Extragalactic Distances from Planetary Nebulae
... Elliptical galaxies do not have many (any?) 2 M main sequence stars. But they do have large numbers of 1 M stars. If some are in close binary systems which coalesce on the main sequence, the product may evolve into an [O III]-bright planetary. The ratio of bright planetaries to blue stragglers is ...
... Elliptical galaxies do not have many (any?) 2 M main sequence stars. But they do have large numbers of 1 M stars. If some are in close binary systems which coalesce on the main sequence, the product may evolve into an [O III]-bright planetary. The ratio of bright planetaries to blue stragglers is ...
Lecture 9: The interstellar medium (ISM)
... ammonia NH3 water H2O formaldehyde H2CO carbon monoxide CO ...
... ammonia NH3 water H2O formaldehyde H2CO carbon monoxide CO ...
Galaxies
... Galaxy mass measurements show that galaxies need between 3 and 10 times more mass than can be observed to explain their rotation curves. The discrepancy is even larger in galaxy clusters, which need 10 to 100 times more mass. The total needed is more than the sum of the dark matter associated with e ...
... Galaxy mass measurements show that galaxies need between 3 and 10 times more mass than can be observed to explain their rotation curves. The discrepancy is even larger in galaxy clusters, which need 10 to 100 times more mass. The total needed is more than the sum of the dark matter associated with e ...
Distance to VY Canis Majoris with VERA
... of J07252640 was determined with an accuracy of 0.34 mas in right ascension and 0.94 mas in declination, respectively (Kovalev et al. 2007). Because these offsets are constant at all epochs, it dose not affect the parallax measurements. Also, when the reference source is not a point source, the pos ...
... of J07252640 was determined with an accuracy of 0.34 mas in right ascension and 0.94 mas in declination, respectively (Kovalev et al. 2007). Because these offsets are constant at all epochs, it dose not affect the parallax measurements. Also, when the reference source is not a point source, the pos ...
Dust and molecular gas in the most distant quasars
... • We are seeing the end of the active bulge building in these strong mm quasars ? – The stellar bulge with a mass of a few 1011 to 1012 Msun already exist. • Require measurements of the bulge dynamical mass. • Resolve the stellar bulge at near-IR wavelengths. ...
... • We are seeing the end of the active bulge building in these strong mm quasars ? – The stellar bulge with a mass of a few 1011 to 1012 Msun already exist. • Require measurements of the bulge dynamical mass. • Resolve the stellar bulge at near-IR wavelengths. ...
Galaxies
... • Astronomers now have decided that the morphology classification should consist of only two types of galaxies: the spiral and the elliptical. • Barred spirals are a subclass of spirals. Irregulars may be either spiral or barred spiral. ...
... • Astronomers now have decided that the morphology classification should consist of only two types of galaxies: the spiral and the elliptical. • Barred spirals are a subclass of spirals. Irregulars may be either spiral or barred spiral. ...
The Submillimeter Frontier: A Space Science Imperative
... • z ∼ 1000 – The decoupling of radiation from matter allows baryonic matter to cluster around the dark matter. The universe becomes transparent, leaving behind the microwave background radiation observed by COBE. We know the statistics of the density field at this time, and believe that a linear the ...
... • z ∼ 1000 – The decoupling of radiation from matter allows baryonic matter to cluster around the dark matter. The universe becomes transparent, leaving behind the microwave background radiation observed by COBE. We know the statistics of the density field at this time, and believe that a linear the ...
AGN surveys to study galaxy evolution along cosmic times
... measuring the AGN and starburst contributions to their bolometric luminosities over a wide range of cosmological epochs, through their spectroscopic signatures. SPICA (Nakagawa et al. 2011) will be the next-generation, space infrared observatory, which, for the first time, will contain a large (3.2-m ...
... measuring the AGN and starburst contributions to their bolometric luminosities over a wide range of cosmological epochs, through their spectroscopic signatures. SPICA (Nakagawa et al. 2011) will be the next-generation, space infrared observatory, which, for the first time, will contain a large (3.2-m ...
Curriculum Vitae - Centre for Astrophysics and Supercomputing
... Research Interests • Modelling spectral energy distributions of galaxies • Stellar population synthesis models • Statistical interpretation of spectroscopic and photometric galaxy surveys • The formation and evolution of galaxies, comparison between theory/models and observations • The connections b ...
