A5035882535- Galaxies: Formation, Evolution, Phenomena
- Cosmology and Gravitation Theories
- Astronomy and Astrophysical Research
- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Radio Astronomy Observations and Technology
- Calibration and Measurement Techniques
- Geophysics and Gravity Measurements
- Scientific Research and Discoveries
- Gamma-ray bursts and supernovae
UNSW Sydney
2018-2019
Ioffe Institute
2015-2016
Peter the Great St. Petersburg Polytechnic University
2015-2016
Russian Academy of Sciences
2015
We report a new detection of neutral deuterium in the sub Damped Lyman Alpha system with low metallicity [O/H]\,=\,$-2.042 \pm 0.005$ at $z_{\rm abs}=2.437$ towards QSO~J\,1444$+$2919. The hydrogen column density this is log$N$(H\,{\sc i})~$=19.983\pm0.010$ and measured value abundance log(D/H)~$=-4.706\pm0.007_{\rm stat}\pm0.067_{\rm syst}$. This meets set strict selection criteria stated recently by Cooke et al. and, therefore, widens {\it Precision Sample} D/H. However, possible...
The spectrum of the zem = 2.63 quasar Q1009+2956 has been observed extensively on Keck telescope. Lyman limit absorption system zabs 2.504 was previously used to measure D/H by Burles & Tytler using a with signal noise (S/N) approximately 60 per pixel in continuum near Ly α at 2.504. larger data set now available combines form an exceptionally high S/N spectrum, around 147 pixel. Several heavy element lines are detected this system, providing strong constraints kinematic structure. We...
The zabs = 2.504 Lyman Limit absorption system (LLS) towards Q1009+2956 has previously been used to estimate the primordial deuterium abundance. Since initial measurement by Burles & Tytler [1], this quasar observed extensively with Keck telescope, providing a substantial increase in signal-to-noise (from 60 147 at continuum level of Ly-α 2.504). We explore set different models for and find that feature is contaminated from low column density HI cloud. This significantly limits precision...
The Cosmological Principle, the combined assumptions of cosmological isotropy and homogeneity, underpins standard model Big Bang cosmology with which we interpret astronomical observations. A new test over redshift range $2<z<4$ across large angular scales on sky is presented. We use distribution neutral hydrogen, as probed by Ly$\alpha$ forest seen towards distant quasars. Sloan Digital Sky Survey provides largest dataset quasar spectra available to date. information from Data Releases 12...
An influence of annihilation and decay the dark matter particles on baryon-to-photon ratio has been studied for different cosmological epochs. We consider parameter values such as mass, cross section, lifetime so on. The obtained results are compared with data which come from Big Bang nucleosynthesis calculation analysis anisotropy cosmic microwave background radiation. It shown that modern value density ΩCDM = 0.26 is enough to provide variation up Δη/η ∼ 0.01÷1 particles, but it also leads...
Modifications were made to the Sloan Digital Sky Survey’s Baryonic Oscillations Spectroscopic Survey (SDSS/BOSS) optical fibres assigned quasar targets in order improve signal-to-noise ratio Ly- α forest. However, consequence of these modifications is that quasars observed this way require additional flux correction procedures recover correct spectral shapes. In paper we describe such a procedure, based on geometry problem, and other observational parameters. Applying several methods four...