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Browsing by Author "Raj, A"

Browsing by Author "Raj, A"

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  • Binarity among objects with the Be and B[e] phenomena 
    Miroshnichenko, A. S; Zharikov, S.V; Korcakova, D; Manset, N; Mennickent, R; Khokhlov, S. A; Danford, S; Raj, A; Zakhozhay, O.V (Astronomical Institute of the Slovak Academy of Sciences, 2020-03)
    Many B-type stars exhibit two phenomena that are symbolized Be and B[e]. The former refers to presence of a circumstellar gaseous disk without significant circumstellar dust, while the latter have dust. Although neither ...
  • A Deep Study of the Open Cluster NGC 5288 Using Photometric and Astrometric Data from GAIA DR3 and 2MASS 
    Sethi, Ritika; Bisht, D; Rangwal, Geeta; Raj, A (Instituto de Astronomıa, Universidad Nacional Autonoma de Mexico, 2023-10)
    This paper investigates a poorly studied open cluster, NGC 5288, using 2MASS JHKS and the recently released Gaia DR3 astrometric and photometric data. The mean proper motions in right ascension and declination are estimated ...
  • First detection of a magnetic field in low-luminosity B[e] stars New scenarios for the nature and evolutionary stages of FS CMa stars 
    Korcakova, D; Sestito, F; Manset, N; Kroupa, P; Votruba, V; Slechta, M; Danford, S; Dvorakova, N; Raj, A; Chojnowski, S. D; Singh, H. P (EDP Sciences, 2022-03)
    We report the first detection of the magnetic field in a star of FS CMa type, a subgroup of objects characterized by the B[e] phenomenon. The split of magnetically sensitive lines in IRAS 17449+2320 determines the magnetic ...
  • Four years of starspot evolution on an active F-type ultra-fast rotator KIC 6791060 
    Karmakar, Subhajeet; Pandey, J. C; Savanov, Igor S; Raj, A; Dmitrienko, E. S; Pakhomov, Yurij; Sahu, D. K (Cambridge University Press, 2018-02)
    Using the data obtained from Kepler satellite, we have analyzed an F-type ultra-fast rotator KIC 6791060. We derive a rotational period of 0.34365±0.00004 d. Multiple periodicity with a period separation of ∼0.00016 d was ...
  • The intermediate polar cataclysmic variable GK Persei 120 years after the nova explosion: a first dynamical mass study 
    Alvarez-Hernandez, A; Torre, M. A. P; Rodriguez-Gil, P; Shahbaz, T; Anupama, G. C; Gazeas, K. D; Pavana, M; Raj, A; Hakala, P; Stone, G; Gomez, S; Jonker, P. G; Ren, J.- J; Cannizzaro, G; Pastor-Marazuela, I; Goff, W; Corral-Santana, J. M; Sabo, R (Oxford University Press on behalf of Royal Astronomical Society, 2021-11)
    We present a dynamical study of the intermediate polar and dwarf nova cataclysmic variable GK Persei (Nova Persei 1901) based on a multisite optical spectroscopy and R-band photometry campaign. The radial velocity curve ...
  • Multi-band behaviour of the TeV blazar PG 1553+113 in optical range on diverse timescales 
    Agarwal, A; Mihov, B; Andruchow, I; Cellone, S. A; Anupama, G. C; Agrawal, V; Zola, S; Slavcheva, L; Slavcheva-Mihova, L; Ozdonmez, A; Ege, Ergun; Raj, A; Mammana, L; Zibecchi, L; Fernandez-Lajus, E (EDP Sciences, 2021-01)
    Context. The TeV BL Lac object PG 1553+113 is one of the primary candidates for a binary supermassive black hole system. Aims. We study the flux and spectral variability of PG 1553+113 on intra-night to long-term ...
