2. Bright AGN phase
... radiation of AGNs expels gases to quench both accretion and star formation. 4. Faint AGN phases accreting at very low rates 0.01M / M Edd . ...
... radiation of AGNs expels gases to quench both accretion and star formation. 4. Faint AGN phases accreting at very low rates 0.01M / M Edd . ...
Wolfgang Voges
... Cumulative X-ray cluster number counts of the RASS/SDSSclusters (histograms) for a log-likelihood minimum of 15 applied to SDSS data (continuous line), for 25 (lower dashed line), and for 5 (upper dashed line). The RASS/SDSS cluster counts are compared with results obtained with other surveys (squar ...
... Cumulative X-ray cluster number counts of the RASS/SDSSclusters (histograms) for a log-likelihood minimum of 15 applied to SDSS data (continuous line), for 25 (lower dashed line), and for 5 (upper dashed line). The RASS/SDSS cluster counts are compared with results obtained with other surveys (squar ...
Sardinia_SA - Mullard Space Science Laboratory
... • Typical amplitudes of Nova outbursts are larger, perhaps 10– 15 magnitudes (factor 104–106) and recur on at least very long timescales different mechanism is operating • This is now known to be thermonuclear burning of the accreted material on the white dwarf Hellier (2001) from AAVSO data ...
... • Typical amplitudes of Nova outbursts are larger, perhaps 10– 15 magnitudes (factor 104–106) and recur on at least very long timescales different mechanism is operating • This is now known to be thermonuclear burning of the accreted material on the white dwarf Hellier (2001) from AAVSO data ...
Document
... thin if emitting material has Lorentz factor > 100 -> Ultrarelativistic outflow (fastest bulk flow in the universe) ...
... thin if emitting material has Lorentz factor > 100 -> Ultrarelativistic outflow (fastest bulk flow in the universe) ...
The Milky Way-Pulsars and Isolated Neutron Stars
... on old V-2 (captured in Germany after the World War II) and Aerobee rockets, they were the first who detected X-rays from the very hot gas in the solar corona. However, the intensity of this radiation was found to be a factor 106 lower than that measured at optical wavelengths. In the late 1 X-rays ...
... on old V-2 (captured in Germany after the World War II) and Aerobee rockets, they were the first who detected X-rays from the very hot gas in the solar corona. However, the intensity of this radiation was found to be a factor 106 lower than that measured at optical wavelengths. In the late 1 X-rays ...
Matter under extreme conditions experiments at the Linac
... electrons that propagate along filaments and lead to energetic particle beams [9]. Extremely high magnetic fields surround the filaments and affect energy transport and ionization. The target interior is also an intense source of positrons and high-energy photons, x- and γ-rays. LCLS will allow us t ...
... electrons that propagate along filaments and lead to energetic particle beams [9]. Extremely high magnetic fields surround the filaments and affect energy transport and ionization. The target interior is also an intense source of positrons and high-energy photons, x- and γ-rays. LCLS will allow us t ...
Low frequency radio observations of gamma-ray binaries
... new ideas and new theoretical perspectives are taken into account in order to maintain a consistent model which explains the observations of high energy sources. High-Energy Astrophysics is the study of those astrophysical systems displaying X-ray or gamma-ray emission, but also those which emits ne ...
... new ideas and new theoretical perspectives are taken into account in order to maintain a consistent model which explains the observations of high energy sources. High-Energy Astrophysics is the study of those astrophysical systems displaying X-ray or gamma-ray emission, but also those which emits ne ...
PDF only - at www.arxiv.org.
... velocity dispersion in the potential (about 700 km s-1 at that radius as inferred from the X-ray measured temperature of the intracluster medium8) at radius R ~ 25 kpc; tidal acceleration is smaller by 2l/R. The most likely force to balance a filament against gravity is that due to the tangential c ...
... velocity dispersion in the potential (about 700 km s-1 at that radius as inferred from the X-ray measured temperature of the intracluster medium8) at radius R ~ 25 kpc; tidal acceleration is smaller by 2l/R. The most likely force to balance a filament against gravity is that due to the tangential c ...
The low-spin black hole in LMC X-3 Please share
... elements), we repeat our spectral fits to the pre-selection of 1454 spectra. Mass is sampled from M: 5–11 M , inclination i: 60◦ –75◦ , and D : 41–56 kpc. The values of L/LEdd depend upon M, i, and D, but typically ∼400 thermal spectra fulfill the luminosity criterion. At each gridpoint, the distri ...
... elements), we repeat our spectral fits to the pre-selection of 1454 spectra. Mass is sampled from M: 5–11 M , inclination i: 60◦ –75◦ , and D : 41–56 kpc. The values of L/LEdd depend upon M, i, and D, but typically ∼400 thermal spectra fulfill the luminosity criterion. At each gridpoint, the distri ...
