IIA Institutional Repository: Recent submissions

  • 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 ...
  • Towards the development of the Infrared Guide Star Catalogue for the adaptive optics observations by the Thirty Meter Telescope 
    Shah, Sarang; Subramanian, S; Anupama, G. C; Delgado, Francisco; Gillies, Kim; Maheswar, G; Narayanan, Rajalakshmi; Ramaprakash, A. N; Rao, Suhasini; Reddy, B. E; Skidmore, Warren; Sivarani, T; Subramaniam, A (SPIE-The International Society for Optical Engineering, 2022-08)
    At first light, the NIR instruments of TMT will be assisted by a multi-conjugate adaptive optics instrument, known as the Narrow Field Infrared Adaptive Optics System (NFIRAOS). NFIRAOS will use laser guide stars for ...
  • Aspects of Design and Development of a Near Infrared Photometer for Low Altitude Astronomical Sites 
    Anwesh Kumar, M (Indian Institute of Astrophysics, 2021-01)
    In order to fill the void of observation of bright near infrared astronomical sources, we propose a Near Infrared photometer operating from a low latitude astronomical site. As part of this thesis work, design decisions ...
  • Studies on metal-poor stars and chemical enrichment of the Galaxy 
    Shejeelammal, J (Indian Institute of Astrophysics, 2022-06)
    The low- and intermediate-mass stars are the major inhabitants of our Galaxy. They play an important role in the chemical evolution of the Galaxy. These stars have enriched the ISM with the products of various nucleosynthesis ...
  • High precision radial velocity studies on VBT echelle spectrograph 
    Sireesha, C (Indian Institute of Astrophysics, 2019-08)
    The Echelle spectrograph operating at Vainu Bappu Telescope (VBT) is a general-purpose instrument designed for high-resolution spectroscopy. It was considered for precision Radial Velocity (RV) measurements without altering ...
  • Host galaxy magnitude of OJ 287 from its colours at minimum light 
    Valtonen, Mauri J; Dey, Lankeswar; Zola, S; Ciprini, S; Kidger, M; Pursimo, T; Gopakumar, A; Matsumoto, K; Sadakane, K; Caton, D. B; Nilsson, K; Komossa, S; Bagaglia, M; Baransky, A; Boumis, P; Boyd, D; Castro-Tirado, A. J; Debski, B; Drozdz, M; Perez, A. Escartin; Fiorucci, M; Garcia, F; Gazeas, K; Ghosh, S; Godunova, V; Gomez, J. L; Gredel, R; Grupe, D; Haislip, J. B; Henning, T; Hurst, G; Janík, J; Kouprianov, V. V; Lehto, H; Liakos, A; Mathur, S; Mugrauer, M; Nogues, R. Naves; Nucciarelli, G; Ogloza, W; Ojha, D. K; Pajdosz-Śmierciak, U; Pascolini, S; Poyner, G; Reichart, D. E; Rizzi, N; Roncella, F; Sahu, D. K; Sillanpää, A; Simon, A; Siwak, M; Alfaro, F. C. Soldán; Sonbas, E; Tosti, G; Vasylenko, V; Webb, J. R; Zielinski, P (Oxford University Press on behalf of Royal Astronomical Society, 2022-08)
    OJ 287 is a BL Lacertae type quasar in which the active galactic nucleus (AGN) outshines the host galaxy by an order of magnitude. The only exception to this may be at minimum light when the AGN activity is so low that ...
  • Growth of disc-like pseudo-bulges in SDSS DR7 since z = 0.1 
    Ankit Kumar; Kataria, Sandeep Kumar (Oxford University Press on behalf of Royal Astronomical Society, 2022-08)
    Cosmological simulations predict more classical bulges than their observational counterparts in the local Universe. Here, we quantify evolution of the bulges since z = 0.1 using photometric parameters of nearly 39 000 ...
  • Radio Evolution of a Type IIb Supernova SN 2016gkg 
    Nayana, A. J; Chandra, Poonam; Krishna, Anoop; Anupama, G. C (American Astronomical Society, 2022-08-01)
    We present extensive radio monitoring of a Type IIb supernova (SN IIb), SN 2016gkg during t ∼ 8−1429 days postexplosion at frequencies ν ∼ 0.33−25 GHz. The detailed radio light curves and spectra are broadly consistent with ...
  • Properties of ubiquitous magnetic reconnection events in the lower solar atmosphere 
    Joshi, Jayant; van der Voort, Luc Rouppe, H. M (EDP Sciences, 2022-08)
    Context. Magnetic reconnection in the deep solar atmosphere can give rise to enhanced emission in the Balmer hydrogen lines, a phenomenon referred to as Ellerman bombs. Recent high-quality Hβ observations indicate that ...
