Related papers: Measuring Polarization with DASI

A Constraint on Primordial $B$-Modes from the First Flight of the SPIDER Balloon-Borne Telescope

We present the first linear polarization measurements from the 2015 long-duration balloon flight of SPIDER, an experiment designed to map the polarization of the cosmic microwave background (CMB) on degree angular scales. Results from these…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-25 SPIDER Collaboration , P. A. R. Ade , M. Amiri , S. J. Benton , A. S. Bergman , R. Bihary , J. J. Bock , J. R. Bond , J. A. Bonetti , S. A. Bryan , H. C. Chiang , C. R. Contaldi , O. Doré , A. J. Duivenvoorden , H. K. Eriksen , M. Farhang , J. P. Filippini , A. A. Fraisse , K. Freese , M. Galloway , A. E. Gambrel , N. N. Gandilo , K. Ganga , R. Gualtieri , J. E. Gudmundsson , M. Halpern , J. Hartley , M. Hasselfield , G. Hilton , W. Holmes , V. V. Hristov , Z. Huang , K. D. Irwin , W. C. Jones , A. Karakci , C. L. Kuo , Z. D. Kermish , J. S. -Y. Leung , S. Li , D. S. Y. Mak , P. V. Mason , K. Megerian , L. Moncelsi , T. A. Morford , J. M. Nagy , C. B. Netterfield , M. Nolta , R. O'Brient , B. Osherson , I. L. Padilla , B. Racine , A. S. Rahlin , C. Reintsema , J. E. Ruhl , M. C. Runyan , T. M. Ruud , J. A. Shariff , E. C. Shaw , C. Shiu , J. D. Soler , X. Song , A. Trangsrud , C. Tucker , R. S. Tucker , A. D. Turner , J. F. van der List , A. C. Weber , I. K. Wehus , S. Wen , D. V. Wiebe , E. Y. Young

Measuring CMB Polarization with BOOMERANG

BOOMERANG is a balloon-borne telescope designed for long duration (LDB) flights around Antarctica. The second LDB Flight of BOOMERANG took place in January 2003. The primary goal of this flight was to measure the polarization of the CMB.…

Astrophysics · Physics 2015-06-24 T. Montroy , P. A. R. Ade , A. Balbi , J. J. Bock , J. R. Bond , J. Borrill , A. Boscaleri , P. Cabella , C. R. Contaldi , B. P. Crill , P. de Bernardis , G. De Gasperis , A. de Oliveira-Costa , G. De Troia , G. di Stefano , K. Ganga , E. Hivon , V. V. Hristov , A. Iacoangeli , A. H. Jaffe , T. S. Kisner , W. C. Jones , A. E. Lange , S. Masi , P. D. Mauskopf , C. MacTavish , A. Melchiorri , F. Nati , P. Natoli , C. B. Netterfield , E. Pascale , F. Piacentini , D. Pogosyan , G. Polenta , S. Prunet , S. Ricciardi , G. Romeo , J. E. Ruhl , E. Torbet , M. Tegmark , N. Vittorio

Optical Characterization of the BICEP3 CMB Polarimeter at the South Pole

BICEP3 is a small-aperture refracting cosmic microwave background (CMB) telescope designed to make sensitive polarization maps in pursuit of a potential B-mode signal from inflationary gravitational waves. It is the latest in the BICEP/Keck…

Instrumentation and Methods for Astrophysics · Physics 2017-01-18 K. S. Karkare , P. A. R. Ade , Z. Ahmed , K. D. Alexander , M. Amiri , D. Barkats , S. J. Benton , C. A. Bischoff , J. J. Bock , H. Boenish , R. Bowens-Rubin , I. Buder , E. Bullock , V. Buza , J. Connors , J. P. Filippini , S. T. Fliescher , J. A. Grayson , M. Halpern , S. A. Harrison , G. C. Hilton , V. V. Hristov , H. Hui , K. D. Irwin , J. H. Kang , E. Karpel , S. Kefeli , S. A. Kernasovskiy , J. M. Kovac , C. L. Kuo , E. M. Leitch , M. Lueker , K. G. Megerian , V. Monticue , T. Namikawa , C. B. Netterfield , H. T. Nguyen , R. O'Brient , R. W. Ogburn , C. Pryke , C. D. Reintsema , S. Richter , M. T. St. Germaine , R. Schwarz , C. D. Sheehy , Z. K. Staniszewski , B. Steinbach , G. P. Teply , K. L. Thompson , J. E. Tolan , C. Tucker , A. D. Turner , A. G. Vieregg , A. Wandui , A. Weber , J. Willmert , C. L. Wong , W. L. K. Wu , K. W. Yoon

