scholarly journals Fullerenes, PAHs, Amino Acids and High Energy Astrophysics

2014 ◽  
Vol 1 (1) ◽  
pp. 38-41
Author(s):  
Susana Iglesias-Groth
Keyword(s):  
Amino Acids ◽  
Near Infrared ◽  
High Energy ◽  
Laboratory Work ◽  
Near Ir ◽  
Diffuse Interstellar Bands ◽  
The Galaxy ◽  
Spectral Characterisation ◽  
Fullerene Formation ◽  
Ir Bands

We present theoretical, observational and laboratory work on the spectral properties of fullerenes and hydrogenated fullerenes. Fullerenes in its various forms (individual, endohedral, hydrogenated, etc.) can contribute to the UV bump in the extinction curves measured in many lines of sight of the Galaxy. They can also produce a large number of absorption features in the optical and near infrared which could be associated with diffuse interstellar bands. We summarise recent laboratory work on the spectral characterisation of fullerenes and hydrogenated fullerenes (for a range of temperatures). The recent detection of mid-IR bands of fullerenes in various astrophysical environments (planetary nebulae, reflection nebulae) provide additional evidence for a link between fullerene families and diffuse interstellar bands. We describe recent observational work on near IR bands of C<sub>60</sub><sup>+</sup> in a protoplanetary nebula which support fullerene formation during the post-AGB phase. We also report on the survival of fullerenes to irradiation by high energy particles and gamma photons and laboratory work to explore the chemical  reactions that take place when fullerenes are exposed to this radiations in the presence of water, ammonia and other molecules as a potential path to form amino acids.

scholarly journals Characterization of conichalcite by SEM, FTIR, Raman and electronic reflectance spectroscopy

2005 ◽  
Vol 69 (2) ◽  
pp. 155-167 ◽  
Author(s):  
B. J. Reddy ◽  
R. L. Frost ◽  
W. N. Martens
Keyword(s):  
Near Infrared ◽  
Adsorbed Water ◽  
Reflectance Spectroscopy ◽  
Sem Images ◽  
X Ray ◽  
Near Ir ◽  
Ir Reflectance ◽  
Yavapai County ◽  
Ir Bands

AbstractThe mineral conichalcite from the western part of Bagdad mine, Bagdad, Eureka District, Yavapai County, Arizona, USA has been characterized by electronic, near-infrared (NIR), Raman and infrared (IR) spectroscopy. Scanning electron microscopy (SEM) images show that the mineral consists of bundles of fibres. Calculations based on the results of the energy dispersive X-ray analyses on a stoichiometric basis show the substitution of arsenate by 12 wt.% of phosphate in the mineral. Raman and IR bands are assigned in terms of the fundamental modes of AsO43− and PO43− molecules and are related to the mineral structure. Near-IR reflectance spectroscopy shows the presence of adsorbed water and hydroxyl units in the mineral. The Cu(II) coordination polyhedron in conichalcite can have at best pseudo-tetragonal geometry. The crystal field and tetragonal field parameters of the Cu(II) complex were calculated and found to agree well with the values reported for known tetragonal distortion octahedral complexes.

Efforts to Quantify Changes in Near-Infrared Spectra Caused by the Influence of Water, pH, Ionic Strength, and Differences in Physical State

1995 ◽  
Vol 49 (2) ◽  
pp. 181-187 ◽  
Author(s):  
James B. Reeves
Keyword(s):  
Amino Acids ◽  
Ionic Strength ◽  
Infrared Spectra ◽  
Physical State ◽  
Near Infrared ◽  
Near Ir ◽  
Near Infrared Spectra ◽  
Influence Of Water ◽  
Water Ph ◽  
Crystalline Sugars

The application of near-infrared spectroscopy to high-moisture samples has shown that the accuracy does not match that found for dried materials. The objective of this work was to attempt to quantify the effects of water, pH, ionic strength, and differences in physical state on near-infrared spectra with the use of model compounds. Spectra were compared by regression analysis of second derivatives after spectral subtraction of water. Spectra from 4900 to 4100 cm−1 at a resolution of 4 cm−1 were examined. Regression results showed spectra to be more similar among amorphous sugars and among dissolved sugars than among crystalline sugars. Also, spectra of amorphous sugars were statistically more similar to spectra of dissolved sugars than to spectra of crystalline sugars. While the spectra of one dissolved or amorphous sugar were statistically similar, this was not true for amino acids. Spectra of amorphous amino acids were similar to those of crystalline forms and neither were similar to those of dissolved forms. Spectrally, polymeric carbohydrates appeared very similar to one another when dry and behaved like amino acids when wet. Finally, efforts to directly relate these findings to near-IR spectroscopy calibration problems will require further research.

