scholarly journals A two-sided but significantly beamed jet in the supercritical accretion quasar IRAS F11119+3257

2020 ◽  
Vol 494 (2) ◽  
pp. 1744-1750 ◽  
Author(s):  
Jun Yang ◽  
Zsolt Paragi ◽  
Tao An ◽  
Willem A Baan ◽  
Prashanth Mohan ◽  
...  
Keyword(s):  
Density Ratio ◽  
Radio Spectrum ◽  
Radio Structure ◽  
X Ray ◽  
Bolometric Luminosity ◽  
Long Baseline ◽  
Supercritical Accretion ◽  
Thin Part ◽  
Best Fitting ◽  
Eddington Limit

ABSTRACT Highly accreting quasars are quite luminous in the X-ray and optical regimes; while, they tend to become radio quiet and have optically thin radio spectra. Among the known quasars, IRAS F11119+3257 is a supercritical accretion source because it has a bolometric luminosity slightly above the Eddington limit and extremely powerful X-ray outflows. To probe its radio structure, we investigated its radio spectrum between 0.15 and 96.15 GHz and performed very-long-baseline interferometric (VLBI) observations with the European VLBI Network (EVN) at 1.66 and 4.93 GHz. The deep EVN image at 1.66 GHz shows a two-sided jet with a projected separation about 200 pc and a very high flux density ratio of about 290. Together with the best-fitting value of the integrated spectral index of −1.31 ± 0.02 in the optically thin part, we infer that the approaching jet has an intrinsic speed at least 0.57 times of the light speed. This is a new record among the known all kinds of super-Eddington accreting sources and unlikely accelerated by the radiation pressure in a certain models. We propose a scenario in which IRAS F11119+3257 is an unusual compact symmetric object with a small jet viewing angle and a radio spectrum peaking at 0.53 ± 0.06 GHz mainly due to the synchrotron self-absorption.

scholarly journals Measurements of Outburst Characteristics, Temperatures, Densities and Abundances in the Ejecta of Nova Muscae 1983

1990 ◽  
Vol 122 ◽  
pp. 202-203
Author(s):  
B.J.M. Hassall ◽  
M.A.J. Snijders ◽  
A. W. Harris ◽  
A. Cassatella ◽  
M. Dennefeld ◽  
...  
Keyword(s):  
Interstellar Extinction ◽  
Radiative Energy ◽  
Gravitational Potential Energy ◽  
X Ray ◽  
Bolometric Luminosity ◽  
Fast Speed ◽  
Total Luminosity ◽  
Thermonuclear Runaway ◽  
Outburst Energy ◽  
Eddington Limit

We present results for IUE, optical and IR observations of Nova Muscae 1983, from early outburst to January 1986 obtained by the European IUE Target of Opportunity Team. A detailed description of the data will appear elsewhere (Hassall et al., 1989), but here we summarise the most important results.The outburst lightcurve initially indicated a fast speed class for this nova, but was later characterised by a rather slow optical decline with two or more secondary outbursts with sudden doubling of the bolometric flux. In Figure 1, we show the contributions of X-ray, UV, optical and IR to the total luminosity for 1200 days following outburst, assuming a distance of 4.3kpc and an interstellar extinction E(B-V)=0.5. In the absence of dust formation, first the UV and later the X-ray flux (Ögelman et al, 1984) dominate the radiative energy late into the nebular phase. There was a plateau stage lasting about 500 days, with a bolometric luminosity of ~ 1038ergs s−1 near the Eddington limit. The secondary outbursts were thus super-Eddington. We estimate a total outburst energy (including kinetic and gravitational potential energy of the ejecta) of ~ 5·l046 ergs, corresponding to a mass of ~ 4·10−6Mº of hydrogen burnt in the thermonuclear runaway.

scholarly journals Variability and parsec-scale radio structure of candidate compact symmetric objects

2020 ◽  
Vol 499 (1) ◽  
pp. 1340-1355 ◽  
Author(s):  
M Orienti ◽  
D Dallacasa
Keyword(s):  
Flux Density ◽  
Expansion Velocity ◽  
Radio Structure ◽  
Very Large Array ◽  
Long Baseline ◽  
Thick Part ◽  
Thin Part ◽  
Almost All ◽  
Very Long Baseline Array ◽  
Fast Evolution

