ESA's XMM-Newton has found a pulsar - the spinning remains of a once-massive star - that is a thousand times brighter than previously thought possible. The pulsar is also the most distant of its kind ever detected, with its light travelling 50 million light-years before being detected by XMM-Newton. Read more
Title: ULX-1 in NGC5907: how bright can an accreting pulsar shine? Author: G. L. Israel, A. Belfiore, L. Stella, P. Esposito, P. Casella, A. De Luca, M. Marelli, A. Papitto, M. Perri, S. Puccetti, G. A. Rodriguez Castillo, D. Salvetti, A. Tiengo, L. Zampieri, D. D'Agostino, J. Greiner, F. Haberl, G. Novara, R. Salvaterra, R. Turolla, M. Watson, J. Wilms, A. Wolter
Non-nuclear ultraluminous x-ray sources (ULXs) in nearby galaxies shine brighter than any source in our Galaxy. ULXs are usually modelled as stellar-mass black holes accreting at very high rates or intermediate-mass black-holes. We have discovered that ULX-1 in NGC 5907 is an x-ray accreting neutron star (NS) with a spin period evolving from 1.43 s in 2003 to 1.13 s in 2014. With an isotropic peak luminosity of ~500 times the Eddington limit for a NS at 17.1 Mpc, it is the most luminous and distant x-ray pulsar ever detected. Standard accretion models fail to explain its luminosity, even assuming beamed emission. We show that a strong multipolar magnetic field, similar to that of magnetars, can describe its properties. These findings suggest that other extreme ULXs might harbour NSs.
NGC 5907 (also Splinter Galaxy, Knife Edge galaxy, IRAS 15146+5629, MCG 9-25-40, UGC 9801 and PGC 54470) is a magnitude +11.1 edge-on spiral galaxy located 53.5 ±8.1 million light-years away in the constellation Draco. The galaxy was discovered by German-British astronomer William Herschel using a 47.5 cm (18.7 inch) f/13 speculum reflector at Windsor Road, Slough on the 5th May 1788. The galaxy hosted supernova 1940A which reached magnitude 14.3
Right Ascension 15h 15m 53.8s, Declination +56° 19' 44"
La galaxie spirale NGC 5907, dans la constellation du Dragon, serait née d'une collision-fusion majeure survenue il y a 8 à 9 milliards d'années. C'est la conclusion que tirent six chercheurs de l'Observatoire de Paris, du CNRS, de l'Académie des sciences chinoise et d'Aix-Marseille Université après 18 mois de travail et des simulations numériques impliquant 200 000 à 6 millions de particules qui expliquent - en images - comment s'est formé ce vaste ensemble de gaz et d'étoiles entouré de boucles de matière. Les résultats, publiés en ligne le 13 février 2012 par Astronomy and Astrophysics, constituent un test des scénarios cosmologiques. Read more