  • Implications of an Extended Dark Energy Model with Massive Neutrinos 
    Sharma, Ravi Kumar; Pandey, Kanhaiya L; Das, Subinoy (American Astronomical Society, 2022-08-01)
    Recently there have been reports of finding a lower bound on the neutrino mass parameter (Σmν) when using the Atacama Cosmology Telescope (ACT) and SPTpol data; however, these bounds on the Σmν are still weaker for most ...
  • 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 ...
  • On the origin of core radio emissions from black hole sources in the realm of relativistic shocked accretion flow 
    Das, Santabrata; Nandi, Anuj; Stalin, C. S; Rakshit, Suvendu; Dihingia, Indu Kalpa; Singh, Swapnil; Aktar, Ramiz; Mitra, Samik (Oxford University Press on behalf of Royal Astronomical Society, 2022-08)
    We study the relativistic, inviscid, advective accretion flow around the black holes and investigate a key feature of the accretion flow, namely the shock waves. We observe that the shock-induced accretion solutions are ...
  • The role of magnetic fields in the stability and fragmentation of filamentary molecular clouds: two case studies at OMC-3 and OMC-4 
    Li, Pak Shing; Lopez-Rodriguez, Enrique; Archana Soam; Klein, Richard I (Oxford University Press on behalf of Royal Astronomical Society, 2022-08)
    We present the stability analysis of two regions, OMC-3 and OMC-4, in the massive and long molecular cloud complex of Orion A. We obtained 214 μm HAWC + /SOFIA polarization data, and we make use of archival data for the ...
  • Spectroscopic Study of Four Metal-poor Carbon Stars from the Hamburg/ESO Survey: On Confirming the Low-mass Nature of Their Companions* 
    Shejeelammal, J; Goswami, A (American Astronomical Society, 2022-08-01)
    Elemental abundances of extrinsic carbon stars provide insight into the poorly understood origin and evolution of elements in the early Galaxy. In this work, we present the results of a detailed spectroscopic analysis of ...
  • The X-Ray and Radio Loud Fast Blue Optical Transient AT2020mrf: Implications for an Emerging Class of Engine-driven Massive Star Explosions 
    Yao, Yuhan; Ho, Anna Y. Q; Medvedev, Pavel; Nayana, A. J; Perley, Daniel A; Kulkarni, S. R; Chandra, Poonam; Sazonov, Sergey; Gilfanov, Marat; Khorunzhev, Georgii; Khatami, David K; Sunyaev, Rashid (American Astronomical Society, 2022-08-01)
    We present AT2020mrf (SRGe J154754.2+443907), an extra-galactic (z = 0.1353) fast blue optical transient (FBOT) with a rise time of tg,rise = 3.7 days and a peak luminosity of Mg,peak = −20.0. Its optical spectrum ...
  • Nature of helicity injection in non-erupting solar active regions 
    Vemareddy, P (Oxford University Press on behalf of Royal Astronomical Society, 2022-10)
    Using time-sequence vector magnetic field and coronal observations from Solar Dynamics Observatory, we report the observations of the magnetic field evolution and coronal activity in four emerging active regions (ARs). ...
  • Characterizing Solar Eruptions in Inner Corona using Ground and Space-based Data 
    Ritesh, Patel (Indian Institute of Astrophysics, 2021-08)
    The solar corona is known to be associated with eruptions of large amount of magnetized plasma into the interplanetary space. In-spite of several years of ground- and space-based observations of the solar atmosphere, the ...
  • Optimum design and development of segmented mirror telescope optics and phasing system 
    Jacob, A (Indian Institute of Astrophysics, 2020-10)
    Astronomy today is in the path of constructing large telescopes. Due to several manufacturing and maintenance difficulties, large telescopes of more than 8 m are predominantly segmented. To fulfill the need for its growing ...
  • Flux and spectral variability of Mrk 421 during its moderate activity state using NuSTAR: Possible accretion disc contribution? 
    Mondal, S; Priyanka Rani; Stalin, C. S; Chakrabarti, S. K; Rakshit, S (EDP Sciences, 2022-07)
    Context. The X-ray emission in BL Lac objects is believed to be dominated by synchrotron emission from their relativistic jets. However, when the jet emission is not strong, one could expect signatures of X-ray emission ...
  • Accretion disc sizes from continuum reverberation mapping of AGN selected from the ZTF survey 
    Jha, Vivek Kumar; Joshi, Ravi; Chand, Hum; Wu, Xue-Bing; Ho, Luis C; Rastogi, Shantanu; Ma, Qinchun (Oxford University Press on behalf of Royal Astronomical Society, 2022-04)
    We present the accretion disc-size estimates for a sample of 19 active galactic nuclei (AGNs) using the optical g-, r-, and i-band light curves obtained from the Zwicky Transient Facility survey. All the AGNs have reliable ...

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