Chandra News The Secret X-ray Lives of Planetary Nebulae
... To investigate this scenario, we performed a Chandra pilot study of two PCEB central stars, and found that both displayed X-ray emission consistent with highly magnetically active companions (Montez et al. 2010). Combined with the serendipitous detection of hard X-rays from the central star within L ...
... To investigate this scenario, we performed a Chandra pilot study of two PCEB central stars, and found that both displayed X-ray emission consistent with highly magnetically active companions (Montez et al. 2010). Combined with the serendipitous detection of hard X-rays from the central star within L ...
Dynamical properties of a large young disk galaxy at z=2.03⋆
... More than 30 years after the first publication of what is now known as the Tully-Fisher relation (TFR) (Tully & Fisher 1977), the origin of the TFR is still subject of debate. Some authors explain the TFR as a consequence of self-regulated star formation in disks with different masses (e.g. Silk 199 ...
... More than 30 years after the first publication of what is now known as the Tully-Fisher relation (TFR) (Tully & Fisher 1977), the origin of the TFR is still subject of debate. Some authors explain the TFR as a consequence of self-regulated star formation in disks with different masses (e.g. Silk 199 ...
Phase-resolved high-resolution spectrophotometry of the eclipsing
... a ballistic trajectory and later governed by the magnetic field, which leads the matter along magnetic field lines to the polar regions of the white dwarf. Most of the gravitational energy is released there, although some dissipative energy loss is expected to occur all along the stream, in particul ...
... a ballistic trajectory and later governed by the magnetic field, which leads the matter along magnetic field lines to the polar regions of the white dwarf. Most of the gravitational energy is released there, although some dissipative energy loss is expected to occur all along the stream, in particul ...
ALMA Science Results
... – 16:35 - 16:50 ALMA and VLA measurements of frequencydependent time lags in Sgr A*: evidence for a relativistic outflow • Christiaan Brinkerink, IMAPP, Radboud University Nijmegen – What is SgrA* exactly?? Accretion flow? Jet? SED appears partially self-absorbed synchrotron. Usually this type has ...
... – 16:35 - 16:50 ALMA and VLA measurements of frequencydependent time lags in Sgr A*: evidence for a relativistic outflow • Christiaan Brinkerink, IMAPP, Radboud University Nijmegen – What is SgrA* exactly?? Accretion flow? Jet? SED appears partially self-absorbed synchrotron. Usually this type has ...
The physics of star formation
... of their high opacity, the rate at which they are heated by external radiation is low; the result is that molecular clouds are very cold and have typical temperatures of only about 10–20 K. Higher temperatures of up to 100 K or more may exist locally in regions heated by luminous newly formed stars. ...
... of their high opacity, the rate at which they are heated by external radiation is low; the result is that molecular clouds are very cold and have typical temperatures of only about 10–20 K. Higher temperatures of up to 100 K or more may exist locally in regions heated by luminous newly formed stars. ...
The physics of star formation - Yale Astronomy
... Stars are the fundamental units of luminous matter in the universe, and they are responsible, directly or indirectly, for most of what we see when we observe it. They also serve as our primary tracers of the structure and evolution of the universe and its contents. Consequently, it is of central imp ...
... Stars are the fundamental units of luminous matter in the universe, and they are responsible, directly or indirectly, for most of what we see when we observe it. They also serve as our primary tracers of the structure and evolution of the universe and its contents. Consequently, it is of central imp ...
Superbubble Activity in Star-Forming Galaxies M. S. Oey
... remain consistent with Lx predicted by the adiabatic model. It will thus be of great interest to determine Lx for these objects with XMMNewton or Chandra. Also, an interface region between the hot gas and cooler shells should generate intermediate temperatures and ions. Chu et al. (1994) searched a ...
... remain consistent with Lx predicted by the adiabatic model. It will thus be of great interest to determine Lx for these objects with XMMNewton or Chandra. Also, an interface region between the hot gas and cooler shells should generate intermediate temperatures and ions. Chu et al. (1994) searched a ...
Homologous Stars: Simple Scaling Relations
... of a planet like Earth. The case n = 5 is also special, as the radius of this ”star” is infinite. It is possible to show that all polytropes with n > 5 have infinite radii. This means that only solutions with n < 5 have a surface. The two cases most interesting for real stars have n = 1.5 and n = 3, ...
... of a planet like Earth. The case n = 5 is also special, as the radius of this ”star” is infinite. It is possible to show that all polytropes with n > 5 have infinite radii. This means that only solutions with n < 5 have a surface. The two cases most interesting for real stars have n = 1.5 and n = 3, ...
