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A new astronomical photo-polarimeter that can measure linear polarization of point sources simultaneously in three spectral bands was designed and built in Indian Institute of Astrophysics. The polarimeter has a Calcite beam-displacement…

Instrumentation and Methods for Astrophysics · Physics 2015-06-30 A. V. Raveendran , G. Srinivasulu , S. Muneer , M. V. Mekkaden , N. Jayavel , M. R. Somashekar , K. Sagayanathan , S. Ramamoorthy , M. J. Rosario , K. Jayakumar

We measured the linear polarization of Sagittarius A* to be 7.2 +/- 0.6 % at 230 GHzusing the BIMA array with a resolution of 3.6 x 0.9 arcsec. This confirms the previously reported detection with the JCMT 14-m antenna. Our high resolution…

Astrophysics · Physics 2008-11-26 Geoffrey C. Bower , Melvyn C. H. Wright , Heino Falcke , Donald C. Backer

Good optical transparency is a fundamental requirement of liquid scintillator (LS) detectors. Characterizing the transparency of a liquid scintillator to its own emitted light is a key parameter to determine the overall sensitivity of a…

Instrumentation and Detectors · Physics 2021-04-28 S. S. Gokhale , R. Rosero , R. Diaz Perez , C. Camilo Reyes , S. Hans , M. Yeh

We explore the use of spectro-polarimetry as a remote sensing tool for asteroids in addition to traditional reflectance measurements. In particular we are interested in possible relationships between the wavelength-dependent variation of…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 S. Bagnulo , A. Cellino , M. Sterzik

We use signal enhancement techniques and a matched filter analysis to search for the K band spectroscopic absorption signature of the close orbiting extrasolar giant planet, HD 189733b. With timeseries observations taken with NIRSPEC at the…

We investigate the reflectivity and optical scattering characteristics at 1064\,nm of an antireflection coated fused silica window of the type being used in the Advanced LIGO gravitational-wave detectors. Reflectivity is measured in the…

We have performed ground-based transmission spectroscopy of the hot Jupiter HAT-P-18b using the ACAM instrument on the William Herschel Telescope (WHT). Differential spectroscopy over an entire night was carried out at a resolution of $R…

Earth and Planetary Astrophysics · Physics 2017-04-25 J. Kirk , P. J. Wheatley , T. Louden , A. P. Doyle , I. Skillen , J. McCormac , P. G. J. Irwin , R. Karjalainen

Spatially resolved polarized millimeter/submillimeter emission has been observed in the disk of HL Tau and two other young stellar objects. It is usually interpreted as coming from magnetically aligned grains, but can also be produced by…

Solar and Stellar Astrophysics · Physics 2018-10-16 Haifeng Yang , Zhi-Yun Li , Leslie Looney , Ian Stephens

We present polarization measurements in the $2-8 \thinspace \mathrm{keV}$ band from blazar 1ES 0229+200, the first extreme high synchrotron peaked source to be observed by the Imaging X-ray Polarimetry Explorer (IXPE). Combining two…

High Energy Astrophysical Phenomena · Physics 2023-10-04 Steven R. Ehlert , Ioannis Liodakis , Riccardo Middei , Alan P. Marscher , Fabrizio Tavecchio , Iván Agudo , Pouya M. Kouch , Elina Lindfors , Kari Nilsson , Ioannis Myserlis , Mark Gurwell , Ramprasad Rao , Francisco Jose Aceituno , Giacomo Bonnoli , Victor Casanova , Beatriz Agiz-Gonzalez , Juan Escudero , Jorge Otero Santos , Alfredo Sota , Emmanouil Angelakis , Alexander Kraus , Garrett K. Keating , Lucio A. Antonelli , Matteo Bachetti , Luca Baldini , Wayne H. Baumgartner , Ronaldo Bellazzini , Stefano Bianchi , Stephen D. Bongiorno , Raffaella Bonino , Alessandro Brez , Niccolò Bucciantini , Fiamma Capitanio , Simone Castellano , Elisabetta Cavazzuti , Chien-Ting Chen , Stefano Ciprini , Enrico Costa , Alessandra De Rosa , Ettore Del Monte , Laura Di Gesu , Niccolò Di Lalla , Alessandro Di Marco , Immacolata Donnarumma , Victor Doroshenko , Michal Dovčiak , Teruaki Enoto , Yuri Evangelista , Sergio Fabiani , Riccardo Ferrazzoli , Javier A. Garcia , Shuichi Gunji , Kiyoshi Hayashida , Jeremy Heyl , Wataru Iwakiri , Svetlana G. Jorstad , Philip Kaaret , Vladimir Karas , Fabian Kislat , Takao Kitaguchi , Jeffery J. Kolodziejczak , Henric Krawczynski , Fabio La Monaca , Luca Latronico , Simone Maldera , Alberto Manfreda , Frédéric Marin , Andrea Marinucci , Herman L. Marshall , Francesco Massaro , Giorgio Matt , Ikuyuki Mitsuishi , Tsunefumi Mizuno , Fabio Muleri , Michela Negro , C. -Y. Ng , Stephen L. O'Dell , Nicola Omodei , Chiara Oppedisano , Alessandro Papitto , George G. Pavlov , Abel L. Peirson , Matteo Perri , Melissa Pesce-Rollins , Pierre-Olivier Petrucci , Maura Pilia , Andrea Possenti , Juri Poutanen , Simonetta Puccetti , Brian D. Ramsey , John Rankin , Ajay Ratheesh , Oliver J. Roberts , Roger W. Romani , Carmelo Sgro , Patrick Slane , Paolo Soffitta , Gloria Spandre , Douglas A. Swartz , Toru Tamagawa , Roberto Taverna , Yuzuru Tawara , Allyn F. Tennant , Nicholas E. Thomas , Francesco Tombesi , Alessio Trois , Sergey S. Tsygankov , Roberto Turolla , Jacco Vink , Martin C. Weisskopf , Kinwah Wu , Fei Xie , Silvia Zane

