visit 'Publications' page for recent updates
More things are coming up soon...
More things are coming up soon...
The UV background
We have new UV background models that are consistent with measurements of hydrogen and helium photoionization rates across all redshifts, and constraints on Hydrogen ans Helium reionization. Redshift evolution of our fiducial model is shown on the right. We also provide 6 additional models that are obtained with different quasar spectral shape, one of the uncertain parameters of the UV background. All these models are included in the latest version of the photoionization code CLOUDY. Also our models extend from far IR till TeV gamma-rays. Ref: Khaire & Srianand 2019 MNRASMNRAS, 484, 4174 |
Star Formation History and Dust Attenuation We present a novel method which lifts the degeneracy between star formation rate density and dust attenuation for an assumed extinction curve. We show that the Large Magellanic cloud supershell extinction curve gives consistent results with various observations.
Ref: Khaire & Srianand, 2015, ApJ, 850, 33 [ADS][arXiv] |
Extragalactic Background LightWe estimate the intensity of Extragalactic Background Light (EBL) up to z~8 from ultraviolet to infrared wavelengths. The collision of these photons with the high energy gamma rays destroys themselves through electron positron pair production. We calculate the optical depth encountered by such gamma rays and compare it with the recent measurements from Fermi Large Area Telescope.
Ref: Khaire & Srianand, 2015, ApJ, 850, 33 [ADS] [arXiv] |
Effect of H I ionizing photons from galaxies on the inferred He IIWe show that the inferred He II gas distribution in the IGM depends strongly on the assumed values of H I ionizing photons emitted by galaxies. This effect changes the mean free path and the intensity of the He II ionizing photons. We show that the increasing He II Lyman alpha effective optical depths observed at z>2.5 can be explained using this radiative transfer effect.
Ref: Khaire & Srianand, MNRAS, 431, L53, [ADS] [arXiv] |