DOCSLIB.ORG

Properties of Members of Stellar Kinematic Groups and Stars with Circumstellar Dusty Debris Discs

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Properties of Members of Stellar Kinematic Groups and Stars with Circumstellar Dusty Debris Discs UNIVERSIDAD AUTONOMA´ DE MADRID Facultad de Ciencias Departamento de F´ısica Teorica´ A spectroscopic study of the nearby late-type stellar population: Properties of members of stellar kinematic groups and stars with circumstellar dusty debris discs. PhD dissertation submitted by Jesus´ Maldonado Prado for the degree of Doctor in Physics Supervised by Dr. Carlos Eiroa de San Francisco Madrid, June 2012 UNIVERSIDAD AUTONOMA´ DE MADRID Facultad de Ciencias Departamento de F´ısica Teorica´ Estudio espectroscopico´ de la poblacion´ estelar fr´ıa cercana: Propiedades de estrellas en grupos cinematicos´ estelares y de estrellas con discos circunestelares de tipo debris. Memoria de tesis doctoral presentada por Jesus´ Maldonado Prado para optar al grado de Doctor en Ciencias F´ısicas Trabajo dirigido por el Dr. Carlos Eiroa de San Francisco Madrid, Junio de 2012 A mis padres y hermanos Agradecimientos La finalizaci´on de una tesis doctoral es siempre un momento para el balance y la reflexi´on. Conf´ıo que estas breves palabras sirvan de peque˜no reconocimiento a todas las personas que durante todo este largo, y no siempre f´acil, per´ıodo de tiempo han tenido a bien brindarme su ayuda, su apoyo y, en muchos casos, su simpat´ıa. A todos los que de alguna manera me habe´ıs ayudado, gracias. Las primeras palabras de estas notas deben ser para mi supervisor de tesis, Carlos Eiroa, por su confianza, su apoyo y dedicaci´on y sobre todo por esa mi- rada cr´ıtica tan suya que, desde siempre, ha tratado de transmitirme. A Benjam´ın Montesinos debo agradecerle muchas cosas, en particular su cercan´ıa y su forma de ser, a David Montes y a Raquel Mart´ınez, su esfuerzo y dedicaci´on. A Alcione Mora y a Eva Villaver quisiera agradecerles su confianza, sus consejos y lo mucho que he disfrutado trabajando con ellos. A lo largo de estos a˜nos he tenido la oportunidad de conocer y trabajar con mucha gente, de todos ellos he aprendido y con todos ellos he compartido buenas experiencias, en especial, Jonathan Marsall, Amelia Bayo, Gwendolyn Meeus, Alexander Mustill, Aurora Sicilia, todos los “DUNERs” y, por supuesto, Ignacio Mendigut´ıa con el que llevo tantos a˜nos compartiendo amistad. En especial, a Ralf Lahunhardt debo agradecerle la estancia que hice en Heidelberg y su ayuda con los espectros FEROS. Quisiera igualmente mencionar a mis amigos y compa˜neros del 301, al per- sonal del departamento de F´ısica Te´orica, de la Universidad Aut´onoma de Madrid, y de los observatorios de Calar Alto y La Palma, as´ıcomo a todos mis amigos en Bola˜nos, en Madrid y en otros muchos sitios. Las palabras m´as importantes, como casi siempre suele ocurrir, se dejan para el final y, como no puede ser de otra manera, han de ser para mi familia, mis padres y mis hermanos, porque me han querido, me han animado, han cuidado de m´ıdesde peque˜n´ıto y siempre han dado todo lo que tienen (e incluso lo que no tienen) por m´ı. Jes´us Maldonado Prado vii Acknowledgements This Ph.D. Thesis is based on observations made with the 2.2 m telescope at the Centro Astronomico´ Hispano-Aleman´ (CAHA) at Calar Alto (Spain), operated jointly by the Max-Planck Institute f¨ur Astronomie and the Instituto de Astrof´ısica de Andaluc´ıa (CSIC); the Italian Telescopio Nazionale Galileo (TNG), operated on the island of La Palma by the Fundaci´on Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrof´ısica de Canarias; and the Nordic Optical Telescope (NOT), operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrof´ısica de Canarias. Complementary data has also been taken from the