DOCSLIB.ORG

Transmission Spectroscopy of the Hot Jupiter Tres-3 B: Disproof of an Overly Large Rayleigh-Like Feature

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Transmission Spectroscopy of the Hot Jupiter Tres-3 B: Disproof of an Overly Large Rayleigh-Like Feature Transmission spectroscopy of the hot Jupiter TrES-3 b: Disproof of an overly large Rayleigh-like feature Mackebrandt, F., Mallonn, M., Ohlert, J. M., Granzer, T., Lalitha, S., Munoz, A. G., Gibson, N. P., Lee, J. W., Sozzetti, A., Turner, J. D., Vanko, M., & Strassmeier, K. G. (2017). Transmission spectroscopy of the hot Jupiter TrES-3 b: Disproof of an overly large Rayleigh-like feature. Astronomy & Astrophysics, 608, 1-13. [A26]. https://doi.org/10.1051/0004-6361/201730512 Published in: Astronomy & Astrophysics Document Version: Publisher's PDF, also known as Version of record Queen's University Belfast - Research Portal: Link to publication record in Queen's University Belfast Research Portal Publisher rights Copyright ESO 2017. This work is made available online in accordance with the publisher’s policies. Please refer to any applicable terms of use of the publisher. General rights Copyright for the publications made accessible via the Queen's University Belfast Research Portal is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The Research Portal is Queen's institutional repository that provides access to Queen's research output. Every effort has been made to ensure that content in the Research Portal does not infringe any person's rights, or applicable UK laws. If you discover content in the Research Portal that you believe breaches copyright or violates any law, please contact [email protected]. Download date:27. Sep. 2021 A&A 608, A26 (2017) DOI: 10.1051/0004-6361/201730512 Astronomy c ESO 2017 & Astrophysics Transmission spectroscopy of the hot Jupiter TrES-3 b: Disproof of an overly large Rayleigh-like feature?,?? F. Mackebrandt1; 2, M. Mallonn1, J. M. Ohlert3; 4, T. Granzer1, S. Lalitha5, A. García Muñoz6, N. P.Gibson7, J. W. Lee8; 9, A. Sozzetti10, J. D. Turner11, M. Vankoˇ 12, and K. G. Strassmeier1 1 Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany e-mail: [email protected] 2 Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany 3 Michael Adrian Observatorium, Astronomie Stiftung Trebur, 65468 Trebur, Germany 4 University of Applied Sciences, Technische Hochschule Mittelhessen, 61169 Friedberg, Germany 5 Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India 6 Zentrum für Astronomie und Astrophysik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany 7 Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN, UK 8 Korea Astronomy and Space Science Institute, 34055 Daejeon, Korea 9 Astronomy and Space Science Major, Korea University of Science and Technology, 34113 Daejeon, Korea 10 INAF–Osservatorio Astrofisico di Torino, via Osservatorio 20, 10025 Pino Torinese, Italy 11 Department of Astronomy, University of Virginia, Charlottesville, VA 22904, USA 12 Astronomical Institute, Slovak Academy of Sciences, 059 60 Tatranská Lomnica, Slovakia Received 27 January 2017 / Accepted 2 September 2017 ABSTRACT Context. Transit events of extrasolar planets offer the opportunity to study the composition of their atmospheres. Previous work on transmission spectroscopy of the close-in gas giant (TrES)-3 b revealed an increase in absorption towards blue wavelengths of very large amplitude in terms of atmospheric pressure scale heights, too large to be explained by Rayleigh-scattering in the planetary atmosphere. Aims. We present a follow-up study of the optical transmission spectrum of the hot Jupiter TrES-3 b to investigate the strong increase in opacity towards short wavelengths found by a previous study. Furthermore, we aim to estimate the effect of stellar spots on the transmission spectrum. Methods. This work uses previously published long slit spectroscopy transit data of the Gran Telescopio Canarias (GTC) and pub- lished broad band observations as well as new observations in different bands from the near-UV to the near-IR, for a homogeneous transit light curve analysis. Additionally, a long-term photometric monitoring of the TrES-3 host star was performed. Results. Our newly analysed GTC spectroscopic transit observations show a slope of much lower amplitude than previous studies. We conclude from our results the previously reported increasing signal towards short wavelengths is not intrinsic to the TrES-3 system. Furthermore, the broad band spectrum favours a flat spectrum. Long-term photometric monitoring rules out a significant modification of the transmission spectrum by unocculted star spots. Key words. planets and satellites: atmospheres – stars: individual: TrES-3 – methods: data analysis – techniques: spectroscopic – techniques: photometric 1. Introduction is absorbed until an optical depth of about unity. Wavelength- dependent variations in the atmospheres optical depth cause vari- Transiting exoplanets present a unique opportunity to probe the ations in that transit depth. This yields information