... Research Interests • Modelling spectral energy distributions of galaxies • Stellar population synthesis models • Statistical interpretation of spectroscopic and photometric galaxy surveys • The formation and evolution of galaxies, comparison between theory/models and observations • The connections b ...
Quiz 2 Lecture 12
... Which of the following statements is FALSE? a. Ring galaxies can be produced by head-on collisions between galaxies. b. The ratio of the number of elliptical to spiral galaxies remains constant over time. c. The Magellanic Clouds may eventually be "cannibalized" by our Galaxy. d. The shape of a gala ...
... Which of the following statements is FALSE? a. Ring galaxies can be produced by head-on collisions between galaxies. b. The ratio of the number of elliptical to spiral galaxies remains constant over time. c. The Magellanic Clouds may eventually be "cannibalized" by our Galaxy. d. The shape of a gala ...
Document
... mass density of the universe has roughly doubled since z ~ 1…Intriguingly, the integrated stellar mass of blue galaxies with young stars has not significantly changed since z ~ 1…instead, the growth of the total stellar mass density is dominated by the growth of the total mass in the largely passive ...
... mass density of the universe has roughly doubled since z ~ 1…Intriguingly, the integrated stellar mass of blue galaxies with young stars has not significantly changed since z ~ 1…instead, the growth of the total stellar mass density is dominated by the growth of the total mass in the largely passive ...
Radio Emission Toward Regions of Massive Star Formation
... Therefore, there must be some other important physics simple models do not take into account. The review by Zinnecker & Yorke (2007) discusses three prevailing theories: monolithic collapse in cores with masses much greater than the Jeans mass, competitive accretion by many stars in a dense protoclu ...
... Therefore, there must be some other important physics simple models do not take into account. The review by Zinnecker & Yorke (2007) discusses three prevailing theories: monolithic collapse in cores with masses much greater than the Jeans mass, competitive accretion by many stars in a dense protoclu ...
The local spiral structure of the Milky Way
... some spiral arm segments in the solar neighborhood were clearly identified (2, 3). Since then, many models have been proposed (4) and debated (5). Popular models (6, 7) suggest a grand design morphology with two- or four-armed spiral structure (8), such as M 51 or NGC 1232 (Fig. 1). Still, today, th ...
... some spiral arm segments in the solar neighborhood were clearly identified (2, 3). Since then, many models have been proposed (4) and debated (5). Popular models (6, 7) suggest a grand design morphology with two- or four-armed spiral structure (8), such as M 51 or NGC 1232 (Fig. 1). Still, today, th ...
Word
... 5. Limitations of the model There are several limitations of our computer model. First, it is only a two-dimensional demonstration of the galactic collision, but actually, the stars in the galaxies do not completely lie on the same plane. As a result, the model does not consider the 3-D component of ...
... 5. Limitations of the model There are several limitations of our computer model. First, it is only a two-dimensional demonstration of the galactic collision, but actually, the stars in the galaxies do not completely lie on the same plane. As a result, the model does not consider the 3-D component of ...
Galaxies
... 5. Limitations of the model There are several limitations of our computer model. First, it is only a two-dimensional demonstration of the galactic collision, but actually, the stars in the galaxies do not completely lie on the same plane. As a result, the model does not consider the 3-D component of ...
... 5. Limitations of the model There are several limitations of our computer model. First, it is only a two-dimensional demonstration of the galactic collision, but actually, the stars in the galaxies do not completely lie on the same plane. As a result, the model does not consider the 3-D component of ...
PH607lec12
... producing metals (elements other than hydrogen and helium) through the process of fusion. These metals were spewed into the galactic medium through stellar winds and supernova explosions and became part of the disc. This means that the stars in the disc formed out of metal rich material. This proces ...
... producing metals (elements other than hydrogen and helium) through the process of fusion. These metals were spewed into the galactic medium through stellar winds and supernova explosions and became part of the disc. This means that the stars in the disc formed out of metal rich material. This proces ...
2 Galaxy morphology and classification
... • Irr-II are peculiar systems, such as M82 (Figure 2.9). The amorphous appearance of M82 is due to a dust-enshrouded burst of star formation thought to have been triggered by a close encounter with M81. ...
... • Irr-II are peculiar systems, such as M82 (Figure 2.9). The amorphous appearance of M82 is due to a dust-enshrouded burst of star formation thought to have been triggered by a close encounter with M81. ...
