1. Magnetar SGR 1745-2900 By Christina Balanduk

2. SGR
SGR was discovered to be a magnetar orbiting about 0.3 ly from SGR A*, the supermassive black hole at the center of the Milky Way.

3. So, what is a Magnetar? -Neutron star -Average diameter of about 20 km
-Average density of about 10^17 kg/m^3
-Strongest known magnets in the universe
-Powered by magnetic field

4. Formation -Type 2 supernova
-May require a companion to form a Magnetar
-Theory formed through observing star cluster Wunderlund 1 and Magnetar CXOU J
“The rapid rotation created by mass transfer between the two stars appears necessary to generate the ultra-strong magnetic field, and then a second mass transfer phase allows the magnetar-to-be to slim down sufficiently so that it does not collapse into a black hole at the moment of its death.”
Info from Astronomy Magazine

5. from Chandra x-ray observatory.

6. How SGR 1745-2900 was discovered
-First observed in April 2013
-Discovered by many space telescopes including the Chandra X-ray Observatory.
-Discovered as it was entering an outburst in the Radio and X-ray bands
-Closest neutron star discovered to a supermassive black hole to date.
from Chandra X-Ray Observatory

7. X-ray bursts
-When matter is gravitationally pulled to an object it enters an accretion disk around the object as it orbits, continuously getting closer and closer to the object’s surface.
-As additional mass eventually gets to the surface of a neutron star it heats up due to the additional pressure of more and more mass being added.
-At some point this mass reaches high enough temperatures that hydrogen fusion turns on
-Quick and high intensity batches of hydrogen fusion occur causing an X-ray burst!
info from Astronomy Today

8. Simultaneous Multi-Band Radio & X-Ray Observations Article
-Observed SGR for 100 days after the initial discovery of this magnetar
-Observed in X-ray and Radio band
-Detected three separate bursts
-Found Radio emission to be delayed after the detection of the X-ray burst
-Something odd

9. X-Ray Outbursts Article
-Found SGR to have a higher temperature than non-magnetic models could predict
-Slow radio flux decay (noted by both articles)

10. What have we learned about Magnetars from SGR 1745-2900?
-We’ve learned that there’s something off about our model of crustal cooling in magnetars
-More research and modeling needs to be done into the radio flux decay of magnetars

11. Bibliography
Garching Magnetar formation mystery solved? Astronomy Magazine, May 14
Chandra x-ray observatory SGR : Magnetar Near Supermassive Black Hole Delivers Surprises
Pennucci TT, Possenti A, Esposito P, Rea N, Haggard D, et al simultaneous multi-band radio and x-ray observations of the galactic center magnetar SGR , ApJ. 808: 81-96
Coti Zelati F, Rea N, Papitto A, Viganò D, Pons JA, et al the x-ray outburst of the galactic centre magnetar SGR J during the first 1.5 year 449:
Chaisson E, McMillan S neutron stars and black holes. Astronomy today. Whilton N, Kenney L, Goodwin T. 8: