scholarly journals A New Galactic Wolf-Rayet Star in Centaurus

2011 ◽  
Vol 2011 ◽  
pp. 1-6
Author(s):  
A. Roman-Lopes
Keyword(s):  
Near Infrared ◽  
Galactic Center ◽  
Absolute Magnitude ◽  
Infrared Emission ◽  
Point Sources ◽  
Cluster Candidate ◽  
Colour Distribution ◽  
Band Spectra ◽  
Rayet Star ◽  
Extended Emission

I communicate the detection of a new Galactic Wolf-Rayet star (WR60a) in Centaurus. The H- and K-band spectra of WR60a show strong carbon near-infrared emission lines, characteristic of Wolf-Rayet stars of the WC5-7 subtype. Adopting mean absolute magnitude MK and mean intrinsic (J-KS) and (H-KS) colours, it was found that WR60a suffers a mean visual extinction of 3.8±1.3 magnitudes, being located at a probable heliocentric distance of 5.2±0.8 Kpc, which for the related Galactic longitude (l=312) puts this star probably in the Carina-Sagittarius arm at about 5.9 kpc from the Galactic center. I searched for clusters in the vicinity of WR60a and in principle found no previously known clusters in a search radius region of several tens arcminutes. The detection of a well-isolated WR star induced us to seek for some still unknown cluster, somewhere in the vicinity of WR60a. From inspection of 5.8 μm and 8.0 μm Spitzer/IRAC GLIMPSE images of the region around the new WR star, strong mid-infrared extended emission at about 13.5 arcmin south-west of WR60a was found. The study of the H-KS colour distribution of point sources associated with the extended emission reveals the presence of a new Galactic cluster candidate probably formed by at least 85 stars.

scholarly journals A Comparison of Near Infrared Spectra of the Galactic Center He I Emission Line Sources and Early Type Mass Losing Stars

1996 ◽  
Vol 169 ◽  
pp. 225-230
Author(s):  
R. D. Blum ◽  
D. L. Depoy ◽  
K. Sellgren
Keyword(s):  
Emission Line ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Galactic Center ◽  
Early Type ◽  
Near Infrared Spectra ◽  
Wide Range ◽  
Comparison Stars ◽  
Band Spectra ◽  
Type Mass

We have obtained R ≈ 570 resolution K band spectra of eight sources in the Galactic Center, including four sources within the IRS 16 cluster, IRS 13, IRS 1W, and the compact He I emission line sources AF (also known as AHH) and AHH NW. We have also obtained R ≈ 570 H and K band spectra of nine galactic and LMC early–type mass–losing stars, including Ofpe/WN9 and WN stars. The spectra of both the Galactic Center sources and the comparison stars show a wide range of behavior in the He I (1.70 μm, 2.06 μm, 2.11 μm) and H I (Brackett series) lines. We find significantly larger He I equivalent widths in the AF source and two galactic early type mass losing stars than in any of the LMC stars. Several of the Galactic Center He I sources are found to have higher He I velocity widths than any of the galactic or LMC early type mass losing stars. At least one source, IRS 13, shows a strong red wing to the He I 2.06 μm emission.

scholarly journals The new infrared diffuse interstellar bands in the Galactic center

2013 ◽  
Vol 9 (S303) ◽  
pp. 75-77
Author(s):  
T. R. Geballe ◽  
F. Najarro ◽  
D. de la Fuente ◽  
D. F. Figer ◽  
A. J. Adamson ◽  
...  
Keyword(s):  
Near Infrared ◽  
Galactic Center ◽  
Overwhelming Majority ◽  
Specific Identification ◽  
General Consensus ◽  
Diffuse Interstellar Bands ◽  
Infrared Wavelengths ◽  
Band Spectra ◽  
The Universe ◽  
Absorption Features

The diffuse interstellar bands (DIBs) are a set of absorption features, some of which are broad (“diffuse”), that are formed in the diffuse ISM. Since their discovery nearly a century ago their numbers have increased to over 500. The strongest of these are known to be ubiquitous in the universe. There is general consensus that they are produced by large carbon-bearing molecules; however, no specific identification of any single DIB has survived scrutiny. The overwhelming majority of DIBs are at optical and very near infrared wavelengths. In 1990 two DIBs were identified in J-band spectra, at 1.18 μm and 1.31 μm by Joblin et al. (1990); until recently these were the longest wavelength examples known.

scholarly journals The Luminosity of the Central Parsec of the Galaxy

1989 ◽  
Vol 136 ◽  
pp. 423-436
Author(s):  
M. W. Werner ◽  
J. A. Davidson
Keyword(s):  
Near Infrared ◽  
Galactic Center ◽  
Thermal Emission ◽  
Large Magellanic Cloud ◽  
Infrared Emission ◽  
Infrared Observations ◽  
The Galaxy ◽  
Infrared Wavelengths ◽  
Central Parsec ◽  
30 Doradus