ESO Science Archive facility at http:://archive.eso.org/cms/. This work has been supported by the Spanish Ministerio de Ciencia e Inno- vaci´on (MICINN), Programa Nacional de Formaci´on de Personal Investigador FPI 2006, and Plan Nacional de Astronom´ıa y Astrof´ısica, under projects AYA2005- 00954, and AYA2008-01727. The author also acknowledges support from the Department of Theoretical Physics of the Universidad Aut´onoma de Madrid, via an assistant teacher position. Additional funding for the Comunidad de Madrid project ASTRID S-0505/ESP/00361 is acknowledged. This research has made use of the SIMBAD database and the VizieR catalogue access tool both operated at CDS, Strasbourg, France. The Spanish Virtual Obser- vatory team is acknowledged for the development of the DAMA (Darwin Archive MAdrid) and DUNES Virtual Observatory Tools. This research also made use of the NASA’s Astrophysics Data System Bibliographic Services. ix Abstract Understanding how stars and planetary systems form and evolve is one of the major goals of modern Astrophysics. Given that their stellar properties resemble those of our Sun, main-sequence, late-type stars usually constitute primary tar- gets in exo-planet search programs, as well as surveys seeking for dusty debris discs similar to the Solar System’s zodiacal light and the Edgeworth Kuiper Belt. Nearby stars have the additional advantage that high-resolution observations can be obtained for large samples, allowing a precise determination of their properties. In this dissertation, the results of a high-resolution (λ/∆λ ∼ 57000), optical spectra study of a sample of nearby (distance less than 25 pc), main-sequence, late-type (spectral type FGK) stars are presented. The specific objective of this project is the spectroscopic characterisation of the nearby late-type stellar population, in particular the stars hosting debris discs. In order to analyse the temporal evolution of debris discs, stellar ages as ac- curate as possible are required. However, stellar age is one of the most difficult parameters to determine, in particular for solar-type field stars. Therefore, in the first part of this dissertation a comparison between different methods to derive ages is performed. Young stars are identified on the basis of their kinematics and plausible membership to stellar kinematic groups. Radial velocities are derived by using the cross-correlation technique and galactic spatial-velocity components (U, V, W) are computed. The young nature of the candidates selected by their kine- matics is confirmed or rejected by analysing their lithium abundances, rotation periods, and levels of chromospheric and coronal emission. Our results show that roughly 25% of the stars analysed show a kinematics in agreement with some of the known kinematic groups. Nevertheless, when age diagnostics are considered, most of these stars are too old to be members of kinematic groups, and only 25.5% of the candidates (6.5% of the total stars) can be considered as probable members of a kinematic group. The results of this study are published by Maldonado et al. (2010, Chapter 3). In the second part of this dissertation, we study whether the presence or ab- sence of debris discs correlate with the stellar properties of the host stars, in par- ticular with the stellar age and metallicity, since the presence of planets (giant- planets) is known to correlate with the metal content of the host star. Fundamental stellar parameters, Teff, log g, and [Fe/H] are calculated by measuring the equiva- lent width of a sample of isolated Fe I and Fe II lines and applying the iron excita- tion and ionisation equilibrium conditions. Data from the literature for those stars with debris disc not included in our spectroscopic observations are also used. We have found a smooth transition toward higher