80 citations · 470 across the 19 of their papers we have counts for
19 papers
Systematic effects on a Compton polarimeter at the focus of an X-ray mirror
M. Aoyagi, R. G. Bose, S. Chun +23
XL-Calibur is a balloon-borne Compton polarimeter for X-rays in the 15-80 keV range. Using an X-ray mirror with a 12 m focal length for collecting photons onto a beryllium sc…
The design and performance of the XL-Calibur anticoincidence shield
N. K. Iyer, M. Kiss, M. Pearce +31
The XL-Calibur balloon-borne hard X-ray polarimetry mission comprises a Compton-scattering polarimeter placed at the focal point of an X-ray mirror. The polarimeter is housed withi…
Peculiar temporal and spectral features in highly obscured HMXB pulsar IGR J16320-4751 using XMM-Newton
Varun, Nirmal Iyer, Biswajit Paul
IGR J16320-4751 is a highly obscured HMXB source containing a very slow neutron star ( sec) orbiting its supergiant companion star with a period of 9 days.…
Performance of the X-Calibur Hard X-Ray Polarimetry Mission during its 2018/19 Long-Duration Balloon Flight
Quincy Abarr, Banafsheh Beheshtipour, Matthias Beilicke +28
X-Calibur is a balloon-borne telescope that measures the polarization of high-energy X-rays in the 15--50keV energy range. The instrument makes use of the fact that X-rays scatter…
Evolution of timing and spectral characteristics of 4U 1901+03 during its 2019 outburst using the Swift and NuSTAR observatories
Aru Beri, Tinku, Nirmal K. Iyer +1
We report the results from a detailed timing and spectral study of transient X-ray pulsars, 4U 1901+03 during its 2019 outburst. We performed broadband spectroscopy in the 1-70 keV…
XL-Calibur -- a second-generation balloon-borne hard X-ray polarimetry mission
Q. Abarr, H. Awaki, M. G. Baring +38
XL-Calibur is a hard X-ray (15-80 keV) polarimetry mission operating from a stabilised balloon-borne platform in the stratosphere. It builds on heritage from the X-Calibur mission,…
Observations of a GX 301-2 Apastron Flare with the X-Calibur Hard X-Ray Polarimeter Supported by NICER, the Swift XRT and BAT, and Fermi GBM
Q. Abarr, M. Baring, B. Beheshtipour +28
The accretion-powered X-ray pulsar GX 301-2 was observed with the balloon-borne X-Calibur hard X-ray polarimeter during late December 2018, with contiguous observations by the NICE…
A Compton polarimeter using scintillators read out with MPPCs through Citiroc ASIC
Rakhee Kushwah, Nirmal K. Iyer, Mózsi Kiss +2
In recent years, a number of purpose-built scintillator-based polarimeters have studied bright astronomical sources for the first time in the hard X-ray band (tens to hundreds of k…
AstroSat view of MAXI J1535-571: broadband spectro-temporal features
Sreehari H., Ravishankar B. T., Nirmal Iyer +4
We present the results of Target of Opportunity (ToO) observations made with AstroSat of the newly discovered black hole binary MAXI J1535-571. We detect prominent C-type Quasi-per…
LAXPC / AstroSat Study of ~ 1 and ~ 2 mHz Quasi-periodic Oscillations in the Be/X-ray Binary 4U 0115+63 During its 2015 Outburst
Jayashree Roy, P. C. Agrawal, N. K. Iyer +13
The Be X-ray Binary 4U 0115+63 was observed by Large Area X-ray Proportional Counter (LAXPC) instrument on AstroSat on 2015 October 24 during the peak of a giant Type II outburst.…
Gamma-ray burst localisation strategies for the SPHiNX hard X-ray polarimeter
L. Heckmann, N. K. Iyer, M. Kiss +2
SPHiNX is a proposed gamma-ray burst (GRB) polarimeter mission operating in the energy range 50-600 keV with the aim of studying the prompt emission phase. The polarisation sensiti…
Constraining the mass of the black hole GX 339-4 using spectro-temporal analysis of multiple outbursts
Sreehari H., Nirmal Iyer, Radhika D. +2
We carried out spectro-temporal analysis of the archived data from multiple outbursts spanning over the last two decades from the black hole X-ray binary GX 339-4. In this paper, t…
Broad-band spectral evolution and temporal variability of IGR J17091-3624 during its 2016 outburst : SWIFT and NuSTAR results
Radhika D., H. Sreehari, A. Nandi +2
We report on the 2016 outburst of the transient Galactic Black Hole candidate IGR J17091-3624 based on the observation campaign carried out with SWIFT and NuSTAR. The outburst prof…
Accretion Flow Dynamics During 1999 Outburst of XTE J1859+226 - Modeling of Broadband Spectra and Constraining the Source Mass
A. Nandi, S. Mandal, H. Sreehari +6
We examine the dynamical behavior of accretion flow around XTE J1859+226 during the 1999 outburst by analyzing the entire outburst data ( 166 days) from RXTE Satellite. Towar…
Observational aspects of Outbursting Black Hole Sources - Evolution of Spectro-Temporal features and X-ray Variability
H. Sreehari, Anuj Nandi, D. Radhika +2
We report on our attempt to understand the outbursting profile of Galactic Black Hole (GBH) sources, keeping in mind the evolution of temporal and spectral features during the outb…
Orbital variations in intensity and spectral properties of the highly obscured sgHMXB IGR J16318-4848
Nirmal Iyer, Biswajit Paul
IGR J16318-4848 is an X-ray binary with the highest known line of sight absorption column density among all known X-ray binary systems in our galaxy. In order to investigate the re…
Variations in the Cyclotron Resonant Scattering Features during 2011 outburst of 4U 0115+63
N. Iyer, D. Mukherjee, G. C. Dewangan +2
We study the variations in the Cyclotron Resonant Scattering Feature (CRSF) during 2011 outburst of the high mass X-ray binary 4U 0115+63 using observations performed with Suzaku,…
Determination of mass of IGR J17091-3624 from "Spectro-Temporal" variations during onset-phase of the 2011 outburst
N. Iyer, A. Nandi, S. Mandal
The 2011 outburst of the black hole candidate IGR J17091-3624 followed the canonical track of state transitions along with the evolution of Quasi-Periodic Oscillation (QPO) frequen…
Spectro-temporal evolution during the onset-phase of the 2011 outburst of IGR J17091-3624. Implications on accretion disk dynamics
Nirmal Iyer, A. Nandi
We re-analysed the archival data of RXTE / INTEGRAL / Swift satellites at the onset phase of the 2011 outburst of the X-ray source IGR J17091-3624. The evolution of the spectral an…