Chemical abundances and winds of massive stars in M31: a B
... et al. (1996a) investigated the extinction in M31 using the HST/FOS data for OB 10-64 and additional M31 OB stars and concluded that the 2175Å bump is weak or absent in M31. The slope of the extinction curve was consistent with the Galactic curve, but the low reddening of their M31 target stars pre ...
... et al. (1996a) investigated the extinction in M31 using the HST/FOS data for OB 10-64 and additional M31 OB stars and concluded that the 2175Å bump is weak or absent in M31. The slope of the extinction curve was consistent with the Galactic curve, but the low reddening of their M31 target stars pre ...
A Project Underway to Build an Inexpensive 8-Meter Telescope
... The primary challenge is likely to be control of systematic errors. One method of dealing with this might be to split the sample of 100,000 well-sampled light curves into redshift bins (~0.1) small enough that residual error in cosmological parameters are insignificant (see next slide), then perform ...
... The primary challenge is likely to be control of systematic errors. One method of dealing with this might be to split the sample of 100,000 well-sampled light curves into redshift bins (~0.1) small enough that residual error in cosmological parameters are insignificant (see next slide), then perform ...
disappearance of comet c/2010 x1 (elenin): gone with a whimper
... inbound at 4.2 AU, this long-period comet was predicted to become very bright when near perihelion, at 0.48 AU on 2011 September 10. Observations starting 2011 February (heliocentric distance ∼3.5 AU) indeed show the comet to brighten by about 11 mag, with most of the increase occurring inside 1 AU ...
... inbound at 4.2 AU, this long-period comet was predicted to become very bright when near perihelion, at 0.48 AU on 2011 September 10. Observations starting 2011 February (heliocentric distance ∼3.5 AU) indeed show the comet to brighten by about 11 mag, with most of the increase occurring inside 1 AU ...
the Local Group - Simon P Driver
... • to turn a map of the sky into a 3-D picture of the Local Group, we need galaxy distances – Hubble’s law does not apply within the Group because expansion has halted • need to remember that the uncertainty in the distance is ~10% even for bright galaxies – e.g. for the LMC, the range found for ...
... • to turn a map of the sky into a 3-D picture of the Local Group, we need galaxy distances – Hubble’s law does not apply within the Group because expansion has halted • need to remember that the uncertainty in the distance is ~10% even for bright galaxies – e.g. for the LMC, the range found for ...
Archaeoastronomical Study of the Main Pyramids of Giza
... As reported above, an additional anti-clockwise rotation of 15.3˚ is required to overlap the Orion Belt stars on the corresponding pyramids. Actually, such a rotation is necessary since the “axis of the Pyramids” (i.e. the straight line that best fits the positions of the centers, or vertexes, of th ...
... As reported above, an additional anti-clockwise rotation of 15.3˚ is required to overlap the Orion Belt stars on the corresponding pyramids. Actually, such a rotation is necessary since the “axis of the Pyramids” (i.e. the straight line that best fits the positions of the centers, or vertexes, of th ...
Ch17_Galaxies
... dust content and some are more “active” than others • Galaxies tend to cluster together and these clusters appear to be separating from each other, caught up in a Universe that is expanding • The reason for all this diversity is as yet unanswered ...
... dust content and some are more “active” than others • Galaxies tend to cluster together and these clusters appear to be separating from each other, caught up in a Universe that is expanding • The reason for all this diversity is as yet unanswered ...
Article PDF - IOPscience
... RMVS3 integrator in the SWIFT package (Levison & Duncan 1994) with a global time step of 1 yr. To visualize the extent of the scattered disk produced in the above simulations, we have divided the (a, q)-plane into cells and computed the cumulative time spent by each test particle in each cell. The r ...
... RMVS3 integrator in the SWIFT package (Levison & Duncan 1994) with a global time step of 1 yr. To visualize the extent of the scattered disk produced in the above simulations, we have divided the (a, q)-plane into cells and computed the cumulative time spent by each test particle in each cell. The r ...
Planetary Nebulae: Observational Properties, Mimics, and Diagnostics
... Abstract: The total number of true, likely and possible planetary nebulae (PN) now known in the Milky Way is nearly 3000, double the number known a decade ago. The new discoveries are a legacy of the recent availability of wide field, narrowband imaging surveys, primarily in the light of H-alpha. In ...
... Abstract: The total number of true, likely and possible planetary nebulae (PN) now known in the Milky Way is nearly 3000, double the number known a decade ago. The new discoveries are a legacy of the recent availability of wide field, narrowband imaging surveys, primarily in the light of H-alpha. In ...
THE NUCLEUS OF COMET 48P/JOHNSON
... and the median image quality (including effects due to the atmosphere, the telescope optics, and sidereal tracking errors in the telescope) was 0B8 FWHM. The motion of the comet within the 250 s integration period was 0B7 in the February and March data, comparable to the image quality. Experiments ...
