGNIUS AND HIPPARCHUS ON THE relationship between impact crater Klein on Albategnius’ southwestern wall and TERMINATOR CREDIT: ROGER WARNER that of crater Horrocks on the northeastern wall of Hipparchus. Now let’s power up and “crater hop”... Just northwest of Hipparchus’ wall are the beginnings of the Sinus Medii area. Look for the deep imprint of Seeliger - named for a Dutch astronomer. Due north of Hipparchus is Rhaeticus, and here’s where things really get interesting. If the terminator has progressed far enough, you might spot tiny Blagg and Bruce to its west, the rough location of the Surveyor 4 and Surveyor 6 landing area. -
Not Surprising That the Method Begins to Break Down at This Point
152 ASTRONOMY: W. S. ADAMS hanced lines in the early F stars are normally so prominent that it is not surprising that the method begins to break down at this point. To illustrate the use of the formulae and curves we may select as il- lustrations a few stars of different spectral types and magnitudes. These are collected in Table II. The classification is from Mount Wilson determinations. TABLE H ~A M PARAIuAX srTATYP_________________ (a) I(b) (C) (a) (b) c) Mean Comp. Ob. Pi 10U96.... 7.6F5 -0.7 +0.7 +3.0 +6.5 4.7 5.8 5.7 +0#04 +0.04 Sun........ GO -0.5 +0.5 +3.0 +5.6 4.3 5.8 5.2 Lal. 38287.. 7.2 G5 -1.8 +1.5 +3.5 +7.4 +6.3 +6.2 7.3 +0.10 +0.09 a Arietis... 2.2K0O +2.5 -2.4 +0.2 +1.0 1.3 +0.2 0.8 +0.05 +0.09 aTauri.... 1.1K5 +3.0 -2.0 +0.5 -0.4 +1.9 +0.5 0.7 +0.08 +0.07 61' Cygni...6.3K8 -1.8 +5.8 +7.7 +8.2 9.3 8.9 8.8 +0.32 +0.31 Groom. 34..8.2 Ma -2.2 +6.8 +9.2 +10.2 10.5 10.4 10.4 +0.28 +0.28 The parallaxes are computed from the absolute magnitudes by the formula, to which reference has already been made, 5 logr = M - m - 5. The results are given in the next to the last column of the table, and the measured parallaxes in the final column. -
The Properties of Ten O-Type Stars in the Low-Metallicity Galaxies IC 1613, WLM, and NGC 3109?
A&A 572, A36 (2014) Astronomy DOI: 10.1051/0004-6361/201424312 & c ESO 2014 Astrophysics The properties of ten O-type stars in the low-metallicity galaxies IC 1613, WLM, and NGC 3109? F. Tramper1, H. Sana2, A. de Koter1;3, L. Kaper1, and O. H. Ramírez-Agudelo1 1 Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, PO Box 94249, 1090 GE Amsterdam, The Netherlands e-mail: [email protected] 2 ESA/Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 3 Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium Received 30 May 2014 / Accepted 30 September 2014 ABSTRACT Context. Massive stars likely played an important role in the reionization of the Universe, and the formation of the first black holes. They are potential progenitors of long-duration gamma-ray bursts, seen up to redshifts of about ten. Massive stars in low-metallicity environments in the local Universe are reminiscent of their high redshift counterparts, emphasizing the importance of the study of their properties and evolution. In a previous paper, we reported on indications that the stellar winds of low-metallicity O stars may be stronger than predicted, which would challenge the current paradigm of massive star evolution. Aims. In this paper, we aim to extend our initial sample of six O stars in low-metallicity environments by four. The total sample of ten stars consists of the optically brightest sources in IC 1613, WLM, and NGC 3109. We aim to derive their stellar and wind parameters, and compare these to radiation-driven wind theory and stellar evolution models. -
Jason A. Dittmann 51 Pegasi B Postdoctoral Fellow
Jason A. Dittmann 51 Pegasi b Postdoctoral Fellow Contact Massachusetts Institute of Technology MIT Kavli Institute: 37-438f 617-258-5928 (office) 70 Vassar St. 520-820-0928 (cell) Cambridge, MA 02139 [email protected] Education Harvard University, Cambridge, MA PhD, Astronomy and Astrophysics, May 2016 Advisor: David Charbonneau, PhD • University of Arizona, Tucson, AZ BS, Astronomy, Physics, May 2010 Advisor: Laird Close, PhD • Recent 51 Pegasi b Postdoctoral Fellow July 2017 – Present Research Earth and Planetary Science Department, MIT Positions Faculty Contact: Sara Seager Postdoctoral Researcher Feb 2017 – June 2017 Kavli Institute, MIT Supervisor: Sarah Ballard Postdoctoral Researcher July 2016 – Jan 2017 Center for Astrophysics, Harvard University Supervisor: David Charbonneau Research Assistant Sep 2010 – May 2016 Center for Astrophysics, Harvard University Advisors: David Charbonneau Publication 16 first and second authored publications Summary 22 additional co-authored publications 1 first-authored publication in Nature 1 co-authored publication in Nature Selected 51 Pegasi b Postdoctoral Fellowship 2017 – Present Awards and Pierce Fellowship 2010 – 2013 Honors Certificate of Distinction in Teaching 2012 Best Project Award, Physics Ugrd. Research Symp. 2009 Best Undergraduate Research (Steward Observatory) 2009 – 2010 Grants Principal Investigator, Hubble Space Telescope 2017, 10 orbits Awarded “Initial Reconaissance of a Transiting Rocky (maximum award) Planet in a Nearby M-Dwarf’s Habitable Zone” Principal Investigator, -
