scholarly journals The Carnegie Supernova Project II

2020 ◽  
Vol 639 ◽  
pp. A103 ◽  
Author(s):  
M. D. Stritzinger ◽  
F. Taddia ◽  
M. Fraser ◽  
T. M. Tauris ◽  
N. B. Suntzeff ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Electron Capture ◽  
Near Infrared ◽  
Companion Paper ◽  
Infrared Emission ◽  
Light Curves ◽  
Data Set ◽  
Mid Infrared ◽  
Space Telescope ◽  
Infrared Wavelength

We present multiwavelength observations of two gap transients that were followed by the Carnegie Supernova Project-II. The observations are supplemented with data obtained by a number of different programs. Here in the first of two papers, we focus on the intermediate-luminosity red transient (ILRT) designated SNhunt120, while in a companion paper we examine the luminous red novae AT 2014ej. Our data set for SNhunt120 consists of an early optical discovery, estimated to be within three days after outburst, the subsequent optical and near-infrared broadband followup extending over a period of about two months, two visual and two near-infrared wavelength spectra, and Spitzer Space Telescope observations extending from early (+28 d) to late (+1155 d) phases. SNhunt120 resembles other ILRTs such as NGC 300-2008-OT and SN 2008S, and like these other ILRTs, SNhunt120 exhibits prevalent mid-infrared emission at both early and late phases. From the comparison of SNhunt120 and other ILRTs to electron-capture supernova simulations, we find that the current models underestimate the explosion kinetic energy and thereby produce synthetic light curves that overestimate the luminosity. Finally, examination of pre-outburst Hubble Space Telescope images yields no progenitor detection.

scholarly journals Detecting the inner regions of discs around sources of microlensing with Roman Space Telescope

2020 ◽  
Vol 498 (1) ◽  
pp. 1298-1307
Author(s):  
Sedighe Sajadian ◽  
Ali Salehi
Keyword(s):  
Near Infrared ◽  
Infrared Emission ◽  
Light Curves ◽  
Main Peak ◽  
Space Telescope ◽  
Inner Radius ◽  
Nearby Stars ◽  
Infrared Interferometry ◽  
Inner Region ◽  
Near Infrared Emission

ABSTRACT The inner region of circumstellar discs makes an extra near-infrared emission (NIR bump). Detecting and studying these NIR bumps from nearby stars have been done mostly through infrared interferometry. In this work, we study the feasibility of detecting NIR bumps for Galactic bulge stars through microlensing from observations by The Nancy Grace Roman Space Telescope (RST) survey. We first simulate microlensing light curves from source stars with discs in NIR. Four main conclusions can be extracted from the simulations. (i) If the lens is crossing the disc inner radius, two extra and wide peaks appear and the main peak of microlensing light curve is flattened. (ii) In microlensing events with the lens impact parameters larger than the disc inner radius, the disc can break the symmetry of light curves with respect to the time of closest approach. (iii) In caustic-crossing binary microlensing, the discs produce wide peaks right before entering and immediately after exiting from the caustic curves. (iv) The disc-induced perturbations are larger in the W149 filter than in the Z087 filter, unless the lens crosses the disc condensation radius. By performing a Monte Carlo simulation, the probabilities of detecting the disc perturbations by RST are estimated ∼3 and 20 per cent in single and binary microlensing, respectively. We anticipate that RST detects around 109 disc-induced perturbations during its microlensing survey if 5 per cent of its source stars have discs.

The Effect of Chain Length on Mid-Infrared and Near-Infrared Spectra of Aliphatic 1-Alcohols

2017 ◽  
Vol 72 (2) ◽  
pp. 288-296 ◽  
Author(s):  
Michał Kwaśniewicz ◽  
Mirosław A. Czarnecki
Keyword(s):  
Correlation Analysis ◽  
Chain Length ◽  
Near Infrared ◽  
Hydrophobic Interactions ◽  
Principal Component ◽  
Butyl Alcohol ◽  
Two Dimensional ◽  
Data Set ◽  
Mid Infrared ◽  
Spectral Changes

