Gamma - Ray Observations of Olaf Reimer
... • Crux region AGILE observes variability and detects new transients on time scales of 1 day at flux levels of 106 cm-2s-1 , even in crowded, high diffuse emission Galactic plane regions. NO detectable simultaneous hard X-ray emission (F < 20-30 mCrab, 18-60 keV, 1-day integration) GLAST: Expectation ...
... • Crux region AGILE observes variability and detects new transients on time scales of 1 day at flux levels of 106 cm-2s-1 , even in crowded, high diffuse emission Galactic plane regions. NO detectable simultaneous hard X-ray emission (F < 20-30 mCrab, 18-60 keV, 1-day integration) GLAST: Expectation ...
Dynamics of nuclear burning during type-I X-ray bursts 1. 2. 3.
... accretion through Roche lobe overflow •Accretion of H and He, ...
... accretion through Roche lobe overflow •Accretion of H and He, ...
Rogava_Course_-_First_lecture
... • Detached binaries are a kind of binary stars where each component is within its Roche lobe. No major impact on each other, stars essentially evolve separately. • Semidetached binary stars: one of the components fills its Roche lobe and the other does not. Gas from the surface of the Roche lobe fil ...
... • Detached binaries are a kind of binary stars where each component is within its Roche lobe. No major impact on each other, stars essentially evolve separately. • Semidetached binary stars: one of the components fills its Roche lobe and the other does not. Gas from the surface of the Roche lobe fil ...
Circumstellar interaction of supernovae and gamma-ray bursts
... Blast wave shock : Ejecta expansion speed is much higher than sound speed. Shocked CSM: Interaction of blast wave with CSM . CSM is accelerated, compressed, heated and shocked. ...
... Blast wave shock : Ejecta expansion speed is much higher than sound speed. Shocked CSM: Interaction of blast wave with CSM . CSM is accelerated, compressed, heated and shocked. ...
the effect of an soft X-ray source near the compact object in LS 5039
... Target photons are changed to 100eV photons, so photon density increases → IC cooling time becomes short → the number of e± decreases U100eV U Ostar ~ L100eV LOstar ( ROstar R100eV ) 2 ~ 103 No variation in GeV & X-ray band In Y&T 2010, e± scattered off stellar photons → each flux modulates by t ...
... Target photons are changed to 100eV photons, so photon density increases → IC cooling time becomes short → the number of e± decreases U100eV U Ostar ~ L100eV LOstar ( ROstar R100eV ) 2 ~ 103 No variation in GeV & X-ray band In Y&T 2010, e± scattered off stellar photons → each flux modulates by t ...
Document
... Bazars are powerful gamma-ray sources. The most powerful of them have equivalent isotropic luminosity 1049 erg/s. Collimation θ2/2 ~ 10-2 – 10-3. θ – jet opening angle. EGRET detected 66 (+27) sources of this type. New breakthrough is expected after the launch of GLAST. Several sources have been det ...
... Bazars are powerful gamma-ray sources. The most powerful of them have equivalent isotropic luminosity 1049 erg/s. Collimation θ2/2 ~ 10-2 – 10-3. θ – jet opening angle. EGRET detected 66 (+27) sources of this type. New breakthrough is expected after the launch of GLAST. Several sources have been det ...
Black holes in binary systems and galatic nuclei
... Search for binary supermassive BHs in galactic nuclei (e.g. Sanders and Mirabel, 1996; Komossa et al., 2003). Observations of X-ray and ultraviolet-optical flares from the tidal disruption of stars near supermassive BHs in galactic nuclei (Komossa et al., 1997, 2002; Gezari et al., 2012). Investigat ...
... Search for binary supermassive BHs in galactic nuclei (e.g. Sanders and Mirabel, 1996; Komossa et al., 2003). Observations of X-ray and ultraviolet-optical flares from the tidal disruption of stars near supermassive BHs in galactic nuclei (Komossa et al., 1997, 2002; Gezari et al., 2012). Investigat ...
