Astronomy Astrophysics IRAS 18357-0604 – an analogue of the galactic yellow hypergiant
... (Lagadec et al. 2011). Of these, the most compelling case is provided by IRC +10420 due to a N-enriched chemistry, presence of a massive ejection nebula and apparent real time bluewards evolution across the HR diagram (Klochkova et al. 1997; Castro-Carrizo et al. 2007; Oudmaijer 1998). Currently dem ...
... (Lagadec et al. 2011). Of these, the most compelling case is provided by IRC +10420 due to a N-enriched chemistry, presence of a massive ejection nebula and apparent real time bluewards evolution across the HR diagram (Klochkova et al. 1997; Castro-Carrizo et al. 2007; Oudmaijer 1998). Currently dem ...
An Improved Distance and Mass Estimate for Sgr A* from a Multistar
... approach in 2002, it was possible to fit its motion with a Keplerian orbit (Schödel et al. 2002; Ghez et al. 2003). In addition to the mass of the SMBH, stellar orbits with measured radial velocities have been used to determine the distance to the Galactic Center (Ro ; Ghez et al. 2003; Eisenhauer e ...
... approach in 2002, it was possible to fit its motion with a Keplerian orbit (Schödel et al. 2002; Ghez et al. 2003). In addition to the mass of the SMBH, stellar orbits with measured radial velocities have been used to determine the distance to the Galactic Center (Ro ; Ghez et al. 2003; Eisenhauer e ...
JENAM-2011 Book of abstracts
... that the cosmos was not limited to the Milky Way. At the same epoch, the extraordinary coincidence of the discovery of the Hubble law and of the emergence of General Relativity allowed Cosmology to become a scientific domain, and later Extragalactic Astronomy became a part of Cosmology. Incredible pr ...
... that the cosmos was not limited to the Milky Way. At the same epoch, the extraordinary coincidence of the discovery of the Hubble law and of the emergence of General Relativity allowed Cosmology to become a scientific domain, and later Extragalactic Astronomy became a part of Cosmology. Incredible pr ...
The Multitude of Molecular Hydrogen Knots in the Helix Nebula 1
... in radial distance, 1 & 2 and 4 & 5, are offset in their optical line emissions because they are located at very different azimuthal positions and the nebula has a distinct variation with azimuthal angle. Interestingly, the H2 emission does not appear to have offsets in emission in the overlap regio ...
... in radial distance, 1 & 2 and 4 & 5, are offset in their optical line emissions because they are located at very different azimuthal positions and the nebula has a distinct variation with azimuthal angle. Interestingly, the H2 emission does not appear to have offsets in emission in the overlap regio ...
EROs and submm galaxies: Expectations for FMOS in the
... K20 galaxies have R-K>5 and the average colour is R-K=5.2. ...
... K20 galaxies have R-K>5 and the average colour is R-K=5.2. ...
ROSAT Isolated Neutron Stars
... collapse following a type II supernova explosion Present rate of SN events in the Galaxy: ≈ 0.01/yr (possibly higher in the past) Galactic population of compact objects: ≈ 108 – 109 (≈ 1% of stars) ...
... collapse following a type II supernova explosion Present rate of SN events in the Galaxy: ≈ 0.01/yr (possibly higher in the past) Galactic population of compact objects: ≈ 108 – 109 (≈ 1% of stars) ...
Annual Report 2012 - Max Planck Institute for Astrophysics
... directorship of Ludwig Biermann. It was first es- institution of similar size. tablished as an offshoot of the Max-Planck-Institut In recent years, activities at the MPA have difür Physik, which at that time had just moved from versified. They now address a much broader range Göttingen to Munich. In 19 ...
... directorship of Ludwig Biermann. It was first es- institution of similar size. tablished as an offshoot of the Max-Planck-Institut In recent years, activities at the MPA have difür Physik, which at that time had just moved from versified. They now address a much broader range Göttingen to Munich. In 19 ...
A Method of Correcting Near-Infrared Spectra for Telluric Absorption
... regions of the H lines, the resulting correction template should be more accurate than one based on the G2 V star/solar spectrum ratio alone. Because the normalization process removes the signature of the instrumental throughput from the observed stellar spectra, the object must be flux-calibrated s ...
... regions of the H lines, the resulting correction template should be more accurate than one based on the G2 V star/solar spectrum ratio alone. Because the normalization process removes the signature of the instrumental throughput from the observed stellar spectra, the object must be flux-calibrated s ...
