... Bad Astronomy . ... Bitesize Astronomy . ... Last week's Snack talked about how black holes can affect the environment around them in such a way as to be very bright . ... It's a common misconception that black holes always have matter swirling into them. ... As this matter gets closer and closer to the black hole it piles up and a large, fairly flat disk forms. This is called the accretion disk , because matter from this disk accretes (that is, falls in) on the black hole. ... 2008 Phil Plait. ...

Astronomy Picture of the Day . SN 1006: Historys Brightest Supernova . ... 17.03.2003 . ... AURA , NOAO , NSF Explanation: Suddenly, in the year 1006 AD, a new star appeared in the sky. ... It turns out SN 1006 likely achieved an apparent visual magnitude of -7.5, making it the brightest supernova on record. ... 1997 1998 . ... NASA Web Site Statements, Warnings, and Disclaimers . ... SN 1006 Supernova Remnant . X rays from Supernova Remnant SN 1006 . ... SN 1006: Supernova Remnant in X Rays . ...

... 2003 March 17 . SN 1006: History's Brightest Supernova . ... Explanation: Suddenly, in the year 1006 AD, a new star appeared in the sky. ... Modern observations have been used to measure the speed of the still-expanding shock wave , allowing a better estimate of its distance and hence a better estimate of the true brightness of the supernova . It turns out SN 1006 likely achieved an apparent visual magnitude of -7.5, making it the brightest supernova on record. ... About APOD | ...

... Problem 1.1: (4pts) We want to use supernovae as a standard candle to measure luminosity distance as a function of redshift in order to determine the Hubble Constant. ... Problem 2: In a flat Universe, the luminosity distance to an object at redshift z, in a universe made up of i forms of matter each with an equation of state wi and density, i is given by ,1 / 2 z & ) c 3 + 3wi DL = (1 + z) # dz"(% $i (1 + z") + H0 'i * 0 2.1 (5 pts). ... Assume the universe is radiation dominated the whole time. ...

True Color Image Gallery: Galactic SNR | Magellanic Cloud SNR . ... Chandra Proposer's Guide pile up section ] During frame readout, the ACIS CCDs take 40 microsec to (parallel) transfer the charge by one pixel. As a result of this, each frame readout, each pixel is exposed for 40 microsec to a source (plus cosmic X-ray background) at each location along its column. ... Note also that the image does not just trail, it extends along the whole column. ... Chandra Supernova Remnant Catalog . ...

. Please standby and you will be automatically connected to the new location of the unframed Supernova page. Or, click on the link above. If you have questions or problems, please email me at David Bishop dbishop@vhdl.org . Last modified: Mon Aug 27 12:40:15 EDT 2001

... To be read in conjunction with Section 4.11 of the WFPC2 Instrument Handbook , -Version 4.0. ... 1 The second study found evidence that CTE loss for faint stars has increased with time (Whitmore, 1998). The primary observational consequence of CTE loss is that a point source at the top of the chip appears to be fainter than if observed at the bottom of the chip, due to the loss of electrons as the star is read out down the chip (see Figure 1 ). ... Last updated: 06/16/98 10:38:00 . ...

Next: Basic Properties Up: R Coronae Borealis Stars Previous: Introduction . RCB stars are named after a star just visible to the naked eye in the constellation of Corona Borealis. RCrB was discovered by Edward Pigott, an English amateur astronomer, who had been observing a star in the `Northern Crown' for over a decade. ... Since 1795, other RCB stars have been discovered and their properties have been carefully observed. ...

Next: Results and Discussion Up: Evolution of Supernova Explosion Previous: - Dependence for the . In order to construct the - dependence for supernova explosions, we calculated separately the m ( z ) in the R band and N ( z ) taking the cosmological and evolutionary effects into account. ... where n(t) is the SN rate as a function of age of the galaxy, t(z) is the age of the galaxy as a function of its redshift, and is the density of galaxies in the Universe. ...

Galaxies are diffuse objects which are imaged against a background of finite brightness and noise. Galaxies which have the maximum contrast with respect to this background are the ones that are first discovered. ... These galaxies have been missed to date but active surveys for them are underway. ... In this page we present several examples of these newly discovered Low Surface Brightness galaxies as well as examples of high surface brightness galaxies. ...