about atoms, upper regions of their atmospheres. During transit, the stellar molecules, and condensates in the outer (optically thin) region light passes through the annulus of the planet’s atmosphere and of the planetary atmosphere. ? Based on (1) data obtained with the STELLA robotic telescopes in The magnitude of the wavelength dependence of the tran- Tenerife, an AIP facility jointly operated by AIP and IAC, (2) observa- sit depth can be approximated by the area of the planetary at- tions collected at the German-Spanish Astronomical Center, Calar Alto, mosphere compared to the area of the star. Therefore, the ob- jointly operated by the Max-Planck-Institut für Astronomie Heidelberg servability of the transmission signal is maximised for planets and the Instituto de Astrofísica de Andalucía (CSIC) and (3) observa- with a large planet-to-star radius ratio and a large atmospheric tions made with the Italian Telescopio Nazionale Galileo (TNG) oper- pressure scale height. The majority of atmospheric character- ated on the island of La Palma by the Fundación Galileo Galilei of the isations have been accomplished for hot Jupiter exoplanets INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del (Sing et al. 2016). However, observations of transmission spec- Roque de los Muchachos of the Instituto de Astrofisica de Canarias. ?? Newly observed photometric data from Sects. 2.2 and 2.3 and tables tra of Neptune-sized planets (e.g. Fraine et al. 2014) and super- of the lightcurves are only available at the CDS via anonymous ftp to Earths (e.g. Kreidberg et al. 2014) have also been published. cdsarc.u-strasbg.fr (130.79.128.5) or via The vertical extent of the atmospheric annulus probed by http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/608/A26 transmission spectroscopy at optical wavelengths is about five Article published by EDP Sciences A26, page 1 of 13 A&A 608, A26 (2017) to ten scale heights for gas giants (Seager et al. 2009; Burrows in units of scale height among all hot Jupiter transmission spec- 2014; Madhusudhan et al. 2014). This signal size is predicted tra and so far cannot be theoretically explained (P16). However, for atomic and molecular absorption in cloud/haze-free atmo- P16 analysed only a single transit measurement. sphere models as well as for Rayleigh-scattering in hazy at- In this work we target the reliability and repeatability of mospheres (Fortney et al. 2010; Miller-Ricci & Fortney 2010; this outstanding transmission signal. Therefore, we reanalyse Wakeford & Sing 2015). The vast majority of detected trans- the Gran Telescopio Canarias (GTC) transit observation used by mission signals is in agreement with this amplitude or lower P16 and homogeneously analyse 36 published and 15 newly ob- (e.g. Sing et al. 2016; Sedaghati et al. 2016; Kreidberg et al. served broad band transit observations in nine band passes from 2015; Fraine et al. 2014; Nikolov et al. 2016; Gibson et al. the near-UV until the near-IR to build a broad band spectropho- 2017). Stronger amplitudes measured in the UV can be un- tometry transmission spectrum for comparison. Our aim is to derstood as Lyα absorption in the planetary escaping exo- verify whether the signal is intrinsic to the TrES-3 system or sphere (Ehrenreich et al. 2015; Vidal-Madjar et al. 2003). How- rather caused by artefacts in the data or aspects of the data anal- ever, measured transmission signals of more than ten scale ysis, rather than a detailed atmospheric characterisation. heights amplitude at optical wavelengths have been proposed We performed a photometric long-term monitoring of the (Southworth et al. 2015; Mancini et al. 2014; Turner et al. 2016; host star TrES-3 to search for rotational modulation potentially Parviainen et al. 2016). The physical interpretation of these re- caused by star spots (Strassmeier 2009). Unocculted star spots sults is challenging, because according to our current under- on the visible hemisphere of the star influence the transit pho- standing these signals cannot entirely be caused by the plan- tometry and therefore the derived transit parameters (Pont et al. etary atmosphere. Does stellar activity influence the measure- 2013). This effect is wavelength dependent and can potentially ments (Oshagh et al. 2013), or does contamination from a nearby introduce a slope in the transmission spectrum similar to a spec- star play a role (Southworth & Evans 2016)? Are the values of tral scattering signature produced by Rayleigh or Mie scatter- the planetary scale height underestimated, which would point to ing by condensate particles (Oshagh et al. 2014). The monitoring a severely wrong estimation of planetary parameters, or are the program allows us to estimate an upper limit of the spot filling uncertainties in the transmission spectroscopy measurements un- factor and the modification of the measured transit depth. derestimated? Could there be missing physics in the modelling This paper is structured as follows: Sects. 2 and 3 describe of exoplanet transmission spectra? the observations and the data reduction.
