Galaxy Evolution
... as a function of M500 (bottom axis) and velocity dispersion (top axis). X-ray gas mass fractions from Vikhlinin et al. (2006; circles) and Gastaldello et al. (2006; triangles) and the stellar mass fractions ( BCG +ICL+galaxies; squares) for systems in our sample with masses that overlap the range sh ...
... as a function of M500 (bottom axis) and velocity dispersion (top axis). X-ray gas mass fractions from Vikhlinin et al. (2006; circles) and Gastaldello et al. (2006; triangles) and the stellar mass fractions ( BCG +ICL+galaxies; squares) for systems in our sample with masses that overlap the range sh ...
21structure1i
... There is no single method that can be used to find the distances to all objects We use many methods, each building on the other Called the cosmic distance ladder ...
... There is no single method that can be used to find the distances to all objects We use many methods, each building on the other Called the cosmic distance ladder ...
Document
... The observation that there are few spiral galaxies in areas of high galaxy density. ...
... The observation that there are few spiral galaxies in areas of high galaxy density. ...
Universal redshift, the Hubble constant The cosmic background
... At some point they meet with R. Dicke and P. Peebles and find out, what they see is something important. ...
... At some point they meet with R. Dicke and P. Peebles and find out, what they see is something important. ...
file - University of California San Diego
... The forest, Burbidge notes, may represent light not from the quasar itself but from diffuse gas clouds that lie along our line of sight to the quasar and absorb some of its spectrum. "These gas clouds may be in a primordial region, perhaps evolving into a cluster of galaxies around the quasar," Burb ...
... The forest, Burbidge notes, may represent light not from the quasar itself but from diffuse gas clouds that lie along our line of sight to the quasar and absorb some of its spectrum. "These gas clouds may be in a primordial region, perhaps evolving into a cluster of galaxies around the quasar," Burb ...
Los Angeles Astronomical - LIGO
... But, what causes the mysterious force in Newtons theory ? Although the equation explains nature very well, the underlying mechanism creating the force is not explained ! ...
... But, what causes the mysterious force in Newtons theory ? Although the equation explains nature very well, the underlying mechanism creating the force is not explained ! ...
POISE AND EVOLUTION OF THE GALAXY : STRUCTURE ,
... the whole, within the last 2000 years. The reason is clear : this is just an instant phenomenon, with absolutely no warning before, and as soon disappearing with only quite ephemeral fossil remnants testifying. There is however, nowadays, a current opinion that SUPERNOVAE should actually be many tim ...
... the whole, within the last 2000 years. The reason is clear : this is just an instant phenomenon, with absolutely no warning before, and as soon disappearing with only quite ephemeral fossil remnants testifying. There is however, nowadays, a current opinion that SUPERNOVAE should actually be many tim ...
Active Galaxies
... •Galaxies that emit most of their light in IR - LIR > 1012 Lsun •Few in local universe; most beyond z > 1 •Nearly all are undergoing mergers - forming E’s •IR light is likely a combination of dust reprocessed AGN emission and starbursts. •Some AGN may manifest as ULIRGs during different stages of ...
... •Galaxies that emit most of their light in IR - LIR > 1012 Lsun •Few in local universe; most beyond z > 1 •Nearly all are undergoing mergers - forming E’s •IR light is likely a combination of dust reprocessed AGN emission and starbursts. •Some AGN may manifest as ULIRGs during different stages of ...
Chapter 1 Our Place in the Universe
... Observations of galaxies show that the entire universe is expanding, the average distance between galaxies is increasing with time. This means that galaxies ( or at least matter) must have been close together in the past. If we go back far enough, all the matter was concentrated in a small radius fr ...
... Observations of galaxies show that the entire universe is expanding, the average distance between galaxies is increasing with time. This means that galaxies ( or at least matter) must have been close together in the past. If we go back far enough, all the matter was concentrated in a small radius fr ...
PSR J1833-1034
... – No X-rays pulsation detection – It is a young pulsar, maybe the youngest in our Galaxy – Its gamma-rays light curve show two peaks separated by ~0.435 in phase and also the Interpulse – The ratio P1/P2 decrease with increasing energies – From the SED seems that the FERMI-LAT data points are well c ...
... – No X-rays pulsation detection – It is a young pulsar, maybe the youngest in our Galaxy – Its gamma-rays light curve show two peaks separated by ~0.435 in phase and also the Interpulse – The ratio P1/P2 decrease with increasing energies – From the SED seems that the FERMI-LAT data points are well c ...
Searching for Dwarf Galaxies and Population III Star
... images that reveal the most massive star-forming galaxies and proto-clusters of galaxies at z > 7. We will identify the most luminous at z ~ 7.7, where Lyman falls in an atmospheric window between night sky lines, and conduct a narrowband imaging search with IRMS. Using current state-of-the-art mo ...
... images that reveal the most massive star-forming galaxies and proto-clusters of galaxies at z > 7. We will identify the most luminous at z ~ 7.7, where Lyman falls in an atmospheric window between night sky lines, and conduct a narrowband imaging search with IRMS. Using current state-of-the-art mo ...
