Search Publications
Hard X-ray polarimetry—an overview of the method, science drivers, and recent findings
Chattopadhyay, Tanmoy
The last decade has seen a leapfrog in the interest of X-ray polarimetry with a number of new polarization measurements in hard X-rays from AstroSat, POLAR, GAP, and PoGO+. The measurements provide some interesting insights into various astrophysical phenomena such as coronal geometry and disk–jet connection in black hole X-ray binaries, hard X-ra…
UOCS. IV. Discovery of diverse hot companions to blue stragglers in the old open cluster King 2
Jadhav, Vikrant V.; Subramaniam, Annapurni; Pandey, Sindhu +1 more
King 2, one of the oldest clusters in the Milky Way, with an age of
The central region of the enigmatic Malin 1
Saha, Kanak; Barway, Sudhanshu; Dhiwar, Suraj +2 more
Malin 1, being a class of giant low surface galaxies, continues to surprise us even today. The HST/F814W observation has shown that the central region of Malin 1 is more like a normal SB0/a galaxy, while the rest of the disk has the characteristic of a low surface brightness system. The AstroSat/UVIT observations suggest scattered recent star form…
Characteristics of the open star cluster Kronberger 60 using Gaia DR2
Tadross, A. L.; Hendy, Y. H.
The estimation of the main parameters of star clusters is a very important target in astrophysical studies. Many of the open clusters listed in known catalogs have insufficient astrometric parameters. Improving the observations and analysis methods proved that some of them are asterisms and not true clusters. The most important aspect of using the…
UVIT study of UV bright stars in the globular cluster NGC 4147
Pradhan, Ananta C.; Mohapatra, Abhisek; Kumar, Ranjan +4 more
We present far ultraviolet (FUV) observations of globular cluster NGC 4147 using three FUV filters, BaF
Photometric and kinematical analysis of Koposov 12 and Koposov 43 open clusters
Elsanhoury, W. H.
We present a photometric and kinematical analysis of two poorly studied open clusters, Koposov 12 (FSR 802) and Koposov 43 (FSR 848), by using cross-matched data from PPMXL and Gaia DR2 catalogs. We used astrometric parameters to identify 285 and 310 cluster members for Koposov 12 and Koposov 43, respectively. Using the extracted member candidates…
Science with the AstroSat Soft X-ray telescope: An overview
Dewangan, Gulab C.; Singh, Kulinder Pal; Bhattacharyya, Sudip +6 more
The Soft X-ray Telescope (SXT) aboard the AstroSat satellite is the first Indian X-ray telescope in space. It is a modest size X-ray telescope with a charge coupled device (CCD) camera in the focal plane, which provides X-ray images in the
AstroSat view of the NLS1 galaxy Mrk 335
Dewangan, Gulab C.; Misra, Ranjeev; Ezhikode, Savithri H.
We present the results from the multi-wavelength monitoring observations of the Narrow-Line Seyfert 1 galaxy Mrk 335 with AstroSat. We analysed both the X-ray (SXT and LAXPC) and UV (UVIT) data of the source at two epochs, separated by
Exploring sub-MeV sensitivity of AstroSat–CZTI for ON-axis bright sources
Rao, A. R.; Bhalerao, Varun; Mithun, N. P. S. +5 more
The Cadmium–Zinc–Telluride Imager (CZTI) onboard AstroSat is designed for hard X-ray imaging and spectroscopy in the energy range of 20–100 keV. The CZT detectors are of 5-mm thickness and hence have good efficiency for Compton interactions beyond 100 keV. The polarisation analysis using CZTI relies on such Compton events and have been verified ex…
On the unified view of extragalactic sources based on their broadband emission properties
Iyida, E. U.; Eya, I. O.; Odo, F. C.
Our understanding of the unification of jetted active galactic nuclei (AGNs) has advanced greatly as the size of extragalactic sources increased. In this paper, based on the large sample of radio sources, we compiled 680 blazars (279 flat spectrum radio quasars (FSRQs) and 401 BL Lacertae (BL Lacs)) from the 3FGL sample and 64 Seyfert galaxies (3 …