... and the median image quality (including effects due to the atmosphere, the telescope optics, and sidereal tracking errors in the telescope) was 0B8 FWHM. The motion of the comet within the 250 s integration period was 0B7 in the February and March data, comparable to the image quality. Experiments ...
M81/M82/NGC3077
... M81 — -35 km/sec (3.63 ± 0.34 Mpc) (CBR value: 48 km/sec) M82 — 202 km/sec (3.9 ± 0.3 Mpc) (CBR value: 296 km/sec) M81 is closer and approaching, while M82 is farther away and receding; ...
... M81 — -35 km/sec (3.63 ± 0.34 Mpc) (CBR value: 48 km/sec) M82 — 202 km/sec (3.9 ± 0.3 Mpc) (CBR value: 296 km/sec) M81 is closer and approaching, while M82 is farther away and receding; ...
Astronomy Astrophysics Circumstellar emission in Be/X-ray binaries of the Magellanic
... need a set of programme stars with well-known distances and interstellar reddenings as well as good determinations of the spectral types. In principle we could choose Be/X-ray binaries in well-studied open clusters and follow an approach similar to the one used by Fabregat & Torrejón (1998). Unfortu ...
... need a set of programme stars with well-known distances and interstellar reddenings as well as good determinations of the spectral types. In principle we could choose Be/X-ray binaries in well-studied open clusters and follow an approach similar to the one used by Fabregat & Torrejón (1998). Unfortu ...
3.1 Radio Astronomy Research Results For much of PY 2010, radio
... that typically contain more than 100 pulse periods. Obviously, pulse amplitudes are highly modulated, with RRATs being extreme cases. So far, PALFA has found 8 objects through the Cornell single-pulse analysis that were missed in the periodicity analysis. Five RRATs have been confirmed through re-ob ...
... that typically contain more than 100 pulse periods. Obviously, pulse amplitudes are highly modulated, with RRATs being extreme cases. So far, PALFA has found 8 objects through the Cornell single-pulse analysis that were missed in the periodicity analysis. Five RRATs have been confirmed through re-ob ...
Chapter 1 The Discovery of Open Clusters - Willmann-Bell
... Often, they are considered to be female and almost always to be seven in number; in many traditions there is also a story about a “lost Pleiad.” It has sometimes been suggested that variability in the shell-star Pleione may account for this latter aspect, but why the number seven should so often be ...
... Often, they are considered to be female and almost always to be seven in number; in many traditions there is also a story about a “lost Pleiad.” It has sometimes been suggested that variability in the shell-star Pleione may account for this latter aspect, but why the number seven should so often be ...
Edwin Hubble (1889
... other, cruder methods to estimate their distances.) Shapley found that the globular clusters are arranged symmetrically around the galaxy, about as many above the plane of the galaxy as below. The clusters seemed to avoid the plane itself, the Milky Way. Shapley wrote that "this great mid-galactic ...
... other, cruder methods to estimate their distances.) Shapley found that the globular clusters are arranged symmetrically around the galaxy, about as many above the plane of the galaxy as below. The clusters seemed to avoid the plane itself, the Milky Way. Shapley wrote that "this great mid-galactic ...
talk
... Dwarfs fainter than MB ~ -14.0 have chaotic velocity fields ??? (e.g. Cote et al. 2000 AJ 120 3027, Lo et al. 1993 AJ 106 507) ...
... Dwarfs fainter than MB ~ -14.0 have chaotic velocity fields ??? (e.g. Cote et al. 2000 AJ 120 3027, Lo et al. 1993 AJ 106 507) ...
observations of white dwarfs in the solar neighborhood
... observed nearly every clear night, generally two per twilight, and a calibration for each observing run (typically of four to six nights) was derived from these. In addition, we observed bright B stars to derive approximate corrections for atmospheric absorption bands. Prior to flux calibration all ...
... observed nearly every clear night, generally two per twilight, and a calibration for each observing run (typically of four to six nights) was derived from these. In addition, we observed bright B stars to derive approximate corrections for atmospheric absorption bands. Prior to flux calibration all ...
Chemical abundances and winds of massive stars in M31: a Btype
... respectively) reflect the reddening from intervening Galactic material. This Milky Way extinction is similar to what we expect for OB 10-64. Using these two stars and OB 10-64, we derive a mean M31 extinction law, which confirms the lack of a 2175-Å feature in M31, similar to the Small Magellanic C ...
... respectively) reflect the reddening from intervening Galactic material. This Milky Way extinction is similar to what we expect for OB 10-64. Using these two stars and OB 10-64, we derive a mean M31 extinction law, which confirms the lack of a 2175-Å feature in M31, similar to the Small Magellanic C ...
