IIA Institutional Repository: Recent submissions

  • Calibration of subsystems of visible emission line coronagraph 
    Pruthvi, Suryadevara (Indian Institute of Astrophysics, 2019-07)
    Aditya-L1, India’s first mission with multiple science payloads is designed to study the solar dynamics. Aditya-L1 includes multiple payloads, the significant one being the Visible Emission Line Coronagraph (VELC). ...
  • Study and design of a soft X-ray imager and spectrometer for observation of non-flaring Sun 
    Choudhary, Sarthak (Indian Institute of Astrophysics, 2019-06)
    The outer most layer of the Sun, also called Corona, reaches temperatures as high as a few million Kelvin much hotter than underlying photosphere and chromosphere. This phenomenon is popularly known as coronal heating. ...
  • Calibration of spectral channels for VELC onboard ADITYA-L1 and preparing data pipeline 
    Madhu, Vishnu (Indian Institute of Astrophysics, 2019-06)
    ADITYA-L1 will be India’s first space mission dedicated to solar studies. The Visible Emission Line Coronagraph (VELC) is one of the prime payloads onboard ADITYA L1. VELC will perform simultaneous imaging, spectroscopy ...
  • Single shot solar spectroscopic design aspects 
    Mathur, Harsh (Indian Institute of Astrophysics, 2019-06)
    High time-cadence Spectro-Polarimetry allows the feasibility of studying magnetic field evolution coupled with the plasma flows. Such a high cadence solar spectro-polarimetry if developed will allow one to study magnetic ...
  • Development of 6U spectrograph payload for NUV studies 
    Bharat Chandra, P (Indian Institute of Astrophysics, 2019-06)
    One of the most exciting parts of the astrophysical spectrum is the near ultraviolet (NUV: 1800 – 3000Å), where there are a number of important atomic and molecular lines. The hot gas in the halo emits in NUV and also ...
  • Development of radio antenna array and receiver system for observations of Pulsars at Low Radio Frequencies 
    Bane Kshitij, Suhas Trupti (Indian Institute of Astrophysics, 2019-06)
    A pulsar is a highly magnetized rapidly rotating neutron star. Weighing more than our Sun, yet only about 20 km in diameter, these incredibly dense objects produce radio beams that sweep the sky like a lighthouse. Pulsars ...
  • Study on phasing of segmented mirrors using the dispersed fringe technique 
    Radhika, Dharmadhikari (Indian Institute of Astrophysics, 2020-07)
    The segmented mirror technology is being extensively used these days in astronomical telescopes, in order to achieve higher resolution and sensitivity with lower manufacturing costs. To make the segments work like a ...
  • Variation of chromospheric features as a function of latitude and time using Ca-K spectroheliograms for solar cycles 15 - 23: Implications for meridional flow 
    Devi, Pooja; Singh, J; Chandra, Ramesh; Priyal, Muthu; Joshi, Reetika (Springer, 2021-03)
    We have analyzed the Ca-K images obtained at Kodaikanal Observatory as a function of latitude and time for the period of 1913 - 2004 covering Solar Cycles 15 to 23. We have classified the chromospheric activity into plage, ...
  • Interacting system NGC 7805/6 (Arp 112) and its tidal dwarf galaxy candidate 
    Fu, Zhen-Xing; Sengupta, Chandreyee; Ramya, S; Pradhan, Bikram; Singh, Mridweeka; Misra, K; Scott, Tom. C; Ma, Yin-Zhe (IOP Publishing, 2021-02)
    We present results from our Giant Metrewave Radio Telescope (GMRT) Hi, Himalayan Chandra Telescope (HCT) Hα, 1 m Sampurnanand Telescope (ST) and 1.3 m Devasthal Fast Optical Telescope (DFOT) deep optical observations of ...
  • Comet tales from India: Donati's Comet of 1858 (C/1858 L1 Donati) 
    Kapoor, R. C (National Astronomical Research Institute of Thailand, 2021-03)
    On 02 June 1858 at the Observatory of Florence, Giambattista Donati (1826–1873) discovered a faint nebulous patch what was destined to become one of the most brilliant comets in history. Named after him, Donati’s Comet ...
  • High-redshift narrow-line Seyfert 1 galaxies: a candidate sample 
    Rakshit, S; Stalin, C. S; Kotilainen, Jari; Shin, Jaejin (IOP Publishing, 2021-03)
    The study of narrow-line Seyfert 1 galaxies (NLS1s) is now mostly limited to low redshift (z < 0.8) because their definition requires the presence of the Hβ emission line, which is redshifted out of the spectral coverage ...
  • Tracing young star-forming clumps in the nearby flocculent spiral galaxy NGC 7793 with UVIT imaging 
    Mondal, Chayan; Subramaniam, A; George, Koshy; Postma, Joseph E; Subramanian, S; Barway, Sudhanshu (IOP Publishing, 2021-03-10)
    Star formation in galaxies is a hierarchical process with a wide range of scales, from smaller clusters to larger stellar complexes. Here, we present an ultra-violet imaging study of the nearby flocculent spiral galaxy NGC ...
  • The Globular cluster M10: reassessment of stellar membership, distance, and age using its variable and HB stars 
    Arellano Ferro, A; Yepez, M. A; Muneer, S; Bustos Fierro, I. H; Schroder, K. P; Giridhar, S; Calderon, J. H (Oxford University Press on behalf of the Royal Astronomical Society, 2020-12)
    Time-series VI CCD photometry of the globular cluster M10 (NGC 6254) is employed to perform a detailed identification, inspection of their light curves, their classification, and their cluster membership, of all the known ...
