Browsing by Title

Sort by: Order: Results:

  • 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) ...
  • Unravelling the unusually curved X-ray spectrum of RGB J0710 + 591 using AstroSat observations 
    Goswami, Pranjupriya; Sinha, Atreyee; Chandra, Sunil; Misra, Ranjeev; Chitnis, Varsha; Gogoi, Rupjyoti; Sahayanathan, Sunder; Stalin, C. S; Singh, K. P; Yada, J. S (Oxford University Press on behalf of the Royal Astronomical Society, 2020-02)
    We report the analysis of simultaneous multiwavelength data of the high-energy-peaked blazar RGB J0710 + 591 from the Large Area X-ray Proportional Counters, Soft X-ray focusing Telescope, and Ultraviolet Imaging ...
  • Unusual bright filaments on the sun on 1926 February 22 
    Royds, T (Royal Astronomical Society, 1926)
  • Unusual extinction profiles by Rayleigh scattering 
    Shah, G. A (WILEY-VCH Verlag Berlin GmbH & Co, 1977)
    The extinction efficiencies for small smooth metallic particles (granules) have been calculated using rigorous Mie theory of scattering. Strong size-dependent resonances for spheres composed of sodium, potassium, and calcium ...
  • Unusual long-term low-activity states of EGRET blazars in the Fermi era 
    Bhattacharya, Debbijoy; Mohana A, K; Gulati, S; Bhattacharyya, Subir; Bhatt, N; Sreekumar, P; Stalin, C. S (Oxford University Press on behalf of the Royal Astronomical Society, 2017-11)
    We examine the long-term (∼10 years) γ-ray variability of blazars observed by the Energetic Gamma Ray Experiment Telescope (EGRET) and Fermi and find that 10 EGRET-detected flat-spectrum radio quasars (FSRQs) were not ...
  • Unusual optical quiescence of the classical BL Lac object PKS 0735+178 on intranight time scale 
    Goyal, A; Gopal-Krishna; Anupama, G. C; Sahu, D. K; Sagar, R; Britzen, S; Karouzos, M; Aller, M. F; Aller, H. D (Wiley Blackwell, 2009-07)
    We present the result of our extensive intranight optical monitoring of the well known low-energy peaked BL Lac (LBL) object PKS 0735+178. This long-term follow-up consists of $R$-band monitoring for a minimum duration of ...
  • Unusual solar activity 
    Salaruddin, MD; Narayan, B. G (Calcutta University Press, 1939-12)
    The paper describes briefly the outstanding features of a recent persistent solar activity observed in Kodaikanal. Attempts have been made to correlate the bright chromospheric eruptions with the terrestrial effects. It ...
  • An unusual very low-mass high-amplitude pre-main sequence periodic variable 
    Rodríguez-Ledesma, M. V; Mundt, R; Ibrahimov, M; Messina, S; Parihar, P. S; Hessman, F. V; Alves de Oliveira, C; Herbst, W (EDP Sciences, 2012-08)
    Aims. We have investigated the nature of the variability of CHS 7797, an unusual periodic variable in the Orion Nebula Cluster. Methods. An extensive I-band photometric data set of CHS 7797 was compiled between 2004−2010 ...
  • The unusually large population of Blazhko variables in the globular cluster NGC 5024 (M53) 
    Arellano Ferro, A; Bramich, D. M; Figuera Jaimes, R; Giridhar, S; Kuppuswamy, K (Wiley-Blackwell, 2012-02)
    We report the discovery of amplitude and phase modulations typical of the Blazhko effect in 22 RRc and nine RRab type RR Lyrae stars in NGC 5024 (M53). This brings the confirmed Blazhko variables in this cluster to 23 RRc ...
  • Unveiling an Old Disk around a Massive Young Leaking Blueberry in SDSS-IV MaNGA 
    Paswan, Abhishek; Saha, Kanak; Borgohain, Anshuman; Leitherer, Claus; Dhiwar, Suraj (American Astronomical Society, 2022-04-10)
    Extreme emission-line galaxies, such as blue compact dwarfs (BCDs), Green Peas (GPs), and blueberries in the local universe are potential candidates for understanding the nature of galaxies that reionized the early universe. ...
  • Unveiling Vela – time variability of Na I D lines in the direction of the Vela supernova remnant 
    Kameswara Rao, N; Muneer, S; Lambert, D. L; Varghese, B. A (Oxford University Press on behalf of the Royal Astronomical Society, 2016-01-21)
