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In this paper, we present the formalism of simulating Lyman-$\alpha$ emission and polarization around reionization ($z$ = 8) from a plane-parallel ionization front. We accomplish this by using a Monte Carlo method to simulate the production…

宇宙学与河外天体物理 · 物理学 2023-05-31 Yuanyuan Yang , Emily Koivu , Chenxiao Zeng , Heyang Long , Christopher M. Hirata

In this work, we present for the first time the Lyman $\alpha$ intensities measured by Voyager 1/UVS in 2003-2014 (at 90-130 AU from the Sun). During this period Voyager 1 measured the Lyman $\alpha$ emission in the outer heliosphere at an…

太阳与恒星天体物理 · 物理学 2017-10-20 O. A. Katushkina , E. Quemerais , V. V. Izmodenov , R. Lallement , B. R. Sandel

We present Markov Chain Monte Carlo radiative transfer modeling of a joint ALMA 345 GHz and spectral energy distribution dataset for a sample of 97 protostellar disks from the VLA and ALMA Nascent Disk and Multiplicity Survey of Orion…

太阳与恒星天体物理 · 物理学 2022-04-20 Patrick D. Sheehan , John J. Tobin , Leslie L. Looney , S. Thomas Megeath

We propose a new methodology for probing the cosmological variability of alpha from pairs of FeII lines (SIDAM, single ion differential alpha measurement) observed in individual exposures from a high resolution spectrograph. By this we…

天体物理学 · 物理学 2009-11-10 S. A. Levshakov , M. Centurion , P. Molaro , S. D'Odorico

In situ observations of interstellar neutral (ISN) helium atoms by the IBEX-Lo instrument onboard the Interstellar Boundary Explorer (IBEX) mission are used to determine the velocity and temperature of the pristine very local interstellar…

The conditions within the ionization front of a quasar during reionization (T ~ 30,000 K, neutral hydrogen fraction ~ 0.5) are ideal for producing Lyman-alpha emission via collisional excitation of hydrogen atoms. Observations of this…

宇宙学与河外天体物理 · 物理学 2017-02-15 Frederick B. Davies , Steven R. Furlanetto , Matthew McQuinn

We calibrate here cosmological radiative transfer simulation with ATON/RAMSES with a range of measurements of the Lyman alpha opacity from QSO absorption spectra. We find the Lyman alpha opacity to be very sensitive to the exact timing of…

宇宙学与河外天体物理 · 物理学 2018-05-23 Jonathan Chardin , Martin G. Haehnelt , Dominique Aubert , Ewald Puchwein

We study hydrogen plasmas at magnetic fields B ~ 10^{12}-10^{13} Gauss, densities ~ 10^{-3}-10^3 g/cc and temperatures T ~ 10^{5.5}-10^{6.5} K, typical of photospheres of middle-aged cooling neutron stars. We construct an analytical free…

等离子体物理 · 物理学 2009-10-31 A. Y. Potekhin , G. Chabrier , Yu. A. Shibanov , J. Ventura

The Voyagers (V) 1 and 2 Ultraviolet Spectrometers (UVS) data harvest covers outer planets encounters, heliosphere sky-background measurements, and stellar spectrophotometry. Because their operation period overlaps with many ultraviolet…

地球与行星天体物理 · 物理学 2016-04-12 Lotfi Ben-Jaffel , Jay B. Holberg

We compare observations of HI from the Very Large Array (VLA) and the Arecibo Observatory and observations of HCO$^+$ from the Atacama Large Millimeter/submillimeter Array (ALMA) and the Northern Extended Millimeter Array (NOEMA) in the…

Using the recently observed torsional Alfv\'en waves in solar prominences, we determine the ionisation state of the plasma by taking into account that Alfv\'en waves propagate in a partially ionised prominence plasma. We derive the…

太阳与恒星天体物理 · 物理学 2020-02-21 Istvan Ballai

We present a significantly updated CO$_2$ altitude profile for Venus (64.2-0.9 km) and provide support for a potential deep lower atmospheric haze of particles (17 km and lower). We extracted this information by developing a new analytical…

地球与行星天体物理 · 物理学 2022-12-14 Rakesh Mogul , Sanjay S. Limaye , Michael. J. Way

In this work is examined a new modeling way of describing the continuous absorption of electromagnetic (EM) radiation in a dense partially ionized hydrogen plasmas with electron densities about $5\cdot10^{18}$ cm$^{-3}$ -…

太阳与恒星天体物理 · 物理学 2018-03-14 A. A. Mihajlov , N. M. Sakan , V. A. Sreckovic , Y. Vitel

We continue our recent work to characterize the plasma content of high-redshift damped and sub-damped Lyman-alpha systems (DLAs/sub-DLAs), which represent multi-phase gaseous (proto)galactic disks and halos seen toward a background source.…

宇宙学与河外天体物理 · 物理学 2015-05-13 Andrew J. Fox , J. Xavier Prochaska , Cédric Ledoux , Patrick Petitjean , Arthur M. Wolfe , Raghunathan Srianand

When the neutral interstellar medium is exposed to EUV and soft X ray radiation, the argon atoms in it are far more susceptible to being ionized than the hydrogen atoms. We make use of this fact to determine the level of ionization in the…

星系天体物理 · 物理学 2013-01-29 Edward B. Jenkins

Absolute values of VUV-emission of a 2.45 GHz microwave-driven hydrogen discharge are reported. The measurements were performed with a robust and straightforward method based on a photodiode and optical filters. It was found that the…

等离子体物理 · 物理学 2015-10-09 J. Komppula , O. Tarvainen , T. Kalvas , H. Koivisto , R. Kronholm , J. Laulainen , P. Myllyperkiö

We present a new implicit numerical algorithm for the calculation of the time dependent non-Local Thermodynamic Equilibrium of a gas in an external radiation field that is accurate, fast and unconditionally stable for all spatial and…

天体物理学 · 物理学 2007-05-23 R. Wehrse , D. T. Wickramasinghe , Romeel Davé

Molecular hydrogen transitions in the sub-damped Lyman alpha absorber at redshift z = 2.69, toward the background quasar SDSS J123714.60+064759.5, were analyzed in order to search for a possible variation of the proton-to-electron mass…

宇宙学与河外天体物理 · 物理学 2015-09-30 M. Daprà , J. Bagdonaite , M. T. Murphy , W. Ubachs

This is the second paper in a series whose aim is to predict the power spectrum of intensity and polarized intensity from cosmic reionization fronts. After building the analytic models for intensity and polarized intensity calculations in…

宇宙学与河外天体物理 · 物理学 2023-05-31 Emily Koivu , Heyang Long , Yuanyuan Yang , Christopher M. Hirata

We study the physical conditions in DLAs, using a sample of 33 systems toward 26 QSOs acquired for a recently completed survey of H_2 by Ledoux et al. (2003). We use the column densities of H_2 in different rotational levels, together with…

天体物理学 · 物理学 2009-11-13 Raghunathan Srianand , Patrick Petitjean , Cedric Ledoux , Gary Ferland , Gargi Shaw
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