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Browsing by Author "Sivarani, T"

Browsing by Author "Sivarani, T"

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  • Decoding the compositions of four bright r-process-enhanced stars 
    Saraf, Pallavi; Prieto, Carlos Allende; Sivarani, T; Bandyopadhyay, A; Beers, Timothy C.; Susmitha, A (Oxford University Press on behalf of Royal Astronomical Society, 2023-10)
    There has been a concerted effort in recent years to identify the astrophysical sites of the r-process that can operate early in the galaxy. The discovery of many r-process-enhanced (RPE) stars (especially by the R-process ...
  • Design and development of WFOS, the Wide-Field Optical Spectrograph for the Thirty Meter Telescope 
    Steidel, Charles; Peng, Eric; Fucik, Jason; Nash, Reston; Kaye, Stephen; Jacoby, George; Delabre, Bernard; Ramya, S; Divakar, Devika; Varshney, Hari Mohan; Sivarani, T; Uraguchi, Fumihiro; Ozaki, Shinobu; Ji, Hangxin; Tao, L V; Chiu, Kent; Zhu, Qinfeng; Andersen, David; Miles, John; Lasi, Davide (SPIE-The International Society for Optical Engineering, 2022-08)
    We present the current design of WFOS, a wide-field UV/optical (0.31-1.0 µm) imaging spectrograph planned for first-light on the TMT International Observatory 30 m telescope. WFOS is optimized for high sensitivity across ...
  • Design of an IR imaging channel for the Keck Observatory SCALES instrument 
    Banyal, R. K; Hasan, Armirul; Kupke, Reni; Varshney, Hari Mohan; Prakaesh, Ajin; Sivarani, T; Skemer, Andy J; MacDonald, Nick; Sallum, Steph; Deich, Will; Fitzgerald, Michael P; Govinda, K. V; Ratliff, Chris; Ramya, S; Stelter, Deno; Surya, Arun; Wang, Eric (SPIE-The International Society for Optical Engineering, 2022-08)
    A next-generation instrument named, Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy (SCALES), is being planned for the W. M. Keck Observatory. SCALES will have an integral field spectrograph (IFS) and a ...
  • Design of SCALES: a 2-5 micron coronagraphic integral field spectrograph for Keck Observatory 
    Skemer, Andrew J; Stelter, R. Deno; Sallum, Stephanie; MacDonald, Nicholas; Kupke, Renate; Ratliff, Christopher; Banyal, R. K; Hasan, Amirul; Varshney, Hari Mohan; Surya, Arun; Prakaesh, Ajin; Sivarani, T; Ramya, S; Govinda, K. V; Fitzgerald, Michael P; Wang, Eric; Kassis, Marc; Absil, Olivier; Alvarez, Carlos; Batalha, Natasha; Boucher, Marc-Andre; Bourgenot, Cyril; Brandt, Timothy; Briesemeister, Zackery; Kleer, Katherine de; Pater, Imke de; Deich, William; Divakar, Devika; Filion, Guillaume; Gauvin, Etienne; Gonzales, Michael; Greene, Thomas; Hinz, Philip; Jensen-Clem, Rebecca; Johnson, Christopher; Kain, Isabel; Kruglikov, Gabriel; Lach, Mackenzie; Landry, Jean-Thomas; Li, Jialin; Liu, Michael C; Lyke, James; Magnon, Kenneth; Marin, Eduardo; Martin, Emily; Martinez, Raquel; Mawet, Dimitri; Miles, Brittany; Sandford, Dale; Sheehan, Patrick; Sohn, Ji Man; Stone, Jordan (SPIE-The International Society for Optical Engineering, 2022-08)
    We present the design of SCALES (Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy) a new 2-5 micron coronagraphic integral field spectrograph under construction for Keck Observatory. SCALES enables ...
