Search Publications
On the Nature of the Radio Calibrator and Gamma-Ray Emitting NLS1 Galaxy 3C 286 and Its Multiwavelength Variability
Komossa, S.; Grupe, D.; Kraus, A. +1 more
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 radio emission, this makes 3C 286 one of the radio-loudest NLS1 galaxies known to date. 3C 286 is a…
Scientific Highlights of the AGILE Gamma-ray Mission
Tavani, Marco; Pittori, Carlotta; Vercellone, Stefano
The
X-ray Properties of Two Complementary Samples of Intermediate Seyfert Galaxies
Berton, Marco; Dalla Barba, Benedetta; Foschini, Luigi +2 more
We present the X-ray spectral analysis of two complementary sets of intermediate Seyfert galaxies (ISs). Analyzing X-ray data, we estimate the hydrogen abundance NH and test its connection with the [O III] luminosity acquired from optical observations. The results confirm the conclusions drawn in a previous study concerning the lack of a direct co…
3C 120 Disk/Corona vs. Jet Variability in X-rays
Fedorova, Elena; Del Popolo, Antonio
The 3C120 (Mrk 1506, UGC 03087, Mrk 9014) is a type 1 Seyfert (Sy1)/broad-line radio galaxy (BLRG) with intriguing variable jet activity featuring "dip" and "outburst" phases. Significant X-ray observational datasets have been collected for 3C120 by INTEGRAL, XMM-Newton, SWIFT, Suzaku, and other X-ray observational facilities. The overall X-ray sp…
Exploring the Fundamental Mechanism in Driving Highest-Velocity Ionized Outflows in Radio AGNs
Xue, Yongquan; Woo, Jong-Hak; He, Zhicheng +4 more
We investigate the ionized gas kinematics relationship with X-ray, radio and accreting properties using a sample of 348 nearby (z<0.4) SDSS-FIRST-X-ray detected AGNs. X-ray properties of our sample are obtained from XMM-Newton, Swift and Chandra observations. We unveil the ionized gas outflows in our sample manifested by the non-gravitational b…
Study of Intra-Day Flux Distributions of Blazars Using XMM-Newton Satellite
Gaur, Haritma; Wani, Kiran
We present a study of the flux distribution of a sample of 15 Intermediate and Low-energy peaked blazars using XMM-Newton observations in a total of 57 epochs on short-term timescales. We characterise the X-ray variability of all of the light curves using excess fractional variability amplitude and found that only 24 light curves in 7 sources are …
Project MOMO: Multiwavelength Observations and Modeling of OJ 287
Ciprini, S.; Komossa, S.; Gallo, L. C. +9 more
Our project MOMO (Multiwavelength observations and modeling of OJ 287) consists of dedicated, dense, long-term flux and spectroscopic monitoring, and deep follow-up observations of the blazar OJ 287 at >13 frequencies from the radio to the X-ray band since late 2015. In particular, we are using Swift to obtain optical-UV-X-ray spectral energy d…
A Long-Term Study of Ultraluminous X-ray Sources in NGC 891
Earley, Nicholas M.; Dwarkadas, Vikram V.; Cirillo, Victoria
We perform empirical fits to the Chandra and XMM-Newton spectra of three ultraluminous X-ray sources (ULXs) in the edge-on spiral galaxy NGC 891, monitoring the region over a 17-year time window. One of these sources was visible since the early 1990s with ROSAT and was observed multiple times with Chandra and XMM-Newton. Another was visible since …
Searching for Gamma-Ray Binaries in Multiwavelength Catalogs
Luque-Escamilla, Pedro L.; Martí, Josep
The number of gamma-ray binaries currently known is still so small that even a new finding represents a significant expansion of its population. We present a possible hunting strategy based on screening different catalogs to filter potential peculiar stars consistent with gamma-ray sources whose association at lower energies is not yet certain. So…