PEERING THROUGH the DUST: NuSTAR OBSERVATIONS of TWO FIRST-2MASS RED QUASARS

Stephanie M. Lamassa, Angelo Ricarte, Eilat Glikman, C. Megan Urry, Daniel Stern, Tahir Yaqoob, George B. Lansbury, Francesca Civano, Steve E. Boggs, W. N. Brandt, Chien Ting J. Chen, Finn E. Christensen, William W. Craig, Chuck J. Hailey, Fiona Harrison, Ryan C. Hickox, Michael Koss, Claudio Ricci, Ezequiel Treister, Will Zhang

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Some reddened quasars appear to be transitional objects in the paradigm of merger-induced black hole growth/galaxy evolution, where a heavily obscured nucleus starts to be unveiled by powerful quasar winds evacuating the surrounding cocoon of dust and gas. Hard X-ray observations are able to peer through this gas and dust, revealing the properties of circumnuclear obscuration. Here, we present NuSTAR and XMM-Newton/Chandra observations of FIRST-2MASS-selected red quasars F2M 0830+3759 and F2M 1227+3214. We find that though F2M 0830+3759 is moderately obscured (NH,Z = (2.1 ±0.2) ×1022 cm-2) and F2M 1227+3214 is mildly absorbed (NH,Z = 3.4-0.07+0.8 × 1021 cm-2) along the line of sight, heavier global obscuration may be present in both sources, with NH,S = 3.7-2.6+4.1 × 1023 cm-2 and <5.5 ×1023 cm-2 for F2M 0830+3759 and F2M 1227+3214, respectively. F2M 0830+3759 also has an excess of soft X-ray emission below 1 keV, which is well accommodated by a model where 7% of the intrinsic X-ray emission from the active galactic nucleus (AGN) is scattered into the line of sight. While F2M 1227+3214 has a dust-to-gas ratio (E(B - V)/NH) consistent with the Galactic value, the value of E(B - V)/NH for F2M 0830+3759 is lower than the Galactic standard, consistent with the paradigm that the dust resides on galactic scales while the X-ray reprocessing gas originates within the dust sublimation zone of the broad-line region. The X-ray and 6.1 μm luminosities of these red quasars are consistent with the empirical relations derived for high-luminosity, unobscured quasars, extending the parameter space of obscured AGNs previously observed by NuSTAR to higher luminosities.

Original languageEnglish (US)
Article number70
JournalAstrophysical Journal
Volume820
Issue number1
DOIs
StatePublished - Mar 20 2016

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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