156 citations · 851 across the 36 of their papers we have counts for
17 papers · 1 filter
Non-Primordial Contribution to the Cosmic Microwave Background
Akshith Asundi, Vikram Khaire
The cosmic microwave background is interpreted as relic thermal radiation from the epoch of recombination at z~1090. Recent work by Gjergo & Kroupa (GK25) have challenged this assu…
A Measurement of the Thermal and Ionization State of the IGM at
Teng Hu, Vikram Khaire, Joseph F. Hennawi +4
We apply a machine-learning-based inference method that exploits the joint Doppler parameter-column density (b-NHI) distribution from Lya forest decomposition to measure the therma…
FLAME: Fitting Ly Absorption lines using Machine learning
Priyanka Jalan, Vikram Khaire, M. Vivek +1
We introduce FLAME, a machine-learning algorithm designed to fit Voigt profiles to HI Lyman-alpha (Ly) absorption lines using deep convolutional neural networks. FLAME integrate…
Measurements of the Thermal and Ionization State of the Intergalactic Medium during the Cosmic Afternoon
Teng Hu, Vikram Khaire, Joseph F. Hennawi +4
We perform the first measurement of the thermal and ionization state of the intergalactic medium (IGM) across 0.9 < z < 1.5 using 301 \lya absorption lines fitted from 12 HST STIS…
The Impact of the WHIM on the IGM Thermal State Determined from the Low- Lyman- Forest
Teng Hu, Vikram Khaire, Joseph F. Hennawi +4
At , shock heating caused by large-scale velocity flows and possibly violent feedback from galaxy formation, converts a significant fraction of the cool gas ($T\sim 1…
Can the Low Redshift Lyman Alpha Forest Constrain AGN Feedback Models?
Vikram Khaire, Teng Hu, Joseph F. Hennawi +2
We investigate the potential of low-redshift Lyman alpha (Ly) forest for constraining active galactic nuclei (AGN) feedback models by analyzing the Illustris and IllustrisTNG si…
Measuring the thermal and ionization state of the low- IGM using likelihood free inference
Teng Hu, Vikram Khaire, Joseph F. Hennawi +6
We present a new approach to measure the power-law temperature density relationship and the UV background photoionization rate of the IGM base…
Effect of non-equilibrium ionization on derived physical conditions of the high- intergalactic medium
Prakash Gaikwad, Raghunathan Srianand, Vikram Khaire +1
Non-equilibrium ionization effects are important in cosmological hydrodynamical simulations but are computationally expensive. We study the effect of non-equilibrium ionization evo…
The Power Spectrum of the Lyman- Forest at z < 0.5
Vikram Khaire, Michael Walther, Joseph F. Hennawi +6
We present new measurements of the flux power-spectrum P(k) of the HI Lyman- forest spanning scales k ~ 0.001-0.1 s/km. These results were derived from 65 far ultraviole…
Detection of Low Metallicity Warm Plasma in a Galaxy Overdensity Environment at z ~ 0.2
Anand Narayanan, Blair D. Savage, Preetish K. Mishra +3
We present results from the analysis of a multiphase O VI - broad Ly-alpha absorber at z = 0.19236 in the HST/COS spectrum of PG 1121+422. The low and intermediate ionization metal…
Efficient adiabatic hydrodynamical simulations of the high-redshift intergalactic medium
Prakash Gaikwad, Tirthankar Roy Choudhury, Raghunathan Srianand +1
We present a post-processing tool for GADGET-2 adiabatic simulations to model various observed properties of the Ly forest at that enables an efficient param…
VoIgt profile Parameter Estimation Routine (VIPER): H I photoionization rate at z<0.5
Prakash Gaikwad, Raghunathan Srianand, Tirthankar Roy Choudhury +1
We have developed a parallel code called "VoIgt profile Parameter Estimation Routine (VIPER)" for automatically fitting the H I Ly- forest seen in the spectra of QSOs. We obtain…
Intergalactic Lyman continuum photon budget in the past 5 billion years
Prakash Gaikwad, Vikram Khaire, Tirthankar Roy Choudhury +1
We constrain the H I photoionization rate at by comparing the flux probability distribution function and power spectrum of the Ly- forest data a…
A Pair of O VI and Broad Ly-alpha Absorbers Probing Warm Gas in a Galaxy Group Environment at z ~ 0.4
Sachin Pachat, Anand Narayanan, Sowgat Muzahid +4
We report on the detection of two O VI absorbers separated in velocity by 710 km/s at z ~ 0.4 towards the background quasar SBS0957+599. Both absorbers are multiphase systems traci…
The redshift evolution of escape fraction of hydrogen ionizing photons from galaxies
Vikram Khaire, Raghunathan Srianand, Tirthankar Roy Choudhury +1
Using our cosmological radiative transfer code, we study the implications of the updated QSO emissivity and star formation history for the escape fraction (f_esc) of hydrogen ioniz…
Photon underproduction crisis: Are QSOs sufficient to resolve it?
Vikram Khaire, Raghunathan Srianand
We investigate the recent claim of 'photon underproduction crisis' by Kollmeier et al. (2014) which suggests that the known sources of ultra-violet (UV) radiation may not be suffic…
He II optical depth and UV escape fraction of galaxies
Vikram Khaire, Raghunathan Srianand
We study the effect of H I ionizing photons escaping from high-redshift (high-z) galaxies have on the He II ionizing ultraviolet background (UVB) radiation. While these photons do…