IIA Institutional Repository: Recent submissions

  • Investigation of the correlation between optical and γ-ray flux variation in the blazar Ton 599 
    Rajput, Bhoomika; Mandal, Amit Kumar; Pandey, Ashwani; Stalin, C. S; Max-Moerbeck, Walter; Mathew, Blesson (Published by Oxford University Press on behalf of Royal Astronomical Society, 2024-02)
    The correlation between optical and γ-ray flux variations in blazars reveals a complex behaviour. In this study, we present our analysis of the connection between changes in optical and γ-ray emissions in the blazar Ton ...
  • UOCS. XIII. Study of the Far-ultraviolet Bright Stars in the Open Cluster NGC 2420 Using AstroSat 
    Yadav, R. K. S; Dattatrey, Arvind K; Rangwal, Geeta; Subramaniam, A; Bisht, D; Sagar, R (American Astronomical Society, 2024-02-01)
    We present the study of four far-ultraviolet (FUV) bright stars in the field of the open cluster NGC 2420 using the Ultra Violet Imaging Telescope mounted on AstroSat. The three stars 525, 527, and 560 are members, while ...
  • Filament Eruption from Active Region 13283 Leading to a Fast Halo-CME and an Intense Geomagnetic Storm on 2023 April 23 
    Vemareddy, P (American Astronomical Society, 2024-02-01)
    Using multi-instrument and multiwavelength observations, we studied a coronal mass ejection (CME) that led to an intense geomagnetic storm on 2023 April 23. The eruption occurred on April 21 in solar active region (AR) ...
  • Unravelling the nature of explosion of thermonuclear supernovae 
    Dutta, Anirban (Indian Institute of Astrophysics, 2023-05)
    Type Ia supernovae (SNe Ia) result from thermonuclear explosions in binary systems consisting of at least one carbon-oxygen white dwarf. They are crucial for the understanding of galactic chemical composition as they are ...
  • High precision spectroscopy using stabilized Fabry-Perot Etalon 
    Das, Tanya (Indian Institute of Astrophysics, 2021)
    Accurate wavelength calibration is an important factor for any measure ment with high resolution spectrographs. Stellar spectrum comprises of dis crete absorption or emission lines whose position is precisely determined ...
  • Investigating the ultra-violet bright stars in star clusters 
    Rani, Sharmila (Indian Institute of Astrophysics, 2023-02)
    Star clusters are gravitationally bound systems composed of a large number of stars, ranging from thousands to millions. As the dynamic age of the cluster is less than the age of the universe, dynamical interactions ...
  • W. M. Keck observatory instrumentation status and future direction 
    Kassis, Marc; Allen, Steven L; Alverez, Carlos; Baker, Ashley; Banyal, Ravinder K; Bertz, Robert; Beichman, Charles; Brown, Aaron; Brown, Matthew; Bundy, Kevin; Cabak, Gerald; Cetre, Sylvain; Chin, Jason; Chun, Mark R; Cooke, Jeff; Delorme, Jacques; Deich, William; Dekany, Richard G; Devenot, Mark; Doppmann, Greg; Edelstein, Jerry; Fitzgerald, Michael P; Fucik, Jason R; Gao, Maodong; Gibson, Steve; Gillingham, Peter R; Gomez, Percy; Gottschalk, Colby; Halverson, Sam; Hill, Grant; Hinz, Philip; Holden, Bradford P; Howard, Andrew W; Jones, Tucker; Jovanovic, Nemanja; Kirby, Evan; Krishnan, Shanti; Kupke, Renate; Lanclos, Kyle; Larkin, James E; Leifer, Stephanie D; Lewis, Hilton A; Lilley, Scott; Lu, Jessica R; Lyke, James E; MacDonald, Nicholas; Martin, Christopher; Mather, John; Matuszewski, Mateusz; Mawet, Dimitri; McCarney, Ben; McGurk, Rosalie; Marin, Eduardo; Millar-Blanchaer, Maxwell A; Nance, Craig; Nash, Reston B; Neill, James D; O'Meara, John M; Peretz, Eliad; Poppett, Claire; Konopacky, Quinn; Radovan, Matthew V; Ragland, Sam; Rider, Kodi; Roberts, Mitsuko; Rockosi, Constance; Rubenzahl, Ryan; Sallum, Stephanie; Sandford, Dale; Savage, Maureen; Simha, Sunil; Skemer, Andy J; Steidel, Charles C; Stelter, Richard D; Surendran, Avinash; Walawender, Josh; Westfall, Kyle B; Wizinowich, Peter; Wright, Shelley; Yeh, Sherry (Wiley-VCH GmbH, 2023-10)
    Since the start of science operations in 1993, the twin 10-m W. M. Keck Observatory (WMKO) telescopes have continued to maximize their scientific impact and to produce transformative discoveries that keep the observing ...