Effect of the chain length on mid-infrared (MIR) and near-infrared (NIR) spectra of aliphatic 1-alcohols from methanol to 1-decanol was examined in detail. Of particular interest were the spectra-structure correlations in the NIR region and the correlation between MIR and NIR spectra of 1-alcohols. An application of two-dimensional correlation analysis (2D-COS) and chemometric methods provided comprehensive information on spectral changes in the data set. Principal component analysis (PCA) and cluster analysis evidenced that the spectra of methanol, ethanol, and 1-propanol are noticeably different from the spectra of higher 1-alcohols. The similarity between the spectra increases with an increase in the chain length. Hence, the most similar are the spectra of 1-nonanol and 1-decanol. Two-dimensional hetero-correlation analysis is very helpful for identification of the origin of bands and may guide selection of the best spectral ranges for the chemometric analysis. As shown, normalization of the spectra pronounces the intensity changes in various spectral regions and provides information not accessible from the raw data. The spectra of alcohols cannot be represented as a sum of the CH3, CH2, and OH group spectra since the OH group is involved in the hydrogen bonding. As a result, the spectral changes of this group are nonlinear and its spectral profile cannot be properly resolved. Finally, this work provides a lot of evidence that the degree of self-association of 1-alcohols decreases with the increase in chain length because of the growing meaning of the hydrophobic interactions. For butyl alcohol and higher 1-alcohols the hydrophobic interactions are more important than the OH OH interactions. Therefore, methanol, ethanol, and 1-propanol have unlimited miscibility with water, whereas 1-butanol and higher 1-alcohols have limited miscibility with water.

scholarly journals 7.3. Sgr A∗ in the mid-infrared reference frame: no evidence of an infrared counterpart, or interaction with nearby sources

1998 ◽  
Vol 184 ◽  
pp. 295-297
Author(s):  
Dan Gezari
Keyword(s):  
Near Infrared ◽  
Reference Frames ◽  
A Priori ◽  
Infrared Emission ◽  
Mid Infrared ◽  
Source Component ◽  
Comparable Accuracy ◽  
Sgr A ◽  
Central Parsec ◽  
Infrared Sources

We have determined the position of Sgr A∗ with respect to the mid-infrared (5-25 m) sources in the central parsec by direct correlation of our 12.4 m array image (Gezari et al. 1994) and the new 2-cm continuum VLA map (Yusef-Zadeh 1997; private communication), without a priori knowledge of any other position determinations. Menten et al. (1997) recently succeeded in registering the radio and near-infrared (2.2 m) reference frames with high precision (+0.03 arcsec) using VLA observations of Sgr A∗, SiO masers and H2O masers. Unfortunately, registering the mid-infrared and radio reference frames with comparable accuracy cannot be done by applying the 2.2 m calibration. Most near-infrared sources have no detectable mid-infrared counterparts, and it is not obvious which of those that do are coincident (if any), since near-infrared and mid-infrared emission generally does not arise from the same physical source component. Dramatic examples of shifts between the brightest near- and mid-infrared peaks can be seen in Orion BN/KL and the Ney-Allen Nebula (Gezari and Backman 1994; Gezari, Backman and Werner 1997) corresponding to 0.1 - 0.5 arcsec if they were located at 8.5 kpc. Further, several Sgr A West IRS sources are displaced significantly in the infrared and radio, suggesting they may actually be compact clusters of objects.

scholarly journals Comparison of Individual and Integrated Inline Raman, Near-Infrared, and Mid-Infrared Spectroscopic Models to Predict the Viscosity of Micellar Liquids

2020 ◽  
Vol 74 (7) ◽  
pp. 819-831 ◽  
Author(s):  
Kiran Haroon ◽  
Ali Arafeh ◽  
Stephanie Cunliffe ◽  
Philip Martin ◽  
Thomas Rodgers ◽  
...  
Keyword(s):  
Consumer Satisfaction ◽  
Near Infrared ◽  
Process Analytical Technology ◽  
Process Efficiency ◽  
Initial Assessment ◽  
Data Sets ◽  
Spectroscopic Techniques ◽  
Signal To Noise ◽  
Data Set ◽  
Mid Infrared

In many industries, viscosity is an important quality parameter which significantly affects consumer satisfaction and process efficiency. In the personal care industry, this applies to products such as shampoo and shower gels whose complex structures are built up of micellar liquids. Measuring viscosity offline is well established using benchtop rheometers and viscometers. The difficulty lies in measuring this property directly in the process via on or inline technologies. Therefore, the aim of this work is to investigate whether proxy measurements using inline vibrational spectroscopy, e.g., near-infrared (NIR), mid-infrared (MIR), and Raman, can be used to predict the viscosity of micellar liquids. As optical techniques, they are nondestructive and easily implementable process analytical tools where each type of spectroscopy detects different molecular functionalities. Inline fiber optic coupled probes were employed; a transmission probe for NIR measurements, an attenuated total reflectance probe for MIR and a backscattering probe for Raman. Models were developed using forward interval partial least squares variable selection and log viscosity was used. For each technique, combinations of pre-processing techniques were trialed including detrending, Whittaker filters, standard normal variate, and multiple scatter correction. The results indicate that all three techniques could be applied individually to predict the viscosity of micellar liquids all showing comparable errors of prediction: NIR: 1.75 Pa s; MIR: 1.73 Pa s; and Raman: 1.57 Pa s. The Raman model showed the highest relative prediction deviation (RPD) value of 5.07, with the NIR and MIR models showing slightly lower values of 4.57 and 4.61, respectively. Data fusion was also explored to determine whether employing information from more than one data set improved the model quality. Trials involved weighting data sets based on their signal-to-noise ratio and weighting based on transmission curves (infrared data sets only). The signal-to-noise weighted NIR–MIR–Raman model showed the best performance compared with both combined and individual models with a root mean square error of cross-validation of 0.75 Pa s and an RPD of 10.62. This comparative study provides a good initial assessment of the three prospective process analytical technologies for the measurement of micellar liquid viscosity but also provides a good basis for general measurements of inline viscosity using commercially available process analytical technology. With these techniques typically being employed for compositional analysis, this work presents their capability in the measurement of viscosity—an important physical parameter, extending the applicability of these spectroscopic techniques.