  • Designing custom medium resolution observing modes to trace planet accretion with SCALES 
    Martinez, Raquel A; Sallum, Steph; Banyal, R. K; Batalha, Natalie; Batalha, Natasha; Blake, Geoff; Brandt, Tim; Briesemeister, Zack; Kleer, Katherine de; Pater, Imke de; Desai, Aditi; Eisner, Josh; Fong, Wen-fai; Greene, Tom; Honda, Mitsuhiko; Kain, Isabel; Kilpatrick, Charlie; Kupke, Renate; Lach, Mackenzie; Liu, Mike; Macintosh, Bruce; Mawet, Dimitri; Miles, Brittany; Morley, Caroline; Powell, Diana; Sheehan, Patrick; Skemer, Andrew J; Spilker, Justin; Stelter, Deno; Stone, Jordan; Surya, Arun; Sivarani, T; Wagner, Kevin; Zhou, Yifan (SPIE-The International Society for Optical Engineering, 2023-10)
    The Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy (SCALES) is an under-construction thermal infrared high-contrast integral field spectrograph that will be located at the W. M. Keck Observatory. SCALES ...
  • Detecting Outliers in SDSS using Convolutional Neural Network 
    Sharma, K; Kembhavi, Ajit; Kembhavi, Aniruddha; Sivarani, T; Abraham, S. (Societe Royale des Sciences de Liege, 2019-10)
    We propose an automated algorithm based on Convolutional Neural Network (CNN) for the detection of peculiar objects in large databases using their spectral observations. A convolutional neural network is a class of ...
  • Development of a stabilized fabry-perot based wavelength calibrator for precision doppler spectroscopy 
    Tanya, Das; Banyal, R. K; Kathiravan, S; Sivarani, T; Ravindra, B (SPIE-The International Society for Optical Engineering, 2018-07-06)
    Precision Doppler spectroscopy serves as an important tool for Radial Velocity (RV) observations of stars. High precision spectroscopy is bound by two major challenges, first being the instrument instability which is ...
  • The development of HISPEC for Keck and MODHIS for TMT: science cases and predicted sensitivities 
    Konopacky, Quinn M; Baker, Ashley D; Mawet, Dimitri; Fitzgerald, Michael P; Jovanovic, Nemanja; Beichman, Charles; Ruane, Garreth; Bertz, Rob; Terada, Hiroshi; Dekany, Richard; Lingvay, Larry; Kassis, Marc; Anderson, David; Tamura, Motohide; Benneke, Bjorn; Beatty, Thomas; Do, Tuan; Nishiyama, Shogo; Plavchan, Peter; Wang, Jason; Wang, Ji; Burgasser, Adam; Ruffio, Jean-Baptiste; Zhang, Huihao; Brown, Aaron; Fucik, Jason; Gibbs, Aidan; Gibson, Rose; Halverson, Sam; Johnson, Christopher; Karkar, Sonia; Kotani, Takayuki; Kress, Evan; Leifer, Stephanie; Magnone, Kenneth; Maire, Jerome; Pahuja, Rishi; Porter, Michael; Roberts, Mitsuko; Sappey, Ben; Thorne, Jim; Wang, Eric; Artigau, Etienne; Blake, Geoffrey A; Canalizo, Gabriela; Chen, Guo; Doppmann, Greg; Doyon, Rene; Dressing, Courtney; Fang, Min; Greene, Thomas; Herczeg, Greg; Hillenbrand, Lynne; Howard, Andrew; Kane, Stephen; Kataria, Tiffany; Kempton, Eliza; Knutson, Heather; Lafrenière, David; Liu, Chao; Metchev, Stanimir; Millar-Blanchaer, Max; Narita, Norio; Pandey, G; Rajaguru, S. P; Robertson, Paul; Salyk, Colette; Sato, Bun’ei; Schlawin, Evertt; Sengupta, S; Sivarani, T; Skidmore, Warren; Vasisht, Gautam; Yasui, Chikako; Zhang, Hui (SPIE-The International Society for Optical Engineering, 2023-10)
    HISPEC is a new, high-resolution near-infrared spectrograph being designed for the W.M. Keck II telescope. By offering single-shot, R 100,000 spectroscopy between 0.98 – 2.5 µm, HISPEC will enable spectroscopy of transiting ...