  • β-SGP: Scaled Gradient Projection with β-divergence for astronomical image restoration 
    Gondhalekar, Y; Safonova, M; Saha, S (Elsevier B.V., 2023-07)
    Image restoration in astronomy has been considered a vital step in many ground-based observational programs that often suffer from sub-optimal seeing due to atmospheric turbulence, distortion of stellar shapes due to ...
  • Building a large affordable optical-NIR telescope (I): an alternate way to handle segmented primary mirror 
    Radhika, Dharmadhikari; Parihar, P; Jacob, A (Springer Nature, 2023-12)
    The use of innovative ideas and the latest technology have undoubtedly brought down telescope costs substantially. However, there are still ways to further reduce the cost of optical ground-based telescopes and make them ...
  • Statistical properties of galactic synchrotron temperature and polarization maps — a multi-frequency comparison 
    Fazlu, Rahman; Pravabati, C; Ghosh, Tuhin (IOP Publishing, 2024-01)
    Understanding the statistical properties of synchrotron emission from our Galaxy is valuable from the perspective of observations targeting signals of cosmological origin, as well as for understanding physical processes ...
  • Possibilities of identifying members from Milky Way satellite galaxies using unsupervised machine learning algorithms 
    Divakar, Devika K; Saraf, Pallavi; Sivarani, T; Doddamani, Vijayakumar H (Indian Academy of Sciences, 2024-06)
    A detailed study of stellar populations in Milky Way (MW) satellite galaxies remains an observational challenge due to their faintness and fewer spectroscopically confirmed member stars. We use unsupervised machine learning ...
  • Differential Rotation of the Solar Chromosphere: A Century-long Perspective from Kodaikanal Solar Observatory Ca II K Data 
    Mishra, Dibya Kirti; Routh, Srinjana; Jha, Bibhuti K; Chatzistergos, Theodosios; Basu, Judhajeet; Chatterjee, Subhamoy; Banerjee, D; Ermolli, Ilaria (American Astronomical Society, 2024-01-20)
    Chromospheric differential rotation is a key component in comprehending the atmospheric coupling between the chromosphere and the photosphere at different phases of the solar cycle. In this study, we therefore utilize the ...