Gas fraction and star formation efficiency at z \< 1.0⋆⋆⋆⋆⋆⋆
... After new observations of 39 galaxies at z ∼ 0.6–1.0 obtained at the IRAM 30-m telescope, we present our full CO line survey covering the redshift range 0.2 < z < 1. Our aim is to determine the driving factors accounting for the steep decline in the star formation rate during this epoch. We study bo ...
... After new observations of 39 galaxies at z ∼ 0.6–1.0 obtained at the IRAM 30-m telescope, we present our full CO line survey covering the redshift range 0.2 < z < 1. Our aim is to determine the driving factors accounting for the steep decline in the star formation rate during this epoch. We study bo ...
Statistical analysis of stellar evolution
... its dominant position in a CMD, the evolved red giants, and the even older white dwarfs. Today the physical processes that govern stellar formation and evolution are studied with complex computer models that can be used to predict the plotted magnitudes on a set of CMDs as a function of stellar para ...
... its dominant position in a CMD, the evolved red giants, and the even older white dwarfs. Today the physical processes that govern stellar formation and evolution are studied with complex computer models that can be used to predict the plotted magnitudes on a set of CMDs as a function of stellar para ...
1. INTRODUCTION
... sets with more than 5 days of monitoring or with a signiÐcant number of Ñares (more than ten Ñares identiÐed by eye) were selected. Active coronal sources were our prime choice, as these stars often show several distinct stochastic events. We have focused our analysis on young, active stars that do ...
... sets with more than 5 days of monitoring or with a signiÐcant number of Ñares (more than ten Ñares identiÐed by eye) were selected. Active coronal sources were our prime choice, as these stars often show several distinct stochastic events. We have focused our analysis on young, active stars that do ...
A trip to the end of the universe and the twin “paradox”
... k-calculus1 or the concept of radar time as discussed by Dolby and Gull,2 where hypersurfaces of simultaneity are defined by local measurements of reflected light signals. The interesting information that both twins can interchange in our example are their individual proper times. They will not be a ...
... k-calculus1 or the concept of radar time as discussed by Dolby and Gull,2 where hypersurfaces of simultaneity are defined by local measurements of reflected light signals. The interesting information that both twins can interchange in our example are their individual proper times. They will not be a ...
RApid Temporal Survey-RATS I: Overview and first results
... zenith during the night with about 2 hr spacing. This is done using an algorithm that first places n random fields in the sky in a 5×5 degree box centered around a given pointing. Then a simulated annealing based optimization routine is used to find a combination of n nonoverlapping pointing’s withi ...
... zenith during the night with about 2 hr spacing. This is done using an algorithm that first places n random fields in the sky in a 5×5 degree box centered around a given pointing. Then a simulated annealing based optimization routine is used to find a combination of n nonoverlapping pointing’s withi ...
Galaxy Evolution Encyclopedia of Astronomy & Astrophysics eaa.iop.org Mauro Giavalisco
... has been shown that such ideas were incorrect, nonetheless the nomenclature has remained, and today it is common, for example, to refer to ellipticals and lenticulars as ‘earlytype galaxies’. The luminosity function One very powerful tool that describes in a quantitative way two of the most importan ...
... has been shown that such ideas were incorrect, nonetheless the nomenclature has remained, and today it is common, for example, to refer to ellipticals and lenticulars as ‘earlytype galaxies’. The luminosity function One very powerful tool that describes in a quantitative way two of the most importan ...
Detection of Earth-impacting asteroids with the next generation all
... changes have serious consequences for the survival and evolution of life on the planet. But in the past ∼50 years more than 170 impact structures have been identified on the surface of the Earth (Earth-impact database 2008). Were it not for the Earth’s protective atmosphere, oceans, erosion and plat ...
... changes have serious consequences for the survival and evolution of life on the planet. But in the past ∼50 years more than 170 impact structures have been identified on the surface of the Earth (Earth-impact database 2008). Were it not for the Earth’s protective atmosphere, oceans, erosion and plat ...
Malmquist bias
The Malmquist bias is an effect in observational astronomy which leads to the preferential detection of intrinsically bright objects. It was first described in 1922 by Swedish astronomer Gunnar Malmquist (1893–1982), who then greatly elaborated upon this work in 1925. In statistics, this bias is referred to as a selection bias and affects the survey results in a brightness limited survey, where stars below a certain apparent brightness are not included. Since observed stars and galaxies appear dimmer when farther away, the brightness that is measured will fall off with distance until their brightness falls below the observational threshold. Objects which are more luminous, or intrinsically brighter, can be observed at a greater distance, creating a false trend of increasing intrinsic brightness, and other related quantities, with distance. This effect has led to many spurious claims in the field of astronomy. Properly correcting for these effects has become an area of great focus.