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Supporting material for Lecture 3: Gamma-Ray Bursts and their counterparts Light extinction:

Supporting material for Lecture 3: Gamma-Ray Bursts and their counterparts Light extinction: Atmospheric absorption Galactic extinction by dust and gas. GRBs are brief flashes of soft  -ray radiation (  100 keV), discovered in the 1970’s, the origin of which was not known until 1997.

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Supporting material for Lecture 3: Gamma-Ray Bursts and their counterparts Light extinction:

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  1. Supporting material for Lecture 3: Gamma-Ray Bursts and their counterparts Light extinction: Atmospheric absorption Galactic extinction by dust and gas

  2. GRBs are brief flashes of soft -ray radiation (100 keV), discovered in the 1970’s, the origin of which was not known until 1997 CGRO-BATSE

  3. Early Multiwavelength Counterparts (z = 0.937) (z = 6.29) (z = 1.6) Bloom et al. 2008

  4. atmospheric extinction The amount of atmospheric extinction depends on the altitude of an object, being lowest at the zenith and at a maximum near the horizon. It is calculated by multiplying the standard atmospheric extinction curve by the mean airmass calculated over the duration of the observation: Airmass = sec(z), z = zenith angle

  5. Spectrum of star HD144470: the only line produced in the Stellar atmosphere is He 7065, the rest are telluric

  6. The Milky Way in Infrared (2MASS survey) Note the Galactic Plane

  7. Extinction curves of our Galaxy and Magellanic Clouds 2175 Å: graphite or PAH?

  8. Dust suppression along given sight lines is estimated from COBE Infrared maps: Schlegel, Finkbeiner, Davis 1998, ApJ, 500, 525

  9. Neutral gas in our Galaxy absorbs thru photoelectric effect. This is predominantly neutral hydrogen (HI): the Lyman limit occurs at 912 Å = 13.6 eV At frequencies higher than 13.6 eV part of the X-ray flux is Absorbed, in a frequency-dependent way Morrison & McCammon (1983, ApJ, 270, 119) have computed this dependence in the 0.03 - 10 keV energy interval, taking into account cosmic abundances

  10. Hydrogen atom One  = 21 cm (1420 MHz) photon is emitted when the proton And electron spins flip from parallel to antiparallel.

  11. Radio and far infrared images of M81 (3.6 Mpc)

  12. The Antennae (22 Mpc) White: optical Blue: radio (21cm)

  13. High-z QSO spectra (Becker et al. 2001) The Intergalactic medium Absorbs radiation: Lyman alpha forest And Lyman continuum In high redshift quasars: intervening absorption by Clouds of neutral hydrogen

  14. Elihu Boldt The Extreme Universe: Some Views From Here Closing lecture, 3rd INTEGRAL Workshop: The Extreme Universe, Taormina, September 14-18 1998 Astrophysical Letters & Communications Vol. 37, 1999 arXiv:astro-ph/9902040

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