  • Characterizing the Ordinary Broad-line Type Ic SN 2023pel from the Energetic GRB 230812B 
    Srinivasaragavan, Gokul P; Swain, Vishwajeet; O’Connor, Brendan; Anand, Shreya; Ahumada, Tomás; Perley, Daniel; Stein, Robert; Sollerman, Jesper; Fremling, Christoffer; Cenko, S. Bradley; Antier, S; Guessoum, Nidhal; Hussenot-Desenonges, Thomas; Hello, Patrice; Lesage, Stephen; Hammerstein, Erica; Miller, M. Coleman; Andreoni, Igor; Bhalerao, Varun; Bloom, Joshua S; Dutta, Anirban; Gal-Yam, Avishay; Hinds, K-Ryan; Jaodand, Amruta; Kasliwal, Mansi; Kumar, Harsh; Kutyrev, Alexander S; Ragosta, Fabio; Ravi, Vikram; Sharma, Kritti; Teja, Rishabh Singh; Yang, Sheng; Anupama, G. C; Bellm, Eric C; Coughlin, Michael W; Mahabal, Ashish A; Masci, Frank J; Pathak, Utkarsh; Purdum, Josiah; Roberts, Oliver J; Smith, Roger; Wold, Avery (American Astronomical Society, 2024-01-10)
    We report observations of the optical counterpart of the long gamma-ray burst (GRB) GRB 230812B and its associated supernova (SN) SN 2023pel. The proximity (z = 0.36) and high energy (Eγ,iso ∼ 1053 erg) make it an important ...
  • Classification and characterization using HCT/HFOSC spectra of carbon stars selected from the HES survey 
    Meenakshi, P; Goswami, A (Springer, 2024-01)
    We present results from the analysis of 88 carbon stars selected from Hamburg/ESO (HES) survey using low-resolution spectra (R ∼1330 & 2190). The spectra were obtained with the Himalayan Faint Object Spectrograph Camera ...
  • Impact of two severe geomagnetic storms on the ionosphere over Indian longitude sector during March-April 2023 
    Rajana, Siva Sai Kumar; Panda, Sampad Kumar; Jade, Sridevi; Vivek, Chiranjeevi G; Upadhayaya, A.K; Bhardwaj, Arti; Jorphail, S; Seemala, Gopi Krishna (Springer, 2024-01)
    We investigated the ionosphere response to the two severe geomagnetic storms in the ascending phase of solar cycle 25 which occurred during the 23-24 March 2023 (SYM-Hmin = −169 nT) and 23-24 April 2023 (SYM-Hmin = −233 ...
  • Origin of the broadband emission from the transition blazar B2 1308+326 
    Pandey, Ashwani; Kushwaha, Pankaj; Wiita, Paul J; Prince, Raj; Czerny, Bożena; Stalin, C. S (EDP Sciences, 2024-01)
    Context. Transition blazars exhibit a shift from one subclass to the next during different flux states. It is therefore crucial to study them to understand the underlying physics of blazars. Aims. We probe the origin of ...
  • Unravelling the post-collision properties of the Cartwheel galaxy: A MUSE exploration of its bar and inner region 
    Mondal, Chayan; Barway, Sudhanshu (EDP Sciences, 2024-01)
    Aims. We aim to investigate the characteristics of the bar and inner disc in the collisional ring galaxy Cartwheel. Methods. We used integral field unit (IFU) observations from the Multi-Unit Spectroscopic Explorer (MUSE) ...
  • Shooting for the stars 
    India Today (2024-01-01)
  • UOCS – XI. Study of blue straggler stars in open cluster NGC 7142 using UVIT/AstroSat 
    Panthi, Anju; Vaidya, Kaushar; Vernekar, Nagaraj; Subramaniam, A; Jadhav, Vikrant; Agarwal, Manan (Oxford University Press on behalf of Royal Astronomical Society, 2024-01)
    We present a study of blue straggler stars (BSSs) of open cluster NGC 7142 using AstroSat/UVIT data and other archival data. Using a machine-learning-based algorithm, ML-MOC, on Gaia DR3 data, we find 546 sources as cluster ...
  • Narrow-line Seyfert 1 galaxies in Sloan Digital Sky Survey: a new optical spectroscopic catalogue 
    Paliya, Vaidehi S; Stalin, C. S; Dominguez, Alberto; Saikia, D. J (Oxford University Press on behalf of Royal Astronomical Society, 2024-01)
    Narrow-line Seyfert 1 (NLSy1) galaxies are an enigmatic class of active galactic nuclei (AGN) that exhibit peculiar multiwavelength properties across the electromagnetic spectrum. For example, these sources have allowed ...

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