Zobrazeno 1 - 10
of 733
pro vyhledávání: '"Grupe D"'
Autor:
Komossa, S., Grupe, D., Marziani, P., Popovic, L. C., Marceta-Mandic, S., Bon, E., Ilic, D., Kovacevic, A. B., Kraus, A., Haiman, Z., Petrecca, V., De Cicco, D., Dimitrijevic, M. S., Sreckovic, V. A., Dojcinovic, J. Kovacevic, Pannikkote, M., Bon, N., Gupta, K. K., Iacob, F.
The extremes of Active Galactic Nuclei (AGN) variability offer valuable new insights into the drivers and physics of AGN. We discuss some of the most extreme cases of AGN variability; the highest amplitudes, deep minima states, extreme spectral state
Externí odkaz:
http://arxiv.org/abs/2408.00089
A well-known calibrator source in radio astronomy, 3C 286 ($z=0.85$), is a compact steep-spectrum (CSS) radio source and spectroscopically classified as a narrow-line Seyfert 1 (NLS1) galaxy. It is also known for its damped Ly$\alpha$ system from an
Externí odkaz:
http://arxiv.org/abs/2407.18475
The quasar 3C 286, a well-known calibrator source in radio astronomy, was found to exhibit exceptional multiwavelength properties. Its rich and complex optical emission-line spectrum revealed its narrow-line Seyfert 1 (NLS1) nature. Given its strong
Externí odkaz:
http://arxiv.org/abs/2406.08312
Autor:
Buhariwalla, Margaret Z., Gallo, L. C., Mao, J., Jiang, J., Pothier-Bogoslowski, L. K., Järvelä, E., Komossa, S., Grupe, D.
Previous X-ray works on Mrk 1239 have revealed a complex Narrow Line Seyfert 1 (NLS1) that exhibits substantial absorption and strong emission from both collisional (CIE) and photoionized (PIE) plasmas. Here, we report on deep-pointed observations wi
Externí odkaz:
http://arxiv.org/abs/2405.08785
Autor:
Ochmann, M. W., Kollatschny, W., Probst, M. A., Romero-Colmenero, E., Buckley, D. A. H., Chelouche, D., Chini, R., Grupe, D., Haas, M., Kaspi, S., Komossa, S., Parker, M. L., Santos-Lleo, M., Schartel, N., Famula, P.
Publikováno v:
A&A 686, A17 (2024)
NGC 1566 is known for exhibiting recurrent outbursts, which are accompanied by changes in spectral type. The most recent transient event occurred from 2017 to 2019 and was reported to be accompanied by a change in Seyfert classification from Seyfert
Externí odkaz:
http://arxiv.org/abs/2402.12054
Autor:
Xu, D. W., Komossa, S., Grupe, D., Wang, J., Xin, L. P., Han, X. H., Wei, J. Y., Bai, J. Y., Bon, E., Cangemi, F., Cordier, B., Dennefeld, M., Gallo, L. C., Kollatschny, W., Kong, De-Feng, Ochmann, M. W., Qiu, Y. L., Schartel, N.
We discuss applications of the study of the new and barely explored class of changing-look (CL) narrow-line Seyfert 1 (NLS1) galaxies and comment on their detection with the space mission SVOM (Space Variable Objects Monitor). We highlight the case o
Externí odkaz:
http://arxiv.org/abs/2401.10600
Autor:
Komossa, S., Kraus, A., Grupe, D., Gonzalez, A. G., Gurwell, M. A., Gallo, L. C., Liu, F. K., Myserlis, I., Krichbaum, T. P., Laine, S., Bach, U., Gomez, J. L., Parker, M. L., Yao, S., Berton, M.
Based on our dedicated Swift monitoring program, MOMO, OJ 287 is one of the best-monitored blazars in the X-ray--UV--optical regime. Here, we report results from our accompanying, dense, multi-frequency (1.4--44 GHz) radio monitoring of OJ 287 betwee
Externí odkaz:
http://arxiv.org/abs/2302.11486
Autor:
Komossa, S., Grupe, D., Kraus, A., Gurwell, M. A., Haiman, Z., Liu, F. K., Tchekhovskoy, A., Gallo, L. C., Berton, M., Blandford, R., Gomez, J. L., Gonzalez, A. G.
The project MOMO (Multiwavelength Observations and Modelling of OJ 287) was set up to test predictions of binary supermassive black hole (SMBH) scenarios and to understand disk-jet physics of the blazar OJ 287. After a correction, the precessing bina
Externí odkaz:
http://arxiv.org/abs/2302.11646
Autor:
Buhariwalla, Margaret Z., Gallo, Luigi C., Mao, J., Komossa, S., Jiang, J., Gonzalez, A, Grupe, D.
Mrk 1239 is a highly polarized NLS1 in the optical band, whose $0.3-3$ keV spectrum has remained remarkably consistent over more than two decades of observation. Previous analysis of this object suggested that the soft X-ray band was dominated by emi
Externí odkaz:
http://arxiv.org/abs/2301.06559
Autor:
Komossa, S., Grupe, D.
We present a review of the topics of X-ray stellar tidal disruption events (TDEs) and changing-look active galactic nuclei (AGN). Stars approaching a supermassive black hole (SMBH) can be tidally disrupted and accreted. TDEs were first discovered in
Externí odkaz:
http://arxiv.org/abs/2212.10331