ABSTRACT We report results on multiepoch Very Large Array (VLA) and pc-scale Very Long Baseline Array (VLBA) observations of candidate compact symmetric objects (CSOs) from the faint sample of high-frequency peakers. New VLBA observations could resolve the radio structure in about 42 per cent of the observed sources, showing double components that may be either mini-lobes or core-jet structures. Almost all the sources monitored by the VLA show some variability on time-scale of a decade, and only one source does not show any significant variation. In 17 sources, the flux density changes randomly as it is expected in blazars, and in four sources the spectrum becomes flat in the last observing epoch, confirming that samples selected in the GHz regime are highly contaminated by beamed objects. In 16 objects, the pc-scale and variability properties are consistent with a young radio source in adiabatic expansion, with a steady decrease of the flux density in the optically thin part of the spectrum, and a flux density increase in the optically thick part. For these sources, we estimate dynamical ages between a few tens to a few hundred years. The corresponding expansion velocity is generally between 0.1c and 0.7c, similar to values found in CSOs with different approaches. The fast evolution that we observe in some CSO candidates suggests that not all the objects would become classical Fanaroff–Riley radio sources.

scholarly journals On the Progenitors of Type Ia Supernovae

2002 ◽  
Vol 187 ◽  
pp. 103-108
Author(s):  
X.-D. Li ◽  
E. P. J. van den Heuvel
Keyword(s):  
Nuclear Fuel ◽  
White Dwarfs ◽  
Radiation Temperature ◽  
Type Ia Supernovae ◽  
Characteristic Radiation ◽  
X Ray ◽  
Bolometric Luminosity ◽  
Type Ia ◽  
Ia Supernovae ◽  
Eddington Limit

Supersoft X-ray sources (hereafter SSS) are a class of luminous (bolometric luminosity ~ 1037 − 1038 erg s−1) objects with a characteristic radiation temperature of 30 to 60 eV (Hasinger 1994; Kahabka & Trümper 1996). The most popular model for SSS is that they are massive white dwarfs steadily burning nuclear fuel accreted from a more massive binary companion at a rate near or above the Eddington limit (van den Heuvel et al. 1992).

scholarly journals Extended X-ray emission in PKS 1718−649

2018 ◽  
Vol 612 ◽  
pp. L4 ◽  
Author(s):  
T. Beuchert ◽  
A. Rodríguez-Ardila ◽  
V. A. Moss ◽  
R. Schulz ◽  
M. Kadler ◽  
...  
Keyword(s):  
Large Scale ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Effective Area ◽  
Radio Spectrum ◽  
Host Galaxy ◽  
X Rays ◽  
Radio Structure ◽  
X Ray ◽  
Close Proximity

PKS 1718−649 is one of the closest and most comprehensively studied candidates of a young active galactic nucleus (AGN) that is still embedded in its optical host galaxy. The compact radio structure, with a maximal extent of a few parsecs, makes it a member of the group of compact symmetric objects (CSO). Its environment imposes a turnover of the radio synchrotron spectrum towards lower frequencies, also classifying PKS 1718−649 as gigahertz-peaked radio spectrum (GPS) source. Its close proximity has allowed the first detection of extended X-ray emission in a GPS/CSO source with Chandra that is for the most part unrelated to nuclear feedback. However, not much is known about the nature of this emission. By co-adding all archival Chandra data and complementing these datasets with the large effective area of XMM-Newton, we are able to study the detailed physics of the environment of PKS 1718−649. Not only can we confirm that the bulk of the ≲kiloparsec-scale environment emits in the soft X-rays, but we also identify the emitting gas to form a hot, collisionally ionized medium. While the feedback of the central AGN still seems to be constrained to the inner few parsecs, we argue that supernovae are capable of producing the observed large-scale X-ray emission at a rate inferred from its estimated star formation rate.

scholarly journals X-ray radiation of the jets and the supercritical accretion disk in SS 433