SGR 1900+14
... • Total (isotropic) energy release>1046 erg (Peak) and 5x1043 erg (tail) Some comparisons: GRB prompt emission peak fluxes: 10-8-10-3 ergs/cm2 s X-ray afterglows of long bursts: ~10-11 – 10-13 ergs/cm2 s Previous giant flares: ~10-3 ergs/cm2 s Typical SGR bursts: 10-9 – 10-6 ergs/cm2 s ...
... • Total (isotropic) energy release>1046 erg (Peak) and 5x1043 erg (tail) Some comparisons: GRB prompt emission peak fluxes: 10-8-10-3 ergs/cm2 s X-ray afterglows of long bursts: ~10-11 – 10-13 ergs/cm2 s Previous giant flares: ~10-3 ergs/cm2 s Typical SGR bursts: 10-9 – 10-6 ergs/cm2 s ...
Ch. 15 Notes
... *Black holes are at least three times more massive than our sun but less than 10 km across ...
... *Black holes are at least three times more massive than our sun but less than 10 km across ...
On the composition of GRBs` Collapsar jets
... Kouveliotou et al. 1993; Nakar 2007; BNPS13). We will use this feature in the following to distinguish between the two populations. (ii) The observed redshift distribution of SGRBs is different as was pointed out already in 1995 by Cohen & Piran (1995), using V/Vmax , and confirmed later by direct r ...
... Kouveliotou et al. 1993; Nakar 2007; BNPS13). We will use this feature in the following to distinguish between the two populations. (ii) The observed redshift distribution of SGRBs is different as was pointed out already in 1995 by Cohen & Piran (1995), using V/Vmax , and confirmed later by direct r ...
PowerPoint Presentation - Research in observational
... short time. • LBVs might be the most massive stars where radiation pressure is at the limit for stellar stability. • We observe these LBV nebulae around WR stars. • Sometime, they have bipolar shapes (e.g., e Car) and a binary cause is suspected. ...
... short time. • LBVs might be the most massive stars where radiation pressure is at the limit for stellar stability. • We observe these LBV nebulae around WR stars. • Sometime, they have bipolar shapes (e.g., e Car) and a binary cause is suspected. ...
UTAustin2 - LIGO
... Known sources -- Supernovae & GRBs » Coincidence with observed electromagnetic observations. » No close supernovae occurred during the first science run » Second science run – We are analyzing the recent very bright and close GRB030329 NO RESULT YET ...
... Known sources -- Supernovae & GRBs » Coincidence with observed electromagnetic observations. » No close supernovae occurred during the first science run » Second science run – We are analyzing the recent very bright and close GRB030329 NO RESULT YET ...
MICROQUASARS
... PSR B1259-63, LS 5039 & LSI +61 303 have compact objects with M < 4 MSUN Time variability & x-ray spectrum of LSI +61 303 resemble those of young pulsars LSI +61 303 is a Be star like PSR B1259-63 & all known Be/X-ray binary are NSs But does not satisfactorily fit the GeV & radio wavelength fluxes i ...
... PSR B1259-63, LS 5039 & LSI +61 303 have compact objects with M < 4 MSUN Time variability & x-ray spectrum of LSI +61 303 resemble those of young pulsars LSI +61 303 is a Be star like PSR B1259-63 & all known Be/X-ray binary are NSs But does not satisfactorily fit the GeV & radio wavelength fluxes i ...
How Big is the Universe
... telescope, an instrument used to view distant objects. He saw there were more stars in ...
... telescope, an instrument used to view distant objects. He saw there were more stars in ...
Active Galactic Nuclei
... of times brighter than its surrounding galaxy. On the other hand, if the black hole is not accreting, it will be invisible. ...
... of times brighter than its surrounding galaxy. On the other hand, if the black hole is not accreting, it will be invisible. ...
Crowdclass Supplemental Materials - Doris Jung
... • Galaxy collisions are rare events that don’t happen very frequently throughout the universe’s history. • Since galaxies are so large, collisions with other galaxies have very little influence on its shape and features. • (*) When galaxies merge, the turbluent gas inflowing into the interaction reg ...
... • Galaxy collisions are rare events that don’t happen very frequently throughout the universe’s history. • Since galaxies are so large, collisions with other galaxies have very little influence on its shape and features. • (*) When galaxies merge, the turbluent gas inflowing into the interaction reg ...
astro-ph/0504597 PDF
... Supernova is one of the most violent phenomena that occur in the universe. Supernovae are really bright – about 10 billion times as luminous as the Sun. They tend to fade over months or years. The energy output of a supernova surpasses that of the galaxy as a whole! When one such occurs in our own G ...
... Supernova is one of the most violent phenomena that occur in the universe. Supernovae are really bright – about 10 billion times as luminous as the Sun. They tend to fade over months or years. The energy output of a supernova surpasses that of the galaxy as a whole! When one such occurs in our own G ...
The Unified Theory of Stellar Evolution
... and electrons combine and form hydrogen, the lowest element on the periodic table. [In many cases, the plasmas of elementary particles were ejected during past supernova explosions.] A new star is ...
... and electrons combine and form hydrogen, the lowest element on the periodic table. [In many cases, the plasmas of elementary particles were ejected during past supernova explosions.] A new star is ...
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.