Neptune's ring arcs from VLT/SPHERE-IRDIS near-infrared observations

Stars in the earliest phases of their formation, i.e., those accreting the main component of their final mass, are deeply embedded within dense cores of dust and molecular material. Because of the high line-of-sight extinction and the large amount of circumstellar material, stellar emission is reprocessed by dust into long wavelength radiation, typically in the far-infrared and sub-millimeter bands. Consequently, the youngest sources are strong submillimeter continuum sources, and often undetectable as point sources in the near-infrared and optical. The most deeply embedded of these sources have been labelled “Class 0” sources by André, Ward-Thompson, & Barsony (1994), in an extension of the spectral energy distribution classification scheme first proposed by Adams, Lada, & Shu (1987).

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Comparison of satellite microwave backscattering (ASCAT) and visible/near-infrared reflectances (PARASOL) for the estimation of aeolian aerodynamic roughness length in arid and semi-arid regions

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-5-2933-2012 ◽

2012 ◽

Vol 5 (2) ◽

pp. 2933-2957

Author(s):

C. Prigent ◽

C. Jiménez ◽

J. Catherinot

Keyword(s):

Arid Regions ◽

Near Infrared ◽

Roughness Length ◽

Aerodynamic Roughness Length ◽

Sources Of Information ◽

Transport Models ◽

Dust Transport ◽

Infrared Observations ◽

Aerodynamic Roughness ◽

Semi Arid

Abstract. Previous studies examined the possibility to estimate the aeolian aerodynamic roughness length from satellites, either from visible/near-infrared observations or from microwave backscattering measurements. Here we compare the potential of the two approaches and propose to merge the two sources of information to benefit from their complementary aspects, i.e. the high spatial resolution of the visible/near-infrared (PARASOL part of the A-Train) and the independence from atmospheric contamination of the active microwaves (ASCAT on board MetOp). A global map of the aeolian aerodynamic roughness length at 6 km resolution is derived, for arid and semi-arid regions. It shows very good consistency with the existing information on the properties of these surfaces. The dataset is available to the community, for use in atmospheric dust transport models.

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Near-infrared observations of the Fornax dwarf galaxy

Astronomy and Astrophysics ◽

10.1051/0004-6361:20066788 ◽

2007 ◽

Vol 467 (3) ◽

pp. 1025-1036 ◽

Cited By ~ 37

Author(s):

M. Gullieuszik ◽

E. V. Held ◽

L. Rizzi ◽

I. Saviane ◽

Y. Momany ◽

...

Keyword(s):

Near Infrared ◽

Dwarf Galaxy ◽

Infrared Observations

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Secondary eclipses of WASP-18b – near-infrared observations with the Anglo-Australian Telescope, the Magellan Clay Telescope and the LCOGT network

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/sty3381 ◽

2018 ◽

Vol 483 (4) ◽

pp. 5110-5122 ◽

Cited By ~ 2

Author(s):

L Kedziora-Chudczer ◽

G Zhou ◽

J Bailey ◽

D D R Bayliss ◽

C G Tinney ◽

...

Keyword(s):

Near Infrared ◽

Infrared Observations

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Near-Infrared Observations of KH 15D through the 2003 February Eclipse

The Astronomical Journal ◽

10.1086/425549 ◽

2004 ◽

Vol 128 (6) ◽

pp. 2977-2980 ◽

Cited By ~ 3

Author(s):

Roger Knacke ◽

Sergio Fajardo-Acosta ◽

A. T. Tokunaga

Keyword(s):

Near Infrared ◽

Infrared Observations

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Exploring the inner parsecs of active galactic nuclei using near-infrared high resolution polarimetric simulations with MontAGN

Astronomy and Astrophysics ◽

10.1051/0004-6361/201731438 ◽

2018 ◽

Vol 612 ◽

pp. A69 ◽

Cited By ~ 8

Author(s):

L. Grosset ◽

D. Rouan ◽

D. Gratadour ◽

D. Pelat ◽

J. Orkisz ◽

...