scholarly journals The mid-infrared Leavitt law for classical Cepheids in the Magellanic Clouds

2020 ◽  
Vol 500 (1) ◽  
pp. 817-837
Author(s):  
Abigail H Chown ◽  
Victoria Scowcroft ◽  
Stijn Wuyts
Keyword(s):  
Hubble Space Telescope ◽  
Zero Point ◽  
Large Magellanic Cloud ◽  
Magellanic Clouds ◽  
Light Curves ◽  
Log P ◽  
Mid Infrared ◽  
Space Telescope ◽  
Classical Cepheids ◽  
Combining Data

ABSTRACT The Cepheid Leavitt Law (LL), also known as the Period–Luminosity relation, is a crucial tool for assembling the cosmic distance ladder. By combining data from the OGLE-IV catalogue with mid-infrared photometry from the Spitzer Space Telescope, we have determined the 3.6 and 4.5 $\mu$m LLs for the Magellanic Clouds using ∼5000 fundamental-mode classical Cepheids. Mean magnitudes were determined using a Monte Carlo Markov Chain (MCMC) template fitting procedure, with template light curves constructed from a subsample of these Cepheids with fully phased, well-sampled light curves. The dependence of the Large Magellanic Cloud LL coefficients on various period cuts was tested, in addition to the linearity of the relationship. The zero-point of the LL was calibrated using the parallaxes of Milky Way Cepheids from the Hubble Space Telescope and Gaia Data Release 2. Our final calibrated relations are M[3.6] = −3.246(±0.008)(log (P) − 1.0) − 5.784(±0.030) and M[4.5] = −3.162(±0.008)(log (P) − 1.0) − 5.751(±0.030).

scholarly journals Visible to Mid-infrared Waveband Photodetector Based on Insulator Capped Asymmetry Black Phosphorous

2021 ◽  
Vol 9 ◽  
Author(s):  
Qi Han ◽  
Yadong Jiang ◽  
Jiayue Han ◽  
Xiang Dong ◽  
Jun Gou
Keyword(s):  
Band Gap ◽  
Dark Current ◽  
Near Infrared ◽  
Photothermal Effect ◽  
Saturable Absorption ◽  
Infrared Band ◽  
Mid Infrared ◽  
Infrared Wavelength ◽  
Black Phosphorous ◽  
Harvesting Process

Processing layer-dependent direct band gap and good absorption coefficient especially in the mid-infrared band, black phosphorous is believed to make a contribution superior to that of graphene in broadband photodetectors. The narrow band gap of 0.3 eV for bulk black phosphorous helps to absorb infrared radiation while a relatively large dark current under zero gate voltage is inevitable. Few layer black phosphorous sheets with asymmetrical thickness sealed in an insulator for protection is designed and explored for photosensitive mechanism in this work. Saturable absorption dominates the light harvesting process in visible light detection and thus limits maximum photocurrent to 3.3 and 1.4 μA for 520 and 650 nm lasers with a dark current of 0.7 μA. While in near-infrared wavelength, a responsivity of 0.12 A/W is inducted for 808 nm free of adsorption saturation even if the incident power is increased to 200 mW/cm2. Discrimination for the origin of the photo-response in short wavelength is conducted and the abnormal negative and nearly constant photocurrent in mid-infrared, irrelevant to inhomogeneous thickness, reveals the photothermal effect in a black phosphorous sheet. This work unravels various photoelectric features in black phosphorous and paves the way to designing more outstanding broadband photodetectors based on black phosphorous.

