mssl astrophysics group start Terribly hot stars. Liz Puchnarewicz Mullard Space Science Laboratory, UCL  -ray sources, missions and stars

mssl astrophysics group introduction  -rays models breakthrough new missions Terribly hot stars.  -ray sources, missions and stars a brief history of  -ray astronomy and a look at the  -ray universe models – collisions, hypernovae and others finding  -rays: mapping and measuring - SWIFT and MSSL’s UVOT where do we see  -rays? what does a g-ray burst look like? bored Beppo-SAX, with backup from Hubble, makes a real breakthrough

mssl astrophysics group introduction next cosmic  -ray sources had been expected for several years. Cosmic rays + ISM supernovae high-E electrons + mag field  -ray CR  -ray

mssl astrophysics group Introduction first crucial results next OSO-3 COS-B SAS-2 First significant detection of  -rays from our galaxy. 621 cosmic  -rays SAS-2 (NASA) and COS-B (ESA) first mapped the  -ray sky detected the first point sources

mssl astrophysics group Introduction first conclusions next 1973 GRBs confirmed by SAS-2 and COS-B BUT distance and origin were unknown SO energy in burst unknown SO concluded that sources were in our Galaxy, possibly reconnection of neutron star magnetic field lines with the ISM magnetic field (ie analogous to solar flares).

mssl astrophysics group introduction back to menu

mssl astrophysics group  -rays next a  -ray burst occurs about three times a day in seconds-to-minutes, it emits more energy than any other known phenomenon (apart from the Big Bang) they are distributed evenly over the sky they are very hard to study because they disappear before you can ‘catch’ them. they are very, very hot

mssl astrophysics group  -rays back to menu 1.Extragalactic in origin 2.VERY energetic (up to 10 ergs) (only surpassed by the Big Bang) 3.VERY quick (30msec to 1.6 hours) – so must be emitted from a region only a few 10s of kilometres across So what are  -rays? 53

mssl astrophysics group models neutron star mergers next System emits radiation as neutron stars spiral inwards. Merger occurs once every 10,000 to a million years in a galaxy.

mssl astrophysics group models next A popular model for the origin of  -ray bursts is in the merger of two neutron stars.

mssl astrophysics group models the proton problem next

mssl astrophysics group models black hole forms next two stars collide Forms a black hole plus a disc Relativistic jets emerge along disc axis

mssl astrophysics group models where they might come from back to menu spatial distribution of counterparts hypernovae coalescing neutron stars density of counterparts distance from centre of host coalescing neutron stars hypernovae

mssl astrophysics group Beppo-SAX next

mssl astrophysics group Beppo-Sax makes the breakthrough next 8 hours after burst2 days later

mssl astrophysics group Beppo-SAX Hubble points to a galaxy back to menu

mssl astrophysics group new missions next New campaign strategies - SWIFT

mssl astrophysics group new missions next Once a burst has been detected, the telescope will slew to position within seconds X-ray positions to 2.5arcseconds UVOT positions to 0.3arcseconds

mssl astrophysics group campaigns back to menu * identify host galaxies uniquely by obtaining arcsec positions * measure redshift distribution to determine energetics, cosmological evolution, and GRB luminosity function * locate GRBs relative to host galaxies * constrain burst environment using X-ray absorption and optical reddening * use optical/X-ray afterglow as high redshift beacons * measure Ly-alpha forest * use X-ray absorption to probe intergalactic/cluster medium * extend star formation rate observations to high redshift Aims of the SWIFT mission

mssl astrophysics group start again the end Liz Puchnarewicz Mullard Space Science Laboratory, UCL