The Ionized Nebula surrounding the Red Supergiant W26 in
... this. While Sher 25 does have two polar outflows, one side is notably brighter than the other, which might suggest that a second outflow exists around W26 but is not detected. Alternatively outflows may exist on both sides of W26 but are only being photoionized on one side by the BSG W26. The possib ...
... this. While Sher 25 does have two polar outflows, one side is notably brighter than the other, which might suggest that a second outflow exists around W26 but is not detected. Alternatively outflows may exist on both sides of W26 but are only being photoionized on one side by the BSG W26. The possib ...
arXiv:astro-ph/0701485v3 15 Jun 2010
... objects) are in a 3:2 resonance, while Jupiter and Saturn are close to a 5:2 mean-motion resonance (known as “the great inequality”) which influences their motion (Lovett, 1895). There are no simple resonances among the major planets. There are, however, many resonant pairs among planetary moons. Ju ...
... objects) are in a 3:2 resonance, while Jupiter and Saturn are close to a 5:2 mean-motion resonance (known as “the great inequality”) which influences their motion (Lovett, 1895). There are no simple resonances among the major planets. There are, however, many resonant pairs among planetary moons. Ju ...
Stellar Structure and Evolution
... given for several years to third-year undergraduate students in physics at the University of Aarhus. The goal of the course and the notes is to show how many aspects of stellar evolution can be understood relatively simply in terms of basic physics. Apart from the intrinsic interest of the topic, th ...
... given for several years to third-year undergraduate students in physics at the University of Aarhus. The goal of the course and the notes is to show how many aspects of stellar evolution can be understood relatively simply in terms of basic physics. Apart from the intrinsic interest of the topic, th ...
radioactive 26a1 in the galaxy: observations versus theory
... discovery of paramount importance [ 27,551: it clearly demonstrates that nucleosynthesis is currently active in the Galaxy and offers an unprecedented opportunity to identify the sites of that activity, as discussed in this article. [Actually, the discovery of radioactive Tc at the surface of S star ...
... discovery of paramount importance [ 27,551: it clearly demonstrates that nucleosynthesis is currently active in the Galaxy and offers an unprecedented opportunity to identify the sites of that activity, as discussed in this article. [Actually, the discovery of radioactive Tc at the surface of S star ...
THE STAR FORMATION AND NUCLEAR ACCRETION HISTORIES OF NORMAL GALAXIES
... Survey (NDWFS), AGN and Galaxy Evolution Survey (AGES), and XBoötes Survey to measure the Xray evolution of 6146 normal galaxies as a function of absolute optical luminosity, redshift, and spectral type over the largely unexplored redshift range 0.1 < ∼z< ∼ 0.5. Because only the closest or brightes ...
... Survey (NDWFS), AGN and Galaxy Evolution Survey (AGES), and XBoötes Survey to measure the Xray evolution of 6146 normal galaxies as a function of absolute optical luminosity, redshift, and spectral type over the largely unexplored redshift range 0.1 < ∼z< ∼ 0.5. Because only the closest or brightes ...
Y.Ueda_Future_HE_Mission2006 - X
... population of Compton thick AGNs in the universe. We have not fully understand the XRB origin yet. The population synthesis model is being almost established below 6-8 keV. However, we have to note that there are a few critical assumptions are made when extrapolating it to above 8 keV. To fully unde ...
... population of Compton thick AGNs in the universe. We have not fully understand the XRB origin yet. The population synthesis model is being almost established below 6-8 keV. However, we have to note that there are a few critical assumptions are made when extrapolating it to above 8 keV. To fully unde ...
Astrospheres and Solar-like Stellar Winds | SpringerLink
... at solar minimum the wind above 30◦ ecliptic latitude is uniformly high speed, low density wind with V ≈ 800 km s−1 (McComas et al., 2000, 2002). This high speed wind originates from coronal holes, which are particularly prominent on the Sun during solar minimum conditions. These solar wind data imp ...
... at solar minimum the wind above 30◦ ecliptic latitude is uniformly high speed, low density wind with V ≈ 800 km s−1 (McComas et al., 2000, 2002). This high speed wind originates from coronal holes, which are particularly prominent on the Sun during solar minimum conditions. These solar wind data imp ...
