Chandra view on the active nucleus of CGCG 292–057: Jet-ISM interactions

2018 ◽  
Vol 14 (S342) ◽  
pp. 222-223
Author(s):  
K. Balasubramaniam ◽  
Ł. Stawarz ◽  
V. Marchenko ◽  
R. Thimmappa ◽  
M. Sobolewska ◽  
...  
Keyword(s):  
Power Law ◽  
Thermal Emission ◽  
Source Region ◽  
Radial Profile ◽  
Active Nucleus ◽  
Iron Line ◽  
X Ray ◽  
The Galaxy ◽  
Absorbed Power ◽  
Emission Models

AbstractWe present the analysis of the 93 ksec Chandra ACIS–S data for the galaxy CGCG 292–057 (z = 0.054), with complex radio structure indicative of the intermittent jet activity. In order to characterize precisely the spectrum of the unresolved low-luminosity active nucleus in the source, we performed detailed MARX/PSF simulations and studied the radial profile of the source region surface brightness. In this way, we have detected an additional X-ray component extending from a few up to ∼10 kpc from the unresolved core, which could be associated with the hot gaseous medium compressed and heated (up to 0.9 keV) by the expanding inner lobes of the radio galaxy. We modeled the X-ray spectrum of the unresolved nucleus assuming various emission models, including an absorbed power-law, a power-law plus thermal emission component, and a two-temperature thermal plasma. The best fit was however obtained assuming a power-law emission scattered by a hot ionized gas, giving rise to the 6.7 keV iron line.

scholarly journals An unusual transient following the short GRB 071227

2019 ◽  
Vol 489 (1) ◽  
pp. 13-27
Author(s):  
R A J Eyles ◽  
P T O’Brien ◽  
K Wiersema ◽  
R L C Starling ◽  
B P Gompertz ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Thermal Emission ◽  
Chemical Properties ◽  
Major Axis ◽  
Optical Observations ◽  
X Ray ◽  
Very Large Telescope ◽  
The Galaxy ◽  
Simple Extrapolation ◽  
Emission Models

ABSTRACT We present X-ray and optical observations of the short duration gamma-ray burst GRB 071227 and its host at z = 0.381, obtained using Swift, Gemini South, and the Very Large Telescope. We identify a short-lived and moderately bright optical transient, with flux significantly in excess of that expected from a simple extrapolation of the X-ray spectrum at 0.2–0.3 d after burst. We fit the SED with afterglow models allowing for high extinction and thermal emission models that approximate a kilonova to assess the excess’ origins. While some kilonova contribution is plausible, it is not favoured due to the low temperature and high luminosity required, implying superluminal expansion and a large ejecta mass of ∼0.1 M$\odot$. We find, instead, that the transient is broadly consistent with power-law spectra with additional dust extinction of E(B − V) ∼ 0.4 mag, although a possibly thermal excess remains in the z band. We investigate the host, a spiral galaxy with an edge-on orientation, resolving its spectrum along its major axis to construct the galaxy rotation curve and analyse the star formation and chemical properties. The integrated host emission shows evidence for high extinction, consistent with the afterglow findings. The metallicity and extinction are consistent with previous studies of this host and indicate the galaxy is a typical, but dusty, late-type SGRB host.

scholarly journals X-Ray Emission from Expanding Shells in NGC 3077

2004 ◽  
Vol 217 ◽  
pp. 310-311
Author(s):  
Jürgen Ott ◽  
Crystal L. Martin ◽  
Fabian Walter
Keyword(s):  
Thermal Emission ◽  
Dwarf Galaxy ◽  
Point Sources ◽  
Starburst Galaxy ◽  
Interstellar Gas ◽  
X Ray ◽  
Hot Gas ◽  
Hα Emission ◽  
Emission Models ◽  
Expanding Shells