The Classification of Galaxies By Daniel Underwood Contents The
... which helped identify them. But it didn’t end there... Even though galaxies these days are widely recognised, even by the average man on the street, their characteristics are not always consistent. It was pointed out by certain astronomers (namely Wolf, Hubble) that the structure of galaxies could b ...
... which helped identify them. But it didn’t end there... Even though galaxies these days are widely recognised, even by the average man on the street, their characteristics are not always consistent. It was pointed out by certain astronomers (namely Wolf, Hubble) that the structure of galaxies could b ...
Astro 6590: Galaxies and the Universe Astro
... Definition: what is a galaxy? • A galaxy is a self-gravitating collection of about 106 to 1011 stars, plus an amount up to 1/2 of as much by mass of gas, and about 10X as much by mass of dark matter. The stars and gas are about 70% hydrogen by mass and 25% helium, the rest being heavier elements (ca ...
... Definition: what is a galaxy? • A galaxy is a self-gravitating collection of about 106 to 1011 stars, plus an amount up to 1/2 of as much by mass of gas, and about 10X as much by mass of dark matter. The stars and gas are about 70% hydrogen by mass and 25% helium, the rest being heavier elements (ca ...
PPT - ALFALFA survey
... velocity moves outwards. Clusters, filaments and voids can be seen. To first order, the ADBS galaxies follow the spatial distribution of the UZC galaxies. This is to no surprise since ~50% of the ADBS galaxies are in the UZC. ...
... velocity moves outwards. Clusters, filaments and voids can be seen. To first order, the ADBS galaxies follow the spatial distribution of the UZC galaxies. This is to no surprise since ~50% of the ADBS galaxies are in the UZC. ...
Active Galactic Nuclei
... from stars, nebulae, and some galaxies. • There were also point-like, or star-like, radio sources which varied rapidly these are the `quasi-stellar’ radio sources or quasars. • In visible light quasars appear as points, like ...
... from stars, nebulae, and some galaxies. • There were also point-like, or star-like, radio sources which varied rapidly these are the `quasi-stellar’ radio sources or quasars. • In visible light quasars appear as points, like ...
Megamaser
A megamaser is a type of astrophysical maser, which is a naturally occurring source of stimulated spectral line emission. Megamasers are distinguished from astrophysical masers by their large isotropic luminosity. Megamasers have typical luminosities of 103 solar luminosities (L☉), which is 100 million times brighter than masers in the Milky Way, hence the prefix mega. Likewise, the term kilomaser is used to describe masers outside the Milky Way that have luminosities of order L☉, or thousands of times stronger than the average maser in the Milky Way, gigamaser is used to describe masers billions of times stronger than the average maser in the Milky Way, and extragalactic maser encompasses all masers found outside the Milky Way. Most known extragalactic masers are megamasers, and the majority of megamasers are hydroxyl (OH) megamasers, meaning the spectral line being amplified is one due to a transition in the hydroxyl molecule. There are known megamasers for three other molecules: water (H2O), formaldehyde (H2CO), and methine (CH).Water megamasers were the first type of megamaser discovered. The first water megamaser was found in 1979 in NGC 4945, a galaxy in the nearby Centaurus A/M83 Group. The first hydroxyl megamaser was found in 1982 in Arp 220, which is the nearest ultraluminous infrared galaxy to the Milky Way. All subsequent OH megamasers that have been discovered are also in luminous infrared galaxies, and there are a small number of OH kilomasers hosted in galaxies with lower infrared luminosities. Most luminous infrared galaxies have recently merged or interacted with another galaxy, and are undergoing a burst of star formation. Many of the characteristics of the emission in hydroxyl megamasers are distinct from that of hydroxyl masers within the Milky Way, including the amplification of background radiation and the ratio of hydroxyl lines at different frequencies. The population inversion in hydroxyl molecules is produced by far infrared radiation that results from absorption and re-emission of light from forming stars by surrounding interstellar dust. Zeeman splitting of hydroxyl megamaser lines may be used to measure magnetic fields in the masing regions, and this application represents the first detection of Zeeman splitting in a galaxy other than the Milky Way.Water megamasers and kilomasers are found primarily associated with active galactic nuclei, while galactic and weaker extragalactic water masers are found in star forming regions. Despite different environments, the circumstances that produce extragalactic water masers do not seem to be very different from those that produce galactic water masers. Observations of water megamasers have been used to make accurate measurements of distances to galaxies in order to provide constraints on the Hubble constant.