here - Event Horizon Telescope
... If a disk of gas and dust surrounds a black hole, the event horizon should look like a dark silhouette, surrounded by the glow of accreting material and framed with streaks of light. The silhouette effect happens for two reasons. First, light is fighting to survive. The black hole sits in the midst ...
... If a disk of gas and dust surrounds a black hole, the event horizon should look like a dark silhouette, surrounded by the glow of accreting material and framed with streaks of light. The silhouette effect happens for two reasons. First, light is fighting to survive. The black hole sits in the midst ...
X-ray spectrometer
... * The duration and cadence of monitoring will become more clear once GLAST is in orbit * Sensitivity: for the brightest GLAST blazars, average 10-80 keV flux is ~ 10-11 erg cm-2 s-1 -> we should get about 0.1 NuSTAR count/s -> Dflux ~ 7% , Da~0.1 in a NuSTAR orbit * Probably will do “continuous look ...
... * The duration and cadence of monitoring will become more clear once GLAST is in orbit * Sensitivity: for the brightest GLAST blazars, average 10-80 keV flux is ~ 10-11 erg cm-2 s-1 -> we should get about 0.1 NuSTAR count/s -> Dflux ~ 7% , Da~0.1 in a NuSTAR orbit * Probably will do “continuous look ...
Publisher: Emily Barrosse Acquisitions Editor: Kelley Tyner
... to the white dwarf by its companion, causing the white dwarf to reach the Chandrasekhar limit of 1.4 solar masses, it can no longer support itself. The white dwarf then explodes in a runaway chain of nuclear-fusion reactions. Such supernovae become as bright as 10 billion Suns, the energy coming fro ...
... to the white dwarf by its companion, causing the white dwarf to reach the Chandrasekhar limit of 1.4 solar masses, it can no longer support itself. The white dwarf then explodes in a runaway chain of nuclear-fusion reactions. Such supernovae become as bright as 10 billion Suns, the energy coming fro ...
My power point presentation on spectroscopy of stars (ppt file)
... • We can hardly see any surface details from the solar system, except for our own Sun • The interior of a star is even more hidden than the surface layers • Essentially the only information a star sends to us is its electromagnetic radiation • Can we dissect the radiation from a star to find out any ...
... • We can hardly see any surface details from the solar system, except for our own Sun • The interior of a star is even more hidden than the surface layers • Essentially the only information a star sends to us is its electromagnetic radiation • Can we dissect the radiation from a star to find out any ...
PDF file - Research in Astronomy and Astrophysics
... We thus infer the formation of the jet is possibly after the evacuation of ambient materials by robust stellar winds from the central OB stars. The energy source could have been formed in dense cloud cores or even swept-up cloud materials following the formation of the HII region and is among the ve ...
... We thus infer the formation of the jet is possibly after the evacuation of ambient materials by robust stellar winds from the central OB stars. The energy source could have been formed in dense cloud cores or even swept-up cloud materials following the formation of the HII region and is among the ve ...
Solutions
... by the newly formed OB Association stars that emit most of their energy as high-energy short-wavelength hardUV photons. The photons from the OB Association stars “power up” the HII region and keep it fluorescing. Thus the OB Association forms first and then the HII region is created around the vicin ...
... by the newly formed OB Association stars that emit most of their energy as high-energy short-wavelength hardUV photons. The photons from the OB Association stars “power up” the HII region and keep it fluorescing. Thus the OB Association forms first and then the HII region is created around the vicin ...
celestial sphere
... PURPOSE: To compare the horizon and equatorial coordinate systems and to learn how to determine sidereal time. To make use of a celestial globe in understanding the basic coordinate systems. PROCEDURE: Making use of the celestial globe, answer the questions in this lab pertaining to the horizon and ...
... PURPOSE: To compare the horizon and equatorial coordinate systems and to learn how to determine sidereal time. To make use of a celestial globe in understanding the basic coordinate systems. PROCEDURE: Making use of the celestial globe, answer the questions in this lab pertaining to the horizon and ...
Quasars: Back to the Infant Universe
... close to us or because they’re intrinsically luminous? 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 imp ...
... close to us or because they’re intrinsically luminous? 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 imp ...
Rotation
... the star enters a phase of rapid Wolf-Rayet mass loss that does greatly affect everything – the explosion, light curve, nucleosynthesis and remnant properties. A massive hydrogen envelope may also make the star more difficult to explode because of fall back. 3) Mass loss sets an upper bound to the l ...
