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Unified schemes of active galactic nuclei (AGN) require an obscuring dusty torus around the central engine. The compact sizes (only a few pc) determined in recent high-resolution observations require that the obscuring matter be clumpy and…

天体物理学 · 物理学 2011-02-11 Moshe Elitzur , Isaac Shlosman

The nearby spiral galaxy NGC 7331 was spectrally mapped from 5-38um using all modules of Spitzer's IRS spectrograph. A strong new dust emission feature, presumed due to PAHs, was discovered at 17.1um. The feature's intensity is nearly half…

We present a comparison of the gas and dust properties of the dense interstellar matter in six nearby star-forming regions (d<500 pc): rho Oph, Cha I, R CrA, IC 348, NGC 1333, and Orion. We measure from Chandra and XMM-Newton observations…

天体物理学 · 物理学 2009-11-10 MyHa Vuong , Thierry Montmerle , Nicolas Grosso , Eric Feigelson , Laurent Verstraete , Hideki Ozawa

We present preliminary results from high resolution (~ 0.05") adaptive optics observations of Cygnus A. The images show a bi-conic structure strongly suggestive of an obscuring torus around a quasar nucleus. A bright (K'=18.5) point source…

天体物理学 · 物理学 2016-01-27 Gabriela Canalizo , Claire Max , Robert Antonucci , David Whysong , Alan Stockton , Mark Lacy

The aim of this study is to constrain the dynamics, structure and feeding of the compact nucleous of NGC4418, and to reveal the nature of the main hidden power source: starburst or AGN. We obtained high spatial resolution observations of…

星系天体物理 · 物理学 2015-06-16 F. Costagliola , S. Aalto , K. Sakamoto , S. Martín , R. Beswick , S. Muller , H. -R. Klöckner

We present spectra of the nuclear regions of 50 nearby (D = 1 - 92 Mpc, median = 20 Mpc) galaxies of morphological types E to Sm. The spectra, obtained with the Gemini Near-IR Spectrograph on the Gemini North telescope, cover a wavelength…

I present a generalized power-law diagnostic that allows to identify the presence of active galactic nuclei (AGN) in infrared (IR) galaxies at z>1, down to flux densities at which the extragalactic IR background is mostly resolved. I derive…

宇宙学与河外天体物理 · 物理学 2015-06-15 Karina I. Caputi

We characterize the incidence of active galactic nuclei (AGNs) is 0.3 < z < 1 star-forming galaxies by applying multi-wavelength AGN diagnostics (X-ray, optical, mid-infrared, radio) to a sample of galaxies selected at 70-micron from the…

Obscuration of the innermost parts of active galactic nuclei (AGN) is observed in the majority of the population both in the nearby universe and at high redshift. However, the nature of the structures causing obscuration, especially in…

高能天体物理现象 · 物理学 2021-09-07 M. Baloković , S. E. Cabral , L. Brenneman , C. M. Urry

We observed with ALMA three deeply buried nuclei in two galaxies, NGC 4418 and Arp 220, at $\sim$0.2$''$ resolution over a total bandwidth of 67 GHz in $f_{\rm rest}$ = 215 - 697 GHz. Here we (1) introduce our program, (2) describe our data…

We investigate the contribution made by active galactic nuclei (AGN) to the high-redshift, luminous, submillimetre (submm) source population using deep (< 2 mJy/beam) Large Apex Bolometer Camera (LABOCA) 870 um observations within the…

宇宙学与河外天体物理 · 物理学 2011-10-31 R. M. Bielby , M. D. Hill , N. Metcalfe , T. Shanks

We present new groundbased 3 $\mu$m spectra of 14 young stellar objects with H_2O ice absorption bands. The broad absorption feature at 3.47 $\mu$m was detected toward all objects and its optical depth is correlated with the optical depth…

天体物理学 · 物理学 2009-10-31 T. Y. Brooke , K. Sellgren , T. R. Geballe

Using adaptive optics on Keck and the VLT in the H- and K-bands, we have begun a project to probe the dynamics and star formation around AGN on scales of 0.1arcsec. The stellar content of the nucleus is traced through the 2.29micron CO2-0…

天体物理学 · 物理学 2009-11-10 R. I. Davies , L. J. Tacconi , R. Genzel

The obscuration observed in active galactic nuclei (AGN) is mainly caused by dust and gas distributed in a torus-like structure surrounding the supermassive black hole (SMBH). However, properties of the obscuring torus of the AGN in X-ray…

星系天体物理 · 物理学 2021-06-09 X. Zhao , S. Marchesi , M. Ajello , D. Cole , Z. Hu , R. Silver , N. Torres-Albà

In the center of active galactic nuclei (AGN), the dusty torus absorb the radiation from the central engine and re-emit in mid-infrared (MIR). Observations have detected moderate anisotropy in the dust MIR emission, in the way that type 1…

高能天体物理现象 · 物理学 2015-06-23 Huan Yang , JunXian Wang , Teng Liu

Recent high resolution mapping of the circum-nuclear regions of Active Galactic Nuclei (AGN) has revealed the existence of geometrically thin nuclear disks, in general randomly oriented with respect to their galaxy hosts. These molecular…

We analyse different photometric and spectroscopic properties of active galactic nuclei (AGNs) and quasars (QSOs) selected by their mid-IR power-law and X-ray emission from the COSMOS survey. We use a set of star-forming galaxies as a…

星系天体物理 · 物理学 2020-03-25 Carlos Guillermo Bornancini , Diego García Lambas

NGC 1068 is a nearby Active Galactic Nucleus (AGN) of type 2, meaning that its accretion disk is hidden behind a large amount of foreground extinction. Observations at several wavelengths have revealed various disk-like structures around…

星系天体物理 · 物理学 2022-04-08 Pierre Vermot

We present a detailed study of the X-ray and optical spectra of the luminous Seyfert galaxy Mrk 1393, which revealed variable partial obscuration of the active nucleus. The X-ray spectra obtained by XMM-Newton and Swift show moderate…

宇宙学与河外天体物理 · 物理学 2009-11-13 T. G. Wang , H. Y. Zhou , D. Grupe , W. M. Yuan , X. B. Dong , H. L. Lu

The Two Micron All Sky Survey (2MASS) is finding previously unidentified, luminous red active galactic nuclei (AGN). This new sample has a space density similar to, or greater than, previously known AGN, suggesting that a large fraction of…

天体物理学 · 物理学 2009-11-07 Belinda J. Wilkes , Gary D. Schmidt , Roc M. Cutri , Himel Ghosh , Dean C. Hines , Brant Nelson , Paul Smith