English
Related papers

Related papers: Re-visiting the bounds on hydrogen-antihydrogen os…

200 papers

We derive constraints on the thermal and ionization states of the intergalactic medium (IGM) at redshift $\approx$ 9.1 using new upper limits on the 21-cm power spectrum measured by the LOFAR radio-telescope and a prior on the ionized…

Modern radio interferometers sensitive to low frequencies will make use of wide-band detectors. For such wide bandwidths, dispersive atmospheric effects introduce variations in the fringe delay which change through the band of the…

Instrumentation and Methods for Astrophysics · Physics 2011-01-25 I. Marti-Vidal

A new method is proposed to measure the Hubble constant H0 through the mean transmitted flux observed from high redshift quasars. A semi-analytical model for the cosmological-independent volume density distribution function is adopted which…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 V. C. Busti , R. N. Guimarães , J. A. S. Lima

Power spectral density measurements of any sampled signal are typically restricted by both acquisition rate and frequency response limitations of instruments, which can be particularly prohibitive for video-based measurements. We have…

Biological Physics · Physics 2009-02-10 Wesley Philip Wong , Ken Halvorsen

Multiband sensing is a promising technology that utilizes multiple non-contiguous frequency bands to achieve high-resolution target sensing. In this paper, we investigate the fundamental limits and optimization of multiband sensing,…

Signal Processing · Electrical Eng. & Systems 2023-02-01 Yubo Wan , An Liu , Rui Du , Tony Xiao Han

Hydrodynamic simulations predict that a significant fraction of the gas in the current Universe is in the form of high temperature, highly ionized plasma emitting and absorbing primarily in the soft X-ray and UV bands, dubbed the Warm-Hot…

Cosmology and Nongalactic Astrophysics · Physics 2010-08-31 Eugenio Ursino , Massimiliano Galeazzi , Mauro Roncarelli

The Galactic interstellar turbulence affects the density distribution and star formation. We introduce a new method of measuring interstellar turbulent density spectra by using the dispersion measures (DMs) of a large sample of pulsars.…

Astrophysics of Galaxies · Physics 2021-01-06 Siyao Xu , Bing Zhang

The gases of the interstellar medium (ISM) possess orders of magnitude more mass than those of all the stars combined and are thus the prime component of the baryonic universe. With L-band surface sensitivity even better than the planned…

Instrumentation and Methods for Astrophysics · Physics 2019-04-05 Carl Heiles , Di Li , Naomi McClure-Griffiths , Lei Qian , Shu Liu

Recent claims of a gamma-ray excess in the diffuse galactic emission detected by the Fermi Large Area Telescope with a morphology similar to the WMAP haze were based on the assumption that spatial templates of the interstellar medium (ISM)…

Astrophysics of Galaxies · Physics 2010-04-16 Tim Linden , Stefano Profumo

Mapping the intergalactic medium (IGM) in Lyman-$\alpha$ emission would yield unprecedented tomographic information on the large-scale distribution of baryons and potentially provide new constraints on the UV background and various feedback…

Astrophysics of Galaxies · Physics 2021-06-22 Joris Witstok , Ewald Puchwein , Girish Kulkarni , Renske Smit , Martin G. Haehnelt

Feedback from massive stars is one of the least understood aspects of galaxy formation. We perform a suite of vertically stratified local interstellar medium (ISM) simulations in which supernova rates and vertical gas column densities are…

Astrophysics · Physics 2009-09-24 M. Ryan Joung , Mordecai-Mark Mac Low , Greg L. Bryan

We model the complex distribution of atomic hydrogen (HI) in the interstellar medium (ISM) assuming that it is driven entirely by supernovae (SN). We develop and assess two different models. In the first approach, the simulated volume is…

Astrophysics · Physics 2009-11-11 Jacqueline A. Hodge , Avinash A. Deshpande

Gas cooling processes in the interstellar medium (ISM) are key to understanding how star-formation processes occur in galaxies. Far-infrared (FIR) fine-structure emission lines can be used as a tool to understand the gas conditions and…

Astrophysics of Galaxies · Physics 2023-12-06 Andrés Felipe Ramos Padilla , Lingyu Wang , F. F. S. van der Tak , Scott Trager

Intermediate degree modes of the solar oscillations have previously been used to determine the solar helium abundance to a high degree of precision. However, we cannot expect to observe such modes in other stars. In this work we investigate…

Astrophysics · Physics 2009-11-10 Sarbani Basu , Anwesh Mazumdar , H. M Antia , Pierre Demarque

We present new measurements of the thermal state of the intergalactic medium (IGM) at $z\sim2.4$ derived from absorption line profiles in the Ly$\alpha$ forest. We use a large set of high-resolution hydrodynamical simulations to calibrate…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 James S. Bolton , George D. Becker , Martin G. Haehnelt , Matteo Viel

A pulsar's pulse profile gets broadened at low frequencies due to dispersion along the line of sight or due to multi-path propagation. The dynamic nature of the interstellar medium makes both of these effects time-dependent and introduces…

We study information theoretic limits of recovering an unknown $n$ dimensional, complex signal vector $\mathbf{x}_\star$ with unit norm from $m$ magnitude-only measurements of the form $y_i = |(\mathbf{A} \mathbf{x}_\star)_i|^2, \; i = 1,2…

Statistics Theory · Mathematics 2020-08-05 Rishabh Dudeja , Junjie Ma , Arian Maleki

The third flight of the Medium Scale Anisotropy Measurement (MSAM1), in June 1995, observed a new strip of sky, doubling the sky coverage of the original MSAM1 dataset. MSAM1 observes with a 0.5 deg beam size in four bands from 5-20 icm.…

X-ray observations of the hot gas filling the intra-cluster medium provide a wealth of information on the dynamics of clusters of galaxies. The global equilibrium of the ICM is believed to be partially ensured by non-thermal pressure…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-25 E. Cucchetti , N. Clerc , E. Pointecouteau , P. Peille , F. Pajot

The radio frequency 1.4 GHz transition of the atomic hydrogen is one of the important tracers of the diffuse neutral interstellar medium. Radio astronomical observations of this transition, using either a single dish telescope or an array…

Astrophysics of Galaxies · Physics 2016-08-29 Nirupam Roy