Load more

Recommended publications
  • PRECISE PHOTOMETRIC TRANSIT FOLLOW-UP OBSERVATIONS of FIVE CLOSE-IN EXOPLANETS : UPDATE on THEIR PHYSICAL PROPERTIES Aritra Chakrabarty†1, 2 and Sujan Sengupta‡1
    Draft version May 28, 2019 Typeset using LATEX default style in AASTeX62 PRECISE PHOTOMETRIC TRANSIT FOLLOW-UP OBSERVATIONS OF FIVE CLOSE-IN EXOPLANETS : UPDATE ON THEIR PHYSICAL PROPERTIES Aritra Chakrabartyy1, 2 and Sujan Senguptaz1 1Indian Institute of Astrophysics, Koramangala 2nd Block, Bangalore 560034, India 2University of Calcutta, Salt Lake City, JD-2, Kolkata 750098, India (Accepted for publication in the Astronomical Journal) ABSTRACT We report the results of the high precision photometric follow-up observations of five transiting hot jupiters - WASP-33b, WASP-50b, WASP-12b, HATS-18b and HAT-P-36b. The observations are made from the 2m Himalayan Chandra Telescope at Indian Astronomical Observatory, Hanle and the 1.3m J. C. Bhattacharyya Telescope at Vainu Bappu Observatory, Kavalur. This exercise is a part of the capability testing of the two telescopes and their back-end instruments. Leveraging the large aperture of both the telescopes used, the images taken during several nights were used to produce the transit light curves with high photometric S/N (> 200) by performing differential photometry. In order to reduce the fluctuations in the transit light curves due to various sources such as stellar activity, varying sky transparency etc. we preprocessed them using wavelet denoising and applied Gaussian process correlated noise modeling technique while modeling the transit light curves. To demonstrate the efficiency of the wavelet denoising process we have also included the results without the denoising process. A state-of-the-art algorithm used for modeling the transit light curves provided the physical parameters of the planets with more precise values than reported earlier.
    [Show full text]
  • Indian Institute of Astrophysics
    Indian Institute of Astrophysics The Indian Institute of Astrophysics (IIA), an autonomous research institute funded by the Department of Science & Technology, is devoted to research in Astronomy & Astrophysics, and the Related Physics and Instrumentation. IIA has a rich history of over two centuries and has to its credit some important discoveries such as those of the Evershed effect, atmosphere on Jupiter's satellite Ganymede, the rings around Uranus and the asteroid Ramanujan. Research Programmes Research fields in Astronomy & Astrophysics at IIA range from the studies of the nearby sun and solar system objects to the distant galaxies, quasars and gamma-ray burst sources. Sun and the Solar System - Solar activity - sunspots, prominences; Solar Chromosphere and Corona; Comets; Solar Terrestrial relationships Stellar Physics - Formation and Evolution of Stars; Comet Machholz Planetary Nebulae; Stellar Atmospheres; Star observed from VBO Clusters; Stellar Variability; Novae; Supernovae; Brown Dwarfs, Pulsars Solar Corona Extragalactic Astronomy - Star formation in galaxies; Activity in Galaxies; Groups and Clusters of Galaxies; Gamma-ray burst events Theoretical Astrophysics and Related Physics - Magnetohydrodynamic and Radiative Processes in Astrophysical Objects; Structure of Neutron Stars; Blackhole Physics; Structure and Dynamics of Galaxies and Star Clusters; General Theory of Relativity; Cosmology; Astroparticle Physics; Atomic and Molecular Physics NGC 925 observed with the 2m HCT Instrumentation - UV Imaging Telescope for the Indian Astronomy Satellite (ASTROSAT); back-end instruments for the various observing facilities. Facilities The Institute's research activities are supported by excellent facilities at its headquarters in Bangalore and its field stations at Kodaikanal, Kavalur, Gauribidanur, Hosakote and Hanle. The Solar Observatory: located at Kodaikanal consists of a Tower Tunnel Telescope, Spectroheliographs and Ionosondes.