University of Groningen Photo-ionization studies of nebulae
... correspond to G or F spectral types. The increase in temperature is less than 1 K yr,1 for the 0.565 M and 0.605 M tracks. How does this evolutionary rate compare with the observations? Fernie & Sasselov (1989) calculated the possible increase in temperature for UU Her stars. From the absence of a ...
... correspond to G or F spectral types. The increase in temperature is less than 1 K yr,1 for the 0.565 M and 0.605 M tracks. How does this evolutionary rate compare with the observations? Fernie & Sasselov (1989) calculated the possible increase in temperature for UU Her stars. From the absence of a ...
Astronomy Astrophysics Spectral energy distributions of an AKARI-SDSS-GALEX sample of galaxies
... Context. The nearby universe remains the best laboratory to understand the physical properties of galaxies and is a reference for any comparison with high redshift observations. The all sky (or very large) surveys that have been performed from the ultraviolet (UV) to the far-infrared (far-IR) provid ...
... Context. The nearby universe remains the best laboratory to understand the physical properties of galaxies and is a reference for any comparison with high redshift observations. The all sky (or very large) surveys that have been performed from the ultraviolet (UV) to the far-infrared (far-IR) provid ...
Article PDF - IOPscience
... normal ellipticals; however, disturbed isophotes at the outer edges suggest that a past merger has taken place in all objects (Perlman et al. 2001b). Simulations suggest that the radius of the photometric irregularities determines the timescale since the merger due to virialization of the stellar di ...
... normal ellipticals; however, disturbed isophotes at the outer edges suggest that a past merger has taken place in all objects (Perlman et al. 2001b). Simulations suggest that the radius of the photometric irregularities determines the timescale since the merger due to virialization of the stellar di ...
observations and theory of star cluster formation
... of hierarchical structure. On the largest scale (first level), there is the socalled local arm or Orion-Cygnus spur, which has only young stars (Efremov 1997) and is therefore a sheared star formation feature, not a spiral density wave (Elmegreen and Efremov 1996); in contrast, the SagittariusCarina ...
... of hierarchical structure. On the largest scale (first level), there is the socalled local arm or Orion-Cygnus spur, which has only young stars (Efremov 1997) and is therefore a sheared star formation feature, not a spiral density wave (Elmegreen and Efremov 1996); in contrast, the SagittariusCarina ...
L117 SHOCK-HEATED NH3 IN A MOLECULAR JET ASSOCIATED
... Chièze 1997). It is likely that the observed hot NH3 lies in the oblique part of the working surface where the shock velocity is low. The lack of NH3 emission near the southeast tip of SiO supports this scenario. Toward this region, the NH3 (3, 3) emission appears only toward the rear wings of the ...
... Chièze 1997). It is likely that the observed hot NH3 lies in the oblique part of the working surface where the shock velocity is low. The lack of NH3 emission near the southeast tip of SiO supports this scenario. Toward this region, the NH3 (3, 3) emission appears only toward the rear wings of the ...
POLYTROPES - Princeton
... 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, ...
PDF only - at www.arxiv.org.
... the current techniques for X-ray focusing (to date, adopted only below 10 keV) to the hard (E > 10 keV) X-ray band by adopting very shallow incidence angles (0.1 ÷ 0.4 deg) and graded multilayer coatings5,6. For example, the SIMBOL-X sensitivity band is 0.5 ÷ 80 keV, with a required angular resoluti ...
... the current techniques for X-ray focusing (to date, adopted only below 10 keV) to the hard (E > 10 keV) X-ray band by adopting very shallow incidence angles (0.1 ÷ 0.4 deg) and graded multilayer coatings5,6. For example, the SIMBOL-X sensitivity band is 0.5 ÷ 80 keV, with a required angular resoluti ...
Development of Iodine Cells for the Subaru HDS and the Okayama
... here report on the results of our Doppler measurements of three solar-type stars, 16 Cyg B, τ Cet, and υ And, based on data collected with HDS and HIDES for about one year. These results show that we have achieved a precision of about 5–6 m s−1 over a time span of one year with our current analysis ...
... here report on the results of our Doppler measurements of three solar-type stars, 16 Cyg B, τ Cet, and υ And, based on data collected with HDS and HIDES for about one year. These results show that we have achieved a precision of about 5–6 m s−1 over a time span of one year with our current analysis ...
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.