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Browsing by Author "Shastri, P"

Browsing by Author "Shastri, P"

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  • A polarization study of three blazars using uGMRT at ∼600 MHz 
    Baghel, J; Silpa, S; Kharb, P; Sebastian, B; Shastri, P (Indian Academy of Sciences, 2022-12)
    We present results from our radio polarimetric study with the upgraded giant metrewave radio telescope (uGMRT) at band 4 (550–850 MHz) of three blazars: radio-loud quasars 3C390.3, 4C71.07 and BL Lac object 1ES 2344+514. ...
  • Probing the physics of narrow line regions in active galaxies. II. the siding spring southern seyfert spectroscopic snapshot survey (S7) 
    Dopita, M. A; Shastri, P; Davies, R; Kewley, L; Hampton, E; Scharwachter, J; Sutherland, R; Kharb, P; Jose, J; Bhatt, H. C; Ramya, S; Jin, C; Banfield, J; Zaw, I; Juneau, S; James, B; Shweta Srivastava (IOP Publishing, 2015-03)
    Here we describe the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) and present results on 64 galaxies drawn from the first data release. The S7 uses the Wide Field Spectrograph mounted on the ANU 2.3 m ...
  • Probing the physics of narrow-line regions in active galaxies. III. accretion and cocoon shocks in the liner NGC 1052 
    Dopita, M. A; Ho, I-Ting; Dressel, L. L; Sutherland, R; Kewley, L; Davies, R; Hampton, E; Shastri, P; Kharb, P; Jose, Jessy; Bhatt, H. C; Ramya, S; Scharwachter, J; Jin, C; Banfield, J; Zaw, I; James, B; Juneau, S; Srivastava, S (IOP Publishing, 2015-03-01)
    We present Wide Field Spectrograph integral field spectroscopy and Hubble Space Telescope Faint Object Spectrograph spectroscopy for the low-ionization nuclear emission line region (LINER) galaxy NGC 1052. We infer the ...
  • Probing the Physics of Narrow-line Regions in Active Galaxies. IV. Full Data Release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) 
    Thomas, A. D; Dopita, M. A; Shastri, P; Davies, R; Hampton, E; Kewley, L; Banfield, J; Groves, B; James, B. L; Jin, C; Juneau, S; Kharb, P; Lalitha, S; Scharwachter, J; Shalima, P; Sundar, M. N; Sutherland, R; Zaw, I (IOP Publishing, 2017-09)
    We present the second and final data release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). Data are presented for 63 new galaxies not included in the first data release, and we provide 2D ...
  • Probing the physics of narrow-line regions of Seyfert galaxies, I. The case of NGC 5427 
    Dopita, M. A; Scharwachter, J; Shastri, P; Kewley, L. J; Davies, R; Sutherland, R; Kharb, P; Jose, J; Hampton, E; Jin, C; Banfield, J; Basurah, H; Fischer, S (EDP Sciences, 2014-06)
    Context. The spectra of the extended narrow-line regions (ENLRs) of Seyfert 2 galaxies probe the physics of the central active galaxy nucleus (AGN), since they encode the energy distribution of the ionising photons, the ...
  • Probing the physics of Seyfert galaxies using their emission-line regions 
    Shastri, P; Dopita, M; Scharwachter, J; Kewley, L; Davies, R; Sutherland, R; Kharb, P; Banfield, J; Jose, J; Ramya, S; Srivastava, S; Bhatt, H. C; Hampton, E; Jin, J; Basurah, H; Fischer, S; Gupta, M; Panda, S; Sundar, M. N; Radhakrishnan, V (AIP Publishing, 2015-12)
    Active galaxies have powerhouses of radiation in their nuclear regions that are driven by accreting super-massive black holes. The accretion system also generates outflows of ionized gas and synchrotron-emitting bipolar ...
  • Radio and X-ray Emission from Low-Luminosity AGNs: Testing Unification Hypothesis 
    Singh, V; Shastri, P; Risaliti, G; Athreya, R (Astronomical Society of the Pacific, 2010-10)
    We investigate the low-frequency radio properties and the X-ray spectral properties of a sample of Seyfert galaxies in order to compare the two subtypes of Seyferts and rigorously test the predictions of Seyfert unification.
  • Relativistic beaming and central components of radio galaxies 
    Kharb, P; Shastri, P (Astronomical Society of India, 2001)
    We present results of our study of the parsec-scale components of radio galaxies as observed at radio and optical wavelengths, in the framework of the Unified Scheme.
  • The role of radiation pressure in the narrow line regions of Seyfert host galaxies 
    Davies, R. L; Dopita, M. A; Kewley, L; Groves, B; Sutherland, R; Hampton, E. J; Shastri, P; Kharb, P; Bhatt, H. C; Scharwachter, J; Jin, C; Banfield, J; Zaw, I; James, B; Juneau, S; Srivastava, S (IOP Publishing, 2016-06-10)