SPECTRAL STATE DEPENDENCE OF THE 0.4–2 MEV
... the launch of the satellite; preliminary results of the very first observations are described by Pottschmidt et al. (2003a). In LRW11, we first considered all uninterrupted INTEGRAL pointings, also called “science windows” (ScWs), where Cyg X-1 had an offset angle of less than 10° from the center of t ...
... the launch of the satellite; preliminary results of the very first observations are described by Pottschmidt et al. (2003a). In LRW11, we first considered all uninterrupted INTEGRAL pointings, also called “science windows” (ScWs), where Cyg X-1 had an offset angle of less than 10° from the center of t ...
L. Zampieri - Astrophysics Group of the University of Crete
... Try to explan it within the framework of BH formation from the direct collapse of massive stars in low-metallicity environments: If a massive star retains an envelope more massive than ~30-40 Msun at the time of explosion, it may collapse directly to form a BH (Zampieri 02; Heger et al. 03) The BH m ...
... Try to explan it within the framework of BH formation from the direct collapse of massive stars in low-metallicity environments: If a massive star retains an envelope more massive than ~30-40 Msun at the time of explosion, it may collapse directly to form a BH (Zampieri 02; Heger et al. 03) The BH m ...
Y.Ueda_Future_HE_Mission2006 - X
... The XRB below ~ 6 keV has been almost completely resolved and identified and hence is well understood. Howerver, even with the deepest Chandra/XMM surveys a significant fraction of the XRB remains unresolved above 6 keV (Worsley et al. 2004). Above 10 keV only 1 percent of the XRB is resolved at pre ...
... The XRB below ~ 6 keV has been almost completely resolved and identified and hence is well understood. Howerver, even with the deepest Chandra/XMM surveys a significant fraction of the XRB remains unresolved above 6 keV (Worsley et al. 2004). Above 10 keV only 1 percent of the XRB is resolved at pre ...
Cosmological dynamics with non-minimally coupled scalar field and
... Keywords: Cosmic acceleration, Parametrization, Deceleration parameter, Data analysis ...
... Keywords: Cosmic acceleration, Parametrization, Deceleration parameter, Data analysis ...
SOLAR HARD X-RAY AND GAMMA-RAY OBSERVATIONS FROM
... accelerated during solar flares. Since the beginning of 1990 the PHEBUS instrument and the SIGMA anticoincidence shield aboard GRANAT have provided hard X-ray and gamma-ray observations of solar bursts in the energy range 0.075-124 and 0.200-15 MeV, respectively. After a brief description of the exp ...
... accelerated during solar flares. Since the beginning of 1990 the PHEBUS instrument and the SIGMA anticoincidence shield aboard GRANAT have provided hard X-ray and gamma-ray observations of solar bursts in the energy range 0.075-124 and 0.200-15 MeV, respectively. After a brief description of the exp ...
The keV–TeV connection in gamma-ray binaries
... The gamma-ray emission from astrophysical sources is arguably different from the emission in the rest of the electromagnetic spectrum because it cannot be generated by hot matter. High energy gamma radiation is therefore an indication that non-thermal processes, which are able to concentrate a large ...
... The gamma-ray emission from astrophysical sources is arguably different from the emission in the rest of the electromagnetic spectrum because it cannot be generated by hot matter. High energy gamma radiation is therefore an indication that non-thermal processes, which are able to concentrate a large ...
The XXL Survey - I. Scientific motivations − XMM
... toward science driven by extensive surveys (e.g. the Sloan Digitized Sky Suvey, SDSS) that are augmented by supplemental observations. Recent years have seen a dramatic growth in the scope of multiwavelength programmes, from ultra-deep areas of the order of 1 deg2 to wide-area surveys covering hundr ...
... toward science driven by extensive surveys (e.g. the Sloan Digitized Sky Suvey, SDSS) that are augmented by supplemental observations. Recent years have seen a dramatic growth in the scope of multiwavelength programmes, from ultra-deep areas of the order of 1 deg2 to wide-area surveys covering hundr ...
L31 ON THE DISAPPEARANCE OF KILOHERTZ QUASI
... disk. Moreover, it is now well established that the frequency of kHz QPOs is not well correlated with X-ray flux over a long period of time, although short-term linear correlations seem to be present (Zhang et al. 1998a; Méndez 2000 and references therein). Therefore, for 4U 1820230, the observed e ...
... disk. Moreover, it is now well established that the frequency of kHz QPOs is not well correlated with X-ray flux over a long period of time, although short-term linear correlations seem to be present (Zhang et al. 1998a; Méndez 2000 and references therein). Therefore, for 4U 1820230, the observed e ...
The Sun as an X-Ray Star. III. Flares
... really observed and spatially resolved by the Y ohkoh/SXT as templates : we will apply here the method illustrated in Papers I and II to obtain the evolving EM(T ) and stellarlike Ñare spectra as observed by nonsolar instruments, in particular the Solid-state Imaging Spectrometer (SIS) on board the ...
