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Astronomy Astrophysics − Astrophysical parameters of the peculiar X-ray transient
... of the radial velocity changes. Very significant variations, uncorrelated with those of the photospheric lines are seen in the shape and position of the Hα emission feature around the time of the X-ray outburst, but large excursions are also observed at other times. Conclusions. HD 306414 is a norma ...
... of the radial velocity changes. Very significant variations, uncorrelated with those of the photospheric lines are seen in the shape and position of the Hα emission feature around the time of the X-ray outburst, but large excursions are also observed at other times. Conclusions. HD 306414 is a norma ...
The Formation and Evolution of Massive Black Holes - Ira-Inaf
... MBHs become visible when they accrete gas directly from their surroundings, or, occasionally, when they disrupt an unlucky star passing too close by (20). The gravitational potential energy of the accreted mass is converted to radiation, making the black hole luminous. Luminous, accreting MBHs are g ...
... MBHs become visible when they accrete gas directly from their surroundings, or, occasionally, when they disrupt an unlucky star passing too close by (20). The gravitational potential energy of the accreted mass is converted to radiation, making the black hole luminous. Luminous, accreting MBHs are g ...
A comparison of the s- and r-process element evolution in local
... 2007, and references therein) and a few clues have emerged, but no definitive answers have given. The Local Group is an excellent laboratory for shedding some light on that matter, due to the possibility of studying the properties of different types of galaxy in details. This includes large disk gala ...
... 2007, and references therein) and a few clues have emerged, but no definitive answers have given. The Local Group is an excellent laboratory for shedding some light on that matter, due to the possibility of studying the properties of different types of galaxy in details. This includes large disk gala ...
Astrometry of Asteroids
... stars that are selected by astronomers for a particular purpose. One of the most important catalogs is called the FK5 Catalog, because it is one of the fundamental catalogs used as a reference for measuring the positions to other stars in the sky (see the next section of this manual). The FK5 Catalo ...
... stars that are selected by astronomers for a particular purpose. One of the most important catalogs is called the FK5 Catalog, because it is one of the fundamental catalogs used as a reference for measuring the positions to other stars in the sky (see the next section of this manual). The FK5 Catalo ...
Ch. 19 - Astro1010
... occurred in our part of the Milky Way since the invention of the telescope so we have not had the opportunity to study one up close. We have seen many in other galaxies as well as remnants in our galaxy. ...
... occurred in our part of the Milky Way since the invention of the telescope so we have not had the opportunity to study one up close. We have seen many in other galaxies as well as remnants in our galaxy. ...
On the Spiral Structure of the Milky Way Galaxy
... instability due to regular magnetic field directed along the arm. Observational indications for this assumption were recently found in the north-western fragment of the S4 spiral arm in the Andromeda galaxy, just the arm with regular wave-shaped magnetic field along it detected long ago [see 7, 8]. ...
... instability due to regular magnetic field directed along the arm. Observational indications for this assumption were recently found in the north-western fragment of the S4 spiral arm in the Andromeda galaxy, just the arm with regular wave-shaped magnetic field along it detected long ago [see 7, 8]. ...
STRUCTURAL CHARACTERISTICS AND STELLAR
... 1991). The area weighted colors are less aected and should be more representative of the underlying stellar population. Indeed, this is a much greater concern for broad band colors of HSB disks, where the star formation rate and H II region covering factor are higher. Due to bad weather, some galax ...
... 1991). The area weighted colors are less aected and should be more representative of the underlying stellar population. Indeed, this is a much greater concern for broad band colors of HSB disks, where the star formation rate and H II region covering factor are higher. Due to bad weather, some galax ...
Minimum Distance Estimation of Milky Way
... and velocities, live in a circular patch in the neighborhood of the Sun in the 2-dimensional Milky Way disk; thus, the center of this circular patch is at the location of the Sun and the radius of this patch is small () compared to kXk, where k · k is the Euclidean norm of a vector. It is noted tha ...
... and velocities, live in a circular patch in the neighborhood of the Sun in the 2-dimensional Milky Way disk; thus, the center of this circular patch is at the location of the Sun and the radius of this patch is small () compared to kXk, where k · k is the Euclidean norm of a vector. It is noted tha ...
The Interstellar Medium in High Redshift Galaxies Comes of Age
... in the COSMOS field at z∼1.5, separated by ∼80 Mpc. The galaxies are luminous ULIRGs and are well-detected at all bands from the optical through the radio. However, the radio-bright galaxy has significantly weaker CO emission than its neighbor suggesting differing AGN activity at their cores. We dis ...
... in the COSMOS field at z∼1.5, separated by ∼80 Mpc. The galaxies are luminous ULIRGs and are well-detected at all bands from the optical through the radio. However, the radio-bright galaxy has significantly weaker CO emission than its neighbor suggesting differing AGN activity at their cores. We dis ...