metallicities from stars with neither debris disc nor planets to stars hosting giant-planets. Stars with debris discs show a similar metallicity distribution to that of stars without discs. Stars harbouring xi ABSTRACT both debris discs and planets show the same metallicity behaviour as stars hosting planets. These results can be explained by core-accretion models of planet for- mation. In addition, we have also found that planets orbiting around stars with debris discs are usually cool. The data suggest that stars hosting debris and gas- giant planets tend to have low-dust luminosities, and that there seems to be an anticorrelation between the dust luminosity and the innermost planet eccentricity. These trends could be explained by recent simulations of dynamical instabilities produced by eccentric giant planets. This study is published by Maldonado et al. (2012, Chapter 4). The confirmation or rejection of the apparent trends suggested in Chapter 4 requires the analysis of extended samples, i.e., the detection of new debris discs around stars with planets. The possibility of finding colder and fainter debris discs using the new capabilities offered by the Herschel Space Telescope is discussed in Chapter 5. This work was motivated as a preparatory activity for the DUNES (DUst around NEarby Stars, Principal Investigator: Carlos Eiroa) project, a Her- schel Open Time Key Project aimed to detect circumstellar debris discs with IR excesses as low as the one of the Edgeworth-Kuiper belt. The work addresses how stellar photospheres are predicted at far-IR wavelengths, analysing the differ- ent sources of uncertainties and their influence in the detection of a debris discs: i) choice of the stellar atmosphere model (ATLAS9, PHOENIX, MARCS); ii) stellar parameters; and iii) choice of the photometric points used to match the models with the observed spectral energy distribution. This work played a central role to accurately fix the exposure time of each of the DUNES targets, achieving a compromise between the exposure time of each target and optimising, as much as possible, the total observing time granted for DUNES.
Load more

Recommended publications
  • Evidence for Very Extended Gaseous Layers Around O-Rich Mira Variables and M Giants B
    The Astrophysical Journal, 579:446–454, 2002 November 1 # 2002. The American Astronomical Society. All rights reserved. Printed in U.S.A. EVIDENCE FOR VERY EXTENDED GASEOUS LAYERS AROUND O-RICH MIRA VARIABLES AND M GIANTS B. Mennesson,1 G. Perrin,2 G. Chagnon,2 V. Coude du Foresto,2 S. Ridgway,3 A. Merand,2 P. Salome,2 P. Borde,2 W. Cotton,4 S. Morel,5 P. Kervella,5 W. Traub,6 and M. Lacasse6 Received 2002 March 15; accepted 2002 July 3 ABSTRACT Nine bright O-rich Mira stars and five semiregular variable cool M giants have been observed with the Infrared and Optical Telescope Array (IOTA) interferometer in both K0 (2.15 lm) and L0 (3.8 lm) broad- band filters, in most cases at very close variability phases. All of the sample Mira stars and four of the semire- gular M giants show strong increases, from ’20% to ’100%, in measured uniform-disk (UD) diameters between the K0 and L0 bands. (A selection of hotter M stars does not show such a large increase.) There is no evidence that K0 and L0 broadband visibility measurements should be dominated by strong molecular bands, and cool expanding dust shells already detected around some of these objects are also found to be poor candi- dates for producing these large apparent diameter increases. Therefore, we propose that this must be a con- tinuum or pseudocontinuum opacity effect. Such an apparent enlargement can be reproduced using a simple two-component model consisting of a warm (1500–2000 K), extended (up to ’3 stellar radii), optically thin ( ’ 0:5) layer located above the classical photosphere.