The asymmetric nuclear region of M83 and its off
... field spectroscopic data show the complexity of the inner 330 × 330 pc. The nuclear region reveals a pronounced asymmetry, with the optical peak displaced eastwards from the centre of fainter isophotes, and the main starburst region displaced westwards. We find that Br γ emission from young star clu ...
... field spectroscopic data show the complexity of the inner 330 × 330 pc. The nuclear region reveals a pronounced asymmetry, with the optical peak displaced eastwards from the centre of fainter isophotes, and the main starburst region displaced westwards. We find that Br γ emission from young star clu ...
The Structure and Evolution of Protoplanetary Disks: an Infrared and
... Since the start of Early Science observations in 2011, ALMA is shedding new light on every stage of disk evolution, from the deeply embedded Class I stage† to the dissipation of the primordial disk and the transition to the debris disk phase. In the following, we highlight some of remarkable ALMA Ea ...
... Since the start of Early Science observations in 2011, ALMA is shedding new light on every stage of disk evolution, from the deeply embedded Class I stage† to the dissipation of the primordial disk and the transition to the debris disk phase. In the following, we highlight some of remarkable ALMA Ea ...
Annual Report 2006/2007
... supernova remnant Cassiopeia A (Cas A). This object is the brightest radio source in the sky, and has been created by a supernova explosion about 330 year ago. The star itself had a mass of around 20 times the mass of the sun, but by the time it exploded it must have lost most of the outer layers. T ...
... supernova remnant Cassiopeia A (Cas A). This object is the brightest radio source in the sky, and has been created by a supernova explosion about 330 year ago. The star itself had a mass of around 20 times the mass of the sun, but by the time it exploded it must have lost most of the outer layers. T ...
Word version - White dwarf stars and the Chandrasekhar limit
... and others. Sommerfeld left Chandra with some unpublished material of his, on the theory of electrons in metals. Chandra immediately launched into a study of the new material. In a few months Chandra had written a paper of his own, The Compton Scattering and the New Statistics. He felt that the pape ...
... and others. Sommerfeld left Chandra with some unpublished material of his, on the theory of electrons in metals. Chandra immediately launched into a study of the new material. In a few months Chandra had written a paper of his own, The Compton Scattering and the New Statistics. He felt that the pape ...
Evolved, single, slowly rotating... but magnetically active
... level of magnetic activity. New BVRI photometry from two robotic telescopes from 1991 through 1998 together with previously published photometric data gives a very precise photometric period of 306.9±0.4 days. With the aid of high-resolution (R=120,000) optical spectra and the Hipparcos parallax we ...
... level of magnetic activity. New BVRI photometry from two robotic telescopes from 1991 through 1998 together with previously published photometric data gives a very precise photometric period of 306.9±0.4 days. With the aid of high-resolution (R=120,000) optical spectra and the Hipparcos parallax we ...
galaxy formation with cold gas accretion and evolving stellar initial
... by Cole et al. (2001) is duplicated in each plot by the gray solid line, and the black and color lines are our model predictions. First, it is clear that while the data are consistent at the massive end, the measurements differ by a factor of ∼2–3 for galaxies with mass below 1010.5 M . This is mai ...
... by Cole et al. (2001) is duplicated in each plot by the gray solid line, and the black and color lines are our model predictions. First, it is clear that while the data are consistent at the massive end, the measurements differ by a factor of ∼2–3 for galaxies with mass below 1010.5 M . This is mai ...
thick disk - asteroSTEP
... How to test between these possibilities for thick disk formation ? Sales et al (2009) looked at the expected orbital eccentricity distribution for thick disk stars in different formation scenarios. Their four scenarios are: • a gas-rich merger (Brook et al 2004, 2005). The thick disk stars are born ...
... How to test between these possibilities for thick disk formation ? Sales et al (2009) looked at the expected orbital eccentricity distribution for thick disk stars in different formation scenarios. Their four scenarios are: • a gas-rich merger (Brook et al 2004, 2005). The thick disk stars are born ...
Planet transit and stellar granulation detection with interferometry
... of an observer on Earth) depend on the planet’s mass and the inclination of its orbit to our line of sight. Measurements of the Doppler-shifted spectra give a minimum value for the mass of the planet. A potential complication to planet detection, however, may be caused by stellar surface inhomogenei ...
... of an observer on Earth) depend on the planet’s mass and the inclination of its orbit to our line of sight. Measurements of the Doppler-shifted spectra give a minimum value for the mass of the planet. A potential complication to planet detection, however, may be caused by stellar surface inhomogenei ...