    [Show full text]
  • Indian Institute of Astrophysics Bangalore 560034
    Indian Institute of Astrophysics Bangalore 560034 The Indian Institute of Astrophysics (IIA) traces its origin to relativity, cosmology, astroparticle physics, atomic and a small private observatory set up during 1786 at Madras molecular physics. (Chennai), which led to the establishment of the Solar Observatory in 1899 at Kodaikanal. In 1971, the Facilities: Kodaikanal Observatory was made into an autonomous institution under the Department of Science & Technology, Kodaikanal Observatory: This Observatory has been the Government of India. With a rich history of over 200 years, principal center of activity in observational solar physics, IIA is a premier institute in the country devoted to basic for over a century. At present, the main facility is the solar research, instrumentation and training in astronomy, tunnel telescope fitted with a spectrograph, which is in astrophysics and related physical sciences. regular use since 1962; a spectro-polarimeter has also been added. This observatory has a unique collection of the Sun’s photographic images archived over the last hundred years. These images are now being digitized to study the finer details of the Sun, Sun-weather pattern etc. Daily observations of the solar photosphere and chromosphere are being obtained as a part of the synoptic study. It was in this Observatory, John Evershed discovered the radial motion in sunspots, now known as the Evershed effect, in 1909. The Indian Institute of Astrophysics, Bangalore. Research Programmes: Sun and the Solar System - Solar activity, sunspots, prominences, solar chromosphere, comets, asteroids, eclipse observations, radio observations of the solar corona. Stellar Physics - Formation and evolution of stars, chemical abundance of elements, planetary nebulae, planetary rings, The solar tunnel telescope at the Kodaikanal observatory.
    [Show full text]
  • Arxiv:1505.04244V1 [Astro-Ph.IM] 16 May 2015 .Srinivasulu G
    Bull. Astr. Soc. India (2014) 42, 1–19 A new three-band, two beam astronomical photo-polarimeter 1 2 1 3 G. Srinivasulu ∗, A. V. Raveendran , S. Muneer †, M. V. Mekkaden , N. Jayavel4, M. R. Somashekar1, K. Sagayanathan1, S. Ramamoorthy1, 5 6 M. J. Rosario and K. Jayakumar ‡ 1Indian Institute of Astrophysics, Bangalore 560034, India 2399, "Shravanam", 2nd Block, 9th Phase, J P Nagar, Bangalore 560108, India 3No 82, 17E Main, 6th Block, Koramangala, Bangalore 560095, India 4No 22, Bandappa lane, New Byappanahalli, Bangalore 560038, India 5210, 4th Main, Lakshmi Nagar Extn, Porur, Chennai 600116, India 624, Postal Nagar, Ampuram, Vellore-632009, India Received 2014 July 23; revised ; accepted Abstract. We designed and built a new astronomical photo-polarimeter that can meas- ure linear polarization simultaneously in three spectral bands. It has a Calcite beam- displacement prism as the analyzer. The ordinary and extra-ordinary emerging beams in each spectral bands are quasi-simultaneously detected by the same photomultiplier by using a high speed rotating chopper. A rotating superachromatic Pancharatnam halfwave plate is used to modulate the light incident on the analyzer. The spectral bands are isolated using appropriate dichroic and glass filters. We show that the reduction of 50% in the efficiency of the polarimeter because of the fact that the intensities of the two beams are measured alternately is partly com- pensated by the reduced time to be spent on the observation of the sky background. The use of a beam-displacement prism as the analyzer completely removes the polar- ization of backgroundskylight, which is a major source of error during moonlit nights, especially, in the case of faint stars.
