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... At the position of the GRB in the difference images, our photometric analysis gives R606,AB >28.25 (2 upper limit) and H160,AB = 25.73±0.20. In both cases, we fitted a model point-spread function (psf) and estimated the errors from the variance of the flux at a large number of locations chosen to ha ...
... At the position of the GRB in the difference images, our photometric analysis gives R606,AB >28.25 (2 upper limit) and H160,AB = 25.73±0.20. In both cases, we fitted a model point-spread function (psf) and estimated the errors from the variance of the flux at a large number of locations chosen to ha ...
Are Gamma-Ray Bursts good Star Formation Indicators?
... Since long-duration gamma-ray bursts (GRBs) are associated with the deaths of massive stars, the are also indicators of star formation activity. Advantages they have over conventional methods are that they are extremely bright, and hence visible to high redshifts, and detectable in gamma-rays throug ...
... Since long-duration gamma-ray bursts (GRBs) are associated with the deaths of massive stars, the are also indicators of star formation activity. Advantages they have over conventional methods are that they are extremely bright, and hence visible to high redshifts, and detectable in gamma-rays throug ...
Constraining the instrinsic energy of GRB events
... 2 sec , for this value both the absorptive and scattering optical depths are very large and it is extremely difficult to understand how photons about the pair creation threshold escape from the emitting region, located close to the compact source. This problem was resolved by invoking relativistic o ...
... 2 sec , for this value both the absorptive and scattering optical depths are very large and it is extremely difficult to understand how photons about the pair creation threshold escape from the emitting region, located close to the compact source. This problem was resolved by invoking relativistic o ...
Milky Way
... • Long gamma-ray bursts (> 2 sec): Found in young, star forming regions. Some are clearly massive supernovae (hypernovae?) because spectra are seen. • Short gamma-ray bursts (< 2 sec): Found in young and old regions. Thought to be two merging neutron stars or a neutron star plus a black hole. ...
... • Long gamma-ray bursts (> 2 sec): Found in young, star forming regions. Some are clearly massive supernovae (hypernovae?) because spectra are seen. • Short gamma-ray bursts (< 2 sec): Found in young and old regions. Thought to be two merging neutron stars or a neutron star plus a black hole. ...
Presentation available here - Lunar and Planetary Institute
... TIFF (Uncompressed) decompressor are needed to see this picture. ...
... TIFF (Uncompressed) decompressor are needed to see this picture. ...
Spectra of Afterglows
... arrange detailed observations. They occur at random spatially and temporally, difficult to prepare in advance. Except prompt gamma-ray (and maybe weak X-ray), no counterpart on other wave band was found before 1997, difficult to be identified through other wave band with other objects of known d ...
... arrange detailed observations. They occur at random spatially and temporally, difficult to prepare in advance. Except prompt gamma-ray (and maybe weak X-ray), no counterpart on other wave band was found before 1997, difficult to be identified through other wave band with other objects of known d ...
Gamma Ray Bursts - University of Arizona
... Radio shows A definite Break between GRBs and Normal type Ib/Ic SNe! At Most, 5% Of supernovae Are GRBs (Berger et al. ...
... Radio shows A definite Break between GRBs and Normal type Ib/Ic SNe! At Most, 5% Of supernovae Are GRBs (Berger et al. ...
Slide 1
... UV capability which is not possible from the ground. It cannot be clouded out. It is also much more sensitive than any other quick reaction telescope. The UVOT also enables optimal ground based observations by providing rapid optical images of the GRB field so that any optical or IR counterpart can ...
... UV capability which is not possible from the ground. It cannot be clouded out. It is also much more sensitive than any other quick reaction telescope. The UVOT also enables optimal ground based observations by providing rapid optical images of the GRB field so that any optical or IR counterpart can ...
Lecture 18 Gamma-Ray Bursts
... The bursts were either on the outskirts of galaxies or in old galaxies with low star formation rate There was no accompanying supernova The redshifts were much lower than for the long soft bursts and thus the total energy was about two orders of magnitude less (because they are shorter as well as cl ...
... The bursts were either on the outskirts of galaxies or in old galaxies with low star formation rate There was no accompanying supernova The redshifts were much lower than for the long soft bursts and thus the total energy was about two orders of magnitude less (because they are shorter as well as cl ...
Part B
... sky suggesting extragalactic origin. • New GRBs discovered at rate of about one per day. ...
... sky suggesting extragalactic origin. • New GRBs discovered at rate of about one per day. ...
