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相关论文: The Outer Disk of the Milky Way Seen in 21-cm Abso…

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Using H I absorption spectra taken from the recent surveys of 21-cm line and continuum emission in the Galactic plane, the distribution of cool atomic clouds in the outer disk of the Milky Way is revealed. The warp of the midplane is…

星系天体物理 · 物理学 2009-01-21 John M. Dickey

Using the Australian Square Kilometre Array Pathfinder to measure 21-cm absorption spectra toward continuum background sources, we study the cool phase of the neutral atomic gas in the far outer disk, and in the inner Galaxy near the end of…

The neutral hydrogen 21 cm line is an excellent tracer of the atomic interstellar medium in the cold and the warm phases. Combined 21 cm emission and absorption observations are very useful to study the properties of the gas over a wide…

We discuss physical conditions in Galactic neutral hydrogen based on deep, high velocity resolution interferometric HI 21 cm absorption spectroscopy towards 33 compact extra-galactic radio sources. The HI 21 cm optical depth spectra have…

星系天体物理 · 物理学 2014-07-30 Nirupam Roy , Nissim Kanekar , Jayaram N. Chengalur

By including the most recent observations of HI 21-cm absorption through near-by galactic disks, we confirm our previous assertion that there is an anti-correlation between the abundance of cool neutral atomic gas and impact parameter.…

星系天体物理 · 物理学 2020-04-01 S. J. Curran

ABSRACT:We show how to use 21-cm emission and absorption studies to estimate the heat inputs to the neutral gas in low pressure environments, such as in outer disks of spiral galaxies, in galactic halos or in intergalactic space. For a…

天体物理学 · 物理学 2009-10-22 Edvige Corbelli , Edwin E. Salpeter

We have carried out deep, high velocity resolution, interferometric Galactic HI 21 cm absorption spectroscopy towards 32 compact extra-galactic radio sources with the Giant Metrewave Radio Telescope (GMRT) and the Westerbork Synthesis Radio…

星系天体物理 · 物理学 2014-07-30 Nirupam Roy , Nissim Kanekar , Robert Braun , Jayaram N. Chengalur

We present a deep XMM-Newton observation of the Galactic halo emission in the direction of the blazar 1ES 1553+113. In order to extract the Galactic halo component from the diffuse soft X-ray emission spectrum, accurately modeling the…

星系天体物理 · 物理学 2020-07-23 Sanskriti Das , Smita Mathur , Anjali Gupta , Fabrizio Nicastro , Yair Krongold

There is mounting evidence for an extra-planar gas layer around the Milky Way disk, similar to the anomalous HI gas detected in a few other galaxies. As much as 10% of the gas may be in this phase. We analyze HI clouds located in the…

星系天体物理 · 物理学 2015-05-14 L. Dedes , P. W. M Kalberla

The diffuse high-energy gamma-ray emission of the Milky Way arises from interactions of cosmic-rays (CRs) with interstellar gas and radiation field in the Galaxy. The neutral hydrogen (H I) gas component is by far the most massive and…

高能天体物理现象 · 物理学 2019-08-13 Gudlaugur Johannesson , Igor Moskalenko , Seth Digel

We present a 21-cm emission-absorption study towards extragalactic sources in the Canadian Galactic Plane Survey (CGPS). We have analyzed HI spectra towards 437 sources with S > 150 mJy, giving us a source density of 0.6 sources per square…

天体物理学 · 物理学 2009-11-10 S. T. Strasser , A. R. Taylor

In this paper we study 21-cm absorption spectra and the corresponding emission spectra toward bright continuum sources in the test region (326deg< l < 333 deg) of the Southern Galactic Plane Survey. This survey combines the high resolution…

天体物理学 · 物理学 2009-11-07 John M. Dickey , N. M. McClure-Griffiths , B. M. Gaensler , A. J. Green

Aims: We derive the 3-D HI volume density distribution for the Galactic disk out to R = 60 kpc. Methods: Our analysis is based on parameters for the warp and rotation curve derived previously. The data are taken from the…

天体物理学 · 物理学 2015-05-13 P. M. W. Kalberla , L. Dedes

I review studies of the hot gaseous medium in and around nearby normal disk galaxies, including the Milky Way. This medium represents a reservoir of materials required for lasting star formation, a depository of galactic feedback (e.g.,…

天体物理学 · 物理学 2009-11-11 Q. Daniel Wang

We report high spectral resolution Australia Telescope Compact Array HI 21 cm observations resulting in the detection of the warm neutral medium (WNM) of the Galaxy in absorption against two extragalactic radio sources, PKS 1814-637 and PKS…

天体物理学 · 物理学 2009-11-10 Nissim Kanekar , Ravi Subrahmanyan , Jayaram N. Chengalur , Vicky Safouris

The cooling transition temperature gas in the interstellar medium (ISM), traced by the high ions, Si IV, C IV, N V, and O VI, helps to constrain the flow of energy from the hot ISM with T >10^6 K to the warm ISM with T< 2x10^4 K. We…

星系天体物理 · 物理学 2015-05-20 N. Lehner , W. F. Zech , J. C. Howk , B. D. Savage

We present XMM-Newton observations around the sightline of Mrk 421. The emission spectrum of the Milky Way circumgalactic medium (CGM) shows that a two phase model is a better fit to the data compared to a single phase model; in addition to…

星系天体物理 · 物理学 2023-10-27 Joy Bhattacharyya , Sanskriti Das , Anjali Gupta , Smita Mathur , Yair Krongold

We study the properties of low-column density gas clumps in the halo of the Milky Way based on high-resolution 21-cm observations. Using interferometric data from the WSRT and the VLA we study HI emission at low-, intermediate- and high…

星系天体物理 · 物理学 2015-05-13 N. Ben Bekhti , P. Richter , B. Winkel , F. Kenn , T. Westmeier

Surrounding the Milky Way (MW) is the circumgalactic medium (CGM), an extended reservoir of hot gas that has significant implications for the evolution of the MW. We used the HaloSat all-sky survey to study the CGM's soft X-ray emission in…

We have developed a new X-ray absorption model, called {\tt IONeq}, which computes the optical depth $\tau(E)$ simultaneously for ions of all abundant elements, assuming ionization equilibrium and taking into account turbulent broadening.…

高能天体物理现象 · 物理学 2017-12-20 Efrain Gatuzz , Eugene Churazov
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