An improved upper limit to the CMB circular polarization at large angular scales

Circular polarization of the Cosmic Microwave Background (CMB) offers the possibility of detecting rotations of the universe and magnetic fields in the primeval universe or in distant clusters of galaxies. We used the Milano Polarimeter…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-05 R. Mainini , D. Minelli , M. Gervasi , G. Boella , G. Sironi , A. Bau' , S. Banfi , A. Passerini , A. De Lucia , F. Cavaliere

A Measurement of the Cosmic Microwave Background Damping Tail from the 2500-square-degree SPT-SZ survey

We present a measurement of the cosmic microwave background (CMB) temperature power spectrum using data from the recently completed South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) survey. This measurement is made from observations of 2540…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 K. T. Story , C. L. Reichardt , Z. Hou , R. Keisler , K. A. Aird , B. A. Benson , L. E. Bleem , J. E. Carlstrom , C. L. Chang , H-M. Cho , T. M. Crawford , A. T. Crites , T. de Haan , M. A. Dobbs , J. Dudley , B. Follin , E. M. George , N. W. Halverson , G. P. Holder , W. L. Holzapfel , S. Hoover , J. D. Hrubes , M. Joy , L. Knox , A. T. Lee , E. M. Leitch , M. Lueker , D. Luong-Van , J. J. McMahon , J. Mehl , S. S. Meyer , M. Millea , J. J. Mohr , T. E. Montroy , S. Padin , T. Plagge , C. Pryke , J. E. Ruhl , J. T. Sayre , K. K. Schaffer , L. Shaw , E. Shirokoff , H. G. Spieler , Z. Staniszewski , A. A. Stark , A. van Engelen , K. Vanderlinde , J. D. Vieira , R. Williamson , O. Zahn

The new generation CMB B-mode polarization experiment: POLARBEAR

We describe the Cosmic Microwave Background (CMB) polarization experiment called Polarbear. This experiment will use the dedicated Huan Tran Telescope equipped with a powerful 1,200-bolometer array receiver to map the CMB polarization with…

Instrumentation and Methods for Astrophysics · Physics 2011-04-25 The Polarbear Collaboration , J. Errard , P. A. R. Ade , A. Anthony , K. Arnold , F. Aubin , D. Boettger , J. Borrill , C. Cantalupo , M. A. Dobbs , D. Flanigan , A. Ghribi , N. Halverson , M. Hazumi , W. L. Holzapfel , J. Howard , P. Hyland , A. Jaffe , B. Keating , T. Kisner , Z. Kermish , A. T. Lee , E. Linder , M. Lungu , T. Matsumura , N. Miller , X. Meng , M. Myers , H. Nishino , R. O'Brient , D. O'Dea , C. Reichardt , I. Schanning , A. Shimizu , C. Shimmin , M. Shimon , H. Spieler , B. Steinbach , R. Stompor , A. Suzuki , T. Tomaru , H. T. Tran , C. Tucker , E. Quealy , P. L. Richards , O. Zahn

CMB polarization TE power spectrum estimation with non-circular beam

Precise measurements of the Cosmic Microwave Background (CMB) anisotropy 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…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-20 Fidy A. Ramamonjisoa , Subharthi Ray , Sanjit Mitra , Tarun Souradeep