Identification of the optical counterparts of high-mass X
... In HMXBs, X/γ-rays are produced as the result of accretion of matter onto the neutron star. The way how matter is transferred from the massive star differs in each case. Among HMXBs with evolved companions there are disk-fed and windfed systems depending upon whether accreted matter is transferred t ...
... In HMXBs, X/γ-rays are produced as the result of accretion of matter onto the neutron star. The way how matter is transferred from the massive star differs in each case. Among HMXBs with evolved companions there are disk-fed and windfed systems depending upon whether accreted matter is transferred t ...
Chandra Characterization of X-ray Emission in the Young F
... sweet spot of the S3 chip. We re-processed the Chandra data with CIAO version 4.8 (Fruscione et al. 2006), which applied the energy dependent sub-pixel event repositioning. The total program observing time was 39 ksec, and the total on-target observing time was 37.3 ksec, in which 1509 total raw pho ...
... sweet spot of the S3 chip. We re-processed the Chandra data with CIAO version 4.8 (Fruscione et al. 2006), which applied the energy dependent sub-pixel event repositioning. The total program observing time was 39 ksec, and the total on-target observing time was 37.3 ksec, in which 1509 total raw pho ...
A propelling neutron star in the enigmatic Be-star γ Cassiopeia
... We suggest that the low-mass companion of γ Cas can be an NS in the propeller stage. The NS orbits the Be-star in almost circular orbit coplanar with the Be-disc. The Be-disc is contained within the Roche lobe of the Be-star (∼310 R ),1 and the NS gravitationally captures matter from the slow Be-di ...
... We suggest that the low-mass companion of γ Cas can be an NS in the propeller stage. The NS orbits the Be-star in almost circular orbit coplanar with the Be-disc. The Be-disc is contained within the Roche lobe of the Be-star (∼310 R ),1 and the NS gravitationally captures matter from the slow Be-di ...
cohen_paris_v2_may2009 - Astronomy at Swarthmore College
... Magnetic massive stars have harder spectra with narrower lines and rotationally modulated variability, in general agreement with MHD simulations. Line ratio diagnostics are useful for localizing the hot plasma, and indicate that the MHD simulations predict a location that is too far from the photosp ...
... Magnetic massive stars have harder spectra with narrower lines and rotationally modulated variability, in general agreement with MHD simulations. Line ratio diagnostics are useful for localizing the hot plasma, and indicate that the MHD simulations predict a location that is too far from the photosp ...
Jets from Black Holes in Quasars
... I get energized with a shock wave, I get turbulent inside, The magnetic propulsion just can't be denied ...
... I get energized with a shock wave, I get turbulent inside, The magnetic propulsion just can't be denied ...
N Brickhouse
... Collisionally Ionized Plasmas and Their X-ray Spectra • ATOMDB (Smith et al. 2001; Foster et al. 2012) • Collisionally ionized X-ray sources include: - Hot gas in galaxies - Hot gas in clusters of galaxies - Hot gas in the interstellar medium - Ejecta and shocks in supernova remnants - Shocks in ho ...
... Collisionally Ionized Plasmas and Their X-ray Spectra • ATOMDB (Smith et al. 2001; Foster et al. 2012) • Collisionally ionized X-ray sources include: - Hot gas in galaxies - Hot gas in clusters of galaxies - Hot gas in the interstellar medium - Ejecta and shocks in supernova remnants - Shocks in ho ...
Paper (pdf)
... the neutron star rotation and magnetic field axes and constrain the mass to radius ratio. This project has been selected for technology development funding by the NASA Explorer Program. Keywords: Polarimetry, X-rays, Telescopes ...
... the neutron star rotation and magnetic field axes and constrain the mass to radius ratio. This project has been selected for technology development funding by the NASA Explorer Program. Keywords: Polarimetry, X-rays, Telescopes ...
proposed research projects for pparc gemini studentships
... properties (masses and dynamics). GEMINI spectroscopy will allow us to measure kinematics and line strengths out to large radii. We will combine this information with available HST photometry and analyse it using detailed dynamical and stellar population models. Existing data already hint at interes ...