scholarly journals Inflows and Outflows in Nearby AGN from Integral Field Spectroscopy

2009 ◽  
Vol 5 (S267) ◽  
pp. 290-298 ◽  
Author(s):  
Thaisa Storchi-Bergmann
Keyword(s):  
Near Infrared ◽  
Stellar Kinematics ◽  
Gas Emission ◽  
Ionized Gas ◽  
Integral Field Spectroscopy ◽  
Near Ir ◽  
Field Spectroscopy ◽  
The Galaxy ◽  
Mass Outflow ◽  
Integral Field

AbstractI report recent results on the kinematics of the inner few hundred parsecs (pc) around nearby active galactic nuclei (AGN) at a sampling of a few pc to a few tens of pc, using optical and near-infrared (near-IR) integral field spectroscopy obtained with the Gemini telescopes. The stellar kinematics of the hosts — comprised mostly of spiral galaxies — are dominated by circular rotation in the plane of the galaxy. Inflows with velocities of ~50 km s−1 have been observed along nuclear spiral arms in (optical) ionized gas emission for low-luminosity AGN and in (near-IR) molecular gas emission for higher-luminosity AGN. We have also observed gas rotating in the galaxy plane, sometimes in compact (few tens of pc) disks which may be fuelling the AGN. Outflows have been observed mostly in ionized gas emission from the narrow-line region, whose flux distributions and kinematics frequently correlate with radio flux distributions. Channel maps along the emission-line profiles reveal velocities as high as ~ 600 km s−1. Mass outflow rates in ionized gas range from 10−2 to 10−3M⊙ yr−1 and are 10–100 times larger than the mass accretion rates on to the AGN, supporting an origin for the bulk of the outflow in gas from the galaxy plane entrained by a nuclear jet or accretion disk wind.

scholarly journals Near Infrared Star Counts as a Probe of Asymmetries in the Galaxy's Disk

1996 ◽  
Vol 169 ◽  
pp. 59-60
Author(s):  
James E. Rhoads
Keyword(s):  
Near Infrared ◽  
Mass Density ◽  
3D Structure ◽  
List Type ◽  
Galactic Latitude ◽  
Giant Stars ◽  
Spiral Density Waves ◽  
Near Ir ◽  
The Galaxy ◽  
Infrared Star

I have recently started an observing program to study the distribution of dynamically old giant stars in the disk, looking for (i) large amplitude spiral arms and (ii) small amplitude corrugations. (i)Theoretical studies of spiral density waves usually assume that the mass density contrast is weak and the waves linear. Recent observations in red and near-IR light (e.g., Elmegreen and Elmegreen 1984; Rix and Zaritsky 1994), coupled with stellar population models, suggest otherwise. In the Galaxy, we can compare observations of diffuse NIR light and of individual stars, eliminating the need for population modeling. Moreover, we can estimate distances to stars to learn about 3D structure.(ii)Recent work by Malhotra (1994a; 1994b) has shown that the midplane of the molecular and atomic gas differs from the nominal (Galactic latitude b = 0°) plane by up to 50 pc in the inner Galaxy. Various observations (Djorgovski & Sosin 1989, Freudenreich et al 1994, Carney & Seltzer 1993) show that the stellar distribution also deviates from b = 0. We will choose fields to test the possibility that the stars behave like the gas. This constrains theories of the corrugations; e.g., if old stars participate then magnetic fields aren't the cause.

scholarly journals Site-Specific Labeling of Proteins with Near-IR Dyes

2018 ◽  
Author(s):  
Chen-Ming Lin ◽  
Syed Muhammad Usama ◽  
Kevin Burgess
Keyword(s):  
Amino Acids ◽  
Fluorescent Probes ◽  
Near Infrared ◽  
Light Penetration ◽  
Selective Labeling ◽  
Site Specific ◽  
Physiological Conditions ◽  
Neutral Ph ◽  
Near Ir ◽  
Aqueous Environments

