presentation source
... Quasars have been observed to fluctuate in brightness with periods ranging from a few years to a few hours. Recall that this light variation places an upper limit on the size of the quasar’s energy source. If they are as distant as Hubble’s Law indicates then some mechanism must be producing energie ...
... Quasars have been observed to fluctuate in brightness with periods ranging from a few years to a few hours. Recall that this light variation places an upper limit on the size of the quasar’s energy source. If they are as distant as Hubble’s Law indicates then some mechanism must be producing energie ...
sporadic solar radio emission at decameter wavelengths
... operating in decameter wavelengths band [Braude et al., 1978]. It was involved in solar observations since the beginning of the seventies of the previous century. Usually the observations were carried out using the filter bank spectrometers with only 6 or 8 channels. These limitations did not allow ...
... operating in decameter wavelengths band [Braude et al., 1978]. It was involved in solar observations since the beginning of the seventies of the previous century. Usually the observations were carried out using the filter bank spectrometers with only 6 or 8 channels. These limitations did not allow ...
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 stars. ...
... 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 stars. ...
Starbursts – from 30 Doradus to Lyman
... tarbursts are intense episodes of star formation in which the surface density of star formation ranges up to 10 000 times that in normal galaxies. They are important features of early galaxy evolution. Many of the distant, high-redshift galaxies we are able to detect are in a starbursting phase, oft ...
... tarbursts are intense episodes of star formation in which the surface density of star formation ranges up to 10 000 times that in normal galaxies. They are important features of early galaxy evolution. Many of the distant, high-redshift galaxies we are able to detect are in a starbursting phase, oft ...
Quasars: Back to the Infant Universe
... What observations of quasars tell us they are small? What are Seyferts and Radio Galaxies? What is at the center of a galaxy that powers a quasar? Why are there few quasars close to us? Could quasars ever have existed close to us? Why is gas important? What is the merger cycle that drives quasars? W ...
... What observations of quasars tell us they are small? What are Seyferts and Radio Galaxies? What is at the center of a galaxy that powers a quasar? Why are there few quasars close to us? Could quasars ever have existed close to us? Why is gas important? What is the merger cycle that drives quasars? W ...
Build your own Galaxy - McDonald Observatory
... oven cooks food by emitting strong radio waves, called microwaves, at a 12-centimeter wavelength). Astronomers have detected hydrogen far beyond the luminous stars of our galaxy. In your model, the hydrogen clouds would extend an additional nine centimeters from the edge of the disk. In real space, ...
... oven cooks food by emitting strong radio waves, called microwaves, at a 12-centimeter wavelength). Astronomers have detected hydrogen far beyond the luminous stars of our galaxy. In your model, the hydrogen clouds would extend an additional nine centimeters from the edge of the disk. In real space, ...
has occurred over the past 14 billion years COSMIC DOWNSIZING
... used SCUBA to directly image regions of the sky with sufficient sensitivity and area coverage to discover distant, exceptionally luminous dust-obscured sources. Because the resolution is fairly coarse, the galaxies have a bloblike appearance [see illustration above]. They are also relatively rare — ...
... used SCUBA to directly image regions of the sky with sufficient sensitivity and area coverage to discover distant, exceptionally luminous dust-obscured sources. Because the resolution is fairly coarse, the galaxies have a bloblike appearance [see illustration above]. They are also relatively rare — ...
The Hubble sequence, overview of galaxies
... • Period-luminosity relation discovered by Henrietta Swan Leavitt in early 20th century • If we measure the pulsation period, we then know the luminosity of the star and therefore can determine how far away it is (but the method must be calibrated with another distance indicator!) • One of the most ...
... • Period-luminosity relation discovered by Henrietta Swan Leavitt in early 20th century • If we measure the pulsation period, we then know the luminosity of the star and therefore can determine how far away it is (but the method must be calibrated with another distance indicator!) • One of the most ...
