Chandra News March 2005 Published by the Chandra X-ray Center (CXC)
... 1979, the first Einstein observation of this region showed that this source was the Carina Nebula, over 1 degree in extent - a bright (by present standards) diffuse source sprinkled with dozens of point-like O stars. Although η Carinae itself is the brightest of these, it accounts for only 6% of the ...
... 1979, the first Einstein observation of this region showed that this source was the Carina Nebula, over 1 degree in extent - a bright (by present standards) diffuse source sprinkled with dozens of point-like O stars. Although η Carinae itself is the brightest of these, it accounts for only 6% of the ...
Galaxy evolution: A new version of the Besançon Maria A. Czekaj
... construction of a new version of the model, which would be able to handle variations of the SFR, IMF, evolutionary tracks, atmosphere models among others (see chapters 3 and 5). When the evolutionary parameters are being changed one must repeat the process of accomplishing the dynamical self-consist ...
... construction of a new version of the model, which would be able to handle variations of the SFR, IMF, evolutionary tracks, atmosphere models among others (see chapters 3 and 5). When the evolutionary parameters are being changed one must repeat the process of accomplishing the dynamical self-consist ...
submillimeter observations of giant molecular clouds in the large
... studies revealed the three types of GMCs in terms of star formation activities; type I is starless, type II is with H ii regions only, and type III is associated with active star formation indicated by huge H ii regions and young star clusters, where the stars identified are only O stars due to the ...
... studies revealed the three types of GMCs in terms of star formation activities; type I is starless, type II is with H ii regions only, and type III is associated with active star formation indicated by huge H ii regions and young star clusters, where the stars identified are only O stars due to the ...
Population effects on the red giant clump absolute magnitude, and
... Udalski and Popowski) are not general. In fact, the distribution of clump stars has several factors hidden in it ± e.g. the age±metallicity relation, the rate of past star formation ± that cannot be described by such relations. The model behaviour is also supported by empirical data for open cluster ...
... Udalski and Popowski) are not general. In fact, the distribution of clump stars has several factors hidden in it ± e.g. the age±metallicity relation, the rate of past star formation ± that cannot be described by such relations. The model behaviour is also supported by empirical data for open cluster ...
Radio pulsars
... than doubled the number of known pulsars • New population of high-B pulsars and new SNR associations • Globular clusters contain many millisecond pulsars • Precision timing of binary millisecond pulsars measures many properties of binary stars and tests general relativity. • Discovery of highly rela ...
... than doubled the number of known pulsars • New population of high-B pulsars and new SNR associations • Globular clusters contain many millisecond pulsars • Precision timing of binary millisecond pulsars measures many properties of binary stars and tests general relativity. • Discovery of highly rela ...
CENTRAL STARS OF PLANETARY NEBULAE IN THE LARGE
... PN typically masks the light of the central star for wavelengths longward of 1215 8 ( Bianchi et al. 1997), complicating the task of characterizing the two components if relying solely on UV and optical data. Characteristics of a large sample of LMC CSPNs have been inferred from photoionization mod ...
... PN typically masks the light of the central star for wavelengths longward of 1215 8 ( Bianchi et al. 1997), complicating the task of characterizing the two components if relying solely on UV and optical data. Characteristics of a large sample of LMC CSPNs have been inferred from photoionization mod ...
Planetary Nebula
... remarkable example of a star going through death throes just as it dramatically transforms itself from a normal red giant star into a planetary nebula. This process happens so quickly that such objects are quite rare, even though astronomers believe that most stars like the Sun will eventually go th ...
... remarkable example of a star going through death throes just as it dramatically transforms itself from a normal red giant star into a planetary nebula. This process happens so quickly that such objects are quite rare, even though astronomers believe that most stars like the Sun will eventually go th ...
Jul y 10-12,
... Almost all Galactic black hole (BH) binaries with low mass donors are transient X-ray sources; we expect most of the X-ray transients (XRTs) observed in external galaxies to be BH binaries also. Obtaining period estimates for extra-galactic XRTs is challenging, but the resulting period distribution ...
... Almost all Galactic black hole (BH) binaries with low mass donors are transient X-ray sources; we expect most of the X-ray transients (XRTs) observed in external galaxies to be BH binaries also. Obtaining period estimates for extra-galactic XRTs is challenging, but the resulting period distribution ...
Multiplicity in Early Stellar Evolution
... Bate, 2009b). The resulting binary statistics are scarcely distinguishable from those in the earlier barotropic calculations and again in good agreement with observations (see Figure 1). Observations of molecular clouds have shown that magnetic fields are generally more dynamically important than tu ...