    [Show full text]
  • Messier Objects
    Messier Objects From the Stocker Astroscience Center at Florida International University Miami Florida The Messier Project Main contributors: • Daniel Puentes • Steven Revesz • Bobby Martinez Charles Messier • Gabriel Salazar • Riya Gandhi • Dr. James Webb – Director, Stocker Astroscience center • All images reduced and combined using MIRA image processing software. (Mirametrics) What are Messier Objects? • Messier objects are a list of astronomical sources compiled by Charles Messier, an 18th and early 19th century astronomer. He created a list of distracting objects to avoid while comet hunting. This list now contains over 110 objects, many of which are the most famous astronomical bodies known. The list contains planetary nebula, star clusters, and other galaxies. - Bobby Martinez The Telescope The telescope used to take these images is an Astronomical Consultants and Equipment (ACE) 24- inch (0.61-meter) Ritchey-Chretien reflecting telescope. It has a focal ratio of F6.2 and is supported on a structure independent of the building that houses it. It is equipped with a Finger Lakes 1kx1k CCD camera cooled to -30o C at the Cassegrain focus. It is equipped with dual filter wheels, the first containing UBVRI scientific filters and the second RGBL color filters. Messier 1 Found 6,500 light years away in the constellation of Taurus, the Crab Nebula (known as M1) is a supernova remnant. The original supernova that formed the crab nebula was observed by Chinese, Japanese and Arab astronomers in 1054 AD as an incredibly bright “Guest star” which was visible for over twenty-two months. The supernova that produced the Crab Nebula is thought to have been an evolved star roughly ten times more massive than the Sun.
    [Show full text]
  • Naming the Extrasolar Planets
    Naming the extrasolar planets W. Lyra Max Planck Institute for Astronomy, K¨onigstuhl 17, 69177, Heidelberg, Germany [email protected] Abstract and OGLE-TR-182 b, which does not help educators convey the message that these planets are quite similar to Jupiter. Extrasolar planets are not named and are referred to only In stark contrast, the sentence“planet Apollo is a gas giant by their assigned scientific designation. The reason given like Jupiter” is heavily - yet invisibly - coated with Coper- by the IAU to not name the planets is that it is consid- nicanism. ered impractical as planets are expected to be common. I One reason given by the IAU for not considering naming advance some reasons as to why this logic is flawed, and sug- the extrasolar planets is that it is a task deemed impractical. gest names for the 403 extrasolar planet candidates known One source is quoted as having said “if planets are found to as of Oct 2009. The names follow a scheme of association occur very frequently in the Universe, a system of individual with the constellation that the host star pertains to, and names for planets might well rapidly be found equally im- therefore are mostly drawn from Roman-Greek mythology. practicable as it is for stars, as planet discoveries progress.” Other mythologies may also be used given that a suitable 1. This leads to a second argument. It is indeed impractical association is established. to name all stars. But some stars are named nonetheless. In fact, all other classes of astronomical bodies are named.
    [Show full text]
  • WASP Page 1 Hubble Eyes Aging Stars Science News, Vol. 148
    WASP Warren Astronomical Society Paper Volume 27, number 11 $1.00 for non-members November 1995 DATING THE COSMOS COMPUTER CHATTER ANNUAL HOLIDAY AWARDS Hubble eyes aging stars Larry F. Kalinowski Science News, Vol. 148, September 2,1995 submitted by Lorna Simmons Everyone knows you can't be older than your mother. But over the past year, observations with the Hubble Space Telescope and several other Comet DeVico has just passed perihelion in instruments seem to have contradicted this cardi- early October, so its beginning to fade from its maxi- nal rule. On the one hand, measurements of the mum brightness of 5.6. It was recovered in its seventy- speed at which the most distant galaxies are mov- four year orbit by independent comet observers Naka- ing from Earth suggest that the universe may be mura, Tanaka and Utsunomiya. It becomes a sixth no older than 8 billion to 12 billion years (SN: magnitude object on the night of the Macomb meeting, 10/8;94, p.232). On the other hand, astronomers October 19. Early reports say it has two tails. A morn- ing object, only, about fifteen degrees above the hori- estimate he ages of our galaxy's oldest stars at zon before twilight begins, it's easily observed as it 13 billion to 16 billion years. leaves Leo and enters the Ursa Major-Coma Berenices Now, new findings from Hubble may provide a area of the sky. However, it is quickly moving closer to step toward resolving this cosmic conundrum. the horizon and will become increasingly more difficult In viewing the globular cluster M4, the dense to observe during the rest of the month.
