34 citations · 81 across the 14 of their papers we have counts for
15 papers
First Detection of Radio Polarization During Jet Formation in the Changing-Look AGN 1ES 1927+654
Onic I. Shuvo, Eileen T. Meyer, Sibasish Laha +10
We present a multiwavelength radio study of the changing-look AGN 1ES 1927+654 following its renewed X-ray brightening since mid-2022, combining VLBA imaging with multi-band and ti…
Reconnection-driven State Transitions in Flat Spectrum Radio Quasars
Agniva Roychowdhury
We extend the work of Roychowdhury (2026) on skewness variations of the logarithmic flux, driven by large GeV flares in FSRQs, to a sample of 18 FSRQs. We find that they can be cat…
Parameter Estimation Limits in Blazars
Agniva Roychowdhury
Parameter degeneracy in blazar spectral energy distributions (SEDs) is known but rarely quantified. This paper introduces a Fisher Information approach to determine theoretical lim…
An Afterglow Study of the "New Year's Burst" GRB 220101A
Agniva Roychowdhury, Tuomas Kangas, Andrew Fruchter +12
We present a detailed broadband afterglow study of GRB 220101A ( s) combining multi-wavelength data from soft X-rays until 6 GHz. The afterglow light cu…
Minijets and Broken Stationarity in a Blazar : Novel Insights into the Origin of -ray Variability in CTA 102
Agniva Roychowdhury
High-energy blazar light curves, in X-rays and beyond, have historically preferred a log-normal flux distribution, signifying multiplicative processes either in the jet itself or d…
Late-time radio brightening and emergence of a radio jet in the changing-look AGN 1ES 1927+654
Eileen T. Meyer, Sibasish Laha, Onic I. Shuvo +32
We present multi-frequency (5-345 GHz) and multi-resolution radio observations of 1ES 1927+654, widely considered one of the most unusual and extreme changing-look active galactic…
A re-emerging bright soft-X-ray state of the changing-look Active Galactic Nucleus 1ES~1927+654: a multi-wavelength view
Ritesh Ghosh, Sibasish Laha, Eileen Meyer +24
1ES1927+654 is a nearby active galactic nucleus that has shown an enigmatic outburst in optical/UV followed by X-rays, exhibiting strange variability patterns at timescales of mont…
Proper Motions in the sub-kiloparsec Jet of 3C 78: Novel Constraints on the Physical Nature of Relativistic Jets
Agniva Roychowdhury, Eileen T. Meyer, Markos Georganopoulos +1
Jets from active galactic nuclei are thought to play a role in the evolution of their host and local environments, but a detailed prescription is limited by the understanding of th…
A new generation DIFMAP for Modelfitting Interferometric Data and Estimating Variances, Biases and Correlations
Agniva Roychowdhury, Eileen T. Meyer
We present the program `Catalogue of proper motions in extragalactic jets from Active galactic Nuclei with Very large Array Studies' or CAgNVAS, with the objective of using archiva…
A Multi-Wavelength Study of Multiple Spectral Component Jets in AGN: Testing the IC/CMB Model for the Large-Scale-Jet X-ray Emission
Peter Breiding, Eileen T. Meyer, Markos Georganopoulos +3
Over 150 resolved, kpc-scale X-ray jets hosted by active galactic nuclei have been discovered with the Chandra X-ray Observatory. A significant fraction of these jets have an X-ray…
A radio, optical, UV and X-ray view of the enigmatic changing look Active Galactic Nucleus 1ES~1927+654 from its pre- to post-flare states
Sibasish Laha, Eileen Meyer, Agniva Roychowdhury +17
The nearby type-II AGN 1ES1927+654 went through a violent changing-look (CL) event beginning December 2017 during which the optical and UV fluxes increased by four magnitudes over…
Circumnuclear Dust in AP Librae and the source of its VHE emission
Agniva Roychowdhury, Eileen T. Meyer, Markos Georganopoulos +2
The broad high-energy spectral component in blazars is usually attributed to various inverse Compton scattering processes in the relativistic jet, but has not been clearly identifi…
Exploring the Voids: Luminosity Functions and Magnetic Field
Agniva Roychowdhury, Saumyadip Samui
We present semi-analytical models for magnetisation of the void inter-galactic medium (IGM) by outflows from void galaxies. The number density of dark matter haloes in an under-den…
Time-rescaling of Dirac dynamics: shortcuts to adiabaticity in ion traps and Weyl semimetals
Agniva Roychowdhury, Sebastian Deffner
Only very recently, rescaling time has been recognized as a way to achieve adiabatic dynamics in fast processes. The advantage of time-rescaling over other shortcuts to adiabaticit…
Possible Accretion Disk Origin of the Emission Variability of a Blazar Jet
Ritaban Chatterjee, Agniva Roychowdhury, Sunil Chandra +1
We analyze X-ray light curves of the blazar Mrk 421 obtained from the Soft X-ray Imaging Telescope and the Large Area X-Ray Proportional Counter instrument onboard the Indian space…