搜索结果: 1-15 共查到“星系与宇宙学 Absorption”相关记录20条 . 查询时间(0.275 秒)
X-ray absorption by the low-redshift intergalactic medium: A numerical study of the Lambda cold dark matter model
theory intergalactic medium
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2014/12/24
Using a hydrodynamic simulation of a cold dark matter universe with a cosmological constant, we investigate the "X-ray forest" absorption imprinted on the spectra of background quasars by the interven...
Water absorption from line-of-sight clouds toward W49A
W49 formation
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2014/12/24
We have observed six clouds along the line of sight toward W49A using the Submillimeter Wave Astronomy Satellite and several ground-based observatories. The ortho-H2O 110 → 101 and OH (1665 and 1667 M...
X-Ray Absorption Line Spectroscopy of the Galactic Hot Interstellar Medium
Cyg X–2 V801 Ara
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2014/12/24
We present an X-ray absorption line spectroscopic study of the large-scale hot interstellar medium (HISM) in the Galaxy. We detect Ne IX Kα absorption lines in the Chandra grating spectra of seven Gal...
Warm-hot gas in and around the Milky Way: Detection and implications of OVII absorption toward LMC X-3
LMC X–3 ISM
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2014/12/24
X-ray absorption lines of highly ionized species such as O VII at about zero redshift have been firmly detected in the spectra of several active galactic nuclei. However, the location of the absorbing...
X-Ray Absorption Spectroscopy of the Multiphase Interstellar Medium: Oxygen and Neon Abundances
ISM 4U 1820–303
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2014/12/24
X-ray absorption spectroscopy provides a powerful tool in determining the metal abundances in various phases of the interstellar medium (ISM). We present a case study of the sight line toward 4U 1820-...
Chandra Detection of Fe XVII in Absorption: Iron Abundance in the Hot Gaseous Interstellar Medium
4U 1820–303 abundances
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2014/12/24
The iron depletion level and the gas-phase iron abundance in the hot (~106 K) interstellar medium (ISM) are critical to our understanding of its energy balance as well as the thermal sputtering, cooli...
The Galactic Central Diffuse X-Ray Enhancement: A Differential Absorption/Emission Analysis
3C 273 Mrk 421
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2014/12/23
The soft X-ray background shows a general enhancement toward the inner region of the Galaxy. But whether this enhancement is a local feature (e.g., a superbubble within a distance of 200 pc) and/or a ...
Limits on Hot Galactic Halo Gas from X-Ray Absorption Lines
4U 1957+11 Mrk 421 LMC X–3
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2014/12/23
Although the existence of large-scale hot gaseous halos around massive disk galaxies has been theorized for a long time, there is yet very little observational evidence. We report the Chandra and XMM-...
Strong CH+ J = 1–0 emission and absorption in DR21
CH+ DR21
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2014/12/20
We report the first detection of the ground-state rotational transition of the methylidyne cation CH+ towards the massive star-forming region DR 21 with the HIFI instrument onboard the Herschel satell...
The intergalactic medium over the last 10 billion years I: Lyman alpha absorption and physical conditions
intergalactic medium hydrodynamic
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2014/12/20
The intergalactic medium (IGM) is the dominant reservoir of baryons at all cosmic epochs. We investigate the evolution of the IGM from z=2-0 in 48 Mpc/h, 110-million particle cosmological hydrodynamic...
USING 21 cm ABSORPTION IN SMALL IMPACT PARAMETER GALAXY-QUASAR PAIRS TO PROBE LOW-REDSHIFT DAMPED AND SUB-DAMPED Ly alpha SYSTEMS
low-redshift damped Lyα (DLA) sub-DLA quasar absorbers
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2014/12/20
To search for low-redshift damped Lyα (DLA) and sub-DLA quasar absorbers, we have conducted a 21 cm absorption survey of radio-loud quasars at small impact parameters to foreground galaxies selected f...
Observations of Mg II Absorption Near z ~ 1 Galaxies Selected From The DEEP2 Redshift Survey
Observations Absorption Galaxies Selected Redshift Survey
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2011/10/13
We study the frequency of Mg II absorption in the outer haloes of galaxies at z = 0.6 - 1.4 (with median z = 0.87), using new spectra obtained of ten background quasars with galaxy impact parameters o...
The effects of X-ray absorption variability in NGC 4395
galaxies: active – galaxies: individual: NGC 4395 – X-rays: galaxies
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2011/10/8
We present a new X-ray analysis of the dwarf Seyfert galaxy NGC 4395, based on two archival XMM-Newton and Suzaku observations. This source is well known for a series of remarkable properties: one of ...
Determination of the Mean HI Absorption of the Intergalactic Medium
Quasar absorption lines—galaxies intergalactic medium
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2010/9/15
In recent years, the Lyman-α forest in quasar spectra has been used, together with N-body simulations, to determine the underlying matter distribution in the intergalactic medium (IGM). One of the key...
Associated HI Absorption in the z = 3.4 Radio Galaxy B2 0902+343 Observed with the GMRT
absorption lines radio lines galaxies radio galaxies individual (0902 C 343)
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2009/5/14
We have made observations of the associated HI absorption of a
high redshift radio galaxy 0902C34 at z D 3:395 with the Giant Meterwave
Radio Telescope in the 3231MHz band.We find a narrowabsorptio...