Lorimer, Mia Ihm, Krzysztof Belczynski.
Proto-Neutron Star Neutrino Emission. Aimee L. Hungerford, Christopher L. Fryer, Aristotle Socrates, Omer Blaes. Observations of Cooling Neutron Stars. Disks Around Radio Pulsars. Observations of Radio Pulsars.
Radio Pulsar Statistics. Wynn C. Ho, Dong Lai, Alexander Y. Potekhin, Gilles Chabrier. Accretion Disks.
Astrophysics with Lobster Telescopes. Accretion Powered X-Ray Pulsars. Timing Neutron Stars. The Chandra X-Ray Observatory. The Integral Mission. Concluding Remarks. Back Matter Pages About these proceedings Introduction Neutron stars hold a central place in astrophysics, not only because they are made up of the most extreme states of the condensed matter, but also because they are, along with white dwarfs and black holes, one of the stable configurations that stars reach at the end of stellar evolution.
Accretion Gravity astronomy astrophysics stellar. Wilson, and C. Argon, L.
Some relevant expected solid crust properties are shown in Table 1. Sir Martin Ryle, , for the development of aperture synthesis, and Antony Hewish, , for the discovery of pulsars;. Helfand, D. The The condensed state generally requires low temperatures, below the Fermi temperature TF. A, Due to the symmetry of the background, these perturbations can be expanded in terms of tensor harmonics, so that the angular dependence is explicitly separated.
Greenhill, M. Reid, J. Moran, and E. As interesting as the active black holes themselves are the kinds of galaxies that give rise to such activity. Both ALMA and EVLA, with their high resolution and sensitivity, will push the studies of star formation in host galaxies closer to the nuclear region in which the active black hole resides, thus allowing for the interplay between the black hole and nuclear star formation to be assessed. The study of star formation in our Galaxy and in others is one of the primary areas of science done at millimeter wavelengths GHz. Stars form in giant molecular clouds composed primarily of diatomic hydrogen H 2 ; however, H 2 is particularly difficult to detect because it has no permanent dipole moment.
As a result, astronomers use carbon monoxide CO as a proxy for H 2.
CO is collisionally excited by H 2 , and the resultant emission from CO is observable at radio wavelengths. Hence the properties of star-forming gas are commonly measured with radio telescopes. An example of CO emission from a nearby galaxy is shown in Figure 3. CO emission has been detected in many varieties of galaxies, including some with redshifts up to 6. With radio telescopes, it is thus possible to study the properties of star formation in normal galaxies such as our own, in exotic galaxies with vigorous star formation accompanied by accretion onto black holes e.
An important fact about these observations is that, owing to the motions of nearby galaxies and the redshifts of more distant ones, CO emission is rarely observed at or even near the rest frequency. Herrnstein, J. Moran, L.
Greenhill, P. Diamond, M. Inoue, N. Nakai, M. Miyoshi, C. Henkel, and A. The CO, which is tracing star-forming molecular gas, is observed to follow the spiral arms shown in the Hubble Space Telescope optical image of the galaxy right. The image is approximately 40, light-years across. Image courtesy of Space Telescope Science Institute. The nearby Sun is the only star that there is a chance of studying in detail.
Knowledge of the Sun illuminates the understanding of other stars and generally helps place the Sun and its attendant suite of planets into the context of stellar physics and the evolution of stars and planets. There currently is a proposal to build a powerful new instrument, the Frequency Agile Solar Radiotelescope FASR , that would greatly increase the capability of measuring the solar atmosphere over a wide frequency range, at high time and angular resolution. Flares on the surface are explosions connected with the disappearance or reconnection of magnetic fields Figure 3.
Strong bursts of. For size comparison, Earth is shown as the small blue circle. The flare started with an eruption of twisted magnetic field through the surface. The magnetic field loop is rising rapidly through the corona and will separate from the Sun to form a coronal mass ejection CME.
The inset shows other active regions on the face of the Sun. These can strongly disturb the near-Earth environment. There is general agreement that flares and CMEs are magnetic phenomena, but the details are unclear. Space weather refers to the highly variable condition of the plasma that surrounds Earth and extends from the Sun throughout the solar system.
Flares sometimes produce energetic particles that propagate to Earth in a matter of minutes. These energetic particles can be a danger to the personnel and equipment in space vehicles. If it hits Earth, it can cause serious communication disturbances and adversely affect satellites and long-distance high-voltage transmission lines. Much of this study must be done at radio wavelengths, although the radio information is supplemented with data from other wave bands—for example, x-rays measured from a satellite.
Throughout astronomy, in optical and other bands as well as radio, we are entering an era of intense surveillance, variously called transient source astronomy, time domain astronomy, and, more broadly, a new frontier in high energy astrophysics.
The objective is to capture transient phenomena, which currently are enjoying wide attention. Long-known transient phenomena include novae and supernovae, pulses from pulsars, and motions in quasars and galactic nuclei, in addition to solar system phenomena such as eclipses and solar flares. New radio telescopes, such as the ATA, will be used in a repetitive survey mode to search for transient and variable events.
These phenomena are of broad significance and will contribute to the understanding of the life and death cycle of stars; the nature of exotic compact objects such as neutron stars, white dwarfs,. Transient and variable phenomena are typically broadband, occurring at all radio frequencies and on timescales from nanoseconds to years.
Multifrequency, repetitive observations are necessary to characterize the physics of these targets. Among the projected science targets are phenomena connected with explosions of massive stars, which might produce short bursts of powerful radio emission. The discovery of such events could confirm the fundamental picture of what is called the gamma-ray burst phenomenon and provide an independent method for the discovery of distant star-forming galaxies.
Radio studies of the propagation effects that these waves encounter will probe the very tenuous intergalactic medium that constitutes a significant fraction of the baryonic content of the universe. Neutron stars that emit sporadic pulses have been found very recently, and estimates have been made that such stars are abundant in the Galaxy.
These objects are likely providing new insights into physical conditions in neutron star magnetospheres. Magnetic activity on the surfaces of stellar and compact objects belongs to a continuum of activity that includes solar flares. A comprehensive census of this activity and the detection of true solar-like events on other stars will provide important insights into the physics of solar flares as well as identifying conditions suitable for life on extrasolar planets. Repetitive surveying at high time and frequency resolution is a new regime in astronomical phase space —that is, the parameter space representing all possible observations.
In the past, opening such a new regime generally has led to dramatic new, often unexpected, discoveries. Scientists cannot predict what will be found, but on the basis of past experience, they do expect to see new phenomena.
The ability to distinguish between transients of cosmic origin and sporadic radio frequency interference will be a challenging enterprise. The field has thus been responsible for some of the most important astronomical findings to date. As capabilities increase and new observatories come online, radio astronomy is poised to allow scientists to understand the universe in unprecedented ways.
Finding: Radio astronomy has great potential for further fundamental discoveries, including the origins and evolution of the universe, the nature of matter, and life in other solar systems, which will have an enormous impact on our understanding of fundamental physics and the place of humanity in the universe. Radio observatories contain a diverse group of scientific instruments carefully designed and built to observe with the highest sensitivity selected aspects of the radio emission from the many varieties of objects in the universe.