... the star enters a phase of rapid Wolf-Rayet mass loss that does greatly affect everything – the explosion, light curve, nucleosynthesis and remnant properties. A massive hydrogen envelope may also make the star more difficult to explode because of fall back. 3) Mass loss sets an upper bound to the l ...
Pp 263-266 - Gravity From The Ground Up
... neutron stars to form in the first place. The maximum mass is a property of nuclear physics and general relativity. The Chandrasekhar mass depends on Newtonian gravity and atomic physics. We could imagine a Universe in which the nuclear repulsive core was smaller, so that neutron stars were denser a ...
... neutron stars to form in the first place. The maximum mass is a property of nuclear physics and general relativity. The Chandrasekhar mass depends on Newtonian gravity and atomic physics. We could imagine a Universe in which the nuclear repulsive core was smaller, so that neutron stars were denser a ...
MACHOs
... total number of MACHOs = total number of machos in one section times the number of sections of 840 days #6 times average mass of MACHO from the 8 observed events to find the total mass of MACHOs in universe i. WE GOT 6.92 x 10^47, which is 10^5 bigger than the total mass of the universe ...
... total number of MACHOs = total number of machos in one section times the number of sections of 840 days #6 times average mass of MACHO from the 8 observed events to find the total mass of MACHOs in universe i. WE GOT 6.92 x 10^47, which is 10^5 bigger than the total mass of the universe ...
Killer Skies
... When modern astronomers turned their telescopes to the location of the guest star, they found a peculiar nebula—now known as the Crab Nebula. The Crab Nebula is called so for its many-legged shape. The ‘legs’ are filaments of gas that are moving away from the site of the explosion at about 1,400 km/ ...
... When modern astronomers turned their telescopes to the location of the guest star, they found a peculiar nebula—now known as the Crab Nebula. The Crab Nebula is called so for its many-legged shape. The ‘legs’ are filaments of gas that are moving away from the site of the explosion at about 1,400 km/ ...
part4.
... “faced” by the infalling dust i.e. just r 2 , where r is the radius of the star. But the dust is accreted not only due to motion of the star through the cloud, but also due to gravitation of the star. Let’s see how. To simplify the matters, let’s go to the frame of reference of the moving star. ...
... “faced” by the infalling dust i.e. just r 2 , where r is the radius of the star. But the dust is accreted not only due to motion of the star through the cloud, but also due to gravitation of the star. Let’s see how. To simplify the matters, let’s go to the frame of reference of the moving star. ...
Chapter 13
... Other important properties of neutron stars (beyond mass and size): • Rotation – as the parent star collapses, the neutron core spins very rapidly, conserving angular momentum. Typical periods are fractions of a second. • Magnetic field – again as a result of the collapse, the neutron star’s magneti ...
... Other important properties of neutron stars (beyond mass and size): • Rotation – as the parent star collapses, the neutron core spins very rapidly, conserving angular momentum. Typical periods are fractions of a second. • Magnetic field – again as a result of the collapse, the neutron star’s magneti ...
Slide 1
... For Earth Fg = 7, σρ =10 g cm-2, n = 2x10-7 s-1, ρp = 4.5 g cm-3, growth time 2x107 yr, or better 108 yr, if depletion of planetesimals in later stage of accretion is considered. Problems with outer planets. For Jupiter σρ = 3 g cm-2, heavy element mass 15-20 Earth masses, growth time > 108 yr. Surf ...
... For Earth Fg = 7, σρ =10 g cm-2, n = 2x10-7 s-1, ρp = 4.5 g cm-3, growth time 2x107 yr, or better 108 yr, if depletion of planetesimals in later stage of accretion is considered. Problems with outer planets. For Jupiter σρ = 3 g cm-2, heavy element mass 15-20 Earth masses, growth time > 108 yr. Surf ...
The Milky Way Galaxy
... diameter and about 2000 light-years thick, with a high concentration of interstellar dust and gas. It contains around 200 billion stars. Interstellar dust obscures our view into the plane of the galactic disk at visual wavelengths. However, hydrogen clouds can be detected beyond this dust by the 21- ...
... diameter and about 2000 light-years thick, with a high concentration of interstellar dust and gas. It contains around 200 billion stars. Interstellar dust obscures our view into the plane of the galactic disk at visual wavelengths. However, hydrogen clouds can be detected beyond this dust by the 21- ...
Complete the “Assess Your Understanding” including
... was compressed into an extremely small volume. About 14 billion years ago, a sudden event called “the big bang” sent all of the matter and energy outward in all directions. As the universe expanded, some of the matter gathered into clumps because of gravity that evolved into galaxies. Today, the uni ...