Giant Planet Formation, Evolution, and Internal Structure
... to explain the properties of those planets and their particular characteristics. The detections of giant planets outside the Solar System have led to the discovery of a rich and diverse population of giant exoplanets, many of which have measured radii and masses. Clues on the nature of giant planet ...
... to explain the properties of those planets and their particular characteristics. The detections of giant planets outside the Solar System have led to the discovery of a rich and diverse population of giant exoplanets, many of which have measured radii and masses. Clues on the nature of giant planet ...
From: BXSVR0::OWOCKI 12-JAN-2001 10:16:41.12 To: DCOHEN
... optically thick line effects you were able to get more symmetric profiles. By my understanding, line optical depth effects might influence the details of the *angular* emission, through the escape probability. But it should only broaden the emission by the Doppler width assumed in your Sobolev treat ...
... optically thick line effects you were able to get more symmetric profiles. By my understanding, line optical depth effects might influence the details of the *angular* emission, through the escape probability. But it should only broaden the emission by the Doppler width assumed in your Sobolev treat ...
The ultracompact nature of the black hole candidate X
... found 9 X-ray sources within the cluster, and identified X9 as the counterpart for 1E 0021.8-7221 (Verbunt & Hasinger 1998, who argued, presciently, that X9 was likely a low-mass X-ray binary). The association of V1 and X9 was later confirmed by Chandra observations (Grindlay et al. 2001). X9 showed ...
... found 9 X-ray sources within the cluster, and identified X9 as the counterpart for 1E 0021.8-7221 (Verbunt & Hasinger 1998, who argued, presciently, that X9 was likely a low-mass X-ray binary). The association of V1 and X9 was later confirmed by Chandra observations (Grindlay et al. 2001). X9 showed ...
The Debris Disk of Solar Analogue $\ tau $ Ceti: Herschel
... The appearance of excess emission in the SED suggests that τ Ceti is indeed surrounded by cooler dust. The narrow wavelength range of the detected excess and the lack of widely extended PACS emission, however, put constraints on the location of this dust. On one hand, the fact that the excess is see ...
... The appearance of excess emission in the SED suggests that τ Ceti is indeed surrounded by cooler dust. The narrow wavelength range of the detected excess and the lack of widely extended PACS emission, however, put constraints on the location of this dust. On one hand, the fact that the excess is see ...
Document
... • Rotating to drive a pair of jet along the rotation axis • Low-metallicity to retain mass an angular momentum SASS ...
... • Rotating to drive a pair of jet along the rotation axis • Low-metallicity to retain mass an angular momentum SASS ...
Cygnus X-1
Cygnus X-1 (abbreviated Cyg X-1) is a well-known galactic X-ray source, thought to be a black hole, in the constellation Cygnus. It was discovered in 1964 during a rocket flight and is one of the strongest X-ray sources seen from Earth, producing a peak X-ray flux density of 6977229999999999999♠2.3×10−23 Wm−2 Hz−1 (7003230000000000000♠2.3×103 Jansky). Cygnus X-1 was the first X-ray source widely accepted to be a black hole and it remains among the most studied astronomical objects in its class. The compact object is now estimated to have a mass about 14.8 times the mass of the Sun and has been shown to be too small to be any known kind of normal star, or other likely object besides a black hole. If so, the radius of its event horizon is about 7004440000000000000♠44 km.Cygnus X-1 belongs to a high-mass X-ray binary system about 7019574266339685654♠6070 ly from the Sun that includes a blue supergiant variable star designated HDE 226868 which it orbits at about 0.2 AU, or 20% of the distance from the Earth to the Sun. A stellar wind from the star provides material for an accretion disk around the X-ray source. Matter in the inner disk is heated to millions of degrees, generating the observed X-rays. A pair of jets, arranged perpendicular to the disk, are carrying part of the energy of the infalling material away into interstellar space.This system may belong to a stellar association called Cygnus OB3, which would mean that Cygnus X-1 is about five million years old and formed from a progenitor star that had more than 7001400000000000000♠40 solar masses. The majority of the star's mass was shed, most likely as a stellar wind. If this star had then exploded as a supernova, the resulting force would most likely have ejected the remnant from the system. Hence the star may have instead collapsed directly into a black hole.Cygnus X-1 was the subject of a friendly scientific wager between physicists Stephen Hawking and Kip Thorne in 1975, with Hawking betting that it was not a black hole. He conceded the bet in 1990 after observational data had strengthened the case that there was indeed a black hole in the system. This hypothesis has not been confirmed due to a lack of direct observation but has generally been accepted from indirect evidence.