Convenient labeling of proteins is important for observing its function under physiological conditions. &nbsp;In tissues particularly, heptamethine cyanine dyes (Cy-7) are valuable because they absorb in near infrared (NIR) region (750 &ndash; 900 nm) where light penetration is maximal.&nbsp; In this work, we found Cy-7 dyes with a meso-Cl functionality covalently binding to proteins with free Cys residues under physiological conditions (aqueous environments, at near neutral pH, and 37 &deg;C).&nbsp; It transpired that the meso-Cl of the dye was displaced by free thiols in protein, while nucleophilic side-chains from amino acids like Tyr, Lys, and Ser did not react.&nbsp; This finding shows a new possibility for convenient and selective labeling of proteins with near-IR fluorescent probes.

scholarly journals The Promise of Recent and Future Observatories and Instruments

2013 ◽  
Vol 9 (S297) ◽  
pp. 389-398
Author(s):  
L Kaper
Keyword(s):  
Potential Role ◽  
Near Infrared ◽  
Local Group ◽  
Infrared Wavelength ◽  
Stellar Spectroscopy ◽  
Diffuse Interstellar Bands ◽  
The Galaxy ◽  
Substantial Progress ◽  
Large Telescopes ◽  
Made In

AbstractThe identification of the carrier(s) of diffuse interstellar bands (DIBs) is one of the oldest mysteries in stellar spectroscopy. With the advent of 8-10m-class telescopes substantial progress has been made in measuring the properties of DIBs in the optical and near-infrared wavelength domain, not only in the Galaxy, but also in different environments encountered in Local Group galaxies and beyond. Still, the DIB carriers have remained unidentified. The coming decade will witness the development of extremely large telescopes (GMT, TMT and E-ELT) and their instrumentation. In this overview I will highlight the current instrumentation plan of these future observatories, emphasizing their potential role in solving the enigma of the DIBs.

scholarly journals Site-Specific Labeling of Proteins with Near-IR Heptamethine Cyanine Dyes

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2900 ◽  
Author(s):  
Chen-Ming Lin ◽  
Syed Usama ◽  
Kevin Burgess
Keyword(s):  
Amino Acids ◽  
Fluorescent Probes ◽  
Near Infrared ◽  
Cyanine Dyes ◽  
Light Penetration ◽  
Selective Labeling ◽  
Site Specific ◽  
Physiological Conditions ◽  
Near Ir ◽  
Aqueous Environments

Convenient labeling of proteins is important for observing its function under physiological conditions. In tissues particularly, heptamethine cyanine dyes (Cy-7) are valuable because they absorb in the near-infrared (NIR) region (750–900 nm) where light penetration is maximal. In this work, we found Cy-7 dyes with a meso-Cl functionality covalently binding to proteins with free Cys residues under physiological conditions (aqueous environments, at near neutral pH, and 37 °C). It transpired that the meso-Cl of the dye was displaced by free thiols in protein, while nucleophilic side-chains from amino acids like Tyr, Lys, and Ser did not react. This finding shows a new possibility for convenient and selective labeling of proteins with NIR fluorescent probes.

High-energy gamma-ray sources in the VVV survey – I. The blazars

2019 ◽  
Vol 491 (3) ◽  
pp. 3448-3460
Author(s):  
Ana Pichel ◽  
Laura G Donoso ◽  
Laura D Baravalle ◽  
M Victoria Alonso ◽  
Adrián C Rovero ◽  
...  
Keyword(s):  
Interstellar Dust ◽  
Near Infrared ◽  
Gamma Ray ◽  
Galactic Plane ◽  
High Energy ◽  
Wide Field ◽  
Near Ir ◽  
Spectrum Radio ◽  
Energy Gamma ◽  
Learning Analysis

