scholarly journals Project MOMO: Multiwavelength Observations and Modeling of OJ 287

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 261
Author(s):  
S. Komossa ◽  
D. Grupe ◽  
A. Kraus ◽  
L. C. Gallo ◽  
A. G. Gonzalez ◽  
...  
Keyword(s):  
Black Hole ◽  
Broad Band ◽  
Spectral Energy ◽  
X Rays ◽  
X Ray ◽  
Binary Black Hole ◽  
Accretion Physics ◽  
Radio Measurements ◽  
Multiwavelength Observations

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 distributions (SEDs) and the Effelsberg telescope to obtain radio measurements between 2 and 40 GHz. MOMO is the densest long-term monitoring of OJ 287 involving X-rays and broad-band SEDs. The theoretical part of the project aims at understanding jet and accretion physics of the blazar central engine in general and the supermassive binary black hole scenario in particular. Results are presented in a sequence of publications and so far included: detection and detailed analysis of the bright 2016/17 and 2020 outbursts and the long-term light curve; Swift, XMM, and NuSTAR spectroscopy of the 2020 outburst around maximum; and interpretation of selected events in the context of the binary black hole scenario of OJ 287 (papers I–IV). Here, we provide a description of the project MOMO, a summary of previous results, the latest results, and we discuss future prospects.

scholarly journals The 2020 April–June super-outburst of OJ 287 and its long-term multiwavelength light curve with Swift: binary supermassive black hole and jet activity

2020 ◽  
Vol 498 (1) ◽  
pp. L35-L39 ◽  
Author(s):  
S Komossa ◽  
D Grupe ◽  
M L Parker ◽  
M J Valtonen ◽  
J L Gómez ◽  
...  
Keyword(s):  
Black Hole ◽  
Light Curve ◽  
X Rays ◽  
X Ray ◽  
Binary Black Hole ◽  
Energy Part ◽  
Inverse Compton ◽  
Hole Model ◽  
Multiple Episodes

ABSTRACT We report detection of a very bright X-ray–UV–optical outburst of OJ 287 in 2020 April–June, the second brightest since the beginning of our Swift multiyear monitoring in late 2015. It is shown that the outburst is predominantly powered by jet emission. Optical–UV–X-rays are closely correlated, and the low-energy part of the XMM–Newton spectrum displays an exceptionally soft emission component consistent with a synchrotron origin. A much harder X-ray power-law component (Γx = 2.4, still relatively steep when compared to expectations from inverse Compton models) is detected out to 70 keV by NuSTAR. We find evidence for reprocessing around the Fe region, consistent with an absorption line. If confirmed, it implies matter in outflow at ∼0.1c. The multiyear Swift light curve shows multiple episodes of flaring or dipping with a total amplitude of variability of a factor of 10 in X-rays, and 15 in the optical–UV. The 2020 outburst observations are consistent with an after-flare predicted by the binary black hole model of OJ 287, where the disc impact of the secondary black hole triggers time-delayed accretion and jet activity of the primary black hole.

scholarly journals Accretion-outflow connection in the outliers of the “universal” radio/X-ray correlation

2010 ◽  
Vol 6 (S275) ◽  
pp. 255-259
Author(s):  
M. Coriat ◽  
S. Corbel ◽  
L. Prat ◽  
J. C. A. Miller-Jones ◽  
D. Cseh ◽  
...  
Keyword(s):  
Black Hole ◽  
Compact Objects ◽  
X Rays ◽  
X Ray ◽  
Black Hole Candidate ◽  
Long Term Study ◽  
Hard State ◽  
Universal Correlation ◽  
X Ray Binaries

AbstractIn recent years, numerous efforts have been devoted to unravel the connection between accretion flow and jets in accreting compact objects. Here we report new constraints on these issues, through the long term study of the radio and X-ray behaviour of the black hole candidate H 1743–322. This source is known to be one of the “outliers” of the universal radio/X-ray correlation, i.e. a group of stellar mass accreting black holes displaying fainter radio emission for a given X-ray luminosity, than expected from the correlation. In this work we find, at high X-ray luminosity in the hard state, a tight radio/X-ray correlation with an unusual steep slope of b = 1.38 ± 0.03. This correlation then breaks below ~5 × 10−3LEdd (M/10M⊙)−1 in X-rays and becomes shallower. When compared with radio/X-ray data from other black hole X-ray binaries, we see that the deviant points of H 1743–322 join the universal correlation and seem to follow it at low luminosity. Based on these results, we investigate several hypotheses that could explain both the b ~ 1.4 slope and the transition toward the universal correlation.

scholarly journals The first broad-band X-ray view of the narrow-line Seyfert 1 Ton S180