A Measurement of the Largest-Scale CMB E-mode Polarization with CLASS

We present measurements of large-scale cosmic microwave background (CMB) E-mode polarization from the Cosmology Large Angular Scale Surveyor (CLASS) 90 GHz data. Using 115 det-yr of observations collected through 2024 with a variable-delay…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-09 Yunyang Li , Joseph Eimer , John Appel , Charles Bennett , Michael Brewer , Sarah Marie Bruno , Ricardo Bustos , Carol Chan , David Chuss , Joseph Cleary , Sumit Dahal , Rahul Datta , Jullianna Denes Couto , Kevin Denis , Rolando Dunner , Thomas Essinger-Hileman , Kathleen Harrington , Kyle Helson , Johannes Hubmayr , Jeffrey Iuliano , John Karakla , Tobias Marriage , Nathan Miller , Carolina Morales Perez , Lucas Parker , Matthew Petroff , Rodrigo Reeves , Karwan Rostem , Caleigh Ryan , Rui Shi , Koji Shukawa , Deniz Valle , Duncan Watts , J. Weiland , Edward Wollack , Zhilei Xu , Lingzhen Zeng

The Signature of Patchy Reionization in the Polarization Anisotropy of the CMB

The inhomogeneous ionization state of the universe when the first sources of ionizing radiation appeared should lead to anisotropies in the polarization of the cosmic microwave background. We use cosmological simulations of the process by…

Astrophysics · Physics 2008-11-26 Olivier Doré , Gil Holder , Marcelo Alvarez , Ilian T. Iliev , Garrelt Mellema , Ue-Li Pen , Paul R. Shapiro

Measurements of B-mode Polarization of the Cosmic Microwave Background from 500 Square Degrees of SPTpol Data

We report a B-mode power spectrum measurement from the cosmic microwave background (CMB) polarization anisotropy observations made using the SPTpol instrument on the South Pole Telescope. This work uses 500 deg$^2$ of SPTpol data, a…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 J. T. Sayre , C. L. Reichardt , J. W. Henning , P. A. R. Ade , A. J. Anderson , J. E. Austermann , J. S. Avva , J. A. Beall , A. N. Bender , B. A. Benson , F. Bianchini , L. E. Bleem , J. E. Carlstrom , C. L. Chang , H. C. Chiang , R. Citron , C. Corbett Moran , T. M. Crawford , A. T. Crites , T. de Haan , M. A. Dobbs , W. Everett , J. Gallicchio , E. M. George , A. Gilbert , N. Gupta , N. W. Halverson , N. Harrington , G. C. Hilton , G. P. Holder , W. L. Holzapfel , J. D. Hrubes , N. Huang , J. Hubmayr , K. D. Irwin , L. Knox , A. T. Lee , D. Li , A. Lowitz , J. J. McMahon , S. S. Meyer , L. M. Mocanu , J. Montgomery , A. Nadolski , T. Natoli , J. P. Nibarger , G. Noble , V. Novosad , S. Padin , S. Patil , C. Pryke , J. E. Ruhl , B. R. Saliwanchik , K. K. Schaffer , C. Sievers , G. Smecher , A. A. Stark , C. Tucker , K. Vanderlinde , T. Veach , J. D. Vieira , G. Wang , N. Whitehorn , W. L. K. Wu , V. Yefremenko

MSAM1-94: Repeated Measurement of Medium-Scale Anisotropy in the Cosmic Microwave Background Radiation

The second flight of the Medium Scale Anisotropy Measurement (MSAM1-94) observed the same field as the first flight (MSAM1-92) to confirm our earlier measurement of cosmic microwave background radiation (CMBR) anisotropy. This instrument…

Astrophysics · Physics 2009-10-28 E. S. Cheng , D. A. Cottingham , D. J. Fixsen , C. A. Inman , M. S. Kowitt , S. S. Meyer , L. A. Page , J. L. Puchalla , J. E. Ruhl , R. F. Silverberg

A Measurement of the Cosmic Microwave Background B-Mode Polarization Power Spectrum at Sub-Degree Scales with POLARBEAR