The Danger of Deadly Cosmic Explosions
... • Brightest X-Ray burst – damaged satellites – affected radio. ...
... • Brightest X-Ray burst – damaged satellites – affected radio. ...
Modeling the Spectral Energy Distributions and Variability
... Models of GRBs (II) Black-hole – neutron-star merger: Black hole and neutron star (or 2 neutron stars) orbiting each other in a binary system ...
... Models of GRBs (II) Black-hole – neutron-star merger: Black hole and neutron star (or 2 neutron stars) orbiting each other in a binary system ...
Skynet
... Bright Enough to See Without a Telescope! The Most Luminous Event Ever Observed...30,000,000,000,000,000,000 (30 Billion Billion) Times the Luminosity of the Sun, or as Bright as 100 Million Galaxies! Very Easy to Make Scientific Observations with a Small Telescope ...
... Bright Enough to See Without a Telescope! The Most Luminous Event Ever Observed...30,000,000,000,000,000,000 (30 Billion Billion) Times the Luminosity of the Sun, or as Bright as 100 Million Galaxies! Very Easy to Make Scientific Observations with a Small Telescope ...
Today`s Powerpoint
... Gamma-ray Bursts: some pulsars produce bursts of gamma-rays, called Soft Gamma-Ray Repeaters or SGRs ...
... Gamma-ray Bursts: some pulsars produce bursts of gamma-rays, called Soft Gamma-Ray Repeaters or SGRs ...
The Danger of Deadly Cosmic Explosions
... • Narrow beam, confined over galactic distances. • We see GRB in distant galaxies that have most radiation at high energies…. penetrates even underground and underseas. • Equivalent to 1 kiloton TNT / km2 over earth surface, and clearly kills everything immediately exposed. • Longer term destroys at ...
... • Narrow beam, confined over galactic distances. • We see GRB in distant galaxies that have most radiation at high energies…. penetrates even underground and underseas. • Equivalent to 1 kiloton TNT / km2 over earth surface, and clearly kills everything immediately exposed. • Longer term destroys at ...
Slides from the fourth lecture
... Swift, we began imaging the GRB field 8 minutes after the burst and continued for the following 8 days. No convincing optical/infrared candidate afterglow or supernova was found for the object. We present a re-analysis of the XRT afterglow and find an absolute position that is ~4" to the west of the ...
... Swift, we began imaging the GRB field 8 minutes after the burst and continued for the following 8 days. No convincing optical/infrared candidate afterglow or supernova was found for the object. We present a re-analysis of the XRT afterglow and find an absolute position that is ~4" to the west of the ...
Refusing to Go Quietly: GRBs and Their Progenitors
... • If they are very far, their energies may be stupendous....something like the rest mass of the sun being turned into gamma-rays! ...
... • If they are very far, their energies may be stupendous....something like the rest mass of the sun being turned into gamma-rays! ...
Relativistic jets in microquasars, AGN and GRBs
... V ~ 27 km/s ~ 2 M were blown away Linear momentum = 430 M km/s, as in runaway neutron stars THE RELATIVISTIC STAR IN LSI +61 303 WAS BORN ...
... V ~ 27 km/s ~ 2 M were blown away Linear momentum = 430 M km/s, as in runaway neutron stars THE RELATIVISTIC STAR IN LSI +61 303 WAS BORN ...
Word doc - UC-HiPACC - University of California, Santa Cruz
... ‘The burst of the century’ “This was the burst of the century!” exclaimed James A. Wren, an engineer at Los Alamos National Laboratory and co-author of one of the papers. Indeed, GRB 130427A (as it is now called) was the most powerful gamma-ray burst and the second-brightest optical flash measured i ...
... ‘The burst of the century’ “This was the burst of the century!” exclaimed James A. Wren, an engineer at Los Alamos National Laboratory and co-author of one of the papers. Indeed, GRB 130427A (as it is now called) was the most powerful gamma-ray burst and the second-brightest optical flash measured i ...
ppt
... Laplace (1798) – “A luminous star, of the same density as the Earth, and whose diameter should be two hundred and fifty times larger than that of the Sun, would not, in consequence of its attraction, allow any of its rays to arrive at us; it is therefore possible that the largest luminous bodies in ...
... Laplace (1798) – “A luminous star, of the same density as the Earth, and whose diameter should be two hundred and fifty times larger than that of the Sun, would not, in consequence of its attraction, allow any of its rays to arrive at us; it is therefore possible that the largest luminous bodies in ...
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.