... was compressed into an extremely small volume. About 14 billion years ago, a sudden event called “the big bang” sent all of the matter and energy outward in all directions. As the universe expanded, some of the matter gathered into clumps because of gravity that evolved into galaxies. Today, the uni ...
Sun, Moon, Earth,
... star in an area the size of a city. – Some give off regular pulses of radio waves and are called pulsars. (these were originally called LGMs). ...
... star in an area the size of a city. – Some give off regular pulses of radio waves and are called pulsars. (these were originally called LGMs). ...
Chapter 22 PowerPoint
... • Neutron stars are very dense, spin rapidly, and have intense magnetic fields. • Neutron stars may appear as pulsars due to the lighthouse effect. • A neutron star in a close binary may become an X-ray burster or a millisecond pulsar. • Gamma-ray bursts are probably due to two neutron stars collidi ...
... • Neutron stars are very dense, spin rapidly, and have intense magnetic fields. • Neutron stars may appear as pulsars due to the lighthouse effect. • A neutron star in a close binary may become an X-ray burster or a millisecond pulsar. • Gamma-ray bursts are probably due to two neutron stars collidi ...
Dynamics
... as they accrete some of this abundant gas supply. In the final stage of the merger, when the nuclei of the two galaxies have spiralled very close together, the black holes can have a significant impact on the distribution of stars in their vicinity. Indeed, the merger leads to the formation of a bin ...
... as they accrete some of this abundant gas supply. In the final stage of the merger, when the nuclei of the two galaxies have spiralled very close together, the black holes can have a significant impact on the distribution of stars in their vicinity. Indeed, the merger leads to the formation of a bin ...
The Physics of Massive Star Formation
... accretion rate very well fit by with BH a known function of Mach number, region size From this, compute mass gained by accreting unbound gas: ...
... accretion rate very well fit by with BH a known function of Mach number, region size From this, compute mass gained by accreting unbound gas: ...
The accretion properties of the intermediate mass Herbig Ae/Be stars
... Emission line luminosities correlate with accretion luminosity. Can be used as accretion diagnostic Lacc determination much easier than using UV excess Extended the number of calibrated lines to entire XShooter spectral range Fairlamb+ 2016, subm. Mendigutia+2011, Garcia-Lopez+ 2005, Muzerolle+2004 ...
... Emission line luminosities correlate with accretion luminosity. Can be used as accretion diagnostic Lacc determination much easier than using UV excess Extended the number of calibrated lines to entire XShooter spectral range Fairlamb+ 2016, subm. Mendigutia+2011, Garcia-Lopez+ 2005, Muzerolle+2004 ...
Cygnus X-1
Cygnus X-1 (abbreviated Cyg X-1) is a well-known galactic X-ray source, thought to be a black hole, in the constellation Cygnus. It was discovered in 1964 during a rocket flight and is one of the strongest X-ray sources seen from Earth, producing a peak X-ray flux density of 6977229999999999999♠2.3×10−23 Wm−2 Hz−1 (7003230000000000000♠2.3×103 Jansky). Cygnus X-1 was the first X-ray source widely accepted to be a black hole and it remains among the most studied astronomical objects in its class. The compact object is now estimated to have a mass about 14.8 times the mass of the Sun and has been shown to be too small to be any known kind of normal star, or other likely object besides a black hole. If so, the radius of its event horizon is about 7004440000000000000♠44 km.Cygnus X-1 belongs to a high-mass X-ray binary system about 7019574266339685654♠6070 ly from the Sun that includes a blue supergiant variable star designated HDE 226868 which it orbits at about 0.2 AU, or 20% of the distance from the Earth to the Sun. A stellar wind from the star provides material for an accretion disk around the X-ray source. Matter in the inner disk is heated to millions of degrees, generating the observed X-rays. A pair of jets, arranged perpendicular to the disk, are carrying part of the energy of the infalling material away into interstellar space.This system may belong to a stellar association called Cygnus OB3, which would mean that Cygnus X-1 is about five million years old and formed from a progenitor star that had more than 7001400000000000000♠40 solar masses. The majority of the star's mass was shed, most likely as a stellar wind. If this star had then exploded as a supernova, the resulting force would most likely have ejected the remnant from the system. Hence the star may have instead collapsed directly into a black hole.Cygnus X-1 was the subject of a friendly scientific wager between physicists Stephen Hawking and Kip Thorne in 1975, with Hawking betting that it was not a black hole. He conceded the bet in 1990 after observational data had strengthened the case that there was indeed a black hole in the system. This hypothesis has not been confirmed due to a lack of direct observation but has generally been accepted from indirect evidence.