    [Show full text]
  • Australian Sky & Telescope
    TRANSIT MYSTERY Strange sights BINOCULAR TOUR Dive deep into SHOOT THE MOON Take amazing as Mercury crosses the Sun p28 Virgo’s endless pool of galaxies p56 lunar images with your smartphone p38 TEST REPORT Meade’s 25-cm LX600-ACF P62 THE ESSENTIAL MAGAZINE OF ASTRONOMY Lasers and advanced optics are transforming astronomy p20 HOW TO BUY THE RIGHT ASTRO CAMERA p32 p14 ISSUE 93 MAPPING THE BIG BANG’S COSMIC ECHOES $9.50 NZ$9.50 INC GST LPI-GLPI-G LUNAR,LUNAR, PLANETARYPLANETARY IMAGERIMAGER ANDAND GUIDERGUIDER ASTROPHOTOGRAPHY MADE EASY. Let the LPI-G unleash the inner astrophotographer in you. With our solar, lunar and planetary guide camera, experience the universe on a whole new level. 0Image Sensor:'+(* C O LOR 0 Pixel Size / &#*('+ 0Frames per second/Resolution• / • / 0 Image Format: #,+$)!&))'!,# .# 0 Shutter%,*('#(%%#'!"-,,* 0Interface: 0Driver: ASCOM compatible 0GuiderPort: 0Color or Monochrome Models (&#'!-,-&' FEATURED DEALERS: MeadeTelescopes Adelaide Optical Centre | www.adelaideoptical.com.au MeadeInstrument The Binocular and Telescope Shop | www.bintel.com.au MeadeInstruments www.meade.com Sirius Optics | www.sirius-optics.com.au The device to free you from your handbox. With the Stella adapter, you can wirelessly control your GoTo Meade telescope at a distance without being limited by cord length. Paired with our new planetarium app, *StellaAccess, astronomers now have a graphical interface for navigating the night sky. STELLA WI-FI ADAPTER / $#)'$!!+#!+ #$#)'#)$##)$#'&*' / (!-')-$*')!($%)$$+' "!!$#$)(,#%',).( StellaAccess app. Available for use on both phones and tablets. /'$+((()$!'%!#)'*")($'!$)##!'##"$'$*) stars, planets, celestial bodies and more /$,'-),',### -' ($),' /,,,$"$')*!!!()$$"%)!)!($%( STELLA is controlled with Meade’s planetarium app, StellaAccess. Available for purchase for both iOS S and Android systems.
    [Show full text]
  • Astrometrically Registered Maps of H2O and Sio Masers Toward VX Sagittarii
    ARTICLE DOI: 10.1038/s41467-018-04767-8 OPEN Astrometrically registered maps of H2O and SiO masers toward VX Sagittarii Dong-Hwan Yoon1,2, Se-Hyung Cho2,3, Youngjoo Yun2, Yoon Kyung Choi2, Richard Dodson4, María Rioja4,5, Jaeheon Kim6, Hiroshi Imai7, Dongjin Kim3, Haneul Yang1,2 & Do-Young Byun2 The supergiant VX Sagittarii is a strong emitter of both H2O and SiO masers. However, previous VLBI observations have been performed separately, which makes it difficult to 1234567890():,; spatially trace the outward transfer of the material consecutively. Here we present the astrometrically registered, simultaneous maps of 22.2 GHz H2O and 43.1/42.8/86.2/129.3 GHz SiO masers toward VX Sagittarii. The H2O masers detected above the dust-forming layers have an asymmetric distribution. The multi-transition SiO masers are nearly circular ring, suggesting spherically symmetric wind within a few stellar radii. These results provide the clear evidence that the asymmetry in the outflow is enhanced after the smaller molecular gas clump transform into the inhomogeneous dust layers. The 129.3 GHz maser arises from the outermost region compared to that of 43.1/42.8/86.2 GHz SiO masers. The ring size of the 129.3 GHz maser is maximized around the optical maximum, suggesting that radiative pumping is dominant. 1 Astronomy Program, Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea. 2 Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Korea. 3 Department of Astronomy, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.