A full decade (2009-2019) of continuous nightglow observations from the NUV to the NIR

2021 ◽  
Author(s):  
Wolfgang Kausch ◽  
Stefan Noll ◽  
Stefan Kimeswenger ◽  
Sabine Moehler
Keyword(s):  
Wavelength Range ◽  
Near Infrared ◽  
Data Set ◽  
Mesopause Region ◽  
Infrared Wavelength ◽  
Near Ultraviolet ◽  
Very Large Telescope ◽  
Medium Resolution ◽  
Wide Wavelength Range ◽  
Atomic Lines

<p>The airglow emission of the mesopause region comprises molecular bands and atomic lines in the near-ultraviolet to the near-infrared wavelength range, e.g. the prominent roto-vibrational OH bands, a weak FeO/NiO continuum, the green OI line, the NaD doublet and some others. Since ground-based astronomical facilites observe through the Earth's atmosphere, the fingerprint of these emissions is visible in astronomical spectra taken with a telescope.<br>We have assembled a comprehensive data set of about 100,000 spectra in total taken between 1st of October 2009 and 30th of September 2019 with the X-shooter spectrograph, which is mounted at the Very Large Telescope in the Chilean Atacama desert (24.6°S, 70.4°W). This instrument provides medium-resolution spectra covering the entire wavelength range from 0.3 to 2.5μm simultaneously by incorporating three spectral subranges (UVB: 0.3-0.56μm; VIS: 0.56-1.02μm; NIR: 1.02-2.5μm).</p><p>The X-shooter instrument was continuously in operation during the covered period and frequently used by astronomers. Thus, the temporal coverage of the available observations is very dense for astronomical data allowing various airglow studies on time scales from minutes to a full decade. Due to the simultaneously observed wide wavelength range, individual airglow emitters as well as correlations between them can be investigated in detail (cf. Noll et al. 2021, this session, for more information).</p><p>In this presentation we describe the properties and the calibration of this unique data set.</p>

scholarly journals The Diffuse Near- and Mid-Infrared Emission from the Galaxy

2001 ◽  
Vol 204 ◽  
pp. 35-46
Author(s):  
Martin Cohen
Keyword(s):  
Point Source ◽  
Surface Brightness ◽  
Near Infrared ◽  
Infrared Emission ◽  
Point Sources ◽  
Mid Infrared ◽  
Deep Point ◽  
Model Predictions ◽  
The Galaxy ◽  
Fundamental Stellar Parameters

Recognition of an isotropic cosmic near-infrared (NIR) and mid-infrared (MIR) background involves the removal of the zodiacal foreground (both scattered and reradiated), of the truly diffuse Galactic foreground (dominated by fluorescent bands of polcyclic aromatic hydrocarbons), and of resolved and unresolved Galactic point sources. I discuss model simulations of the near- and mid-infrared point source sky from which one can assess its particular contribution to the diffuse Galactic infrared foreground. I will also indicate the transitional stage which characterizes our knowledge of fundamental stellar parameters that are essential inputs to any such models. Using the latest version of the SKY model (Wainscoat et al. 1992; Cohen 1993; Cohen 1994; Cohen et al. 1994; Cohen 1995; Ruphy et al. 1997), I will demonstrate matches to deep point source counts for a variety of passbands and galactic latitudes, and will try to quantify the uncertainties achievable in model predictions of the integrated surface brightness due to the smearing of all these foreground point sources.

scholarly journals The European optical contribution to the James Webb Space Telescope

2018 ◽  
Vol 7 (6) ◽  
pp. 353-364
Author(s):  
Maurice te Plate ◽  
Brian O’Sullivan ◽  
Pierre Ferruit ◽  
David Lee ◽  
Martyn Wells ◽  
...  
Keyword(s):  
Near Infrared ◽  
Hubble Space Telescope ◽  
European Space Agency ◽  
Status Report ◽  
Mid Infrared ◽  
Space Telescope ◽  
International Partnership ◽  
Optical Science ◽  
Space Agency ◽  
James Webb Space Telescope

Abstract The James Webb Space Telescope (JWST) is frequently referred to as the follow-on mission to the Hubble Space Telescope (HST). The ‘Webb’ will be the biggest space telescope ever built and is expected to enable astounding new science. The observatory comprises a 6.5-m-diameter telescope with a segmented primary mirror and four high-performance optical science instruments. The JWST has mostly been optimized to work in the near- (0.6–5.0 μm) and mid-infrared (5.0–29 μm) wavelength regions. The project is a strong international partnership led by the National Aeronautics and Space Administration (NASA) with contributions from the European Space Agency (ESA) and the Canadian Space Agency (CSA). The observatory is currently scheduled for launch in early 2021 from Kourou, French Guyana, by an ESA-provided Ariane 5 rocket. This paper will focus on the European optical contribution to the mission, which mainly consists of two highly advanced optical science instruments: The multi-object near-infrared spectrograph (NIRSpec) and the mid-infrared instrument (MIRI). The opto-mechanical design considerations and the realization of both instruments will be described, and we will conclude with a short JWST project status report and future outlook.

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