    [Show full text]
  • Multi-Band Observations of Gamma Ray Bursts
    J. Astrophys. Astr. (2002) 23, 123–127 Multi-band Observations of Gamma Ray Bursts S. G. Bhargavi Indian Institute of Astrophysics, Bangalore 560 034, India email: [email protected] Abstract. This talk focuses on the various aspects we learnt from multi- band observations of GRBs both, before and during the afterglow era. A statistical analysis to estimate the probable redshifts of host galaxies using the luminosity function of GRBs compatible with both the afterglow redshift data as well as the overall population of GRBs is discussed. We then address the question whether the observed fields of GRBs with precise localizations from third Inter-Planetary Network (IPN3) contain suitable candidates for their host galaxies. Key words. Gamma rays: bursts—CCD: observations—Methods: statistical. 1. Studies before the afterglow era In 1994–95 we undertook a program to carry out an optical survey of a few GRB fields chosen from the IPN3 catalog (Hurley 1995, private communication; Laros et al. 1998; Hurley et al. 2000). Deep CCD imaging of these fields was carried out at the 2.34 m and 1.02 m telescopes of Vainu Bappu Observatory (VBO), Kavalur until 1998. It was an attempt to identify the transient/quiescent counterparts of GRBs on the basis of photometric studies. For details on observations and photometric data analysis see Bhargavi (2001). In similar investigations the observers either looked for peculiar objects (Vrba et al. 1995) or an over-abundance of certain class of objects (Larson 1997) in their deep imaging surveys of IPN GRBs. None of our efforts led to an identification of a GRB counterpart.
    [Show full text]
  • 1 Introduction 2 Vainu Bappu Observatory, Kavalur, Indian Institute
    GROUND-BASED OPTICAL ASTRONOMY IN INDIA M.Parthasarathy, Indian Institute of Astrophysics, Bangalore - 560034 India Abstract There is considerable progress in the ground based optical astronomy in India during the last 25 years. During the period 1965 to 1995 four one meter class telescopes and one 2.3m telescope have corne into operation. The number of users of these facilities has increased considerably. The existing optical telescpes in India are heavily over-subscribed and are not large enough for observing fainter stars and faint and distant galaxies . There is an urgent need to set up at good sites in India 4m class new technology telescopes and a few 1m and 2m class telescopes equipped with upto date auxiliary instruments. 1 Introduction During the last 30 years, a number of telescopes have become available in India for astronomical observations over different regions of the electromagnetic spectrum ranging from Gamma-rays, X-rays, optical, infrared and radio wavelength regions. In this paper the existing facilities for ground-based optical astronomy in India are described. The research work in optical astronomy in India and future plans to set up new 2m to 4m class telescopes are also described. There are five major existing optical telescopes in India: (i) a 1m Carl-Zeiss telescope at Naini Tal, (ii) a 1.2m Baker reflector at Rangapur near Hyderbad, (iii) a 1m Carl-Zeiss telescope and a 2.3m Vainu Bappu Telescope (VBT) at Kava1ur, (iv) a 1.2m infrared telescope at Gurusikhar near Mount Abu. There are also three main solar observatories in India at Kodaikanal, Udaipur and N aini Tal.
    [Show full text]
  • Productivity of Indian Telescopes: Impact Analysis Through Scientometric Methods by Meera B.M
    Productivity of Indian Telescopes: Impact Analysis through Scientometric methods By Meera B.M. & Manjunath M. Raman Research Institute, Bangalore, India Abstract: This paper aims to study the productivity of modern Indian telescopes installed after India attained Data representation and analysis independence from colonial rule. However, there is one telescope which was built during colonial rule and still Collective productivity data from all telescopes is represented below functional. Productivity measure is the number of papers published from 14 telescopes under study. Astronomical data A comprehensive table (1) represents data from 14 telescopes of India which are under study. observed through these telescopes gets transformed into research papers. Such papers further get used by their peers and Telescope Name Telescope type Year Year of Total No. Total Average H-Index Total No. of get cited. This is the actual impact of the telescopes in terms of scholarship. This aspect will be analyzed in this paper established publicat of papers No. of citations Number Authors Total Productivity of Total Refereed using scientometric indicators. ion of published citations per of with 14 Indian Telescopes Metrics first received paper authors Foreign Number of papers 1,643 1,144 Indian Astronomical studies dates back to 1500 B C. Astronomy was article affiliation Introduction: (%) Total reads 326,351 310,594 considered as “Auxiliary discipline” with the study of Veda (Knowledge base originated in Kodaikanal Solar Observatory, Solar Observatory 1899 1904 361 689 1.9 15 395 165 (41%) Kodaikanal Average reads 198.6 271.5 ancient India comprising of large body of text). Original application of astronomy was Ooty Radio Telescope, Ooty Radio Telescope 1970 1971 114 792 6.9 16 132 30 (23%) Number of citations 13,599 13,083 religious and later this had Greek influence during 4th century.