    [Show full text]
  • Monthly Newsletter of the Durban Centre - March 2018
    Page 1 Monthly Newsletter of the Durban Centre - March 2018 Page 2 Table of Contents Chairman’s Chatter …...…………………….……….………..….…… 3 Andrew Gray …………………………………………...………………. 5 The Hyades Star Cluster …...………………………….…….……….. 6 At the Eye Piece …………………………………………….….…….... 9 The Cover Image - Antennae Nebula …….……………………….. 11 Galaxy - Part 2 ….………………………………..………………….... 13 Self-Taught Astronomer …………………………………..………… 21 The Month Ahead …..…………………...….…….……………..…… 24 Minutes of the Previous Meeting …………………………….……. 25 Public Viewing Roster …………………………….……….…..……. 26 Pre-loved Telescope Equipment …………………………...……… 28 ASSA Symposium 2018 ………………………...……….…......…… 29 Member Submissions Disclaimer: The views expressed in ‘nDaba are solely those of the writer and are not necessarily the views of the Durban Centre, nor the Editor. All images and content is the work of the respective copyright owner Page 3 Chairman’s Chatter By Mike Hadlow Dear Members, The third month of the year is upon us and already the viewing conditions have been more favourable over the last few nights. Let’s hope it continues and we have clear skies and good viewing for the next five or six months. Our February meeting was well attended, with our main speaker being Dr Matt Hilton from the Astrophysics and Cosmology Research Unit at UKZN who gave us an excellent presentation on gravity waves. We really have to be thankful to Dr Hilton from ACRU UKZN for giving us his time to give us presentations and hope that we can maintain our relationship with ACRU and that we can draw other speakers from his colleagues and other research students! Thanks must also go to Debbie Abel and Piet Strauss for their monthly presentations on NASA and the sky for the following month, respectively.
    [Show full text]
  • Double and Multiple Star Measurements in the Northern Sky with a 10” Newtonian and a Fast CCD Camera in 2006 Through 2009
    Vol. 6 No. 3 July 1, 2010 Journal of Double Star Observations Page 180 Double and Multiple Star Measurements in the Northern Sky with a 10” Newtonian and a Fast CCD Camera in 2006 through 2009 Rainer Anton Altenholz/Kiel, Germany e-mail: rainer.anton”at”ki.comcity.de Abstract: Using a 10” Newtonian and a fast CCD camera, recordings of double and multiple stars were made at high frame rates with a notebook computer. From superpositions of “lucky images”, measurements of 139 systems were obtained and compared with literature data. B/w and color images of some noteworthy systems are also presented. mented double stars, as will be described in the next Introduction section. Generally, I used a red filter to cope with By using the technique of “lucky imaging”, seeing chromatic aberration of the Barlow lens, as well as to effects can strongly be reduced, and not only the reso- reduce the atmospheric spectrum. For systems with lution of a given telescope can be pushed to its limits, pronounced color contrast, I also made recordings but also the accuracy of position measurements can be with near-IR, green and blue filters in order to pro- better than this by about one order of magnitude. This duce composite images. This setup was the same as I has already been demonstrated in earlier papers in used with telescopes under the southern sky, and as I this journal [1-3]. Standard deviations of separation have described previously [1-3]. Exposure times varied measurements of less than +/- 0.05 msec were rou- between 0.5 msec and 100 msec, depending on the tinely obtained with telescopes of 40 or 50 cm aper- star brightness, and on the seeing.