Power Point Presentation
... No repeatable periods seen in bursts No orbital periods seen – not in binaries Thousands of bursts seen to date – no repetitions from same location Isotropic distribution Afterglows have detectable redshifts which indicate GRBs are at cosmological distances (i.e., far outside our galaxy) Lg = 1052 - ...
... No repeatable periods seen in bursts No orbital periods seen – not in binaries Thousands of bursts seen to date – no repetitions from same location Isotropic distribution Afterglows have detectable redshifts which indicate GRBs are at cosmological distances (i.e., far outside our galaxy) Lg = 1052 - ...
1_Introduction
... First star to have its parallax angle measured: 61 Cygni (in the year 1838). Parallax angle = 0.287 arcseconds Distance = 1 parsec / 0.287 = 3.48 parsecs ...
... First star to have its parallax angle measured: 61 Cygni (in the year 1838). Parallax angle = 0.287 arcseconds Distance = 1 parsec / 0.287 = 3.48 parsecs ...
Galaxies - science9atsouthcarletonhs
... The LMC is about 60,000 light years across. The bright reddish feature in the upper right is the “Tarantula Nebula” a region of star formation in the LMC. (NOAO/AURA Photo) ...
... The LMC is about 60,000 light years across. The bright reddish feature in the upper right is the “Tarantula Nebula” a region of star formation in the LMC. (NOAO/AURA Photo) ...
11 Stellar Remnants - Journigan-wiki
... The Type I Supernova The nova process can repeat itself over and over again given that the dwarf does not accumulate too much material. If enough gas gathers to push the dwarf over the Chandrasekhar Limit, the star will collapse unto a Type I supernova. This rapid collapse will eventually cause the ...
... The Type I Supernova The nova process can repeat itself over and over again given that the dwarf does not accumulate too much material. If enough gas gathers to push the dwarf over the Chandrasekhar Limit, the star will collapse unto a Type I supernova. This rapid collapse will eventually cause the ...
Early Spring Observing – Millstone News Night Sky
... The Beehive contains a larger star population than most other nearby clusters. Under dark skies the Beehive Cluster looks like a nebulous object to the naked eye; thus it has been known since ancient times. We often find it, rather than the constellation it is found in (Cancer). From Wikipedia: The ...
... The Beehive contains a larger star population than most other nearby clusters. Under dark skies the Beehive Cluster looks like a nebulous object to the naked eye; thus it has been known since ancient times. We often find it, rather than the constellation it is found in (Cancer). From Wikipedia: The ...
Quasars
... this was a very distant object that was masquerading as a star, a quasi-stellar object. • They were first measured to be very small in angular size, but have immense power output. • It is now known that they are actually very ...
... this was a very distant object that was masquerading as a star, a quasi-stellar object. • They were first measured to be very small in angular size, but have immense power output. • It is now known that they are actually very ...
File
... • ages of stars are mainly old; most as old as the galaxy • very little to no gas; it has been converted to stars already • overall structure is smooth- no clumpy areas like analogous to spiral arms in disks ...
... • ages of stars are mainly old; most as old as the galaxy • very little to no gas; it has been converted to stars already • overall structure is smooth- no clumpy areas like analogous to spiral arms in disks ...
RXTE PCA Contributions to Monitoring Fast Transients
... Rapid Burster and GRS 1747-312: similar durations, different luminosities; XTE J1751-305 vs SAX J1808.4-3658: shorter, but higher luminosity. Many faint transients with distance estimates (from bursts or globular cluster membership) are just distant, not low luminosity at peak or low average dM/dt . ...
... Rapid Burster and GRS 1747-312: similar durations, different luminosities; XTE J1751-305 vs SAX J1808.4-3658: shorter, but higher luminosity. Many faint transients with distance estimates (from bursts or globular cluster membership) are just distant, not low luminosity at peak or low average dM/dt . ...