  • Discovery of a Low-mass Companion to a Metal-rich F Star with the MARVELS Pilot Project 
    Fleming, S. W; Ge, J; Mahadevan, S; Lee, B; Eastman, J. D; Siverd, R. J; Gaudi, B. S; Niedzielski, A; Sivarani, T; Stassun, K. G; Wolszczan, A; Barnes, R; Gary, B; Nguyen, Duy Cuong; Morehead, R. C; Wan, X; Zhao, B; Liu, J; Guo, P; Kane, S. R; van Eyken, J. C; Lee, N. M. D; Crepp, J. R; Shelden, A. C; Laws, C; Wisniewski, J. P; Schneider, D. P; Pepper, J; Snedden, S. A; Pan, K; Bizyaev, D; Brewington, H; Malanushenko, O; Malanushenko, V; Oravetz, D; Simmons, A; Watters, S (IOP Publishing, 2010-08-01)
    We report the discovery of a low-mass companion orbiting the metal-rich, main sequence F star TYC 2949-00557-1 during the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS) pilot project. The host star ...
  • Early time optical spectroscopy of supernova SN 1998S 
    Anupama, G. C; Sivarani, T; Pandey, G (EDP Sciences, 2001-02)
    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 ...
  • The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III 
    Aihara, H; Allende Prieto, C; An, D; Anderson, S. F; Aubourg, E; Balbinot, E; Beers, T. C; Berlind, A. A; Bickerton, S. J; Bizyaev, D; Blanton, M. R; Gillespie, B. A; Pan, K; Gilmore, G; González Hernández, J. I; Bochanski, J. J; Gott, J. R; Gould, A; Grebel, E. K; Mullally, F; Gunn, J. E; Phleps, S; Hamilton, J; Harding, P; Carr, M. A; Harris, D. W; Hawley, S. L; Hearty, F. R; Nichol, R. C; Ho, S; Hogg, D. W; Holtzman, J. A; Davenport, J. R. A; Honscheid, K; Muna, D; Inada, N; Pandey, P; Ivans, I. I; Jiang, L; Johnson, J. A; Jordan, C; O'Connell, R. W; Jordan, W. P; Pichon, C; Kazin, E. A; Kirkby, D; Klaene, M. A; Knapp, G. R; Paris, I; Munn, J. A; Kneib, J; Kochanek, C. S; Koesterke, L; Kollmeier, J. A; Pieri, M. M; Ogando, R. L. C; Kron, R. G; Lampeitl, H; Lang, D; Le Goff, J; Bolton, A. S; Lee, Y. S; Lin, Y; Murayama, H; Long, D. C; Chen, Y; Loomis, C. P; Lucatello, S; Olmstead, M. D; Lundgren, B; Lupton, R. H; Ma, Z; Percival, W. J; MacDonald, N; Mahadevan, S; Maia, M. A. G; Prada, F; Makler, M; Myers, A. D; Malanushenko, E; Malanushenko, V; Oravetz, D. J; Mandelbaum, R; Maraston, C; Petitjean, P; Margala, D; Masters, K. L; Price-Whelan, A. M; McBride, C. K; McGehee, P. M; McGreer, I. D; Ménard; Naugle, T; Fausti Neto, A; Padmanabhan, N; Palanque-Delabrouille, N; Pfaffenberger, R; Pforr, J; Raddick, M. J; Bovy, J; Ramos, B. H. F; Esposito, M; Reyle, C; Rich, J; Miralda-Escudé, J; Richards, G. T; Rix, H; Robin, A. C; Chiappini, C; Rocha-Pinto, H. J; Rockosi, C. M; Roe, N. A; Cuong Nguyen, D; Rollinde, E; Brandt, W. N; Ross, A. J; Dawson, K; Ross, N. P; Rossetto, B. M; Sánchez, A. G; Sayres, C; Comparat, J; Schlegel, D. J; Evans, M. L; Schlesinger, K. J; Schmidt, S. J; Schneider, D. P; Sheldon, E; Dhital, S; Brinkmann, J; Shu, Y; Simmerer, J; Simmons, A. E; Sivarani, T; Fan, X; Connolly, N; Snedden, S. A; Sobeck, J. S; Steinmetz, M; Strauss, M. A; Ealet, A; Szalay, A. S; Tanaka, M; Brown, P. J; Thakar, A. R; Morrison, H. L; Thomas, D; Tinker, J. L; Cortes, M; Tofflemire, B. M; Tojeiro, R; Tremonti, C. A; Ebelke, G. L; Vandenberg, J; Vargas