* Astronomy

Title: The Chandra view of the Largest Quasar Lens SDSS J1029+2623
Authors: Naomi Ota, Masamune Oguri, Xinyu Dai, Christopher S. Kochanek, Gordon T. Richards, Eran O. Ofek, Roger D. Blandford, Tim Schrabback, Naohisa Inada

We present results from Chandra observations of the z_l=0.58 cluster lens SDSS J1029+2623, which is presently the largest separation gravitationally lensed quasar. We clearly detect X-ray emission both from the lensing cluster and the three lensed quasar images. The cluster has an X-ray temperature of kT = 8.1 (+2.0, -1.2) keV and luminosity L_X = 9.6e44 erg s^-1. Its surface brightness is centred near galaxy G2 and it is elongated East-West. We identify a subpeak North-West of the main peak, which is suggestive of an ongoing merger. Even so, the X-ray mass inferred from the hydrostatic equilibrium assumption appears to be consistent with the Einstein radius of the system. We find significant absorption in the soft X-ray spectrum of quasar image C, which can be caused by an intervening material at either the lens or source redshift. The X-ray flux ratios between the quasar images after correcting for absorption are in reasonable agreement with those at optical and radio wavelengths. This implies that microlensing effect is not significant for this system and dark matter substructure is mainly responsible for the anomalous flux ratios.

Read more (1509kb, PDF)