PROBLEM SET #9 SOLUTIONS AST142 1. Quasar luminosity
... is accreting at the Eddington rate, and show that these two findings are consistent with one another. ...
... is accreting at the Eddington rate, and show that these two findings are consistent with one another. ...
Stars
... The key to locating the North Star in the night sky is to first find the Big Dipper, a constellation of stars known as Ursa Major.. The Big Dipper is perhaps the best known group of stars in the northern sky and is easy to distinguish from all others. Also known as the Great Bear, the Big Dipper is ...
... The key to locating the North Star in the night sky is to first find the Big Dipper, a constellation of stars known as Ursa Major.. The Big Dipper is perhaps the best known group of stars in the northern sky and is easy to distinguish from all others. Also known as the Great Bear, the Big Dipper is ...
Mark Rubin
... • At least a fraction of Type IIn supernovae (SNe IIn) are energetic PISNe, providing the only observable examples of this process. They have potential to yield enormous insight into the behavior of high-mass (> 140 Msolar) Pop III stars. • Moreover, SNe IIn are the most luminous SN type in the rest ...
... • At least a fraction of Type IIn supernovae (SNe IIn) are energetic PISNe, providing the only observable examples of this process. They have potential to yield enormous insight into the behavior of high-mass (> 140 Msolar) Pop III stars. • Moreover, SNe IIn are the most luminous SN type in the rest ...
DTU 8e Chap 17 Quasars and Other Active Galaxies
... its core. Active galaxies include quasars, Seyfert galaxies, radio galaxies, double-radio sources, and BL Lacertae objects. A quasar, or quasi-stellar radio source, is an object that looks like a star but has a huge redshift. This redshift corresponds to a distance of billions of light-years from Ea ...
... its core. Active galaxies include quasars, Seyfert galaxies, radio galaxies, double-radio sources, and BL Lacertae objects. A quasar, or quasi-stellar radio source, is an object that looks like a star but has a huge redshift. This redshift corresponds to a distance of billions of light-years from Ea ...
![Collecting Area [km 2 ]](http://s1.studyres.com/store/data/005251749_1-ac6dff2cb85965aa98ca71572274094f-300x300.png)
Collecting Area [km 2 ]
... • In principle, collection area can be increased ad infinitum. The collection area of present ACTs is defined by the light pool size. The detector becomes larger than the light pool above ~105m2. Future ACT arrays head toward >1km2 ...
... • In principle, collection area can be increased ad infinitum. The collection area of present ACTs is defined by the light pool size. The detector becomes larger than the light pool above ~105m2. Future ACT arrays head toward >1km2 ...
Hubble - STScI
... Imagine a powerful burst of light and other radiation that can burn away the ozone in Earth’s atmosphere. Luckily, bursts of light that strong occur so far away they will not scorch our planet. These bursts of light are called gamma-ray bursts. They may represent the most powerful explosions in the ...
... Imagine a powerful burst of light and other radiation that can burn away the ozone in Earth’s atmosphere. Luckily, bursts of light that strong occur so far away they will not scorch our planet. These bursts of light are called gamma-ray bursts. They may represent the most powerful explosions in the ...
File
... The universe contains all of the matter and energy known by humans to exist. Some scientists have hypothesized that there may be parallel universes that we cannot detect, but there is no evidence to support their existence. The universe is known to contain billions of galaxies, though it is impossib ...
... The universe contains all of the matter and energy known by humans to exist. Some scientists have hypothesized that there may be parallel universes that we cannot detect, but there is no evidence to support their existence. The universe is known to contain billions of galaxies, though it is impossib ...
Basics of Astrophysics
... The speckle pattern change rapidly, if v is the speed of the wind the timescale can be roughly estimated by t = r/v where r is the size of the cell causing the speckle. With a rather ...
... The speckle pattern change rapidly, if v is the speed of the wind the timescale can be roughly estimated by t = r/v where r is the size of the cell causing the speckle. With a rather ...
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.