ABSTRACT There is a lack of blazar detections in the galactic plane area, even in the most recent blazar catalogues, mainly due to incompleteness resulting from interstellar dust and stellar contamination of our Galaxy. The VISTA Variables in the Vía Láctea survey (VVV) aims to map variable sources towards the galactic plane in the near-infrared (IR). There are three catalogued and one candidate blazars in the VVV area, which are also detected by Fermi-LAT in the gamma-ray band and by the Wide-field Infrared Survey Explorer (WISE) at mid-IR wavelengths. We study the physical properties of these blazars in order to use them as a reference that would allow us to find counterparts of other unidentified gamma-ray sources in the future. All four sources have VVV counterparts, and two of them, 5BZUJ1731−3003 and 5BZQJ1802−3940 are also associated with WISE sources. They present very different properties compared with stellar or extragalactic objects. Their VVV Ks light curves show significant variability, and are characterized using a machine learning analysis. In particular, the blazar 5BZQJ1802−3940, a flat spectrum radio quasar, exhibits the smallest uncertainties in the Fermi-LAT position and it is a bright WISE source. Its near-IR properties in the colour–magnitude and colour–colour diagrams are very different from the stars and extragalactic objects in the field. It has the highest amplitude in the Ks differential light curve and fractional variability amplitude. This pilot study will allow us to search for and identify other blazars hidden behind the Galactic plane using the VVV survey data base.

scholarly journals Near-IR Diffuse Interstellar Bands in SDSS-III APOGEE Spectra

2013 ◽  
Vol 9 (S297) ◽  
pp. 68-73 ◽  
Author(s):  
G. Zasowski ◽  
B. Ménard
Keyword(s):  
Preliminary Investigation ◽  
First Year ◽  
Apparent Velocity ◽  
Strongly Correlated ◽  
Homogeneous Sample ◽  
Near Ir ◽  
Diffuse Interstellar Bands ◽  
The Galaxy ◽  
Statistical Studies ◽  
Band Spectra

AbstractUsing high resolution H-band spectra from first-year observations of the SDSS-III APOGEE survey, we have searched for the presence of Diffuse Interstellar Bands (DIBs) towards several thousand stars and obtained ~7 000 robust detections spanning a broad range of Galactic environments. This represents the largest homogeneous sample of DIB systems in terms of both size and sky coverage, which can be used for various statistical studies. For example, we find the strength of the most prominent near-IR DIB (at 1.5723 μm) to be strongly correlated with line-of-sight dust extinction, and its apparent velocity appears to trace that of the Galactic CO emission. The ability to work at near-IR wavelengths allows us to probe lines of sight penetrating through the dusty disk of the Galaxy, spanning a range of about 8 magnitudes of extinction. This preliminary investigation illustrates how a large sample of DIBs can serve as a useful tool to probe the structure of the Galaxy and the chemistry of the interstellar medium.

scholarly journals A new near-IR window of low extinction in the Galactic plane

2018 ◽  
Vol 616 ◽  
pp. A26 ◽  
Author(s):  
Dante Minniti ◽  
Roberto K. Saito ◽  
Oscar A. Gonzalez ◽  
Javier Alonso-García ◽  
Marina Rejkuba ◽  
...  
Keyword(s):  
Near Infrared ◽  
Milky Way ◽  
Galactic Plane ◽  
Structural Constraints ◽  
Magnitude Distribution ◽  
Near Ir ◽  
Disk Structure ◽  
The Galaxy ◽  
The Mean ◽  
Red Clump

Aims. The windows of low extinction in the Milky Way (MW) plane are rare but important because they enable us to place structural constraints on the opposite side of the Galaxy, which has hither to been done rarely. Methods. We use the near-infrared (near-IR) images of the VISTA Variables in the Vía Láctea (VVV) Survey to build extinction maps and to identify low extinction windows towards the Southern Galactic plane. Here we report the discovery of VVV WIN 1713−3939, a very interesting window with relatively uniform and low extinction conveniently placed very close to the Galactic plane. Results. The new window of roughly 30 arcmin diameter is located at Galactic coordinates (l, b) = (347.4, −0.4) deg. We analyse the VVV near-IR colour-magnitude diagrams in this window. The mean total near-IR extinction and reddening values measured for this window are AKs = 0.46 and E(J − Ks) = 0.95. The red clump giants within the window show a bimodal magnitude distribution in the Ks band, with peaks at Ks = 14.1 and 14.8 mag, corresponding to mean distances of D = 11.0 ± 2.4 and 14.8 ± 3.6 kpc, respectively. We discuss the origin of these red clump overdensities within the context of the MW disk structure.

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