International Astronomical Union Commission 42 BIBLIOGRAPHY
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Multiwavelength Observations of Accretion in Low-Mass X-Ray Binary Systems Robert I
1 Multiwavelength Observations of Accretion in Low-Mass X-ray Binary Systems Robert I. Hynesa Abstract This work is intended to provide an introduction to multiwavelength observations of low-mass X-ray binaries and the techniques used to ana- lyze and interpret their data. The focus will primarily be on ultraviolet, optical, and infrared observations and their connections to other wave- lengths. The topics covered include: outbursts of soft X-ray transients, accretion disk spectral energy distributions, orbital lightcurves in lumi- nous and quiescent states, super-orbital and sub-orbital variability, line spectra, system parameter determinations, and echo-mapping and other rapid correlated variability. 1.1 Introduction The first X-ray binary to be observed and identified as such was Scorpius X-1 (Giacconi et al., 1962), although several other systems were known as optical stars or novae before this. Within a few years, optical and radio counterparts to Sco X-1 were discovered (Sandage et al., 1966; Andrew and Purton, 1968), and the topic has remained multiwavelength in nature since then. This work is intended to provide an introduction to some of the obser- vational characteristics of X-ray binaries suitable for a graduate student or an advanced undergraduate. My aim was to produce a primer for someone relatively new to the field rather than a comprehensive review. Where appropriate I will also discuss techniques for analysis and inter- a Louisiana State University, Department of Physics and Astronomy, 202 arXiv:1010.5770v1 [astro-ph.HE] 27 Oct 2010 Nicholson Hall, Tower Drive, Baton Rouge, LA 70803, USA 2 R. -
Star Maps: Where Are the Black Holes?
BLACK HOLE FAQ’s 1. What is a black hole? A black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull. There are three kinds of black hole that we have strong evidence for: a. Stellar-mass black holes are the remaining cores of massive stars after they die in a supernova explosion. b. Mid-mass black hole in the centers of dense star clusters Credit : ESA, NASA, and F. Mirabel c. Supermassive black hole are found in the centers of many (and maybe all) galaxies. 2. Can a black hole appear anywhere? No, you need an amount of matter more than 3 times the mass of the Sun before it can collapse to create a black hole. 3. If a star dies, does it always turn into a black hole? No, smaller stars like our Sun end their lives as dense hot stars called white dwarfs. Much more massive stars end their lives in a supernova explosion. The remaining cores of only the most massive stars will form black holes. 4. Will black holes suck up all the matter in the universe? No. A black hole has a very small region around it from which you can't escape, called the “event horizon”. If you (or other matter) cross the horizon, you will be pulled in. But as long as you stay outside of the horizon, you can avoid getting pulled in if you are orbiting fast enough. 5. What happens when a spaceship you are riding in falls into a black hole? Your spaceship, along with you, would be squeezed and stretched until it was torn completely apart as it approached the center of the black hole. -
Understanding the X-Ray Flaring from N Carinae A
To be Submitted to the Astrophysical Journal Understanding the X-ray Flaring from n Carinae A. F. J. Moffat Departement de physique, UniversiM de Montreal, Succursale Centre-Ville, Montreal, QC, H3C V7, and Centre de recherche en astrophysique du Quebec, Canada [email protected] M. F. Corcoranl CRESST and X-ray Astrophysics Laboratory NASA/GSFC, Greenbelt, jWD 20771, USA [email protected] ABSTRACT We quantify the rapid variations in X-ray brightness ( "flares") from the ex- tremely massive colliding wind binary n Carinae seen during the past three or- bital cycles by RXTE. The observed flares tend to be shorter in duration and more frequent as periastron is approached, although the largest ones tend to be roughly constant in strength at all phases. Plausible scenarios include (1) the largest of multi-scale stochastic wind clumps from the LBV component entering and compressing the hard X-ray emitting wind-wind collision (WWC) zone, (2) large-scale corotating interacting regions in the LBV wind sweeping across the WWC zone, or (3) instabilities intrinsic to the WWC zone. The first one appears to be most consistent with the observations, requiring homologously expanding clumps as they propagate outward in the LBV wind and a turbulence-like power- law distribution of clumps, decreasing in number towards larger sizes, as seen in Wolf-Rayet winds. Subject headings: X-rays: stars — stars: early-type — stars: individual (p Car) — stars: LBV 'Universities Space Research Association, 10211 W incopin Circle. Suite 500 Columbia, 1v1D 21044, USA. -2— 1. Introduction The extremely massive binary star rl Carinae consists of a Luminous Blue Variable (LBV) primary (star A) coupled with a hot, fast-wind secondary (star B) which is probably an evolved 0 star (Verner et al. -
The NTT Provides the Deepest Look Into Space 6
The NTT Provides the Deepest Look Into Space 6. A. PETERSON, Mount Stromlo Observatory,Australian National University, Canberra S. D'ODORICO, M. TARENGHI and E. J. WAMPLER, ESO The ESO New Technology Telescope r on La Silla has again proven its extraor- - dinary abilities. It has now produced the "deepest" view into the distant regions of the Universe ever obtained with ground- or space-based telescopes. Figure 1 : This picture is a reproduction of a I.1 x 1.1 arcmin portion of a composite im- age of forty-one 10-minute exposures in the V band of a field at high galactic latitude in the constellation of Sextans (R.A. loh 45'7 Decl. -0' 143. The individual images were obtained with the EMMI imager/spectrograph at the Nas- myth focus of the ESO 3.5-m New Technolo- gy Telescope using a 1000 x 1000 pixel Thomson CCD. This combination gave a full field of 7.6 x 7.6 arcmin and a pixel size of 0.44 arcsec. The average seeing during these exposures was 1.0 arcsec. The telescope was offset between the indi- vidual exposures so that the sky background could be used to flat-field the frame. This procedure also removed the effects of cos- mic rays and blemishes in the CCD. More than 97% of the objects seen in this sub- field are galaxies. For the brighter galax- ies, there is good agreement between the galaxy counts of Tyson (1988, Astron. J., 96, 1) and the NTT counts for the brighter galax- ies. -