... properties (masses and dynamics). GEMINI spectroscopy will allow us to measure kinematics and line strengths out to large radii. We will combine this information with available HST photometry and analyse it using detailed dynamical and stellar population models. Existing data already hint at interes ...
Document
... 3. Globular cluster cores in our Milky Way and Andromeda 4. Possible IMBH near the center of the Milky Way 5.Low-luminosity Hard X-ray/radio sources in the galactic bulge and other population II systems ...
... 3. Globular cluster cores in our Milky Way and Andromeda 4. Possible IMBH near the center of the Milky Way 5.Low-luminosity Hard X-ray/radio sources in the galactic bulge and other population II systems ...
SSS in young stellar populations: progenitors of the
... it accretes critical mass from Be disk • WDs could experience accretion and outburst cycles like in novae, and possible gain in mass with time • WDs initially massive, so require less mass to reach MCh • Mass accretion can be more efficient if binary orbit and disk are coplanar • Models predict CO w ...
... it accretes critical mass from Be disk • WDs could experience accretion and outburst cycles like in novae, and possible gain in mass with time • WDs initially massive, so require less mass to reach MCh • Mass accretion can be more efficient if binary orbit and disk are coplanar • Models predict CO w ...
Chandra Observation of Pulsar Wind Nebula
... The orbital period of the progenitor binary system is about a few days, and the separation of the two component stars is about 1/10 of the distance from the Earth to the Sun. ...
... The orbital period of the progenitor binary system is about a few days, and the separation of the two component stars is about 1/10 of the distance from the Earth to the Sun. ...
Frequency x Energy Spectral fitting is degenerate : timing
... •The position of νb is determined from simulating the full PDS and indicates that the position of the QPO does not appear to agree with the tight correlation seen in binaries. •If the amount of variability (and X-ray spectrum) is indicative of Eddington/super-Eddington accretion then perhaps the QPO ...
... •The position of νb is determined from simulating the full PDS and indicates that the position of the QPO does not appear to agree with the tight correlation seen in binaries. •If the amount of variability (and X-ray spectrum) is indicative of Eddington/super-Eddington accretion then perhaps the QPO ...
The coronal temperatures of low-mass main
... threshold in rotation, given that saturation happens at a single mass-independent value of RX . It would further imply that all saturated stars have similar coronal temperatures. On the other hand, if either LX or FX are the relevant parameters, then it would indicate that among stars that lie above ...
... threshold in rotation, given that saturation happens at a single mass-independent value of RX . It would further imply that all saturated stars have similar coronal temperatures. On the other hand, if either LX or FX are the relevant parameters, then it would indicate that among stars that lie above ...
X-ray astronomy
X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites. X-ray astronomy is the space science related to a type of space telescope that can see farther than standard light-absorption telescopes, such as the Mauna Kea Observatories, via x-ray radiation.X-ray emission is expected from astronomical objects that contain extremely hot gasses at temperatures from about a million kelvin (K) to hundreds of millions of kelvin (MK). Although X-rays have been observed emanating from the Sun since the 1940s, the discovery in 1962 of the first cosmic X-ray source was a surprise. This source is called Scorpius X-1 (Sco X-1), the first X-ray source found in the constellation Scorpius. The X-ray emission of Scorpius X-1 is 10,000 times greater than its visual emission, whereas that of the Sun is about a million times less. In addition, the energy output in X-rays is 100,000 times greater than the total emission of the Sun in all wavelengths. Based on discoveries in this new field of X-ray astronomy, starting with Scorpius X-1, Riccardo Giacconi received the Nobel Prize in Physics in 2002. It is now known that such X-ray sources as Sco X-1 are compact stars, such as neutron stars or black holes. Material falling into a black hole may emit X-rays, but the black hole itself does not. The energy source for the X-ray emission is gravity. Infalling gas and dust is heated by the strong gravitational fields of these and other celestial objects.Many thousands of X-ray sources are known. In addition, the space between galaxies in galaxy clusters is filled with a very hot, but very dilute gas at a temperature between 10 and 100 megakelvins (MK). The total amount of hot gas is five to ten times the total mass in the visible galaxies.