We report a measurement of the B-mode polarization power spectrum in the cosmic microwave background (CMB) using the POLARBEAR experiment in Chile. The faint B-mode polarization signature carries information about the Universe's entire…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-17 The POLARBEAR Collaboration , P. A. R. Ade , Y. Akiba , A. E. Anthony , K. Arnold , M. Atlas , D. Barron , D. Boettger , J. Borrill , S. Chapman , Y. Chinone , M. Dobbs , T. Elleflot , J. Errard , G. Fabbian , C. Feng , D. Flanigan , A. Gilbert , W. Grainger , N. W. Halverson , M. Hasegawa , K. Hattori , M. Hazumi , W. L. Holzapfel , Y. Hori , J. Howard , P. Hyland , Y. Inoue , G. C. Jaehnig , A. H. Jaffe , B. Keating , Z. Kermish , R. Keskitalo , T. Kisner , M. Le Jeune , A. T. Lee , E. M. Leitch , E. Linder , M. Lungu , F. Matsuda , T. Matsumura , X. Meng , N. J. Miller , H. Morii , S. Moyerman , M. J. Myers , M. Navaroli , H. Nishino , H. Paar , J. Peloton , D. Poletti , E. Quealy , G. Rebeiz , C. L. Reichardt , P. L. Richards , C. Ross , I. Schanning , D. E. Schenck , B. D. Sherwin , A. Shimizu , C. Shimmin , M. Shimon , P. Siritanasak , G. Smecher , H. Spieler , N. Stebor , B. Steinbach , R. Stompor , A. Suzuki , S. Takakura , T. Tomaru , B. Wilson , A. Yadav , O. Zahn

CMB observations with the Cosmic Background Imager (CBI) Interferometer

We review the recently published results from the CBI's first season of observations. Angular power spectra of the CMB were obtained from deep integrations of 3 single fields covering a total of 3 deg^2 and 3 shallower surveys of…

Astrophysics · Physics 2007-05-23 C. R. Contaldi , J. R. Bond , D. Pogosyan , B. S. Mason , S. T. Myers , T. J. Pearson , U. L. Pen , S. Prunet , A. C. Readhead , M. I. Ruetalo , J. L. Sievers , J. W. Wadsley , P. J. Zhang

Calibration Measurements of the BICEP3 and BICEP Array CMB Polarimeters from 2017 to 2024

The BICEP3 and BICEP Array polarimeters are small-aperture refracting telescopes located at the South Pole designed to measure primordial gravitational wave signatures in the Cosmic Microwave Background (CMB) polarization, predicted by…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-26 Christos Giannakopoulos , Clara Vergès , P. A. R. Ade , Zeeshan Ahmed , Mandana Amiri , Denis Barkats , Ritoban Basu Thakur , Colin A. Bischoff , Dominic Beck , James J. Bock , Hans Boenish , Victor Buza , James R. Cheshire , Jake Connors , James Cornelison , Michael Crumrine , Ari Jozef Cukierman , Edward Denison , Marion Dierickx , Lionel Duband , Miranda Eiben , Brodi D. Elwood , Sofia Fatigoni , Jeff P. Filippini , Antonio Fortes , Min Gao , Neil Goeckner-Wald , David C. Goldfinger , James A. Grayson , Paul K. Grimes , Grantland Hall , George Halal , Mark Halpern , Emma Hand , Sam A. Harrison , Shawn Henderson , Johannes Hubmayr , Howard Hui , Kent D. Irwin , Jae Hwan Kang , Kirit S. Karkare , Sinan Kefeli , J. M. Kovac , Chao-Lin Kuo , King Lau , Margaret Lautzenhiser , Amber Lennox , Tongtian Liu , Koko G. Megerian , Oliver Miller , Lorenzo Minutolo , Lorenzo Moncelsi , Yuka Nakato , H. T. Nguyen , Roger O'brient , Anika Patel , Matthew A. Petroff , Anna R. Polish , Nathan Precup , Thomas Prouve , Clement Pryke , Carl D. Reintsema , Thibault Romand , Maria Salatino , Alessandro Schillaci , Benjamin Schmitt , Baibhav Singari , Ahmed Soliman , Tyler St Germaine , Aaron Steiger , Bryan Steinbach , Rashmi Sudiwala , Keith L. Thompson , Calvin Tsai , Carole Tucker , Anthony D. Turner , Abigail G. Vieregg , Albert Wandui , Alexis C. Weber , Justin Willmert , Wai Ling K. Wu , Hung-I Yang , Cyndia Yu , Lingzhen Zeng , Cheng Zhang , Silvia Zhang