2020 ◽  
Vol 497 (2) ◽  
pp. 2352-2370 ◽  
Author(s):  
G A Matzeu ◽  
E Nardini ◽  
M L Parker ◽  
J N Reeves ◽  
V Braito ◽  
...  
Keyword(s):  
Thermal Emission ◽  
Spectral Energy Distribution ◽  
Broad Band ◽  
Outer Part ◽  
Spectral Energy ◽  
X Rays ◽  
Narrow Line ◽  
X Ray ◽  
Extreme Uv ◽  
Reflection Grating

ABSTRACT We present joint XMM–Newton and NuSTAR observations of the ‘bare’ narrow-line Seyfert 1 Ton S180 (z = 0.062), carried out in 2016 and providing the first hard X-ray view of this luminous galaxy. We find that the 0.4–30 keV band cannot be self-consistently reproduced by relativistic reflection models, which fail to account simultaneously for the soft and hard X-ray emission. The smooth soft excess prefers extreme blurring parameters, confirmed by the nearly featureless nature of the Reflection Grating Spectrometer (RGS) spectrum, while the moderately broad Fe K line and the modest hard excess above 10 keV appear to arise in a milder gravity regime. By allowing a different origin of the soft excess, the broad-band X-ray spectrum and overall spectral energy distribution (SED) are well explained by a combination of (a) direct thermal emission from the accretion disc, dominating from the optical to the far/extreme UV; (b) Comptonization of seed disc photons by a warm (kTe ∼ 0.3 keV) and optically thick (τ ∼ 10) corona, mostly contributing to the soft X-rays; (c) Comptonization by a standard hot ($kT_{\rm \mathrm{ e}}\gtrsim 100$ keV) and optically thin (τ < 0.5) corona, responsible for the primary X-ray continuum; and (d) reflection from the mid/outer part of the disc. The two coronae are suggested to be rather compact, with $R_{\rm hot}\lesssim R_{\rm warm}\lesssim 10\, r_{\rm g}$. Our SED analysis implies that Ton S180 accretes at super-Eddington rates. This is a key condition for the launch of a wind, marginal (i.e. 3.1σ significance) evidence of which is indeed found in the RGS spectrum.

scholarly journals X-ray spectral diagnostics of activity in massive stars

2010 ◽  
Vol 6 (S272) ◽  
pp. 348-353 ◽  
Author(s):  
David H. Cohen ◽  
Emma E. Wollman ◽  
Maurice A. Leutenegger
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Broad Band ◽  
Variable Structure ◽  
Spectral Energy ◽  
X Rays ◽  
X Ray ◽  
Spectral Diagnostics ◽  
Loss Rates

AbstractX-rays give direct evidence of instabilities, time-variable structure, and shock heating in the winds of O stars. The observed broad X-ray emission lines provide information about the kinematics of shock-heated wind plasma, enabling us to test wind-shock models. And their shapes provide information about wind absorption, and thus about the wind mass-loss rates. Mass-loss rates determined from X-ray line profiles are not sensitive to density-squared clumping effects, and indicate mass-loss rate reductions of factors of 3 to 6 over traditional diagnostics that suffer from density-squared effects. Broad-band X-ray spectral energy distributions also provide mass-loss rate information via soft X-ray absorption signatures. In some cases, the degree of wind absorption is so high, that the hardening of the X-ray SED can be quite significant. We discuss these results as applied to the early O stars ζ Pup (O4 If), 9 Sgr (O4 V((f))), and HD 93129A (O2 If*).

scholarly journals Advection-Dominated Accretion, Jets, and the Spectral Energy Distribution of LINERs

2009 ◽  
Vol 5 (S267) ◽  
pp. 313-318
Author(s):  
Rodrigo S. Nemmen ◽  
Thaisa Storchi-Bergmann ◽  
Michael Eracleous ◽  
Feng Yuan
Keyword(s):  
Mass Loss Rate ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
X Rays ◽  
X Ray ◽  
Accretion Flow ◽  
Central Engine ◽  
Relativistic Jet ◽  
Recent Compilation ◽  
Accretion Physics

AbstractLow-luminosity active galactic nuclei (LLAGNs) represent the bulk of the AGN population in the present-day universe and they trace low-level accreting supermassive black holes. The observational properties of LLAGNs suggest that their central engines are intrinsically different from those of more luminous AGNs. It has been suggested that accretion in LLAGNs occurs via an advection-dominated accretion flow (ADAF) associated with strong jets. In order to probe the accretion physics in LLAGNs as a class, we model the multiwavelength spectral energy distributions (SEDs) of 24 LINERs (taken from a recent compilation by Eracleous et al.) with a coupled accretion-jet model. The accretion flow is modeled as an inner ADAF outside of which there is a truncated standard thin disk. These SEDs include radio, near-IR to near-UV HST data, and Chandra X-ray data. We find that the radio emission is severely underpredicted by ADAF models but can be explained by the relativistic jet. The origin of the X-ray radiation in most sources can be explained by three distinct scenarios: the X-rays can be dominated by emission from the ADAF, the jet, or from both components contributing at similar levels. From the model fits, we estimate important parameters of the central engine of LINERs, such as the mass accretion rate — relevant for studies of the feeding of AGNs — and the mass-loss rate in the jet and the jet power — relevant for studies of the kinetic feedback from jets.