    [Show full text]
  • Events: General Meeting : Monday, May 4, 2015 at the Temecula Library, 30600 Pauba Rd, Rm
    The monthly newsletter of the Temecula Valley Astronomers May 2015 Events: General Meeting : Monday, May 4, 2015 at the Temecula Library, 30600 Pauba Rd, Rm. B at 7 pm. Tim Deardorff with his What's Up in the night sky and Curtis Croulet presents the “Illustrated history of the building of Palomar Observatory ”. Curtis is a Master Docent at the Observatory. For the latest on Star Parties, check the web page. APOD: Ring Galaxy AM 0644-741 from Hubble Image Credit: Hubble Heritage Team (AURA / STScI), J. Higdon (Cornell) ESA, NASA WHAT’S INSIDE THIS MONTH: General information: Subscription to the TVA is included in the annual $25 membership (regular members) donation ($9 student; $35 Cosmic Comments family). by President Mark Baker Looking Up President: Mark Baker 951-691-0101 by Curtis Croulet ([email protected]) Art's Night Out Vice President & Facebook: Tim Deardorff 951-775-1036 ([email protected]) by Art Cobb Outreach: John Garrett 951-609-3021 Art's Night Out Reloaded (May 2004) ([email protected]) by Art Cobb Treasurer: Curtis Croulet ([email protected]) For Sale or Trade Secretary: Deborah Cheong ([email protected]) Club Librarian: Bob Leffler 951-541-5400 Send newsletter submissions to Mark DiVecchio ([email protected]) ([email protected]) by the 20th of the month for the next month's issue. Star Party Coordinator: Deborah Cheong ([email protected]) Address renewals or other correspondence to: Like us on Facebook Temecula Valley Astronomers PO Box 1292 Murrieta, CA 92564 Mailing List: [email protected]
    [Show full text]
  • Optical Counterparts of ROSAT X-Ray Sources in Two Selected Fields at Low
    Astronomy & Astrophysics manuscript no. sbg˙comsge˙ed c ESO 2018 October 16, 2018 Optical counterparts of ROSAT X-ray sources in two selected fields at low vs. high Galactic latitudes J. Greiner1, G.A. Richter2 1 Max-Planck-Institut f¨ur extraterrestrische Physik, 85740 Garching, Germany 2 Sternwarte Sonneberg, 96515 Sonneberg, Germany Received 14 October 2013 / Accepted 12 August 2014 ABSTRACT Context. The optical identification of large number of X-ray sources such as those from the ROSAT All-Sky Survey is challenging with conventional spectroscopic follow-up observations. Aims. We investigate two ROSAT All-Sky Survey fields of size 10◦× 10◦ each, one at galactic latitude b = 83◦ (26 Com), the other at b = –5◦ (γ Sge), in order to optically identify the majority of sources. Methods. We used optical variability, among other more standard methods, as a means of identifying a large number of ROSAT All- Sky Survey sources. All objects fainter than about 12 mag and brighter than about 17 mag, in or near the error circle of the ROSAT positions, were tested for optical variability on hundreds of archival plates of the Sonneberg field patrol. Results. The present paper contains probable optical identifications of altogether 256 of the 370 ROSAT sources analysed. In partic- ular, we found 126 AGN (some of them may be misclassified CVs), 17 likely clusters of galaxies, 16 eruptive double stars (mostly CVs), 43 chromospherically active stars, 65 stars brighter than about 13 mag, 7 UV Cet stars, 3 semiregular resp. slow irregular variable stars of late spectral type, 2 DA white dwarfs, 1 Am star, 1 supernova remnant and 1 planetary nebula.