  • The Intrinsic reddening of the Magellanic Clouds as traced by background galaxies – II. The Small Magellanic Cloud 
    Bell, C. P. M; Cioni, Maria-Rosa L; Wright, A. H; Rubele, Stefano; Nidever, David L; Tatton, Ben L; van Loon, Jacco Th; Zaritsky, Dennis; Choi, Yumi; Choudhury, Samyaday; Clementini, Gisella; de Grijs, Richard; Ivanov, Valentin D; Majewski, Steven R; Marconi, Marcella; Martinez-Delgado, David; Massana, Pol; Munoz, Ricardo R; Niederhofer, Florian; Noel, Noelia E D; Oliveira, Joana M; Olsen, Knut; Pennock, Clara M; Ripepi, V; Subramanian, S; Katherina Vivas, A (Oxford University Press on behalf of the Royal Astronomical Society, 2020-11)
    We present a map of the total intrinsic reddening across ≃34 deg2 of the Small Magellanic Cloud (SMC) derived using optical (ugriz) and near-infrared (IR; YJKs) spectral energy distributions (SEDs) of background galaxies. ...
  • Discovery and rapid follow-up observations of the unusual type II SN 2018ivc in NGC 1068 
    Bostroem, K. A; Valenti, S; Sand, D. J; Andrews, J. E; Van Dyk, S. D; Galbany, L; Pooley, D; Amaro, R. C; Smith, N; Yang, S; Anupama, G. C; Arcavi, I; Baron, E; Brown, P. J; Burke, J; Cartier, R; Hiramatsu, D; Dastidar, R; DerKacy, J. M; Dong, Y; Egami, E; Ertel, S; Filippenko, A. V; Fox, O. D; Haislip, J; Hosseinzadeh, G; Howell, D. A; Gangopadhyay, A; Jha, S. W; Kouprianov, V; Kumar, B; Lundquist, M; Milisavljevic, D; McCully, C; Milne, P; Misra, K; Reichart, D. E; Sahu, D. K; Sai, H; Singh, A; Smith, P. S; Vinko, J; Wang, X; Wang, Y; Wheeler, J. C; Williams, G. G; Wyatt, S; Zhang, J; Zhang, X (IOP Publishing, 2020-05-20)
    We present the discovery and high-cadence follow-up observations of SN 2018ivc, an unusual SNe II that exploded in NGC 1068 (D = 10.1 Mpc). The light curve of SN 2018ivc declines piecewise-linearly, changing slope ...
  • Importance of angle-dependent partial frequency redistribution in hyperfine structure transitions under the incomplete paschen–back effect regime 
    Nagendra, K.N.; Sowmya, K; Sampoorna, M; Stenflo, J.O.; Anusha, L.S. (IOP Publishing, 2020-07-20)
    Angle-frequency coupling in scattering of polarized light on atoms is represented by the angle-dependent (AD) partial frequency redistribution (PRD) matrices. There are several lines in the linearly polarized solar spectrum, ...
  • Effects of thermal emission on the transmission spectra of hot Jupiters 
    Chakrabarty, Aritra; Sengupta, S (IOP Publishing, 2020-07-20)
    The atmosphere on the dayside of a highly irradiated close-in gas giant (also known as a hot Jupiter) absorbs a significant part of the incident stellar radiation, which again gets re-emitted in the infrared wavelengths ...
  • Analysis of full-disc Ca II K spectroheliograms III. Plage area composite series covering 1892–2019 
    Chatzistergos, Theodosios; Ermolli, Ilaria; Krivova, Natalie A; Solanki, Sami K; Banerjee, D; Barata, Teresa; Belik, Marcel; Gafeira, Ricardo; Garcia, Adriana; Hanaoka, Yoichiro; Manjunath, H; Klimes, Jan; Korokhin, Viktor V; Lourenço, Ana; Malherbe, Jean-Marie; Marchenko, Gennady P; Peixinho, Nuno; Sakurai, Takashi; Tlatov, Andrey G (EDP Sciences, 2020-07)
    Context. Studies of long-term solar activity and variability require knowledge of the past evolution of the solar surface magnetism. The archives of full-disc Ca II K observations that have been performed more or less ...
  • The completed SDSS-IV extended baryon oscillation spectroscopic survey: BAO and RSD measurements from the anisotropic power spectrum of the quasar sample between redshift 0.8 and 2.2 
    Neveux, Richard; Burtin, Etienne; Mattia, Arnaud de; Smith, Alex; Ross, Ashley J; Hou, Jiamin; Bautista, Julian; Brinkmann, Jonathan; Chuang, Chia-Hsun; Dawson, Kyle S; Gil-Marin, Hector; Lyke, Brad W; Macorra, Axel de la; Bourboux, Helion du Mas des; Mohammad, Faizan G; Muller, Eva-Maria; Myers, Adam D; Newman, Jeffrey A; Percival, Will J; Rossi, Graziano; Schneider, Donald; Vivek, M; Zarrouk, Pauline; Zhao, Cheng; Zhao, Gong-Bo (Oxford University Press on behalf of the Royal Astronomical Society, 2020-11)
    We measure the clustering of quasars of the final data release (DR16) of eBOSS. The sample contains 343708 quasars between redshifts 0.8 ≤ z ≤ 2.2 over 4699deg2⁠. We calculate the Legendre multipoles (0,2,4) of the anisotropic ...
  • Alleviating the H0 and σ8 anomalies with a decaying dark matter model 
    Pandey, Kanhaiya L; Karwal, Tanvi; Das, Subinoy (IOP Publishing, 2020-07)
    The Hubble tension between the ΛCDM-model-dependent prediction of the current expansion rate H0 using Planck data and direct, model-independent measurements in the local universe from the SH0ES collaboration disagree at ...

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