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We present a reanalysis of the HeII Lyman alpha absorption towards the quasars HS1700+6416 and HE2347-4342 using new high S/N, optical observations. An alternative analysis method is applied, which fits the high quality, optical HI data…

天体物理学 · 物理学 2009-11-11 C. Fechner , D. Reimers

JWST gives a unique access to the physical and chemical structure of inner disks ($<10$~au), where the majority of the planets are forming. However, the interpretation of mid-infrared (mid-IR) spectra requires detailed thermo-chemical…

地球与行星天体物理 · 物理学 2024-10-30 Benoît Tabone , Ewine F. van Dishoeck , John H. Black

One of the most promising probes to complement current standard cosmological surveys is the HI intensity map, i.e. the distribution of temperature fluctuations in neutral hydrogen. In this paper we present calculations of the 2-point…

宇宙学与河外天体物理 · 物理学 2024-06-24 Anut Sangka , David Bacon

We present space-based ultraviolet/optical photometry and spectroscopy with the Swift Ultra-Violet/Optical Telescope and Hubble Space Telescope, respectively, along with ground-based optical photometry and spectroscopy and near-infrared…

Observations of 21-cm radio emission by neutral hydrogen at redshifts z ~ 0.5 to ~ 2.5 are expected to provide a sensitive probe of cosmic dark energy. This is particularly true around the onset of acceleration at z ~ 1, where traditional…

宇宙学与河外天体物理 · 物理学 2010-07-22 Tzu-Ching Chang , Ue-Li Pen , Kevin Bandura , Jeffrey B. Peterson

We study the near-infrared (NIR) scattering in LDN 1642, its correlation with the cloud structure, and the ability of dust models to simultaneously explain sub-millimetre emission, NIR extinction, and NIR scattering. We use observations…

星系天体物理 · 物理学 2020-11-25 Mika Juvela , Sharma Neha , Emma Mannfors , Mika Saajasto , Nathalie Ysard , Veli-Matti Pelkonen

We present an analysis combining the simultaneous measurement of intergalactic absorption by hydrogen (H I), helium (He II) and oxygen (O VI) in UV and optical quasar spectra. The combination of the H I and He II Lyman-alpha forests through…

宇宙学与河外天体物理 · 物理学 2019-09-04 Sean Morrison , Matthew M. Pieri , David Syphers , Tae-Sun Kim

We investigate the correlation between OH and H2 column densities in diffuse Galactic clouds, in order to identify potential molecular tracers of interstellar H2. For this, we analyse near-UV spectra extracted from the ESO/VLT archives…

星系天体物理 · 物理学 2023-06-09 Katherine Rawlins , Bhaswati Mookerjea

We present a study of the cold atomic hydrogen (HI) content of molecular clouds simulated within the SILCC-Zoom project. We produce synthetic observations of HI at 21 cm including HI self-absorption (HISA) and observational effects. We find…

星系天体物理 · 物理学 2022-03-14 D. Seifried , H. Beuther , S. Walch , J. Syed , J. D. Soler , P. Girichidis , R. Wünsch

In this letter, 21 cm intensity maps acquired at the Green Bank Telescope are cross-correlated with large-scale structure traced by galaxies in the WiggleZ Dark Energy Survey. The data span the redshift range 0.6 < z < 1 over two fields…

STIS Echelle observations at a resolution of 10 km/s and UVES/VLT spectroscopy at a resolution of 7 km/s of the luminous QSO HE 0515-4414 (z_em = 1.73, B = 15.0) reveal four intervening O VI absorption systems in the redshift range 1.2 <…

天体物理学 · 物理学 2009-11-06 Dieter Reimers , Robert Baade , Hans-Juergen Hagen , Sebastian Lopez

The gas-to-dust ratio of reddened stars in the Milky Way (MW), the Magellanic Clouds, and in general is usually expressed as a linear relation between the hydrogen column density, N(H), and the reddening, E(B-V), or extinction in the V band…

星系天体物理 · 物理学 2021-04-21 Robert E. Butler , Samir Salim

Diffuse gamma-ray emission from interstellar clouds results largely from cosmic ray (CR) proton collisions with ambient gas, regardless of the gas state, temperature, or dust properties of the cloud. The interstellar medium is predominantly…

高能天体物理现象 · 物理学 2017-01-11 Ryan D. Abrahams , Alex Teachey , Timothy A. D. Paglione

We present a complete catalogue of 27 O VI absorbers at low redshift (0.12 < z < 0.5) from a blind survey of 16 QSO echelle spectra in the HST/STIS data archive. These absorbers are identified based only upon matching line profiles and the…

天体物理学 · 物理学 2009-11-13 Christopher Thom , Hsiao-Wen Chen

We present column density measurements of the HD molecule in the interstellar gas toward 17 Galactic stars. The values for the seven most heavily reddened sightlines, with E(B-V) = 0.38-0.72, are derived from observations with the Far…

天体物理学 · 物理学 2008-11-26 S. Lacour , M. K. Andre , P. Sonnentrucker , F. Le Petit , D. E. Welty , J. -M. Desert , R. Ferlet , E. Roueff , D. G. York

Understanding the intrinsic colors of Type Ia supernovae (SNe Ia) is important to their use as cosmological standard candles. Understanding the effects of reddening and redshift on the observed colors are complicated and dependent on the…

高能天体物理现象 · 物理学 2017-06-15 Peter J. Brown , Nancy J. Landez , Peter A. Milne , Maximilian D. Stritzinger

We present a search for associated HI 21 cm absorption in a sample of 29 radio-loud active galactic nuclei (AGNs) at $0.7 < z < 1$, carried out with the upgraded Giant Metrewave Radio Telescope. We detect HI 21 cm absorption against none of…

星系天体物理 · 物理学 2022-03-30 Suma Murthy , Raffaella Morganti , Nissim Kanekar , Tom Oosterloo

We investigate the possibility of probing the large scale structure in the universe at large redshifts by studying fluctuations in the redshifted 1420 MHz emission from the neutral hydrogen (HI) at early epochs. The neutral hydrogen content…

天体物理学 · 物理学 2009-11-07 Somnath Bharadwaj , Shiv K. Sethi

With a new joint-deconvolution pipeline, we combine the single-dish and interferometric atomic hydrogen (HI) data of M51 observed by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) (FEASTS program) and the Very Large Array…

Water photodissociation in the 114 - 144 nm UV range forms excited OH which emits at mid-infrared wavelengths via highly excited rotational lines. These lines have only been detected with Spitzer in several proto-planetary disks and shocks.…

星系天体物理 · 物理学 2023-03-08 Marion Zannese , Benoît Tabone , Emilie Habart , Franck Le Petit , Ewine F. van Dishoeck , Emeric Bron