AST1100 Lecture Notes
... to this in later lectures). In the same figure (upper plot) you see the HRdiagram taken from a cluster with a known distance (measured by parallax). Since the distance is known, the apparent magnitudes could be converted to absolute magnitudes and for this reason we plot absolute magnitude on the y- ...
... to this in later lectures). In the same figure (upper plot) you see the HRdiagram taken from a cluster with a known distance (measured by parallax). Since the distance is known, the apparent magnitudes could be converted to absolute magnitudes and for this reason we plot absolute magnitude on the y- ...
document
... • Years ago in ancient Egypt, archaeologists unearthed the tomb of the Apis-bulls and couldn’t believe what they had found. Leading to the tomb was a paved avenue lined by lions that were carved out of stone. To enter the tomb they had to walk through a long and high arched narrow passageway cut int ...
... • Years ago in ancient Egypt, archaeologists unearthed the tomb of the Apis-bulls and couldn’t believe what they had found. Leading to the tomb was a paved avenue lined by lions that were carved out of stone. To enter the tomb they had to walk through a long and high arched narrow passageway cut int ...
Static, Infinite, Etern and Auto sustentable Universe
... decreases with a tendency to a distribution following the inverse square law. Maybe the Universe has a kind of fractal structure that follows a power law (although with variance of scale). We propose this class of distribution, because with this model, to certain scale, the matter reaches the homoge ...
... decreases with a tendency to a distribution following the inverse square law. Maybe the Universe has a kind of fractal structure that follows a power law (although with variance of scale). We propose this class of distribution, because with this model, to certain scale, the matter reaches the homoge ...
Downloadable Full Text
... The UFD Reticulum II (Ret II) was recently discovered with Dark Energy Survey data12,13 and confirmed to be one of the most metal-poor galaxies known14. On 1-4 Oct 2015, we obtained high-resolution spectra of the nine brightest member stars in Ret II (see Table 1, Extended Data Figure 1). The abunda ...
... The UFD Reticulum II (Ret II) was recently discovered with Dark Energy Survey data12,13 and confirmed to be one of the most metal-poor galaxies known14. On 1-4 Oct 2015, we obtained high-resolution spectra of the nine brightest member stars in Ret II (see Table 1, Extended Data Figure 1). The abunda ...
3D Tour of the Universe Template
... light in the band of the Milky Way as seen from Earth. They are actually small galaxies that have their own star formation, globular clusters, and the famous supernova of 1987 (in the LMC). These two galaxies are likely in the process of colliding with our Milky Way. Because our Milky Way is far mor ...
... light in the band of the Milky Way as seen from Earth. They are actually small galaxies that have their own star formation, globular clusters, and the famous supernova of 1987 (in the LMC). These two galaxies are likely in the process of colliding with our Milky Way. Because our Milky Way is far mor ...
G030338-00 - DCC
... » Analysis of data by many groups in LIGO Science Collaboration » Coincident running of multiple detectors across the globe » International team designing and building Advanced LIGO LIGO-G030338-00-R ...
... » Analysis of data by many groups in LIGO Science Collaboration » Coincident running of multiple detectors across the globe » International team designing and building Advanced LIGO LIGO-G030338-00-R ...
Calculating Parallax Lab
... 12. Parallax is only one method (known as “standard candles”) to determine the distance to nearby stars. There are several other methods that are used by astronomers. These methods each have their own specific technique and purpose, with some overlap to help confirm accuracy of other methods. Look a ...
... 12. Parallax is only one method (known as “standard candles”) to determine the distance to nearby stars. There are several other methods that are used by astronomers. These methods each have their own specific technique and purpose, with some overlap to help confirm accuracy of other methods. Look a ...
AST1100 Lecture Notes
... You will encounter the Hertzsprung-Russell (HR) diagram on several occations during this course. Here you will only get a short introduction and just enough information in order to be able to use it for the estimation of distances. In the lectures on stellar evolution, you will get more details. The ...
... You will encounter the Hertzsprung-Russell (HR) diagram on several occations during this course. Here you will only get a short introduction and just enough information in order to be able to use it for the estimation of distances. In the lectures on stellar evolution, you will get more details. The ...
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 ...
The Interstellar Medium White Paper
... From a theoretical perspective, although the picture is becoming steadily clearer, there are many aspects of the dynamics of the Galactic nucleus and its outflow that we do not understand. It is still under debate, for instance, whether it has indeed been star formation (Crocker and Aharonian 2011) ...
