Free Astronomy Magazine January-February 2015

SPACE CHRONICLES SDSS1133 would represent the lon- gest period of LBV eruptions ever observed, followed by a terminal supernova ex- plosion whose light reached Earth in 2001. The nearest analog in our galaxy is the massive binary system Eta Cari- nae, which in- cludes an LBV c o n t a i n i n g about 90 times the sun's mass. Between 1838 and 1845, the system under- went an out- burst that ejected at least 10 solar masses and made it the second-brightest star in the sky. It then followed up with a smaller eruption in the 1890s. For an LBV to explain SDSS1133, the star must have been in nearly con- tinual eruption from at least 1950 to 2001, when it reached peak brightness and went supernova. The spatial resolution and sensi- tivity of telescopes prior to 1950 were insufficient to detect the source. But if this was an LBV erup- tion, the current record already shows it to be the longest and most persistent one ever observed. An interaction between the ejected gas and the explosion's blast wave could explain the object's steady brightness in the ultraviolet. Whether it's a rogue supermassive black hole or the closing act of a rare star, it seems astronomers have never seen the likes of SDSS1133 before. T he PS1 Observatory on Haleakala, Maui just before sunrise. Mauna Kea on the island of Hawaii is in the background. Visible through the dome shutter are the calibration screen, the secondary mirror baffle, the truss and the primary mirror covers. The spikes on the outside of the dome are lightning rods. [Rob Ratkowski] Z oom into Markarian 177 and SDSS1133 and see how they compare with a simulated galaxy collision. When the central black holes in these galaxies combine, a “kick” launches the merged black hole on a wide orbit taking it far from the galaxy’s core. [NASA's Goddard Space Flight Center/L. Blecha (UMD)] rich, the Swiss Federal Institute of Technology. "But, one exciting dis- covery made with NASA's Swift is that the emission of ultraviolet light of SDSS1133 hasn't changed for a decade, which is not something typ- ically seen in a young supernova remnant." To analyze the object in greater de- tail, the team is planning ultraviolet observations with the Cosmic Ori- gins Spectrograph aboard the Hub- ble Space Telescope in October 2015. “We found in the Pan-STARRS1 im- aging that SDSS1133 has been get- ting significantly brighter at visible wavelengths over the last 6 months and that bolstered the black hole in- terpretation and our case to study SDSS1133 now with HST,” said Yan- xia Li a UH Manoa graduate student involved in the analysis of the Pan- STARRS1 imaging in the study. If SDSS1133 isn't a black hole, then it must have been a very unusual type of star known as a Luminous Blue Variable (LBV). These stars undergo episodic erup- tions that cast large amounts of mass into space long before they explode. Interpreted in this way, n