Deep Chandra observations of NGC 3077, a starburst dwarf galaxy in the M81 triplet, resolve the X-ray emission from several supershells. The emission is brightest in the cavities defined by expanding shells detected previously in Hα emission. Thermal emission models fitted to the data imply temperatures ranging from 1.3 to 4.9 × 106 K. The total 0.3–6.0 keV X-ray luminosity is 2 − 5 × 1039ergs−1 (depending on the selected thermal plasma model). Most (85%) of the X-ray luminosity in NGC 3077 comes from the hot interstellar gas; the remainder comes from six X-ray point sources. The radial density profile of the hot gas is not as steep as that expected in a freely expanding wind (e.g., as seen in the neighboring starburst galaxy M 82) implying that the hot gas is still confined by the Hα shells.

scholarly journals High Resolution X-ray Observations of 3C 58

2004 ◽  
Vol 218 ◽  
pp. 185-188
Author(s):  
Patrick Slane
Keyword(s):  
High Resolution ◽  
Massive Star ◽  
Thermal Emission ◽  
Rotation Axis ◽  
Crab Nebula ◽  
X Ray ◽  
The Galaxy ◽  
Pulsar Wind ◽  
Star Surface ◽  
The Crab Nebula

As the presumed remnant of SN 1181, 3C 58 houses one of the youngest known neutron stars in the Galaxy. The properties of this young pulsar and its associated pulsar wind nebula (PWN) differ considerably from those of the Crab Nebula, and may well offer a more typical example of the endpoint of massive star collapse. High resolution X-ray studies reveal structures in the inner nebula that may be associated with the pulsar wind termination shock, a jet that may be aligned with the rotation axis, and other regions of enhanced emission. Spectral variations in the PWN are consistent with the expected evolution of the postshock flow, and complex loops of emission are seen in the nebula interior. Limits on the neutron star surface temperature fall below standard cooling models, indicating that some more rapid neutrino cooling process is required. The outer regions of 3C 58 show thermal emission with enhanced levels of neon, indicative of shocked ejecta bounding the PWN.

Three-band observations of the soft X-ray background and some implications of thermal emission models

1977 ◽  
Vol 213 ◽  
pp. 405 ◽  
Author(s):  
P. Burstein ◽  
R. J. Borken ◽  
W. L. Kraushaar ◽  
W. T. Sanders
Keyword(s):  
Thermal Emission ◽  
X Ray ◽  
Emission Models ◽  
X Ray Background

Preliminary analysis of the X-ray emission from the central regions of the Pictor A

2018 ◽  
Vol 14 (S342) ◽  
pp. 224-226
Author(s):  
R. Thimmappa ◽  
Ł. Stawarz ◽  
K. Balasubramaniam ◽  
V. Marchenko
Keyword(s):  
Surface Brightness ◽  
Radio Galaxy ◽  
Radial Profile ◽  
Host Galaxy ◽  
Active Nucleus ◽  
X Ray ◽  
Central Regions ◽  
Total Exposure Time ◽  
Radiative Output ◽  
The Individual

AbstractHere we present some preliminary results of our analysis of the combined Chandra observations of the Pictor A radio galaxy. All the available Chandra data for the target, consisting of multiple pointings spanning over 15 years and amounting to the total exposure time of 464 ks, have been included in the analysis. We studied in detail the PSFs of the core region in the individual pointings, as well as the radial profile of the X-ray surface brightness of the source in the combined dataset, in order to discriminate between the radiative output of the unresolved core and the host galaxy. Based on these, we have performed spectral modeling of the active nucleus, constraining its variability.

scholarly journals Iron Line Emission from NGC1068

1989 ◽  
Vol 134 ◽  
pp. 167-172
Author(s):  
Katsuji Koyama
Keyword(s):  
Energy Range ◽  
Power Law ◽  
Equivalent Width ◽  
Line Emission ◽  
X Rays ◽  
Iron Line ◽  
X Ray ◽  
Central Engine ◽  
Photon Index ◽  
The Continuum