The luminosity of the central 5 pc of the Galaxy -encompassing the inner regions of the rotating ring of dust and gas which surrounds the galactic center - emerges primarily at infrared wavelengths in the form of thermal emission from heated dust. The nature and location of the sources which heat the dust can be inferred from the spatial and temperature distribution of the thermal infrared emission (λ>20um), from studies of the ionized gas in this region, and from direct imaging in the near infrared. These observations show that the principal heating sources within this 5-pc region are concentrated within the central parsec of the Galaxy and indicate that the luminosity of these sources is within a factor of two of 107 LO. The near-infrared observations of the compact sources at the galactic center do not reveal a single dominant source but suggest instead that the several components of the IRS-16 complex, taken together, may contribute the bulk of the luminosity; however, the data also permit a single object to dominate the energetics of this region. We draw attention to the striking morphological similarities between the galactic center and the innermost regions of the 30 Doradus nebula in the Large Magellanic Cloud and speculate that the luminosity sources in the galactic center may resemble the early-type supergiants in 30 Doradus.

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 NIR counterparts to ULXs (III): completing the photometric survey and selected spectroscopic results★

2020 ◽  
Vol 497 (1) ◽  
pp. 917-932 ◽  
Author(s):  
K M López ◽  
M Heida ◽  
P G Jonker ◽  
M A P Torres ◽  
T P Roberts ◽  
...  
Keyword(s):  
Binary Systems ◽  
Near Infrared ◽  
Absolute Magnitude ◽  
Stellar Clusters ◽  
Stellar Spectra ◽  
Stellar Cluster ◽  
Cluster Candidate ◽  
Spatially Extended ◽  
Binary Evolution

ABSTRACT We present results from the remaining sources in our search for near-infrared (NIR) candidate counterparts to ultraluminous X-ray sources (ULXs) within ≃10 Mpc. We observed 23 ULXs in 15 galaxies and detected NIR candidate counterparts to 6 of them. Two of these have an absolute magnitude consistent with a single red supergiant (RSG). Three counterparts are too bright for an RSG and spatially extended, and thus we classify them as stellar clusters. The other candidate is too faint for an RSG. Additionally, we present the results of our NIR spectroscopic follow-up of five sources: four originally classified as RSG and one as a stellar cluster on the basis of previous photometry. The stellar cluster candidate is actually a nebula. Of the four RSG candidates, one source has a broad H α emission line redshifted by ∼z = 1, making it a background active galactic nucleus (AGN). Two other sources show stellar spectra consistent with them being RSGs. The final RSG candidate is too faint to classify, but does not show strong (nebular) emission lines in its spectrum. After our search for NIR counterparts to 113 ULXs, where we detected a candidate counterpart for 38 ULXs, we have spectroscopically confirmed the nature of 12: 5 sources are nebulae, 1 source is not classified, 1 source is an AGN, and 5 are RSGs. These possible five ULX–RSG binary systems would constitute ${\simeq} (4 \pm 2){{\ \rm per\ cent}}$ of the observed ULXs, a fraction almost four times larger than what was predicted by binary evolution simulations.

scholarly journals Amphiprotism-Coupled Near-Infrared Emission in Extended Pyrazinacenes Containing Seven Linearly Fused Pyrazine Units

2019 ◽  
Vol 141 (50) ◽  
pp. 19570-19574 ◽  
Author(s):  
Gary J. Richards ◽  
Aël Cador ◽  
Shinji Yamada ◽  
Anna Middleton ◽  
Whitney A. Webre ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Emission ◽  
Near Infrared Emission

Broadband near-infrared emission of K3ScF6:Cr3+ phosphors for night vision imaging system sources

2021 ◽  
Vol 417 ◽  
pp. 129271
Author(s):  
Haojun Yu ◽  
Jian Chen ◽  
Ruiyu Mi ◽  
Juyu Yang ◽  
Yan-gai Liu
Keyword(s):  
Near Infrared ◽  
Imaging System ◽  
Infrared Emission ◽  
Night Vision ◽  
Near Infrared Emission

Broadband near infrared emission of Er3+/Yb3+ co-doped fluorotellurite glass

2021 ◽  
Vol 866 ◽  
pp. 158568
Author(s):  
Jiaming Liu ◽  
Xin Huang ◽  
Heng Pan ◽  
Xu Zhang ◽  
Xiujie Fang ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Emission ◽  
Near Infrared Emission ◽  
Co Doped

Ab Initio Two-sites Occupancy and Broadband Near-Infrared Emission of Cr3+ in Li2MgZrO4

2021 ◽  
Author(s):  
Xue Zhou ◽  
Jinmeng Xiang ◽  
Jiming Zheng ◽  
Xiaoqi Zhao ◽  
Hao Suo ◽  
...  
Keyword(s):  
Plant Growth ◽  
Ab Initio ◽  
Light Source ◽  
Near Infrared ◽  
Broad Band ◽  
Infrared Emission ◽  
Night Vision ◽  
Light Emitting ◽  
Non Destructive ◽  
Near Infrared Emission

Near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) light source have great potential in non-destructive detection, promoting plant growth and night vision applications, while the discovery of a broad-band NIR phosphor still...

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