Zobrazeno 1 - 10
of 5 250
pro vyhledávání: '"Grupe, A"'
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:
Green, Kaylie S., Gallagher, Sarah C., Leighly, Karen M., Choi, Hyunseop, Grupe, Dirk, Terndrup, Donald M., Richards, Gordon T., Komossa, S.
Publikováno v:
2023, ApJ, 953, 186
Broad Absorption Line Quasars (BALQs) are actively accreting supermassive black holes that have strong outflows characterized by broad absorption lines in their rest-UV spectra. Variability in these absorption lines occurs over months to years depend
Externí odkaz:
http://arxiv.org/abs/2405.06027
We report on follow-up observations of the Seyfert 1.9 galaxy IC 3599 with the NASA Neil Gehrels Swift mission. The detection of a second X-ray outburst in 2010 by Swift after the first discovery of a bright X-ray outburst in 1990 by ROSAT led to the
Externí odkaz:
http://arxiv.org/abs/2404.19107
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:
Green, Matthew J., Hermes, J. J., Barlow, Brad N., Marsh, T. R., Pelisoli, Ingrid, Gänsicke, Boris T., Kaiser, Ben C., Romero, Alejandra, Amaral, Larissa Antunes, Corcoran, Kyle, Grupe, Dirk, Kennedy, Mark R., Kepler, S. O., Munday, James, Ashley, R. P., Baran, Andrzej S., Breedt, Elmé, Brown, Alex J., Dhillon, V. S., Dyer, Martin J., Kerry, Paul, King, George W., Littlefair, S. P., Parsons, Steven G., Sahman, David I.
AM CVn-type systems are ultracompact, helium-accreting binary systems which are evolutionarily linked to the progenitors of thermonuclear supernovae and are expected to be strong Galactic sources of gravitational waves detectable to upcoming space-ba
Externí odkaz:
http://arxiv.org/abs/2311.01255
Autor:
Hu, Zhensong, Su, Yuanyuan, Li, Zhiyuan, Hess, Kelley M., Kraft, Ralph P., Forman, William R., Nulsen, Paul E. J., Sridhar, Sarrvesh S., Stroe, Andra, Baek, Junhyun, Chung, Aeree, Grupe, Dirk, Chen, Hao, Irwin, Jimmy A., Jones, Christine, Randall, Scott W., Roediger, Elke
To understand the formation and growth of supermassive black holes (SMBHs) and their co-evolution with host galaxies, it is essential to know the impact of environment on the activity of active galactic nuclei (AGN). We present new Chandra X-ray obse
Externí odkaz:
http://arxiv.org/abs/2308.12565