Simulation of Cosmic Microwave Background Polarization Fields for AMiBA Experiment

We have made a topological study of cosmic microwave background (CMB) polarization maps by simulating the AMiBA experiment results. A $\Lambda$CDM CMB sky is adopted to make mock interferometric observations designed for the AMiBA…

Astrophysics · Physics 2017-01-18 Chan-Gyung Park , Changbom Park

Probing CMB Polarization Gaussianity with the Statistics of Unpolarized Points: Non-Gaussianity of Planck Data and Prospects for Future B-Mode Measurements

We present a Gaussianity test of the cosmic microwave background (CMB) polarization by analyzing the statistics of unpolarized points in the sky, classified into three distinct types: saddles, comets, and beaks. This classification of…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-01 K. O. Parfenov , D. I. Novikov , A. O. Mihalchenko

Planck 2015 results. XVI. Isotropy and statistics of the CMB

We test the statistical isotropy and Gaussianity of the cosmic microwave background (CMB) anisotropies using observations made by the Planck satellite. Our results are based mainly on the full Planck mission for temperature, but also…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-21 Planck Collaboration , P. A. R. Ade , N. Aghanim , Y. Akrami , P. K. Aluri , M. Arnaud , M. Ashdown , J. Aumont , C. Baccigalupi , A. J. Banday , R. B. Barreiro , N. Bartolo , S. Basak , E. Battaner , K. Benabed , A. Benoît , A. Benoit-Lévy , J. -P. Bernard , M. Bersanelli , P. Bielewicz , J. J. Bock , A. Bonaldi , L. Bonavera , J. R. Bond , J. Borrill , F. R. Bouchet , F. Boulanger , M. Bucher , C. Burigana , R. C. Butler , E. Calabrese , J. -F. Cardoso , B. Casaponsa , A. Catalano , A. Challinor , A. Chamballu , H. C. Chiang , P. R. Christensen , S. Church , D. L. Clements , S. Colombi , L. P. L. Colombo , C. Combet , D. Contreras , F. Couchot , A. Coulais , B. P. Crill , M. Cruz , A. Curto , F. Cuttaia , L. Danese , R. D. Davies , R. J. Davis , P. de Bernardis , A. de Rosa , G. de Zotti , J. Delabrouille , F. -X. Désert , J. M. Diego , H. Dole , S. Donzelli , O. Doré , M. Douspis , A. Ducout , X. Dupac , G. Efstathiou , F. Elsner , T. A. Enßlin , H. K. Eriksen , Y. Fantaye , J. Fergusson , R. Fernandez-Cobos , F. Finelli , O. Forni , M. Frailis , A. A. Fraisse , E. Franceschi , A. Frejsel , A. Frolov , S. Galeotta , S. Galli , K. Ganga , C. Gauthier , T. Ghosh , M. Giard , Y. Giraud-Héraud , E. Gjerløw , J. González-Nuevo , K. M. Górski , S. Gratton , A. Gregorio , A. Gruppuso , J. E. Gudmundsson , F. K. Hansen , D. Hanson , D. L. Harrison , S. Henrot-Versillé , C. Hernández-Monteagudo , D. Herranz , S. R. Hildebrandt , E. Hivon , M. Hobson , W. A. Holmes , A. Hornstrup , W. Hovest , Z. Huang , K. M. Huffenberger , G. Hurier , A. H. Jaffe , T. R. Jaffe , W. C. Jones , M. Juvela , E. Keihänen , R. Keskitalo , J. Kim , T. S. Kisner , J. Knoche , M. Kunz , H. Kurki-Suonio , G. Lagache , A. Lähteenmäki , J. -M. Lamarre , A. Lasenby , M. Lattanzi , C. R. Lawrence , R. Leonardi , J. Lesgourgues , F. Levrier , M. Liguori , P. B. Lilje , M. Linden-Vørnle , H. Liu , M. López-Caniego , P. M. Lubin , J. F. Macías-Pérez , G. Maggio , D. Maino , N. Mandolesi , A. Mangilli , D. Marinucci , M. Maris , P. G. Martin , E. Martínez-González , S. Masi , S. Matarrese , P. McGehee , P. R. Meinhold , A. Melchiorri , L. Mendes , A. Mennella , M. Migliaccio , K. Mikkelsen , S. Mitra , M. -A. Miville-Deschênes , D. Molinari , A. Moneti , L. Montier , G. Morgante , D. Mortlock , A. Moss , D. Munshi , J. A. Murphy , P. Naselsky , F. Nati , P. Natoli , C. B. Netterfield , H. U. Nørgaard-Nielsen , F. Noviello , D. Novikov , I. Novikov , C. A. Oxborrow , F. Paci , L. Pagano , F. Pajot , N. Pant , D. Paoletti , F. Pasian , G. Patanchon , T. J. Pearson , O. Perdereau , L. Perotto , F. Perrotta , V. Pettorino , F. Piacentini , M. Piat , E. Pierpaoli , D. Pietrobon , S. Plaszczynski , E. Pointecouteau , G. Polenta , L. Popa , G. W. Pratt , G. Prézeau , S. Prunet , J. -L. Puget , J. P. Rachen , R. Rebolo , M. Reinecke , M. Remazeilles , C. Renault , A. Renzi , I. Ristorcelli , G. Rocha , C. Rosset , M. Rossetti , A. Rotti , G. Roudier , J. A. Rubiño-Martín , B. Rusholme , M. Sandri , D. Santos , M. Savelainen , G. Savini , D. Scott , M. D. Seiffert , E. P. S. Shellard , T. Souradeep , L. D. Spencer , V. Stolyarov , R. Stompor , R. Sudiwala , R. Sunyaev , D. Sutton , A. -S. Suur-Uski , J. -F. Sygnet , J. A. Tauber , L. Terenzi , L. Toffolatti , M. Tomasi , M. Tristram , T. Trombetti , M. Tucci , J. Tuovinen , L. Valenziano , J. Valiviita , B. Van Tent , P. Vielva , F. Villa , L. A. Wade , B. D. Wandelt , I. K. Wehus , D. Yvon , A. Zacchei , J. P. Zibin , A. Zonca

