THE STAR FORMATION AND NUCLEAR ACCRETION HISTORIES OF NORMAL GALAXIES
... dominated by star formation, while that from early-type galaxies is dominated by a combination of hot gas and active galactic nucleus (AGN) emission. We find that the mean star formation and supermassive black hole accretion rate densities evolve like ∼ (1+z)3±1 , in agreement with the trends found ...
... dominated by star formation, while that from early-type galaxies is dominated by a combination of hot gas and active galactic nucleus (AGN) emission. We find that the mean star formation and supermassive black hole accretion rate densities evolve like ∼ (1+z)3±1 , in agreement with the trends found ...
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 ...
SAGE_prop
... Mullard Space Science Laboratory (UK) and the Lawrence Livermore National Laboratory (USA). A flight of NASA rocket 36.195 in February 2001 yielded a high resolution EUV spectrum of the white dwarf G191-B2B, the first such data for any astronomical object other than the Sun, and demonstrated the cap ...
... Mullard Space Science Laboratory (UK) and the Lawrence Livermore National Laboratory (USA). A flight of NASA rocket 36.195 in February 2001 yielded a high resolution EUV spectrum of the white dwarf G191-B2B, the first such data for any astronomical object other than the Sun, and demonstrated the cap ...
Starburst Galaxies Under the Microscope: High
... Also commonly detected are the rovibrational lines of H2. Arising from levels about 6 000 K above the ground state, these lines trace hot molecular gas. While the diagnostic use of these lines is complicated by the fact that multiple excitation mechanisms can play a role (and probably do play a role ...
... Also commonly detected are the rovibrational lines of H2. Arising from levels about 6 000 K above the ground state, these lines trace hot molecular gas. While the diagnostic use of these lines is complicated by the fact that multiple excitation mechanisms can play a role (and probably do play a role ...
PDF only - at www.arxiv.org.
... The nearby (z = 0.184) radio-quiet quasar PDS 456 is an established Rosetta stone for studying disk winds (6–8). With a bolometric luminosity Lbol ~ 1047 erg/s, and a mass of the central black hole on the order of 109 solar masses (Msun) (9), it is an exceptionally luminous AGN in the local universe ...
... The nearby (z = 0.184) radio-quiet quasar PDS 456 is an established Rosetta stone for studying disk winds (6–8). With a bolometric luminosity Lbol ~ 1047 erg/s, and a mass of the central black hole on the order of 109 solar masses (Msun) (9), it is an exceptionally luminous AGN in the local universe ...
FERMI GBM detections of four AXPs at soft gamma-rays
... SWIFT SWIFT gamma-ray burst mission XRT X-Ray Telescope ...
... SWIFT SWIFT gamma-ray burst mission XRT X-Ray Telescope ...
VLT observations of GRS 1915+ 105
... absolute calibration could be performed. This is because HIP 99727 does not have yet K-band magnitudes available in the literature. Nevertheless, a relative comparison of the continuum level and line fluxes can actually be obtained. During the second epoch, the continuum was ∼ 6% brighter than durin ...
... absolute calibration could be performed. This is because HIP 99727 does not have yet K-band magnitudes available in the literature. Nevertheless, a relative comparison of the continuum level and line fluxes can actually be obtained. During the second epoch, the continuum was ∼ 6% brighter than durin ...
High-Energy Emission from the PSR B1259
... 69 ms X-ray pulsar A0538-66 in the LMC which occasionally accretes with an X-ray luminosity near the Eddington limit LE ∼ 1038 erg s−1 (Skinner et al. 1982). (2) Propeller effect emission, caused by gaseous material being temporarily trapped between the light cylinder and corotation radius of the pu ...
... 69 ms X-ray pulsar A0538-66 in the LMC which occasionally accretes with an X-ray luminosity near the Eddington limit LE ∼ 1038 erg s−1 (Skinner et al. 1982). (2) Propeller effect emission, caused by gaseous material being temporarily trapped between the light cylinder and corotation radius of the pu ...
pdf
... A general, insightful, and useful introduction to X-ray imaging systems and zone plates is given by Spiller.6 The specific status of diffractive optics for X-rays is reviewed by Michette11 where the use of zone plates for microscopy is emphasized. He points out the use of a central stop and axial ap ...