... From a theoretical perspective, although the picture is becoming steadily clearer, there are many aspects of the dynamics of the Galactic nucleus and its outflow that we do not understand. It is still under debate, for instance, whether it has indeed been star formation (Crocker and Aharonian 2011) ...
M81/M82/NGC3077
... The two galaxies have indeed passed each other not long ago. The line-of-sight separation is 0.27 Mpc. Calculated using the velocity difference gives a time scale of approximately 1x109 years, consistent with the enhanced star ...
... The two galaxies have indeed passed each other not long ago. The line-of-sight separation is 0.27 Mpc. Calculated using the velocity difference gives a time scale of approximately 1x109 years, consistent with the enhanced star ...
Star formation and internal kinematics of irregular galaxies
... of parsecs and a couple of kiloparsecs. Thus a galaxy’s global structure and dynamics can be viewed as an organising framework, collecting up neutral gas and perhaps providing a trigger, after which a series of events leading to nuclear ignition proceeds under the control of forces largely independe ...
... of parsecs and a couple of kiloparsecs. Thus a galaxy’s global structure and dynamics can be viewed as an organising framework, collecting up neutral gas and perhaps providing a trigger, after which a series of events leading to nuclear ignition proceeds under the control of forces largely independe ...
Stars, Galaxies, and the Universe Section 1
... Magellanic Cloud, are our closest neighbors. • Within 5 million light-years of the Milky Way are about 30 other galaxies. These galaxies and the Milky Way galaxy are collectively called the Local Group. ...
... Magellanic Cloud, are our closest neighbors. • Within 5 million light-years of the Milky Way are about 30 other galaxies. These galaxies and the Milky Way galaxy are collectively called the Local Group. ...
THE SHAPES OF ATOMIC LINES FROM THE SURFACES OF
... At a given instant, the X-ray-emitting portion of the neutron star surface could be a hot spot (produced, e.g., by magnetically channeled accretion, confined thermonuclear burning, or localized cooling gas), a belt (produced, e.g., by disk accretion near the rotational equator or rotationally confin ...
... At a given instant, the X-ray-emitting portion of the neutron star surface could be a hot spot (produced, e.g., by magnetically channeled accretion, confined thermonuclear burning, or localized cooling gas), a belt (produced, e.g., by disk accretion near the rotational equator or rotationally confin ...
21_Testbank
... 1) Give examples demonstrating the role of "nature" and "nurture" in galaxy evolution. Answer: Galaxies come in a wide variety of shapes and sizes. Protogalactic clouds that had low angular momentum may have formed spheroidal stellar systems (elliptical galaxies), while clouds with higher angular mo ...
... 1) Give examples demonstrating the role of "nature" and "nurture" in galaxy evolution. Answer: Galaxies come in a wide variety of shapes and sizes. Protogalactic clouds that had low angular momentum may have formed spheroidal stellar systems (elliptical galaxies), while clouds with higher angular mo ...
Brown et al. 2008 Studying Resolved Stellar
... sightlines through galaxies beyond the local group. Observations of red-giant branch (RGB) stars are much easier and can potentially be carried out for hundreds of galaxies out to distances beyond the Virgo Cluster. For old stellar populations, the RGB is a good metallicity indicator. Hence systemat ...
... sightlines through galaxies beyond the local group. Observations of red-giant branch (RGB) stars are much easier and can potentially be carried out for hundreds of galaxies out to distances beyond the Virgo Cluster. For old stellar populations, the RGB is a good metallicity indicator. Hence systemat ...
PDF format
... True or False? If you want to find elliptical galaxies, you'll have better luck looking in clusters of galaxies than elsewhere in the universe. a) True, galaxy clusters have a much higher percentage of elliptical galaxies than do other parts of the universe. b) True, elliptical galaxies are found ...
... True or False? If you want to find elliptical galaxies, you'll have better luck looking in clusters of galaxies than elsewhere in the universe. a) True, galaxy clusters have a much higher percentage of elliptical galaxies than do other parts of the universe. b) True, elliptical galaxies are found ...
Black Holes - Gresham College
... believed to result from the collapse of a giant star of perhaps 20 solar masses whose stellar core has a mass exceeding ~ 3 solar masses. This is the point at which we believe that neutron degeneracy pressure (which allows stellar cores in the range 1.4 to 3 solar masses to form neutron stars) can n ...
... believed to result from the collapse of a giant star of perhaps 20 solar masses whose stellar core has a mass exceeding ~ 3 solar masses. This is the point at which we believe that neutron degeneracy pressure (which allows stellar cores in the range 1.4 to 3 solar masses to form neutron stars) can n ...