2010 ◽  
Vol 6 (S275) ◽  
pp. 280-284 ◽  
Author(s):  
Sergei Fabrika ◽  
Alexei Medvedev
Keyword(s):  
Accretion Disk ◽  
Spectral Component ◽  
Emission Lines ◽  
X Rays ◽  
X Ray ◽  
Ss 433 ◽  
Disk Wind ◽  
Bolometric Luminosity ◽  
Supercritical Accretion ◽  
The Continuum

AbstractThe observed X-ray luminosity of SS 433 is ~1036 erg/s, it is known that all the radiation is formed in the famous SS 433 jets. The bolometric luminosity of SS 433 is ~1040 erg/s, and originally the luminosity must be realized in X-rays. The original radiation is probably thermalized in the supercritical accretion disk wind, however the missing more than four orders of magnitude is surprising. We have analysed the XMM-Newton spectra of SS 433 using a model of adiabatically and radiatively cooling X-ray jets. The multi-temperature thermal jet model reproduces very well the strongest observed emission lines, but it can not reproduce the continuum radiation and some spectral features. We have found a notable contribution of ionized reflection to the spectrum in the energy range from ~3 to 12 keV. The reflected spectrum is an evidence of the supercritical disk funnel, where the illuminating radiation comes from deeper funnel regions, to be further reflected in the outer visible funnel walls (r ≥ 2 ⋅ 1011 cm). The illuminating spectrum is similar to that observed in ULXs, its luminosity has to be no less than ~1039 erg/s. A soft excess has been detected, that does not depend on the thermal jet model details. It may be represented as a BB with a temperature of Tbb ≈ 0.1 keV and luminosity of Lbb~3 ⋅ 1037 erg/s. The soft spectral component has about the same parameters as those found in ULXs.

scholarly journals The 2019 super-Eddington outburst of RX J0209.6−7427: detection of pulsations and constraints on the magnetic field strength

2020 ◽  
Vol 494 (4) ◽  
pp. 5350-5359 ◽  
Author(s):  
G Vasilopoulos ◽  
P S Ray ◽  
K C Gendreau ◽  
P A Jenke ◽  
G K Jaisawal ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Broad Band ◽  
Accurate Estimate ◽  
X Ray ◽  
Bolometric Luminosity ◽  
Order Of Magnitude ◽  
Moderate Magnetic Field ◽  
Eddington Limit

ABSTRACT In 2019 November, MAXI detected an X-ray outburst from the known Be X-ray binary system RX J0209.6−7427 located in the outer wing of the Small Magellanic Cloud. We followed the outburst of the system with NICER, which led to the discovery of X-ray pulsations with a period of 9.3 s. We analysed simultaneous X-ray data obtained with NuSTAR and NICER, allowing us to characterize the spectrum and provide an accurate estimate of its bolometric luminosity. During the outburst, the maximum broad-band X-ray luminosity of the system reached (1–2) × 1039 erg s−1, thus exceeding by about one order of magnitude the Eddington limit for a typical 1.4 M⊙ mass neutron star (NS). Monitoring observations with Fermi/GBM and NICER allowed us to study the spin evolution of the NS and compare it with standard accretion torque models. We found that the NS magnetic field should be of the order of 3 × 1012 G. We conclude that RX J0209.6−7427 exhibited one of the brightest outbursts observed from a Be X-ray binary pulsar in the Magellanic Clouds, reaching similar luminosity level to the 2016 outburst of SMC X-3. Despite the super-Eddington luminosity of RX J0209.6−7427, the NS appears to have only a moderate magnetic field strength.

scholarly journals A statistical study of the relationship between X-ray, optical and radio luminosity for a sample of QSOs

1986 ◽  
Vol 119 ◽  
pp. 263-264
Author(s):  
D.M. Worrall ◽  
P. Giommi ◽  
H. Tananbaum ◽  
G. Zamorani
Keyword(s):  
Statistical Study ◽  
Radio Spectrum ◽  
Separate Component ◽  
Radio Luminosity ◽  
Radio Structure ◽  
X Ray ◽  
The Core ◽  
Extended Radio ◽  
The Relationship ◽  
Increasing Function