We present the results of spectropolarimetric observations of 12 Herbig Ae/Be objects. Our data have the largest spectropolarimetric wavelength coverage, 4560 {\AA} to 9480 {\AA}, published to date. A change in linear polarisation across…

Solar and Stellar Astrophysics · Physics 2016-07-27 K. M. Ababakr , R. D. Oudmaijer , J. S. Vink

We present near-simultaneous X-ray and optical polarization measurements in the high synchrotron peaked (HSP) blazar Mrk 421. The X-ray polarimetric observations were carried out using {\it Imaging X-ray Polarimetry Explorer} ({\it IXPE})…

Rayleigh scattering in a hydrogen-dominated exoplanet atmosphere can be detected from ground or space based telescopes, however, stellar activity in the form of spots can mimic Rayleigh scattering in the observed transmission spectrum.…

Earth and Planetary Astrophysics · Physics 2019-02-20 F. Murgas , G. Chen , E. Pallé , L. Nortmann , G. Nowak

As ever-more sensitive experiments are made in the quest for primordial CMB B Modes, the number of potentially significant astrophysical contaminants becomes larger as well. Thermal emission from interplanetary dust, for example, has been…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-07 K. Ganga , M. Maris , M. Remazeilles

We attempt to confirm bright non-LTE emission from the exoplanet HD189733b at 3.25 microns, as recently reported by Swain et al. (2010) based on observations at low spectral resolving power (R ~ 30). Non-LTE emission lines from gas in an…

We use the Spitzer Space Telescope to estimate the dayside thermal emission of the exoplanet TrES-3 integrated in the 3.6, 4.5, 5.8, and 8.0 micron bandpasses of the Infrared Array Camera (IRAC) instrument. We observe two secondary eclipses…

We present the results from the first large (>100 source) 3.5 mm polarimetric survey of radio loud active galactic nuclei (AGN). The I, Q, U, and V Stokes parameter observations were performed with the XPOL polarimeter at the IRAM 30m…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 I. Agudo , C. Thum , H. Wiesemeyer , T. P. Krichbaum

We present H, Ks and L filter polarimetric differential imaging (PDI) data for the transitional disk around HD100546 obtained in 2013, together with an improved re-reduction of previously published 2006 data. We reveal the disk in polarized…

Solar and Stellar Astrophysics · Physics 2015-06-19 Henning Avenhaus , Sascha P. Quanz , Michael R. Meyer , Sean D. Brittain , John S. Carr , Joan R. Najita

We report a sensitive search for meter-wavelength emission at 150 MHz from two prominent transiting extrasolar planets, HD189733b and HD209458b. To distinguish any planetary emission from possible stellar or background contributions, we…

Earth and Planetary Astrophysics · Physics 2015-05-30 A. Lecavelier des Etangs , S. K. Sirothia , Gopal-Krishna , P. Zarka

Multi-band linear polarimetric observations of 125 stars in the region of the cluster NGC 1817 have been carried out intending to study properties of interstellar dust and grains in that direction. The polarization is found to be…

Solar and Stellar Astrophysics · Physics 2020-11-18 Sadhana Singh , Jeewan C. Pandey