Curriculum Vitae - Centre for Astrophysics and Supercomputing
... Total: 61 publications (of which 5 first-author) with a total of 1562 citations; h-index of 22; m-index of 3.1 (statistics from ADS). 1. Pacifici, Camilla, da Cunha, Elisabete, Charlot, Stéphane et al., On the importance of using appropriate spectral models to derive physical properties of galaxies ...
... Total: 61 publications (of which 5 first-author) with a total of 1562 citations; h-index of 22; m-index of 3.1 (statistics from ADS). 1. Pacifici, Camilla, da Cunha, Elisabete, Charlot, Stéphane et al., On the importance of using appropriate spectral models to derive physical properties of galaxies ...
Evolution and nucleosynthesis of extremely metal
... Context. Models of primordial and hyper-metal-poor stars that have masses similar to the Sun are known to experience an ingestion of protons into the hot core during the core helium flash phase at the end of their red giant branch evolution. This produces a concurrent secondary flash powered by hydr ...
... Context. Models of primordial and hyper-metal-poor stars that have masses similar to the Sun are known to experience an ingestion of protons into the hot core during the core helium flash phase at the end of their red giant branch evolution. This produces a concurrent secondary flash powered by hydr ...
Neutron star masses: dwarfs, giants and neighbors
... We consider the possible existence of a common channel of evolution of binary systems, which results in a GRB during the formation of a BH or the birth of a magnetar during the formation of a NS. We assume that the rapid rotation of the core of a collapsing star can be explained by tidal synchroniza ...
... We consider the possible existence of a common channel of evolution of binary systems, which results in a GRB during the formation of a BH or the birth of a magnetar during the formation of a NS. We assume that the rapid rotation of the core of a collapsing star can be explained by tidal synchroniza ...
The Milky Way - The Independent School
... From the measurement of stellar velocities near the center of a galaxy: Infer mass in the very center central black holes! Several million, up to more than a billion solar masses! Supermassive ...
... From the measurement of stellar velocities near the center of a galaxy: Infer mass in the very center central black holes! Several million, up to more than a billion solar masses! Supermassive ...
J: Chapter 4: Stars and Galaxies
... Parallax can be seen if you observe the same star when Earth is at two different points during its orbit around the Sun. The star’s position relative to more distant background stars will appear to change. Is star or farther from Earth? ...
... Parallax can be seen if you observe the same star when Earth is at two different points during its orbit around the Sun. The star’s position relative to more distant background stars will appear to change. Is star or farther from Earth? ...
Gamma-ray burst
Gamma-ray bursts (GRBs) are flashes of gamma rays associated with extremely energetic explosions that have been observed in distant galaxies. They are the brightest electromagnetic events known to occur in the universe. Bursts can last from ten milliseconds to several hours. The initial burst is usually followed by a longer-lived ""afterglow"" emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, microwave and radio).Most observed GRBs are believed to consist of a narrow beam of intense radiation released during a supernova or hypernova as a rapidly rotating, high-mass star collapses to form a neutron star, quark star, or black hole. A subclass of GRBs (the ""short"" bursts) appear to originate from a different process – this may be due to the merger of binary neutron stars. The cause of the precursor burst observed in some of these short events may be due to the development of a resonance between the crust and core of such stars as a result of the massive tidal forces experienced in the seconds leading up to their collision, causing the entire crust of the star to shatter.The sources of most GRBs are billions of light years away from Earth, implying that the explosions are both extremely energetic (a typical burst releases as much energy in a few seconds as the Sun will in its entire 10-billion-year lifetime) and extremely rare (a few per galaxy per million years). All observed GRBs have originated from outside the Milky Way galaxy, although a related class of phenomena, soft gamma repeater flares, are associated with magnetars within the Milky Way. It has been hypothesized that a gamma-ray burst in the Milky Way, pointing directly towards the Earth, could cause a mass extinction event.GRBs were first detected in 1967 by the Vela satellites, a series of satellites designed to detect covert nuclear weapons tests. Hundreds of theoretical models were proposed to explain these bursts in the years following their discovery, such as collisions between comets and neutron stars. Little information was available to verify these models until the 1997 detection of the first X-ray and optical afterglows and direct measurement of their redshifts using optical spectroscopy, and thus their distances and energy outputs. These discoveries, and subsequent studies of the galaxies and supernovae associated with the bursts, clarified the distance and luminosity of GRBs. These facts definitively placed them in distant galaxies and also connected long GRBs with the explosion of massive stars, the only possible source for the energy outputs observed.