Results 41 to 50 of about 89,220 (323)

Discovery of an Mg ii Changing-look Active Galactic Nucleus and Its Implications for a Unification Sequence of Changing-look Active Galactic Nuclei [PDF]

Astrophysical Journal, 2019
Changing look (CL) is a rare phenomenon of active galactic nuclei (AGNs) that exhibit emerging or disappearing broad lines accompanied by continuum variations on astrophysically short timescales (≲1 yr to a few decades). While previous studies have found
H. Guo 郭, Mouyuan Sun, Xin Liu, Ting-gui Wang, M. Kong, Shu Wang, Zhenfeng Sheng, Zhicheng He   +7 more
semanticscholar   +1 more source

A quasi-periodic oscillation in the blazar J1359+4011 [PDF]

, 2013
The OVRO 40-m telescope has been monitoring the 15 GHz radio flux density of over 1200 blazars since 2008. The 15 GHz light curve of the flat spectrum radio quasar J1359+4011 shows a strong and persistent quasi-periodic oscillation. The time-scale of the
Hovatta, T., King, O. G., Max-Moerbeck, W., Meier, D. L., Pearson, T. J., Readhead, A. C. S., Reeves, R., Richards, J. L., Shepherd, M. C.   +8 more
core   +4 more sources

Modeling Nearby Low-Luminosity Active-Galactic-Nucleus Jet Images at All VLBI Scales

Galaxies, 2022
Relativistic jets from nearby low-luminosity active-galactic-nuclei (LLAGN) were observed by Very-Long Baseline Interferometry (VLBI) across many orders of magnitude in space, from milliparsec to sub-parsec scales, and from the jet base in the vicinity ...
Hung-Yi Pu, Keiichi Asada, Masanori Nakamura   +2 more
doaj   +1 more source

Galaxies hosting an active galactic nucleus: a view from the CALIFA survey [PDF]

, 2019
We study the presence of optically-selected Active Galactic Nuclei (AGNs) within a sample of 867 galaxies extracted from the extended {\it Calar-Alto Legacy Integral Field spectroscopy Area} (eCALIFA) spanning all morphological classes.
E. Lacerda, S. S'anchez, R. Cid Fernandes, C. López-Cobá, C. Espinosa-Ponce, L. Galbany   +5 more
semanticscholar   +1 more source

Spectropolarimetry of the changing-look active galactic nucleus Mrk 1018 [PDF]

Astronomy & Astrophysics, 2020
We have obtained new spectropolarimetric observations at visible wavelengths of the changing-look active galactic nucleus (AGN) Mrk 1018. The AGN direct spectrum shows an extremely weak continuum with faint broad Hβ and Hα emission lines. Both lines can be fit with a single very broad emission line component of full width at half maximum FWHM ≃ 7200 km
Hutsemékers, D., Agís González, B., Marin, F., Sluse, D.   +3 more
openaire   +4 more sources

A Diverse Population of z ∼ 2 ULIRGs Revealed by JWST Imaging

The Astrophysical Journal, 2023
Four ultraluminous infrared galaxies (ULIRGs) observed with JWST/NIRcam in the Cosmos Evolution Early Release Science program offer an unbiased preview of the z ∼ 2 ULIRG population.
J.-S. Huang, Zi-Jian Li, Cheng Cheng, Meicun Hou, Haojing Yan, S. P. Willner, Y.-S. Dai, X. Z. Zheng, J. Pan, D. Rigopoulou, T. Wang, Zhiyuan Li, Piaoran Liang, A. Esamdin, G. G. Fazio   +14 more
doaj   +1 more source

THE MAN BEHIND THE CURTAIN: X-RAYS DRIVE THE UV THROUGH NIR VARIABILITY IN THE 2013 ACTIVE GALACTIC NUCLEUS OUTBURST IN NGC 2617 [PDF]

, 2013
After the All-Sky Automated Survey for SuperNovae discovered a significant brightening of the inner region of NGC 2617, we began a ∼70 day photometric and spectroscopic monitoring campaign from the X-ray through near-infrared (NIR) wavelengths. We report
B. Shappee, J. Prieto, D. Grupe, C. Kochanek, K. Stanek, G. D. Rosa, S. Mathur, Y. Zu, B. Peterson, R. Pogge, S. Komossa, M. Im, J. Jencson, T. Holoien, U. Basu, J. Beacom, D. Szczygieł, J. Brimacombe, S. Adams, A. Campillay, Changsu Choi, C. Contreras, M. Dietrich, M. Dubberley, M. Elphick, S. Foale, M. Giustini, C. González, E. Hawkins, D. Howell, D. Howell, E. Hsiao, M. Koss, K. Leighly, N. Morrell, D. Mudd, D. Mullins, J. Nugent, J. Parrent, M. Phillips, G. Pojmański, W. Rosing, R. Ross, D. Sand, D. Terndrup, S. Valenti, S. Valenti, Z. Walker, Y. Yoon   +48 more
semanticscholar   +1 more source

Atomic gas fractions in active galactic nucleus host galaxies [PDF]

Monthly notices of the Royal Astronomical Society, 2018
The feedback from an active galactic nucleus (AGN) is frequently invoked as a mechanism through which gas can be heated or removed from a galaxy. However, gas fraction measurements in AGN hosts have yielded mixed support for this scenario.
S. Ellison, T. Brown, B. Catinella, L. Cortese   +3 more
semanticscholar   +1 more source

NGC 1808: active galactic nucleus or starburst? [PDF]

Monthly Notices of the Royal Astronomical Society, 1992
We present optical and near-infrared images, together with long-slit spectra at red wavelengths, of NGC 1808. The complex morphology of hotspots seen at short wavelengths may be the result of dust obscuration. Our data (namely the equivalent width of the Ca II triplet and broad-band colours) suggest the presence of red supergiants, associated with a ...
Martin Ward, Duncan A. Forbes, Catherine Boisson   +2 more
openaire   +2 more sources

Powerful mechanical-driven outflows in the central parsecs of the low-luminosity active galactic nucleus ESO 428-G14 [PDF]

Monthly Notices of the Royal Astronomical Society: Letters, 2018
Low-luminosity Active Galactic Nuclei (LLAGNs) are characterized for low-radiative efficiency, much less than one percent of their Eddington limit. Nevertheless, their main energy release may be mechanical, opposite to powerful AGN classes like Seyfert ...
D. May, A. Rodríguez-Ardila, A. Prieto, J. A. Fern'andez-Ontiveros, Y. Diaz, X. Mazzalay   +5 more
semanticscholar   +1 more source