    High-resolution spectral profiles of Na I D lines from the interstellar medium towards 64 stars in the direction of the Vela supernova remnant are presented. This survey conducted mostly between 2011 and 12 complements an ...
  • Unveiling Vela – variability of interstellar lines in the direction of the Vela supernova remnant – III. Na D and Ca II K 
    Kameswara Rao, N; Lambert, D. L; Reddy, A. B. S; Gupta, R; Muneer, S; Singh, H. P (Oxford University Press on behalf of the Royal Astronomical Society, 2020-03)
    High-resolution optical spectra were obtained in 2017–2019 with The Southern African Large Telescope of 15 stars in the direction of the Vela supernova remnant. Interstellar Ca II H & K and Na I D lines are discussed in ...
  • Unveiling Vela: time variability of interstellar lines in the direction of the Vela supernova remnant – II. Na D and Ca II 
    Kameswara Rao, N; Lambert, D. L; Reddy, A. B. S; Gupta, R; Muneer, S; Singh, H. P (IOP Publishing, 2017-05)
    In a survey conducted between 2011 and 2012 of interstellar Na I D line profiles in the direction of the Vela supernova remnant (SNR), a few lines of sight showed dramatic changes in low-velocity absorption components with ...
  • UOCS X. Rich collection of post-mass-transfer systems in NGC 6791 
    Jadhav, Vikrant V; Subramaniam, A; Sagar, Ram (EDP Sciences, 2023-08)
    Aims. NGC 6791 is one of the richest old open clusters in the Milky Way. Its position above the Galactic plane and its number density make it an interesting middle ground between Galactic open and globular clusters. We aim ...
  • UOCS – III. UVIT catalogue of open clusters with machine learning-based membership using Gaia EDR3 astrometry 
    Jadhav, Vikrant K; Pennock, C. M; Subramaniam, A; Sagar, R; Prasanta Kumar Nayak (Oxford University Press on behalf of the Royal Astronomical Society, 2021-05)
    We present a study of six open clusters (Berkeley 67, King 2, NGC 2420, NGC 2477, NGC 2682, and NGC 6940), using the Ultra Violet Imaging Telescope (UVIT) aboard ASTROSAT and Gaia EDR3. We used combinations of astrometric, ...
  • UOCS – VII. Blue straggler populations of open cluster NGC 7789 with UVIT/AstroSat 
    Vaidya, Kaushar; Panthi, Anju; Agarwal, Manan; Pandey, Sindhu; Khushboo Rao, K; Jadhav, Vikrant V; Subramaniam, A (Oxford University Press on behalf of Royal Astronomical Society, 2022-04)
    NGC 7789 is a ∼1.6 Gyr old, populous open cluster located at ∼2000 pc. We characterize the blue straggler stars (BSS) of this cluster using the Ultraviolet (UV) data from the UVIT/AstroSat. We present spectral energy ...
  • 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 ...
  • UOCS –VIII. UV study of the open cluster NGC 2506 using ASTROSAT 
    Panthi, Anju; Vaidya, Kaushar; Jadhav, Vikrant V; Khushboo Rao, K; Subramaniam, A; Agarwal, Manan; Pandey, Sindhu (Oxford University Press on behalf of Royal Astronomical Society, 2022-11)
    We study an intermediate-age open cluster (OC) NGC 2506 using the ASTROSAT/UVIT data and other archival data. We identified 2175 cluster members using a machine learning-based algorithm, ML–MOC, on Gaia EDR3 data. Among ...
  • UOCS-IX. AstroSat/UVIT Study of the Open Cluster NGC 2818: Blue Stragglers, Yellow Stragglers, Planetary Nebula, and their Membership 
    Sharmila Rani; Pandey, G; Subramaniam, A; Kameswara Rao, N (American Astronomical Society, 2023-03-01)
    We present the first far-UV (FUV) imaging results of the intermediate-age Galactic open cluster NGC 2818 that has a planetary nebula (PN) within the field using images taken from the Ultra Violet Imaging Telescope ...
  • UOCS. IV. discovery of diverse hot companions to blue stragglers in the old open cluster King 2 
    Jadhav, Vikrant V; Pandey, Sindhu; Subramaniam, A; Sagar, R (Indian Academy of Sciences, 2021-10)
    King 2, one of the oldest clusters in the Milky Way, with an age of ∼6 Gyr and distance of ∼5700 pc, has been observed with UVIT payload on the AstroSat. With membership information derived from Gaia EDR3, the cluster is ...

Search DSpace

Browse

My Account