... A general, insightful, and useful introduction to X-ray imaging systems and zone plates is given by Spiller.6 The specific status of diffractive optics for X-rays is reviewed by Michette11 where the use of zone plates for microscopy is emphasized. He points out the use of a central stop and axial ap ...
Annual report 2004 - Département d`Astrophysique, Géophysique et
... In the framework of a long-term spectroscopic and photometric monitoring of slowly pulsating B stars we studied thoroughly the northern target star HD 147394. We performed an end-to-end analysis, consisting of a frequency analysis, a mode identification from line-profile variations and a comparison ...
... In the framework of a long-term spectroscopic and photometric monitoring of slowly pulsating B stars we studied thoroughly the northern target star HD 147394. We performed an end-to-end analysis, consisting of a frequency analysis, a mode identification from line-profile variations and a comparison ...
Title The Correlation between Dispersion Measure and X
... are found in the hot phase of the ISM, including H ii regions ionized by UV radiation from hot O or B type stars and the shock-heated interior of supernova remnants (SNRs). These sources can contribute significant DM up to a few hundred parsecs per cubic centimeter. At X-ray energies, photons are ab ...
... are found in the hot phase of the ISM, including H ii regions ionized by UV radiation from hot O or B type stars and the shock-heated interior of supernova remnants (SNRs). These sources can contribute significant DM up to a few hundred parsecs per cubic centimeter. At X-ray energies, photons are ab ...
Document
... (NS-BH) in a binary system will loose energy through gravitational waves • The 2 objects will get closer until tidal forces rip the NS apart and matter falls into a BH. • The process has ms timescale • Evidence for the merger model are less striking: ...
... (NS-BH) in a binary system will loose energy through gravitational waves • The 2 objects will get closer until tidal forces rip the NS apart and matter falls into a BH. • The process has ms timescale • Evidence for the merger model are less striking: ...
1e 1048.1−5937, xte j1810−197 and 4u 0142+61
... line center and black body temperatures) are given in Table 1. What is remarkable is that in each case, 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 ...
... line center and black body temperatures) are given in Table 1. What is remarkable is that in each case, 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 ...
The X-ray/radio and UV luminosity expected from symbiotic systems
... Context. Symbiotic systems (i.e. a white dwarf + red giant star, WD + RG), which experience mass loss and form circumstellar material (CSM), have been suggested as being a possible progenitor system of type Ia supernovae (SNe Ia). After a supernova explosion, the supernova ejecta may interact with t ...
... Context. Symbiotic systems (i.e. a white dwarf + red giant star, WD + RG), which experience mass loss and form circumstellar material (CSM), have been suggested as being a possible progenitor system of type Ia supernovae (SNe Ia). After a supernova explosion, the supernova ejecta may interact with t ...
SOLAR HARD X-RAY AND GAMMA-RAY OBSERVATIONS FROM
... The first part of the review is devoted to the constraints obtained on the electron acceleration timescale through the analysis of the temporal characteristics of the bursts. Combined studies of hard X-ray and gamma-ray emissions from PHEBUS and radio emissions from the Nancay Multifrequency Radiohe ...
... The first part of the review is devoted to the constraints obtained on the electron acceleration timescale through the analysis of the temporal characteristics of the bursts. Combined studies of hard X-ray and gamma-ray emissions from PHEBUS and radio emissions from the Nancay Multifrequency Radiohe ...
Spacecraft Navigation Using X-Ray Pulsars
... orbiting spacecraft based on radio signals from a pulsar.35 However, both the radio and optical signatures from pulsars have limitations that reduce their effectiveness for spacecraft navigation. At the radio frequencies that pulsars emit (∼100 MHz to a few gigahertz) and with their faint emissions, ...
... orbiting spacecraft based on radio signals from a pulsar.35 However, both the radio and optical signatures from pulsars have limitations that reduce their effectiveness for spacecraft navigation. At the radio frequencies that pulsars emit (∼100 MHz to a few gigahertz) and with their faint emissions, ...