  • Multiband optical variability of 3C 279 on diverse time scales 
    Aditi Agarwal; Cellone, Sergio A; Andruchow, I; Mammana, Luis; Singh, Mridweeka; Anupama, G. C; Mihov, B; Raj, A; eva-Mihova, L; Ozdonmez, Aykut; Ege, Ergun (Oxford University Press on behalf of the Royal Astronomical Society, 2019-09)
    We have monitored the flat spectrum radio quasar, 3C 279, in the optical B, V, R, and I passbands from 2018 February to 2018 July for 24 nights, with a total of 716 frames, to study flux, colour, and spectral variability ...
  • Multiband optical variability of 3C 279 on diverse time-scales 
    Agarwal, A; Cellone, S. A; Andruchow, Ileana; Mammana, Luis; Mridweeka Singh; Anupama, G. C; Mihov, B; Raj, A; Slavcheva-Mihova, L; Ozdonmez, Aykut; Ege, Ergun (Oxford University Press on behalf of the Royal Astronomical Society, 2019-09)
    We have monitored the flat spectrum radio quasar, 3C 279, in the optical B, V, R, and I passbands from 2018 February to 2018 July for 24 nights, with a total of 716 frames, to study flux, colour, and spectral variability ...
  • On the long-cycle variability of the Algol OGLE-LMC-DPV-065 and its stellar, orbital, and disc parameters 
    Mennickent, R. E; Cabezas, M; Djurasevic, G; Rivinius, T; Hadrava, P; Poleski, R; Soszynski, I; Celedon, L; Astudillo-Defru, N; Raj, A; Fernandez-Trincado, J. G; Schmidtobreick, L; Tappert, C; Neustroev, V; Porritt, I (Oxford University Press on behalf of the Royal Astronomical Society, 2019-08)
    OGLE-LMC-DPV-065 is an interacting binary whose double-hump long photometric cycle remains hitherto unexplained. We analyze photometric time series available in archive data sets spanning 124 yr and present the analysis ...
  • Optical and Near-infrared Study of Nova V2676 Oph 2012 
    Raj, A; Das, R. K; Walter, F. M (IOP Publishing, 2017-02-01)
    We present optical spectrophotometric and near-infrared (NIR) photometric observations of the nova V2676 Oph covering the period from 2012 March 29 through 2015 May 8. The optical spectra and photometry of the nova have ...
  • A search for QPOs in the lazar OJ287: preliminary results from the 2015/2016 observing campaign 
    Zola, S; Valtonen, M; Bhatta, G; Goyal, A; Debski, B; Baran, A; Krzesinski, J; Siwak, M; Ciprini, S; Gopakumar, A; Jermak, H; Nilsson, K; Reichart, D; Matsumoto, K; Sadakane, K; Gazeas, K; Kidger, M; Piirola, V; Alicavus, F; Baliyan, K. S; Berdyugin, A; Boyd, D; Campas Torrent, M; Campos, F; Carrillo G-mez, J; Caton, D. B; Chavushyan, V; Dalessio, J; Dimitrov, D; Drozdz, M; Er, H; Erdem, A; Escartin Perez, A; Fallah Ramazani, V; Filippenko, A. V; Garcia, F; Gomez Pinilla, F; Maheswar, G; Haislip, J. B; Harmanen, J; Hudec, R; Hurst, G; Ivarsen, K. M; Jelinek, M; Joshi, A; Kagitan, M; Kaur, N; Keel, W. C; LaCluyze, A. P; Lee, B. C; Lindfors, E; Lozano de Haro, J; Moore, J. P; Mugrauer, M; Naves Nogues, R; Neely, A. W; Nelson, R. H; Ogloza, W; Okano, S; Pandey, J. C; Perri, M; Pihajoki, P; Poyner, G; Provencal, J; Pursimo, T; Raj, A; 29 others (Molecular Diversity Preservation International, 2016-12)
    We analyse the light curve in the R band of the blazar OJ287, gathered during the 2015/2016 observing season. We did a search for quasi-periodic oscillations (QPOs) using several methods over a wide range of timescales. ...
