101 citations · 773 across the 20 of their papers we have counts for
17 papers · 1 filter
Strong Lensing Tomography: Double and pseudo multi-source plane strong gravitational lensing to constrain dark energy
Paras Sharma, Simon Birrer, Narayan Khadka +12
Tomographic measurements of gravitational lensing with different lens and source redshift distributions contain crucial information about the universe's relative expansion rate, an…
SLSim: a strong lensing population simulation package
Narayan Khadka, Simon Birrer, Henry Best +45
Gravitational lensing offers unique insights into cosmology by bending light around massive objects. Strong gravitational lensing, in particular, produces magnified and often multi…
Investigating the Dark Energy Constraint from Strongly Lensed AGN at LSST-Scale
Sydney Erickson, Martin Millon, Padmavathi Venkatraman +12
Strongly lensed Active Galactic Nuclei (AGN) with an observable time delay can be used to constrain the expansion history of the Universe through time-delay cosmography (TDC). As t…
Breaking the mass-sheet degeneracy in strong lensing mass modeling with weak lensing observations
Narayan Khadka, Simon Birrer, Alexie Leauthaud +1
The Hubble constant (), a crucial parameter in cosmology, quantifies the expansion rate of the universe so its precise measurement is important to understand the fundamental d…
Quasar UV/X-ray relation luminosity distances are shorter than reverberation-measured radius-luminosity relation luminosity distances
Narayan Khadka, Michal Zajaček, Raj Prince +5
We use measurements of 59/58 quasars (QSOs), over a redshift range , to do a comparative study of the radius--luminosity () and X-rayUV luminosity…
Consistency study of high- and low-accreting Mg ii quasars: No significant effect of the Fe ii to Mg ii flux ratio on the radius-luminosity relation dispersion
Narayan Khadka, Michal Zajaček, Swayamtrupta Panda +2
We use observations of 66 reverberation-measured \Mgii\ quasars (QSOs) in the redshift range -- a subset of the 78 QSOs we previously studied that also hav…
Using quasar and gamma-ray burst measurements to constrain cosmological dark energy models
Narayan Khadka
Observational evidence for the accelerated expansion of the universe requires dark energy for its explanation if general relativity is an accurate model of gravity. However, dark e…
Do reverberation-measured H quasars provide a useful test of cosmology?
Narayan Khadka, Mary Loli Martínez-Aldama, Michal Zajaček +2
We use 118 H quasar (QSO) observations in the redshift range to simultaneously constrain cosmological model parameters and QSO 2-parameter radius-lumin…
Standardizing Dainotti-correlated gamma-ray bursts, and using them with standardized Amati-correlated gamma-ray bursts to constrain cosmological model parameters
Shulei Cao, Narayan Khadka, Bharat Ratra
We show that each of the three Dainotti-correlated gamma-ray burst (GRB) data sets recently compiled by Wang et al. and Hu et al., that together probe the redshift range $0.35 \leq…
Do quasar X-ray and UV flux measurements provide a useful test of cosmological models?
Narayan Khadka, Bharat Ratra
The recent compilation of quasar (QSO) X-ray and UV flux measurements include QSOs that appear to not be standardizable via the X-ray luminosity and UV luminosity () re…
Standardizing reverberation-measured Mg II time-lag quasars, by using the radius-luminosity relation, and constraining cosmological model parameters
Narayan Khadka, Zhefu Yu, Michal Zajaček +3
We use 78 reverberation-measured Mg II time-lag quasars (QSOs) in the redshift range to constrain cosmological parameters in six different cosmological mo…
Do gamma-ray burst measurements provide a useful test of cosmological models?
Narayan Khadka, Orlando Luongo, Marco Muccino +1
We study eight different gamma-ray burst (GRB) data sets to examine whether current GRB measurements -- that probe a largely unexplored part of cosmological redshift () space --…
Determining the range of validity of quasar X-ray and UV flux measurements for constraining cosmological model parameters
Narayan Khadka, Bharat Ratra
We use six different cosmological models to study the recently-released compilation of X-ray and UV flux measurements of 2038 quasars (QSOs) which span the redshift range $0.009 \l…
Cosmological constraints from higher-redshift gamma-ray burst, HII starburst galaxy, and quasar (and other) data
Shulei Cao, Joseph Ryan, Narayan Khadka +1
We use higher-redshift gamma-ray burst (GRB), HII starburst galaxy (HIIG), and quasar angular size (QSO-AS) measurements to constrain six spatially flat and non-flat cosmological m…
Constraints on cosmological parameters from gamma-ray burst peak photon energy and bolometric fluence measurements and other data
Narayan Khadka, Bharat Ratra
We use measurements of the peak photon energy and bolometric fluence of 119 gamma-ray bursts (GRBs) extending over the redshift range of to simultaneously…
Using quasar X-ray and UV flux measurements to constrain cosmological model parameters
Narayan Khadka, Bharat Ratra
Risaliti and Lusso have compiled X-ray and UV flux measurements of 1598 quasars (QSOs) in the redshift range , part of which, , is large…
Quasar X-ray and UV flux, baryon acoustic oscillation, and Hubble parameter measurement constraints on cosmological model parameters
Narayan Khadka, Bharat Ratra
We use the Risaliti & Lusso (2015) compilation of 808 X-ray and UV flux measurements of quasars (QSOs) in the redshift range , alone and in conjuction with…