Publications 2003 - Département d`Astrophysique, Géophysique et
... description of the eigenfunctions in the star atmosphere. Numerous theoretical models have been computed in order to select the best model fitting the observed frequency values as well as the mode identifications. The derived mass is 9.62 solar masses with an age of 15.7 million years. ...
... description of the eigenfunctions in the star atmosphere. Numerous theoretical models have been computed in order to select the best model fitting the observed frequency values as well as the mode identifications. The derived mass is 9.62 solar masses with an age of 15.7 million years. ...
FRA2015_mmMM_Junzhi_Wang
... • First mega-maser:Water in NGC4945, 1975, nature • OH in Arp220, 1982, ApJL, and H2CO in Arp220, 1986, ApJ • Many searching projects of new mega-masers had been done in past 30 years, mainly focus on class II CH3OH megamasers, without success • Water mega-masers had been used to study the central s ...
... • First mega-maser:Water in NGC4945, 1975, nature • OH in Arp220, 1982, ApJL, and H2CO in Arp220, 1986, ApJ • Many searching projects of new mega-masers had been done in past 30 years, mainly focus on class II CH3OH megamasers, without success • Water mega-masers had been used to study the central s ...
5 Report of the Panel on Stars and Stellar Evolution
... The science frontier for stars and stellar evolution is as close as the Sun and as distant as exploding stars at redshift 8.3. It includes understanding processes of exquisite complexity that connect the rotation of stars with their magnetic fields and areas of nearly total ignorance about phenomena ...
... The science frontier for stars and stellar evolution is as close as the Sun and as distant as exploding stars at redshift 8.3. It includes understanding processes of exquisite complexity that connect the rotation of stars with their magnetic fields and areas of nearly total ignorance about phenomena ...
What caused the GeV flare of PSR B1259-63?
... star during the GeV flare (Fig. 1). Indeed, the radio pulsations, eclipsed by the circumstellar material starting at τ − 16 d, turn back on two weeks prior to the GeV flare (Abdo et al. 2011). Hence, the mechanism for the GeV flare also appears distinct from that causing the radio/X-ray variability. ...
... star during the GeV flare (Fig. 1). Indeed, the radio pulsations, eclipsed by the circumstellar material starting at τ − 16 d, turn back on two weeks prior to the GeV flare (Abdo et al. 2011). Hence, the mechanism for the GeV flare also appears distinct from that causing the radio/X-ray variability. ...
space telescope imaging spectrograph survey of far
... case of the dM3e flare star AD Leonis, based on a multiwavelength flare campaign in 2000 March by S. Hawley and collaborators in which 52 ks of exposure in the STIS mediumresolution echelle mode was obtained (see Allred et al. 2002). The coronal features are weak compared with neighboring low-excitati ...
... case of the dM3e flare star AD Leonis, based on a multiwavelength flare campaign in 2000 March by S. Hawley and collaborators in which 52 ks of exposure in the STIS mediumresolution echelle mode was obtained (see Allred et al. 2002). The coronal features are weak compared with neighboring low-excitati ...
MULTI-FREQUENCY TIME VARIABILITY OF ACTIVE GALACTIC NUCLEI RITABAN CHATTERJEE
... the accretion of matter onto a supermassive black hole (1 million - 10 billion solar masses). In many cases AGNs produce two oppositely directed jets of magnetized plasma moving at near-light speed that are luminous over a large range of wavelengths. Understanding the structure and ongoing physical ...
... the accretion of matter onto a supermassive black hole (1 million - 10 billion solar masses). In many cases AGNs produce two oppositely directed jets of magnetized plasma moving at near-light speed that are luminous over a large range of wavelengths. Understanding the structure and ongoing physical ...
The Swift satellite lives up to its name, revealing cosmic
... e.g. Nakar 2007 for a review). Given that a large fraction of stars in our Universe are thought to exist in pairs, orbiting each other in a binary system, a double-star merger seems like a disaster waiting to happen in every corner of the Universe. However for a powerful GRB to be produced these sta ...
... e.g. Nakar 2007 for a review). Given that a large fraction of stars in our Universe are thought to exist in pairs, orbiting each other in a binary system, a double-star merger seems like a disaster waiting to happen in every corner of the Universe. However for a powerful GRB to be produced these sta ...
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.