... really observed and spatially resolved by the Y ohkoh/SXT as templates : we will apply here the method illustrated in Papers I and II to obtain the evolving EM(T ) and stellarlike Ñare spectra as observed by nonsolar instruments, in particular the Solid-state Imaging Spectrometer (SIS) on board the ...
Richard Congdon. pdf
... (Mahoney et al, 1980). Table 2 shows a time line (continued from Table 1) adapted from material produced by (NASA, 2007) and (Prantzos & Diehl, 1996). Year ...
... (Mahoney et al, 1980). Table 2 shows a time line (continued from Table 1) adapted from material produced by (NASA, 2007) and (Prantzos & Diehl, 1996). Year ...
The star-forming environment of an ultraluminous X-ray
... 4 Laboratory for High Energy Astrophysics, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA 2 Harvard-Smithsonian ...
... 4 Laboratory for High Energy Astrophysics, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA 2 Harvard-Smithsonian ...
The Be/X-ray transient 4U 0115+ 63/V635 Cassiopeiae
... stars ranges from 3 to 12 stellar radii. The separation of the two peaks of Hα, ∆vpeak , is significantly wider than 2v sin i (RHα /R∗ )−1 expected in an angular-momentum conserving disc, but is consistent with a disc structure in which the rotation velocity is near Keplerian. Although there is no w ...
... stars ranges from 3 to 12 stellar radii. The separation of the two peaks of Hα, ∆vpeak , is significantly wider than 2v sin i (RHα /R∗ )−1 expected in an angular-momentum conserving disc, but is consistent with a disc structure in which the rotation velocity is near Keplerian. Although there is no w ...
Title The Correlation between Dispersion Measure and X
... including the atmosphere composition, surface magnetic field, and gravity. 4. For pulsars associated with bright PWNe, the nebular NH values are adopted if they are better constrained than those of the pulsars, because the simple PL spectra of PWNe can reduce systematic uncertainties in spectral mod ...
... including the atmosphere composition, surface magnetic field, and gravity. 4. For pulsars associated with bright PWNe, the nebular NH values are adopted if they are better constrained than those of the pulsars, because the simple PL spectra of PWNe can reduce systematic uncertainties in spectral mod ...
1e 1048.1−5937, xte j1810−197 and 4u 0142+61
... detected emission feature is at an energy of ≈13 keV. In the magnetar model the common interpretation is that these lines are proton-cyclotron in origin, implying a magnetic field of ≈2 × 1015 G. The major challenge with this view is that since all three sources show the line at the same energy, the ...
... detected emission feature is at an energy of ≈13 keV. In the magnetar model the common interpretation is that these lines are proton-cyclotron in origin, implying a magnetic field of ≈2 × 1015 G. The major challenge with this view is that since all three sources show the line at the same energy, the ...
Magnetars: properties, origin and evolution
... same class of astrophysical objects. Bursts from magnetars had been observed since the end of the 1970s (Mazets et al. 1979a,b). They were initially classified as a sub-class of γ-ray bursts, with the peculiarity of a softer spectrum and of coming repeatedly from the same sky directions (Norris et a ...
... same class of astrophysical objects. Bursts from magnetars had been observed since the end of the 1970s (Mazets et al. 1979a,b). They were initially classified as a sub-class of γ-ray bursts, with the peculiarity of a softer spectrum and of coming repeatedly from the same sky directions (Norris et a ...
FERMI GBM detections of four AXPs at soft gamma-rays
... A breakthrough in SGR and magnetar physics was reached when Kouveliotou et al. (1998) measured the period and period derivative of SGR 1806-20. From these measurements, they found that the observed persistent X-ray flux of this SGR is two orders of magnitude higher than what can be explained from ro ...
... A breakthrough in SGR and magnetar physics was reached when Kouveliotou et al. (1998) measured the period and period derivative of SGR 1806-20. From these measurements, they found that the observed persistent X-ray flux of this SGR is two orders of magnitude higher than what can be explained from ro ...
History of X-ray astronomy
The history of X-ray astronomy begins in the 1920s, with interest in short wave communications for the U.S. Navy. This was soon followed by extensive study of the earth's ionosphere. By 1927, interest in the detection of X-ray and ultraviolet (UV) radiation at high altitudes inspired researchers to launch Goddard's rockets into the upper atmosphere to support theoretical studies and data gathering. The first successful rocket flight equipped with instrumentation able to detect solar ultraviolet radiation occurred in 1946. X-ray solar studies began in 1949. By 1973 a solar instrument package orbited on Skylab providing significant solar data.In 1965 the Goddard Space Flight Center program in X-ray astronomy was initiated with a series of balloon-borne experiments. In the 1970s this was followed by high altitude sounding rocket experiments, and that was followed by orbiting (satellite) observatories.The first rocket flight to successfully detect a cosmic source of X-ray emission was launched in 1962 by a group at American Science and Engineering (AS&E).X-ray wavelengths reveal information about the bodies (sources) that emit them.