    [Show full text]
  • Early Time Optical Spectroscopy of Supernova SN 1998S
    A&A 367, 506–512 (2001) Astronomy DOI: 10.1051/0004-6361:20000427 & c ESO 2001 Astrophysics Early time optical spectroscopy of supernova SN 1998S G. C. Anupama, T. Sivarani, and G. Pandey Indian Institute of Astrophysics, II Block Koramangala, Bangalore 560 034, India Received 26 June 2000 / Accepted 4 December 2000 Abstract. We present medium-resolution optical spectra of the type II supernova SN 1998S obtained during the pre-maximum, maximum and early decline phases. The early decline spectra show complex Balmer line profiles: a narrow P-Cygni emission feature superimposed on a broad emission. The narrow emission has a redshift similar to that of the host galaxy, indicating its origin from a pre-supernova circumstellar material. The Hα luminosity of the broad component implies a shell mass of ∼0.1 M for the supernova ejecta, while the luminosity of the −4 −1 narrow component implies a mass loss rate of 10 M yr for the precursor. The photospheric temperature of the supernova shell decreased from a value of 18 400 2900 K on day 17 to a value of 7500 1200 K on day 44. The observations indicate SN 1998S belongs to type IIn supernovae where the supernova ejecta dynamically interact with a pre-supernova circumstellar material. Key words. supernovae: general – supernovae: individual (SN 1998S) 1. Introduction or broad (FWHM ∼ 5000–10000 km s−1) base. The cen- troid of the base is blue-shifted relative to the narrow por- The supernova SN 1998S was discovered in the SCII.2 tion of the profile. The continuum is bluer than normal galaxy NGC 3877 on 1998 March 2.68 by Z.
    [Show full text]
  • LIEMFO-Anupama
    Follow-up of GW-EM in Optical and NIR G.C. Anupama Indian Institute of Astrophysics EM counterparts of GW Sources Electromagnetic Observations • Nature of GW source – BH events, BNS, Collapse of massive stars, WD collapse (?) • Pinning down the position of the sources • Identify the host galaxy and environment • Suite of telescopes and instruments spread across the globe • (γ − rays, X-rays, UV), Optical, NIR, (mm, radio) - Photometry, spectroscopy, polarization • Wide field optical and NIR transient search observations • Deep observations – several transients – important to have rapid spectroscopic observations for source classification • Long term monitoring Observing Facilities in India • Longitudinal Advantage Existing Facilities Vainu Bappu Observatory ■ Established in late 1960s ■ Location: 12d 34m N; 78d 50m E; Altitude: 720m ■ 175kms South-East of Bangalore 2.3 metre Vainu Bappu Telescope F/3.25 primary mirror; F/13 Cassegrain focus • Cassegrain OMR low resolution spectrograph (R=500-2000) • VBT Fiber-fed Echelle Spectrograph (Prime focus fiber feed; R=30000, 70000) 1 metre Zeiss telescope F/13 Cassegrain focus • Low resolution spectrograph (UAGS) • PhotoPolarimeter 1.3 metre Telescope F/8 Cassegrain focus; 30 arcminute corrected field. • 2K X 4K imager and 1K X 1K rapid imager • FoV: 5.5 X 11 arcmin Indian Astronomical Observatory Mt. Saraswati (Digpa-ratsa Ri), Hanle ■ Location: 32d46m46s N; 78d57m51s E ■ High altitude Gamma Ray Array Telescope (HAGAR) ■ Altitude: 4500m (15000ft) ■ 22m Imaging Cherenkov Telescope (MACE) – under
    [Show full text]
  • Development of Image Motion Compensation System for 1.3 M Telescope at Vainu Bappu Observatory
    RAA 2020 Vol. 20 No. 1, 12(14pp) doi: 10.1088/1674–4527/20/1/12 R c 2020 National Astronomical Observatories, CAS and IOP Publishing Ltd. esearch in Astronomy and http://www.raa-journal.org http://iopscience.iop.org/raa Astrophysics Development of image motion compensation system for 1.3 m telescope at Vainu Bappu Observatory Sreekanth Reddy Vallapureddy⋆, Ravinder Kumar Banyal, Sridharan Rengaswamy, P Umesh Kamath and Aishwarya Selvaraj Indian Institute of Astrophysics, Bangalore 560034, India; [email protected] Received 2019 July 16; accepted 2019 August 28 Abstract We developed a tip-tilt system to compensate the turbulence induced image motion for the 1.3m telescope at Vainu Bappu Observatory, at Kavalur. The instrument is designed to operate at the visible wavelength band (480 700nm) with a field of view of 1′ 1′. The tilt corrected images have demonstrated − × up to 57% improvement in image resolution and a corresponding peak intensity increase by a factor of ≈ 2.8. A closed-loop correction bandwidth of 26Hz has been achieved with on-sky tests and the root ≈ ≈ mean square motion of the star image has been reduced by a factor of 14. These results are consistent ∼ with theoretical and numerical predictions of wave-front aberrations caused by atmospheric turbulence and image quality improvement expected from a real-time control system. In this paper, we present details of the instrument design, laboratory calibration studies and quantify its performance on the telescope. Key words: adaptive optics — atmospheric effects — high angular resolution 1 INTRODUCTION times also called the angle of arrival fluctuations.
