The warped disk of Centaurus A in the near-infrared

1993 ◽  
Vol 412 ◽  
pp. 550 ◽  
Author(s):  
A. C. Quillen ◽  
James R. Graham ◽  
Jay A. Frogel
Keyword(s):  
2020 ◽  
Vol 72 (5) ◽  
Author(s):  
Risako Katayama ◽  
Hidehiro Kaneda ◽  
Takuma Kokusho ◽  
Kumiko Morihana ◽  
Toyoaki Suzuki ◽  
...  

Abstract Centaurus A (Cen A) is one of the most famous galaxies hosting an active galactic nucleus (AGN), where the interaction between AGN activities and surrounding interstellar and intergalactic media has been investigated. Recent studies reported detections of Hα emission from clouds in the galactic halo toward the northeast and southwest of the nucleus of Cen A, suggesting that AGN jets may have triggered star formation there. We performed near-infrared line mapping of Cen A with the IRSF 1.4 m telescope, using the narrow-band filter tuned for Paβ, from which we find that Paβ emission is not detected significantly from either of the northeast or southwest regions. The upper limit of the Paβ/Hα ratio in the northeast region is compatible with that expected for a typical H ii region, in line with the scenario that AGNs have triggered star formation there. On the other hand, the upper limit of Paβ/Hα in the southwest region is significantly lower than that expected for a typical H ii region. A possible explanation of the low Paβ/Hα ratio in the southwest region is the scattering of Hα and Paβ photons from the center of Cen A by dust grains in the halo clouds. From the upper limit of Paβ/Hα in the southwest region, we obtain constraints on the dust size distribution, which is found to be compatible with those seen in the interstellar medium of our Galaxy.


2005 ◽  
Vol 130 (2) ◽  
pp. 406-417 ◽  
Author(s):  
Julia D. Silge ◽  
Karl Gebhardt ◽  
Marcel Bergmann ◽  
Douglas Richstone

1987 ◽  
Vol 127 ◽  
pp. 427-428
Author(s):  
W B Sparks ◽  
J. Bailey ◽  
J C Hough ◽  
C. Brindle ◽  
D J Axon

Near infrared polarimetry of Centaurus A and IC5063 has revealed the existence of a steep spectrum highly polarized source in the nuclei of both galaxies. The position angle of polarization is perpendicular to the radio position angle. We interpret this polarized emission as synchrotron radiation. This, together with a luminosity of 5 × 1041erg s-1, suggests the galaxies are low luminosity blazars and that such nuclei may be common in elliptical galaxies.


2020 ◽  
Vol 72 (5) ◽  
Author(s):  
Risako Katayama ◽  
Hidehiro Kaneda ◽  
Takuma Kokusho ◽  
Kumiko Morihana ◽  
Toyoaki Suzuki ◽  
...  

1992 ◽  
Vol 10 (2) ◽  
pp. 104-106 ◽  
Author(s):  
Vikki Meadows ◽  
David Allen

AbstractWe present near-infrared images and spectra of the peculiar radio galaxy Centaurus A. The images reveal extended emission regions at the longer wavelengths and show colours characteristic of reddened starlight. We believe we are seeing stars within the warped disc of Cen A, which are obscured in the optical by dust. Both images and spectra indicate the presence of a compact core, whose colours are much redder than those of the surrounding stars. In the spectrum of the core, detections have been made of [Fe II] 1.644 μm, H2 2.122 μm and Br γ. These lines appear to peak on the nucleus and their presence and width suggest starburst activity.


Nanoscale ◽  
2020 ◽  
Vol 12 (14) ◽  
pp. 7875-7887 ◽  
Author(s):  
Ying Lan ◽  
Xiaohui Zhu ◽  
Ming Tang ◽  
Yihan Wu ◽  
Jing Zhang ◽  
...  

A near-infrared (NIR) activated theranostic nanoplatform based on upconversion nanoparticles (UCNPs) is developed in order to overcome the hypoxia-associated resistance in photodynamic therapy by photo-release of NO upon NIR illumination.


2020 ◽  
Vol 56 (43) ◽  
pp. 5819-5822
Author(s):  
Jing Zheng ◽  
Yongzhuo Liu ◽  
Fengling Song ◽  
Long Jiao ◽  
Yingnan Wu ◽  
...  

In this study, a near-infrared (NIR) theranostic photosensitizer was developed based on a heptamethine aminocyanine dye with a long-lived triplet state.


2020 ◽  
Vol 48 (6) ◽  
pp. 2657-2667
Author(s):  
Felipe Montecinos-Franjola ◽  
John Y. Lin ◽  
Erik A. Rodriguez

Noninvasive fluorescent imaging requires far-red and near-infrared fluorescent proteins for deeper imaging. Near-infrared light penetrates biological tissue with blood vessels due to low absorbance, scattering, and reflection of light and has a greater signal-to-noise due to less autofluorescence. Far-red and near-infrared fluorescent proteins absorb light >600 nm to expand the color palette for imaging multiple biosensors and noninvasive in vivo imaging. The ideal fluorescent proteins are bright, photobleach minimally, express well in the desired cells, do not oligomerize, and generate or incorporate exogenous fluorophores efficiently. Coral-derived red fluorescent proteins require oxygen for fluorophore formation and release two hydrogen peroxide molecules. New fluorescent proteins based on phytochrome and phycobiliproteins use biliverdin IXα as fluorophores, do not require oxygen for maturation to image anaerobic organisms and tumor core, and do not generate hydrogen peroxide. The small Ultra-Red Fluorescent Protein (smURFP) was evolved from a cyanobacterial phycobiliprotein to covalently attach biliverdin as an exogenous fluorophore. The small Ultra-Red Fluorescent Protein is biophysically as bright as the enhanced green fluorescent protein, is exceptionally photostable, used for biosensor development, and visible in living mice. Novel applications of smURFP include in vitro protein diagnostics with attomolar (10−18 M) sensitivity, encapsulation in viral particles, and fluorescent protein nanoparticles. However, the availability of biliverdin limits the fluorescence of biliverdin-attaching fluorescent proteins; hence, extra biliverdin is needed to enhance brightness. New methods for improved biliverdin bioavailability are necessary to develop improved bright far-red and near-infrared fluorescent proteins for noninvasive imaging in vivo.


Sign in / Sign up

Export Citation Format

Share Document