Relativistic Jets from the Black Hole in SS 433

Transcription

1 Relativistic Jets from the Black Hole in SS 433 Herman L. Marshall and Laura A. Lopez with Claude R. Canizares, Norbert S. Schulz, and Julie F. Kane MIT Center for Space Research using NASA s Chandra X-ray Observatory

2 Summary The sizes of the companion star and the jets are too small to image: < X-ray spectroscopy was used to image the hottest part of the jets and their changes, giving a measure of the location where and how jets are formed around a black hole. By measuring the jets, we find that the compact object is a black hole, with a mass of 16 ± 4 M sun. Quasar jets are thought to be similar but millions of times larger, so SS 433 provides a jet laboratory close to home. An artists rendition of the SS 433 system

3 Lines are from many ionized elements The ions are formed in a wide range of temperature jets cool from 100 to 10 million degrees Density is measured from a Si line group Lines are broad due to jet expansion and broadened between observations Red jet is weak in 1999 due to a Doppler effect but is comparable to the blue jet in 2001

4 Where are the SS 433 Jets Launched? Emission line widths provide the jet expansion velocity. The expansion velocity goes up as the temperature at the base of the jet increases. The temperature above the disk is highest near the black hole. Therefore, broader lines indicate smaller jet bases, decreasing from 100 to 20 Schwarzschild radii (the radius of the black hole).

5 March 2001 jet base Sept jet base Earth Moon

6 During eclipse, the X-rays from the coolest portion of the receding jet are blocked. With X-ray spectroscopy, we can determine the length of visible portion of receding jet and then the size of the companion. Optical results give the ratio of the masses using the orbital period and the radial velocity of the disk. Finally, we use the size of the companion star to determine the compact object s mass.

7 Modelling the X-ray Spectrum - 1 Break down the jet into 4 parts. Vary the amount of material observed in each part of the jet. Compare the model to the data. Discover where no jet emission is observed to determine the jet length.

8 Modelling the X-ray Spectrum - 2 Too Much: Three Visible Parts Sulfur Too Little: One Visible Part Silicon Silicon

9 Modelling the X-ray Spectrum - 3 Just Right: Two Components As the jet expands, its density and temperature decrease. With the relationship between density and jet length, we find the visible jet length: 10 6 km, 2.5 times the distance to the Moon.

10 Red Jet Geometry Companion Orbit semimajor axis 10 6 km Accretion disk Blue Jet Compact Object is a BLACK HOLE!

11 Summary The sizes of the companion star and the jets are too small to image: < X-ray spectroscopy was used to image the hottest part of the jets and their changes, giving a measure of the location where jets are formed around a black hole being launched 5 times closer to the black hole. By measuring the jets, we find that the compact object is a black hole, with a mass of 16 ± 4 M sun. Quasar jets are thought to be similar but millions of times larger, so SS 433 provides a jet laboratory close to home. An artists rendition of the SS 433 system