... Bate, 2009b). The resulting binary statistics are scarcely distinguishable from those in the earlier barotropic calculations and again in good agreement with observations (see Figure 1). Observations of molecular clouds have shown that magnetic fields are generally more dynamically important than tu ...
The Emission Line Spectrum of Active Galactic
... (H I, He I λλ5876,6678,7065, He II λ4686 and Fe II in the visible domain). The narrow-line spectra of Seyfert 1s are very similar to those of Seyfert 2s; there are however significant differences, most notably much stronger high- ionization lines ([Fe VII]λ6087, [Fe X]λ6375, [Fe XI]λ7892) in some Se ...
... (H I, He I λλ5876,6678,7065, He II λ4686 and Fe II in the visible domain). The narrow-line spectra of Seyfert 1s are very similar to those of Seyfert 2s; there are however significant differences, most notably much stronger high- ionization lines ([Fe VII]λ6087, [Fe X]λ6375, [Fe XI]λ7892) in some Se ...
Stars, Galaxies, and Beyond
... covers many more topics, is vastly more detailed in what it covers, and is well worth the high price. A 3rd edition would be eagerly received and is needed to incorporate some of the exploding new astronomical knowledge. I also refer occasionally to Burke BF and Graham-Smith F, An Introduction to Ra ...
... covers many more topics, is vastly more detailed in what it covers, and is well worth the high price. A 3rd edition would be eagerly received and is needed to incorporate some of the exploding new astronomical knowledge. I also refer occasionally to Burke BF and Graham-Smith F, An Introduction to Ra ...
Article PDF - IOPscience
... (PS1) 3p survey offers multi-band, multi-epoch, precise photometry across much of the sky, but a robust identification of RR Lyrae stars in this data set poses a challenge, given PS1ʼs sparse, asynchronous multi-band light curves (12 epochs in each of five bands, taken over a 4.5 year period). We pre ...
... (PS1) 3p survey offers multi-band, multi-epoch, precise photometry across much of the sky, but a robust identification of RR Lyrae stars in this data set poses a challenge, given PS1ʼs sparse, asynchronous multi-band light curves (12 epochs in each of five bands, taken over a 4.5 year period). We pre ...
- National Optical Astronomy Observatory
... magnetic field lines unless there was an indirect mechanism for their flow, namely, other materials that are directed by the magnetic field. The data seems to indicate that the mechanism for the nickel’s movement is not the flow of iron directed by the magnetic fields. The nickel displays greater va ...
... magnetic field lines unless there was an indirect mechanism for their flow, namely, other materials that are directed by the magnetic field. The data seems to indicate that the mechanism for the nickel’s movement is not the flow of iron directed by the magnetic fields. The nickel displays greater va ...
Probing nuclear activity versus star formation at z ∼ 0.8 using near
... this is the largest compilation of NIR spectra of active galactic nuclei (AGN) at this redshift. The data were obtained using the multi-object spectroscopic mode of the Long-slit Intermediate Resolution Infrared Spectrograph (LIRIS) at the 4.2 m William Herschel Telescope (WHT). These galaxies are r ...
... this is the largest compilation of NIR spectra of active galactic nuclei (AGN) at this redshift. The data were obtained using the multi-object spectroscopic mode of the Long-slit Intermediate Resolution Infrared Spectrograph (LIRIS) at the 4.2 m William Herschel Telescope (WHT). These galaxies are r ...
ROSAT Ian R. Stevens* and David K. Strickland*
... We note that the detection of a broad He II l4686 feature can be difficult even with high signal-to-noise ratio (S/N) data. This does mean that our sample of WR galaxies will tend to be rather heterogenous. Future studies will have to focus on broader samples of starburst galaxies and starburst regi ...
... We note that the detection of a broad He II l4686 feature can be difficult even with high signal-to-noise ratio (S/N) data. This does mean that our sample of WR galaxies will tend to be rather heterogenous. Future studies will have to focus on broader samples of starburst galaxies and starburst regi ...
Structure in the first quadrant of the Galaxy: an analysis of TMGS star
... limited to single TMGS zones. Consequently, without a detailed prior knowledge of the additional extinction along the specific TMGS lines of sight, it is preferable to model without including these molecular complexes at wavelengths susceptible to appreciable attenuation through clouds of AV . 10 ma ...
... limited to single TMGS zones. Consequently, without a detailed prior knowledge of the additional extinction along the specific TMGS lines of sight, it is preferable to model without including these molecular complexes at wavelengths susceptible to appreciable attenuation through clouds of AV . 10 ma ...
An X-Ray, Optical and Infra-red study of High-Mass X
... First and foremost I would like to thank my supervisor, Malcolm Coe, for his continued guidance and support. His drive to obtain and exploit all manner of data has given me a wealth of information on which to base my thesis and sent me to some of the world’s most incredible places in the process. I ...