Magaña, M; Verde, L; Femenía Castellá, B; Vogt, N. P; Brownstein, J. R; Wake, D. A; Wang, J; Croft, R. A. C; Weaver, B. A; Weinberg, D. H; Edmondson, E. M; White, M; White, S. D. M; Font-Ribera, A; Yanny, B; Yasuda, N; Yeche, C; Zehavi, I; Busca, N. G; Campbell, H; Cuesta, A. J; da Costa, L. N; Eisenstein, D. J; Escoffier, S; Frinchaboy, P. M; Ge, J (IOP Publishing, 2011-04)
    The Sloan Digital Sky Survey (SDSS) started a new phase in 2008 August, with new instrumentation and new surveys focused on Galactic structure and chemical evolution, measurements of the baryon oscillation feature in the ...
  • The eleventh and twelfth data releases of the sloan digital sky survey: final data from SDSS-III 
    Alam, S; Albareti, F. D; Prieto, C. A; Anders, F; Anderson, S. F; Anderton, T; Andrews, B. H; Armengaud, E; Aubourg, E; Bailey, S; Basu, S; Bautista, J. E; Beaton, R. L; Beers, T. C; Bender, C. F; Berlind, A. A; Beutler, F; Bhardwaj, V; Bird, J. C; Bizyaev, D; Blake, C. H; Blanton, M. R; Blomqvist, M; Bochanski, J. J; Bolton, A. S; Bovy, J; Bradley, A. S; Brandt, W. N; Brauer, D. E; Brinkmann, J; Brown, P. J; Brownstein, J. R; Burden, A; Burtin, E; Busca, N. G; Cai, Z; Capozzi, D; Rosell, A. C; Carr, M. A; Carrera, R; Chambers, K. C; Chaplin, W. J; Chen, Y-C; Chiappini, C; Chojnowski, S. D; Chuang, C-H; Clerc, N; Comparat, J; Covey, K; Croft, R. A. C; Cuesta, A. J; Cunha, K; da Costa, L. N; Da Rio, N; Davenport, J. R. A; Dawson, K. S; De Lee, N; Delubac, T; Deshpande, R; Dhital, S; Dutra-Ferreira, L; Dwelly, T; Ealet, A; Ebelke, G. L; Edmondson, E. M; Eisenstein, D. J; and 237 coauthors; Sivarani, T (IOP Publishing, 2015-07-20)
    The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new ...
  • Erratum: "The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III" (2011, ApJS, 193, 29) 
    Aihara, H and 178 coauthors; Sivarani, T (IOP Publishing, 2011-08)
  • The [Fe/H], [C/Fe], and [α/Fe] Distributions of the Boötes I Dwarf Spheroidal Galaxy 
    Lai, D. K; Lee, Y. S; Bolte, M; Lucatello, S; Beers, T. C; Johnson, J. A; Sivarani, T; Rockosi, C. M (IOP Publishing, 2011-09-01)
    We present the results of a low-resolution spectral abundance study of 25 stars in the Boötes I dwarf spheroidal (dSph) galaxy. The data were obtained with the low resolution imaging spectrometer instrument at Keck Observatory ...
  • Field blue straggler stars: discovery of white dwarf companions to blue metal-poor stars using UVIT/AstroSat 
    Panthi, Anju; Subramaniam, A; Vaidya, Kaushar; Jadhav, Vikrant V; Sharmila Rani; Sivarani, T; Pandey, Sindhu (Oxford University Press on behalf of Royal Astronomical Society, 2023-10)
    Blue metal-poor (BMP) stars are the main-sequence stars that appear bluer and more luminous than normal turn-off stars of metal-poor globular clusters. They are believed to be either field blue straggler stars (FBSS) formed ...