The Stellar Populacons of IC 10 and NGC 1569 Observed with Keck
The Stellar Populaons of IC 10 and NGC 1569 observed with Keck LGSAO and HST William D. Vacca (USRA‐SOFIA) Chris Sheehy James Graham (UC Berkeley) Nate McCrady (UCLA) Properes of IC 10 • Small irregular starburst (BCD) galaxy on outskirts of Local Group – R ~ 1 kpc 9 – M ~ 1‐2 x 10 M • Low metallicity (Z ~ 0.2‐0.3 Z~ ZSMC) • Brief, galaxy‐wide burst of SF occurred within last 10 Myr – Numerous HII regions – Large Hα and FIR luminosity ‐1 • Highest SFR of any LG dwarf (> 0.7 M yr ) – Large populaon of W‐R stars (NWR > 24; SMC has ~ 8) • Highest surface density of W‐Rs in LG ( ~ 8 kpc‐2; MW ~ 2.5 kpc‐2) • Anomalously high WC/WN rao ( ~ 1‐2) for its Z (10x too large!) • Have WN stars been missed in surveys? • b = −3.3° – Uncertain reddening: AV = 1.2 – 6.0 mag – Uncertain distance: D = 0.5 – 3.0 Mpc • Ideal extragalacc target for NIR observaons with LGSAO – Nearby, relavely large AV (foreground and internal), high ρ★ – Bright p‐lt guide stars available N IC 10 HST/ACS/WFC F435W, F606W, F814W 1” ≈ 4 pc WR Object: [MAC92] 24 • Brightest W‐R candidate in HST/WFPC2 F555W IC10 • Lies within prominent H II region HL 111c • Lies at center of a young stellar cluster (Hunter 2001) • Uncertain spectral type 5’’ – Weak, broad He II 4686 emission (Massey & Holmes 2002) – WN+OB? • Three components (A, B, C) • Cluster itself? Crowther et al. (2003) Observaons • NIR Data: • Opcal Data: – NIRC2/Keck II/LGSAO H and K’ – HST/ACS/WFC F814W – 0.01”pixel‐1 – 0.05”pixel‐1 – Final FOV = 12.2” x 12.2” – texp = 1080 s – texp = 1200 s (H); 1500 s (K’) – FWHM = 0.08” – FWHM = 0.048” (H); 0.051” (K’) – Strehl ~ 18% (H); 32% (K’) ACS WFC / NIRC2 Comparison HST/ACS/WFC F814W Keck II/NIRC2/LGSAO K’ IC 10 IHK’ N E 12.2” x 12.2” 47 pc x 47 pc Vacca, Sheehy, & Graham (2007) CMD of IC 10 [MAC92] 24 Region Opcal Data: • PSF fing (Anderson & King 2006) • 690 stars found in F814W • [F814W]Lim ~ 25.25 • σ < 0.04 mag for [F814W] < 23.0 NIR Data: • MTF‐fing method (Sheehy et al. -
IAU Division C Working Group on Star Names 2019 Annual Report
IAU Division C Working Group on Star Names 2019 Annual Report Eric Mamajek (chair, USA) WG Members: Juan Antonio Belmote Avilés (Spain), Sze-leung Cheung (Thailand), Beatriz García (Argentina), Steven Gullberg (USA), Duane Hamacher (Australia), Susanne M. Hoffmann (Germany), Alejandro López (Argentina), Javier Mejuto (Honduras), Thierry Montmerle (France), Jay Pasachoff (USA), Ian Ridpath (UK), Clive Ruggles (UK), B.S. Shylaja (India), Robert van Gent (Netherlands), Hitoshi Yamaoka (Japan) WG Associates: Danielle Adams (USA), Yunli Shi (China), Doris Vickers (Austria) WGSN Website: https://www.iau.org/science/scientific_bodies/working_groups/280/ WGSN Email: [email protected] The Working Group on Star Names (WGSN) consists of an international group of astronomers with expertise in stellar astronomy, astronomical history, and cultural astronomy who research and catalog proper names for stars for use by the international astronomical community, and also to aid the recognition and preservation of intangible astronomical heritage. The Terms of Reference and membership for WG Star Names (WGSN) are provided at the IAU website: https://www.iau.org/science/scientific_bodies/working_groups/280/. WGSN was re-proposed to Division C and was approved in April 2019 as a functional WG whose scope extends beyond the normal 3-year cycle of IAU working groups. The WGSN was specifically called out on p. 22 of IAU Strategic Plan 2020-2030: “The IAU serves as the internationally recognised authority for assigning designations to celestial bodies and their surface features. To do so, the IAU has a number of Working Groups on various topics, most notably on the nomenclature of small bodies in the Solar System and planetary systems under Division F and on Star Names under Division C.” WGSN continues its long term activity of researching cultural astronomy literature for star names, and researching etymologies with the goal of adding this information to the WGSN’s online materials.