... First and foremost I would like to thank my supervisor, Malcolm Coe, for his continued guidance and support. His drive to obtain and exploit all manner of data has given me a wealth of information on which to base my thesis and sent me to some of the world’s most incredible places in the process. I ...
Mass Functions in Fractal Clouds: The Role of Cloud Structure in the
... moving protostars. The simulated clouds that get a normal IMF are not uniform like this. They are always hierarchically structured, or they have a hierarchy of initially converging velocities that lead to hierarchical fragmentation on the same time scale as star formation. The sink particles take ga ...
... moving protostars. The simulated clouds that get a normal IMF are not uniform like this. They are always hierarchically structured, or they have a hierarchy of initially converging velocities that lead to hierarchical fragmentation on the same time scale as star formation. The sink particles take ga ...
6.7 GHz Methanol Masers and the GBT
... compared to OH and H2O masers which are also found towards late type stars/low-mass stars. • What makes the 6.7 GHz line even more interesting is that it traces one of the earliest phases of massive star formation. • A sample of 6.7 GHz methanol masers can thus be used for studying the poorly unders ...
... compared to OH and H2O masers which are also found towards late type stars/low-mass stars. • What makes the 6.7 GHz line even more interesting is that it traces one of the earliest phases of massive star formation. • A sample of 6.7 GHz methanol masers can thus be used for studying the poorly unders ...
Spherical planetary nebulae
... lobes. I assumed in S97 that the progenitors of most of these PNe interacted with a stellar companion via a common envelope phase. (iv) Elliptical PNe. By elliptical alone, I refer to moderate elliptical PNe which show only small departure from sphericity. In S97 the progenitors of these PNe were as ...
... lobes. I assumed in S97 that the progenitors of most of these PNe interacted with a stellar companion via a common envelope phase. (iv) Elliptical PNe. By elliptical alone, I refer to moderate elliptical PNe which show only small departure from sphericity. In S97 the progenitors of these PNe were as ...
The effects of galaxy interactions on star formation
... separate projects. In the first two projects, we examine enhanced star formation by studying the star cluster populations of the interacting galaxies Arp 284 (NGC 7714/5) and Arp 261, using data from the Hubble Space Telescope along with ancillary data from the Spitzer Space Telescope and Galaxy Evo ...
... separate projects. In the first two projects, we examine enhanced star formation by studying the star cluster populations of the interacting galaxies Arp 284 (NGC 7714/5) and Arp 261, using data from the Hubble Space Telescope along with ancillary data from the Spitzer Space Telescope and Galaxy Evo ...
Lya escape from z~ 0.03 star-forming galaxies: the dominant role of
... radiation from OB stars. This helps in the interpretation of the observed Lyα properties because we do not need to worry about non-stellar ionizing sources such as active galactic nuclei (AGNs), which account for some of the high Lyα EWs at z > 2 (Charlot & Fall 1993; Zheng et al. 2010), and low-ion ...
... radiation from OB stars. This helps in the interpretation of the observed Lyα properties because we do not need to worry about non-stellar ionizing sources such as active galactic nuclei (AGNs), which account for some of the high Lyα EWs at z > 2 (Charlot & Fall 1993; Zheng et al. 2010), and low-ion ...
The COMPLETE Survey of Outflows in Perseus
... molecular cloud. However, the CO fails as an outflow tracer in regions where there is little molecular gas (i.e., in the outskirts of the cloud), and so molecular outflows give a lower limit on the outflow momentum and energy injection into their (low-density) surroundings. In these low-density regi ...
... molecular cloud. However, the CO fails as an outflow tracer in regions where there is little molecular gas (i.e., in the outskirts of the cloud), and so molecular outflows give a lower limit on the outflow momentum and energy injection into their (low-density) surroundings. In these low-density regi ...
Star Formation in the Orion Nebula II: Gas, Dust, Proplyds and
... Because of the diversity of backgrounds of the contributors to these subjects, there is an overabundance of nomenclatures and methods of indicating positions. In this article we try to use a uniform system of designation of objects and most positions of sources are indicated in 2000.0 coordinates. R ...
... Because of the diversity of backgrounds of the contributors to these subjects, there is an overabundance of nomenclatures and methods of indicating positions. In this article we try to use a uniform system of designation of objects and most positions of sources are indicated in 2000.0 coordinates. R ...
Gamma Ray Bursts
... about distances in the Universe What are nebulas? Galaxies or objects in our Galaxy? ...
... about distances in the Universe What are nebulas? Galaxies or objects in our Galaxy? ...