The POLARBEAR Experiment

We present the design and characterization of the POLARBEAR experiment. POLARBEAR will measure the polarization of the cosmic microwave background (CMB) on angular scales ranging from the experiment's 3.5 arcminute beam size to several…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 Z. Kermish , P. Ade , A. Anthony , K. Arnold , K. Arnold , D. Barron , D. Boettger , J. Borrill , S. Chapman , Y. Chinone , M. A. Dobbs , J. Errard , G. Fabbian , D. Flanigan , G. Fuller , A. Ghribi , W. Grainger , N. Halverson , M. Hasegawa , K. Hattori , M. Hazumi , W. L. Holzapfel , J. Howard , P. Hyland , A. Jaffe , B. Keating , T. Kisner , A. T. Lee , M. Le Jeune , E. Linder , M. Lungu , F. Matsuda , T. Matsumura , X. Meng , N. J. Miller , H. Morii , S. Moyerman , M. J. Myers , H. Nishino , H. Paar , E. Quealy , C. L. Reichardt , P. L. Richards , C. Ross , A. Shimizu , M. Shimon , C. Shimmin , M. Sholl , P. Siritanasak , H. Spieler , N. Stebor , B. Steinbach , R. Stompor , A. Suzuki , T. Tomaru , C. Tucker , O. Zahn

The CMB polarization: status and prospects

The study of cosmic microwave background (CMB) polarization is still in a pioneering stage, but promises to bring a huge advancement in cosmology in the near future, just as high-accuracy observations of the anisotropies in the total…

Astrophysics · Physics 2007-05-23 Amedeo Balbi , Paolo Natoli , Nicola Vittorio

Testing physical models for dipolar asymmetry with CMB polarization

The cosmic microwave background (CMB) temperature anisotropies exhibit a large-scale dipolar power asymmetry. To determine whether this is due to a real, physical modulation or is simply a large statistical fluctuation requires the…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-07 D. Contreras , J. P. Zibin , D. Scott , A. J. Banday , K. M. Górski