X-ray emission in the 2–10 keV energy range was observed with the Ginga satellite from the Seyfert 2 galaxy NGC1068. The continuum spectrum can be described by a power-law of photon index about 1.5. An intense iron line at 6.5 keV with an equivalent width of 1.3 keV was clearly noticed. The X-ray flux was about 6 × 10 −12 erg/sec/cm2 or 3 × 1041 erg/sec, assuming a distance of 22 Mpc. The observed spectrum is consistent with the scattering and reprocessing of X-rays by the gas surrounding the central engine. With this picture we estimate that the X-ray flux of the central engine is about 1043 - 1044 erg/sec, a typical value for a Seyfert 1 galaxy.

Hybrid modelling of a high-power X-ray attenuator plasma

2018 ◽  
Vol 25 (3) ◽  
pp. 671-685
Author(s):  
Álvaro Martín Ortega ◽  
Ana Lacoste ◽  
Tiberiu Minea
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Radial Profile ◽  
Analytical Description ◽  
Gas Temperature ◽  
Beam Path ◽  
Power Absorption ◽  
X Ray ◽  
Absorbed Power ◽  
X Ray Absorption

X-ray gas attenuators act as stress-free high-pass filters for synchrotron and free-electron laser beamlines to reduce the heat load in downstream optical elements without affecting other properties of the X-ray beam. The absorption of the X-ray beam triggers a cascade of processes that ionize and heat up the gas locally, changing its density and therefore the X-ray absorption. Aiming to understand and predict the behaviour of the gas attenuator in terms of efficiencyversusgas pressure, a hybrid model has been developed, combining three approaches: an analytical description of the X-ray absorption; Monte Carlo for the electron thermalization; and a fluid treatment for the electron diffusion, recombination and excited-states relaxation. The model was applied to an argon-filled attenuator prototype built and tested at the European Synchrotron Radiation Facility, at a pressure of 200 mbar and assuming stationary conditions. The results of the model showed that the electron population thermalizes within a few nanoseconds after the X-ray pulse arrival and it occurs just around the X-ray beam path, recombining in the bulk of the gas rather than diffusing to the attenuator walls. The gas temperature along the beam path reached 850 K for 770 W of incident power and 182 W m−1of absorbed power. Around 70% of the absorbed power is released as visible and UV radiation rather than as heat to the gas. Comparison of the power absorption with the experiment showed an overall agreement both with the plasma radial profile and power absorption trend, the latter within an error smaller than 20%. This model can be used for the design and operation of synchrotron gas attenuators and as a base for a time-dependent model for free-electron laser attenuators.

scholarly journals Middle aged γ-ray pulsar J1957+5033 in X-rays: pulsations, thermal emission and nebula

2020 ◽  
Author(s):  
D A Zyuzin ◽  
A V Karpova ◽  
Y A Shibanov ◽  
A Y Potekhin ◽  
V F Suleimanov
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Power Law ◽  
Thermal Emission ◽  
Single Pulse ◽  
X Rays ◽  
Middle Aged ◽  
X Ray ◽  
Photon Index ◽  
Γ Ray

Abstract We analyze new XMM-Newton and archival Chandra observations of the middle-aged γ-ray radio-quiet pulsar J1957+5033. We detect, for the first time, X-ray pulsations with the pulsar spin period of the point-like source coinciding by position with the pulsar. This confirms the pulsar nature of the source. In the 0.15–0.5 keV band, there is a single pulse per period and the pulsed fraction is ≈18 ± 6 per cent. In this band, the pulsar spectrum is dominated by a thermal emission component that likely comes from the entire surface of the neutron star, while at higher energies (≳ 0.7 keV) it is described by a power law with the photon index Γ ≈ 1.6. We construct new hydrogen atmosphere models for neutron stars with dipole magnetic fields and non-uniform surface temperature distributions with relatively low effective temperatures. We use them in the spectral analysis and derive the pulsar average effective temperature of ≈(2 − 3) × 105 K. This makes J1957+5033 the coldest among all known thermally emitting neutron stars with ages below 1 Myr. Using the interstellar extinction–distance relation, we constrain the distance to the pulsar in the range of 0.1–1 kpc. We compare the obtained X-ray thermal luminosity with those for other neutron stars and various neutron star cooling models and set some constraints on latter. We observe a faint trail-like feature, elongated ∼8 arcmin from J1957+5033. Its spectrum can be described by a power law with a photon index Γ = 1.9 ± 0.5 suggesting that it is likely a pulsar wind nebula powered by J1957+5033.