    We investigate the relative significance of radiation pressure and gas pressure in the extended narrow line regions (ENLRs) of four Seyfert galaxies from the integral field Siding Spring Southern Seyfert Spectroscopic ...
  • Rotation measures across parsec-scale jets of fanaroff-Riley Type I radio galaxies 
    Kharb, P; Gabuzda, D. C; O'Dea, C. P; Shastri, P; Baum, S. A (Institute of Physics, 2009-04)
    We present the results of a parsec-scale polarization study of three FRI radio galaxies—3C66B, 3C78, and 3C264—obtained with Very Long Baseline Interferometry at 5, 8, and 15 GHz. Parsec-scale polarization has been detected ...
  • S7 : Probing the physics of seyfert galaxies through their ENLR & HII regions 
    Dopita, M. A; Shastri, P; Scharwachter, J; Kewley, L. J; Davies, R; Sutherland, R; Kharb, P; Jose, Jessy; Bhatt, H. C; Ramya, S; Hamptona, E; Jina, C; Banfielda, J; Zawa, I; Srivastavaa, Shweta; Jamesa, B (Cambridge University Press, 2015-02)
    Here we present the first results from the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) which aims to investigate the physics of ∼140 radio-detected southern active Galaxies with z<0.02 through Integral ...
  • Seyfert Galaxies on milliarcsecond scales 
    Lal, D. V; Shastri, P; Gabuzda, D. C (Taylor and Francis, 2001-08)
    We present our results from global VLBI observations of a sample of Seyfert galaxies at 5 GHz. Our goal was to test predictions of the Unified Scheme for Seyfert galaxies, in which observed differences between Seyferts of ...
  • Seyfert Galaxies: Nuclear Radio Structure and Unification 
    Lal, D. V; Shastri, P; Gabuzda, D. C (IOP Publishing, 2011-04-10)
    A radio study of a carefully selected sample of 20 Seyfert galaxies that are matched in orientation-independent parameters, which are measures of intrinsic active galactic nucleus power and host galaxy properties, is ...
  • Seyfert Galaxies: Radio Continuum Emission Properties and the Unification Scheme 
    Singh, V; Shastri, P; Athreya, R (Indian Academy of Sciences, 2011-12)
    Seyfert galaxies are classified mainly into type 1 and type 2 depending on the presence and absence of broad permitted emission lines in their optical spectra, respectively. Unification scheme hypothesizes that the ...
  • Seyferts and their radio morphology 
    Shastri, P (Taylor and Francis, 2001-08)
    In this short review, current knowledge of the radio structure of Seyfert Galaxies is briefly outlined and its application in addressing 3 key debates, viz., the validity of the Unified Scheme, the validity of the starburst ...
  • Seyferts at milli-arcsec scales 
    Lal, D. V; Shastri, P; Gabuzda, D (Astronomical Society of India, 2000)
    We have observed a sample of Seyfert galaxies using Global Very Long Baseline Interferometry at 5 GHz. Our goal is to investigate the systematics of their nuclear radio morphology on milli-arcsecond scales. We have chosen ...
  • Spectroscopy of Seyferts in the Far-UV 
    Shastri, P; Murthy, J; Hutchings, J (Astronomical Society of India, 2003)
    We present our preliminary far-ultraviolet spectra of the Seyfert Mrk 533 obtained with FUSE. These are among the first FUV spectra of a purportedly edge-on Seyfert, and show narrow OVI emission as well as some evidence ...
  • Suzaku X-ray spectral study of the Compton-thick Seyfert galaxy NGC 5135 
    Singh, V; Risaliti, G; Braito, V; Shastri, P (Wiley-Blackwell, 2012-01)
    We present the 0.5–50 keV Suzaku broad-band X-ray spectral study of the Compton-thick active galactic nucleus (AGN) in NGC 5135. The Suzaku observation provides the first detection of NGC 5135 above 10 keV that allowed us, ...
  • Systematics of jets using multi-wavelength data 
    Shastri, P; Gomez, E. J; Gupta, M; Madejski, G (Cambridge University Press, 2015-03)
    We investigate the systematics of the properties of highly relativistic jets at multiple frequencies, including Fermi, and MOJAVE data. We test the hypothesis that the blazar divide constitutes a dichotomy. We also explore ...
  • Towards gender equity in physics in India: initiatives, investigations, and questions 
    Shastri, P; Kurup, A; Resmi, L; Ramaswamy, R; Ubale, S; Bagchi, S; Rao, S; Narasimhan, S (AIP Publishing, 2015-12)
    Initiatives towards gender parity in the sciences in India have occurred both at national, governmental levels and at local, institutional levels. A gender gap persists in physics, but data suggest that ...

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