PDF - Department of Statistics
... the arithmetic mean and standard deviation in order to guard against occultations and aberrant outliers. Let Yksh denote the resulting test statistic for hold h of star s on telescope k. We now describe a test based on measurements at multiple telescopes which flags a star-hold if Yksh is sufficient ...
... the arithmetic mean and standard deviation in order to guard against occultations and aberrant outliers. Let Yksh denote the resulting test statistic for hold h of star s on telescope k. We now describe a test based on measurements at multiple telescopes which flags a star-hold if Yksh is sufficient ...
Collisions and Encounters of Stellar Systems
... the galaxies are uncorrelated, the rate at which an L! galaxy suffers collisions with similar galaxies is then expected to be of order nΣvp ≈ 10−6 Gyr−1 , so only about one galaxy in 105 would suffer a collision during the age of the universe. Such arguments led astronomers to think of galaxies as i ...
... the galaxies are uncorrelated, the rate at which an L! galaxy suffers collisions with similar galaxies is then expected to be of order nΣvp ≈ 10−6 Gyr−1 , so only about one galaxy in 105 would suffer a collision during the age of the universe. Such arguments led astronomers to think of galaxies as i ...
Evidence for strong evolution in galaxy environmental quenching
... way to the cluster catalogues. We used EAZY (Brammer et al. 2008) to obtain photometric redshifts and the restframe U − V and V − J colours needed to estimate passive and star-forming fractions (Wuyts et al. 2007). We use the Whitaker et al. (2011) U V J criterion, as in vdB+13. We used FAST (Kriek ...
... way to the cluster catalogues. We used EAZY (Brammer et al. 2008) to obtain photometric redshifts and the restframe U − V and V − J colours needed to estimate passive and star-forming fractions (Wuyts et al. 2007). We use the Whitaker et al. (2011) U V J criterion, as in vdB+13. We used FAST (Kriek ...
THE MORPHOLOGICAL DEMOGRAPHICS OF GALAXIES IN THE
... has been modified from earlier BPZ versions to remove differences between the predicted colors and those of real galaxies, which results in improved BPZ estimates (see Benítez et al. 2004, for details). We note that Coe et al. (2005) have followed a similar approach to estimate the UV-SFR using also ...
... has been modified from earlier BPZ versions to remove differences between the predicted colors and those of real galaxies, which results in improved BPZ estimates (see Benítez et al. 2004, for details). We note that Coe et al. (2005) have followed a similar approach to estimate the UV-SFR using also ...
Dynamical Interactions Make Hot Jupiters in Open Star Clusters
... In all standard simulations the outer Jupiters commonly migrate inwards to as close as a = 7.5 AU and outwards to as far as a = 12 AU. The former value means that outer Jupiters reach close to the dynamical stability limit for inner Jupiters that have not migrated. Some of the inner Jupiters migrate ...
... In all standard simulations the outer Jupiters commonly migrate inwards to as close as a = 7.5 AU and outwards to as far as a = 12 AU. The former value means that outer Jupiters reach close to the dynamical stability limit for inner Jupiters that have not migrated. Some of the inner Jupiters migrate ...
Evolution of the Mass-to-light Ratio of Galaxies to z~0.25
... We obtained HI profiles of adequate quality for velocity width measurements for 20 galaxies with 0.17 ≤ z ≤ 0.25, 12 of which have been fully processed. Total average integration times (half spent on-source) ranged between 2 and 6 hours, making these observations for a significant number of object ...
... We obtained HI profiles of adequate quality for velocity width measurements for 20 galaxies with 0.17 ≤ z ≤ 0.25, 12 of which have been fully processed. Total average integration times (half spent on-source) ranged between 2 and 6 hours, making these observations for a significant number of object ...
Early Star-Forming Galaxies and the Reionisation of the Universe
... new Hubble data has now indicated that this trend continues to higher redshift where UV slopes with β < -2.5 have been claimed42,44. As the youngest starburst galaxies in the local Universe show UV spectra with β > -2.558,59, and extreme slopes (β < -3) may indicate Population III stars60,61, the s ...
... new Hubble data has now indicated that this trend continues to higher redshift where UV slopes with β < -2.5 have been claimed42,44. As the youngest starburst galaxies in the local Universe show UV spectra with β > -2.558,59, and extreme slopes (β < -3) may indicate Population III stars60,61, the s ...
Next Generation VLA Science White Paper
... The last decades have seen enormous advances in our knowledge of interstellar medium structure in the Milky Way and other galaxies, and with it a better understanding of how stars are born and galaxies grow and die. However, these have come largely from bulk tracers of interstellar gas — tools like ...
... The last decades have seen enormous advances in our knowledge of interstellar medium structure in the Milky Way and other galaxies, and with it a better understanding of how stars are born and galaxies grow and die. However, these have come largely from bulk tracers of interstellar gas — tools like ...