  • Spectroscopic and geometrical evolution of the ejecta of the classical nova ASASSN-18fv 
    Pavana, M; Raj, A; Bohlsen, T; Anupama, G. C; Gupta, R; Selvakumar, G (Oxford University Press on behalf of the Royal Astronomical Society, 2020-05)
    The optical spectroscopic observations of ASASSN-18fv observed from 2018 March 24 to 2019 January 26 are presented. The optical spectra are obtained from Mirranook, Vainu Bappu, and South African Astronomical observatories. ...
  • Spectroscopic and geometrical evolution of the ejecta of the classical nova ASASSN-18fv 
    Pavana, M; Raj, A; Bohlsen, T; Anupama, G. C; Gupta, R; Selvakumar, G (Oxford University Press on behalf of the Royal Astronomical Society, 2020-06)
    The optical spectroscopic observations of ASASSN-18fv observed from 2018 March 24 to 2019 January 26 are presented. The optical spectra are obtained from Mirranook, Vainu Bappu, and South African Astronomical observatories. ...
  • Stochastic modeling of multiwavelength variability of the classical BL Lac Object OJ 287 on timescales ranging from decades to hours 
    Goyal, A; Stawarz, L; Zola, S; Marchenko, V; Soida, M; Nilsson, K; Ciprini, S; Baran, A; Ostrowski, M; Wiita, P. J; Gopal-Krishna; iemiginowska, A; Sobolewska, M; Jorstad, S; Marscher, A; Aller, M. F; Aller, H. D; Hovatta, T; Caton, D. B; Reichart, D; Matsumoto, K; Sadakane, K; Gazeas, K; Kidger, M; Piirola, V; Jermak, H; Alicavus, F; Baliyan, K. S; Baransky, A; Berdyugin, A; Blay, P; Boumis, P; Boyd, D; Bufan, Y; Campas Torrent, M; Campos, F; Carrillo Gomez, J; Dalessio, J; Debski, B; Dimitrov, D; Drozdz, M; Er, H; Erdem, A; Escartin Perez, A; Fallah Ramazani, V; Filippenko, A. V; Gafton, E; Garcia, F; Godunova, V; Gomez Pinilla, F; Maheswar, G; Haislip, J. B; Haque, S; Harmanen, J; Hudec, R; Hurst, G; Ivarsen, K. M; Joshi, A; Kagitani, M; Karaman, N; Karjalainen, R; Kaur, N; Koziel-Wierzbowska, D; Kuligowska, E; Kundera, T; Kurowski, S; Kvammen, A; LaCluyze, A. P; Lee, B. C; Liakos, A; Lozano de Haro, J; Moore, J. P; Mugrauer, M; Naves Nogues, R; Neely, A. W; Ogloza, W; Okano, S; Pajdosz, U; Pandey, J. C; Perri, M; Poyner, G; Provencal, J; Pursimo, T; Raj, A; and 29 co-authors (IOP Publishing, 2018-08-20)
    We present the results of our power spectral density analysis for the BL Lac object OJ 287, utilizing the Fermi-LAT survey at high-energy γ-rays, Swift-XRT in X-rays, several ground-based telescopes and the Kepler satellite ...
  • V2676 Oph: Estimating Physical Parameters of a Moderately Fast Nova 
    Raj, A; Pavana, M; Kamath, U. S; Anupama, G. C; Walter, F. M (Copernicus Foundation for Polish Astronomy, 2018-03)
    Using our previously reported observations, we derive some physical parameters of the moderately fast nova V2676 Oph 2012 #1. The best-fit CLOUDY model of the nebular spectrum obtained on 2015 May 8 shows a hot white dwarf ...
  • X-ray confirmation of the intermediate polar IGR J16547-1916 
    Joshi, A; Wang, W; Pandey, J. C; Singh, K. P; Naik, S; Raj, A; Anupama, G. C; Rawat, N (EDP Sciences, 2022-01)
    Using X-ray observations from the NuSTAR and Swift satellites, we present temporal and spectral properties of an intermediate polar (IP) IGR J16547-1916. A persistent X-ray period at ∼546 s confirming the optical spin ...

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