scholarly journals Monitoring PSR B1509–58 with RXTE: Spectral analysis 1996–2010

10.14311/1474 ◽  
2011 ◽  
Vol 51 (6) ◽  
Author(s):  
E. Litzinger ◽  
K. Pottschmidt ◽  
J. Wilms ◽  
S. Suchy ◽  
R. E. Rothschild ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Power Law ◽  
Pulse Period ◽  
Spectral Parameters ◽  
High Significance ◽  
X Ray ◽  
Pulse Phase ◽  
Absorbed Power ◽  
The Stability ◽  
Over Time

We present an analysis of the X-ray spectra of the young, Crab-like pulsar PSR B1509–58 (pulse period P ~ 151ms) observed by RXTE over 14 years since the beginning of the mission in 1996. The uniform dataset is especially well suited for studying the stability of the spectral parameters over time as well as for determining pulse phase resolved spectral parameters with high significance. The phase averaged spectra as well as the resolved spectra can be well described by an absorbed power law.

scholarly journals Precise Timing and Phase-resolved Spectroscopy of the Young Pulsar J1617–5055 with NuSTAR

2021 ◽  
Vol 923 (2) ◽  
pp. 249
Author(s):  
Jeremy Hare ◽  
Igor Volkov ◽  
George G. Pavlov ◽  
Oleg Kargaltsev ◽  
Simon Johnston
Keyword(s):  
Power Law ◽  
Duty Cycle ◽  
Radio Pulse ◽  
Power Law Model ◽  
Telescope Array ◽  
X Ray ◽  
Linearly Polarized ◽  
Photon Index ◽  
Absorbed Power ◽  
Fourier Harmonics

Abstract We report on a Nuclear Spectroscopic Telescope Array (NuSTAR) observation of the young, energetic pulsar PSR J1617–5055. Parkes Observatory 3 GHz radio observations of the pulsar (taken about 7 yr before the NuSTAR observations) are also reported here. NuSTAR detected pulsations at a frequency of f ≈ 14.4 Hz (P ≈ 69.44 ms) and, in addition, the observation was long enough to measure the source’s frequency derivative, f ̇ ≈ − 2.8 × 10 − 11 Hz s−1. We find that the pulsar shows one peak per period at both hard X-ray and radio wavelengths, but that the hard X-ray pulse is broader (having a duty cycle of ∼0.7), than the radio pulse (having a duty cycle of ∼0.08). Additionally, the radio pulse is strongly linearly polarized. J1617's phase-integrated hard X-ray spectrum is well fit by an absorbed power-law model, with a photon index Γ = 1.59 ± 0.02. The hard X-ray pulsations are well described by three Fourier harmonics, and have a pulsed fraction that increases with energy. We also fit the phase-resolved NuSTAR spectra with an absorbed power-law model in five phase bins and find that the photon index varies with phase from Γ = 1.52 ± 0.03 at phases around the flux maximum to Γ = 1.79 ± 0.06 around the flux minimum. Last, we compare our results with other pulsars whose magnetospheric emission is detected at hard X-ray energies and find that, similar to previous studies, J1617's hard X-ray properties are more similar to the MeV pulsars than the GeV pulsars.

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