    [Show full text]
  • Biennial Report 2006 2007 Published in Spain by the Isaac Newton Group of Telescopes (ING) ISSN 1575–8966 Legal License: TF–1142 /99
    I SAAC N EWTON G ROUP OF T ELESCOPES Biennial Report 2006 2007 Published in Spain by the Isaac Newton Group of Telescopes (ING) ISSN 1575–8966 Legal license: TF–1142 /99 Apartado de correos, 321 E-38700 Santa Cruz de La Palma; Canary Islands; Spain Tel: +34 922 425 400 Fax: +34 922 425 401 URL: http://www.ing.iac.es/ Editor and designer: Javier Méndez ([email protected]) Printing: Gráficas Sabater. Tel: +34 922 623 555 Front cover: The Milky Way from the site of the William Herschel Telescope. Credit: Nik Szymanek. Inset: Photograph of the WHT at sunset. Credit: Nik Szymanek. Other picture credits: Nik Szymanek (WHT, p. 4; INT, p. 4; JKT, p. 4; ING, p. 5); Jens Moser (WHT, back; INT, back); Nik Szymanek (JKT, back). The ING Biennial Report is available online at http://www.ing.iac.es/PR/AR/. ISAAC NEWTON GROUP OF TELESCOPES Biennial Report of the STFC-NWO-IAC ING Board 2006 – 2007 ISAAC NEWTON GROUP William Herschel Telescope Isaac Newton Telescope Jacobus Kapteyn Telescope 4 • ING BIENNIAL R EPORT 2006–2007 OF TELESCOPES The Isaac Newton Group of Telescopes (ING) consists of the 4.2- metre William Herschel Telescope (WHT), the 2.5-metre Isaac Newton Telescope (INT) and the 1.0-metre Jacobus Kapteyn Telescope (JKT). The ING is located 2350 metres above sea level at the Observatorio del Roque de los Muchachos (ORM) on the island of La Palma, Canary Islands, Spain. The WHT is the largest telescope of its kind in Western Europe. The construction, operation, and development of the ING telescopes are the result of a collaboration between the United Kingdom, The Netherlands and Spain.
    [Show full text]
  • A Survey of Active Galaxies at Tev Photon Energies with the HAWC Gamma-Ray Observatory
    Draft version September 22, 2020 Typeset using LATEX default style in AASTeX63 A survey of active galaxies at TeV photon energies with the HAWC gamma-ray observatory A. Albert,1 C. Alvarez,2 J.R. Angeles Camacho,3 J.C. Arteaga-Velazquez,´ 4 K.P. Arunbabu,5 D. Avila Rojas,3 H.A. Ayala Solares,6 V. Baghmanyan,7 E. Belmont-Moreno,3 S.Y. BenZvi,8 C. Brisbois,9 K.S. Caballero-Mora,2 T. Capistran´ ,10 A. Carraminana~ ,10 S. Casanova,7 U. Cotti,4 J. Cotzomi,11 S. Coutino~ de Leon´ ,10 E. De la Fuente,12 B.L. Dingus,1 M.A. DuVernois,13 M. Durocher,1 J.C. D´ıaz-Velez´ ,12 K. Engel,9 C. Espinoza,3 K.L. Fan,9 M. Fernandez´ Alonso,6 H. Fleischhack,14 N. Fraija,15 A. Galvan-G´ amez,´ 15 D. Garc´ıa,3 J.A. Garc´ıa-Gonzalez´ ,3 F. Garfias,15 M.M. Gonzalez´ ,15 J.A. Goodman,9 J.P. Harding,1 S. Hernandez´ ,3 B. Hona,14 D. Huang,14 F. Hueyotl-Zahuantitla,2 P. Huntemeyer,¨ 14 A. Iriarte,15 A. Jardin-Blicq,16, 17, 18 V. Joshi,19 D. Kieda,20 G.J. Kunde,1 A. Lara,5 W.H. Lee,15 H. Leon´ Vargas,3 J.T. Linnemann,21 A.L. Longinotti,10 G. Luis-Raya,22 J. Lundeen,21 K. Malone,1 O. Mart´ınez,11 I. Martinez-Castellanos,9 J. Mart´ınez-Castro,23 J.A. Matthews,24 P. Miranda-Romagnoli,25 J.A. Morales-Soto,4 E. Moreno,11 M.
    [Show full text]