| |
 |
| Paper: |
Deep Chandra observation of the binary/lensed BALQSO UM 425 |
| Volume: |
290, Active Galactic Nuclei: from Central Engine to Host Galaxy |
| Page: |
179 |
| Authors: |
Aldcroft, T.; Green, P.; Siemiginowska, A. L.; Mathur, S. |
| Abstract: |
We have obtained a 120 ksec Chandra ACIS-S exposure of UM425, a bright gravitationally lensed Broad Absorption Line (BAL) QSO. BALQSOs may exist in every quasar when seen at the proper orientation, or they may represent an early or high L/LEdd phase of quasar evolution. Our spectrum of UM425 (the brighter "A" component) has approximately 5000 counts, and is well fit with a power law (photon spectral index of 1.7) absorbed by a partially covering cloud having a Hydrogen column of 2.5 x 1022 / cm2. These parameters and the optical to X-ray slope are consistent with the interpretation that UM425 is a normal QSO which is hidden behind a shroud of obscuring material. We also examine the emission from the fainter lensed image UM425B, which is approximately 60 times fainter than UM425A in the optical. In the X-rays we find a ratio of 170, and we investigate possible sources of this discrepancy, including variability and absorption by the lensing galaxy. |
|
|
|
|
|