... Since the fast mode window is necessarily small, the source PSF fills much of the window (clearly evident for bright sources). ... As such, the source and background extraction apertures may be truncated by the window. ... While often there will be only one object in the image, one should check for spurious detections which could affect the analysis of the target source and also for missed sources or prominent objects in the window, which may contaminate the target. ...

B?rbel Koribalski (ATNF) + HIPASS and ZOA teams . The properties shown below were derived from the measurd HI properties. Displayed here are the Local Group velocities of all sources from -300 to +8000 km/s (bins are 100 km/s). Displayed here are the distances of all sources (assuming Ho = 75 km/s/Mpc). ... Displayed here are the HI masses of all sources (assuming point source distribution). Extended galaxies and pairs/groups need to be re-measured. ...

... SEARCH ASP SITE: Match ALL words Match ANY word . ... ASP Conference Series . ... Accidental Astrophysics: The Devil's In the Magnitudes, Part II . ... The star second to the Sun in brilliance is Sirius. ... Recall the magnitude system, passed down to us through a hundred generations of sky watchers, as a means of quantifying stellar brightness ("Accidental Astrophysics," May/June, p. 9). ... Yes, it is a magnitude difference, but that difference is due to the distance between us and the star. ...

... Using a simple 2-D Gaussian Point Spread Function (PSF) on a constant (flat) sky background, I derive a theoretical photometric and astrometric performance model for analytical and digital PSF-fitting stellar photometry. ... The photometric performance is maximized when either the effective background area or the effective-background-level measurement error is minimized. ... An important, but frequently ignored, noise source is the uncertainty of the measurement of the effective background level ( )...

... The explosion of a star as a Supernova is certainly one of the most energetic events observable in the whole universe, and their radiation covers the whole band from radio to gamma-rays, accompanied with neutrino emission. ... Type Ia SNe are supposed to result from mass transfer inside a binary system consisting of a white dwarf star and an evolving giant star, which results in a termonuclear explosion. ... Core-collapse Supernovae . ... For comments please contact: gcresci@arcetri.astro.it . ...

... For spectra a transformation from wavelength to frequency is used to identify spectral regions which follow a power law. This transformation is given by . ... Whereas the transforms mentioned above only perform a non--linear rebinning of the data, the Fourier transform converts a spatial image into the frequency domain. ... As an example of using Fourier transforms to extract information from a frame, an azimuthal intensity profile of the spiral galaxy A0526--16 is shown in Figure . ...

. The Spitzer Space Telescope reveals infrared radiation coming from dust particles heated by the supernova's shock wave. The glow appears brightest just outside the regions seen by Hubble. Four hundred years after the explosion, Kepler's supernova remnant now spans 14 light-years. NASA/ESA/JHU/R. Sankrit and W. Blair

... self-absorption - the absorption of light shining on an object by a process similar to that which produced the light originally; if a cloud emits less light than it absorbs from other clouds behind it, this net loss of light, termed self-absorption , causes the foreground cloud to appear darker than the background field (the term is from spectroscopy, where small absorption dips sometimes occur in larger emission lines, making the latter look as if it is absorbing part of itself) . ... HISA Main ...

Appendix C Radiative Transfer for a Two-Level System This appendix details how to derive the total column density of a linear rigid-rotor molecule, such as CO, from the observed brightness of its rotational transition. ... C.2 Radiative Transfer for a Two-Level System I now consider emission in a two-level system from an upper J + 1 (denoted `u') to lower J (denoted `l') state. ... Spontaneous emission is controlled by the A coefficient, with a rate Aul nu . ... Tex exp(-31. ...

Astronotes Armagh Planetarium's Stellar Blog! ... Colin Johnston . ... Our Galaxy . ... To locate it, look along the imaginary line between the two end stars on the leading edge of the PloughтАЩs blade (Merak and Dubhe) and Polaris (the North Star), the galaxy M82 (also known as the Cigar Galaxy) along with its companion M81, lies just off this line about a third of the way between the Plough and Polaris. €а€аAs usual, the supernova is far brighter than its home galaxy, appearing as an extra star. ...