scholarly journals A new hard X-ray-selected sample of extreme high-energy peaked BL Lac objects and their TeV gamma-ray properties

2019 ◽  
Vol 486 (2) ◽  
pp. 1741-1762 ◽  
Author(s):  
L Foffano ◽  
E Prandini ◽  
A Franceschini ◽  
S Paiano
Keyword(s):  
Spectral Properties ◽  
Gamma Ray ◽  
Spectral Energy Distribution ◽  
Broad Band ◽  
High Energy ◽  
Spectral Energy ◽  
X Rays ◽  
Bl Lac Objects ◽  
X Ray ◽  
Bl Lac

ABSTRACT Extreme high-energy peaked BL Lac objects (EHBLs) are an emerging class of blazars with exceptional spectral properties. The non-thermal emission of the relativistic jet peaks in the spectral energy distribution (SED) plot with the synchrotron emission in X-rays and with the gamma-ray emission in the TeV range or above. These high photon energies may represent a challenge for the standard modelling of these sources. They are important for the implications on the indirect measurements of the extragalactic background light, the intergalactic magnetic field estimate, and the possible origin of extragalactic high-energy neutrinos. In this paper, we perform a comparative study of the multiwavelength spectra of 32 EHBL objects detected by the Swift-BAT telescope in the hard X-ray band and by the Fermi-LAT telescope in the high-energy gamma-ray band. The source sample presents uniform spectral properties in the broad-band SEDs, except for the TeV gamma-ray band where an interesting bimodality seems to emerge. This suggests that the EHBL class is not homogeneous, and a possible subclassification of the EHBLs may be unveiled. Furthermore, in order to increase the number of EHBLs and settle their statistics, we discuss the potential detectability of the 14 currently TeV gamma-ray undetected sources in our sample by the Cherenkov telescopes.

scholarly journals The hypersoft state of Cygnus X–3

2018 ◽  
Vol 612 ◽  
pp. A27 ◽  
Author(s):  
K. I. I. Koljonen ◽  
T. Maccarone ◽  
M. L. McCollough ◽  
M. Gurwell ◽  
S. A. Trushkin ◽  
...  
Keyword(s):  
Black Hole ◽  
Compact Object ◽  
Jet Quenching ◽  
Monitoring Data ◽  
X Rays ◽  
X Ray ◽  
The Galaxy ◽  
Low Mass ◽  
Unique Source ◽  
Multiwavelength Observations

Context. Cygnus X–3 is a unique microquasar in the Galaxy hosting a Wolf-Rayet companion orbiting a compact object that most likely is a low-mass black hole. The unique source properties are likely due to the interaction of the compact object with the heavy stellar wind of the companion. Aim. In this paper, we concentrate on a very specific period of time prior to the massive outbursts observed from the source. During this period, Cygnus X–3 is in a so-called hypersoft state, in which the radio and hard X-ray fluxes are found to be at their lowest values (or non-detected), the soft X-ray flux is at its highest values, and sporadic γ-ray emission is observed. We use multiwavelength observations to study the nature of the hypersoft state. Methods. We observed Cygnus X–3 during the hypersoft state with Swift and NuSTAR in X-rays and SMA, AMI-LA, and RATAN-600 in the radio. We also considered X-ray monitoring data from MAXI and γ-ray monitoring data from AGILE and Fermi. Results. We found that the spectra and timing properties of the multiwavelength observations can be explained by a scenario in which the jet production is turned off or highly diminished in the hypersoft state and the missing jet pressure allows the wind to refill the region close to the black hole. The results provide proof of actual jet quenching in soft states of X-ray binaries.

scholarly journals A black hole X-ray binary at ∼100 Hz: multiwavelength timing of MAXI J1820+070 with HiPERCAM and NICER

2019 ◽  
Vol 490 (1) ◽  
pp. L62-L66 ◽  
Author(s):  
J A Paice ◽  
P Gandhi ◽  
T Shahbaz ◽  
P Uttley ◽  
Z Arzoumanian ◽  
...  
Keyword(s):  
Black Hole ◽  
Time Scales ◽  
X Rays ◽  
X Ray ◽  
Black Hole Candidate ◽  
Optical Wavelength ◽  
The Third ◽  
Binary Black Hole ◽  
Internal Shock ◽  
Low Mass