    [Show full text]
  • Observing Facilities of IIA
    Observing Facilities of IIA IIA Bangalore The Indian Institute of Astrophysics (IIA), with its headquarters in Bangalore (Karnataka state), India, is a premier national institute of India for the study of and research into topics pertaining to astronomy, astrophysics and related subjects. The Institute has a network of laboratories and observatories located in various places in India, including Kodaikanal (the Kodaikanal Solar Observatory), Kavalur (the Vainu Bappu Observatory), Gauribidanur, Hanle (the Indian Astronomical Observatory) and Hosakote. Indian Astronomical Observatory Vainu Bappu Observatory, Kavalur The Indian Astronomical Observatory, the 2.34m VBT high-altitude station of IIA is situated at an M.K. V. Bappu, the founder altitude of 4500 metres above mean sea Director of IIA had set up an level to the north of Western Himalayas. A observatory for the night time 2-m optical infrared telescope (HCT) is observations at Kavalur located in installed at the observatory. This telescope javadi hills of Tamilnadu, to access is remotely operated from CREST, the celestial objects both in the north Hosakote, using a dedicated satellite links and southern hemispheres. With a 15 and being used by Indian astronomers inch refractor and a 30 inch reflector since 2001. Telescope is equipped with instruments called HFOSC & NIRCam. operating from late 60s, a 1M Carl Observatory also host 0.5m robotic Zeiss reflector was installed in 1973. telescope for monitoring transient objects Development of an indigenous as well as a Gamma ray telescope2m HAGAR HCT 2.34M reflector was initiated by Dr to study AGN’s pulsars, and host of Bappu. The telescope was completed astrophysical sources.
    [Show full text]
  • Once in a Blue Moon: Detection of 'Bluing' During Debris Transits in The
    Once in a blue moon: detection of ‘bluing' during debris transits in the white dwarf WD 1145+017 Item Type Article Authors Hallakoun, N.; Xu (), S.; Maoz, D.; Marsh, T. R.; Ivanov, V. D.; Dhillon, V. S.; Bours, M. C. P.; Parsons, S. G.; Kerry, P.; Sharma, S.; Su, K.; Rengaswamy, S.; Pravec, P.; Kušnirák, P.; Kučáková, H.; Armstrong, J. D.; Arnold, C.; Gerard, N.; Vanzi, L. Citation Once in a blue moon: detection of ‘bluing' during debris transits in the white dwarf WD 1145+017 2017, 469 (3):3213 Monthly Notices of the Royal Astronomical Society DOI 10.1093/mnras/stx924 Publisher OXFORD UNIV PRESS Journal Monthly Notices of the Royal Astronomical Society Rights © 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Download date 06/10/2021 05:37:47 Item License http://rightsstatements.org/vocab/InC/1.0/ Version Final published version Link to Item http://hdl.handle.net/10150/625505 MNRAS 469, 3213–3224 (2017) doi:10.1093/mnras/stx924 Advance Access publication 2017 April 17 Once in a blue moon: detection of ‘bluing’ during debris transits in the white dwarf WD 1145+017 N. Hallakoun,1,2‹ S. Xu (),2 D. Maoz,1 T. R. Marsh,3 V. D. Ivanov,4,2 V. S. Dhillon,5,6 M. C. P. Bours,7 S. G. Parsons,5 P. Kerry,5 S. Sharma,8 K. Su,9 S. Rengaswamy,10 P. Pravec,11 P. Kusnirˇ ak,´ 11 H. Kucˇakov´ a,´ 12 J. D. Armstrong,13,14 C. Arnold,13 N. Gerard13 and L.
    [Show full text]