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The Absorption Measure Distribution (AMD) in the X-ray outflows of Seyfert active galactic nuclei (AGN) describes the distribution of absorbing column density as a function of ionization parameter. Up to now, AMD has been measured only for…

星系天体物理 · 物理学 2019-08-21 T. P. Adhikari , A. Różańska , K. Hryniewicz , B. Czerny , E. Behar

The study and quantification of UV photon-induced desorption of frozen molecules furthers our understanding of the chemical evolution of cold interstellar regions. Nitric oxide (NO) is an important intermediate species in both gas-phase and…

星系天体物理 · 物理学 2017-10-05 R. Dupuy , G. Féraud , M. Bertin , X. Michaut , T. Putaud , P. Jeseck , L. Philippe , C. Romanzin , V. Baglin , R. Cimino , J. -H. Fillion

We report optical absorption imaging of ultracold neutral plasmas.Images are used to measure the ion absorption spectrum, which is Doppler-broadened. Through the spectral width, we monitor ion equilibration in the first 250ns after plasma…

原子物理 · 物理学 2009-11-10 C. E. Simien , Y. C. Chen , P. Gupta , S. Laha , Y. N. Martinez , P. G. Mickelson , S. B. Nagel , T. C. Killian

Context. The [CII] 158 {\mu}m far-infrared (FIR) fine-structure line is one of the most important cooling lines of the star-forming interstellar medium (ISM). High spectral resolution observations have shown complex structures in the line…

High signal-to-noise spectra toward background quasars are crucial for uncovering weak absorption in the circumgalactic medium (CGM) of intervening galaxies, such as the diagnostic lines of N V that provide insight to the ionization process…

CMOS detectors offer many advantages over CCDs for optical and UV astronomical applications, especially in space where high radiation tolerance is required. However, astronomical instruments are most often designed for low light-level…

We study the column densities of neutral atomic, molecular, and warm ionized Galactic gas through their continuous absorption of extragalactic X-ray spectra at |b| > 25 degrees. For N(H,21cm) < 5x10^20 cm^-2 there is an extremely tight…

天体物理学 · 物理学 2014-10-13 John S. Arabadjis , Joel N. Bregman

A nanometer-thin-cell (in the direction of laser beam propagation) has been elaborated with the thickness of the atomic vapor column varying smoothly in the range of $L = \unit[50-1500]{nm}$. The cell allows one to study the behavior of the…

原子物理 · 物理学 2016-04-20 A. Sargsyan , Y. Pashayan-Leroy , C. Leroy , D. Sarkisyan

We present a detailed analysis of a high resolution spectrum of the damped Ly$\alpha$ system at $z_{\rm abs}$~=~2.8112toward PKS~0528-250. The absorption redshift is slightly larger than the emission redshift of the quasar. We estimate the…

天体物理学 · 物理学 2007-05-23 R. Srianand , P. Petitjean

We demonstrate site-resolved imaging of individual fermionic lithium-6 atoms in a 2D optical lattice. To preserve the density distribution during fluorescence imaging, we simultaneously cool the atoms with 3D Raman sideband cooling. This…

The accurate determination of atom numbers is an ubiquitous problem in the field of ultracold atoms. For modest atom numbers, absolute calibration techniques are available, however, for large numbers and high densities, the available…

Photoabsorption of atomic oxygen in the energy region below the $\rm 1s^{-1}$ threshold in x-ray spectroscopy from {\it Chandra} and {\it XMM-Newton} is observed in a variety of x-ray binary spectra. Photoabsorption cross sections…

高能天体物理现象 · 物理学 2015-06-16 B. M. McLaughlin , C. P. Ballance , K. P. Bowen , D. J. Gardenghi , W. C. Stolte

The calculation of the molecular column density from molecular spectral (rotational or ro-vibrational) transition measurements is one of the most basic quantities derived from molecular spectroscopy. Starting from first principles where we…

天体物理仪器与方法 · 物理学 2017-04-10 Jeffrey G. Mangum , Yancy L. Shirley

The atom-by-atom characterization of quantum gases requires the development of novel measurement techniques. One particularly promising new technique demonstrated in recent experiments uses strong fluorescent laser scattering from neutral…

量子气体 · 物理学 2013-05-29 Martin Shotter

We report the optical imaging of a single atom with nanometer resolution using an adaptive optical alignment technique that is applicable to general optical microscopy. By decomposing the image of a single laser-cooled atom, we identify and…

原子物理 · 物理学 2016-09-21 J. D. Wong-Campos , K. G. Johnson , B. Neyenhuis , J. Mizrahi , C. Monroe

The $\lambda$ = 2.06 $\mu$m absorption band of CO$_2$ is widely used for the remote sensing of atmospheric carbon dioxide, making it relevant to many important top-down measurements of carbon flux. The forward models used in the retrieval…

原子物理 · 物理学 2020-06-09 Hélène Fleurbaey , Hongming Yi , Erin M. Adkins , Adam J. Fleisher , Joseph T. Hodges

Optical absorption imaging has become a common technique for detecting the density distribution of ultracold atoms. The defocus effect generally produces artificial spatial structures in the obtained images, which confuses our understanding…

原子物理 · 物理学 2019-03-27 Tianyou Gao , Dongfang Zhang , Lingran Kong , Ruizong Li , Kaijun Jiang

We calculate the neutral hydrogen column density of self-absorption in QSOs predicted in a model where the QSOs are located in the same halos that contain the gas in damped Lya absorption systems. The model is parameterized by the…

天体物理学 · 物理学 2009-09-25 S. M. Khairul Alam , Jordi Miralda-Escude

We present detailed photoionization models of well aligned optically thin C III absorption components at $2.1 < z < 3.4$. Using our models we estimate density ($n_{\rm \tiny H}$), metallicity ($[C/H]$), total hydrogen column density and…

星系天体物理 · 物理学 2019-01-23 Abhisek Mohapatra , R. Srianand , Vikram Khaire , Ananta C. Pradhan