  • First stars. XIII. Two extremely metal-poor RR Lyrae stars 
    Hansen, C. J; Nordström, B; Bonifacio, P; Spite, M; Andersen, J; Beers, T. C; Cayrel, R; Spite, F; Molaro, P; Barbuy, B; Depagne, E; François, P; Hill, V; Plez, B; Sivarani, T (EDP Sciences, 2011-03)
    Context. The chemical composition of extremely metal-poor stars (EMP stars; [Fe/H] < ~ −3) is a unique tracer of early nucleosynthesis in the Galaxy. As such stars are rare, we wish to find classes of luminous stars ...
  • Flexure compensation simulation tool for TMT-WFOS spectrograph 
    Surya, Arun; Radovan, Matthew; Sivarani, T; Sriram, S; Devika, Divakar; Fucik, Jason (SPIE--The International Society for Optical Engineering, 2018-07)
    The Wide Field Optical Spectrograph (WFOS) is one of the first-light instruments of Thirty Meter Telescope. It is a medium resolution, multi object, wide field optical spectrograph. Since 2005 the conceptual design of the ...
  • Galactic Chemical Evolution of Exoplanet Hosting Stars: Are High-mass Planetary Systems Young? 
    Swastik, C; Banyal, R. K; Narang, Mayank; Manoj, P; Sivarani, T; Rajaguru, S. P; Athira Unni; Banerjee, Bihan (American Astronomical Society, 2022-08-01)
    The imprints of stellar nucleosynthesis and chemical evolution of the galaxy can be seen in different stellar populations, with older generation stars showing higher α-element abundances and the later generations ...
  • Globular Cluster UVIT Legacy Survey (GlobULeS) – I. FUV–optical colour–magnitude diagrams for eight globular clusters 
    Sahu, Snehalata; Subramaniam, A; Singh, Gaurav; Yadav, Ramakant; Valcarce, Aldo R; Choudhury, Samyaday; Sharmila Rani; Deepthi, S. Prabhu; Chung, Chul; Cote, Patrick; Leigh, Nathan; Geller, Aaron M; Chatterjee, Sourav; Kameswara Rao, N; Bandyopadhyay, Avrajit; Shara, Michael; Dalessandro, Emanuele; Pandey, G; Postma, Joesph E; Hutchings, John; Simunovic, Mirko; Stetson, Peter B; Sivarani, T; Puzia, Thomas; Sohn, Young-Jong (Oxford University Press on behalf of the Royal Astronomical Society, 2022-07)
    We present the first results of eight globular clusters (GCs) from the AstroSat/UVIT Legacy Survey programme GlobULeS based on the observations carried out in two far-ultraviolet (FUV) filters (F148W and F169M). The ...
  • Globular Cluster UVIT Legacy Survey (GlobULeS). III. Omega Centauri in Far-ultraviolet 
    Deepthi, S. Prabhu; Subramaniam, A; Sahu, Snehalata; Chung, Chul; Leigh, Nathan W. C; Dalessandro, Emanuele; Chatterjee, Sourav; Kameswara Rao, N; Shara, Michael; Cote, Patrick; Choudhury, Samyaday; Pandey, G; Valcarce, Aldo A. R; Singh, G; Postma, Joesph E; Sharmila Rani; Bandyopadhyay, Avrajit; Geller, Aaron M; Hutchings, John; Puzia, Thomas; Simunovic, Mirko; Sohn, Young-Jong; Sivarani, T; Yadav, Ramakant Singh (American Astronomical Society, 2022-11-10)
    We present the first comprehensive study of the most massive globular cluster, Omega Centauri, in the farultraviolet (FUV), extending from the center to ∼28% of the tidal radius using the Ultraviolet Imaging Telescope on ...

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