1. Estimate the average mass density of a sodium atom assuming its
... stars. The baseline AB is the line joining the Earth’s two locations six months apart in its orbit around the Sun. That is, the baseline is about the diameter of the Earth’s orbit ∼ 3 ×1011m. However, even the nearest stars are so distant that with such a long baseline they show parallax only of the ...
... stars. The baseline AB is the line joining the Earth’s two locations six months apart in its orbit around the Sun. That is, the baseline is about the diameter of the Earth’s orbit ∼ 3 ×1011m. However, even the nearest stars are so distant that with such a long baseline they show parallax only of the ...
THE RED-SEQUENCE LUMINOSITY FUNCTION IN GALAXY
... The Red-Sequence Cluster Survey ( RCS-1; Gladders & Yee 2005) is a two-filter imaging survey covering 100 deg2. It was designed to build a well-defined sample of galaxy clusters out to z 1 using a highly efficient color selection technique (Gladders & Yee 2000, 2005). This technique provides a ph ...
... The Red-Sequence Cluster Survey ( RCS-1; Gladders & Yee 2005) is a two-filter imaging survey covering 100 deg2. It was designed to build a well-defined sample of galaxy clusters out to z 1 using a highly efficient color selection technique (Gladders & Yee 2000, 2005). This technique provides a ph ...
The Space Density of Spiral Galaxies as f(magnitude, size and
... observed trends between stellar ages & metallicities and galaxy surface brightness parameters ...
... observed trends between stellar ages & metallicities and galaxy surface brightness parameters ...
disappearance of comet c/2010 x1 (elenin): gone with a whimper
... (HI-1A). The longer median durations were used to obtain better rejection of background stars as the comet was projected against the Milky Way as seen from the latter spacecraft. Equivalent median images were calculated for standard stars in the same way as for the comet. Field stars for photometric ...
... (HI-1A). The longer median durations were used to obtain better rejection of background stars as the comet was projected against the Milky Way as seen from the latter spacecraft. Equivalent median images were calculated for standard stars in the same way as for the comet. Field stars for photometric ...
SN Ia host galaxy properties and the dust extinction
... probe the host galaxy dust disc characteristics, as large samples of SN in the nearby Universe, complete with host galaxy properties, are becoming available, notably the SDSS-SN search. In this paper, we compare the distribution of dust extinction values (AV ) for the SN in this sample (Frieman et a ...
... probe the host galaxy dust disc characteristics, as large samples of SN in the nearby Universe, complete with host galaxy properties, are becoming available, notably the SDSS-SN search. In this paper, we compare the distribution of dust extinction values (AV ) for the SN in this sample (Frieman et a ...
The Age Distribution of Potential Intelligent Life in the Milky Way
... From this equation we can see that the gas mass lost as it is turned into stars (per parsec squared per year) is proportional to the total mass of gas (per parsec squared) to the power n. Observations of distant galaxies have found this relationship to hold consistently, just with varying values of ...
... From this equation we can see that the gas mass lost as it is turned into stars (per parsec squared per year) is proportional to the total mass of gas (per parsec squared) to the power n. Observations of distant galaxies have found this relationship to hold consistently, just with varying values of ...
The binary fraction of the young cluster NGC 1818 in the Large
... of stars place important constraints on star formation and the origin of the stellar initial mass function (IMF; Goodwin et al. 2007, 2008). The majority of stars with masses greater than approximately 0.5M are also thought to form in star clusters (Lada & Lada 2003), and the binary content of a st ...
... of stars place important constraints on star formation and the origin of the stellar initial mass function (IMF; Goodwin et al. 2007, 2008). The majority of stars with masses greater than approximately 0.5M are also thought to form in star clusters (Lada & Lada 2003), and the binary content of a st ...
A search for nearby counterparts to the moving objects in the Hubble
... Ibata et al. have recently discovered very faint, moving objects in the Hubble Deep Field (HDF). The number, apparent magnitudes and proper motions of these objects are consistent with old white dwarfs making up part of the Galactic dark halo. We review a number of ground-based proper motion surveys ...
... Ibata et al. have recently discovered very faint, moving objects in the Hubble Deep Field (HDF). The number, apparent magnitudes and proper motions of these objects are consistent with old white dwarfs making up part of the Galactic dark halo. We review a number of ground-based proper motion surveys ...
Cosmic distance ladder
The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects. A real direct distance measurement of an astronomical object is possible only for those objects that are ""close enough"" (within about a thousand parsecs) to Earth. The techniques for determining distances to more distant objects are all based on various measured correlations between methods that work at close distances and methods that work at larger distances. Several methods rely on a standard candle, which is an astronomical object that has a known luminosity.The ladder analogy arises because no one technique can measure distances at all ranges encountered in astronomy. Instead, one method can be used to measure nearby distances, a second can be used to measure nearby to intermediate distances, and so on. Each rung of the ladder provides information that can be used to determine the distances at the next higher rung.