NuSTAR reveals an intrinsically X-ray weak broad absorption line quasar in the ultraluminous infrared galaxy Markarian 231

Journal Article · Thu Apr 10 00:00:00 EDT 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/785/1/19· OSTI ID:22357188

Teng, Stacy H.; Rigby, J. R. ^[1]; Brandt, W. N.; Luo, B. ^[2]; Harrison, F. A.; Grefenstette, B. W.; Madsen, K. K. ^[3]; Alexander, D. M.; Gandhi, P. ^[4]; Bauer, F. E. ^[5]; Boggs, S. E.; Craig, W. W. ^[6]; Christensen, F. E. ^[7]; Comastri, A. ^[8]; Fabian, A. C. ^[9]; Farrah, D. ^[10]; Fiore, F. ^[11]; Hailey, C. J. ^[12]; Hickox, R. C. ^[13]; others, and

---

1. Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
2. Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States)
3. Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)
4. Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)
5. Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile)
6. Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)
7. DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark)
8. INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy)
9. Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom)
10. Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States)
11. Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio Catone (Italy)
12. Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States)
13. Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States)

We present high-energy (3-30 keV) NuSTAR observations of the nearest quasar, the ultraluminous infrared galaxy (ULIRG) Markarian 231 (Mrk 231), supplemented with new and simultaneous low-energy (0.5-8 keV) data from Chandra. The source was detected, though at much fainter levels than previously reported, likely due to contamination in the large apertures of previous non-focusing hard X-ray telescopes. The full band (0.5-30 keV) X-ray spectrum suggests the active galactic nucleus (AGN) in Mrk 231 is absorbed by a patchy and Compton-thin (N{sub H}∼1.2{sub −0.3}{sup +0.3}×10{sup 23} cm{sup –2}) column. The intrinsic X-ray luminosity (L {sub 0.5–30} {sub keV} ∼ 1.0 × 10{sup 43} erg s{sup –1}) is extremely weak relative to the bolometric luminosity where the 2-10 keV to bolometric luminosity ratio is ∼0.03% compared to the typical values of 2%-15%. Additionally, Mrk 231 has a low X-ray-to-optical power law slope (α{sub OX} ∼ –1.7). It is a local example of a low-ionization broad absorption line quasar that is intrinsically X-ray weak. The weak ionizing continuum may explain the lack of mid-infrared [O IV], [Ne V], and [Ne VI] fine-structure emission lines which are present in sources with otherwise similar AGN properties. We argue that the intrinsic X-ray weakness may be a result of the super-Eddington accretion occurring in the nucleus of this ULIRG, and may also be naturally related to the powerful wind event seen in Mrk 231, a merger remnant escaping from its dusty cocoon.

• OSTI ID: 22357188
• Journal Information: Astrophysical Journal, Vol. 785, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION
APERTURES
BOLOMETERS
COMPARATIVE EVALUATIONS
EMISSION
FINE STRUCTURE
HARD X RADIATION
KEV RANGE
LUMINOSITY
MARKARIAN GALAXIES
QUASARS
X-RAY GALAXIES
X-RAY SPECTRA