Our statistical study finds that the X-ray luminosity, lx for an average QSO of given optical luminosity, lo is an increasing function of radio luminosity, lr. An average QSO of given lo and lr has higher lx if the radio spectrum is flat than if it is steep. The correlation between lx, lo and lr appears to be improved if lr refers only to core emission, lrcore. Assuming an average radio-loud QSO is a radio-quiet QSO with a separate component which produces lrcore and Ixcore, lxcore/lrcore is larger if the core is that of a QSO with extended radio structure than if that of a compact flat-spectrum QSO.

scholarly journals IUE Studies of Luminous X-Ray Binaries

1983 ◽  
Vol 6 ◽  
pp. 648-648
Author(s):  
J.B. Hutchings
Keyword(s):  
Magellanic Clouds ◽  
Thick Shell ◽  
High Luminosity ◽  
Uv Spectrum ◽  
X Ray ◽  
Unique Object ◽  
The Future ◽  
Orbit Inclination ◽  
Supercritical Accretion ◽  
X Ray Binaries

IUE has been used to study 11 high luminosity X-ray binaries, of which 3 are in the Magellanic Clouds. In the supergiant systems, X-ray ionisation bubbles have been found in most cases, leading to a greater understanding of the winds and accretion processes. Further studies of precessing objects such as LMC X-4 with IUE and ST are clearly of considerable interest, relating to X-ray heating and blanketing. Detailed studies of the Cyg X-l ionisation bubble may resolve the long standing puzzle of its orbit inclination and masses. UV continua have furnished valuable information on extinction, temperatures and luminosities, and the presence of non-stellar (i.e. disk) luminosity. Here too, more detailed studies are clearly indicated for the future. A unique object of interest is the LMC transient 0538-66 whose UV spectrum has quasarlike lines and luminosity which varies oppositely to the visible. This may be a case of supercritical accretion generating an optically thick shell (“disk”) about the pulsar.

scholarly journals A Comparison of the X-ray Spectra of Quasars and BL Lac Objects

1989 ◽  
Vol 134 ◽  
pp. 197-198
Author(s):  
D. M. Worrall ◽  
B. J. Wilkes
Keyword(s):  
Power Law ◽  
Radio Spectrum ◽  
Spectral Indices ◽  
Mean Power ◽  
Bl Lac Objects ◽  
X Ray ◽  
Bl Lac ◽  
Infrared Frequencies

Quasars with similar core-compact radio properties can be classified by their differences at optical and infrared frequencies. Their X-ray properties might be expected to be similar if the synchrotron self-Compton mechanism relates their radio and X-ray emission. We have compared the 0.2–3.5 keV mean power-law energy spectral indices, , for 4 quasar classes: 12 Highly Polarized QSOs (HPQs), 19 Flat Radio Spectrum, core-compact, low-polarization, QSOs (FRS QSOs), 24 radio-selected BL Lac objects, and 7 X-ray-selected BL Lac objects.

AGN1 vs AGN2 dichotomy as seen from the point of view of ionized outflows

2019 ◽  
Vol 15 (S356) ◽  
pp. 96-96
Author(s):  
Eleonora Sani
Keyword(s):  
Accretion Rate ◽  
Point Of View ◽  
Emission Lines ◽  
Black Hole Mass ◽  
X Ray ◽  
Bolometric Luminosity ◽  
Wide Range ◽  
Strong Contrast

AbstractI present a detailed study of ionized outflows in a large sample of 650 hard X-ray detected AGN. Taking advantage of the legacy value of the BAT AGN Spectroscopic Survey (BASS, DR1), we are able to reveal the faintest wings of the [OIII] emission lines associated with outflows. The sample allows us to derive the incidence of outflows covering a wide range of AGN bolometric luminosity and test how the outflow parameters are related with various AGN power tracers, such as black hole mass, Eddington ratio, luminosity. I’ll show how ionized outflows are more frequently found in type 1.9 and type 1 AGN (50% and 40%) with respect to the low fraction in type 2 AGN (20%). Within such a framework, I’ll demonstrate how type 2 AGN outflows are almost evenly balanced between blue- and red-shifted winds. This, in strong contrast with type 1 and type 1.9 AGN outflows which are almost exclusively blue-shifted. Finally, I’ll prove how the outflow occurrence is driven by the accretion rate, whereas the dependence of outflow properties with respect to the other AGN power tracers happens to be quite mild.

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