Keyword(s):

Active Galactic Nuclei ◽

Optical Depth ◽

Near Infrared ◽

Galactic Nuclei ◽

Constant Density ◽

Characteristic Model ◽

Infrared Observations ◽

Current Estimation ◽

Direct Light ◽

Ngc 1068

Aims. In this paper we aim to constrain the properties of dust structures in the central first parsecs of active galactic nuclei (AGN). Our goal is to study the required optical depth and composition of different dusty and ionised structures. Methods. We developed a radiative transfer code called Monte Carlo for Active Galactic Nuclei (MontAGN), which is optimised for polarimetric observations in the infrared. With both this code and STOKES, designed to be relevant from the hard X-ray band to near-infrared wavelengths, we investigate the polarisation emerging from a characteristic model of the AGN environment. For this purpose, we compare predictions of our models with previous infrared observations of NGC 1068, and try to reproduce several key polarisation patterns revealed by polarisation mapping. Results. We constrain the required dust structures and their densities. More precisely, we find that the electron density inside the ionisation cone is about 2.0 × 109 m−3. With structures constituted of spherical grains of constant density, we also highlight that the torus should be thicker than 20 in term of K-band optical depth to block direct light from the centre. It should also have a stratification in density: a less dense outer rim with an optical depth at 2.2 μm typically between 0.8 and 4 for observing the double scattering effect previously proposed. Conclusions. We bring constraints on the dust structures in the inner parsecs of an AGN model supposed to describe NGC 1068. When compared to observations, this leads to an optical depth of at least 20 in the Ks band for the torus of NGC 1068, corresponding to τV ≈ 170, which is within the range of current estimation based on observations. In the future, we will improve our study by including non-uniform dust structures and aligned elongated grains to constrain other possible interpretations of the observations.

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Near-infrared observations of the Z about 2.3 IRAS source FSC 10214 + 4724

The Astrophysical Journal ◽

10.1086/186195 ◽

1991 ◽

Vol 381 ◽

pp. L55 ◽

Cited By ~ 10

Author(s):

B. T. Soifer ◽

G. Neugebauer ◽

J. R. Graham ◽

K. Matthews ◽

J. M. Mazzarella ◽

...

Keyword(s):

Near Infrared ◽

Iras Source ◽

Infrared Observations

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Assessing the Stability of Surface Lights for use in Retrievals of Nocturnal Atmospheric Parameters

10.5194/amt-2019-103 ◽

2019 ◽

Author(s):

Jeremy E. Solbrig ◽

Steven D. Miller ◽

Jianglong Zhang ◽

Lewis Grasso ◽

Anton Kliewer

Keyword(s):

Near Infrared ◽

Correlation Coefficients ◽

Visible Spectrum ◽

Light Sources ◽

Infrared Observations ◽

Spatially Resolved ◽

Relative Standard ◽

Geometric Variables ◽

The Stability

Abstract. Detection and characterization of aerosols is inherently limited at night due to a lack of sensitivity—information typically provided by visible spectrum observations. The VIIRS Day/Night Band (DNB) onboard the Suomi-NPP satellite is a first-of-its-kind calibrated sensor capable of collecting visible/near-infrared observations during both day and night. Multiple studies have suggested that anthropogenic light emissions such as those from cities and gas flares may be useable as light sources for retrieval of atmospheric properties including cloud and aerosol optical depth. However, their use in this capacity requires proper characterization of their intrinsic variation, which represents a source of retrieval uncertainty. In this study we use 18 months of cloud-cleared VIIRS data collected over five selected geographic domains to assess the stability of anthropogenic light emissions and their response to varied satellite and lunar geometries. Timeseries are developed for each location in each domain for DNB radiance, four infrared channels, and satellite and lunar geometric variables, and spatially-resolved correlation coefficients are computed between DNB radiance and each of the other variables. This analysis finds that while many emissive light sources are too unstable to be used reliably for atmospheric retrievals, some sources exhibit a sufficient stability (relative standard deviation

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