ABSTRACT We report on simultaneous sub-second optical and X-ray timing observations of the low-mass X-ray binary black hole candidate MAXI J1820+070. The bright 2018 outburst rise allowed simultaneous photometry in five optical bands (ugrizs) with HiPERCAM/GTC (Optical) at frame rates over 100 Hz, together with NICER/ISS observations (X-rays). Intense (factor of 2) red flaring activity in the optical is seen over a broad range of time-scales down to ∼10 ms. Cross-correlating the bands reveals a prominent anticorrelation on time-scales of ∼seconds, and a narrow sub-second correlation at a lag of ≈ +165 ms (optical lagging X-rays). This lag increases with optical wavelength, and is approximately constant over Fourier frequencies of ∼0.3–10 Hz. These features are consistent with an origin in the inner accretion flow and jet base within ∼5000 Gravitational radii. An additional ∼+5 s lag feature may be ascribable to disc reprocessing. MAXI J1820+070 is the third black hole transient to display a clear ∼0.1 s optical lag, which may be common feature in such objects. The sub-second lag variation with wavelength is novel, and may allow constraints on internal shock jet stratification models.

scholarly journals Particle acceleration in low-power hotspots: modelling the broad-band spectral energy distribution

2020 ◽  
Vol 495 (2) ◽  
pp. 1593-1607 ◽  
Author(s):  
G Migliori ◽  
M Orienti ◽  
L Coccato ◽  
G Brunetti ◽  
F D’Ammando ◽  
...  
Keyword(s):  
Particle Acceleration ◽  
Energy Distribution ◽  
Low Power ◽  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Broad Band ◽  
Spectral Energy ◽  
X Rays ◽  
X Ray ◽  
Radiative Processes

ABSTRACT The acceleration and radiative processes active in low-power radio hotspots are investigated by means of new deep near-infrared (NIR) and optical Very Large Telescope (VLT) observations, complemented with archival, high-sensitivity VLT, radio Very Large Array (VLA), and X-ray Chandra data. For the three studied radio galaxies (3C 105, 3C 195, and 3C 227), we confirm the detection of NIR/optical counterparts of the observed radio hotspots. We resolve multiple components in 3C 227 West and in 3C 105 South and characterize the diffuse NIR/optical emission of the latter. We show that the linear size of this component (≳4 kpc) makes 3C 105 South a compelling case for particles’ re-acceleration in the post-shock region. Modelling of the radio-to-X-ray spectral energy distribution (SED) of 3C 195 South and 3C 227 W1 gives clues on the origin of the detected X-ray emission. In the context of inverse Compton models, the peculiarly steep synchrotron curve of 3C 195 South sets constraints on the shape of the radiating particles’ spectrum that are testable with better knowledge of the SED shape at low (≲GHz) radio frequencies and in X-rays. The X-ray emission of 3C 227 W1 can be explained with an additional synchrotron component originating in compact (<100 pc) regions, such those revealed by radio observations at 22 GHz, provided that efficient particle acceleration (γ ≳ 107) is ongoing. The emerging picture is that of systems in which different acceleration and radiative processes co-exist.

scholarly journals Estimating black hole masses in obscured AGN using X-rays

2021 ◽  
Vol 502 (3) ◽  
pp. 3329-3342
Author(s):  
Mario Gliozzi ◽  
James K Williams ◽  
Dina A Michel
Keyword(s):  
Black Hole ◽  
Broad Band ◽  
High Rate ◽  
X Rays ◽  
Host Galaxies ◽  
Scaling Method ◽  
X Ray ◽  
Band Spectra ◽  
Black Hole Masses

ABSTRACT Determining the black hole masses in active galactic nuclei (AGN) is of crucial importance to constrain the basic characteristics of their central engines and shed light on their growth and co-evolution with their host galaxies. While the black hole mass (MBH) can be robustly measured with dynamical methods in bright type 1 AGN, where the variable primary emission and the broad-line region are directly observed, a direct measurement is considerably more challenging if not impossible for the vast majority of heavily obscured type 2 AGN. In this work, we tested the validity of an X-ray-based scaling method to constrain the MBH in heavily absorbed AGN. To this end, we utilized a sample of type 2 AGN with good-quality hard X-ray data obtained by the Nuclear Spectroscopic Telescope Array satellite and with MBH dynamically constrained from megamaser measurements. Our results indicate that, when the X-ray broad-band spectra are fitted with physically motivated self-consistent models that properly account for absorption, scattering, and emission-line contributions from the putative torus and constrain the primary X-ray emission, then the X-ray scaling method yields MBH values that are consistent with those determined from megamaser measurements within their respective uncertainties. With this method, we can therefore systematically determine the MBH in any type 2 AGN, provided that they possess good-quality X-ray data and accrete at a moderate to high rate.

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